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https://www.readbyqxmd.com/read/28541708/highly-stable-monocrystalline-silver-clusters-for-plasmonic-applications
#1
Sergey M Novikov, Vladimir N Popok, Andrey B Evlyukhin, Muhammad Hanif, Per Morgen, Jacek Fiutowski, Jonas Beermann, Horst-Guenter Rubahn, Sergey I Bozhevolnyi
: Plasmonics sensor configurations utilizing localized plasmon resonances in silver nanostructures typically suffer from rapid degradation of silver in ambient atmospheric conditions. In this work, we report on the fabrication and detailed characterization of ensembles of monocrystalline silver nanoparticles (NPs), which exhibit a long-term stability of optical properties under ambient conditions without any protective treatments. Ensembles with different densities (surface coverages) of size-selected NPs (diameters from 12...
May 25, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
https://www.readbyqxmd.com/read/28538834/characteristics-of-liver-fibrosis-with-different-etiologies-using-a-fully-quantitative-fibrosis-assessment-tool
#2
Q Wu, X Zhao, H You
This study aimed to test the diagnostic performance of a fully quantitative fibrosis assessment tool for liver fibrosis in patients with chronic hepatitis B (CHB), primary biliary cirrhosis (PBC) and non-alcoholic steatohepatitis (NASH). A total of 117 patients with liver fibrosis were included in this study, including 50 patients with CHB, 49 patients with PBC and 18 patients with NASH. All patients underwent liver biopsy (LB). Fibrosis stages were assessed by two experienced pathologists. Histopathological images of LB slices were processed by second harmonic generation (SHG)/two-photon excited fluorescence (TPEF) microscopy without staining, a system called qFibrosis (quantitative fibrosis) system...
May 18, 2017: Brazilian Journal of Medical and Biological Research, Revista Brasileira de Pesquisas Médicas e Biológicas
https://www.readbyqxmd.com/read/28534042/loss-of-the-habenula-intrinsic-neuromodulator-kisspeptin1-affects-learning-in-larval-zebrafish
#3
Charlotte Lupton, Mohini Sengupta, Ruey-Kuang Cheng, Joanne Chia, Vatsala Thirumalai, Suresh Jesuthasan
Learning how to actively avoid a predictable threat involves two steps: recognizing the cue that predicts upcoming punishment and learning a behavioral response that will lead to avoidance. In zebrafish, ventral habenula (vHb) neurons have been proposed to participate in both steps by encoding the expected aversiveness of a stimulus. vHb neurons increase their firing rate as expectation of punishment grows but reduce their activity as avoidance learning occurs. This leads to changes in the activity of raphe neurons, which are downstream of the vHb, during learning...
May 2017: ENeuro
https://www.readbyqxmd.com/read/28532358/experience-dependent-structural-plasticity-in-the-visual-system
#4
Kalen P Berry, Elly Nedivi
During development, the environment exerts a profound influence on the wiring of brain circuits. Due to the limited resolution of studies in fixed tissue, this experience-dependent structural plasticity was once thought to be restricted to a specific developmental time window. The recent introduction of two-photon microscopy for in vivo imaging has opened the door to repeated monitoring of individual neurons and the study of structural plasticity mechanisms at a very fine scale. In this review, we focus on recent work showing that synaptic structural rearrangements are a key mechanism mediating neural circuit adaptation and behavioral plasticity in the adult brain...
October 14, 2016: Annual Review of Vision Science
https://www.readbyqxmd.com/read/28531846/synthesis-characterization-and-nonlinear-optical-nlo-properties-of-truxene-cored-diphenylamine-derivatives
#5
Fusheng Li, Baodong Zhao, Yu Chen, Yufei Zhang, Tao Wang, Song Xue
Three star-shaped compounds based on a truxene core (FS11, FS12 and FS13) were prepared. The truxene core is incorporating with asymmetric diphenylamines, including one phenyl of diphenylamine substituted by methoxy group and the other phenyl substituted by tolyl, fluorophenyl and phenylethynyl for FS11, FS12 and FS13, respectively. Their one-photon, two-photon absorption, geometric structures, electrochemical behavior and thermal properties were investigated. The absorption maxima of charge transfer band for FS11, FS12 and FS13 are 375nm, 373nm and 383nm, and the corresponding molar extinction coefficients of FS11, FS12 and FS13 is 79,950M(-1)cm(-1), 67,220M(-1)cm(-1) and 108,780M(-1)cm(-1)...
