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Viewing upcoming talks in: EaStCHEM Colloquia
Speaker: Prof Bruce Gibb (Tulane University)
Probing and harnessing the hydrophobic and Hofmeister Effect s A better understanding of how molecules interact in aqueous solutions has ramifications a cross the biosph ere, lithosphere, atmosphere, and hydrosphere . For example, aqueous solutions of dissolved organic molecul es and salts are central to all of biolo gy and biochemistry . Un surprisingly, documented studies of h ow organic solutes, dissolved sa lts, and water interact with each othe r arguably go back to at least the late 18 th Centur y with Franz Hoffmeister ’s seminal work on protein solubility . However, to date no comprehensive atomistic model of the interactions between this trinity of solute, s alt, and water has been forthcoming. For some time now , our research has focused on building up an atomistic view point of aqueous supramolecular chemistry. In doing so we envis age not only being able to subtly engineer and contro l specific molecular inte ractions at the atomistic level to engender un usu al phenomena , but also apply this information to build ing a better understanding of bulk phenomena such as solubility . This presentation will focus on o ur recent stu dies into aqueous supramolecular interact ions uti liz ing deep -cavity cavitands as models . We will discuss how these interactions control the bulk prop erties of the hosts, and how they can b e harnessed to yield novel supramolecular containers that function as yoctoliter reaction vess els and tools for bringing about separation protocols. 1 References 1. (a) Jordan, J. H.; Gibb, C. L. D.; Wishard, A.; Pham, T.; Gibb, B. C., J. Am. Chem. Soc. 2018, 140 (11), 4092 -4099; (b) Hill yer, M. B.; Ga n, H.; Gibb, B. C., ChemPhysC hem 2018, 19 (18), 2285 -2289; (c) Sokkalingam, P.; Shraberg, J.; Rick, S. W.; Gibb, B. C., J. Am. Chem. Soc. 2016, 138 (1), 48 -51; (d) Wa ng, K.; Gibb, B. C., J. Org. Chem. 2017, 82 , 4279 –4288. Download PDF
On: February 19, 2019 From: 16h00 To: 16h30View talk
Speaker: Prof Eric Anslyn (University of Texas at Austin)
“A Marriage of Supramolecular Chemistry wi th Chemometrics”
Over the last several years our group has worked in a field we have referred to as supramolecular analytical chemistry, where our own pursuits meld covalent and non -covalent organic/inorganic reactivity with standard analytical techniques such as chemometrics to create assays for various real - life applications. In this lecture, we will follow our thought process of moving away from highly selective receptors to low -selectivity receptors, and the creation of patterns that identif y a single analyte in complex mixtures, or that qualitatively differentiate between complex mixtures. The inspiration for this approach to chemical sensing is the mammalian senses of taste and smell, which will be briefly reviewed. The discussion will cent er on differential sensing as a means of fingerprinting mixtures of analytes whose structures are not even known, with a particular focus on kinases and beverages. Overall, this lecture will show that a combination of mechanistic organic chemistry with con cepts from supramolecular chemistry and chemometrics lead to the creation of novel, but also practical, advances in the analytical sciences. Download PDF
On: February 19, 2019 From: 16h30 To: 17h00View talk
Speaker: Siân Dutton (Cambridge)
Structural (dis)order as a pathway to functional materials Siân Dutton https://duttongroup.weebly.com/ Cavendish Laboratory, University of Cambridge, Cambridge, CB3 0HE
Resea rch in the Dutton group focuses on the synthesis and characterisation of functional energy materials. I will present results on our work on developing high voltage, high capacity cathodes for Mg -ion batteries and the emergent charges which arise in Ising Kagome lattices. Divalent Mg -ion batteri es offer an attractive alternative to Li -ion batteries due to the increased capacity offered by cycling a divalent cation and possibility of using a Mg metal anode. De spite demonstration of reversible cycling in the molybdenum sulphide chevrel phase over 1 5 years ago 1 improvements have been slow and limiting factors include the lack of a suitable electrolyte and challenges associated with intercalation of Mg 2+ at high voltages and multiple electron redox on an individual ions. I will present out results on pyro -, Mg xM2-xB2O5 and orthoborates, Mg xM3-x(BO 3)2 M = Mn,Fe,Co,Ni and discuss the role of disorder between Mg and M sites, and the crystal structure on the observed electrochemical properties .2,3 In the second part of the talk I will discuss the novel eme rgent charge order in Ising Kagome magnets. These are predicted to show formation of a number of exotic states on cooling, which differ significantly from their three -dimensional analogue, spin -ice. I will show how 3:1 ordering in pyrochlores, A3A’B 3B’O14, can be used to generate undistorted Kagome lattices and present results on the Ising system Dy 3Mg 2Sb 3O14. Bulk thermodynamic properties measurements, diffuse scattering and monte -carlo simulations will be used to demonstrate the existence of emergent cha rges below T* ~ 100 mK. 4 1 Aurbac h et al Nature, 407, 724 (2000) 2 Glass et al. Chemistry of Materials, 29(7), 3118 (2017) 3 Glass et al. in prepa ration 4 Paddison et al. Nature Communications, 7, 13842 (2016) Download PDF
On: February 20, 2019 From: 14h00 To: 15h00View talk
Cond Mat Seminars
Speaker: Sergey Borisenko (IFW Dresden)
I will overview our recent results on some key members of iron-based family of superconductors. Majority of these materials undergo or are close to a tetragonal-to-orthorhombic (nematic) transition which seems to be of electronic origin. It is currently highly debated whether the nematic fluctuations are so important that they can mediate the pairing itself. On the other hand, there is a controversy as to how strong the influence of the nematic ordering on the electronic structure probed by ARPES is, thus questioning the direct relation between nematicity and superconductivity. Intriguingly, it may actually appear that the latter drives the former.
