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https://www.readbyqxmd.com/read/28211922/applying-phasor-approach-analysis-of-multiphoton-flim-measurements-to-probe-the-metabolic-activity-of-three-dimensional-in-vitro-cell-culture-models
#1
Pirmin H Lakner, Michael G Monaghan, Yvonne Möller, Monilola A Olayioye, Katja Schenke-Layland
Fluorescence lifetime imaging microscopy (FLIM) can measure and discriminate endogenous fluorophores present in biological samples. This study seeks to identify FLIM as a suitable method to non-invasively detect a shift in cellular metabolic activity towards glycolysis or oxidative phosphorylation in 3D Caco-2 models of colorectal carcinoma. These models were treated with potassium cyanide or hydrogen peroxide as controls, and epidermal growth factor (EGF) as a physiologically-relevant influencer of cell metabolic behaviour...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28211728/electron-vortices-in-femtosecond-multiphoton-ionization
#2
D Pengel, S Kerbstadt, D Johannmeyer, L Englert, T Bayer, M Wollenhaupt
Multiphoton ionization of potassium atoms with a sequence of two counter-rotating circularly polarized femtosecond laser pulses produces vortex-shaped photoelectron momentum distributions in the polarization plane describing Archimedean spirals. The pulse sequences are produced by polarization shaping and the three-dimensional photoelectron distributions are tomographically reconstructed from velocity map imaging measurements. We show that perturbative ionization leads to electron vortices with c_{6} rotational symmetry...
February 3, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28198734/new-frontiers-in-intravital-microscopy-of-the-kidney
#3
Andrew M Hall, Claus D Schuh, Dominik Haenni
PURPOSE OF REVIEW: Intravital imaging with multiphoton microscopy enables the detailed study of dynamic cellular processes within functioning organs in living animals, in ways that would not otherwise be possible. It therefore represents a powerful tool in translational kidney research. In this article, we will discuss several new technical developments that have significantly increased the capabilities of kidney imaging. RECENT FINDINGS: Important contemporary advances in biomedical imaging technology include longer wavelength excitation lasers, far-red emitting fluorescent reporters, highly sensitive detectors, fluorescence lifetime measurements, adaptive optics, microendoscopes, high-throughput automated analysis algorithms and tissue clearing techniques...
February 13, 2017: Current Opinion in Nephrology and Hypertension
https://www.readbyqxmd.com/read/28192967/direct-analysis-of-xanthine-stimulants-in-archaeological-vessels-by-laser-desorption-resonance-enhanced-multiphoton-ionization
#4
Shawn C Owens, Jacob A Berenbeim, Marshall R Ligare, Lisa E Gulian, Faady M Siouri, Samuel Boldissar, Stuart Tyson-Smith, Gregory Wilson, Anabel Ford, Mattanjah S de Vries
Resonance enhanced multiphoton ionization spectroscopy (REMPI) generates simultaneous vibronic spectroscopy and fragment free mass spectrometry to identify molecules within a complex matrix. We combined laser desorption with REMPI spectroscopy to study organic residues within pottery sherds from Maya vessels (600-900 CE) and Mississippian vessels (1100-1200 CE), successfully detecting three molecular markers, caffeine, theobromine, and theophylline, associated with the use of cacao. This analytical approach provides a high molecular specificity, based on both wavelength and mass identification...
February 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28192297/controlling-and-tracking-of-colloidal-nanostructures-through-two-photon-fluorescence
#5
Dipankar Mondal, Debabrata Goswami
Multiphoton absorbing dye-coated trapped spherical bead at the focal plane of femtosecond optical tweezers shows nonlinear optical (NLO) phenomena. One such NLO process of two-photon fluorescence (TPF) has been used for the background-free imaging of a femtosecond laser-trapping event. Due to the high peak powers of femtosecond laser pulses with low average powers, it is possible to not only trap single nanospheres, but encourage optically directed self-assembly. The TPF signatures of trapped particles show evidence of such a directed self-assembly process which, in turn, can provide information about the structural dynamics during the process of cluster formation...
