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https://www.readbyqxmd.com/read/28644642/probing-electron-phonon-interaction-through-two-photon-interference-in-resonantly-driven-semiconductor-quantum-dots
#1
Antoine Reigue, Jake Iles-Smith, Fabian Lux, Léonard Monniello, Mathieu Bernard, Florent Margaillan, Aristide Lemaitre, Anthony Martinez, Dara P S McCutcheon, Jesper Mørk, Richard Hostein, Valia Voliotis
We investigate the temperature dependence of photon coherence properties through two-photon interference (TPI) measurements from a single quantum dot (QD) under resonant excitation. We show that the loss of indistinguishability is related only to the electron-phonon coupling and is not affected by spectral diffusion. Through these measurements and a complementary microscopic theory, we identify two independent separate decoherence processes, both of which are associated with phonons. Below 10 K, we find that the relaxation of the vibrational lattice is the dominant contribution to the loss of TPI visibility...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28644636/path-controlled-time-reordering-of-paired-photons-in-a-dressed-three-level-cascade
#2
Samir Bounouar, Max Strauß, Alexander Carmele, Peter Schnauber, Alexander Thoma, Manuel Gschrey, Jan-Hindrik Schulze, André Strittmatter, Sven Rodt, Andreas Knorr, Stephan Reitzenstein
The two-photon dressing of a "three-level ladder" system, here the ground state, the exciton, and the biexciton of a semiconductor quantum dot, leads to new eigenstates and allows one to manipulate the time ordering of the paired photons without unitary postprocessing. We show that, after spectral postselection of the single dressed states, the time ordering of the cascaded photons can be removed or conserved. Our joint experimental and theoretical study demonstrates the high potential of a "ladder" system to be a versatile source of orthogonally polarized, bunched or antibunched pairs of photons...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28643802/optogenetic-rewiring-of-thalamocortical-circuits-to-restore-function-in-the-stroke-injured-brain
#3
Kelly A Tennant, Stephanie L Taylor, Emily R White, Craig E Brown
To regain sensorimotor functions after stroke, surviving neural circuits must reorganize and form new connections. Although the thalamus is critical for processing and relaying sensory information to the cortex, little is known about how stroke affects the structure and function of these connections, or whether a therapeutic approach targeting these circuits can improve recovery. Here we reveal with in vivo calcium imaging that stroke in somatosensory cortex dampens the excitability of surviving thalamocortical circuits...
June 23, 2017: Nature Communications
https://www.readbyqxmd.com/read/28642483/masking-of-a-circadian-behavior-in-larval-zebrafish-involves-the-thalamo-habenula-pathway
#4
Qian Lin, Suresh Jesuthasan
Changes in illumination can rapidly influence behavior that is normally controlled by the circadian clock. This effect is termed masking. In mice, masking requires melanopsin-expressing retinal ganglion cells that detect blue light and project to the thalamus. It is not known whether masking is wavelength-dependent in other vertebrates, nor is it known whether the thalamus is also involved or how it influences masking. Here, we address these questions in zebrafish. We find that diel vertical migration, a circadian behavior in larval zebrafish, is effectively triggered by blue, but not by red light...
June 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28640817/an-r-camp1-07-reporter-mouse-for-cell-type-specific-expression-of-a-sensitive-red-fluorescent-calcium-indicator
#5
Philipp Bethge, Stefano Carta, Dayra A Lorenzo, Ladan Egolf, Despoina Goniotaki, Linda Madisen, Fabian F Voigt, Jerry L Chen, Bernard Schneider, Masamichi Ohkura, Junichi Nakai, Hongkui Zeng, Adriano Aguzzi, Fritjof Helmchen
Genetically encoded calcium indicators (GECIs) enable imaging of in vivo brain cell activity with high sensitivity and specificity. In contrast to viral infection or in utero electroporation, indicator expression in transgenic reporter lines is induced noninvasively, reliably, and homogenously. Recently, Cre/tTA-dependent reporter mice were introduced, which provide high-level expression of green fluorescent GECIs in a cell-type-specific and inducible manner when crossed with Cre and tTA driver mice. Here, we generated and characterized the first red-shifted GECI reporter line of this type using R-CaMP1...
