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2012 Seminars

  • Thu 2 Feb, 2012 - 12:15pm

    Dr Volker Nock

    Electrical and Computer Engineering, University of Canterbury

    Abstract

    The interface between man-made micro- and nanodevices and biological
    systems has been gaining increasing interest due to the potential impact
    of such devices on healthcare and medical science. In this presentation I
    will explore the breadth of my personal involvement in this field by
    introducing several current projects covering a novel laminar flow-based
    surface patterning method, digital microfluidics based on droplet
    coalescence and self-propulsion, construction of gut-like structures
    through stem cell tissue engineering, a device for the study of force
    patterns in worm locomotion, bioimprinted cell-culture scaffolds and the
    generation of oxygen microenvironments on chip.

  • Thu 1 Mar, 2012 - 12:15pm

    Terry L. Gustafson

    Photon Factory, University of Auckland and Center for Chemical and Biophysical Dynamics, Ohio State University

    The design of systems for the efficient conversion of the solar spectrum to other forms of useful energy is an on-going challenge in the pursuit of alternative energy sources. Expanding the fraction of the solar spectrum that can be used by devices is an important aspect of most efforts to improve the efficiency of solar cells.

    One approach to enhancing the fraction of the solar spectrum that is captured is to sensitize semiconductor materials with molecules with broad absorption features across the visible and near-infrared spectral regions. There are important fundamental requirements related to the rational design of molecules for sensitization. These molecular properties include broad absorption features, energy levels compatible with appropriate semiconductor materials, efficient energy or electron transfer across interfaces, and photostability.

    We are studying a class of metal-metal quadruply bounded compounds for use in a variety of molecular electronics, including photosensitization. The compounds studied have the general molecular formula trans-M2(X2C-L)2(X2CL’)2, where M = Mo or W, X = NiPr or O, and L and L’ represent organic groups. Compounds of this type are known to possess low energy states that can be described as metal-to-ligand charge transfer (MLCT) or metal-centered (δδ*) in both the singlet and triplet manifolds where the ordering of these states depends strongly on the nature of the chosen metal and the ligand organic π-conjugation. We are using steady-state and time-resolved electronic and vibrational spectroscopy to investigate the photophysical and photochemical properties of this class of molecules.

    Venues

    • Victoria University of Wellington, Room RB105
    • University of Otago, Teaching & Learning Facilities, AVC2
    • University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    • Massey University, Science Block, Room to be advised
    • Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    • University of Canterbury – HP Seminar Room, NZi3

    If you are unable to attend at one of the above locations the seminar can be viewed via Scopia Desktop

  • Thu 5 Apr, 2012 - 12:15pm - 1:00pm

    Our cells, the ones that join together to make our bodies, are fairly small.  Even smaller, sometimes much smaller, are the shapes that nanofabrication can provide.

    The results of projects mixing these aspects are expected to impact strongly on health, both well-being and recovery from disease. Imaging methods, such as AFM produce 3-D information, at the nanoscale level, on the morphologies of pores through which cells release compounds that transmit messages from one tissue to another.

    It appears that these messages are altered according to the physical environment of the cell. Polymers have been used to make moulds of cell populations as Bioimprints and these were used as substrates for other cells to grow on. Our results, indeed, indicate that both the topology of the substrate and its chemical nature affect cell activity.

    The opposite perspective, of examining individual cells that are isolated from interactions with neighbours, is being approached by fabricating chips that allow study of cells with addresses that can be repeatedly revisited. Microfluidics is applied so artificial solutions flow around the cells.  It appears that poking cells or altering the micro- or nano-environment, and thus the mechanical forces at the surface, might lead to a cure for cancer, make injured muscles grow again, and direct cosmetic changes.

