Jason Wen Lau Lee

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We model oligomers of the Alzheimer's amyloid β-peptide Aβ(1-42) in an implicit membrane to obtain insight into the mechanism of amyloid toxicity. It has been suggested that Aβ oligomers are the toxic species, causing membrane disruption in neuronal cells due to pore formation. We use basin-hopping global optimization to identify the most stable structures(More)
A new technique for studying surface photochemistry has been developed using an ion imaging time-of-flight mass spectrometer in conjunction with a fast camera capable of multimass imaging. This technique, called pixel imaging mass spectrometry (PImMS), has been applied to the study of butanone photooxidation on TiO2(110). In agreement with previous studies(More)
By integrating a velocity-map imaging lens and position sensitive detector into an electron-impact time-of-flight mass spectrometer, it becomes possible to record ion kinetic energy release (KER) distributions for each fragment ion alongside the time-of-flight mass spectrum. The KER distributions allow ions of identical mass-to-charge ratio to be(More)
We present the first multimass velocity-map imaging data acquired using a new ultrafast camera designed for time-resolved particle imaging. The PImMS (Pixel Imaging Mass Spectrometry) sensor allows particle events to be imaged with time resolution as high as 25 ns over data acquisition times of more than 100 μs. In photofragment imaging studies, this allows(More)
The Pixel Imaging Mass Spectrometry (PImMS) camera is used in proof-of-principle three-dimensional imaging experiments on the photodissociation of carbonyl sulfide and ethyl iodide at wavelengths around 230 nm and 245 nm, respectively. Coupling the PImMS camera with DC-sliced velocity-map imaging allows the complete three-dimensional Newton sphere of(More)
In this paper, we present an enhanced virtual observation therapy (VOT) system to address challenges in medication adherence and the current observed therapy approach. The original approach requires both patient and healthcare worker to be physically collocated, which has several technical and practical challenges. Therefore, we developed a system that(More)
Imaging mass spectrometry is a powerful technique that allows chemical information to be correlated to a spatial coordinate on a sample. By using stigmatic ion microscopy, in conjunction with fast cameras, multiple ion masses can be imaged within a single experimental cycle. This means that fewer laser shots and acquisition cycles are required to obtain a(More)
Atmospheric aerosol particles are important in many atmospheric processes such as: light scattering, light absorption, and cloud formation. Oxidation reactions continuously change the chemical composition of aerosol particles, especially the organic mass component, which is often the dominant fraction. These ageing processes are poorly understood but are(More)
Accurate ionization cross-sections for DNA and RNA constituents in the condensed or aqueous phase are important parameters for models simulating radiation damage to genetic material in living cells. In this work, absolute gas-phase electron total ionization cross-sections (TICSs) have been measured for a series of six aromatic and eight non-aromatic cyclic(More)
Fiber-loop cavity ring-down spectroscopy (CRDS) is a highly sensitive spectroscopic absorption technique which has shown considerable promise for the analysis of small-volume liquid samples. We have developed a new light coupling method for fiber-loop CRDS, which overcomes two disadvantages of the technique: low efficiency light coupling into the cavity and(More)