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Nicole S Stivers, Nicolas Pelisch, Ben C Orem, Joshua Williams, Jacqueline M Nally, David P Stirling
Microglia/macrophage activation and recruitment following spinal cord injury (SCI) is associated with both detrimental and reparative functions. Stimulation of the innate immune receptor Toll-like receptor-2 (TLR2) has shown to be beneficial following SCI, and it increases axonal regeneration following optic nerve crush. However, the mechanism(s) remain unclear. As microglia express high levels of TLR2, we hypothesized that modulating the microglial response to injury using a specific TLR2 agonist, Pam3CSK4, would prevent secondary-mediated white matter degeneration following SCI...
April 23, 2017: Experimental Neurology
Neda Haghayegh Jahromi, Heidi Tardent, Gaby Enzmann, Urban Deutsch, Naoto Kawakami, Stefan Bittner, Dietmar Vestweber, Frauke Zipp, Jens V Stein, Britta Engelhardt
T-cell migration across the blood-brain barrier (BBB) is a crucial step in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Two-photon intravital microscopy (2P-IVM) has been established as a powerful tool to study cell-cell interactions in inflammatory EAE lesions in living animals. In EAE, central nervous system inflammation is strongly pronounced in the spinal cord, an organ in which 2P-IVM imaging is technically very challenging and has been limited to the lumbar spinal cord...
2017: Frontiers in Immunology
Krisztián Kertész, Gábor Piszter, Zsolt Endre Horváth, Zsolt Bálint, László Péter Biró
While numerous papers have investigated the effects of thermal stress on the pigmentary colours of butterfly wings, such studies regarding structural colours are mostly lacking, despite the important role they play in sexual communication. To gain insight into the possible differences between the responses of the two kinds of colouration, we investigated the effects of prolonged cold stress (cooling at 5 °C for up to 62 days) on the pupae of Polyommatus icarus butterflies. The wing surfaces coloured by photonic crystal-type nanoarchitectures (dorsal) and by pigments (ventral) showed markedly different behaviours...
April 25, 2017: Scientific Reports
Zhi-Rong Zhong
We construct shortcuts to adiabatic passage to achieve controllable and fast quantum-information transfer (QIT) between arbitrary two distant nodes in a two-dimensional (2D) quantum network. Through suitable designing of time-dependent Rabi frequencies, we show that perfect QIT between arbitrary two distant nodes can be rapidly achieved. Numerical simulations demonstrate that the proposal is robust to the decoherence caused by atomic spontaneous emission and cavity photon leakage. Additionally, the proposed scheme is also insensitive to the variations of the experimental parameters...
December 5, 2016: Scientific Reports
Bogdan Dragnea
The assembly line is a commonly invoked example of allopoiesis, the process whereby a system produces a different system than itself. In this sense, virus production in plants is an instance of bio-enabled bottom-up allopoiesis because the plant host can be regarded as a programmable assembly line for the virus. Reprogramming this assembly line and integrating it into a larger lineup of chemical manipulations has seen a flurry of activity recently, with more sophisticated systems emerging every year. The field of virus nanomaterials now has several subdisciplines that focus on virus shells as assemblers, scaffolds for molecular circuitry, chemical reactors, magnetic and photonic beacons, and therapeutic carriers...
April 25, 2017: ACS Nano
Qiaoli Hao, Xulan Deng, Jinyou Long, Yanmei Wang, Bumaliya Abulimiti, Bing Zhang
Ultrafast electronic relaxation processes following two photoexcitation of 400nm in p-Fluorotoluene (pFT) have been investigated utilizing time-resolved photoelectron imaging coupled with time-resolved mass spectroscopy. Cascaded electronic relaxation processes started from the electronically excited S2 state are directly imaged in real time and well characterized by two distinct time constants of ~85±10fs and 2.4±0.3ps. The rapid component corresponds to the lifetime of the initially excited S2 state, including the structure relaxation from the Franck-Condon region to the conical intersection of S2/S1 and the subsequent internal conversion to the highly excited S1 state...
April 19, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Shan He, Yafu Guan, Dong Liu, Xusheng Xia, Baodong Gai, Shu Hu, Jingwei Guo, Fengting Sang, Yuqi Jin
In optically pumped laser systems, rare gas lasers (RGLs) are a field of great interest for researchers. Gas laser regimes with metastable Ne, Ar, and Kr atoms have been investigated, while studies of RGLs based on metastable Xe are sparse. In this work, when a strong excitation laser (2.92 mJ/pulse, 7.44*10^5 W/cm2) was applied to excite Xe atoms from the ground state to the 6p[1/2]0 state, an interesting phenomenon emerged: An intense fluorescence of 980 nm (6p[1/2]1-6s[3/2]2) was produced. However, when the energy of excitation laser was decreased to 0...
