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Thursday 19 December
Perlman Chemical Sciences Building 03:00
Chemical and Biological Physics Guest Seminar Prof. Aharon Brodutch [Info]

Chemical and Biological Physics Guest Seminar

Quantum theory has been incredibly successful at explaining known phenomena and making new predictions that have led to some of the most important scientific and technological breakthroughs in the past century. Quantum computers are arguably the boldest prediction of the theory, but the level of control required to build them is extremely challenging. The requirements for building universal fault tolerant quantum computers (i.e computers that can run any quantum algorithm with high accuracy) are far beyond current capabilities, but less powerful (intermediate) quantum machines are already available, with some accessible online. The minimal requirements for such intermediate machines to significantly outperform ordinary (classical) computers is currently an open area of research. One approach to study the capabilities of intermediate quantum machines, is to study how small subsystems become correlated (and entangled) during a computation. I will provide an overview of work in this direction with some surprising results on the possible role of quantum entanglement. These results provide new insights into quantum theory and quantum technology. University of Toronto
Tuesday 07 January
Helen and Milton A. Kimmelman Building 11:00
A hydrogen-bonded framework toolkit for molecular structure determination Prof. Michael D. Ward [Info]

A hydrogen-bonded framework toolkit for molecular structure determination

Single crystal X-ray diffraction is arguably the most definitive method for molecular structure determination, but the inability to grow suitable single crystals can frustrate conventional X-ray diffraction analysis. Building on a prolonged examination of hydrogen-bonded frameworks and inclusion compounds derived from guanidinium organosulfonates, we have devised an approach to molecular structure determination that relies on a versatile toolkit of these host frameworks, which form crystalline inclusion compounds with target guest molecules in a single-step crystallization. This approach complements the so-called crystalline sponge method that relies on diffusion of the target into the cages of a metal-organic framework, while circumventing many of its challenges. The peculiar properties of the host frameworks enable rapid stoichiometric inclusion of a wide range of target molecules with full occupancy, typically without disorder and accompanying solvent, affording well-refined structures. Moreover, anomalous scattering by the framework sulfur atoms enables reliable assignment of absolute configuration of stereogenic centers. An ever-expanding library of organosulfonates provides a toolkit of frameworks for capturing specific target molecules for their structure determination. This presentation will describe examples of this approach to structure determination, preceded by an account of the unusual properties and resilience of these hydrogen-bonded frameworks, their substantial diversity of framework architectures, and their utility in other applications. Department of Chemistry and Molecular Design Institute, New York University
Sunday 12 January
Perlman Chemical Sciences Building 02:00
Chemical and Biological Physics Guest Seminar Prof. Peter Hamm [Info]

Chemical and Biological Physics Guest Seminar

U. of Zurich
Tuesday 28 January
Perlman Chemical Sciences Building 11:00
Chemical and Biological Physics Dept Seminar Dr Rinat Ankri [Info]

Chemical and Biological Physics Dept Seminar

Biomolecular imaging at the preclinical stage is an essential tool in various biomedical research areas such as immunology, oncology or neurology. Among all modalities available to date, optical imaging techniques play a central role, while fluorescence, in particular in the NIR region of the spectrum, provides high sensitivity and high specificity with relatively cheap instrumentation. Several whole-body optical pre-clinical NIR imaging systems are commercially available. Instruments using continuous wave (CW or time-independent) illumination allow basic small animal imaging at low cost. However, CW techniques cannot provide fluorescence lifetime contrast, which allows to probe the microenvironment and affords an increased multiplexing power. In the first part of my talk I will introduce our single photon, time-gated, phasor-based fluorescence lifetime Imaging method which circumvents limitations of conventional techniques in speed, specificity and ease of use, using fluorescent lifetime as the main contrast mechanism. In the second part of my talk I will present the tracking and multiplexing of two different cell populations, based on their different lifetimes (following their fluorescent dyes-loading). Despite major advantages of optical based NIR imaging, the reason that NIR imagers are not clinically used, is that only very few such fluorescent molecules absorb and emit in the NIR (or in the shortwave infrared, SWIR region), and even fewer have favorable biological properties (and FDA approval). I will introduce small lung cancer and dendritic cells tracking using small polyethylene glycol/phosphatidylethanolamine (PEG–PE) micelles loaded with NIR dyes (using commercial dyes as well as dyes synthesized in Prof. Sletten’s lab, UCLA Chemistry Dept.). Micelles’ endocytosis into cells affords efficient loading and exhibits strong bio stability, enabling to track the loaded cells for several days using these formulations, even though dyes were diluted by cells division (leading to reduced dye concentration within the dividing cells). Moreover, fluorescent lifetime contrast (achieved through our time-gated imaging method), significantly improved these cells detection. These advances in NIR fluorescence based imaging open up new avenues toward NIR and SWIR imaging for biomedical applications, such as tracking and monitoring cells during immunotherapy and/or drug delivery (treatment monitoring) for various types of disease. Postdoctoral Fellow, UCLA, CA