May 15, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28530831/blue-shifted-green-fluorescent-protein-homologues-are-brighter-than-enhanced-green-fluorescent-protein-under-two-photon-excitation
#6
Rosana S Molina, Tam M Tran, Robert E Campbell, Gerard G Lambert, Anya Salih, Nathan C Shaner, Thomas E Hughes, Mikhail Drobizhev
Fluorescent proteins (FPs) are indispensable markers for two-photon imaging of live tissue, especially in the brains of small model organisms. The quantity of physiologically relevant data collected, however, is limited by heat-induced damage of the tissue due to the high intensities of the excitation laser. We seek to minimize this damage by developing FPs with improved brightness. Among FPs with the same chromophore structure, the spectral properties can vary widely due to differences in the local protein environment...
May 25, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/28530726/surface-enhanced-hyper-raman-scattering-sehrs-and-its-applications
#7
REVIEW
Fani Madzharova, Zsuzsanna Heiner, Janina Kneipp
Surface enhanced hyper Raman scattering (SEHRS) is the spontaneous, two-photon excited Raman scattering that occurs for molecules residing in high local optical fields of plasmonic nanostructures. Being regarded as a non-linear analogue of surface enhanced Raman scattering (SERS), SEHRS shares most of its properties, but also has additional characteristics. They include complementary spectroscopic information resulting from different selection rules and a stronger enhancement due to the non-linearity in excitation...
May 22, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28530551/angular-velocity-integration-in-a-fly-heading-circuit
#8
Daniel Turner-Evans, Stephanie Wegener, Hervé Rouault, Romain Franconville, Tanya Wolff, Johannes D Seelig, Shaul Druckmann, Vivek Jayaraman
Many animals maintain an internal representation of their heading as they move through their surroundings. Such a compass representation was recently discovered in a neural population in the Drosophila melanogaster central complex, a brain region implicated in spatial navigation. Here, we use two-photon calcium imaging and electrophysiology in head-fixed walking flies to identify a different neural population that conjunctively encodes heading and angular velocity, and is excited selectively by turns in either the clockwise or counterclockwise direction...
May 22, 2017: ELife
https://www.readbyqxmd.com/read/28530280/visualization-of-vesicular-transport-from-the-endoplasmic-reticulum-to-lysosome-using-an-amidine-derived-two-photon-probe
#9
Hyo Won Lee, Myoung Ki Cho, Hye-Ri Kim, Chang Su Lim, Chulhun Kang, Hwan Myung Kim
We report an amidine-based small molecule two-photon fluorescent probe (ELP1) for monitoring vesicle transport from the ER to lysosome in live cells. Two-photon microscopy imaging studies indicated that this probe initially localized in the ER and subsequently transferred to lysosomal compartments through vesicular transport. These results may provide an effective tool for studying trafficking-related biology and pathology in real-time.
May 22, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28530270/two-photon-photoelectron-emission-microscopy-for-surface-plasmon-polaritons-at-the-au-111-surface-decorated-with-alkanethiolate-self-assembled-monolayers
#10
Kana Yamagiwa, Masahiro Shibuta, Atsushi Nakajima
In this study, we have employed dual-color photoelectron emission microscopy (2P-PEEM) to visualize surface plasmon polaritons (SPPs) propagating along a chemically modified organic/metal interface of alkanethiolate self-assembled monolayers (Cn-SAMs; n is the number of alkyl carbon atoms) formed on Au(111). In dual-color 2P-PEEM, near-infrared photons around 900 nm generate SPPs at the Cn-SAMs/Au(111) interface, which interfere with the remaining light field. The resulting surface polarization beats are imaged as local distributions of 2P-photoelectrons probed by ultraviolet photons...
