Light Beating Spectroscopy

Cummins, H. Z.

doi:10.1007/978-1-4615-8906-8_6

Cited by 139 publications

(221 citation statements)

References 4 publications

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“…This seems surprising, at first, since scattering intensity is heavily weighted towards larger aggregates and, to a first approximation, measures the weight-average of aggregates. 28 The particle size distributions derived from simultaneous DLS measurements suggest how the SLS signal might be reporting changes to the number-and not to the weightaverage of the aggregates. Following nucleation, changes in the particle size distribution measured with DLS were dominated by increases in the peak area while the average hydrodynamic radii changed surprisingly little.…”

Section: Structure-specific Tht Responses During Oligomer-free Vs Olmentioning

confidence: 99%

Structural fingerprints and their evolution during oligomeric vs. oligomer-free amyloid fibril growth

Foley

Hill

Miti

et al. 2013

The Journal of Chemical Physics

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Deposits of fibrils formed by disease-specific proteins are the molecular hallmark of such diverse human disorders as Alzheimer's disease, type II diabetes, or rheumatoid arthritis. Amyloid fibril formation by structurally and functionally unrelated proteins exhibits many generic characteristics, most prominently the cross β-sheet structure of their mature fibrils. At the same time, amyloid formation tends to proceed along one of two separate assembly pathways yielding either stiff monomeric filaments or globular oligomers and curvilinear protofibrils. Given the focus on oligomers as major toxic species, the very existence of an oligomer-free assembly pathway is significant. Little is known, though, about the structure of the various intermediates emerging along different pathways and whether the pathways converge towards a common or distinct fibril structures. Using infrared spectroscopy we probed the structural evolution of intermediates and late-stage fibrils formed during in vitro lysozyme amyloid assembly along an oligomeric and oligomer-free pathway. Infrared spectroscopy confirmed that both pathways produced amyloid-specific β-sheet peaks, but at pathwayspecific wavenumbers. We further found that the amyloid-specific dye thioflavin T responded to all intermediates along either pathway. The relative amplitudes of thioflavin T fluorescence responses displayed pathway-specific differences and could be utilized for monitoring the structural evolution of intermediates. Pathway-specific structural features obtained from infrared spectroscopy and Thioflavin T responses were identical for fibrils grown at highly acidic or at physiological pH values and showed no discernible effects of protein hydrolysis. Our results suggest that late-stage fibrils formed along either pathway are amyloidogenic in nature, but have distinguishable structural fingerprints. These pathway-specific fingerprints emerge during the earliest aggregation events and persist throughout the entire cascade of aggregation intermediates formed along each pathway. © 2013 AIP Publishing LLC. [http://dx

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Section: Structure-specific Tht Responses During Oligomer-free Vs Olmentioning

confidence: 99%

Structural fingerprints and their evolution during oligomeric vs. oligomer-free amyloid fibril growth

Foley

Hill

Miti

et al. 2013

The Journal of Chemical Physics

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“…(Cummins & Swinney, 1970;Cummins & Pike, 1974;Chu, 1974;Berne & Pecora, 1975). In this method, a small volume of a suspension of identical (and spherically symmetrical) colloidal particles containing v particles is illuminated by a collimated beam of coherent (laser) light (with wave vector k ( ), and the intensity of scattered light (with wave vector k s ) measured at a certain angle 8 (Fig.…”

Section: The Diffusivity Of Colloidal Spheresmentioning

confidence: 99%

“…For scatterers undergoing translational diffusion (Brownian motion) characterized by their diffusivity D, carrying out ensemble average and sum (Cummins & Swinney, 1970) yields:…”

Section: « ( T ) = -S (17)mentioning

confidence: 99%

Experimental methods for investigating protein adsorption kinetics at surfaces

Ramsden¹

1994

Quart. Rev. Biophys.

177

131

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The adsorption of proteins at the solid-liquid interface is a process of fundamental importance in nature. Extensive reviews (MacRitchie, 1978; Andrade & Hlady, 1986; Norde, 1986) testify to the strong interest which has been shown in the problem during the past few decades. Norde & Lyklema (1978) have rightly pointed out that protein adsorption is scientifically intriguing; the phenomenology is complicated and includes many presently apparently irreconcilable observations.

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“…became obsolete because of their insufficient frequency resolution; standard radio-frequency (RF) characterization techniques were then transposed to the optical domain [8]. Today, with state-of-the-art lasers having linewidths below a single hertz [9] and most commercial lasers having linewidths below 100 MHz, these RF characterization techniques are ubiquitous.…”

Section: Introductionmentioning

confidence: 99%

Passive coherent discriminator using phase diversity for the simultaneous measurement of frequency noise and intensity noise of a continuous-wave laser

et al. 2016

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The frequency noise and intensity noise of a laser set the performance limits in many modern photonics applications and, consequently, must often be characterized. As lasers continue to improve, the measurement of these noises however becomes increasingly challenging. Current approaches for the characterization of very high-performance lasers often call for a second laser with equal or higher performance to the one that is to be measured, an incoherent interferometer having an extremely long delay-arm, or an interferometer that relies on an active device. These instrumental features can be impractical or problematic under certain experimental conditions. As an alternative, this paper presents an entirely passive coherent interferometer that employs an optical 90° hybrid coupler to perform in-phase and quadrature detection. We demonstrate the technique by measuring the frequency noise power spectral density of a highly-stable 192 THz (1560 nm) fiber laser over five frequency decades. Simultaneously, we are able to measure its relative intensity noise power spectral density and characterize the correlation between its amplitude noise and phase noise. We correct some common misconceptions through a detailed theoretical analysis and demonstrate the necessity to account for normal imperfections of the optical 90° hybrid coupler. We finally conclude that this passive coherent discriminator is suitable for reliable and simple noise characterization of highly-stable lasers, with bandwidth and dynamic range benefits but susceptibility to additive noise contamination.

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Light Beating Spectroscopy

Cited by 139 publications

References 4 publications

Structural fingerprints and their evolution during oligomeric vs. oligomer-free amyloid fibril growth

Structural fingerprints and their evolution during oligomeric vs. oligomer-free amyloid fibril growth

Experimental methods for investigating protein adsorption kinetics at surfaces

Passive coherent discriminator using phase diversity for the simultaneous measurement of frequency noise and intensity noise of a continuous-wave laser

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