Speakers
	Dr. Erin Calipari Vanderbilt University Dr. Calipari received her PhD in Neuroscience in 2013 in the laboratory of Dr. Sara Jones at Wake Forest University School of Medicine where she studied how self-administered drugs altered dopaminergic function to drive addictive behaviors. She then went on to complete her postdoctoral training with Dr. Eric Nestler at Icahn School of Medicine at Mount Sinai, where she used circuit probing techniques to understand the temporally specific neural signals that underlie motivation and reward learning. She is currently an Assistant Professor at Vanderbilt University in the Department of Pharmacology. Her independent work seeks to characterize and modulate the precise circuits in the brain that underlie both adaptive and maladaptive processes in reward, motivation, and associative learning. Group Page
	Dr. Tim Harris Johns Hopkins University Timothy Harris is a research professor in the Department of Biomedical Engineering. He leads the Applied Physics and Instrumentation Group at the HHMI Janelia Research Campus, and is the originator of the project that produced the Neuropixels Si probe for extracellular recording in animals, mostly mice, and rats. He shares his time between Janelia and Johns Hopkins and is working on projects to enable recording 10-20,000 neurons in rodents and 30-50,000 neurons in non-human primates, as well as stimulate with high resolution. He received a BS in Chemistry at California Polytechnical State University, San Luis Obispo, and a PhD in Analytical Chemistry at Purdue University. Group Page
	Dr. Elizabeth Hillman Columbia University Elizabeth Hillman is professor of biomedical engineering and radiology at Columbia University and a member of the Mortimer B. Zuckerman Mind Brain Behavior Institute and Kavli Institute for Brain Science at Columbia. Hillman received her undergraduate degree in physics and Ph.D. in medical physics and bioengineering at University College London and completed post-doctoral training at Massachusetts General Hospital/Harvard Medical School. In 2006, Hillman moved to Columbia University, founding the Laboratory for Functional Optical Imaging. Hillman’s research program focuses on the development and application of optical imaging and microscopy technologies to capture functional dynamics in the living brain. Most recently, she developed swept confocally aligned planar excitation (SCAPE) microscopy, a technique capable of very high speed volumetric imaging of neural activity in behaving organisms such as adult and larval Drosophila, zebrafish, C. elegans and the rodent brain. Hillman’s research program also includes exploring the interrelation between neural activity and blood flow in the brain, as the basis for signals detected by functional magnetic resonance imaging (fMRI). Hillman is a fellow of the Optical Society of America (OSA), the society of photo-optical instrumentation (SPIE) and the American Institute for Medical and Biological Engineering (AIMBE). She has received the OSA Adolf Lomb Medal for contributions to optics, as well as early career awards from the Wallace Coulter Foundation, National Science Foundation and Human Frontier Science Program. Group Page
	Dr. Baljit Khakh University of California, Los Angeles Baljit Khakh completed his Ph.D. at the University of Cambridge in the laboratory of Patrick PA Humphrey. He completed postdoctoral fellowships in the laboratory of Graeme Henderson at the University of Bristol, and then in the laboratory of Henry A. Lester and Norman Davidson at California Institute of Technology. In 2001, Khakh became Group Leader at the MRC Laboratory of Molecular Biology in Cambridge, and in 2006 he moved to the University of California, Los Angeles where he is Professor of Physiology and Neurobiology. Khakh’s work has been recognized, including with the NIH Director's Pioneer Award, the Paul G. Allen Distinguished Investigator Award, and the Outstanding Investigator Award (R35) from NINDS. Group Page

2022 Naff Symposium Committee

Dr. Chris Richards - Chair

**CANCELLED**

Marco Bonizzoni

Department of Chemistry and Biochemistry, The University of Alabama, Tuscaloosa, AL, USA.
Alabama Water Institute, The University of Alabama, Tuscaloosa, AL, USA.

