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multiphoton imaging

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https://www.readbyqxmd.com/read/28211922/applying-phasor-approach-analysis-of-multiphoton-flim-measurements-to-probe-the-metabolic-activity-of-three-dimensional-in-vitro-cell-culture-models
#1
Pirmin H Lakner, Michael G Monaghan, Yvonne Möller, Monilola A Olayioye, Katja Schenke-Layland
Fluorescence lifetime imaging microscopy (FLIM) can measure and discriminate endogenous fluorophores present in biological samples. This study seeks to identify FLIM as a suitable method to non-invasively detect a shift in cellular metabolic activity towards glycolysis or oxidative phosphorylation in 3D Caco-2 models of colorectal carcinoma. These models were treated with potassium cyanide or hydrogen peroxide as controls, and epidermal growth factor (EGF) as a physiologically-relevant influencer of cell metabolic behaviour...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28211728/electron-vortices-in-femtosecond-multiphoton-ionization
#2
D Pengel, S Kerbstadt, D Johannmeyer, L Englert, T Bayer, M Wollenhaupt
Multiphoton ionization of potassium atoms with a sequence of two counter-rotating circularly polarized femtosecond laser pulses produces vortex-shaped photoelectron momentum distributions in the polarization plane describing Archimedean spirals. The pulse sequences are produced by polarization shaping and the three-dimensional photoelectron distributions are tomographically reconstructed from velocity map imaging measurements. We show that perturbative ionization leads to electron vortices with c_{6} rotational symmetry...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28198734/new-frontiers-in-intravital-microscopy-of-the-kidney
#3
Andrew M Hall, Claus D Schuh, Dominik Haenni
PURPOSE OF REVIEW: Intravital imaging with multiphoton microscopy enables the detailed study of dynamic cellular processes within functioning organs in living animals, in ways that would not otherwise be possible. It therefore represents a powerful tool in translational kidney research. In this article, we will discuss several new technical developments that have significantly increased the capabilities of kidney imaging. RECENT FINDINGS: Important contemporary advances in biomedical imaging technology include longer wavelength excitation lasers, far-red emitting fluorescent reporters, highly sensitive detectors, fluorescence lifetime measurements, adaptive optics, microendoscopes, high-throughput automated analysis algorithms and tissue clearing techniques...
February 13, 2017: Current Opinion in Nephrology and Hypertension
https://www.readbyqxmd.com/read/28192297/controlling-and-tracking-of-colloidal-nanostructures-through-two-photon-fluorescence
#4
Dipankar Mondal, Debabrata Goswami
Multiphoton absorbing dye-coated trapped spherical bead at the focal plane of femtosecond optical tweezers shows nonlinear optical (NLO) phenomena. One such NLO process of two-photon fluorescence (TPF) has been used for the background-free imaging of a femtosecond laser-trapping event. Due to the high peak powers of femtosecond laser pulses with low average powers, it is possible to not only trap single nanospheres, but encourage optically directed self-assembly. The TPF signatures of trapped particles show evidence of such a directed self-assembly process which, in turn, can provide information about the structural dynamics during the process of cluster formation...
October 7, 2016: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28164461/flexible-polygon-mirror-based-laser-scanning-microscope-platform-for-multiphoton-in-vivo-imaging
#5
Y X Li, V Gautam, A Brüstle, I A Cockburn, V R Daria, C Gillespie, K Gaus, C Alt, W M Lee
Commercial microscopy systems make use of tandem scanning i.e. either slow or fast scanning. We constructed, for the first time, an advanced control system capable of delivering a dynamic line scanning speed ranging from 2.7 kHz to 27 kHz and achieve variable frame rates from 5 Hz to 50 Hz (512 × 512). The dynamic scanning ability is digitally controlled by a new customized open-source software named PScan1.0. This permits manipulation of scanning rates either to gain higher fluorescence signal at slow frame rate without increasing laser power or increase frame rates to capture high speed events...
