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Zhuolin Liu, Kazuhiro Kurokawa, Furu Zhang, John J Lee, Donald T Miller
Ganglion cells (GCs) are fundamental to retinal neural circuitry, processing photoreceptor signals for transmission to the brain via their axons. However, much remains unknown about their role in vision and their vulnerability to disease leading to blindness. A major bottleneck has been our inability to observe GCs and their degeneration in the living human eye. Despite two decades of development of optical technologies to image cells in the living human retina, GCs remain elusive due to their high optical translucency...
November 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
Yang Bai, Miao Li, Yanmei Zhou, Lei Ma, Qian Qiao, Wanling Hu, Wei Li, Zachary Patrick Wills, Wen-Biao Gan
BACKGROUND: Alzheimer's disease (AD) is characterized by amyloid deposition, tangle formation as well as synapse loss. Synaptic abnormalities occur early in the pathogenesis of AD. Identifying early synaptic abnormalities and their underlying mechanisms is likely important for the prevention and treatment of AD. METHODS: We performed in vivo two-photon calcium imaging to examine the activities of somas, dendrites and dendritic spines of layer 2/3 pyramidal neurons in the primary motor cortex in the APPswe/PS1dE9 mouse model of AD and age-matched wild type control mice...
November 14, 2017: Molecular Neurodegeneration
Ping Yue, Xiuli Yang, Peng Ning, Xinguo Xi, Haizhu Yu, Yan Feng, Rong Shao, Xiangming Meng
A novel mitochondria-targeted ratiometric two-photon fluorescent probe (Mito-MQ) for detecting intracellular cysteine (Cys) and homocysteine (Hcy) has been designed. Mito-MQ showed the ratiometric fluorescent detection signal (the green-to-blue emissionfrom 517nm to 460nm) to cysteine (Cys) and homocysteine (Hcy) over glutathione (GSH), along with the fast response rate (10min). The detection mechanism was illustrated by (1)H NMR, ESI-MS and theoretical calculation. The co-localization coefficient of 0.87 between Mito-MQ and MitoTracker Red revealed that the probe was predominantly present in mitochondria, therefore, Mito-MQ was successfully applied to detect mitochondrial oxidative stress by detecting the change of Cys/Hcy...
February 1, 2018: Talanta
Francesco Talotta, Jean-Louis Heully, Fabienne Alary, Isabelle M Dixon, Leticia Gonzalez, Martial Boggio-Pasqua
The N→O linkage photoisomerization mechanism in a ruthenium nitrosyl complex, [RuCl(NO)(py)4]2+, for which a quasi complete photoconversion between the stable nitrosyl (N-bonded) and metastable isonitrosyl (O-bonded) isomers has been observed under continuous irradiation of the crystal at 473 nm (Cormary et al., Acta Cryst. B 2009, 65, 612-623), is investigated using multiconfigurational second-order perturbation theory (CASPT2). The results support efficient intersystem crossing pathways from the initially excited singlet states to the lowest triplet excited state of metal-to-ligand charge transfer character (3MLCT)...
November 14, 2017: Journal of Chemical Theory and Computation
R Glenn Hepfer, Peng Chen, Kelvin G M Brockbank, Alyce L Jones, Amanda K Burnette, Zhen Chen, Elizabeth D Greene, Lia H Campbell, Hai Yao
The purpose of this study was to determine the impact of elevated temperature exposure in tissue banking on soft tissues. A secondary objective was to determine the relative ability of various assays to detect changes in soft tissues due to temperature deviations. Porcine pulmonary heart valve leaflets exposed to 37 °C were compared with those incubated at 52 and 67 °C for 10, 30 and 100 min. The analytical methods consisted of (1) viability assessment using the resazurin assay, (2) collagen content using the Sircol assay, and (3) permeability assessment using an electrical conductivity assay...
November 13, 2017: Cardiovascular Engineering and Technology
Shuxin Wei, Jie Liu, Yuanyuan Zhao, Tingbin Zhang, Mei-Ling Zheng, Feng Jin, Xianzi Dong, Jinfeng Xing, Xuanming Duan
The microtechnology of controlling stimuli-responsive biomaterials at micrometer scale is crucial for biomedical applications. Here, we report bovine serum albumin (BSA)-based three-dimensional (3D) microstructures with tunable surface morphology and pH-responsive properties via two-photon polymerization (TPP) microfabrication technology. The laser processing parameters including laser power, scanning speed and layer distance are optimized for the fabrication of well-defined 3D BSA microstructures. The tunable morphology of BSA microstructures and a wide range pH response corresponding to the swelling ratio from 1...
