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https://www.readbyqxmd.com/read/28324601/two-photon-intravital-microscopy-animal-preparation-protocol-to-study-cellular-dynamics-in-pathogenesis
#1
Erinke van Grinsven, Chloé Prunier, Nienke Vrisekoop, Laila Ritsma
Two-photon intravital microscopy (2P-IVM) is an advanced imaging platform that allows the visualization of dynamic processes at subcellular resolution in vivo. Dynamic processes like cell migration, cell proliferation, cell-cell interactions, and cell signaling have an interactive character and occur in complex environments. Hence, it is of pivotal importance to study these processes in living animals, using for example 2P-IVM. 2P-IVM can be performed on a variety of tissues, from the skin of the animal to internal organs, and a variety of methods can be utilized to perform 2P-IVM on these tissues...
2017: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28319608/cerebellar-granule-cells-acquire-a-widespread-predictive-feedback-signal-during-motor-learning
#2
Andrea Giovannucci, Aleksandra Badura, Ben Deverett, Farzaneh Najafi, Talmo D Pereira, Zhenyu Gao, Ilker Ozden, Alexander D Kloth, Eftychios Pnevmatikakis, Liam Paninski, Chris I De Zeeuw, Javier F Medina, Samuel S-H Wang
Cerebellar granule cells, which constitute half the brain's neurons, supply Purkinje cells with contextual information necessary for motor learning, but how they encode this information is unknown. Here we show, using two-photon microscopy to track neural activity over multiple days of cerebellum-dependent eyeblink conditioning in mice, that granule cell populations acquire a dense representation of the anticipatory eyelid movement. Initially, granule cells responded to neutral visual and somatosensory stimuli as well as periorbital airpuffs used for training...
March 20, 2017: Nature Neuroscience
https://www.readbyqxmd.com/read/28319259/label-free-identification-of-the-microstructure-of-rat-spinal-cords-based-on-nonlinear-optical-microscopy
#3
C X Liao, Z Y Wang, Y Zhou, L Q Zhou, X Q Zhu, W G Liu, J X Chen
The spinal cord is a vital link between the brain and the body and mainly comprises neurons, glial cells and nerve fibres. In this work, nonlinear optical (NLO) microscopy based on intrinsic tissue properties was employed to label-freely analyze the cells and matrix in spinal cords at a molecular level. The high-resolution and high-contrast NLO images of unstained spinal cords demonstrate that NLO microscopy has the ability to show the microstructure of white and grey matter including ventral horn, intermediate area, dorsal horns, ventral column, lateral column and dorsal column...
March 20, 2017: Journal of Microscopy
https://www.readbyqxmd.com/read/28319111/volumetric-two-photon-imaging-of-neurons-using-stereoscopy-vtwins
#4
Alexander Song, Adam S Charles, Sue Ann Koay, Jeff L Gauthier, Stephan Y Thiberge, Jonathan W Pillow, David W Tank
Two-photon laser scanning microscopy of calcium dynamics using fluorescent indicators is a widely used imaging method for large-scale recording of neural activity in vivo. Here, we introduce volumetric two-photon imaging of neurons using stereoscopy (vTwINS), a volumetric calcium imaging method that uses an elongated, V-shaped point spread function to image a 3D brain volume. Single neurons project to spatially displaced 'image pairs' in the resulting 2D image, and the separation distance between projections is proportional to depth in the volume...
March 20, 2017: Nature Methods
https://www.readbyqxmd.com/read/28318347/teratogenic-hazard-of-bpei-coated-silver-nanoparticles-to-xenopus-laevis
#5
Anita Colombo, Melissa Saibene, Elisa Moschini, Patrizia Bonfanti, Maddalena Collini, Kaja Kasemets, Paride Mantecca
Silver nanoparticles (AgNPs) are among the most exploited antimicrobial agents and are used in many consumer products. Size and surface reactivity are critical physico-chemical properties responsible for NPs toxicity, and surface coatings, often used to functionalize or stabilize AgNPs, can influence their toxic profile and biocompatibility. In the current study the developmental toxicity of 1) negatively charged citrate-coated AgNPs (Cit-AgNPs), 2) positively charged branched polyethylenimine-coated AgNPs (BPEI-AgNPs), and 3) Ag(+) (from 0...
