Read by QxMD icon Read


Christopher K Arakawa, Barry A Badeau, Ying Zheng, Cole A DeForest
A photodegradable material-based approach to generate endothelialized 3D vascular networks within cell-laden hydrogel biomaterials is introduced. Exploiting multiphoton lithography, microchannel networks spanning nearly all size scales of native human vasculature are readily generated with unprecedented user-defined 4D control. Intraluminal channel architectures of synthetic vessels are fully customizable, providing new opportunities for next-generation microfluidics and directed cell function.
July 24, 2017: Advanced Materials
Ruben M Sandoval, Bruce A Molitoris
The kidney is a complex and dynamic organ with over 40 cell types, and tremendous structural and functional diversity. Intravital multi-photon microscopy, development of fluorescent probes and innovative software, have rapidly advanced the study of intracellular and intercellular processes within the kidney. Researchers can quantify the distribution, behavior, and dynamic interactions of up to four labeled chemical probes and proteins simultaneously and repeatedly in four dimensions (time), with subcellular resolution in near real time...
July 18, 2017: Methods: a Companion to Methods in Enzymology
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
G Barratt Park, Bastian C Krüger, Sven Meyer, Alexander Kandratsenka, Alec M Wodtke, Tim Schäfer
The conversion of translational to rotational motion often plays a major role in the trapping of small molecules at surfaces, a crucial first step for a wide variety chemical processes that occur at gas-surface interfaces. However, to date most quantum-state resolved surface scattering experiments have been performed on diatomic molecules, and little detailed information is available about how the structure of nonlinear polyatomic molecules influences the mechanisms for energy exchange with surfaces. In the current work, we employ a new rotationally resolved 1 + 1' resonance-enhanced multiphoton ionization (REMPI) scheme to measure the rotational distribution in formaldehyde molecules directly scattered from the Au(111) surface at incidence kinetic energies in the range 0...
July 20, 2017: Physical Chemistry Chemical Physics: PCCP
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
A Bunjac, D B Popović, N S Simonović
A method for determining the resonant dynamic Stark shift (RDSS), based on wave-packet calculations of the populations of quantum states, is presented. It is almost insensitive to variations of the laser pulse profile, and this feature ensures generality in applications. This method is used to determine an RDSS data set for 3s → nl (n ≤ 6) transitions in sodium induced by laser pulses with peak intensities up to 7.9 × 10(12) W cm(-2) and wavelengths in the range from 455.6 to 1139 nm. The data are applied to analyze the photoelectron spectra (electron yield versus excess energy) of the sodium atom interacting with 800 nm laser radiation...
July 18, 2017: Physical Chemistry Chemical Physics: PCCP
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
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
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
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
Stefanie Diermeier, Andreas Buttgereit, Sebastian Schürmann, Lilli Winter, Hongyang Xu, Robyn M Murphy, Christoph S Clemen, Rolf Schröder, Oliver Friedrich
The majority of hereditary and acquired myopathies are clinically characterized by progressive muscle weakness. We hypothesized that ongoing derangement of skeletal muscle cytoarchitecture at the single fiber level may precede and be responsible for the progressive muscle weakness. Here, we analyzed the effects of aging in wild-type (wt) and heterozygous (het) and homozygous (hom) R349P desmin knock-in mice. The latter harbor the ortholog of the most frequently encountered human R350P desmin missense mutation...
June 13, 2017: Neurobiology of Aging
Nicholas B Borotto, Phillip J McClory, Brent R Martin, Kristina Hakansson
Protein S-sulfinylation (R-SO2-) and S-sulfonylation (R-SO3-) are irreversible oxidative post-translational modifications of cysteine residues. Greater than 5% of cysteines are reported to occupy these higher oxidation states, which effectively inac-tivate the corresponding thiols and alter the electronic and physical properties of modified proteins. Such higher oxidation states are reached after excessive exposure to cellular oxidants, and accumulate across different disease states. Despite widespread and functionally relevant cysteine oxidation across the proteome, there are currently no robust methods to pro-file higher order cysteine oxidation...
July 14, 2017: Analytical Chemistry
Sheng-Ping Liang, I-Chung Lu, Shang-Ting Tsai, Jien-Lian Chen, Yuan Tseh Lee, Chi-Kung Ni
Ultraviolet laser pulses at 355 nm with variable pulse widths in the region from 170 ps to 1.5 ns were used to investigate the ionization mechanism of matrix-assisted laser desorption/ionization (MALDI) for matrices 2,5-dihydroxybenzoic acid (DHB), α-cyano-4-hydroxycinnamic acid (CHCA), and sinapinic acid (SA). The mass spectra of desorbed ions and the intensity and velocity distribution of desorbed neutrals were measured simultaneously for each laser shot. These quantities were found to be independent of the laser pulse width...
July 13, 2017: Journal of the American Society for Mass Spectrometry
Anton Frisk Kockum, Vincenzo Macrì, Luigi Garziano, Salvatore Savasta, Franco Nori
We propose a new method for frequency conversion of photons which is both versatile and deterministic. We show that a system with two resonators ultrastrongly coupled to a single qubit can be used to realise both single- and multiphoton frequency-conversion processes. The conversion can be exquisitely controlled by tuning the qubit frequency to bring the desired frequency-conversion transitions on or off resonance. Considering recent experimental advances in ultrastrong coupling for circuit QED and other systems, we believe that our scheme can be implemented using available technology...
July 13, 2017: Scientific Reports
M Müller, H Vural, C Schneider, A Rastelli, O G Schmidt, S Höfling, P Michler
Multiphoton entangled states such as "N00N states" have attracted a lot of attention because of their possible application in high-precision, quantum enhanced phase determination. So far, N00N states have been generated in spontaneous parametric down-conversion processes and by mixing quantum and classical light on a beam splitter. Here, in contrast, we demonstrate superresolving phase measurements based on two-photon N00N states generated by quantum dot single-photon sources making use of the Hong-Ou-Mandel effect on a beam splitter...
June 23, 2017: Physical Review Letters
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
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
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
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
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
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"