November 13, 2017: ACS Applied Materials & Interfaces
Axel Jacobi von Wangelin, Michael Neumeier, Raul Perez, Michal Majek, Diego Sampedro, Victor de la Pena O'Shea
Photocatalytic bond activations are generally limited by the photon energy and the efficiency of energy and electron transfer processes. Direct two-photon processes provide sufficient energy but the ultra-short lifetimes of the excited states prohibit chemical reactions. The commercial dye 9,10-dicyanoanthracene enabled photocatalytic aromatic substitutions of non-activated aryl halides. This reaction operates under VIS irradiation via sequential photonic, electronic, and photonic activation of the simple organic dye...
November 13, 2017: Chemistry: a European Journal
Tejapratap Bollu, Nathan R Cornelius, John Sunwoo, Nozomi Nishimura, Chris B Schaffer, Peter C Doerschuk
Computations are described which estimate flows in all branches of the cortical surface arteriole network from two-photon excited fluorescence (2PEF) microscopy images which provide the network topology and, in selected branches red blood cell (RBC) speeds and lumen diameters. Validation is done by comparing the flow predicted by the model with experimentally measured flows and by comparing the predicted flow redistribution in the network due to single-vessel strokes with experimental observations. The model predicts that tissue is protected from RBC flow decreases caused by multiple occlusions of surface arterioles but not penetrating arterioles...
January 1, 2017: Journal of Cerebral Blood Flow and Metabolism
Beatrix C Hiesmayr, Pawel Moskal
The electron-positron annihilation into two photons is a standard technology in medicine to observe e.g. metabolic processes in human bodies. A new tomograph will provide the possibility to observe not only direct e (+) e (-) annihilations but also the 3 photons from the decay of ortho-positronium atoms formed in the body. We show in this contribution that the three-photon state with respect to polarisation degrees of freedom depends on the angles between the photons and exhibits various specific entanglement features...
November 10, 2017: Scientific Reports
Yu-Jia Fu, Hui-Wen Yao, Xiao-Yan Zhu, Xiao-Feng Guo, Hong Wang
Hydrogen sulfide (H2S) is a new endogenously generated gasotransmitter and has implicated in many physiologies and pathologies closely related to its intracellular and intercellular signaling transduction. Although many fluorescent probes have been exploited to track and quantify H2S in living systems, none of them could be used for monitoring intercellular transmission of H2S. Herein, we developed a cell surface specific H2S probe, 4-azido-6-sulfo-N-hexadecyl-1,8-naphthalimide, sodium salt (ASNHN-N3), trying to investigate the behaviors of extracellular release of H2S...
November 22, 2017: Analytica Chimica Acta
Sjoerd A Veldhuis, Yong Kang Eugene Tay, Annalisa Bruno, Sai S H Dintakurti, Saikat Bhaumik, Subas Kumar Muduli, Mingjie Li, Nripan Mathews, Tze Chien Sum, Subodh G Mhaisalkar
We report the high yield synthesis of about 11 nm sized CH3NH3PbBr3 nanocrystals with near-unity photoluminescence quantum yield. The nanocrystals are formed in the presence of surface-binding ligands through their direct precipitation in a benzyl alcohol/toluene phase. The benzyl alcohol plays a pivotal role in steering the surface ligands binding motifs on the NC surface, resulting in enhanced surface-trap passivation and near-unity PLQY values. We further demonstrate that thin films from purified CH3NH3PbBr3 nanocrystals are stable >4 months in air, exhibit high optical gain (about 520 cm(-1)), and display stable, ultralow amplified spontaneous emission thresholds of 13...
November 14, 2017: Nano Letters
Jiangheng Guan, Jingcheng Li, Shanshan Liang, Ruijie Li, Xingyi Li, Xiaozhe Shi, Ciyu Huang, Jianxiong Zhang, Junxia Pan, Hongbo Jia, Le Zhang, Xiaowei Chen, Xiang Liao
Two-photon Ca(2+) imaging has become a popular approach for monitoring neuronal population activity with cellular or subcellular resolution in vivo. This approach allows for the recording of hundreds to thousands of neurons per animal and thus leads to a large amount of data to be processed. In particular, manually drawing regions of interest is the most time-consuming aspect of data analysis. However, the development of automated image analysis pipelines, which will be essential for dealing with the likely future deluge of imaging data, remains a major challenge...
November 9, 2017: Brain Structure & Function
Berquin D Feese, Diego E Pafundo, Meredith N Schmehl, Sandra J Kuhlman
Activity of cortical inhibitory interneurons is rapidly reduced in response to monocular deprivation during the critical period for ocular dominance plasticity and in response to salient events encountered during learning. In the case of primary sensory cortex, a decrease in mean evoked firing rate of parvalbumin-positive (PV) inhibitory neurons is causally linked to a reorganization of excitatory networks following sensory perturbation. Converging evidence indicates that it is deprivation, and not an imbalance between open and closed eye inputs, that triggers rapid plasticity in PV neurons...
