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Seminar Series
Fast and sensitive detection of bacteria from dilute suspensions by
combining Electrokinetics and micro-Raman spectroscopy
David Liao
ABSTRACT
To prevent the spread of pathogens, fast and accurate detection methods for trace amounts of the target pathogen are crucial.
Established methods that test for the presence of biologically infectious agents in dilute concentrations traditionally require
cultivation to amplify the number of pathogens present. In this presentation, a method that combines micro-Raman spectroscopy
and electrokinetic forces to detect bacteria at dilute concentrations without cultivation is discussed. The method is characterized
by three key features, namely, accelerated transportation and focusing of bacteria to the detection surface by means of an electric
field, selective capture of the target microorganism using surface-immobilized antibodies, and sensitive detection of target
bacteria with micro-Raman spectroscopy. The electric field is created by an AC signal-driven planar, quadrupolar, gold
microelectrode array that has been photolithographically embedded in the detection surface. Using this method, detection of
Escherichia coli K12 (target microorganism) at concentrations as low as 102 bacteria/mL and within only a few minutes can be
reproducibly achieved from 50 L sample droplets.
Seminar Series
Development of an ion-exchanger membrane for PDMS-based microfluidic devices
Rio Festarini
ABSTRACT
The purpose of this research is to investigate a few potential methods to produce an ion-exchange membrane that can be
integrated directly into a polydimethylsiloxane (PDMS) Lab on a Chip or Micro Total Analysis System. The DuPont product
Nafion™ was chosen as the ion-exchange membrane, a copolymer with high conductivity to cations and suitable for many
applications such as electrolysis of water and the chlor-alkali process. Through the use of the inherent properties of PDMS, very
inexpensive sugar granulate can be used to make an inexpensive membrane mold which does not interfere with the PDMS
crosslinking process. After dissolving away this sacrificial mold material, Nafion™ is solidified in the irregular granulate holes.
Nafion™ in this membrane is restrained in the irregular shape of the PDMS openings. The outer structure of the membrane is
all PDMS and can be attached easily and securely to any PDMS build Lab on a Chip through reversible or irreversible
PDMS/PDMS bonding.
Seminar Series
Elemental Sulfur, a Source of Energy and Gypsum Production
Yasmine Hajar
ABSTRACT
Canadian sulfur production from bitumen and natural gas has been raising environmental concerns regarding storage of sulfur
in solid blocks. Long-term plans for handling, storing and using the sulfur are required. The proposed solution is to convert
sulfur to electrical energy and environmentally benign calcium sulfate (gypsum) by reacting it with a source of calcite through
the exothermic reaction:
S(s) + CaCO3(s) +3/2 O2 → CaSO4(s) + CO2(g) ΔH⁰=-621 kJ/mol
In this study, thermodynamic analysis of the proposed industrial-scale processes has shown the effect of changing the route
and conditions of the reaction on the electrical efficiency of the system. The suggested main route is to combust sulfur in a
turbine combined cycle, then react SO2 with calcite in a Flue Gas Desulfurization (FGD) system. At lab-scale, multiple set-ups
were designed and built to study the high-temperature reaction and the effects of changing reactant ratio and temperature on
sulfur conversion, in different gas conditions. The results were evaluated through thermogravimetric analysis and x-ray
diffraction.
Seminar Series
Encapsulation and Release of Oseltamivir Phosphate and Gemcitabine from Monoglyceride
Stabilized ‘Pickering’ Emulsions for Sustained Drug Delivery
Kurt Wood
ABSTRACT
The sustained release of small hydrophilic drugs such as oseltamivir phosphate (OP) and gemcitabine is a significant challenge
due to the rapid rate at which they are dispersed in tissue and bodily fluids. Encapsulation of these drugs in water-in-oil (W/O),
monoglyceride stabilized emulsions may present a possible solution to this challenge. OP has been successfully encapsulated
into a monoglyceride stabilized emulsion and a sustained release to an external aqueous phase has been demonstrated. This
approach has the key advantage of utilizing inherently biocompatible, renewable materials in its formulation. Additionally, the
monoglyceride stabilizer has been demonstrated to from pickering stabilized droplets which encapsulate the drug. Pickering
stabilization provides enhanced steric stability against droplet coalescence, and imparts an enhanced diffusional barrier to drug
release. During the course of this ongoing project, the emulsion formulation will be optimized to deliver the encapsulated drugs
at a therapeutic rate. The feasibility of converting the emulsion to a water-in-oil-in-water (W/O/W) double emulsion for reduced
viscosity will also be investigated.