March 20, 2017: Nanotoxicology
https://www.readbyqxmd.com/read/28317197/structural-photophysical-and-magnetic-circular-dichroism-studies-of-three-rigidified-meso-pentafluorophenyl-substituted-hexaphyrin-analogues
#6
Jonathan L Sessler, Masatoshi Ishida, Taniyuki Furuyama, Jong Min Lim, Sangsu Lee, Zhan Zhang, Sudip K Ghosh, Vincent M Lynch, Changhee Lee, Nagao Kobayashi, Dongho Kim
Detailed electronic, structural, photophysical, and redox studies of a series of meso-(pentafluorophenyl)-substituted hexaphyrins, namely amethyrin (1), rosarin (2) and rubyrin (3) are described. In prior work, it was found that the electronic states of the antiaromatic hexapyrrolic macrocycle, [24]rosarin 2, could be modified by exposure to several Brønsted acids (e.g., HCl, HBr and HI) to produce either one- and two-electron reduced species, or both. In an effort to gain further insights into the reactivity of hexaphyrins possessing different π-conjugation pathways, the β-dodecamethyl-substituted [24]amethyrin 1 was prepared and its electronic structure was analyzed along with that of the o-phenylene-bridged [26]rubyrin 3 and rosarin 2 The [4n] and [4n+2] π-conjugated formulations of 2 and 3, respectively, were inferred from steady-state, fs-transient absorption and two photon absorption measurements...
March 20, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/28306315/hard-two-photon-contribution-to-elastic-lepton-proton-scattering-determined-by-the-olympus-experiment
#7
B S Henderson, L D Ice, D Khaneft, C O'Connor, R Russell, A Schmidt, J C Bernauer, M Kohl, N Akopov, R Alarcon, O Ates, A Avetisyan, R Beck, S Belostotski, J Bessuille, F Brinker, J R Calarco, V Carassiti, E Cisbani, G Ciullo, M Contalbrigo, R De Leo, J Diefenbach, T W Donnelly, K Dow, G Elbakian, P D Eversheim, S Frullani, Ch Funke, G Gavrilov, B Gläser, N Görrissen, D K Hasell, J Hauschildt, Ph Hoffmeister, Y Holler, E Ihloff, A Izotov, R Kaiser, G Karyan, J Kelsey, A Kiselev, P Klassen, A Krivshich, I Lehmann, P Lenisa, D Lenz, S Lumsden, Y Ma, F Maas, H Marukyan, O Miklukho, R G Milner, A Movsisyan, M Murray, Y Naryshkin, R Perez Benito, R Perrino, R P Redwine, D Rodríguez Piñeiro, G Rosner, U Schneekloth, B Seitz, M Statera, A Thiel, H Vardanyan, D Veretennikov, C Vidal, A Winnebeck, V Yeganov
The OLYMPUS Collaboration reports on a precision measurement of the positron-proton to electron-proton elastic cross section ratio, R_{2γ}, a direct measure of the contribution of hard two-photon exchange to the elastic cross section. In the OLYMPUS measurement, 2.01 GeV electron and positron beams were directed through a hydrogen gas target internal to the DORIS storage ring at DESY. A toroidal magnetic spectrometer instrumented with drift chambers and time-of-flight scintillators detected elastically scattered leptons in coincidence with recoiling protons over a scattering angle range of ≈20° to 80°...
March 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28302854/revealing-the-subfemtosecond-dynamics-of-orbital-angular-momentum-in-nanoplasmonic-vortices
#8
G Spektor, D Kilbane, A K Mahro, B Frank, S Ristok, L Gal, P Kahl, D Podbiel, S Mathias, H Giessen, F-J Meyer Zu Heringdorf, M Orenstein, M Aeschlimann
The ability of light to carry and deliver orbital angular momentum (OAM) in the form of optical vortices has attracted much interest. The physical properties of light with a helical wavefront can be confined onto two-dimensional surfaces with subwavelength dimensions in the form of plasmonic vortices, opening avenues for thus far unknown light-matter interactions. Because of their extreme rotational velocity, the ultrafast dynamics of such vortices remained unexplored. Here we show the detailed spatiotemporal evolution of nanovortices using time-resolved two-photon photoemission electron microscopy...
