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multiphoton imaging

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https://www.readbyqxmd.com/read/28727765/defining-the-target-and-the-effect-of-imatinib-on-the-filarial-c-abl-homologue
#1
Elise M O'Connell, Olena Kamenyeva, Sara Lustigman, Aaron Bell, Thomas B Nutman
BACKGROUND: Previously we demonstrated the micro- and macrofilaricidal properties of imatinib in vitro. Here we use electron and multiphoton microscopy to define the target of imatinib in the adult and microfilarial stages of Brugia malayi, and assess the effects of pharmacologically relevant levels of imatinib on the adult parasites. METHODS: After fixation of adult B. malayi males and females, sections were stained with polyclonal rabbit anti-c-Abl antibody (or isotype control) and imaged with multiphoton fluorescent microscopy...
July 20, 2017: PLoS Neglected Tropical Diseases
https://www.readbyqxmd.com/read/28725020/neuronal-imaging-with-ultrahigh-dynamic-range-multiphoton-microscopy
#2
Ruohui Yang, Timothy D Weber, Ellen D Witkowski, Ian G Davison, Jerome Mertz
Multiphoton microscopes are hampered by limited dynamic range, preventing weak sample features from being detected in the presence of strong features, or preventing the capture of unpredictable bursts in sample strength. We present a digital electronic add-on technique that vastly improves the dynamic range of a multiphoton microscope while limiting potential photodamage. The add-on provides real-time negative feedback to regulate the laser power delivered to the sample, and a log representation of the sample strength to accommodate ultrahigh dynamic range without loss of information...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28717582/in-vivo-multiphoton-imaging-of-a-diverse-array-of-fluorophores-to-investigate-deep-neurovascular-structure
#3
David R Miller, Ahmed M Hassan, Jeremy W Jarrett, Flor A Medina, Evan P Perillo, Kristen Hagan, S M Shams Kazmi, Taylor A Clark, Colin T Sullender, Theresa A Jones, Boris V Zemelman, Andrew K Dunn
We perform high-resolution, non-invasive, in vivo deep-tissue imaging of the mouse neocortex using multiphoton microscopy with a high repetition rate optical parametric amplifier laser source tunable between λ=1,100 and 1,400 nm. By combining the high repetition rate (511 kHz) and high pulse energy (400 nJ) of our amplifier laser system, we demonstrate imaging of vasculature labeled with Texas Red and Indocyanine Green, and neurons expressing tdTomato and yellow fluorescent protein. We measure the blood flow speed of a single capillary at a depth of 1...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28717572/multiphoton-microscopy-for-label-free-identification-of-intramural-metastasis-in-human-esophageal-squamous-cell-carcinoma
#4
Jian Xu, Deyong Kang, Yaping Zeng, Shuangmu Zhuo, Xiaoqin Zhu, Liwei Jiang, Jianxin Chen, Jiangbo Lin
For complete removal of cancerous tissue in esophageal squamous cell carcinoma (ESCC), intramural metastasis (IM) should be identified preoperatively or intraoperatively. Here, multiphoton microscopy (MPM) was introduced for label-free identification of IM in the esophageal wall, by a combination of two-photon excited fluorescence (TPEF), second harmonic generation (SHG) imaging, and spectral analysis. Three-dimensional (3D) imaging of the IM region was also performed. Quantitative parameters, including 3D fiber orientation, were measured by 3D-weighted orientation vector summation...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28717563/multiphoton-in-vivo-imaging-with-a-femtosecond-semiconductor-disk-laser
#5
Fabian F Voigt, Florian Emaury, Philipp Bethge, Dominik Waldburger, Sandro M Link, Stefano Carta, Alexander van der Bourg, Fritjof Helmchen, Ursula Keller
We use an ultrafast diode-pumped semiconductor disk laser (SDL) to demonstrate several applications in multiphoton microscopy. The ultrafast SDL is based on an optically pumped Vertical External Cavity Surface Emitting Laser (VECSEL) passively mode-locked with a semiconductor saturable absorber mirror (SESAM) and generates 170-fs pulses at a center wavelength of 1027 nm with a repetition rate of 1.63 GHz. We demonstrate the suitability of this laser for structural and functional multiphoton in vivo imaging in both Drosophila larvae and mice for a variety of fluorophores (including mKate2, tdTomato, Texas Red, OGB-1, and R-CaMP1...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28716964/a-glun2b-selective-nmdar-antagonist-reverses-synapse-loss-and-cognitive-impairment-produced-by-the-hiv-1-protein-tat
#6
Jonathan D Raybuck, Nicholas J Hargus, Stanley A Thayer
HIV-associated neurocognitive disorder (HAND) affects approximately half of HIV-infected patients. Loss of synaptic connections is a hallmark of many neurocognitive disorders, including HAND. The HIV-1 protein transactivator of transcription (Tat) disrupts synaptic connections both in vitro and in vivo and has been linked to impaired neurocognitive function in humans. In vitro studies have shown that ifenprodil, an antagonist selective for GluN2B-containing NMDARs, reverses synapse loss when applied after Tat...
