Dr. Pengxiang Si November 20, 2020 @ 1 pm.

Abstract

Polyurethanes (PUs) are a class of versatile polymers; their structure and morphology can be readily tailored to exhibit various mechanical, physical, chemical and biological properties. PUs have been employed in a variety of industrial applications including foams, coatings, textiles, machinery, sporting, transportation, vehicles and construction. Water-based PU was developed to reduce the usage of volatile organic compounds (VOCs) in the synthesis of conventional solvent based PU, and exhibits advantages of superior material properties (e.g. flexibility, stretchability, elasticity, mechanical strength), processability (e.g. 3D printing, inkjet printing, screen printing, spray coating, molding) and sustainability (e.g. low VOCs, degradable). Water-based PU combines the superior mechanical properties of PU with the excellent stability of colloids. The current research trend of PU is shifting from traditional industrial applications to state-of-the-art fields such as soft and wearable electronics, energy storage devices, biosensors, actuators, photovoltaic devices and stimuli-responsive materials. Due to the existence of a variety of functional groups such as urethane, aliphatic or aromatic hydrocarbons, esters, ethers, amides and urea, water-based PU can be physically or chemically incorporated with functional materials to form PU colloidal composites towards various applications.

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Remi Casier December 3, 2020 @ 1pm

The Hierarchy of Protein Folding

Abstract

Proteins are biological macromolecules composed of linear polypeptide chains. Often, a specific three-dimensional arrangement of the constituting polypeptide chains is required to provide the protein a biological function. Despite all the advancements in protein science, a simple, yet fundamental question remains: How do proteins fold so quickly? A polypeptide chain has near infinite conformational space, yet many proteins are capable of rapidly navigating from a structureless state to their native conformation on the order of milliseconds to seconds. Therefore, it is clear that proteins cannot exhaustively probe their entire conformational space, and instead must somehow explore a more limited conformational space as they fold.

This presentation will provide an introduction to the concepts involved in protein folding. It will cover the underlying physical forces governing folding, the experimental evidence used to understand the folding behavior of proteins on a macroscopic and microscopic scale, and how the microscopic behavior of proteins can circumvent the time-scale folding problem.

Biography

Remi Casier obtained his BSc in honours chemistry in 2013 followed by his MSc in polymer chemistry in 2015 from the University of Waterloo. Under the supervision of Prof. Jean Duhamel, Remi is currently pursuing his PhD in polymer science. Currently, his research focuses on using advanced fluorescence techniques to probe the conformational state and internal dynamics of polypeptides in solution in order to provide insight to the dynamic behavior of proteins.  

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