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https://www.readbyqxmd.com/read/28102203/storing-single-photons-emitted-by-a-quantum-memory-on-a-highly-excited-rydberg-state
#1
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/28101541/inner-salt-shaped-small-molecular-photosensitizer-with-extremely-enhanced-two-photon-absorption-for-mitochondrial-targeted-photodynamic-therapy
#2
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
#3
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
#4
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/28098308/a-core-multiple-shell-nanostructure-enabling-concurrent-upconversion-and-quantum-cutting-for-photon-management
#5
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
#6
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
#7
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/28094455/body-regions-have-an-impact-on-the-collagen-elastin-index-of-the-skin-measured-by-non-invasive-in-vivo-vertical-two-photon-microscopy
#8
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
https://www.readbyqxmd.com/read/28094402/mesoporous-carbon-nanoshells-for-high-hydrophobic-drug-loading-multimodal-optical-imaging-controlled-drug-release-and-synergistic-therapy
#9
Hui Wang, Kui Wang, Qingxin Mu, Zachary R Stephen, Yanyan Yu, Shuiqin Zhou, Miqin Zhang
Loading and controlled release of sufficient hydrophobic drugs to tumor cells has been the bottleneck in chemotherapy for decades. Herein we report the development of a fluorescent and mesoporous carbon nanoshell (FMP-CNS) that exhibits a loading capacity for the hydrophobic drug paclitaxel (PTX) as high as ∼80 wt% and releases the drug in a controllable fashion under NIR irradiation (825 nm) at an intensity of 1.5 W cm(-2). The high drug loading is primarily attributed to its mesoporous structure and to the supramolecular π-stacking between FMP-CNSs and PTX molecules...
January 17, 2017: Nanoscale
https://www.readbyqxmd.com/read/28093553/enhancement-of-visual-cortex-plasticity-by-dark-exposure
#10
Irina Erchova, Asta Vasalauskaite, Valentina Longo, Frank Sengpiel
Dark rearing is known to delay the time course of the critical period for ocular dominance plasticity in the visual cortex. Recent evidence suggests that a period of dark exposure (DE) may enhance or reinstate plasticity even after closure of the critical period, mediated through modification of the excitatory-inhibitory balance and/or removal of structural brakes on plasticity. Here, we investigated the effects of a week of DE on the recovery from a month of monocular deprivation (MD) in the primary visual cortex (V1) of juvenile mice...
March 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
https://www.readbyqxmd.com/read/28092628/ultrafast-adiabatic-second-harmonic-generation
#11
Asaf Dahan, Assaf Levanon, Mordechai Katz, Haim Suchowski
We introduce a generalization of the adiabatic frequency conversion method for an efficient conversion of ultrashort pulses in the full nonlinear regime. Our analysis takes into account dispersion as well as two-photon processes and Kerr effect, allowing complete analysis of any three waves with arbitrary phase mismatched design and any nonlinear optical process. We use this analysis to design an efficient and robust second harmonic generation, the most widely used nonlinear process for both fundamental and applied research...
January 16, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28088631/an-esipt-based-two-photon-fluorescent-probe-detection-of-hydrogen-peroxide-in-live-cells-and-tissues
#12
Liyi Zhou, Yongbo Peng, Qianqian Wang, Qinlu Lin
A variety of diseases associated with human aging, which have a strong oxidative stress, but connecting age-related diseases and oxidative stress of the basic molecular mechanisms still insufficiently understood. Oxidative stress origins from the unregulated production of reactive oxygen species (ROS), and oxidative damaging to tissues and organs from subsequent oxidation-reduction chemistry by cellular mismanagement. In particular, H2O2 is a major by-product of ROS in live organisms and a common marker for oxidative stress, and its dynamic equilibrium can have various physiological and pathological consequences...
January 9, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/28088152/theoretical-description-of-circular-dichroism-in-photoelectron-angular-distributions-of-randomly-oriented-chiral-molecules-after-multi-photon-photoionization
#13
R E Goetz, T A Isaev, B Nikoobakht, R Berger, C P Koch
Photoelectron circular dichroism refers to the forward/backward asymmetry in the photoelectron angular distribution with respect to the propagation axis of circularly polarized light. It has recently been demonstrated in femtosecond multi-photon photoionization experiments with randomly oriented camphor and fenchone molecules [C. Lux et al., Angew. Chem., Int. Ed. 51, 4755 (2012) and C. S. Lehmann et al., J. Chem. Phys. 139, 234307 (2013)]. A theoretical framework describing this process as (2+1) resonantly enhanced multi-photon ionization is constructed, which consists of two-photon photoselection from randomly oriented molecules and successive one-photon ionization of the photoselected molecules...
January 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28081101/design-of-many-body-spin-states-of-rydberg-atoms-excited-to-highly-tunable-magnetic-sublevels
#14
Svetlana A Malinovskaya
Quantum control methodology is presented to design many-body spin states in a spin chain of Rydberg atoms using laser pulses and a magnetic field. A two-photon ladder-type configuration is implemented, which is advantageous due to the combined action of the one-photon and two-photon detunings as control parameters. Many-body spin states are designed consisting of an ensemble of spins encoded in sublevels of Rydberg states and coupled via the van der Waals interactions.