July 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28688417/slice-imaging-of-the-uv-photodissociation-of-ch2brcl-from-the-maximum-of-the-first-absorption-band
#7
D V Chicharro, S Marggi Poullain, J González-Vázquez, L Bañares
The photodissociation dynamics of bromochloromethane (CH2BrCl) have been investigated at the maximum of the first absorption band, at the excitation wavelengths 203 and 210 nm, using the slice imaging technique in combination with a probe detection of bromine-atom fragments, Br((2)P3/2) and Br*((2)P1/2), via (2 + 1) resonance enhanced multiphoton ionization. Translational energy distributions and angular distributions reported for both Br((2)P3/2) and Br*((2)P1/2) fragments show two contributions for the Br((2)P3/2) channel and a single contribution for the Br*((2)P1/2) channel...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28688411/ion-and-velocity-map-imaging-for-surface-dynamics-and-kinetics
#8
Dan J Harding, Jannis Neugebohren, Hinrich Hahn, D J Auerbach, T N Kitsopoulos, Alec M Wodtke
We describe a new instrument that uses ion imaging to study molecular beam-surface scattering and surface desorption kinetics, allowing independent determination of both residence times on the surface and scattering velocities of desorbing molecules. This instrument thus provides the capability to derive true kinetic traces, i.e., product flux versus residence time, and allows dramatically accelerated data acquisition compared to previous molecular beam kinetics methods. The experiment exploits non-resonant multiphoton ionization in the near-IR using a powerful 150-fs laser pulse, making detection more general than previous experiments using resonance enhanced multiphoton ionization...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28688406/imaging-multiphoton-ionization-and-dissociation-of-rotationally-warm-co-via-the-b-%C3%AE-1-and-e%C3%AE-1-electronic-states
#9
Z-F Sun, R J A Scheidsbach, A G Suits, D H Parker
Pathways for formation of C(+) and O(+) ions when applying (2 + 1) resonance enhanced multiphoton ionization (REMPI) of CO via the B(1)Σ(+) and E(1)Π electronic states are characterized with the velocity map imaging technique. By employing an unskimmed pulsed valve, it was possible to obtain sharp images for a wide range of initial CO J-states. Most of the atomic ion production pathways could be assigned as one- or two-photon dissociation of a series of vibrational levels of the CO(+) X(2)Σ(+) and A(2)Π states...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28688402/temperature-dependence-of-the-photodissociation-of-co2-from-high-vibrational-levels-205-230-nm-imaging-studies-of-co-x-1-%C3%AE-and-o-3-p-1-d-products
#10
S Sutradhar, B R Samanta, A K Samanta, H Reisler
The 205-230 nm photodissociation of vibrationally excited CO2 at temperatures up to 1800 K was studied using Resonance Enhanced Multiphoton Ionization (REMPI) and time-sliced Velocity Map Imaging (VMI). CO2 molecules seeded in He were heated in an SiC tube attached to a pulsed valve and supersonically expanded to create a molecular beam of rotationally cooled but vibrationally hot CO2. Photodissociation was observed from vibrationally excited CO2 with internal energies up to about 20 000 cm(-1), and CO(X(1)Σ(+)), O((3)P), and O((1)D) products were detected by REMPI...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28688397/femtosecond-dynamics-of-the-2-methylallyl-radical-a-computational-and-experimental-study
#11
Anja Röder, Kevin Issler, Lionel Poisson, Alexander Humeniuk, Matthias Wohlgemuth, Michel Comte, Fabien Lepetit, Ingo Fischer, Roland Mitric, Jens Petersen