February 6, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28156058/aging-and-caloric-restriction-impact-adipose-tissue-adiponectin-and-circulating-lipids
#6
Karl N Miller, Maggie S Burhans, Josef P Clark, Porsha R Howell, Michael A Polewski, Tyler M DeMuth, Kevin W Eliceiri, Mary J Lindstrom, James M Ntambi, Rozalyn M Anderson
Adipose tissue expansion has been associated with system-wide metabolic dysfunction and increased vulnerability to diabetes, cancer, and cardiovascular disease. A reduction in adiposity is a hallmark of caloric restriction (CR), an intervention that extends longevity and delays the onset of these same age-related conditions. Despite these parallels, the role of adipose tissue in coordinating the metabolism of aging is poorly defined. Here, we show that adipose tissue metabolism and secretory profiles change with age and are responsive to CR...
February 3, 2017: Aging Cell
https://www.readbyqxmd.com/read/28151005/allograft-heart-valves-current-aspects-and-future-applications
#7
Milan Lisy, Guenay Kalender, Katja Schenke-Layland, Kelvin G M Brockbank, Anna Biermann, Ulrich Alfred Stock
Human heart valve allografts continue to represent almost perfect substitutes for heart valves. They have optimal hemodynamic characteristics and are highly resistant to infections. The first clinical use of allograft heart valves was as homovitals being transplanted after antibiotic incubation without any preservation. Since 1968, relatively standardized frozen cryopreservation (SFC) has been employed, including storage in vapor-phase liquid nitrogen. Disadvantages, particularly in pediatric patients, are limited availability due to organ scarcity, inability to grow, degeneration, immune response, and long-term failure...
February 2, 2017: Biopreservation and Biobanking
https://www.readbyqxmd.com/read/28147527/photodissociation-of-acetone-from-266-to-312-nm-dynamics-of-ch3-ch3co-channels-on-the-s0-and-t1-states
#8
Kin Long Kelvin Lee, Klaas Nauta, Scott H Kable
The photodissociation dynamics of acetone (CH3)2CO, cooled in a molecular beam, have been explored over the wavelength range 266-312 nm. Nascent CH3 fragments were detected by resonance-enhanced multiphoton ionization, followed by mass-selected ion imaging. For photolysis at λ = 306 nm, the image shows a sharp ring, which, when converted to a translational energy distribution, reveals a narrow Gaussian peak with a maximum at 90% of the available energy. As the photolysis energy is increased, the distribution slowly broadens and shifts to higher recoil translational energy...
January 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28146237/measuring-deformation-in-the-mouse-optic-nerve-head-and-peripapillary-sclera
#9
Cathy Nguyen, Dan Midgett, Elizabeth C Kimball, Matthew R Steinhart, Thao D Nguyen, Mary E Pease, Ericka N Oglesby, Joan L Jefferys, Harry A Quigley
Purpose: To develop an ex vivo explant system using multiphoton microscopy and digital volume correlation to measure the full-field deformation response to intraocular pressure (IOP) change in the peripapillary sclera (PPS) and in the optic nerve head (ONH) astrocytic structure. Methods: Green fluorescent protein (GFP)-glutamate transporter-GLT1 (GLT1/GFP) mouse eyes were explanted and imaged with a laser-scanning microscope under controlled inflation. Images were analyzed for regional strains and changes in astrocytic lamina and PPS shape...
February 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28133923/a-comparative-study-of-ex-vivo-skin-optical-clearing-using-two-photon-microscopy
#10
Anton Sdobnov, Maxim E Darvin, Juergen Lademann, Valery Tuchin
Multiphoton tomography (MPT) is a prospective tool for imaging the skin structure. Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (Omnipaque(TM) ) at different concentrations, which exhibit different osmotic properties. The results show that a topical application of glycerol or Omnipaque(TM) solutions onto the skin for 60 min significantly improved the depth and contrast of the MPT signals...