May 22, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28530008/field-strength-and-frequency-tunable-two-way-rotation-of-liquid-crystal-micro-particles-dispersed-in-a-liquid-crystal-host
#11
Koki Imamura, Hiroyuki Yoshida, Masanori Ozaki
Liquid crystal (LC) micro-particles are functional materials possessing anisotropies of LCs originating from their inner molecular alignment, and are fabricated by polymerizing pre-aligned rod-like molecules in the LC state. Here we demonstrate field strength and frequency tunable two-way rotation control of LC micro-particles in a LC host, and unravel its mechanism by theoretically calculating the contributing free energies. Cuboid-shaped micro-particles with inner molecular alignment along the long axis are fabricated via two-photon excited direct laser writing, and dispersed in a dual-frequency (DF) LC to be electrically driven by a voltage applied in the in-plane direction of the cell...
May 22, 2017: Soft Matter
https://www.readbyqxmd.com/read/28529673/on-chip-two-photon-metabolic-imaging-for-drug-toxicity-testing
#12
Fang Yu, Shuangmu Zhuo, Yinghua Qu, Deepak Choudhury, Zhiping Wang, Ciprian Iliescu, Hanry Yu
We have developed a microfluidic system suitable to be incorporated with a metabolic imaging method to monitor the drug response of cells cultured on a chip. The cells were perfusion-cultured to mimic the blood flow in vivo. Label-free optical measurements and imaging of nicotinamide adenine dinucleotide and flavin adenine dinucleotide fluorescence intensity and morphological changes were evaluated non-invasively. Drug responses calculated using redox ratio imaging were compared with the drug toxicity testing results obtained with a traditional well-plate system...
May 2017: Biomicrofluidics
https://www.readbyqxmd.com/read/28529642/tumor-triggered-drug-release-from-calcium-carbonate-encapsulated-gold-nanostars-for-near-infrared-photodynamic-photothermal-combination-antitumor-therapy
#13
Yanlei Liu, Xiao Zhi, Meng Yang, Jingpu Zhang, Lingnan Lin, Xin Zhao, Wenxiu Hou, Chunlei Zhang, Qian Zhang, Fei Pan, Gabriel Alfranca, Yuming Yang, Jesús M de la Fuente, Jian Ni, Daxiang Cui
Different stimulus including pH, light and temperature have been used for controlled drug release to prevent drug inactivation and minimize side-effects. Herein a novel nano-platform (GNS@CaCO3/ICG) consisting of calcium carbonate-encapsulated gold nanostars loaded with ICG was established to couple the photothermal properties of gold nanostars (GNSs) and the photodynamic properties of indocyanine green (ICG) in the photodynamic/photothermal combination therapy (PDT/PTT). In this study, the calcium carbonate worked not only a drug keeper to entrap ICG on the surface of GNSs in the form of a stable aggregate which was protected from blood clearance, but also as the a pH-responder to achieve highly effective tumor-triggered drug release locally...
2017: Theranostics
https://www.readbyqxmd.com/read/28528636/correlative-two-photon-and-serial-block-face-scanning-electron-microscopy-in-neuronal-tissue-using-3d-near-infrared-branding-maps
#14
Robert M Lees, Christopher J Peddie, Lucy M Collinson, Michael C Ashby, Paul Verkade
Linking cellular structure and function has always been a key goal of microscopy, but obtaining high resolution spatial and temporal information from the same specimen is a fundamental challenge. Two-photon (2P) microscopy allows imaging deep inside intact tissue, bringing great insight into the structural and functional dynamics of cells in their physiological environment. At the nanoscale, the complex ultrastructure of a cell's environment in tissue can be reconstructed in three dimensions (3D) using serial block face scanning electron microscopy (SBF-SEM)...
2017: Methods in Cell Biology
https://www.readbyqxmd.com/read/28528255/molecular-structure-second-and-third-order-nonlinear-optical-properties-and-dft-studies-of-a-novel-non-centrosymmetric-chalcone-derivative-2e-3-4-fluorophenyl-1-4-1e-4-fluorophenyl-methylene-amino-phenyl-prop-2-en-1-one
#15
Shivaraj R Maidur, Parutagouda Shankaragouda Patil, Anusha Ekbote, Tze Shyang Chia, Ching Kheng Quah
In the present work, the title chalcone, (2E)-3-(4-fluorophenyl)-1-(4-{[(1E)-(4-fluorophenyl) methylene]amino}phenyl)prop-2-en-1-one (abbreviated as FAMFC), was synthesized and structurally characterized by single-crystal X-ray diffraction. The compound is crystallized in the monoclinic system with non-centrosymmetric space group P21 and hence it satisfies the essential condition for materials to exhibit second-order nonlinear optical properties. The molecular structure was further confirmed by using FT-IR and (1)H NMR spectroscopic techniques...