We investigate the photodynamics of the 2-methylallyl radical by femtosecond time-resolved photoelectron imaging. The experiments are accompanied by field-induced surface hopping dynamics calculations and the simulation of time-resolved photoelectron intensities and anisotropies, giving insight into the photochemistry and nonradiative relaxation of the radical. 2-methylallyl is excited at 236 nm, 238 nm, and 240.6 nm into a 3p Rydberg state, and the subsequent dynamics is probed by multiphoton ionization using photons of 800 nm...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28688386/reaction-dynamics-of-al-co2-%C3%A2-alo-co-studied-by-a-crossed-beam-velocity-map-imaging-technique
#12
Kenji Honma, Daiki Hirata
The oxidation reaction of a gas-phase aluminum atom by a carbon dioxide molecule was studied by employing a crossed-beam technique at two collision energies: 27.9 and 52.8 kJ/mol. A (1 + 1) resonance-enhanced multiphoton ionization via the D(2)Σ(+)-X(2)Σ(+) transition of AlO was applied to ionize the product. For several rotational levels of AlO in the vibrational ground state, time-sliced ion images were measured for the first time, and the angular-kinetic energy distributions were determined. All angular distributions showed forward and backward peaks; the forward peaks were more pronounced than the backward ones at the two collision energies...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28688385/circular-dichroism-in-photoelectron-images-from-aligned-nitric-oxide-molecules
#13
Ananya Sen, S T Pratt, K L Reid
We have used velocity map photoelectron imaging to study circular dichroism of the photoelectron angular distributions (PADs) of nitric oxide following two-color resonance-enhanced two-photon ionization via selected rotational levels of the A (2)Σ(+), v(')=0 state. By using a circularly polarized pump beam and a counter-propagating, circularly polarized probe beam, cylindrical symmetry is preserved in the ionization process, and the images can be reconstructed using standard algorithms. The velocity map imaging set up enables individual ion rotational states to be resolved with excellent collection efficiency, rendering the measurements considerably simpler to perform than previous measurements conducted with a conventional photoelectron spectrometer...
July 7, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28677822/spectroscopic-characterization-of-oral-epithelial-dysplasia-and-squamous-cell-carcinoma-using-multiphoton-autofluorescence-micro-spectroscopy
#14
Rahul Pal, Kert Edward, Liang Ma, Suimin Qiu, Gracie Vargas
OBJECTIVE: Multiphoton autofluorescence microscopy (MPAM) has shown potential in identifying features that are directly related to tissue microstructural and biochemical changes throughout epithelial neoplasia. In this study, we evaluate the autofluorescence spectral characteristics of neoplastic epithelium in dysplasia and oral squamous cell carcinoma (OSCC) using multiphoton autofluorescence spectroscopy (MPAS) in an in vivo hamster model of oral neoplasia in order to identify unique signatures that could be used to delineate normal oral mucosa from neoplasia...
July 5, 2017: Lasers in Surgery and Medicine
https://www.readbyqxmd.com/read/28676880/innovations-and-developments-in-dermatologic-non-invasive-optical-imaging-and-potential-clinical-applications
#15
Eric Tkaczyk
Most dermatologists are aware of the benefits of dermoscopy, and a few are familiar with laser-scanning confocal microscopy. Beyond confocal, there are fully 11 different categories of optical techniques that have been applied to clinical dermatology. This article first provides a comprehensive tabular overview of all these optical diagnostic technologies and then details 4 of the lesser known innovations that are already available or still in development (laser Doppler and speckle imaging, Raman spectroscopy, multiphoton microscopy, photoacoustic tomography), with some potential applications in clinical dermatology (blood flow monitoring, skin cancer diagnosis, composition measurements in atopic dermatitis, skin rejuvenation measurement, and noninvasive sentinel lymph node assessment in melanoma)...