January 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28077982/surface-enhanced-hyper-raman-spectra-of-adenine-guanine-cytosine-thymine-and-uracil
#15
Fani Madzharova, Zsuzsanna Heiner, Marina Gühlke, Janina Kneipp
Using picosecond excitation at 1064 nm, surface-enhanced hyper-Raman scattering (SEHRS) spectra of the nucleobases adenine, guanine, cytosine, thymine, and uracil with two different types of silver nanoparticles were obtained. Comparing the SEHRS spectra with SERS data from the identical samples excited at 532 nm and with known infrared spectra, the major bands in the spectra are assigned. Due to the different selection rules for the one- and two-photon excited Raman scattering, we observe strong variation in relative signal strengths of many molecular vibrations obtained in SEHRS and SERS spectra...
July 21, 2016: Journal of Physical Chemistry. C, Nanomaterials and Interfaces
https://www.readbyqxmd.com/read/28077713/reversible-disruption-of-neuronal-mitochondria-by-ischemic-and-traumatic-injury-revealed-by-quantitative-two-photon-imaging-in-the-neocortex-of-anesthetized-mice
#16
Mikhail Kislin, Jeremy Sword, Ioulia V Fomitcheva, Deborah Croom, Evgeny Pryazhnikov, Eero Lihavainen, Dmytro Toptunov, Heikki Rauvala, Andre S Ribeiro, Leonard Khiroug, Sergei A Kirov
: Mitochondria play a variety of functional roles in cortical neurons, from metabolic support and neuroprotection to the release of cytokines that trigger apoptosis. In dendrites, mitochondrial structure is closely linked to their function, and fragmentation (fission) of the normally elongated mitochondria indicates loss of their function under pathological conditions, such as stroke and brain trauma. Using in vivo two-photon microscopy in mouse brain, we quantified mitochondrial fragmentation in a full spectrum of cortical injuries, ranging from severe to mild...
January 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28076762/a-leptin-analog-locally-produced-in-the-brain-acts-via-a-conserved-neural-circuit-to-modulate-obesity-linked-behaviors-in-drosophila
#17
Jennifer Beshel, Josh Dubnau, Yi Zhong
Leptin, a typically adipose-derived "satiety hormone," has a well-established role in weight regulation. Here we describe a functionally conserved model of genetically induced obesity in Drosophila by manipulating the fly leptin analog unpaired 1 (upd1). Unexpectedly, cell-type-specific knockdown reveals upd1 in the brain, not the adipose tissue, mediates obesity-related traits. Disrupting brain-derived upd1 in flies leads to all the hallmarks of mammalian obesity: increased attraction to food cues, increased food intake, and increased weight...
January 10, 2017: Cell Metabolism
https://www.readbyqxmd.com/read/28074876/scale-up-of-nature-s-tissue-weaving-algorithms-to-engineer-advanced-functional-materials
#18
Joanna L Ng, Lillian E Knothe, Renee M Whan, Ulf Knothe, Melissa L Knothe Tate
We are literally the stuff from which our tissue fabrics and their fibers are woven and spun. The arrangement of collagen, elastin and other structural proteins in space and time embodies our tissues and organs with amazing resilience and multifunctional smart properties. For example, the periosteum, a soft tissue sleeve that envelops all nonarticular bony surfaces of the body, comprises an inherently "smart" material that gives hard bones added strength under high impact loads. Yet a paucity of scalable bottom-up approaches stymies the harnessing of smart tissues' biological, mechanical and organizational detail to create advanced functional materials...
January 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28071906/single-conformation-spectroscopy-of-suberoylanilide-hydroxamic-acid-saha-a-molecule-bites-its-tail
#19
Di Zhang, Karl N Blodgett, Xiao Zhu, Timothy S Zwier
Suberoylanilide hydroxamic acid (C6H5NHCO(CH2)6CONHOH, SAHA) is a histone deacetylase inhibitor that causes growth arrest and differentiation of many tumor types and is an approved drug for the treatment of cancer. With a hydrogen-bonding amide group adjacent to its phenyl ring "head", and a hydroxamic acid group at the "tail" end of a C6 alkyl chain linker, SAHA possesses an interesting potential energy landscape to be probed by single-conformation methods. The alkyl chain's preference for extended structures is in competition with tail-to-head (T-H) or head-to-tail (H-T) hydrogen bonds between the amide and hydroxamic acid groups...
January 10, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28071723/hcn1-channels-reduce-the-rate-of-exocytosis-from-a-subset-of-cortical-synaptic-terminals
#20
Zhuo Huang, Gengyu Li, Carolina Aguado, Rafael Lujan, Mala M Shah
The hyperpolarization-activated cyclic nucleotide-gated (HCN1) channels are predominantly located in pyramidal cell dendrites within the cortex. Recent evidence suggests these channels also exist pre-synaptically in a subset of synaptic terminals within the mature entorhinal cortex (EC). Inhibition of pre-synaptic HCN channels enhances miniature excitatory post-synaptic currents (mEPSCs) onto EC layer III pyramidal neurons, suggesting that these channels decrease the release of the neurotransmitter, glutamate...
January 10, 2017: Scientific Reports
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