Seminar Series
Delivery of Oseltamivir Phosphate and Gemcitabine from
Poly (D, L-Lactic-co-Glycolic Acid) for the Treatment of
Pancreatic Cancer
Stephanie Allison
ABSTRACT
Pancreatic cancer is the fourth leading cause of cancer death in Canada and has a five-year survival rate of only 6%. The low
survival rate is primarily due to late detection and resistance to chemotherapy. The current standard of care for unresectable
pancreatic cancer is gemcitabine (GEM), but less than 6% of patients exhibit a reduction in tumor size following treatment. Our
lab has identified neuraminidase 1 (Neu1) as a key player in growth factor activation, providing a novel therapeutic target for
the treatment of pancreatic cancer. Oseltamivir phosphate (OP) is a Neu1 inhibitor and has been shown to inhibit tumor growth
in RAG2xCγ double mutant mice. Implantable cylinders containing OP and GEM were developed using poly (D, L-lactic-coglycolic acid) as an encapsulation polymer, to enable drug delivery at the tumor site. The aim of the project is to develop a
method of delivering OP and GEM over an extended period of time and to test the efficacy of the released drugs in vitro with
the human pancreatic cancer cell line Panc1 and GEM-resistant Panc1.
Seminar Series
A New Optimization Model and a Customized Global Optimization Method for Design and
Operation of Natural Gas Production Networks under Uncertainty
Dan Li
ABSTRACT
The integrated design and operation problem for natural gas production networks is to determine the network design decisions,
platform pressures and the gas flows in operation to achieve the best expected profit, while meeting the customer demands and
product specifications. The existing methodologies either use an optimization model with limited details of the system or cannot
ensure a globally optimal solution. This research aims to develop an improved optimization model that describes more details
of the physical system. A reformulation of the proposed model exhibits a partially convex and block diagonal structure, and a
bi-level decomposition method is developed to exploit this problem structure for efficient global optimization. Case study results
of an industrial gas production system demonstrate the benefits of the proposed model and the optimization method.
Seminar Series
A New Robust Scenario Approach for Supply Chain Optimization under
Bounded Demand Uncertainty
Niaz Chowdhury
ABSTRACT
Supply Chain Optimization problem under uncertainty can be modeled as two stage optimization problem where first stage
decision variables are associated with design of facilities and second stage decision variables are associated with operation
of the supply chain network. Uncertainty in different parameter of supply chain network can be better dealt with robust scenario
formulation which works better than the classical scenario formulation by ensuring feasibility and better expected economic
performance. The most common uncertain parameter in supply chain network is demand and depending on the supply chain
network, the uncertainty region can be of different shape. The main purpose of this presentation is to propose a systematic way
to address any bounded uncertainty region in supply chain optimization. Any bounded uncertainty region can be divided into a
number of box uncertainty subregions, each associated with a scenario. Screening processes are applied to the uncertainty
subregions, leading to optimization problems with over-estimation and under-estimation of the original uncertainty region. When
the number of scenarios increases, the optimal objective values of the two optimization problems converge to a constant, which
is a good estimate of the true optimal value. Since the box uncertainty subregions are described by the infinity norm, the
optimization problems to be solved have constraints involving 1- norm, and these constraints can be transformed into linear
constraints. A supply chain network from DuPont will be used to demonstrate the effectiveness of the proposed approach.
Seminar Series
Geometric Based Estimation and Nonlinear PI Controller
for Dynamic Optimization Problem
Ehsan Moshksar
ABSTRACT
The subject of this talk is the minimization of an unknown but measurable cost function that is subject to unknown dynamics.
An extremum-seeking algorithm is proposed to solve the black-box optimization problem. The Lie derivatives of the convex
cost function with respect to nonlinear dynamics of the system are regarded as time-varying parameters. A new technique based
on the concept of almost invariant manifolds is proposed for the adaptive estimation of the time-varying parameters. A nonlinear
proportional-integral approach is then used to formulate the extremum-seeking controller. This approach is shown to avoid the
need for a time-scale separation in real-time optimization problem. The effectiveness of the proposed method is illustrated with
a simulation example.
Seminar Series
Observer design using potential based realizations
Ryan Bennett
ABSTRACT
This presentation considers observer design for nonlinear dynamical system which can be approximated by a dissipative
Hamiltonian realization. The design approach decomposes the system associated one-form of a given dynamical system over an
indeterminate or a pre-determined time-invariant metric using the Homotopy operator to generate exact (potential driven) and
anti-exact parts. Then the convexity of the potential system given by the exact part is assessed and a metric equation is proposed
which yields a Lyapunov function for the potential driven observer system. Applications of the method are then shown using
non-trivial (non-convergent) examples.