2017: PloS One
https://www.readbyqxmd.com/read/28640628/oriented-gold-nanorods-and-gold-nanorod-chains-within-smectic-liquid-crystal-topological-defects
#6
Brigita Rožič, Jérôme Fresnais, Celine Molinaro, Joseph Calixte, Shivakumar Umadevi, Stephanie Lau-Truong, Nordin Felidj, Tobias Kraus, Fabrice Charra, Vincent Dupuis, Torsten Hegmann, Celine Fiorini-Debuisschert, Bruno Gallas, Emmanuelle Lacaze
We show that the use of oriented linear arrays of smectic A defects, the so-called smectic oily streaks, enables the orientation of gold nanorods (GNRs) for a large range of GNR diameters, ranging from 7 to 48 nm, and for various ligands. For the small GNRs it enables oriented end-to-end small chains of GNRs when the density is increased from around 2 GNRs/μm(2) to around 6 GNRs/μm(2). We have characterized the orientation of single GNRs by spectrophotometry and two-photon luminescence (TPL). A strongly anisotropic absorption of the composites and an on-off switching of GNR luminescence, both controlled by incident light polarization, are observed, revealing an orientation of the GNRs mostly parallel to the oily streaks...
June 22, 2017: ACS Nano
https://www.readbyqxmd.com/read/28634138/intracellular-and-transdermal-protein-delivery-mediated-by-non-covalent-interactions-with-a-synthetic-guanidine-rich-molecular-carrier
#7
Jungkyun Im, Sanket Das, Dongjun Jeong, Chang-Jin Kim, Hyun-Suk Lim, Ki Hean Kim, Sung-Kee Chung
The impermeability of the cell plasma membrane is one of the major barriers for protein transduction into mammalian cells, and it also limits the use of proteins as therapeutic agents. Protein transduction has usually been achieved based on certain invasive processes or cell penetrating peptides (CPP). Herein we report our study in which a synthetic guanidine-rich molecular carrier is used as a delivery vector for intracellular and transdermal delivery of proteins. First a sorbitol-based molecular carrier having 8 guanidine units (Sor-G8) was synthesized, and then was simply mixed with a cargo protein of varying sizes to form the non-covalent complex of carrier-cargo proteins...
June 17, 2017: International Journal of Pharmaceutics
https://www.readbyqxmd.com/read/28632960/snap-tag-based-subcellular-proteins-labeling-and-fluorescent-imaging-with-naphthalimides
#8
Chao Wang, Xinbo Song, Yi Xiao
Genetically encoded technologies provide methods for specific labeling and imaging of proteins, which is essential for the understanding of their subcellular localization and function. Herein, we employ naphthalimide, an efficient two-photon fluorophore, to develop O6-benzylguanine (BG) derivatives for specific labeling of subcellular proteins and fluorescent imaging through the SNAP-tag. The three naphthalimide-BG derivatives, TNI-BG, QNI-BG and ONI-BG are conveniently synthesized through modular "click chemistry" with high yields...
June 20, 2017: Chembiochem: a European Journal of Chemical Biology
https://www.readbyqxmd.com/read/28630487/multicolor-two-photon-imaging-of-endogenous-fluorophores-in-living-tissues-by-wavelength-mixing
#9
Chiara Stringari, Lamiae Abdeladim, Guy Malkinson, Pierre Mahou, Xavier Solinas, Isabelle Lamarre, Sébastien Brizion, Jean-Baptiste Galey, Willy Supatto, Renaud Legouis, Ana-Maria Pena, Emmanuel Beaurepaire
Two-photon imaging of endogenous fluorescence can provide physiological and metabolic information from intact tissues. However, simultaneous imaging of multiple intrinsic fluorophores, such as nicotinamide adenine dinucleotide(phosphate) (NAD(P)H), flavin adenine dinucleotide (FAD) and retinoids in living systems is generally hampered by sequential multi-wavelength excitation resulting in motion artifacts. Here, we report on efficient and simultaneous multicolor two-photon excitation of endogenous fluorophores with absorption spectra spanning the 750-1040 nm range, using wavelength mixing...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28630485/acute-administration-of-catalase-targeted-to-icam-1-attenuates-neuropathology-in-experimental-traumatic-brain-injury
#10
Evan M Lutton, Roshanak Razmpour, Allison M Andrews, Lee Anne Cannella, Young-Jin Son, Vladimir V Shuvaev, Vladimir R Muzykantov, Servio H Ramirez