  • Thu 3 May, 2012 - 12:15pm - 1:00pm

    Dr Richard McKenzie, Principal Scientist, NIWA

    The UV environment in New Zealand is compared with that in other locations, and the implications for human health of its large seasonal variability are discussed. High levels of UV in summer contribute to skin cancer risk, but low levels of UV in winter contribute to vitamin D deficiency which can have a multiplicity of adverse health effects. The UV exposures needed to attain optimal vitamin D without inducing skin damage (sunburn) are estimated. However the results of that calculation show that our understanding of the production of vitamin D through exposure of the skin to sunlight may be incorrect.Preliminary results of a study investigating the relationship between vitamin D status and UV exposure, as measured by novel personal dosimeter badges developed by Dr Martin Allen (MacDiarmid Institute), are presented. These results suggest that the currently accepted action spectrum for the production of pre-vitamin D in the skin may not be correct and that production of vitamin D from winter sunlight is more problematic than estimated previously.


    Venues

    Victoria University of Wellington, Room RB105
    University of Otago, Teaching & Learning Facilities, AVC2
    University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    Massey University, Science Block, Room to be advised
    Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    University of Canterbury – Kirkwood Village, KE06

    If you are unable to attend at one of the above locations the seminar can be viewed via Scopia Desktop


    Richard McKenzie is principal scientist for radiation at NIWA and is based at their atmospheric research laboratory at Laude, Central Otago. He has degrees in physics from the University of Canterbury and the University of the South Pacific (Fiji), and received a doctorate in atmospheric physics from the University of Oxford, England. He is a world leader in UV research and he also works closely with health advisors. He has contributed to numerous international reports on the science of ozone depletion and climate change commissioned by the World meteorological Organisation (WMO) and the Intergovernmental Panel on Climate Change (IPCC). He is currently a member of a United Nations Panel that reports to the parties of the Montreal Protocol on the Environmental Impacts of Ozone Depletion and Interactions with Climate Change. He lives in Alexandra.

  • Thu 7 Jun, 2012 - 12:15pm - 1:00pm

    Hide-and-seek games in resonant Raman spectroscopy

    Dr Baptiste Auguié
    Victoria University of Wellington

    A persistent challenge in Raman spectroscopy has always been the characterisation of resonant dye molecules, where an overwhelming fluorescence often masks the weak Raman signals, with an intensity ratio that can reach as much as 5 orders of magnitude.

    A noise analysis performed on a standard Raman spectrometer demonstrates that a naïve averaging procedure – increasing of the number of acquisitions – is not sufficient to reveal the Raman peaks above the noise level. Our group recently investigated two practical techniques to overcome this issue and regain a signal-to-noise ratio only limited by the acquisition time (shot noise). I will describe these two techniques and illustrate their great potential in resonant Raman spectroscopy with our most recent experimental results. Furthermore, I will show that the second method is applicable to a much wider range of spectroscopic and/or imaging measurements, where a weak signal is swamped in an overwhelming background.

    Fermi surface reconstruction and pseudogap asymmetry in the high-Tc cuprates

    Dr James Storey
    Industrial Research Limited

    Twenty six years since their discovery the origin of superconductivity in the cuprate high-temperature superconductors remains a major outstanding challenge in physics and an active area of research in the MacDiarmid Institute.Their relatively simple layered two-dimensional crystal structure conceals an extremely rich electronic behaviour as a function of hole doping.

    Recently, we have found that evidence from NMR of a two-component spin system is paralleled by similar evidence from the electronic entropy so that a two-component quasiparticle fluid is implicated. We propose that this two-component behaviour arises from reconstruction of the energy-momentum dispersion into two branches, giving rise to a particle-hole asymmetric pseudogap and small Fermi surface pockets. If correct then it follows that single-component electronic behavior will be recovered when the pseudogap closes in the overdoped regime.We illustrate this by calculating the spin susceptibility using a resonating valence bond spin liquid model, finding excellent agreement with the NMR results. The possible detection of electron-like Fermi surface pockets in the thermopower will also be presented.


    Venues

    Victoria University of Wellington, Room RB105
    University of Otago, Teaching & Learning Facilities, AVC2
    University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    Massey University, Science Block, Room to be advised
    Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    University of Canterbury – Kirkwood Village, KE06

  • Thu 5 Jul, 2012 - 12:15pm - 1:00pm

    Dr Bob Buckley, Industrial Research Limited

    There are significant challenges in translating R&D into economic outcomes in New Zealand as expected by government and private sector investors. Through the development of a range of HTS technologies and their subsequence commercialisation we have developed an approach which is working. I will talk about the journey we went on, what we have learned, the outcomes achieved, along with the opportunities that with the right investment and partners are yet to be addressed.     

