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https://www.readbyqxmd.com/read/28107381/in-vivo-two-photon-imaging-of-astrocytes-in-gfap-gfp-transgenic-mice
#1
Dongjun Guo, Jia Zou, Nicholas Rensing, Michael Wong
Astrocytes play important roles in normal brain function and neurological diseases. In vivo two-photon excitation laser scanning microscopy has the potential to reveal rapid, dynamic structural changes in cells in a variety of physiological and pathological conditions. The type of in vivo imaging method has been shown to affect the plasticity of dendritic spines of neurons, but the optimal in vivo imaging methods of astrocytes have not been established. We compared open-skull and thinned-skull imaging methods for two-photon laser microscopy of live astrocytes in neocortex of GFAP-GFP transgenic mice...
2017: PloS One
https://www.readbyqxmd.com/read/28106452/refractive-index-seen-by-a-probe-beam-interacting-with-a-laser-plasma-system
#2
D Turnbull, C Goyon, G E Kemp, B B Pollock, D Mariscal, L Divol, J S Ross, S Patankar, J D Moody, P Michel
We report the first complete set of measurements of a laser-plasma optical system's refractive index, as seen by a second probe laser beam, as a function of the relative wavelength shift between the two laser beams. Both the imaginary and real refractive index components are found to be in good agreement with linear theory using plasma parameters measured by optical Thomson scattering and interferometry; the former is in contrast to previous work and has implications for crossed-beam energy transfer in indirect-drive inertial confinement fusion, and the latter is measured for the first time...
January 6, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28106175/a-bioorthogonal-turn-on-fluorescent-probe-for-tracking-mitochondrial-nitroxyl-formation
#3
Kyoung Sunwoo, Kondapa Naidu Bobba, Ja-Yun Lim, Taegun Park, Arup Podder, June Seok Heo, Seung Gwan Lee, Sankarprasad Bhuniya, Jong Seung Kim
A bioreductant-resistant 'turn-on' chemodosimetric fluorescent probe Mito-1 has been developed for the detection of mitochondrial HNO in live cells. Mito-1 enables the detection of HNO as low as ∼18 nM. It has the capability to detect both exogenous and endogenous mitochondrial HNO formations in cellular milieus by providing fluorescence images. Its two-photon imaging ability fosters its use as a noninvasive imaging tool for the detection of mitochondrial nitroxyl.
January 20, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28106164/diverse-strategies-of-o2-usage-for-preventing-photo-oxidative-damage-under-co2-limitation-during-algal-photosynthesis
#4
Ginga Shimakawa, Yusuke Matsuda, Kensuke Nakajima, Masahiro Tamoi, Shigeru Shigeoka, Chikahiro Miyake
Photosynthesis produces chemical energy from photon energy in the photosynthetic electron transport and assimilates CO2 using the chemical energy. Thus, CO2 limitation causes an accumulation of excess energy, resulting in reactive oxygen species (ROS) which can cause oxidative damage to cells. O2 can be used as an alternative energy sink when oxygenic phototrophs are exposed to high light. Here, we examined the responses to CO2 limitation and O2 dependency of two secondary algae, Euglena gracilis and Phaeodactylum tricornutum...
January 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28102203/storing-single-photons-emitted-by-a-quantum-memory-on-a-highly-excited-rydberg-state
#5
Emanuele Distante, Pau Farrera, Auxiliadora Padrón-Brito, David Paredes-Barato, Georg Heinze, Hugues de Riedmatten
Strong interaction between two single photons is a long standing and important goal in quantum photonics. This would enable a new regime of nonlinear optics and unlock several applications in quantum information science, including photonic quantum gates and deterministic Bell-state measurements. In the context of quantum networks, it would be important to achieve interactions between single photons from independent photon pairs storable in quantum memories. So far, most experiments showing nonlinearities at the single-photon level have used weak classical input light...
January 19, 2017: Nature Communications
https://www.readbyqxmd.com/read/28102031/dual-nano-sized-contrast-agents-in-pet-mri-a-systematic-review
#6
REVIEW
Afsaneh Lahooti, Saeed Sarkar, Sophie Laurent, Saeed Shanehsazzadeh
Nowadays molecular imaging plays a vital role in achieving a successful targeted and personalized treatment. Hence, the approach of combining two or more medical imaging modalities was developed. The objective of this review is to systematically compare recent dual contrast agents in Positron Emission Tomography (PET)/Magnetic Resonance Imaging (MRI) and in some cases Single photon emission computed tomography (SPECT)/MRI in terms of some their characteristics, such as tumor uptake, and reticuloendothelial system uptake (especially liver) and their relaxivity rates for early detection of primary cancer tumor...