October 7, 2016: Methods and Applications in Fluorescence
https://www.readbyqxmd.com/read/28185927/evidence-of-proteolipid-domain-formation-in-an-inner-mitochondrial-membrane-mimicking-model
#6
Mouhedine Cheniour, Jonathan Brewer, Luis Bagatolli, Olivier Marcillat, Thierry Granjon
BACKGROUND: Mitochondrial Creatine kinase (mtCK) is highly abundant in mitochondria; its quantity is equimolecular to the Adenylic Nucleotide Translocator and represents 1% of the mitochondrial proteins. It is a multitask protein localized in the mitochondria intermembrane space where it binds to the specific cardiolipin (CL) phospholipid. If mtCK was initially thought to be exclusively implicated in energy transfer between mitochondria and cytosol through a mechanism referred to as the phosphocreatine shuttle, several recent studies suggested an additional role in maintaining mitochondria membrane structure...
February 6, 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/28178583/detection-of-polycyclic-aromatic-hydrocarbons-pahs-in-medicago-sativa-l-by-fluorescence-microscopy
#7
Wilber S Alves, Evelin A Manoel, Noemi S Santos, Rosane O Nunes, Giselli C Domiciano, Marcia R Soares
Green technologies, such as phytoremediation, are effective for removing organic pollutants derived from oil and oil products, including polycyclic aromatic hydrocarbons (PAHs). Given the increasing popularity of these sustainable remediation techniques, methods based on fluorescence microscopy and multiphoton microscopy for the environmental monitoring of such pollutants have emerged in recent decades as effective tools for phytoremediation studies aimed at understanding the fate of these contaminants in plants...
January 19, 2017: Micron: the International Research and Review Journal for Microscopy
https://www.readbyqxmd.com/read/28177004/vibrationally-resolved-spectroscopic-studies-of-electronically-excited-states-of-1-8-naphthalic-anhydride-and-1-8-naphthalimide-a-delicate-interplay-between-one-%C3%AF-%C3%AF-and-two-n%C3%AF-states
#8
Elena Maltseva, Saeed Amirjalayer, Wybren Jan Buma
The spectroscopic and dynamic properties of the lower electronically excited states of 1,8-naphthalic anhydride and 1,8-naphthalimide have been studied in supersonically cooled molecular beams using nanosecond Resonance Enhanced MultiPhoton Ionization (REMPI) spectroscopic techniques in combination with quantum chemical calculations. The excitation spectra of these compounds show near - and even below - the apparent 0-0 transition to a strongly allowed electronic state, previously assigned as the S1(2(1)A1(ππ*)) state, a plethora of vibronic transitions that cannot simply be rationalized in terms of the Franck-Condon vibronic activity of that particular state...
February 8, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28164461/flexible-polygon-mirror-based-laser-scanning-microscope-platform-for-multiphoton-in-vivo-imaging
#9
Y X Li, V Gautam, A Brüstle, I A Cockburn, V R Daria, C Gillespie, K Gaus, C Alt, W M Lee
Commercial microscopy systems make use of tandem scanning i.e. either slow or fast scanning. We constructed, for the first time, an advanced control system capable of delivering a dynamic line scanning speed ranging from 2.7 kHz to 27 kHz and achieve variable frame rates from 5 Hz to 50 Hz (512 × 512). The dynamic scanning ability is digitally controlled by a new customized open-source software named PScan1.0. This permits manipulation of scanning rates either to gain higher fluorescence signal at slow frame rate without increasing laser power or increase frame rates to capture high speed events...
February 6, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28156058/aging-and-caloric-restriction-impact-adipose-tissue-adiponectin-and-circulating-lipids
#10
Karl N Miller, Maggie S Burhans, Josef P Clark, Porsha R Howell, Michael A Polewski, Tyler M DeMuth, Kevin W Eliceiri, Mary J Lindstrom, James M Ntambi, Rozalyn M Anderson
Adipose tissue expansion has been associated with system-wide metabolic dysfunction and increased vulnerability to diabetes, cancer, and cardiovascular disease. A reduction in adiposity is a hallmark of caloric restriction (CR), an intervention that extends longevity and delays the onset of these same age-related conditions. Despite these parallels, the role of adipose tissue in coordinating the metabolism of aging is poorly defined. Here, we show that adipose tissue metabolism and secretory profiles change with age and are responsive to CR...