January 30, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28127600/collision-energy-dependence-of-state-to-state-differential-cross-sections-for-rotationally-inelastic-scattering-of-h2o-by-he
#11
Gautam Sarma, Ashim Kumar Saha, Chandan Kumar Bishwakarma, Roy Scheidsbach, Chung-Hsin Yang, David Parker, Laurent Wiesenfeld, Udo Buck, Lazaros Mavridis, Sarantos Marinakis
The inelastic scattering of H2O by He as a function of collision energy in the range 381 cm(-1) to 763 cm(-1) at an energy interval of approximately 100 cm(-1) has been investigated in a crossed beam experiment using velocity map imaging. Change in collision energy was achieved by varying the collision angle between the H2O and He beam. We measured the state-to-state differential cross section (DCS) of scattered H2O products for the final rotational states JKaKc = 110, 111, 221 and 414. Rotational excitation of H2O is probed by (2 + 1) resonance enhanced multiphoton ionization (REMPI) spectroscopy...
January 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28122218/molecular-scale-biophysical-modulation-of-an-endothelial-membrane-by-oxidized-phospholipids
#12
Manuela A A Ayee, Elizabeth LeMaster, Tzu Pin Shentu, Dev K Singh, Nicolas Barbera, Dheeraj Soni, Chinnaswamy Tiruppathi, Papasani V Subbaiah, Evgeny Berdyshev, Irina Bronova, Michael Cho, Belinda S Akpa, Irena Levitan
The influence of two bioactive oxidized phospholipids on model bilayer properties, membrane packing, and endothelial cell biomechanics was investigated computationally and experimentally. The truncated tail phospholipids, 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) and 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphocholine (PGPC), are two major oxidation products of the unsaturated phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphocholine. A combination of coarse-grained molecular dynamics simulations, Laurdan multiphoton imaging, and atomic force microscopy microindentation experiments was used to determine the impact of POVPC and PGPC on the structure of a multicomponent phospholipid bilayer and to assess the consequences of their incorporation on membrane packing and endothelial cell stiffness...
January 24, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28106426/unified-time-and-frequency-picture-of-ultrafast-atomic-excitation-in-strong-laser-fields
#13
H Zimmermann, S Patchkovskii, M Ivanov, U Eichmann
Excitation and ionization in strong laser fields lies at the heart of such diverse research directions as high-harmonic generation and spectroscopy, laser-induced diffraction imaging, emission of femtosecond electron bunches from nanotips, self-guiding, filamentation and mirrorless lasing during propagation of light in atmospheres. While extensive quantum mechanical and semiclassical calculations on strong-field ionization are well backed by sophisticated experiments, the existing scattered theoretical work aiming at a full quantitative understanding of strong-field excitation lacks experimental confirmation...
January 6, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28101420/compact-diode-laser-source-for-multiphoton-biological-imaging
#14
Robert D Niederriter, Baris N Ozbay, Gregory L Futia, Emily A Gibson, Juliet T Gopinath
We demonstrate a compact, pulsed diode laser source suitable for multiphoton microscopy of biological samples. The center wavelength is 976 nm, near the peak of the two-photon cross section of common fluorescent markers such as genetically encoded green and yellow fluorescent proteins. The laser repetition rate is electrically tunable between 66.67 kHz and 10 MHz, with 2.3 ps pulse duration and peak powers >1 kW. The laser components are fiber-coupled and scalable to a compact package. We demonstrate >600 μm depth penetration in brain tissue, limited by laser power...
January 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28063434/integral-steric-asymmetry-in-the-inelastic-scattering-of-no-x-2-%C3%AE
#15
M Brouard, S D S Gordon, A Hackett Boyle, C G Heid, B Nichols, V Walpole, F J Aoiz, S Stolte
The integral steric asymmetry for the inelastic scattering of NO(X) by a variety of collision partners was recorded using a crossed molecular beam apparatus. The initial state of the NO(X, v = 0, j = 1/2, Ω=1/2, ϵ=-1,f) molecule was selected using a hexapole electric field, before the NO bond axis was oriented in a static electric field, allowing probing of the scattering of the collision partner at either the N- or O-end of the molecule. Scattered NO molecules were state selectively probed using (1 + 1') resonantly enhanced multiphoton ionisation, coupled with velocity-map ion imaging...
