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C Leroux, L C G Govia, A A Clerk
We present and analyze a method where parametric (two-photon) driving of a cavity is used to exponentially enhance the light-matter coupling in a generic cavity QED setup, with time-dependent control. Our method allows one to enhance weak-coupling systems, such that they enter the strong coupling regime (where the coupling exceeds dissipative rates) and even the ultrastrong coupling regime (where the coupling is comparable to the cavity frequency). As an example, we show how the scheme allows one to use a weak-coupling system to adiabatically prepare the highly entangled ground state of the ultrastrong coupling system...
March 2, 2018: Physical Review Letters
Lisa Menegazzo, Valentina Scattolini, Roberta Cappellari, Benedetta Maria Bonora, Mattia Albiero, Mario Bortolozzi, Filippo Romanato, Giulio Ceolotto, Saula Vigili de Kreutzeberg, Angelo Avogaro, Gian Paolo Fadini
AIMS: Diabetes is associated with an excess release of neutrophil extracellular traps (NETs) and an enhanced NETosis, a neutrophil cell death programme instrumental to anti-microbial defences, but also involved in tissue damage. We herein investigated whether the antidiabetic drug metformin protects against NETosis. METHODS: We measured NET components in the plasma of patients with pre-diabetes who were randomized to receive metformin or placebo for 2 months. To control for the effect on glucose, we also measured NET components in the plasma of patients with type 2 diabetes before and after treatment with insulin or dapagliflozin...
March 15, 2018: Acta Diabetologica
Fernanda Ramos-Gomes, Julia Bode, Alyona Sukhanova, Svetlana V Bozrova, Mara Saccomano, Miso Mitkovski, Julia Eva Krueger, Anja K Wege, Walter Stuehmer, Pavel S Samokhvalov, Daniel Baty, Patrick Chames, Igor Nabiev, Frauke Alves
Early detection of malignant tumours and, especially, micrometastases and disseminated tumour cells is still a challenge. In order to implement highly sensitive diagnostic tools we demonstrate the use of nanoprobes engineered from nanobodies (single-domain antibodies, sdAbs) and fluorescent quantum dots (QDs) for single- and two-photon detection and imaging of human micrometastases and disseminated tumour cells in ex vivo biological samples of breast and pancreatic metastatic tumour mouse models expressing human epidermal growth factor receptor 2 (HER2) or carcinoembryonic antigen (CEA)...
March 15, 2018: Scientific Reports
Jens Neumann, Sophie Henneberg, Susanne von Kenne, Niklas Nolte, Andreas J Müller, Burkhart Schraven, Michael W Görtler, Klaus G Reymann, Matthias Gunzer, Monika Riek-Burchardt
Inflammation plays an important role in the pathogenesis of ischemic stroke including an acute and prolonged inflammatory process. The role of neutrophil granulocytes as first driver of the immune reaction from the blood site is under debate due to controversial findings. In bone marrow chimeric mice we were able to study the dynamics of tdTomato-expressing neutrophils and GFP-expressing microglia after photothrombosis using intravital two-photon microscopy. We demonstrate the infiltration of neutrophils into the brain parenchyma and confirm a long-lasting contact between neutrophils and microglia as well as an uptake of neutrophils by microglia clearing the brain from peripheral immune cells...
2018: PloS One
Yuly Vesga, Carlos Diaz, Jeanne Crassous, Florencio E Hernandez
Herein, we report on the theoretical-experimental analysis of the two photon absorption and circular dichroism spectra of 1-(2-pyridyl)-4-methoxy-carbo[6]helicene derivative (P6). The primary outcomes of our investigation on this particular helicene derivative with a donor-acceptor motif on one end led to two important conclusions: 1) The lengthening of the π-electron delocalization within the helical core of P6 predominantly increases the contribution of the magnetic transition dipole moment to the TPCD signal; 2) The electric transition quadrupole moment contribution to the TPCD signal is enhanced by the intramolecular charge transfer (ICT) produced by the donor-acceptor combination on one end of the molecule...
March 15, 2018: Journal of Physical Chemistry. A
S F Cooper, Z Burkley, A D Brandt, C Rasor, D C Yost
We demonstrate a 650 mW 243 nm continuous-wave laser coupled to a linear optical enhancement cavity. The enhancement cavity can maintain >30  W of intracavity power for 1 h of continuous operation without degradation. This system has sufficient power for a demonstration of two-photon laser cooling of hydrogen and may be useful for experiments on other simple two-body atomic systems.