February 3, 2017: Aging Cell
https://www.readbyqxmd.com/read/28154422/coherent-control-of-quasi-degenerate-stationary-like-states-via-multiple-resonances
#11
Yunrong Luo, Kuo Hai, Mingliang Zou, Wenhua Hai
We use three bosons held in a depth-tilt combined-modulated double-well to study coherent control of quantum transitions between quasi-degenerate stationary-like states (QDSLSs) with the same quasienergy. Within the high-frequency approximation and for multiple-resonance conditions, we analytically obtain the different QDSLSs including the maximal bipartite entangled states, which enable us to manipulate the transitions between QDSLSs without the observable multiphoton absorption and to simulate a two-qubit system with the considered bosons...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28151005/allograft-heart-valves-current-aspects-and-future-applications
#12
Milan Lisy, Guenay Kalender, Katja Schenke-Layland, Kelvin G M Brockbank, Anna Biermann, Ulrich Alfred Stock
Human heart valve allografts continue to represent almost perfect substitutes for heart valves. They have optimal hemodynamic characteristics and are highly resistant to infections. The first clinical use of allograft heart valves was as homovitals being transplanted after antibiotic incubation without any preservation. Since 1968, relatively standardized frozen cryopreservation (SFC) has been employed, including storage in vapor-phase liquid nitrogen. Disadvantages, particularly in pediatric patients, are limited availability due to organ scarcity, inability to grow, degeneration, immune response, and long-term failure...
February 2, 2017: Biopreservation and Biobanking
https://www.readbyqxmd.com/read/28147527/photodissociation-of-acetone-from-266-to-312-nm-dynamics-of-ch3-ch3co-channels-on-the-s0-and-t1-states
#13
Kin Long Kelvin Lee, Klaas Nauta, Scott H Kable
The photodissociation dynamics of acetone (CH3)2CO, cooled in a molecular beam, have been explored over the wavelength range 266-312 nm. Nascent CH3 fragments were detected by resonance-enhanced multiphoton ionization, followed by mass-selected ion imaging. For photolysis at λ = 306 nm, the image shows a sharp ring, which, when converted to a translational energy distribution, reveals a narrow Gaussian peak with a maximum at 90% of the available energy. As the photolysis energy is increased, the distribution slowly broadens and shifts to higher recoil translational energy...
January 28, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28146505/high-efficiency-supercontinuum-generation-in-solid-thin-plates-at-0-1%C3%A2-%C3%A2-tw-level
#14
Peng He, Yangyang Liu, Kun Zhao, Hao Teng, Xinkui He, Pei Huang, Hangdong Huang, Shiyang Zhong, Yujiao Jiang, Shaobo Fang, Xun Hou, Zhiyi Wei
Supercontinuum generation in a solid-state medium was investigated experimentally. A continuum covering 460 to 950 nm was obtained when 0.8 mJ/30 fs Ti:sapphire laser pulses were applied to seven thin fused silica plates at a 1 kHz repetition rate. The primary processes responsible for spectral broadening were self-phase modulation (SPM) and self-steepening, while SPM and self-focusing were balanced to optimize the spectral broadening and suppress the multiphoton process. The output was compressed to a 5.4 fs and a 0...
February 1, 2017: Optics Letters
https://www.readbyqxmd.com/read/28146237/measuring-deformation-in-the-mouse-optic-nerve-head-and-peripapillary-sclera
#15
Cathy Nguyen, Dan Midgett, Elizabeth C Kimball, Matthew R Steinhart, Thao D Nguyen, Mary E Pease, Ericka N Oglesby, Joan L Jefferys, Harry A Quigley
Purpose: To develop an ex vivo explant system using multiphoton microscopy and digital volume correlation to measure the full-field deformation response to intraocular pressure (IOP) change in the peripapillary sclera (PPS) and in the optic nerve head (ONH) astrocytic structure. Methods: Green fluorescent protein (GFP)-glutamate transporter-GLT1 (GLT1/GFP) mouse eyes were explanted and imaged with a laser-scanning microscope under controlled inflation. Images were analyzed for regional strains and changes in astrocytic lamina and PPS shape...
