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Viewing upcoming talks containing the keyword: 3
Physics and Astronomy Colloquia
Speaker: Inga Kamp (University of Groningen)
The disks around young stars, protoplanetary disks, are thought to be the birthplaces of planetary systems such as our own.
Spitzer, Herschel and ground-based observations showed in several cases the existence of water in such disks around young stars and JWST will dig even deeper from 2018 on. On the other hand, Solar System exploration and observations of comets allow us to study specific processes in much more detail compared to protoplanetary disk research.
The combination of evidence from protoplanetary disks and our own Solar System is inspiring the discussion of how much water vapour and ice is present at early times to form gas giant planets, water worlds, but also at later times to deliver the Earth oceans and eventually lead to the emergence of life. I will discuss our current understanding of the chemistry in proptoplanetary disks, the water vapour and ice reservoirs and potential mixing processes and relate this to evidence collected within our own Solar System.
On: September 30, 2016 From: 10h00 To: 11h00View talk
Taking Bioinspired Catalysis a Step Further: Photoredox Activation and the Quest for new Artificial Metalloenzyme Scaffolds (Joint BSRC/EaStCHEM Colloquium)
Speaker: Anne Duhme-Klair (York)
Metalloproteins evolved over millions of years to adapt perfectly to their role in electron transfer and redox catalysis. Intrigued by the fundamental design principles found in many metalloenzymes, we set out to incorporate identified key building blocks into our synthetic models.
Mo-containing oxotransferases, for example, catalyse oxygen atom transfer (OAT) from water to organic substrates. In these enzymes, the two electrons that are released are rapidly removed, one at a time, by spatially-separated electron transfer units. Inspired by this design, a Ru(II)-Mo(VI) dyad was developed, in which the rate-determining step in the OAT cycle is accelerated via a photo-oxidation.1
In addition, we are searching for new protein scaffolds with the aim of imparting the selectivity and biocompatibility of enzymes onto organometallic catalysts. By investigating siderophore-mediated bacterial Fe(III) uptake, we found that tetradentate siderophores, such as the ferric-Linear Dimer (see figure below) bind strongly to certain periplasmic binding proteins.2 The potential biological implications of this finding and opportunities for applications will be presented.
1 A. B. Ducrot, B. A. Coulson, R. N. Perutz, A.-K. Duhme-Klair, Inorg Chem., submitted.
2 D. J. Raines, O. V.Â Moroz, E. V. Blagova, J. P. Turkenburg, K. S. Wilson, A.-K. Duhme-Klair, PNAS, 2016, 113, 5850.
On: October 12, 2016 From: 13h00 To: 14h00View talk
Speaker: Colin Campbell (Edinburgh)
Use of multicellular tumor spheroids (MTS) to investigate therapies has gainedimpetus because they have potential to mimic factors including zonation,hypoxia and drug-resistance. However, analysis remains difficult and oftendestroys 3D integrity. In our recent work we have developed an opticaltechnique using targeted nanosensors that allows in situ 3D mapping of redoxpotential gradients whilst retaining MTS morphology and function. Themagnitude of the redox potential gradient can be quantified as a free energydifference (Î”G) and used as a measurement of MTS viability. We found that bydelivering different doses of radiotherapy to MTS we could correlate loss of Î”Gwith increasing therapeutic dose. In addition, we found that resistance to drugtherapy was indicated by an increase in Î”G. This robust and reproducibletechnique allows interrogation of an in vitro tumor-model's bioenergeticresponse to therapy, indicating its potential as a tool for therapy development.
On: October 19, 2016 From: 15h30 To: 16h30View talk
Physics and Astronomy Colloquia
Speaker: Judith Driscoll (University of Cambridge)
Since the discovery of high temperature superconductivity in perovskite oxides in 1986, the unearthing of a huge range of physical phenomena in transition metal oxides (TMOs) has been nothing short of remarkable, e.g. new magnetics, ferroelectrics, multiferroics, semiconductors, transparent conductors, calorics, plasmonics, catalysts, ionic conductors. Nearly 150,000 papers were published on the topic â€˜oxide+thin filmâ€™ in the last 10 years, not far from the number published on graphene in this same period. However, there are few applications of complex oxide thin films today. The underlying reason is the lack of understanding of the materials, in terms of their defective nature and in terms of how to engineer them to be perfect and strained optimally. As stated in a recent perspective publication by the EU commission about emerging applications, â€œwe have passed from the perception that materials are in the drawer to the realisation that materials are the bottleneckâ€.
Addressing the oxide thin film bottleneck is long overdue. This talk will discuss new insight into oxide thin films. Then solutions to the problem from the author will be presented, with examples given of unprecedented functional property enhancements in systems such as ferroelectrics, ferromagnetics and ionics. Examples will also be given of the authorâ€™s work in the area of oxide superconductors which has enabled applications to take off.
On: October 28, 2016 From: 10h00 To: 11h00View talk
Exploring catalysis with iron(II) Î²-diketiminate complexes: From dehydrocoupling to hydrofunctionalization
Speaker: Ruth Webster (Bath)
Explo ring catalysis with iron (II) β -diketiminate complexes: From dehydrocoupling to hydrofunctionali zation Ruth L. Webster* Department of Chemistry, University of Bath, Claverton Down, Bath. UK email@example.com Abstract: The stoichiometric reactivity of β -diketiminate complexes is w ell reported in the literature, indeed the β -diketiminate pro -ligand has proven to be a work -horse of catalysis when utilized with a wide range of metals. However, the catalytic competency of iron β - diketiminate complexes is not well explored as a result, an area of interest for our research group is the development of catalytic competency with iron β -diketiminate complexes. We have already shown that they are proficient catalysts for the dehydrocoupling (DHC) of phosphines 1 (Scheme 1) and have extended the reactivity to phosphine -borane and amine -borane DHC, demonstrating that the system is competitive with seminal work using iron photocatalysis 2 with these substrates. In the pr esence of an olefin, a switch in reactivity t akes place and hydrofunctionaliz ation (hydroboration or hydrophosphination) dominates. Intriguingly, a change in solvent results in a vast change in rea ctivity . Our synthetic studies along with mechanistic insig hts will be discussed. References: 1. A. K. King, A. Buchard, M. F. Mahon and R. L. Webster, Chem. Eur. J. 2015 , 21 , 15960 -15963. 2. A. Schäfer, T. Jurca, J. Turner, J. R. Vance, K. Lee , V. A. Du, M. F. Haddow, G. R. Whittell and I. Manners , Angew . Chem. Int. Ed. 2015 , 54 , 4836 -4841. Download PDF
On: November 2, 2016 From: 15h30 To: 16h30View talk