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multiphoton imaging

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https://www.readbyqxmd.com/read/29770596/self-referenced-axial-chromatic-dispersion-measurement-in-multiphoton-microscopy-through-2-color-thg-imaging
#1
Yu Du, Ziwei Zhuang, Jiexing He, Hongji Liu, Ping Qiu, Ke Wang
With tunable excitation light, multiphoton microscopy (MPM) is widely used for imaging biological structures at subcellular resolution. Axial chromatic dispersion, present in virtually every transmissive optical system including the multiphoton microscope, leads to focal (and the resultant image) plane separation. Here we demonstrate experimentally a technique to measure the axial chromatic dispersion in a multiphoton microscope, using simultaneous 2-color third-harmonic generation (THG) imaging excited by a 2-color soliton source with tunable wavelength separation...
May 16, 2018: Journal of Biophotonics
https://www.readbyqxmd.com/read/29760990/spatial-and-temporal-identification-of-cerebral-infarctions-based-on-multiphoton-microscopic-imaging
#2
Shu Wang, Huiping Du, Bingbing Lin, Chenxi Liao, Xiaoqin Zhu, Xingfu Wang, Hong Chen, Shuangmu Zhuo, Liwei Jiang, Lianhuang Li, Haohua Tu, Jianxin Chen
Ischemic stroke is a leading cause of death and permanent disability worldwide. Middle cerebral artery occlusion (MCAO) of variable duration times could be anticipated to result in varying degrees of injury that evolve spatially over time. Therefore, investigations following strokes require information concerning the spatiotemporal dimensions of the ischemic core as well as of perilesional areas. In the present study, multiphoton microscopy (MPM) based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) was applied to image such pathophysiological events...
May 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29760989/fiber-based-tunable-repetition-rate-source-for-deep-tissue-two-photon-fluorescence-microscopy
#3
Kriti Charan, Bo Li, Mengran Wang, Charles P Lin, Chris Xu
Deep tissue multiphoton imaging requires high peak power to enhance signal and low average power to prevent thermal damage. Both goals can be advantageously achieved through laser repetition rate tuning instead of simply adjusting the average power. We show that the ideal repetition rate for deep two-photon imaging in the mouse brain is between 1 and 10 MHz, and we present a fiber-based source with an arbitrarily tunable repetition rate within this range. The performance of the new source is compared to a mode-locked Ti:Sapphire (Ti:S) laser for in vivo imaging of mouse brain vasculature...
May 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29733571/aggregation-induced-emission-aie-dots-emerging-theranostic-nanolights
#4
Guangxue Feng, Bin Liu
Theranostic nanolights refer to luminescent nanoparticles possessing both imaging and therapeutic functions. Their shape, size, surface functions, and optical properties can be precisely manipulated through integrated efforts of chemistry, materials, and nanotechnology for customized applications. When localized photons are used to activate both imaging and therapeutic functions such as photodynamic or photothermal therapy, these theranostic nanolights increase treatment efficacy with minimized damage to surrounding healthy tissues, which represents a promising noninvasive nanomedicine as compared to conventional theranostic approaches...
May 7, 2018: Accounts of Chemical Research
https://www.readbyqxmd.com/read/29726099/visualizing-oxidative-cellular-stress-induced-by-nanoparticles-in-the-subcytotoxic-range-using-fluorescence-lifetime-imaging
#5
Jens Balke, Pierre Volz, Falko Neumann, Robert Brodwolf, Alexander Wolf, Hannah Pischon, Moritz Radbruch, Lars Mundhenk, Achim D Gruber, Nan Ma, Ulrike Alexiev
Nanoparticles hold a great promise in biomedical science. However, due to their unique physical and chemical properties they can lead to overproduction of intracellular reactive oxygen species (ROS). As an important mechanism of nanotoxicity, there is a great need for sensitive and high-throughput adaptable single-cell ROS detection methods. Here, fluorescence lifetime imaging microscopy (FLIM) is employed for single-cell ROS detection (FLIM-ROX) providing increased sensitivity and enabling high-throughput analysis in fixed and live cells...