November 8, 2017: Journal of Neurophysiology
Petr Tvrdik, M Yashar S Kalani
Microglia, the innate immune sentinels of the central nervous system, are the most dynamic cells in the brain parenchyma. They are the first responders to insult and mediate neuroinflammation. Following cellular damage, microglia extend their processes towards the lesion, modify their morphology, release cytokines and other mediators, and eventually migrate towards the damaged area and remove cellular debris by phagocytosis. Intracellular Ca(2+) signaling plays important roles in many of these functions. However, Ca(2+) in microglia has not been systematically studied in vivo...
November 8, 2017: International Journal of Molecular Sciences
A Yu Dmitriev, R Shaikhaidarov, V N Antonov, T Hönigl-Decrinis, O V Astafiev
Superconducting quantum systems (artificial atoms) have been recently successfully used to demonstrate on-chip effects of quantum optics with single atoms in the microwave range. In particular, a well-known effect of four wave mixing could reveal a series of features beyond classical physics, when a non-linear medium is scaled down to a single quantum scatterer. Here we demonstrate the phenomenon of quantum wave mixing (QWM) on a single superconducting artificial atom. In the QWM, the spectrum of elastically scattered radiation is a direct map of the interacting superposed and coherent photonic states...
November 7, 2017: Nature Communications
F Bolze, S Jenni, A Sour, V Heitz
Two-photon excitation has attracted the attention of biologists, especially after the development of two-photon excited microscopy in the nineties. Since then, new applications have rapidly emerged such as the release of biologically active molecules and photodynamic therapy (PDT) using two-photon excitation. PDT, which requires a light-activated drug (photosensitiser), is a clinically approved and minimally invasive treatment for cancer and for non-malignant diseases. This feature article focuses on the engineering of molecular two-photon photosensitisers for PDT, which should bring important benefits to the treatment, increase the treatment penetration depth with near-infrared light excitation, improve the spatial selectivity and reduce the photodamage to healthy tissues...
November 8, 2017: Chemical Communications: Chem Comm
Miki Sato, Yuki Maeda, Toshio Ishioka, Akira Harata
The detection limits and photoionization thresholds of polycyclic aromatic hydrocarbons and their chlorides and nitrides on the water surface are examined using laser two-photon ionization and single-photon ionization, respectively. The laser two-photon ionization methods are highly surface-selective, with a high sensitivity for aromatic hydrocarbons tending to accumulate on the water surface in the natural environment due to their highly hydrophobic nature. The dependence of the detection limits of target aromatic molecules on their physicochemical properties (photoionization thresholds relating to excess energy, molar absorptivity, and the octanol-water partition coefficient) is discussed...
November 8, 2017: Analyst
Minsoo Cho, Seulgi Han, Hyemin Kim, Ki Su Kim, Sei Kwang Hahn
Human parathyroid hormone 1-34 fragment (PTH1-34) has been used as a FDA-approved therapeutics to treat osteoporosis by daily subcutaneous injection. In this work, we successfully developed PTH1-34 conjugated hyaluronic acid (HA) for the transdermal treatment of osteoporosis with improved patient compliance. HA-PTH1-34 conjugate was synthesized by the coupling reaction between aldehyde group introduced to HA and amine group of PTH1-34. After characterization by gel permeation chromatography (GPC) and ELISA, the biological effect of HA-PTH1-34 conjugate on the proliferation of human osteoblast cells was confirmed by in vitro calcium colorimetric assay and cAMP assay...
November 8, 2017: Journal of Biomaterials Science. Polymer Edition
D Barata, E Provaggi, C van Blitterswijk, P Habibovic
Microfluidic screening platforms offer new possibilities for performing in vitro cell-based assays with higher throughput and in a setting that has the potential to closely mimic the physiological microenvironment. Integrating functional biomaterials into such platforms is a promising approach to obtain a deeper insight into the interactions occurring at the cell-material interface. The success of such an approach is, however, largely dependent on the ability to miniaturize the biomaterials as well as on the choice of the assay used to study the cell-material interactions...
November 8, 2017: Lab on a Chip
Owen G Rehrauer, Vu C Dinh, Bharat R Mankani, Gregery T Buzzard, Bradley J Lucier, Dor Ben-Amotz
The previously described optimized binary compressive detection (OB-CD) strategy enables fast hyperspectral Raman (and fluorescence) spectroscopic analysis of systems containing two or more chemical components. However, each OB-CD filter collects only a fraction of the scattered photons and the remainder of the photons are lost. Here, we present a refinement of OB-CD, the OB-CD2 strategy, in which all of the collected Raman photons are detected using a pair of complementary binary optical filters that direct photons of different colors to two photon counting detectors...
January 1, 2017: Applied Spectroscopy
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