E-mail: marco.bonizzoni@ua.edu

Abstract: Artificial supramolecular receptors often rely on weak intermolecular interactions for their chemical recognition properties, so they may struggle to work in competitive media, chief among 

which are water solutions. However, aqueous media are very important in analytical, environmental, and biomedical applications, so it is valuable to adapt our supramolecular tools to them. With the right tools, even the weakest noncovalent interactions can be pressed into service in aqueous media. We have been using water-soluble polymers (e.g. dendrimers, hydrogels, conjugated polymers) as scaffolds to build multivalent supramolecular sensors that take advantage of the large number of interactions and of the preorganization of receptor sites afforded by such scaffolds, resulting in improved affinity in buffered aqueous solutions near neutral pH. We have successfully built systems for the detection of interesting guest families, including carboxylate anions, simple saccharides, heavy metal cations, and polycyclic aromatic hydrocarbons. These are examples of a general approach with two key advantages. On the one hand, installing known receptor chemistry on a polymer scaffold affords a modular approach to multivalency with minimal design and synthesis effort. This improves the apparent strength of weaker interactions and allows them to overcome desolvation costs in water. On the other hand, water-soluble macromolecular scaffolds impart solubility to water-incompatible receptor families.

This simple approach is particularly valuable when designing chemical fingerprinting systems (sometimes referred to as an “electronic nose” or “tongue”) that typically require many different receptors, each one poorly selective, and recovers selectivity from judicious interpretation of the ensemble response.

**CANCELLED**

Abstract: Secondary metabolites are organic compounds produced by an organism for reasons other than growth and development. In plants, secondary metabolites generally act as defense agents produced to deter predators and inhibit other competitive species. For humans, these compounds can often have a beneficial effect and are pursued and utilized as natural pharmaceuticals. The development of sensitive, high-throughput analytical screening methods for plant derived metabolites is crucial for natural pharmaceutical product discovery and plant metabolomic profiling. Here, metabolomic profiling methods were developed using a microfluidic capillary zone electrophoresis device and evaluated against traditional separation approaches. An alkaloid screening assay was constructed to analyze transgenic mutant plant extracts for novel metabolites. Putatively identified novel features were detected, elucidated, and then isolated and purified for pharmaceutical evaluation. Additionally, methods for the analysis of polyphenolic plant-derived secondary metabolites, such as cannabinoids, were also developed and evaluated. In this case, the occurrence of cross-instrumental variation was addressed, given the tight legal restrictions regarding commercialization the products in question. Lastly, the microfluidic CZE-MS methods were further applied for both primary and secondary metabolite profiling in a DMPK assay. This assay was developed to inclusively monitor metabolic changes as a response to varying concentrations of a therapeutic in circulation. The metabolomic methods developed and evaluated in this work displayed high sensitivity, efficiency, and accuracy and can be utilized across a wide variety of applications.

Attend the seminar here. Password 618011.

Abstract: Small-molecule organic materials are of increasing interest for electronic and photonic devices due to their solution processability and tunability, allowing devices to be fabricated at low temperature on flexible substrates and offering utility in specialized applications. This tunability is the result of functionalization through careful synthetic strategy to influence both material properties and solid-state arrangement, both crucial variables in device applications. Functionalization of a core molecule with various substituents allows the fine-tuning of optical and electronic properties, and functionalization with solubilizing groups allows some degree of control over the solid-state order, or crystal packing. These combinations of core chromophores with varying substituents are systematically evaluated to develop structure-function relationships that can be applied to numerous applications. In this work, heteroacenes are investigated for singlet fission and triplet harvesting, with known crystal engineering strategies applied to optimize crystal packing and maximize relevant solid-state interactions. Further, a class of antiaromatic compounds are investigated using the same approaches to build up structure-function relationships and provide insight into the properties of a relatively understudied core molecule.

Attend the seminar here.

Professor Andrew Gewirth

The University of Illinois at Urbana-Champaign

Understanding and Controlling Electrochemistry for Electrolyzers and Batteries

Abstract:

This talk addresses the electrochemical reactivity associated with electrolyzers and batteries.  Relevant to electrolyzers we show that electrodeposition of CuAg or CuSn alloy films under suitable conditions yields high surface area catalysts for the active and selective electroreduction of CO₂ to multi-carbon hydrocarbons and oxygenates.  Alloy films containing Sn exhibit greater efficiency for CO production relative to either Cu along or CuAg at low overpotentials.   In-situ Raman and electroanalysis studies suggest the origin of the high selectivity towards C₂ products to be a combined effect of the diminished stabilization of the Cu₂O overlayer and the optimal availability of the CO intermediate due to the Ag or Sn incorporated in the alloy.  Sn-containing films exhibit less Cu₂O relative to either the Ag-containing or neat Cu films, likely due to the increased oxophilicity of the admixed Sn.  Incorporation of a polymer into the Cu electrodeposit leads to very active CO₂ reduction electrocatalysis due to pH changes at the electrified interface.  Vibrational spectroscopy is used to evaluate the pH at the interface during electrolyzer operation.