May 9, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
https://www.readbyqxmd.com/read/28527966/suture-dehiscence-in-the-tricuspid-annulus-an-ex%C3%A2-vivo-analysis-of-tissue-strength-and-composition
#16
Deborah M Paul, Ajay Naran, Eric L Pierce, Charles H Bloodworth, Steven F Bolling, Ajit P Yoganathan
BACKGROUND: Surgical repair of functional tricuspid regurgitation (FTR) is an increasingly common practice, but annuloplasty suture dehiscence remains a significant problem. Quantitative and mechanistic understanding of annular suture holding strength can support more effective techniques for tricuspid valve device anchoring. METHODS: Suture holding strength of ovine tricuspid annuli (n = 15) was quantified ex vivo by pullout testing at 12 positions around their circumference...
May 17, 2017: Annals of Thoracic Surgery
https://www.readbyqxmd.com/read/28526891/hanbury-brown-twiss-effect-without-two-photon-interference-in-photon-counting-regime
#17
Bin Bai, Yu Zhou, Ruifeng Liu, Huaibin Zheng, Yunlong Wang, Fuli Li, Zhuo Xu
From quantum point of view, Hanbury Brown-Twiss effect is a result of constructive-destructive two-photon interference. There should be no Hanbury Brown-Twiss effect if there was no two-photon interference. In this paper, we observed Hanbury Brown- Twiss effect in a specially designed experiment, in which two-photon interference is impossible by keeping only one two-photon probability amplitude in the experimental scheme. However, our experimental results can still be interpreted by Glauber's quantum optical coherence theory...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28526883/openspritzer-an-open-hardware-pressure-ejection-system-for-reliably-delivering-picolitre-volumes
#18
C J Forman, H Tomes, B Mbobo, R J Burman, M Jacobs, T Baden, J V Raimondo
The ability to reliably and precisely deliver picolitre volumes is an important component of biological research. Here we describe a high-performance, low-cost, open hardware pressure ejection system (Openspritzer), which can be constructed from off the shelf components. The device is capable of delivering minute doses of reagents to a wide range of biological and chemical systems. In this work, we characterise the performance of the device and compare it to a popular commercial system using two-photon fluorescence microscopy...
May 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28523936/experimental-spectroscopic-studies-of-carbon-monoxide-co-fluorescence-at-high-temperatures-and-pressures
#19
Olivier Carrivain, Mikael Orain, Nelly Dorval, Celine Morin, Guillaume Legros
Two-photon excitation laser-induced fluorescence of carbon monoxide (CO-LIF) is investigated experimentally in order to determine the applicability of this technique for imaging CO concentration in aeronautical combustors. Experiments are carried out in a high temperature, high-pressure test cell, and in a laminar premixed CH4/air flame. Influence of temperature and pressure on CO-LIF spectra intensity and shape is reported. The experimental results show that as pressure increases, the CO-LIF excitation spectrum becomes asymmetric...
January 1, 2017: Applied Spectroscopy
https://www.readbyqxmd.com/read/28522470/three-dimensional-ca-2-imaging-advances-understanding-of-astrocyte-biology
#20
Erika Bindocci, Iaroslav Savtchouk, Nicolas Liaudet, Denise Becker, Giovanni Carriero, Andrea Volterra
Astrocyte communication is typically studied by two-dimensional calcium ion (Ca(2+)) imaging, but this method has not yielded conclusive data on the role of astrocytes in synaptic and vascular function. We developed a three-dimensional two-photon imaging approach and studied Ca(2+) dynamics in entire astrocyte volumes, including during axon-astrocyte interactions. In both awake mice and brain slices, we found that Ca(2+) activity in an individual astrocyte is scattered throughout the cell, largely compartmented between regions, preponderantly local within regions, and heterogeneously distributed regionally and locally...
May 19, 2017: Science
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