April 25, 2017: Journal of Physical Chemistry. A
Yoichi Kobayashi, Hajime Okajima, Hikaru Sotome, Takeshi Yanai, Katsuya Mutoh, Yusuke Yoneda, Yasuteru Shigeta, Akira Sakamoto, Hiroshi Miyasaka, Jiro Abe
Delocalized biradicals have been extensively studied because of fundamental interests to singlet biradicals and several potential applications such as to two-photon absorption materials. However, many of the biradical studies only focus on the static properties of the rigid molecular structures. It is expected that the biradical properties of the delocalized biradicals are sensitive to the subtle changes of the molecular structures and their local environments. Therefore, the studies of the dynamic properties of the system will give further insight into stable radical chemistry...
April 25, 2017: Journal of the American Chemical Society
Hyo-Min Cho, Huanjun Ding, Nikita Kumar, David Sennung, Sabee Molloi
The aim of this study is to investigate the feasibility of water and lipid as calibration phantoms for accurate dual energy breast density quantification. Dual energy calibration was performed on a mammography system based on scanning multi-slit Si strip photon-counting detectors using plastic water and adipose-equivalent phantoms as the basis materials. Two different methods were used to convert the dual energy decomposition measurements in plastic phantom thicknesses into the true water and lipid basis materials...
April 25, 2017: Physics in Medicine and Biology
Orit Kaidar-Person, Timothy M Zagar, Jorge Daniel Oldan, Jason Matney, Ellen L Jones, Shiva Das, Brian C Jensen, Richard C Zellars, Terence Z Wong, Lawrence B Marks
PURPOSE: Cardiac single-photon emission computed tomography (SPECT) is often used to identify defects in myocardial perfusion due to atherosclerotic coronary artery disease. It was also used in studies to evaluate radiation therapy (RT)-associated cardiac abnormalities. In the current review, we aim to evaluate the rates of post-RT cardiac SPECT early perfusion abnormalities and relate this to the irradiated left ventricular volume. METHODS: The studies cited in this systematic review were identified using the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines...
April 21, 2017: Breast Cancer Research and Treatment
Waleed F Mourad, John K Ma, Satyaseelan Packianathan, Weisi Yan, Sherif G Shaaban, Edward M Marchan, Lamiaa E Abdallah, Rei He, Paul N Mobit, Chunli Claus Yang, Srinivasan Vijayakumar
AIM: A single-institution, retrospective study was performed to investigate potential techniques to minimize radiation exposure to the testicles during heterotopic ossification (HO) prophylaxis. We report the impact of split-beam technique (SBT) and different photon energies on the total dose of radiation received by the testicles during prophylaxis of HO. MATERIALS AND METHODS: Between 2008 and 2010, we identified 64 patients with traumatic acetabular fractures who underwent surgery followed by radiation therapy (RT) without testicular shielding...
May 2017: In Vivo
Alexey Bondar, Josef Lazar
The Gi/o protein family transduces signals from a diverse group of G protein-coupled receptors (GPCRs). The observed specificity of Gi/o-GPCR coupling and high rate of Gi/o signal transduction have been hypothesized to be enabled by existence of stable associates between Gi/o proteins and their cognate GPCRs in the inactive state (Gi/o-GPCR preassembly). To test this hypothesis, we applied the recently developed technique of two-photon polarization microscopy (2PPM) to Gαi1 subunits labeled with fluorescent proteins and four GPCRs (the α2A-adrenergic receptor (α2A-AR), γ-aminobutyric acid receptor B (GABAB), cannabinoid receptor type 1 (CB1R) and dopamine receptor type 2 (D2R))...
April 24, 2017: Journal of Biological Chemistry
Ping Gu, Jiawei Chen, Mingjie Wan, Zhuo Chen, Zhenlin Wang
We theoretically and experimentally investigate the multipolar hybrid plasmon-photon modes supported by a dielectric-metal core-shell resonator consisting of a dielectric core wrapped by a thin silver shell and the whispering-gallery modes in its pure dielectric counterpart (the dielectric sphere with the same size). We theoretically demonstrate that in a certain wavelength range the achievable maximum Q-factors of hybrid modes could be either larger or smaller than that of whispering-gallery modes, depending on the size of the resonator...