March 17, 2017: Science
https://www.readbyqxmd.com/read/28302649/endothelial-protective-monocyte-patrolling-in-large-arteries-intensified-by-western-diet-and-atherosclerosis
#9
Amado Quintar, Sara McArdle, Dennis Wolf, Alex Marki, Erik Ehinger, Melanie Vassallo, Jacqueline F Miller, Zbigniew Mikulski, Klaus Ley, Konrad Buscher
Rationale: Non-classical mouse monocyte (CX3CR1(high), Ly-6C(low)) patrolling along the vessels of the microcirculation is critical for endothelial homeostasis and inflammation. Due to technical challenges it is currently not established how patrolling occurs in large arteries. Objective: This study was undertaken to elucidate the molecular, migratory and functional phenotype of patrolling monocytes in the high shear and pulsatile environment of large arteries in healthy, hyperlipidemic and atherosclerotic conditions...
March 16, 2017: Circulation Research
https://www.readbyqxmd.com/read/28301770/imaging-and-optically-manipulating-neuronal-ensembles
#10
Luis Carrillo-Reid, Weijian Yang, Jae-Eun Kang Miller, Darcy S Peterka, Rafael Yuste
The neural code that relates the firing of neurons to the generation of behavior and mental states must be implemented by spatiotemporal patterns of activity across neuronal populations. These patterns engage selective groups of neurons, called neuronal ensembles, which are emergent building blocks of neural circuits. We review optical and computational methods, based on two-photon calcium imaging and two-photon optogenetics, to detect, characterize, and manipulate neuronal ensembles in three dimensions. We review data using these methods in the mammalian cortex that demonstrate the existence of neuronal ensembles in the spontaneous and evoked cortical activity in vitro and in vivo...
March 15, 2017: Annual Review of Biophysics
https://www.readbyqxmd.com/read/28301654/mapping-of-hemoglobin-in-erythrocytes-and-erythrocyte-ghosts-using-two-photon-excitation-fluorescence-microscopy
#11
Katarina Bukara, Svetlana Jovanic, Ivana T Drvenica, Ana Stancic, Vesna Ilic, Mihailo D Rabasovic, Dejan Pantelic, Branislav Jelenkovic, Branko Bugarski, Aleksandar J Krmpot
No abstract text is available yet for this article.
February 1, 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28300041/surface-micromorphology-of-cross-linked-tetrafunctional-polylactide-scaffolds-inducing-vessel-growth-and-bone-formation
#12
Daria Kuznetsova, Aleksey Ageykin, Anastasia Koroleva, Andrea Deiwick, Anastasia Shpichka, Anna Solovieva, Sergey Kostjuk, Aleksandra Meleshina, Svetlana Rodimova, Anastasia Akovanceva, Denis Butnaru, Anastasia Frolova, Elena Zagaynova, Boris Chichkov, Victor Bagratashvili, Peter Timashev
In the presented study, we have developed a synthetic strategy allowing a gradual variation of a polylactide arms' length, which later influences the micromorphology of the scaffold surface, formed by a two-photon polymerization technique. It has been demonstrated that the highest number of cells is present on the scaffolds with the roughest surface made of the polylactide with longer arms (PLA760), and osteogenic differentiation of mesenchymal stem cells is most pronounced on such scaffolds. According to the results of biological testing, the PLA760 scaffolds were implanted into a created cranial defect in a mouse for an in vivo assessment of the bone tissue formation...
March 16, 2017: Biofabrication
https://www.readbyqxmd.com/read/28297671/selective-suppression-of-local-circuits-during-movement-preparation-in-the-mouse-motor-cortex
#13
Masashi Hasegawa, Kei Majima, Takahide Itokazu, Takakuni Maki, Urban-Raphael Albrecht, Nora Castner, Mariko Izumo, Kazuhiro Sohya, Tatsuo K Sato, Yukiyasu Kamitani, Takashi R Sato
Prepared movements are more efficient than those that are not prepared for. Although changes in cortical activity have been observed prior to a forthcoming action, the circuits involved in motor preparation remain unclear. Here, we use in vivo two-photon calcium imaging to uncover changes in the motor cortex during variable waiting periods prior to a forepaw reaching task in mice. Consistent with previous reports, we observed a subset of neurons with increased activity during the waiting period; however, these neurons did not account for the degree of preparation as defined by reaction time (RT)...
March 14, 2017: Cell Reports
https://www.readbyqxmd.com/read/28297662/extracellular-glutamate-in-the-nucleus-accumbens-is-nanomolar-in-both-synaptic-and-non-synaptic-compartments
#14
Delia N Chiu, Craig E Jahr
In the CNS, glutamate is both phasically and tonically released into the extracellular space and must be removed by excitatory amino acid transporters (EAATs) to prevent excitotoxic accumulation. There remains uncertainty, however, regarding the functional steady-state concentration, with estimates ranging from tens of nanomolar to tens of micromolar. Efforts to reconcile these disparate values have led to a hypothesis that the extracellular space comprises distinct compartments in which basal glutamate concentrations are maintained independently...