November 2016: Contrast Media & Molecular Imaging
https://www.readbyqxmd.com/read/28101541/inner-salt-shaped-small-molecular-photosensitizer-with-extremely-enhanced-two-photon-absorption-for-mitochondrial-targeted-photodynamic-therapy
#7
Wenbo Hu, Tingchao He, Rongcui Jiang, Jun Yin, Lin Li, Xiaomei Lu, Hui Zhao, Lei Zhang, Ling Huang, Handong Sun, Wei Huang, Quli Fan
Herein, we experimentally and theoretically demonstrate an unprecedentedly enhanced two-photon absorption in a small organic molecule by a simple introduction of an inner salt-shaped structure. Moreover, such an inner salt-shaped small molecule also exhibits superior singlet oxygen quantum yield and fascinating structure-inherent mitochondrial-targeting ability for highly efficient two-photon photodynamic therapy via a mitochondrial apoptosis pathway.
January 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28101527/regulation-of-physical-microglia-neuron-interactions-by-fractalkine-signaling-after-status-epilepticus
#8
Ukpong B Eyo, Jiyun Peng, Madhuvika Murugan, Mingshu Mo, Almin Lalani, Ping Xie, Pingyi Xu, David J Margolis, Long-Jun Wu
Microglia, the resident immune cells of the brain, perform elaborate surveillance in which they physically interact with neuronal elements. A novel form of microglia-neuron interaction named microglial process convergence (MPC) toward neuronal axons and dendrites has recently been described. However, the molecular regulators and pathological relevance of MPC have not been explored. Here, using high-resolution two-photon imaging in vivo and ex vivo, we observed a dramatic increase in MPCs after kainic acid- or pilocarpine-induced experimental seizures that was reconstituted after glutamate treatment in slices from mice...
November 2016: ENeuro
https://www.readbyqxmd.com/read/28101420/compact-diode-laser-source-for-multiphoton-biological-imaging
#9
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/28100670/two-new-single-exposure-multi-detector-neutron-spectrometers-for-radiation-protection-applications-in-workplace-monitoring
#10
J M Gómez-Ros, R Bedogni, D Bortot, C Domingo, A Esposito, M V Introini, M Lorenzoli, G Mazzitelli, M Moraleda, A Pola, D Sacco
This communication describes two new instruments, based on multiple active thermal neutron detectors arranged within a single moderator, that permit to unfold the neutron spectrum (from thermal to hundreds of MeV) and to determine the corresponding integral quantities with only one exposure. This makes them especially advantageous for neutron field characterisation and workplace monitoring in neutron-producing facilities. One of the devices has spherical geometry and nearly isotropic response, the other one has cylindrical symmetry and it is only sensitive to neutrons incident along the cylinder axis...
January 17, 2017: Radiation Protection Dosimetry
https://www.readbyqxmd.com/read/28099158/single-transmission-line-readout-method-for-silicon-photomultiplier-based-time-of-flight-and-depth-of-interaction-pet
#11
Guen Bae Ko, Jae Sung Lee
We propose a novel single transmission-line readout method for whole-body time-of-flight positron emission tomography applications, without compromising on performance. The basic idea of the proposed multiplexing method is the addition of a specially prepared tag signal ahead of the scintillation pulse. The tag signal is a square pulse that encodes photon arrival time and channel information. The two-dimensional position of a silicon photomultiplier (SiPM) array is encoded by the specific width and height of the tag signal...
January 18, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28099030/ultrafast-broadband-photodetectors-based-on-three-dimensional-dirac-semimetal-cd3as2
#12
Qinsheng Wang, Cai-Zhen Li, Shaofeng Ge, Jin-Guang Li, Wei Lu, Jiawei Lai, Xuefeng Liu, Junchao Ma, Dapeng Yu, Zhi-Min Liao, Dong Sun
Photodetection with extreme performances in terms of ultrafast response time, broad detection wavelength range, and high sensitivity has wide range of optoelectronic and photonic applications, such as optical communications, interconnects, imaging and remote sensing. Graphene, a typical two-dimensional Dirac semimetal, has shown excellent potential toward high performance photodetector with high operation speed, broadband response and efficient carrier multiplications benefiting from its linear dispersion band structure with high carrier mobility and zero bandgap...
January 18, 2017: Nano Letters
https://www.readbyqxmd.com/read/28098986/investigation-of-the-energy-transfer-mechanism-in-ho-3-and-yb-3-codoped-lu2o3-phosphor-with-efficient-near-infrared-downconversion
#13
Guotao Xiang, Yan Ma, Xianju Zhou, Sha Jiang, Li Li, Xiaobing Luo, Zhendong Hao, Xia Zhang, Guo-Hui Pan, Yongshi Luo, Jiahua Zhang
A high-temperature solid-state method was used to synthesize the Ho(3+)- and Yb(3+)-codoped cubic Lu2O3 powders. The crystal structures of the as-prepared powders were characterized by X-ray diffraction. The energy-transfer (ET) phenomenon between Ho(3+) ions and Yb(3+) ions was verified by the steady-state spectra including visible and near-infrared (NIR) regions. Beyond that, the decay curves were also measured to certify the existence of the ET process. The downconversion phenomena appeared when the samples were excited by 446 nm wavelength corresponding to the transition of Ho(3+): (5)I8→(5)G6/(5)F1...
