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https://www.readbyqxmd.com/read/28106426/unified-time-and-frequency-picture-of-ultrafast-atomic-excitation-in-strong-laser-fields
#1
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/28106422/circular-dichroism-in-multiphoton-ionization-of-resonantly-excited-he-ions
#2
M Ilchen, N Douguet, T Mazza, A J Rafipoor, C Callegari, P Finetti, O Plekan, K C Prince, A Demidovich, C Grazioli, L Avaldi, P Bolognesi, M Coreno, M Di Fraia, M Devetta, Y Ovcharenko, S Düsterer, K Ueda, K Bartschat, A N Grum-Grzhimailo, A V Bozhevolnov, A K Kazansky, N M Kabachnik, M Meyer
Intense, circularly polarized extreme-ultraviolet and near-infrared (NIR) laser pulses are combined to double ionize atomic helium via the oriented intermediate He^{+}(3p) resonance state. Applying angle-resolved electron spectroscopy, we find a large photon helicity dependence of the spectrum and the angular distribution of the electrons ejected from the resonance by NIR multiphoton absorption. The measured circular dichroism is unexpectedly found to vary strongly as a function of the NIR intensity. The experimental data are well described by theoretical modeling and possible mechanisms are discussed...
January 6, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28101420/compact-diode-laser-source-for-multiphoton-biological-imaging
#3
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/28069694/myocardial-tissue-engineering-with-cells-derived-from-human-induced-pluripotent-stem-cells-and-a-native-like-high-resolution-3-dimensionally-printed-scaffold
#4
Ling Gao, Molly Kupfer, Jangwook Jung, Libang Yang, Patrick Zhang, Yong Sie, Quyen Tran, Visar Ajeti, Brian Freeman, Vladimir Fast, Paul Campagnola, Brenda Ogle, Jianyi Zhang
RATIONALE: Conventional three-dimensional (3D) printing techniques cannot produce structures of the size at which individual cells interact. OBJECTIVE: Here, we used multiphoton-excited, 3-dimensional printing (MPE-3DP) to generate a native-like, extracellular matrix (ECM) scaffold with submicron resolution, and then seeded the scaffold with cardiomyocytes (CMs), smooth-muscle cells (SMCs), and endothelial cells (ECs) that had been differentiated from human induced-pluripotent stem cells (iPSCs) to generate a human, iPSC-derived cardiac muscle patch (hCMP), which was subsequently evaluated in a murine model of myocardial infarction (MI)...
January 9, 2017: Circulation Research
https://www.readbyqxmd.com/read/28064458/label-free-multiphoton-microscopy-reveals-altered-tissue-architecture-in-hippocampal-sclerosis
#5
Ortrud Uckermann, Roberta Galli, Susann Leupold, Roland Coras, Matthias Meinhardt, Susanne Hallmeyer-Elgner, Thomas Mayer, Alexander Storch, Gabriele Schackert, Edmund Koch, Ingmar Blümcke, Gerald Steiner, Matthias Kirsch
The properties and structure of tissue can be visualized without labeling or preparation by multiphoton microscopy combining coherent anti-Stokes Raman scattering (CARS), addressing lipid content, second harmonic generation (SHG) showing collagen, and two-photon excited fluorescence (TPEF) of endogenous fluorophores. We compared samples of sclerotic and nonsclerotic human hippocampus to detect pathologic changes in the brain of patients with pharmacoresistant temporomesial epilepsy (n = 15). Multiphoton microscopy of cryosections and bulk tissue revealed hippocampal layering and micromorphologic details in accordance with reference histology: CARS displayed white and gray matter layering and allowed the assessment of axonal myelin...
January 2017: Epilepsia
https://www.readbyqxmd.com/read/28063434/integral-steric-asymmetry-in-the-inelastic-scattering-of-no-x-2-%C3%AE
#6
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
#7
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
#8
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/28059176/spatially-localized-see-through-wall-temperature-measurements-in-a-flow-reactor-using-radar-rempi
#9
Yue Wu, Mark Gragston, Zhili Zhang, Joseph D Miller
See-through-wall coherent microwave scattering from resonance-enhanced multiphoton ionization (REMPI) for rotational temperature measurements of molecular oxygen has been developed and demonstrated in a flow reactor at atmospheric pressure. Through limited, single-ended optical access, a laser beam was focused to generate local ionization of molecular oxygen in a heated quartz flow reactor enclosed by ceramic heating elements. Coherent microwaves were transmitted, and the subsequent scattering off the laser-induced plasma was received, through the optically opaque ceramic heater walls and used to acquire rotational spectra of molecular oxygen and to determine temperature...
January 1, 2017: Optics Letters
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
#10
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/28050616/ligand-core-nlo-phores-a-combined-experimental-and-theoretical-approach-to-the-two-photon-absorption-and-two-photon-excited-emission-properties-of-small-ligated-silver-nanoclusters
#11
Isabelle Russier-Antoine, Franck Bertorelle, Nathalie Calin, Željka Sanader, Marjan Krstić, Clothilde Comby-Zerbino, Philippe Dugourd, Pierre-François Brevet, Vlasta Bonačić-Koutecký, Rodolphe Antoine
We report a combined experimental and theoretical study of the two-photon absorption and excited emission properties of monodisperse ligand stabilized Ag11, Ag15 and Ag31 nanoclusters in aqueous solutions. The nanoclusters were synthesized using a cyclic reduction under oxidative conditions and separated by vertical gel electrophoresis. The two-photon absorption cross-sections of these protected noble metal nanoclusters measured within the biologically attractive 750-900 nm window are several orders of magnitude larger than that reported for commercially available standard organic dyes...