May 4, 2018: Small
https://www.readbyqxmd.com/read/29716215/photodissociation-dynamics-of-propanal-and-isobutanal-the-norrish-type-i-pathway
#6
Aaron W Harrison, Scott H Kable
The Norrish Type I photodissociation of two aliphatic aldehydes, propanal and isobutanal, has been investigated using velocity-map imaging. The HCO photoproduct of this reaction was probed using a 1+1 resonance-enhanced multiphoton ionization scheme via the 3p2 Π Rydberg state. The velocity map images of HCO+ were collected across a range of photolysis energies for both species from 30 500 to 33 000 cm-1 (λ = 312-327 nm). The corresponding translational energy distributions show that the majority of the available energy goes into the translational motion of the products (55%-68%) with this fraction increasing as the T1 barrier is approached...
April 28, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29714485/why-do-silver-trimers-intercalated-in-dna-exhibit-unique-nonlinear-properties-that-are-promising-for-applications
#7
Vlasta Bonacic-Koutecky, Martina Perić, Zeljka Sanader
Our investigation of one-photon absorption (OPA) and nonlinear optical (NLO) properties such as two-photon absorption (TPA) of silver trimer intercalated in DNA based on TDDFT approach allowed us to propose mechanism responsible for large TPA cross sections of such NLO-phores. We present concept which illustrates key role of quantum cluster as well as of nucleotide bases from immediate neighborhood. For this purpose, different surroundings consisting of Guanine-Cytosine and Adenine-Thymine such as (GCGC) and (ATAT) have been investigated which are exhibiting substantially different values of TPA cross sections...
May 1, 2018: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29705743/-in-vivo-visualisation-of-different-modes-of-action-of-biological-dmards-inhibiting-osteoclastic-bone-resorption
#8
Yoshinobu Matsuura, Junichi Kikuta, Yuika Kishi, Tetsuo Hasegawa, Daisuke Okuzaki, Toru Hirano, Masafumi Minoshima, Kazuya Kikuchi, Atsushi Kumanogoh, Masaru Ishii
OBJECTIVES: Osteoclasts play critical roles in inflammatory bone destruction. Precursor cell migration, cell differentiation, and functional cell activation are all in play. Biological disease-modifying antirheumatic drugs (DMARDs) have been shown to significantly inhibit both bone erosion as well as synovitis, although how such agents reduce osteoclastic bone destruction in vivo has not been fully explained. Here, we used an intravital time-lapse imaging technique to directly visualise mature osteoclasts and their precursors, and explored how different biological DMARDs acted in vivo ...
April 28, 2018: Annals of the Rheumatic Diseases
https://www.readbyqxmd.com/read/29676795/application-of-a-reflective-microscope-objective-for-multiphoton-microscopy
#9
Mohammad M Kabir, Aakash M Choubal, Kimani C Toussaint
Reflective objectives (ROs) mitigate chromatic aberration across a broad wavelength range. Yet, a systematic performance characterisation of ROs has not been done. In this paper, we compare the performance of a 0.5 numerical-aperture (NA) reflective objective (RO) with a 0.55 NA standard glass objective (SO), using two-photon fluorescence (TPF) and second-harmonic generation (SHG). For experiments spanning ∼1 octave in the visible and NIR wavelengths, the SO leads to defocusing errors of 25-40% for TPF images of subdiffraction fluorescent beads and 10-12% for SHG images of collagen fibres...
April 20, 2018: Journal of Microscopy
https://www.readbyqxmd.com/read/29675306/super-resolution-fluorescence-microscopy-by-stepwise-optical-saturation
#10
Yide Zhang, Prakash D Nallathamby, Genevieve D Vigil, Aamir A Khan, Devon E Mason, Joel D Boerckel, Ryan K Roeder, Scott S Howard
Super-resolution fluorescence microscopy is an important tool in biomedical research for its ability to discern features smaller than the diffraction limit. However, due to its difficult implementation and high cost, the super-resolution microscopy is not feasible in many applications. In this paper, we propose and demonstrate a saturation-based super-resolution fluorescence microscopy technique that can be easily implemented and requires neither additional hardware nor complex post-processing. The method is based on the principle of stepwise optical saturation (SOS), where M steps of raw fluorescence images are linearly combined to generate an image with a [Formula: see text]-fold increase in resolution compared with conventional diffraction-limited images...
April 1, 2018: Biomedical Optics Express
https://www.readbyqxmd.com/read/29652604/an-engineered-human-adipose-collagen-model-for-in-vitro-breast-cancer-cell-migration-studies
#11
Robert David Hume, Lorraine Berry, Stefanie Reichelt, Michael D'Angelo, Jenny Gomm, Ruth Elizabeth Cameron, Christine Watson
Adipocytes are one of the major stromal cell components of the human breast. These cells play a key role in the development of the gland and are implicated in breast tumorigenesis. Frequently, directional stromal collagen I fibres are found surrounding aggressive breast tumours. These fibres enhance breast cancer cell migration and are associated with poor patient prognosis. We sought to recapitulate these stromal components in vitro to provide a 3D model comprising human adipose tissue and anisotropic collagen fibres...