July 5, 2017: Acta Dermato-venereologica
https://www.readbyqxmd.com/read/28665439/multiphoton-autofluorescence-lifetime-imaging-of-induced-pluripotent-stem-cells
#16
Aisada Uchugonova
No abstract text is available yet for this article.
June 1, 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28664407/combined-use-of-electron-microscopy-and-intravital-imaging-captures-morphological-and-functional-features-of-podocyte-detachment
#17
REVIEW
James L Burford, Georgina Gyarmati, Isao Shirato, Wilhelm Kriz, Kevin V Lemley, János Peti-Peterdi
The development of podocyte injury and albuminuria in various glomerular pathologies is still incompletely understood due to technical limitations in studying the glomerular filtration barrier (GFB) in real-time. We aimed to directly visualize the early morphological and functional changes of the GFB during the development of focal segmental glomerulosclerosis (FSGS) using a combination of transmission electron microscopy (TEM) and in vivo multiphoton microscopy (MPM) in the rat puromycin aminonucleoside (PAN) model...
June 29, 2017: Pflügers Archiv: European Journal of Physiology
https://www.readbyqxmd.com/read/28663908/transient-absorption-imaging-of-hemes-with-2-color-independently-tunable-visible-wavelength-ultrafast-source
#18
Scott R Domingue, Randy A Bartels, Adam J Chicco, Jesse W Wilson
Pump probe microscopy is a time-resolved multiphoton imaging technique capable of generating contrast between non-fluorescent pigments based on differences in excited-state lifetimes. Here we describe a fiber-based ultrafast system designed for imaging heme proteins with an independently-tunable pulse pair in the visible-wavelength regime. Starting with a 1060 nm fiber amplifier (1.3 W at 63 MHz, 140 fs pulses), visible pulses were produced in the vicinity of 488 nm and 532 nm by doubling the output of a short photonic crystal fiber with a pair of periodically-poled lithium niobate crystals, providing 5-20 mW power in each beam...
June 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28659757/the-role-of-kv7-m-potassium-channels-in-controlling-ectopic-firing-in-nociceptors
#19
Omer Barkai, Robert H Goldstein, Yaki Caspi, Ben Katz, Shaya Lev, Alexander M Binshtok
Peripheral nociceptive neurons encode and convey injury-inducing stimuli toward the central nervous system. In normal conditions, tight control of nociceptive resting potential prevents their spontaneous activation. However, in many pathological conditions the control of membrane potential is disrupted, leading to ectopic, stimulus-unrelated firing of nociceptive neurons, which is correlated to spontaneous pain. We have investigated the role of KV7/M channels in stabilizing membrane potential and impeding spontaneous firing of nociceptive neurons...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28644009/multi-harmonic-imaging-in-the-second-near-infrared-window-of-nanoparticle-labeled-stem-cells-as-a-monitoring-tool-in-tissue-depth
#20
Laurence Dubreil, Isabelle Leroux, Mireille Ledevin, Cindy Schleder, Lydie Lagalice, Claire Lovo, Romain Fleurisson, Solene Passemard, Vasyl Kilin, Sandrine Gerber-Lemaire, Marie-Anne Colle, Luigi Bonacina, Karl Rouger
In order to assess the therapeutic potential of cell-based strategies, it is of paramount importance to elaborate and validate tools for monitoring the behavior of injected cells in terms of tissue dissemination and engraftment properties. Here, we apply bismuth ferrite harmonic nanoparticles (BFO HNPs) to in vitro expanded human skeletal muscle-derived stem cells (hMuStem cells), an attractive therapeutic avenue for patients suffering from Duchenne muscular dystrophy (DMD). We demonstrate the possibility of stem cell labeling with HNPs...
June 27, 2017: ACS Nano
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