On: February 20, 2019 From: 13h00 To: 14h00View talk
History of Mathematics
Speaker: Danny Otero (Xavier University, Cincinnati, USA)
The speaker is one of a team of seven mathematicians and mathematics educators, representing different universities across the United States, who have been at work to design, author, classroom test, revise, evaluate, and disseminate classroom modules called Primary Source Projects (PSPs), which are meant to teach standard topics from across the early years of the undergraduate mathematics curriculum through primary historical source materials. This endeavor, called by the acronym TRIUMPHS, intends for PSPs to replace traditional textbook presentations of mathematical content by focusing student attention on the interpretation of historical source texts combined with brief contextual material and carefully crafted exercises meant to encourage sense-making by students. PSPs are also designed to incorporate principles of active learning, wherein the bulk of classroom time is given over to student work on project tasks and exercises, both alone and in discussion with small groups of classmates, or involving the entire class, rather than to traditional lectures by the instructor.
The TRIUMPHS team, supported with funding from the US National Science Foundation, have created some 48 such modules together with a few external authors. These are now freely available from the TRIUMPHS website. Some PSPs can take as little as 30 minutes to implement, while others are designed to take up to four weeks (with median implementation time of about one week) of classroom time. There are modules written to support standard coursework from precalculus and calculus, linear algebra, differential equations, algebra, theory of numbers, geometry, analysis, statistics, and a few other subjects as well.
This talk will discuss the TRIUMPHS endeavor generally but will show examples of PSPs at work through a pair of projects authored by the speaker, one of which is an introduction to the study of trigonometry, the other of which teaches the matrix determinant.
On: February 21, 2019 From: 16h00 To: 17h00View talk
Physics and Astronomy Colloquia
Speaker: Dr. Laura Fabris (Rutgers Materials Science and Engineering)
Near field techniques, such as surface enhanced Raman spectroscopy (SERS), rely on the ability of plasmonic nanoparticles to induce localized electromagnetic field enhancements in close proximity to the metallic surface. The possibility of achieving SERS signal enhancements high enough to enable sensitive identification of analytes down to the single molecule level depends on the presence of the so-called “hot spots”, which can be located at the vertices, edges, or crevices in isolated nanoparticles or at narrow junctions between assembled nanoparticles. In turn, the presence of finely tunable hot spots correlates to the possibility of applying SERS as a reliable spectroscopic technique in the analytical and biomedical fields. Our group has worked for several years on the implementation of SERS sensing substrates and imaging tags, in which gold nanostars have demonstrated to be excellent substrates. We have also shown that when these nanostructures are conformally coated with semiconductors such as TiO2 they can efficiently photocatalyze the evolution of hydrogen from water via near IR induced generation of hot electrons. However, for the realization of more quantitative approaches, and for a more reliable E-field manipulation, improved plasmonic platforms are necessary. For this reason, we have established a combined experimental and computational approach that has led us to synthesize by design highly monodispersed gold nanostars with localized surface plasmon resonances tunable between 600 and 2000 nm. We have measured their plasmonic response both at the single particle level (via EELS) and in ensemble averaged samples (UV-Vis and FT-IR spectroscopies), with excellent agreement with the theoretical predictions obtained with 3D finite element simulations, underscoring their importance as testbeds for the design and development of 3D colloidal antennas.
On: February 22, 2019 From: 10h00 To: 11h00View talk