January 18, 2017: Inorganic Chemistry
https://www.readbyqxmd.com/read/28098308/a-core-multiple-shell-nanostructure-enabling-concurrent-upconversion-and-quantum-cutting-for-photon-management
#14
Wei Shao, Guanying Chen, Tymish Y Ohulchanskyy, Chunhui Yang, Hans Ågren, Paras N Prasad
Photon management enables the manipulation of the number of input photons by conversion of two or more light quanta into one (upconversion) or vice versa (quantum cutting). Simultaneous realization of both these processes in a single unit provides unique opportunities of efficient utilization of photons throughout a broad spectral range. Yet, concurrent realization of these two parallel optical processes in one single unit remains elusive, limiting its impact on many existing or possible future applications such as for panchromatic photovoltaics...
January 18, 2017: Nanoscale
https://www.readbyqxmd.com/read/28098223/dispersion-of-nonresonant-third-order-nonlinearities-in-silicon-carbide
#15
Francesco De Leonardis, Richard A Soref, Vittorio M N Passaro
In this paper we present a physical discussion of the indirect two-photon absorption (TPA) occuring in silicon carbide with either cubic or wurtzite structure. Phonon-electron interaction is analyzed by finding the phonon features involved in the process as depending upon the crystal symmetry. Consistent physical assumptions about the phonon-electron scattering mechanisms are proposed in order to give a mathematical formulation to predict the wavelength dispersion of TPA and the Kerr nonlinear refractive index n2...
January 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28097863/mitochondria-targeted-protein-ruthenium-photosensitizer-for-efficient-photodynamic-applications
#16
Sabyasachi Chakrabortty, Bikram Keshari Agrawalla, Anne Stumper, Naidu M Vegi, Stephan Fischer, Christian Reichardt, Michael Kögler, Benjamin Dietzek, Michaela Feuring-Buske, Christian Buske, Sven Rau, Tanja Weil
Organelle-targeted photosensitization represents a promising approach in photodynamic therapy where the design of the active photosensitizer (PS) is very crucial. In this work, we developed a macromolecular PS with multiple copies of mitochondria-targeting groups and ruthenium complexes that displays highest phototoxicity towards several cancerous cell lines. In particu-lar, enhanced anti-cancer activity was demonstrated in acute myeloid leukemia cell lines, where significant impairment of proliferation and clonogenicity occurs...
January 18, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28097172/transcript-levels-of-phytoene-desaturase-gene-in-dunaliella-salina-teod-as-affected-by-pbs-nanoparticles-and-light-intensity
#17
Hajar Zamani, Ali Moradshahi
Phytoene synthase (Psy) and Phytoene desaturase (Pds) are the first two regulatory enzymes in the carotenoids biosynthetic pathway. The genes Psy and Pds are under transcriptional control in many photosynthetic organisms. In the present study, using quantitative real time- PCR (qRT-PCR), the effects of uncoated and gum-Arabic coated PbS nanoparticles (GA-coated PbS NPs) and light intensity on the mRNA levels of Pds were investigated. Relative to mRNA level of Pds at 100 µmol photon m-2 s-1 light intensity (control culture), 2...
September 2016: Molecular Biology Research Communications
https://www.readbyqxmd.com/read/28096330/spectroscopic-evidence-for-bulk-band-inversion-and-three-dimensional-massive-dirac-fermions-in-zrte5
#18
Zhi-Guo Chen, R Y Chen, R D Zhong, John Schneeloch, C Zhang, Y Huang, Fanming Qu, Rui Yu, Q Li, G D Gu, N L Wang
Three-dimensional topological insulators (3D TIs) represent states of quantum matters in which surface states are protected by time-reversal symmetry and an inversion occurs between bulk conduction and valence bands. However, the bulk-band inversion, which is intimately tied to the topologically nontrivial nature of 3D Tis, has rarely been investigated by experiments. Besides, 3D massive Dirac fermions with nearly linear band dispersions were seldom observed in TIs. Recently, a van der Waals crystal, ZrTe5, was theoretically predicted to be a TI...
January 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28094849/the-collimator-monitoring-fill-factor-of-a-two-dimensional-detector-array-a-measure-of-its-ability-to-detect-collimation-errors
#19
Tenzin Sonam Stelljes, Hui Khee Looe, Dietrich Harder, Björn Poppe
PURPOSE: Two-dimensional detector arrays are routinely used for constancy checks and treatment plan verification in photon-beam radiotherapy. In addition to the spatial resolution of the dose profiles, the "coverage" of the radiation field with respect to the detection of any beam collimation deficiency appears as the second characteristic feature of a detector array. The here proposed "collimator monitoring fill factor" (CM fill factor) has been conceived to serve as a quantitative characteristic of this "coverage"...
January 17, 2017: Medical Physics
https://www.readbyqxmd.com/read/28094455/body-regions-have-an-impact-on-the-collagen-elastin-index-of-the-skin-measured-by-non-invasive-in-vivo-vertical-two-photon-microscopy
#20
Carolin Czekalla, Karl Heinz Schönborn, Nadine Döge, Sora Jung, Maxim E Darvin, Jürgen Lademann, Martina C Meinke
No abstract text is available yet for this article.
January 17, 2017: Experimental Dermatology
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