January 19, 2017: Nanoscale
https://www.readbyqxmd.com/read/28043893/a-novel-microstructural-interpretation-for-the-biomechanics-of-mouse-skin-derived-from-multiscale-characterization
#12
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 setup 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
#13
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
https://www.readbyqxmd.com/read/28033468/enhancing-multiphoton-upconversion-from-nayf4-yb-tm-nayf4-core-shell-nanoparticles-via-the-use-of-laser-cavity
#14
Li Min Jin, Xian Chen, Chun Kit Siu, Feng Wang, Siu Fung Yu
We discover that emission efficiency of Tm(3+)-doped upconversion nanoparticles can be enhanced through the use of a laser cavity. With suitable control of the lasing conditions, the population of the intermediate excited states of the Tm(3+) can be clamped at a required value above the excitation threshold. As a result, upconversion efficiency for the 300-620 nm emission band of the Tm(3+)-doped nanoparticles under 976 nm excitation can be enhanced by an order of magnitude over the case without a laser cavity...
January 4, 2017: ACS Nano
https://www.readbyqxmd.com/read/28032121/direct-comparison-between-confocal-and-multiphoton-microscopy-for-rapid-histopathological-evaluation-of-unfixed-human-breast-tissue
#15
Tadayuki Yoshitake, Michael G Giacomelli, Lucas C Cahill, Daniel B Schmolze, Hilde Vardeh, Beverly E Faulkner-Jones, James L Connolly, James G Fujimoto
No abstract text is available yet for this article.
December 1, 2016: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28009209/decoupling-electronic-versus-nuclear-photoresponse-of-isolated-green-fluorescent-protein-chromophores-using-short-laser-pulses
#16
Hjalte V Kiefer, Henrik B Pedersen, Anastasia V Bochenkova, Lars H Andersen
The photophysics of a deprotonated model chromophore for the green fluorescent protein is studied by femtosecond laser pulses in an electrostatic ion-storage ring. The laser-pulse duration is much shorter than the time for internal conversion, and, hence, contributions from sequential multiphoton absorption, typically encountered with ns-laser pulses, are avoided. Following single-photon excitation, the action-absorption maximum is shown to be shifted within the S_{0} to S_{1} band from its origin at about 490 to 450 nm, which is explained by the different photophysics involved in the detected action...
December 9, 2016: Physical Review Letters
https://www.readbyqxmd.com/read/27998729/in%C3%A2-vivo-imaging-of-inflamed-glomeruli-reveals-dynamics-of-neutrophil-extracellular-trap-formation-in-glomerular-capillaries
#17
Clare L V Westhorpe, James E Bayard, Kim M O'Sullivan, Pam Hall, Qiang Cheng, A Richard Kitching, Michael J Hickey
Neutrophil extracellular traps (NETs) have been documented in glomeruli of patients with glomerulonephritis. However, the dynamics of NET formation in the glomerulus and their functional contribution to acute glomerular injury are poorly understood. Herein, we used in vivo multiphoton microscopy to investigate NET formation in the acutely inflamed glomerulus. Glomerular inflammation was induced using an antibody against the glomerular basement membrane. After induction of glomerular inflammation, multiphoton microscopy revealed that approximately 20% of glomeruli contained structures composed of extracellular DNA within the capillaries...
December 17, 2016: American Journal of Pathology
https://www.readbyqxmd.com/read/27995952/photon-entanglement-through-brain-tissue
#18
Lingyan Shi, Enrique J Galvez, Robert R Alfano
Photon entanglement, the cornerstone of quantum correlations, provides a level of coherence that is not present in classical correlations. Harnessing it by study of its passage through organic matter may offer new possibilities for medical diagnosis technique. In this work, we study the preservation of photon entanglement in polarization, created by spontaneous parametric down-conversion, after one entangled photon propagates through multiphoton-scattering brain tissue slices with different thickness. The Tangle-Entropy (TS) plots show the strong preservation of entanglement of photons propagating in brain tissue...
December 20, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27992081/non-invasive-metabolic-imaging-of-melanoma-progression
#19
Michael N Pastore, Hauke Studier, Claudine S Bonder, Michael S Roberts
Skin cancer is associated with abnormal cellular metabolism which if identified early introduces the possibility of intervention to prevent its progress to a deadly metastatic stage. This study combines multiphoton microscopy with fluorescence lifetime imaging (FLIM) using an syngeneic melanoma mouse model, to detect changes in metabolic state of single epidermal cells as a metabolic marker to monitor the progress of tumor growth. This method utilizes imaging of the ratio of the amounts of the free and protein-bound forms of the intracellular autofluorescent metabolic co-enzyme nicotinamide adenine dinucleotide (NADH)...
December 19, 2016: Experimental Dermatology
https://www.readbyqxmd.com/read/27991861/astrocytic-calcium-release-mediates-peri-infarct-depolarizations-in-a-rodent-stroke-model
#20
Cordula Rakers, Gabor C Petzold
Stroke is one of the most common diseases and a leading cause of death and disability. Cessation of cerebral blood flow (CBF) leads to cell death in the infarct core, but tissue surrounding the core has the potential to recover if local reductions in CBF are restored. In these areas, detrimental peri-infarct depolarizations (PIDs) contribute to secondary infarct growth and negatively affect stroke outcome. However, the cellular pathways underlying PIDs have remained unclear. Here, we have used in vivo multiphoton microscopy, laser speckle imaging of CBF, and electrophysiological recordings in a mouse model of focal ischemia to demonstrate that PIDs are associated with a strong increase of intracellular calcium in astrocytes and neurons...
December 19, 2016: Journal of Clinical Investigation
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