     

    Venues

    Victoria University of Wellington, Room RB105
    University of Otago, Teaching & Learning Facilities, AVC2
    University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    Massey University, Science Block, Room to be advised
    Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    University of Canterbury – Kirkwood Village, KE06

    If you are unable to attend at one of the above locations the seminar can be viewed via Scopia Desktop

  • Thu 2 Aug, 2012 - 12:15pm - 1:00pm

    The Future of Solar Technology as Clean Energy

    Emerging new technologies and materials investigated in Japan aimed to increase the efficiency and to reduce the cost of solar power generation will also be reviewed.

    (1)     Overview

             History, cultural background of Japanese solar cell research and industry.

    (2)     New Technologies

             CPV: Concentrating Photovoltaics Technology.

    (3)     Materials

             The tandem solar cell and the nano structure solar cell.

    (4)     Review

             Discuss methods to improve efficiency and reduce the cost.


    Venues

    Victoria University of Wellington, Room RB105
    University of Otago - via Skopia Desktop
    University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    Massey University, Science Block, Room to be advised
    Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    University of Canterbury – Kirkwood Village, KE06

    If you are unable to attend at one of the above locations the seminar can be viewed via Scopia Desktop

  • Thu 2 Aug, 2012 - 12:15pm - 1:00pm

    Upcoming Seminars

    Fishing for Chloride in Salty Waters using Photoactive Foldamers
    Date:Thu 4th October 2012 - 12:15pm - 1:00pm
    Professor Amar H. Flood, Dept. of Chemistry, Indiana University, USA

    Recent Seminars:

    Gold, silver and copper
    Thu 6th September
    Dr Doreen Mollenhauer, Industrial Research Limited
    Dr Nadia Grillet, University of Canterbury

    The Future of Solar Technology as Clean Energy
    Thu 2nd August 2012 - 12:15pm - 1:00pm
    Professor Yoshitaka Okada, Research Center for Advanced Science and Technology, The University of Tokyo

    Thu 5 Jul, 2012 - 12:15pm - 1:00pm

    Dr Bob Buckley, Industrial Research Limited

    Resonant Raman Spectroscopy and Origins of Superconductivity
    Thu, 7 June 2012 - 12:15pm - 1:00pm
    James Storey ,  Industrial Research Limited
    Baptiste Auguie, Victoria University of Wellington

    UV radiation in New Zealand: implications for health
    Thu, 3 May 2012 - 12:15pm - 1:00pm
    Dr Richard McKenzie, Principal Scientist, NIWA

    When the fairly small bits meet the tiny, tiny bits … different things will happen
    Thu, 5 April 2012 - 12:15pm - 1:00pm
    John Evans, Christchurch School of Medicine, University of Otago, Christchurch

    Thu, 1 March 2012 - 12:15pm - 1:00pm

    Terry L. Gustafson, Photon Factory, University of Auckland and Center for Chemical and Biophysical Dynamics, Ohio State University

    Thu, 2 February 2012 - 12:15pm - 1:00pm

    Dr Volker Nock, Electrical and Computer Engineering, University of Canterbury

     


    Venues:Powered by KAREN

    • Victoria University of Wellington, RB105, Rankin Brown Building
    • University of Otago, Teaching & Learning Facilities, AVC2
    • University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    • Massey University, Science Block, Room to be advised
    • Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    • University of Canterbury – Kirkwood Village, KE06

    If you are unable to attend at one of the above locations the seminar can be viewed via Scopia Desktop.