March 14, 2017: Cell Reports
https://www.readbyqxmd.com/read/28295105/combined-static-and-dynamic-quenching-in-micellar-systems-closed-form-integrated-rate-laws-verified-using-a-versatile-probe
#15
Tim Kohlmann, Robert Naumann, Christoph Kerzig, Martin Goez
We demonstrate that the 3-aminoperylene radical cation is a near-ideal probe for investigating kinetic and transport processes in SDS micellar systems. Its isolated generation by two-photon ionization at a wavelength where most quenchers are transparent (532 nm) is free from side reactions; no exit from the micelles is detectable on a millisecond timescale; and its unquenched lifetime is as long as 350 ms, thus allowing the study of quenching processes over a time frame spanning at least 7 orders of magnitude...
March 15, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28295068/two-photon-shack-hartmann-wavefront-sensor
#16
Fei Xia, David Sinefeld, Bo Li, Chris Xu
We introduce a simple wavefront sensing scheme for aberration measurement of pulsed laser beams in near-infrared wavelengths (<2200  nm), where detectors are not always available or are very expensive. The method is based on two-photon absorption in a silicon detector array for longer wavelengths detection. We demonstrate the simplicity of such implementations with a commercially available Shack-Hartmann wavefront sensor and discuss the detection sensitivity of this method.
March 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28293175/two-photon-na-imaging-reports-somatically-evoked-action-potentials-in-rat-olfactory-bulb-mitral-and-granule-cell-neurites
#17
Tiffany Ona-Jodar, Niklas J Gerkau, S Sara Aghvami, Christine R Rose, Veronica Egger
Dendrodendritic synaptic interactions are a hallmark of neuronal processing in the vertebrate olfactory bulb. Many classes of olfactory bulb neurons including the principal mitral cells (MCs) and the axonless granule cells (GCs) dispose of highly efficient propagation of action potentials (AP) within their dendrites, from where they can release transmitter onto each other. So far, backpropagation in GC dendrites has been investigated indirectly via Ca(2+) imaging. Here, we used two-photon Na(+) imaging to directly report opening of voltage-gated sodium channels due to AP propagation in both cell types...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28289377/loss-of-saltation-and-presynaptic-action-potential-failure-in-demyelinated-axons
#18
Mustafa S Hamada, Marko A Popovic, Maarten H P Kole
In cortical pyramidal neurons the presynaptic terminals controlling transmitter release are located along unmyelinated axon collaterals, far from the original action potential (AP) initiation site, the axon initial segment (AIS). Once initiated, APs will need to reliably propagate over long distances and regions of geometrical inhomogeneity like branch points (BPs) to rapidly depolarize the presynaptic terminals and confer temporally precise synaptic transmission. While axon pathologies such as demyelinating diseases are well established to impede the fidelity of AP propagation along internodes, to which extent myelin loss affects propagation along BPs and axon collaterals is not well understood...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28285819/imaging-erk-and-pka-activation-in-single-dendritic-spines-during-structural-plasticity
#19
Shen Tang, Ryohei Yasuda
Extracellular signal-regulated kinase (ERK) and protein kinase A (PKA) play important roles in LTP and spine structural plasticity. While fluorescence resonance energy transfer (FRET)-based sensors for these kinases had previously been developed, they did not provide sufficient sensitivity for imaging small neuronal compartments, such as single dendritic spines in brain slices. Here we improved the sensitivity of FRET-based kinase sensors for monitoring kinase activity under two-photon fluorescence lifetime imaging microscopy (2pFLIM)...
March 6, 2017: Neuron
https://www.readbyqxmd.com/read/28282180/entanglement-by-path-identity
#20
Mario Krenn, Armin Hochrainer, Mayukh Lahiri, Anton Zeilinger
Quantum entanglement is one of the most prominent features of quantum mechanics and forms the basis of quantum information technologies. Here we present a novel method for the creation of quantum entanglement in multipartite and high-dimensional systems. The two ingredients are (i) superposition of photon pairs with different origins and (ii) aligning photons such that their paths are identical. We explain the experimentally feasible creation of various classes of multiphoton entanglement encoded in polarization as well as in high-dimensional Hilbert spaces-starting only from nonentangled photon pairs...
February 24, 2017: Physical Review Letters
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