Traumatic brain injury (TBI) contributes to one third of injury related deaths in the US. Treatment strategies for TBI are supportive, and the pathophysiology is not fully understood. Secondary mechanisms of injury in TBI, such as oxidative stress and inflammation, are points at which intervention may reduce neuropathology. Evidence suggests that reactive oxygen species (ROS) propagate blood-brain barrier (BBB) hyperpermeability and inflammation following TBI. We hypothesized that targeted detoxification of ROS may improve the pathological outcomes of TBI...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28630483/comprehensive-analysis-of-passive-generation-of-parabolic-similaritons-in-tapered-hydrogenated-amorphous-silicon-photonic-wires
#11
Chao Mei, Feng Li, Jinhui Yuan, Zhe Kang, Xianting Zhang, Binbin Yan, Xinzhu Sang, Qiang Wu, Xian Zhou, Kangping Zhong, Liang Wang, Kuiru Wang, Chongxiu Yu, P K A Wai
Parabolic pulses have important applications in both basic and applied sciences, such as high power optical amplification, optical communications, all-optical signal processing, etc. The generation of parabolic similaritons in tapered hydrogenated amorphous silicon photonic wires at telecom (λ ~ 1550 nm) and mid-IR (λ ≥ 2100 nm) wavelengths is demonstrated and analyzed. The self-similar theory of parabolic pulse generation in passive waveguides with increasing nonlinearity is presented. A generalized nonlinear Schrödinger equation is used to describe the coupled dynamics of optical field in the tapered hydrogenated amorphous silicon photonic wires with either decreasing dispersion or increasing nonlinearity...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28630435/in-situ-electrical-and-thermal-monitoring-of-printed-electronics-by-two-photon-mapping
#12
Francesco Pastorelli, Nicolò Accanto, Mikkel Jørgensen, Niek F van Hulst, Frederik C Krebs
Printed electronics is emerging as a new, large scale and cost effective technology that will be disruptive in fields such as energy harvesting, consumer electronics and medical sensors. The performance of printed electronic devices relies principally on the carrier mobility and molecular packing of the polymer semiconductor material. Unfortunately, the analysis of such materials is generally performed with destructive techniques, which are hard to make compatible with in situ measurements, and pose a great obstacle for the mass production of printed electronics devices...
June 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28630145/activity-dependent-trafficking-of-lysosomes-in-dendrites-and-dendritic-spines
#13
Marisa S Goo, Laura Sancho, Natalia Slepak, Daniela Boassa, Thomas J Deerinck, Mark H Ellisman, Brenda L Bloodgood, Gentry N Patrick
In neurons, lysosomes, which degrade membrane and cytoplasmic components, are thought to primarily reside in somatic and axonal compartments, but there is little understanding of their distribution and function in dendrites. Here, we used conventional and two-photon imaging and electron microscopy to show that lysosomes traffic bidirectionally in dendrites and are present in dendritic spines. We find that lysosome inhibition alters their mobility and also decreases dendritic spine number. Furthermore, perturbing microtubule and actin cytoskeletal dynamics has an inverse relationship on the distribution and motility of lysosomes in dendrites...
June 19, 2017: Journal of Cell Biology
https://www.readbyqxmd.com/read/28627888/investigation-of-drug-induced-hepatotoxicity-and-its-remediation-pathway-with-reaction-based-fluorescent-probes
#14
Dan Cheng, Wang Xu, Lin Yuan, Xiao-Bing Zhang
Drug-induced liver injury (DILI) is considered a serious problem related to public health, due to its unpredictability and acute response. The level of peroxynitrite (ONOO-) generated in liver has long been regarded as a biomarker for the prediction and measurement of DILI. Herein we present two reaction based fluorescent probes (Naph-ONOO- and Rhod-ONOO-) for ONOO- through a novel and universally applicable mechanism: ONOO- mediated deprotection of -keto caged fluorophores. Among them, Rhod-ONOO- can selectively accumulate and react in mitochondria, one of the main sources of ONOO-, with a substantial lower nano-molar sensitivity of 43 nM...
June 19, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28627559/a-luminescent-lanthanide-approach-towards-direct-visualization-of-primary-cilia-in-living-cells
#15
Hongguang Li, Rongfeng Lan, Chi-Fai Chan, Guochen Bao, Chen Xie, Pak-Ho Chu, William C S Tai, Shuai Zha, Jing-Xiang Zhang, Ka-Leung Wong
We report a direct imaging tool, HGEu001, for primary cilia in living cells, which is specific, and based on the UV light or near infrared laser (via two-photon excitation) induced long-lived europium luminescence.