  • Thu 6 Sep, 2012 - 12:15pm - 1:00pm

    Dr Doreen Mollenhauer, Industrial Research Limited

    Dr Nadia Grillet, University of Canterbury

    Dr Doreen Mollenhauer
    Industrial Research Limited

    Towards the understanding of the chemical environment effect on small gold-containing clusters

    Gold clusters and nanoparticles have attracted continuing attention due to interesting and important electronic, catalytic and optical properties [1,2]. The understanding of the effect of the chemical environment on these properties is essential for a complete and realistic picture. In order to demonstrate the influence of the ligand shell on the electronic properties, we will present various gold clusters surrounded by phosphine ligands. To describe the system accurately, we have performed benchmark calculations including coupled cluster, MP2 and DFT approaches, as well as considering medium and long range dispersion effects via a dispersion correction. The need for such studies has been shown for example in investigations of gold systems with carbon monoxide [3] or pyridine [4]. Furthermore as bimetallic gold-palladium catalysts have been found to have improved catalytic properties in various reactions in comparison to the monometallic clusters, the influence of the ligand shell on the mixed clusters was also analyzed.
     

    [1]        M.-C. Daniel, D. Astruc, Chem. Rev., 104, 293 (2004).
    [2]        M. Turner, V. B. Golovko, O. P. H. Vaughan, P. Abdulkin, A. Berenguer-Murcia, M. S. Tikhov, B. F. G. Johnson, R. M.  Lambert,     Nature, 454, 981 (2008).
    [3]        P. Schwerdtfeger, M. Lein, R. P. Krawczyk, C. R. Jacob, J. Chem. Phys., 128, 124302 (2008).
    [4]        D. Mollenhauer, J. Floß, H.-U. Reissig, E. Voloshina, and B. Paulus, J. Comput. Chem. 32, 1839 (2011).



    Dr Nadia Grillet
    University of Canterbury

    Silver-copper nanoclusters: Structure and time evolution

    There is currently a great deal of interest in bimetallic nanoclusters because of both fundamental scientific questions and their possible technological applications. Ag-Cu clusters are of particular interest for the production of nanoscale chips. In our case, the clusters are prepared by inert gas aggregation in an ultra high vacuum compatible magnetron sputtering system (1). The structures have been observed by bright field high resolution Transmission Electron Microscopy (TEM) and high-angle annular dark field (HAADF) scanning TEM (2) as a function of the alloy composition, the coverage of the sample and the size of the clusters. Fresh Ag-Cu clusters have shown a very complex structure but over time a progressive rearrangement occurs, finally yielding well-ordered structures.

    [1]       R. Reichelet al., Journal of Nanoparticle Research 8, 405 (2006).
    [2]       Z. Y. Liet al., Nature 451, 46 (2007).

    Venues
    Victoria University of Wellington, Room RB105
    University of Otago, please use Scopia Desktop
    University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    Massey University, please use Scopia Desktop
    Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    University of Canterbury – Kirkwood Village, KE06

  • Thu 4 Oct, 2012 - 12:15pm - 1:00pm

    Fishing for Chloride in Salty Waters using Photoactive Polymers

    Chloride is an abundant ion that plays critical roles in human biology and chemical processes. For these reasons, mastering ways to manipulate its availability across many environments will have far-reaching consequences. We are focusing supramolecular chemistry onto this task by taking advantage of triazole-based receptors that are easy to make and modify. Taking inspiration from biology in the form of halorhodopsin, a new class of light-active foldamers has been created that can catch and release chloride to regulate its concentration. We will then move out of organic solvents, again taking biology’s lead, to tackle one of the grand challenges in host-guest chemistry: Extracting highly-hydrated chloride ions from aqueous solutions. We do so by employing the principles present in proteins like chloride channels (ClC), and for the first time with synthetic receptors, show that the hydrophobic effect can be used to extract hydrophilic guests equally as well as hydrophobic ones. Ultimately, we have learned about the important role that a foldamer’s helical propensity plays in determining its function.


    Venues
    Victoria University of Wellington, Room RB105
    University of Otago, please use Scopia Desktop
    University of Auckland, 23 Symonds St, Rm 411, Chemistry Building 301
    Massey University, please use Scopia Desktop
    Industrial Research Ltd – Gracefield Campus, C-Block Meeting Room
    University of Canterbury – Kirkwood Village, KE06