January 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28063036/visualization-of-the-t-cell-response-in-contact-hypersensitivity
#16
Gyohei Egawa, Kenji Kabashima
Contact hypersensitivity (CHS) is the most basic murine model for type IV hypersensitivity. This dermatitis model is mediated by hapten-sensitized, skin-infiltrating T cells. Recent intravital imaging studies have demonstrated the dynamic migratory property of skin-infiltrating T cells and the orchestrated interaction of T cells with dermal dendritic cells. Multiphoton microscopy enables the direct, three-dimensional, and minimally invasive imaging of in vivo skin samples with high spatiotemporal resolution...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28060277/inducing-ischemia-reperfusion-injury-in-the-mouse-ear-skin-for-intravital-multiphoton-imaging-of-immune-responses
#17
Chi Ching Goh, Jackson LiangYao Li, David Becker, Wolfgang Weninger, Veronique Angeli, Lai Guan Ng
Ischemia-reperfusion injury (IRI) occurs when there is transient hypoxia due to the obstruction of blood flow (ischemia) followed by a subsequent re-oxygenation of the tissues (reperfusion). In the skin, ischemia-reperfusion (IR) is the main contributing factor to the pathophysiology of pressure ulcers. While the cascade of events leading up to the inflammatory response has been well studied, the spatial and temporal responses of the different subsets of immune cells to an IR injury are not well understood...
December 22, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28059135/labeling-and-in-vivo-visualization-of-transplanted-adipose-tissue-derived-stem-cells-with-safe-cadmium-free-aqueous-zns-coating-of-zns-agins2-nanoparticles
#18
Yusuke Ogihara, Hiroshi Yukawa, Tatsuya Kameyama, Hiroyasu Nishi, Daisuke Onoshima, Tetsuya Ishikawa, Tsukasa Torimoto, Yoshinobu Baba
The facile synthesis of ZnS-AgInS2 (ZAIS) as cadmium-free QDs and their application, mainly in solar cells, has been reported by our groups. In the present study, we investigated the safety and the usefulness for labeling and in vivo imaging of a newly synthesized aqueous ZnS-coated ZAIS (ZnS-ZAIS) carboxylated nanoparticles (ZZC) to stem cells. ZZC shows the strong fluorescence in aqueous solutions such as PBS and cell culture medium, and a complex of ZZC and octa-arginine (R8) peptides (R8-ZZC) can achieve the highly efficient labeling of adipose tissue-derived stem cells (ASCs)...
January 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28043893/a-novel-microstructural-interpretation-for-the-biomechanics-of-mouse-skin-derived-from-multiscale-characterization
#19
Barbara Lynch, Stéphane Bancelin, Christelle Bonod-Bidaud, Jean-Baptiste Gueusquin, Florence Ruggiero, Marie-Claire Schanne-Klein, Jean-Marc Allain
: Skin is a complex, multi-layered organ, with important functions in the protection of the body. The dermis provides structural support to the epidermal barrier, and thus has attracted a large number of mechanical studies. As the dermis is made of a mixture of stiff fibres embedded in a soft non-fibrillar matrix, it is classically considered that its mechanical response is based on an initial alignment of the fibres, followed by the stretching of the aligned fibres. Using a recently developed set-up combining multiphoton microscopy with mechanical assay, we imaged the fibres network evolution during dermis stretching...
December 30, 2016: Acta Biomaterialia
https://www.readbyqxmd.com/read/28036196/superresolving-imaging-of-arbitrary-one-dimensional-arrays-of-thermal-light-sources-using-multiphoton-interference
#20
Anton Classen, Felix Waldmann, Sebastian Giebel, Raimund Schneider, Daniel Bhatti, Thomas Mehringer, Joachim von Zanthier
We propose to use multiphoton interferences of photons emitted from statistically independent thermal light sources in combination with linear optical detection techniques to reconstruct, i.e., image, arbitrary source geometries in one dimension with subclassical resolution. The scheme is an extension of earlier work [S. Oppel et al., Phys. Rev. Lett. 109, 233603 (2012)], where N regularly spaced sources in one dimension were imaged by use of the Nth-order intensity correlation function. Here, we generalize the scheme to reconstruct any number of independent thermal light sources at arbitrary separations in one dimension, exploiting intensity correlation functions of order m≥3...
December 16, 2016: Physical Review Letters
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