March 8, 2018: Tissue Engineering. Part A
https://www.readbyqxmd.com/read/29643223/nerve-regeneration-in-the-cephalopod-mollusc-octopus-vulgaris-label-free-multiphoton-microscopy-as-a-tool-for-investigation
#12
Pamela Imperadore, Ortrud Uckermann, Roberta Galli, Gerald Steiner, Matthias Kirsch, Graziano Fiorito
Octopus and cephalopods are able to regenerate injured tissues. Recent advancements in the study of regeneration in cephalopods appear promising encompassing different approaches helping to decipher cellular and molecular machinery involved in the process. However, lack of specific markers to investigate degenerative/regenerative phenomena and inflammatory events occurring after damage is limiting these studies. Label-free multiphoton microscopy is applied for the first time to the transected pallial nerve of Octopus vulgaris Various optical contrast methods including coherent anti-Stokes Raman scattering (CARS), endogenous two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) have been used...
April 2018: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/29629958/guanylyl-cyclase-a-in-both-renal-proximal-tubular-and-vascular-endothelial-cells-protects-the-kidney-against-acute-injury-in-rodent-experimental-endotoxemia-models
#13
Hiroaki Kitamura, Daisuke Nakano, Yoshiharu Sawanobori, Takehiko Asaga, Hideki Yokoi, Motoko Yanagita, Masashi Mukoyama, Takeshi Tokudome, Kenji Kangawa, Gotaro Shirakami, Akira Nishiyama
BACKGROUND: Natriuretic peptides are used, based on empirical observations, in intensive care units as antioliguric treatments. We hypothesized that natriuretic peptides prevent lipopolysaccharide-induced oliguria by activating guanylyl cyclase A, a receptor for natriuretic peptides, in proximal tubules and endothelial cells. METHODS: Normal Sprague-Dawley rats and mice lacking guanylyl cyclase A in either endothelial cells or proximal tubular cells were challenged with lipopolysaccharide and assessed for oliguria and intratubular flow rate by intravital imaging with multiphoton microscopy...
April 9, 2018: Anesthesiology
https://www.readbyqxmd.com/read/29626894/time-resolved-photoion-imaging-spectroscopy-determining-energy-distribution-in-multiphoton-absorption-experiments
#14
D B Qian, F D Shi, L Chen, S Martin, J Bernard, J Yang, S F Zhang, Z Q Chen, X L Zhu, X Ma
We propose an approach to determine the excitation energy distribution due to multiphoton absorption in the case of excited systems following decays to produce different ion species. This approach is based on the measurement of the time-resolved photoion position spectrum by using velocity map imaging spectrometry and an unfocused laser beam with a low fluence and homogeneous profile. Such a measurement allows us to identify the species and the origin of each ion detected and to depict the energy distribution using a pure Poisson's equation involving only one variable which is proportional to the absolute photon absorption cross section...
April 7, 2018: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29619204/the-harpooning-mechanism-as-evidenced-in-the-oxidation-reaction-of-the-al-atom
#15
Fangfang Li, Changwu Dong, Jun Chen, Jiaxing Liu, Fengyan Wang, Xin Xu
The harpooning mechanism has long been proposed for elementary reaction dynamics involving metals. It is characterized by an initial electron transfer (ET) process from the metal to the oxidant molecule. For the titled reaction Al + O2 , the ET distance can be predicted to be 2.6 Å by simply calculating the energy difference between the ionization energy of the Al atom and the electron affinity of the O2 molecule. Hereby we experimentally derived the maximum impact parameter b max of 2.5 ± 0.2 Å for the titled reaction, in consistency with the predicted ET distance...
January 14, 2018: Chemical Science
https://www.readbyqxmd.com/read/29615678/protein-bound-nad-p-h-lifetime-is-sensitive-to-multiple-fates-of-glucose-carbon
#16
Joe T Sharick, Peter F Favreau, Amani A Gillette, Sophia M Sdao, Matthew J Merrins, Melissa C Skala
While NAD(P)H fluorescence lifetime imaging (FLIM) can detect changes in flux through the TCA cycle and electron transport chain (ETC), it remains unclear whether NAD(P)H FLIM is sensitive to other potential fates of glucose. Glucose carbon can be diverted from mitochondria by the pentose phosphate pathway (via glucose 6-phosphate dehydrogenase, G6PDH), lactate production (via lactate dehydrogenase, LDH), and rejection of carbon from the TCA cycle (via pyruvate dehydrogenase kinase, PDK), all of which can be upregulated in cancer cells...
