A new sub-nanosecond LED at 280 nm: application to protein fluorescence

McGuinness, Colin D.; Sagoo, Kulwinder; McLoskey, David; Birch, David J. S.

doi:10.1088/0957-0233/15/11/l02

Cited by 77 publications

(56 citation statements)

References 18 publications

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“…An AlGaN version of a pulsed light emitting diode working at 279 nm was used to excite Tyr (McGuiness et al, 2004) and fluorescence was detected at 315 nm. The pulse duration was ∼600 ps (fwhm) and repetition rate 1 MHz.…”

Section: Methodsmentioning

confidence: 99%

Early detection of amyloid aggregation using intrinsic fluorescence

Rolinski

Amaro

Birch

2010

Biosensors and Bioelectronics

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Section: Methodsmentioning

confidence: 99%

Early detection of amyloid aggregation using intrinsic fluorescence

Rolinski

Amaro

Birch

2010

Biosensors and Bioelectronics

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“…the decay model given by (5), with the I(t) part represented by eq. (1), has to be applied to the decays measured at the series of detection wavelengths for each step of aggregation.…”

Section: Fitted Parametersmentioning

confidence: 99%

Tyrosine Photophysics During the Early Stages of β-Amyloid Aggregation Leading to Alzheimer’s

Rolinski

Wellbrock

Birch

et al. 2015

J. Phys. Chem. Lett.

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We have monitored the formation of toxic β-amyloid oligomers leading to Alzheimer's disease by detecting changes in the fluorescence decay of intrinsic tyrosine. A new approach based on the non-Debye model of fluorescence kinetics resolves the complexity of the underlying photophysics. The gradual disappearance of nonmonotonic fluorescence decay rates, at the early stages of aggregation as larger, tighter-packed oligomers are formed, is interpreted in terms of tyrosine-peptide dielectric relaxation influencing the decay. The results demonstrate the potential for a new type of fluorescence lifetime sensing based on dual excited-state/dielectric relaxation, with application across a broad range of biological molecules. The results also reconcile previously conflicting models of protein intrinsic fluorescence decay based on rotamers or dielectric relaxation by illustrating conditions under which both are manifest.

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“…The relatively long and random jitter associated with the timing of the spark can also lead to a significant proportion of 'missed' acquisitions which, combined with the long recharge time of the high-voltage electronics, may significantly lengthen the experimental work. The LED technology has advanced rapidly, and can now provide low-jitter sub-nanosecond [14] and high-frequency light pulses [15]. However, the energy output of high-power LEDs is still insufficient to enable blur-free microscopic imaging of high-speed sprays.…”

Section: Introductionmentioning

confidence: 99%

Microscopic imaging of the initial stage of diesel spray formation

Crua

Heikal

Gold³

2015

Fuel

119

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Detailed measurements of near-nozzle spray formation are essential to better understand and predict the physical processes involved in diesel fuel atomisation. We used long-range microscopy to investigate the primary atomisation of diesel, biodiesel and kerosene fuels in the near-nozzle region, both at atmospheric and realistic engine conditions. High spatial and temporal resolutions allowed a detailed observation of the very emergence of fuel from the nozzle orifice. The fluid that first exited the nozzle resembled mushroom-like structures, as occasionally reported by other researchers for atmospheric conditions, with evidence of interfacial shearing instabilities and stagnation points. We captured the dynamics of this phenomenon using an ultra-fast framing camera with frame rates up to 5 million images per second, and identified these structures as residual fluid trapped in the orifice between injections. The residual fluid has an internal vortex ring motion which results in a slipstream effect that can propel a microscopic ligament of liquid fuel ahead. We showed that this mechanism is not limited to laboratory setups, and that it occurs for diesel fuels injected at engine-like conditions with production injectors. Our findings confirm that fuel can remain trapped in the injector holes after the end of injection. Although we could not measure the hydrocarbon content of the trapped vapourised fluid, we observed that its density was lower than that of the liquid fuel, but higher than that of the in-cylinder gas. We conclude that high-fidelity numerical models should not assume in their initial conditions that the sac and orifices of fuel injectors are filled with in-cylinder gas. Instead, our observations suggest that the nozzle holes should be considered partially filled with a dense fluid

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A new sub-nanosecond LED at 280 nm: application to protein fluorescence

Cited by 77 publications

References 18 publications

Early detection of amyloid aggregation using intrinsic fluorescence

Early detection of amyloid aggregation using intrinsic fluorescence

Tyrosine Photophysics During the Early Stages of β-Amyloid Aggregation Leading to Alzheimer’s

Microscopic imaging of the initial stage of diesel spray formation

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