April 17, 2017: Optics Express
Tianyu Tu, Fufei Pang, Shan Zhu, Jiajing Cheng, Huanhuan Liu, Jianxiang Wen, Tingyun Wang
We have theoretically and experimentally demonstrated a novel approach to excite Bloch surface wave (BSW) on tapered optical fibers, which are coated with one-dimensional photonic crystal (1DPC) consisting of periodic TiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> by atomic layer deposition technology. Two resonant dips are found in transmission spectra that are originated from the excitation of BSW for p-polarized light and s-polarized light, respectively. For the first time, we have demonstrated the developed device for refractive index (RI) sensing...
April 17, 2017: Optics Express
Yuan-Yuan Zhao, Zhibo Hou, Guo-Yong Xiang, Yong-Jian Han, Chuan-Feng Li, Guang-Can Guo
Quantum state tomography is a key technology for fully determining a quantum state. Unfortunately, standard quantum state tomography is intractable for general many-body quantum states, because the number of measurements and the post-processing time increase exponentially with the size of the system. However, for the matrix product states (MPSs), there exists an efficient method using linearly scaled local measurements and polynomially scaled post-processing times. In this study, we demonstrate the validity of the method in practice by reconstructing a four-photon MPS from its local two- or three-photon reduced-density matrices with the presence of statistical errors and systematical errors in experiment...
April 17, 2017: Optics Express
Xiaomin Nie, Eva Ryckeboer, Gunther Roelkens, Roel Baets
We demonstrate a novel type of Fourier Transform Spectrometer (FTS) that can be realized with CMOS compatible fabrication techniques. This FTS contains no moving components and is based on the direct detection of the interferogram generated by the interference of the evanescent fields of two co-propagating waveguide modes. The theoretical analysis indicates that this type of FTS inherently has a large bandwidth (>100 nm). The first prototype that is integrated on a Si<sub>3</sub>N<sub>4</sub> waveguide platform is demonstrated and has an extremely small size (0...
April 17, 2017: Optics Express
Simone Ferrari, Vadim Kovalyuk, Wladislaw Hartmann, Andreas Vetter, Oliver Kahl, Changhyoup Lee, Alexander Korneev, Carsten Rockstuhl, Gregory Gol'tsman, Wolfram Pernice
We investigate how the bias current affects the hot-spot relaxation dynamics in niobium nitride. We use for this purpose a near-infrared pump-probe technique on a waveguide-integrated superconducting nanowire single-photon detector driven in the two-photon regime. We observe a strong increase in the picosecond relaxation time for higher bias currents. A minimum relaxation time of (22 ± 1) ps is obtained when applying a bias current of 50% of the switching current at 1.7 K bath temperature. We also propose a practical approach to accurately estimate the photon detection regimes based on the reconstruction of the measured detector tomography at different bias currents and for different illumination conditions...
April 17, 2017: Optics Express
Jie You, Nicolae C Panoiu
A computational approach to evaluate the bit-error ratio (BER) in silicon photonic systems employing high-order phase-shift keying (PSK) modulation formats is presented. Specifically, the investigated systems contain a silicon based optical interconnect, namely a strip silicon photonic waveguide or a silicon photonic crystal waveguide, and direct-detection receivers suitable to detect PSK and amplitude-shaped PSK signals. The superposition of a PSK signal and complex additive white Gaussian noise passes through the optical interconnect and subsequently through two detection-branch receivers...
April 17, 2017: Optics Express
Marit Ulset Nordsveen, Chi Kwong Tang, Jarle Gran
We demonstrate the use of a dual-mode detector for determining the internal quantum deficiency of a silicon photodiode without the use of an external reference. This is achieved by combining two different principles for measuring optical power in one device, where the photodiode is used as absorber for both thermal and photon detection. Thermal detection is obtained by the same principle as for an electrical substitution radiometer (ESR), with a type A measurement uncertainty of 0.34 % in unstabilized room temperature...
April 17, 2017: Optics Express
Takahide Sakaidani, Ryo Kobayashi, Naoto Namekata, Go Fujii, Daiji Fukuda, Shuichiro Inoue
High-order dispersion of long-range surface-plasmon-polariton waveguides (LR-SPP-WGs) have been investigated using a two-photon interferometer. Since linear and even-ordered dispersions in two-photon interferometry are cancelled out by a nonlocal quantum correlation, odd-ordered dispersions of millimeter-long LR-SPP-WGs are revealed. Even under the highly dispersive condition, the indistinguishability between two photons emerged from LR-SPP-WGs was well preserved. In addition, we demonstrated a strong polarization-selection by the LR-SPP-WGs that leads to the polarization-stable and high-fidelity quantum interference...
April 17, 2017: Optics Express
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