April 3, 2018: Scientific Reports
https://www.readbyqxmd.com/read/29615099/multimodal-label-free-imaging-of-living-dermal-equivalents-including-dermal-papilla-cells
#17
Aleksandra V Meleshina, Olga S Rogovaya, Varvara V Dudenkova, Marina A Sirotkina, Maria M Lukina, Alena S Bystrova, Victoria G Krut, Daria S Kuznetsova, Ekaterina P Kalabusheva, Andrey V Vasiliev, Ekaterina A Vorotelyak, Elena V Zagaynova
BACKGROUND: Despite the significant progress in the development of skin equivalents (SEs), the problem of noninvasively assessing the quality of the cell components and the collagen structure of living SEs both before and after transplantation remains. Undoubted preference is given to in vivo methods of noninvasive, label-free monitoring of the state of the SEs. Optical bioimaging methods, such as cross-polarization optical coherence tomography (CP OCT), multiphoton tomography (MPT), and fluorescence lifetime imaging microscopy (FLIM), present particular advantages for the visualization of such SEs...
April 3, 2018: Stem Cell Research & Therapy
https://www.readbyqxmd.com/read/29603649/ex-and-in-vivo-characterization-of-the-wavelength-dependent-3-photon-action-cross-sections-of-red-fluorescent-proteins-covering-the-1700-nm-window
#18
Hongji Liu, Jiaqi Wang, Xiao Peng, Ziwei Zhuang, Ping Qiu, Ke Wang
Multiphoton action cross sections are the prerequisite for excitation light selection. At the 1700-nm window suitable for deep-tissue imaging, wavelength-dependent 3-photon action cross sections ησ3 for RFPs are unknown, preventing wavelength selection. Here we demonstrate: (1) ex vivo measurement of wavelength-dependent ησ3 for purified RFPs; (2) a multiphoton imaging guided measurement system for in vivo measurement; and (3) in vivo measurement of wavelength-dependent ησ3 in RFP labeled cells. These fundamental results will provide guidelines for excitation wavelength selection for 3-photon fluorescence imaging of RFPs at the 1700-nm window, and augment the existing database of multiphoton action cross sections for fluorophores...
March 30, 2018: Journal of Biophotonics
https://www.readbyqxmd.com/read/29600858/imaging-the-dynamics-of-ch-2-bri-photodissociation-in-the-near-ultraviolet-region
#19
Changen Pan, Yi Zhang, Joseph D Lee, Nathanael M Kidwell
The photodissociation dynamics of jet-cooled CH2 BrI are investigated in the near-ultraviolet (UV) region from 280 - 310 nm using velocity map imaging. We report the translational and internal energy distributions of the CH2 Br radical and ground state I (2 P3/2 ) or spin-orbit excited I (2 P1/2 ) fragments determined by velocity map imaging of the ionized iodine fragments following 2+1 resonance-enhanced multiphoton ionization of the nascent neutral iodine products. The velocity distributions indicate that most of the available energy is partitioned into the internal energy of the CH2 Br radical with only modest translational excitation imparted to the co-fragments, which is consistent with a simple impulsive model...
March 30, 2018: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/29594837/diagnosing-pituitary-adenoma-in-unstained-sections-based-on-multiphoton-microscopy
#20
Peihua Lin, Xueyong Liu, Shu Wang, Xiaoling Li, Yankun Song, Lianhuang Li, Shanshan Cai, Xingfu Wang, Jianxin Chen
PURPOSE: If we can find a new method that can achieve rapid diagnosis of adenoma during operation, it will help surgeon shorten the operation time and enhance the treatment efficacy. This study discusses the feasibility of multiphoton microscopy (MPM) in diagnosing pituitary adenoma. METHOD: MPM, based on two-photon excited fluorescence (TPEF) and second harmonic generation (SHG) is performed for the diagnosis of pituitary adenoma in unstained sections. RESULTS: Our results show that MPM can reveal the variation of reticulin fiber by SHG signals of collagen, combined with the measurement of area of acinus, thickness of collagen fiber and collagen percentage...
March 29, 2018: Pituitary
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