Relevant to batteries, we discuss solid electrolytes (SEs) which have become a practical option for lithium ion and lithium metal batteries due to their improved safety over commercially available ionic liquids. The most promising of the SEs are the thiophosphates whose excellent ionic conductivities at room temperature approach those of commercially-utilized electrolytes. Hybrid solid-liquid electrolytes exhibit higher ionic conductivities than their bare solid electrolyte counterparts due to decreased grain boundary resistance, enhanced interfacial contact with electrodes, and decreased degradation at the interface. Spectroscopic and structural studies on these latter materials lead to new formulations and artificial SEI materials exhibiting advantageous properties.

Host: ECS UK chapter

Professor Marc T. M. Koper

Leiden University, Netherlands

Advances and challenges in understanding the electrocatalytic conversion of carbon dioxide to fuels

Abstract:

The electrocatalytic reduction of carbon dioxide is a promising approach for storing (excess) renewable electricity as chemicalenergy in fuels. Here, I will discuss recent advances and challenges in the understanding of electrochemical CO2 reduction. I will summarize existing models for the initial activation of CO2 on the electrocatalyst and their importance for understanding selectivity. Carbon–carbon bond formation is also a key mechanistic step in CO2 electroreduction to high-density and high-value fuels. I will show that both the initial CO2 activation and C–C bond formation are influenced by an intricate interplay between surface structure (both on the nano- and on the mesoscale), electrolyte effects (pH, buffer strength, ion effects) and mass transport conditions. This complex interplay is currently still far from being completely understood.

Y.Y.Birdja, E.Perez-Gallent, M.C.Figueiredo, A.J.Göttle, F.Calle-Vallejo, M.T.M.Koper, Nature Energy 4 (2019) 732-745

Host: ECS UK chapter

Abstract: The Resistant Nodulation Division (RND) super family member, tripartite AcrA-AcrB-TolC efflux pump is a major contributor in conferring multidrug-resistance in Escherichia coli. The structure of the pump complex, drug translocation by functional rotation mechanism has been widely studied through crosslinking studies, crystallography, and Cryo-EM efforts. Furthermore, the ClpXP system has been identified as important in degrading ssrA tagged AcrB. Despite all this data, the dynamics of assembly process of the pump and AcrB during functional rotation in the process of drug efflux, the proteases in degrading AcrB remains poorly understood. The focus of my thesis is understanding pump assembly process, dynamics of AcrB in functional rotation mechanism, and identifying the proteases that degrade ssrA tagged AcrB. First, I used disulfide bond crosslinking, minimum inhibitory concentration (MIC) and EtBr efflux assay in studying the importance of the relative flexibility at the inter-subunit interface by introducing 6 inter-subunit disulfide bonds into the periplasmic domain of AcrB using site directed mutagenesis. Based on MIC the double Cys mutants tested led to equal or higher susceptibility to AcrB substrates compared to their corresponding single mutants. EtBr accumulation assays was conducted utilizing DTT as the reducing agent. In two cases, the activities of the double Cys-mutants were partially restored by DTT reduction, confirming the importance of relative movement in the respective location for function. In the second project, I tested the effect of over-expressing functionally defective pump components in wild type E. coli cells to probe the pump assembly process. Incorporation of defective component is expected to reduce the efflux efficiency of the complex and leading to the so called “dominant negative” effect. We examined two groups of mutants defective in different aspects and found that none of them demonstrated the expected dominant negative effect, even at concentrations many folds higher than their genomic counterpart. Based on the data the assembly of the AcrAB-TolC complex appears to have a proof-read mechanism that effectively eliminated the formation of futile pump complex. Moreover, I utilized a novel tool- transposons library creation in studying the possible other proteases contribute to degradation of the AcrB-ssrA. The next generation sequencing identified already known ClpXP gene and MIC and western blot analysis confirmed the results. These, findings provide new insights to the dynamics of the AcrAB-TolC efflux pump in E. coli.  Key words: multidrug efflux pump, AcrB, assembly, disulfide, conformational changes, ssrA.

Join the seminar at

 https://uky.zoom.us/j/88673605310