June 19, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28626569/importance-of-double-resonance-effects-in-two-photon-absorption-properties-of-au25-sr-18
#16
Zhongwei Hu, Lasse Jensen
The two-photon absorption (TPA) cross-sections of small thiolate-protected gold clusters have been shown to be much larger than typical small organic molecules. In comparison with larger nanoparticles, their TPA cross-sections per gold atom are also found to be larger. Theoretical simulations have suggested that the large enhancement of these TPA cross-sections comes from a one-photon double-resonance mechanism. However, it remains difficult to simulate TPA cross-sections of thiolate-protected gold clusters due to their large system size and a high density of states...
June 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28625064/an-off-on-two-photon-fluorescent-probe-for-tracking-cell-senescence-in-vivo
#17
Beatriz Lozano-Torres, Irene Galiana, Miguel Rovira, Eva Garrido, Selim Chaib, Andrea Bernardos, Daniel Muñoz-Espín, Manuel Serrano, Ramón Martínez-Máñez, Félix Sancenón
A naphthalimide-based two-photon probe (AHGa) for the detection of cell senescence is designed. The probe contains a naphthalimide core, an l-histidine methyl ester linker, and an acetylated galactose bonded to one of the aromatic nitrogen atoms of the l-histidine through a hydrolyzable N-glycosidic bond. Probe AHGa is transformed into AH in senescent cells resulting in an enhanced fluorescent emission intensity. In vivo detection of senescence is validated in mice bearing tumor xenografts treated with senescence-inducing chemotherapy...
June 23, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28624080/impact-of-the-homogenization-process-on-the-structure-and-antioxidant-properties-of-chitosan-lignin-composite-films
#18
Kevin Crouvisier-Urion, Aurélie Lagorce-Tachon, Camille Lauquin, Pascale Winckler, Wirongrong Tongdeesoontorn, Sandra Domenek, Frédéric Debeaufort, Thomas Karbowiak
This work investigated the impact of two homogenization treatments, High Shear (HS) and High Pressure (HP), on the structure and antioxidant activity of chitosan-lignin bio-composite films. Laser light scattering analysis revealed that smaller lignin particles were obtained after HP processing, around 0.6μm, compared to HS treatment, between 2.5 and 5μm. Moreover, these particles were more homogeneously distributed in the chitosan film matrix after HP process, while some aggregates remained after HS treatment, as highlighted by two-photon microscopy...
December 1, 2017: Food Chemistry
https://www.readbyqxmd.com/read/28623341/metabolic-fingerprinting-of-bacteria-by-fluorescence-lifetime-imaging-microscopy
#19
Arunima Bhattacharjee, Rupsa Datta, Enrico Gratton, Allon I Hochbaum
Bacterial populations exhibit a range of metabolic states influenced by their environment, intra- and interspecies interactions. The identification of bacterial metabolic states and transitions between them in their native environment promises to elucidate community behavior and stochastic processes, such as antibiotic resistance acquisition. In this work, we employ two-photon fluorescence lifetime imaging microscopy (FLIM) to create a metabolic fingerprint of individual bacteria and populations. FLIM of autofluorescent reduced nicotinamide adenine dinucleotide (phosphate), NAD(P)H, has been previously exploited for label-free metabolic imaging of mammalian cells...
June 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28622724/porphyrin-arch-tapes-synthesis-contorted-structures-and-full-conjugation
#20
Norihito Fukui, Taeyeon Kim, Dongho Kim, Atsuhiro Osuka
Porphyrin tapes possessing meso-meso β-β β-β triple direct linkages have been targets of extensive studies because of their fully conjugated characteristic π-electronic networks. In this paper, we report porphyrin arch-tapes that bear additional carbonyl group(s) or methylene group(s) inserted between one of the β-β linkage(s) of the porphyrin tapes. The carbonyl-inserted porphyrin arch-tapes were efficiently synthesized by double fusion reactions of β-to-β carbonyl-bridged porphyrin oligomers with DDQ and Sc(OTf)3, and were converted to the methylene-bridged porphyrin arch-tapes via Luche reduction with NaBH4 and CeCl3 followed by ionic hydrogenation with HBF4·OEt2 and BH3·NEt3...
June 23, 2017: Journal of the American Chemical Society
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