ORCID Profile
0000-0003-4135-8079
Current Organisation
University of California, Irvine
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Publisher: IOP Publishing
Date: 13-06-2013
Publisher: OSA
Date: 2017
Publisher: Elsevier BV
Date: 09-2017
DOI: 10.1016/J.EJCB.2017.07.001
Abstract: We describe the general occurrence in animal cells of elastic components ("tethers") that connect in idual chromosomes moving to opposite poles during anaphase. Tethers, originally described in crane-fly spermatocytes, exert force on chromosome arms opposite to the direction the anaphase chromosomes move. We show that they exist in a broad range of animal cells. Thus tethers are previously unrecognised components of general mitotic mechanisms that exert force on chromosomes and they need to be accounted for in general models of mitosis in terms of forces on chromosomes and in terms of what their roles might be.
Publisher: Optica Publishing Group
Date: 25-11-2009
DOI: 10.1364/OE.17.022718
Publisher: IOP Publishing
Date: 12-05-2016
Publisher: Springer Science and Business Media LLC
Date: 02-05-2013
DOI: 10.1038/SREP01759
Publisher: IOP Publishing
Date: 04-03-2011
Publisher: Springer Science and Business Media LLC
Date: 20-04-2017
DOI: 10.1038/SREP46480
Abstract: The ability to successfully fertilize ova relies upon the swimming ability of spermatozoa. Both in humans and in animals, sperm motility has been used as a metric for the viability of semen s les. Recently, several studies have examined the efficacy of low dosage red light exposure for cellular repair and increasing sperm motility. Of prime importance to the practical application of this technique is the absence of DNA damage caused by radiation exposure. In this study, we examine the effect of 633 nm coherent, red laser light on sperm motility using a novel wavelet-based algorithm that allows for direct measurement of curvilinear velocity under red light illumination. This new algorithm gives results comparable to the standard computer-assisted sperm analysis (CASA) system. We then assess the safety of red light treatment of sperm by analyzing, (1) the levels of double-strand breaks in the DNA, and (2) oxidative damage in the sperm DNA. The results demonstrate that for the parameters used there are insignificant differences in oxidative DNA damage as a result of irradiation.
Publisher: Shanghai Institute of Optics and Fine Mechanics
Date: 2017
Publisher: Elsevier
Date: 2017
Publisher: OSA
Date: 2019
Publisher: OSA
Date: 2010
Publisher: OSA
Date: 2017
Publisher: Springer Science and Business Media LLC
Date: 25-06-2015
DOI: 10.1038/SREP11501
Abstract: Optogenetics uses light to control and observe the activity of neurons, often using a focused laser beam. As brain tissue is a scattering medium, beams are distorted and spread with propagation through neural tissue and the beam’s degradation has important implications in optogenetic experiments. To address this, we present an analysis of scattering and loss of intensity of focused laser beams at different depths within the brains of zebrafish larvae. Our experimental set-up uses a 488 nm laser and a spatial light modulator to focus a diffraction-limited spot of light within the brain. We use a combination of experimental measurements of back-scattered light in live larvae and computational modelling of the scattering to determine the spatial distribution of light. Modelling is performed using the Monte Carlo method, supported by generalised Lorenz–Mie theory in the single-scattering approximation. Scattering in areas rich in cell bodies is compared to that of regions of neuropil to identify the distinct and dramatic contributions that cell nuclei make to scattering. We demonstrate the feasibility of illuminating in idual neurons, even in nucleus-rich areas, at depths beyond 100 μm using a spatial light modulator in combination with a standard laser and microscope optics.
Publisher: IOP Publishing
Date: 04-03-2011
Publisher: The Optical Society
Date: 15-11-2017
DOI: 10.1364/OL.42.004772
Publisher: Springer Science and Business Media LLC
Date: 09-05-2016
DOI: 10.1038/LSA.2016.158
Publisher: SPIE-Intl Soc Optical Eng
Date: 13-02-2015
Publisher: The Optical Society
Date: 23-08-2017
DOI: 10.1364/BOE.8.004200
Publisher: Wiley
Date: 13-01-2015
DOI: 10.1002/JEMT.22463
Publisher: Optica Publishing Group
Date: 11-06-2021
DOI: 10.1364/BOE.427693
Abstract: In this paper, we propose a new system for studying cellular injury. The system is a biophotonic work station that can generate Laser-Induced Shockwave (LIS) in the cell culture medium combined with a Quantitative Phase Microscope (QPM), enabling the real-time measurement of intracellular dynamics and quantitative changes in cellular thickness during the damage and recovery processes. In addition, the system is capable of Phase Contrast (PhC) and Differential Interference Contrast (DIC) microscopy. Our studies showed that QPM allows us to discern changes that otherwise would be unnoticeable or difficult to detect using phase or DIC imaging. As one application, this system enables the study of traumatic brain injury in vitro. Astrocytes are the most numerous cells in the central nervous system (CNS) and have been shown to play a role in the repair of damaged neuronal tissue. In this study, we use LIS to create a precise mechanical force in the culture medium at a controlled distance from astrocytes and measure the quantitative changes, in order of nanometers, in cell thickness. Experiments were performed in different cell culture media in order to evaluate the reproducibility of the experimental method.