February 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28134333/discorrelated-quantum-states
#16
Evan Meyer-Scott, Johannes Tiedau, Georg Harder, Lynden K Shalm, Tim J Bartley
The statistical properties of photons are fundamental to investigating quantum mechanical phenomena using light. In multiphoton, two-mode systems, correlations may exist between outcomes of measurements made on each mode which exhibit useful properties. Correlation in this sense can be thought of as increasing the probability of a particular outcome of a measurement on one subsystem given a measurement on a correlated subsystem. Here, we show a statistical property we call "discorrelation", in which the probability of a particular outcome of one subsystem is reduced to zero, given a measurement on a discorrelated subsystem...
January 30, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28133923/a-comparative-study-of-ex-vivo-skin-optical-clearing-using-two-photon-microscopy
#17
Anton Sdobnov, Maxim E Darvin, Juergen Lademann, Valery Tuchin
Multiphoton tomography (MPT) is a prospective tool for imaging the skin structure. Aiming to increase the probing depth, a comparative ex vivo study of optical clearing of porcine ear skin was performed by using two optical clearing agents (OCAs), i.e., glycerol and iohexol (Omnipaque(TM) ) at different concentrations, which exhibit different osmotic properties. The results show that a topical application of glycerol or Omnipaque(TM) solutions onto the skin for 60 min significantly improved the depth and contrast of the MPT signals...
January 30, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/28127600/collision-energy-dependence-of-state-to-state-differential-cross-sections-for-rotationally-inelastic-scattering-of-h2o-by-he
#18
Gautam Sarma, Ashim Kumar Saha, Chandan Kumar Bishwakarma, Roy Scheidsbach, Chung-Hsin Yang, David Parker, Laurent Wiesenfeld, Udo Buck, Lazaros Mavridis, Sarantos Marinakis
The inelastic scattering of H2O by He as a function of collision energy in the range 381 cm(-1) to 763 cm(-1) at an energy interval of approximately 100 cm(-1) has been investigated in a crossed beam experiment using velocity map imaging. Change in collision energy was achieved by varying the collision angle between the H2O and He beam. We measured the state-to-state differential cross section (DCS) of scattered H2O products for the final rotational states JKaKc = 110, 111, 221 and 414. Rotational excitation of H2O is probed by (2 + 1) resonance enhanced multiphoton ionization (REMPI) spectroscopy...
January 27, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28122218/molecular-scale-biophysical-modulation-of-an-endothelial-membrane-by-oxidized-phospholipids
#19
Manuela A A Ayee, Elizabeth LeMaster, Tzu Pin Shentu, Dev K Singh, Nicolas Barbera, Dheeraj Soni, Chinnaswamy Tiruppathi, Papasani V Subbaiah, Evgeny Berdyshev, Irina Bronova, Michael Cho, Belinda S Akpa, Irena Levitan
The influence of two bioactive oxidized phospholipids on model bilayer properties, membrane packing, and endothelial cell biomechanics was investigated computationally and experimentally. The truncated tail phospholipids, 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) and 1-palmitoyl-2-glutaroyl-sn-glycero-3-phosphocholine (PGPC), are two major oxidation products of the unsaturated phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-phosphocholine. A combination of coarse-grained molecular dynamics simulations, Laurdan multiphoton imaging, and atomic force microscopy microindentation experiments was used to determine the impact of POVPC and PGPC on the structure of a multicomponent phospholipid bilayer and to assess the consequences of their incorporation on membrane packing and endothelial cell stiffness...
January 24, 2017: Biophysical Journal
https://www.readbyqxmd.com/read/28117567/sers-active-nanobiosensor-functionalized-by-self-assembled-3d-nickel-nanonetworks-for-glutathione-detection
#20
Sivaprasad Chinnakkannu Vijayakumar, Krishnan Venkatakrishnan, Bo Tan
We introduce a "non-noble metal" based SERS active nanobiosensor using a self-assembled 3D hybrid nickel nanonetwork. A tunable biomolecule detector fabricated by a bottom-up approach was functionalized using a multiphoton ionization energy mechanism to create a self-assembled 3D hybrid nickel nanonetwork. The nanonetwork was tested for SERS detection of crystal violet (CV) and glutathione (GSH) at two excitation wavelengths, 532 and 785 nm. The results reveal indiscernible peaks with a limit of detection (LOD) of 1 picomolar (pM) concentration...
February 3, 2017: ACS Applied Materials & Interfaces
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