Publisher: OSA
Date: 2017
Publisher: American Chemical Society (ACS)
Date: 16-03-2021
Publisher: Springer Science and Business Media LLC
Date: 25-02-2021
Publisher: IEEE
Date: 08-2011
Publisher: IEEE
Date: 08-2011
Publisher: IEEE
Date: 08-2011
Publisher: Optica Publishing Group
Date: 2008
DOI: 10.1364/OE.16.000993
Abstract: Light emerging from a spiral phase plate with a non-integer phase step has a complicated vortex structure and is unstable on propagation. We generate light carrying fractional orbital angular momentum (OAM) not with a phase step but by a synthesis of Laguerre-Gaussian modes. By limiting the number of different Gouy phases in the superposition we produce a light beam which is well characterised in terms of its propagation. We believe that their structural stability makes these beams ideal for quantum information processes utilising fractional OAM states.
Publisher: Shanghai Institute of Optics and Fine Mechanics
Date: 2017
Publisher: Informa UK Limited
Date: 20-10-2008
Publisher: The Optical Society
Date: 03-01-2019
DOI: 10.1364/OE.27.000121
Publisher: IOP Publishing
Date: 24-06-2013
Publisher: Research Square Platform LLC
Date: 31-05-2022
DOI: 10.21203/RS.3.RS-1678298/V1
Abstract: A major roadblock to the development of photonic sensors is the scattering associated with many biological systems. We show the conservation of photonic states through optically self-arranged biological waveguides, for the first time, which can be implemented to transmit light through scattering media. The conservation of optical properties of light through biological waveguides allows for the transmission of high bandwidth information with low loss through scattering media. Here, we experimentally demonstrate the conservation of polarization state and orbital angular momentum of light through a self-arranged biological waveguide, several centimeters long, in a sheep red blood cell suspension. We utilize nonlinear optical effects to self-trap cells, which form waveguides at 532 nm and 780 nm wavelengths. Moreover, we use the formed waveguide channels to couple and guide probe beams without altering the information. The formed biological waveguides are in a sub-diffusive scattering regime, so the photons’ information degrades insignificantly over several centimeters of propagation through the scattering media. Our results show the potential of biological waveguides as a methodology for the development of novel photonic biosensors, biomedical devices that require optical wireless communication, and the development of new approaches to noninvasive biomedical imaging.
Publisher: OSA
Date: 2015
Publisher: Optica Publishing Group
Date: 05-09-2017
DOI: 10.1364/BOE.8.004310
Publisher: Optica Publishing Group
Date: 22-09-2008
DOI: 10.1364/OE.16.015897
Abstract: We present a system which uses a single spatial light modulator to control the spin angular momentum of multiple optical traps. These traps may be independently controlled both in terms of spatial location and in terms of their spin angular momentum content. The system relies on a spatial light modulator used in a "split-screen" configuration to generate beams of orthogonal polarisation states which are subsequently combined at a polarising beam splitter. Defining the phase difference between the beams with the spatial light modulator enables control of the polarisation state of the light. We demonstrate the functionality of the system by controlling the rotation and orientation of birefringent vaterite crystals within holographic optical tweezers.
Publisher: Springer Science and Business Media LLC
Date: 13-03-2019
DOI: 10.1038/S41377-019-0142-1
Abstract: Osmotic conditions play an important role in the cell properties of human red blood cells (RBCs), which are crucial for the pathological analysis of some blood diseases such as malaria. Over the past decades, numerous efforts have mainly focused on the study of the RBC biomechanical properties that arise from the unique deformability of erythrocytes. Here, we demonstrate nonlinear optical effects from human RBCs suspended in different osmotic solutions. Specifically, we observe self-trapping and scattering-resistant nonlinear propagation of a laser beam through RBC suspensions under all three osmotic conditions, where the strength of the optical nonlinearity increases with osmotic pressure on the cells. This tunable nonlinearity is attributed to optical forces, particularly the forward-scattering and gradient forces. Interestingly, in aged blood s les (with lysed cells), a notably different nonlinear behavior is observed due to the presence of free hemoglobin. We use a theoretical model with an optical force-mediated nonlocal nonlinearity to explain the experimental observations. Our work on light self-guiding through scattering bio-soft-matter may introduce new photonic tools for noninvasive biomedical imaging and medical diagnosis.
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Daryl Preece.