March 15, 2018: Optics Letters
L Ortiz-Gutiérrez, L F Muñoz-Martínez, D F Barros, J E O Morales, R S N Moreira, N D Alves, A F G Tieco, P L Saldanha, D Felinto
Superradiance in an ensemble of atoms leads to the collective enhancement of radiation in a particular mode shared by the atoms in their spontaneous decay from an excited state. The quantum aspects of this phenomenon are highlighted when such collective enhancement is observed in the emission of a single quantum of light. Here we report a further step in exploring experimentally the nonclassical features of superradiance by implementing the process not only with single excitations, but also in a two-excitation state...
February 23, 2018: Physical Review Letters
Jin-Wen Liu, Yu-Min Wang, Chong-Hua Zhang, Lu-Ying Duan, Zheng Li, Ru-Qin Yu, Jian-Hui Jiang
Unique physicochemical characteristics of graphitic carbon nitride (g-CN) nanosheets suit them a useful tool for two-photon fluorescence bioimaging. Current g-CN nanosheets based imaging probes typically use the "always-on" design strategies, which may suffer from increased fluorescence background and limited contrast. To advance corresponding applications, g-CN nanosheets based activatable two-photon fluorescence probes remain to be explored. For the first time, we developed an activatable two-photon fluorescence probe, constructed from a nanoassembly of g-CN nanosheets and hyaluronic acid (HA)-gold nanoparticles (HA-AuNPs), for detection and imaging of hyaluronidase (HAase) in cancer cells...
March 15, 2018: Analytical Chemistry
Shulian Wu, Yudian Huang, Qinggong Tang, Zhifang Li, Hannah Horng, Jiatian Li, Zaihua Wu, Yu Chen, Hui Li
Preoperative neoadjuvant treatment in locally advanced breast cancer is recognized as an effective adjuvant therapy, as it improves treatment outcomes. However, the potential complications remain a threat, so there is an urgent clinical need to assess both the tumor response and changes in its microenvironment using non-invasive and precise identification techniques. Here, two-photon microscopy was employed to detect morphological alterations in breast cancer progression and recession throughout chemotherapy...
March 1, 2018: Biomedical Optics Express
Angelo Forli, Dania Vecchia, Noemi Binini, Francesca Succol, Serena Bovetti, Claudio Moretti, Francesco Nespoli, Mathias Mahn, Christopher A Baker, McLean M Bolton, Ofer Yizhar, Tommaso Fellin
Sensory information is encoded within the brain in distributed spatiotemporal patterns of neuronal activity. Understanding how these patterns influence behavior requires a method to measure and to bidirectionally perturb with high spatial resolution the activity of the multiple neuronal cell types engaged in sensory processing. Here, we combined two-photon holography to stimulate neurons expressing blue light-sensitive opsins (ChR2 and GtACR2) with two-photon imaging of the red-shifted indicator jRCaMP1a in the mouse neocortex in vivo...
March 13, 2018: Cell Reports
Krzysztof Kucharz, Martin Lauritzen
Cortical spreading depolarization waves, the cause underlying migraine aura, are also the markers and mechanism of pathology in the acutely injured human brain. Propagation of spreading depolarization wave uniquely depends on the interaction between presynaptic and postsynaptic glutamate N-methyl-d-aspartate receptors (NMDARs). In the normally perfused brain, even a single wave causes a massive depolarization of neurons and glia, which results in transient loss of neuronal function and depression of the ongoing electrocorticographic activity...
March 12, 2018: Brain: a Journal of Neurology
Fang Zhang, W Mx, Zhengping Wang, Kezhen Han, Xiaojuan Liu, Xinguang Xu
As the cousins of graphene, i.e. same group IVA element, the nonlinear absorption properties of silicene nanosheets were rarely studied. In this paper, we successfully exfoliated the two-dimensional silicene nanosheets from bulk silicon crystal using liquid phase exfoliation method. The nonlinear absorption properties of silicene nanosheets were systemically investigated for the first time, as we have known. Silicene performed exciting saturable absorption and two photon absorption behavior. The lower saturable intensity and larger two photon absorption coefficient at 532 nm excitation indicates that silicene has potential application in ultrafast lasers and optical limiting devices, especially in visible waveband...
March 14, 2018: Nanotechnology
Zhiyi Liu, Dimitra Pouli, Carlo A Alonzo, Antonio Varone, Sevasti Karaliota, Kyle P Quinn, Karl Münger, Katia P Karalis, Irene Georgakoudi
Monitoring subcellular functional and structural changes associated with metabolism is essential for understanding healthy tissue development and the progression of numerous diseases, including cancer, diabetes, and cardiovascular and neurodegenerative disorders. Unfortunately, established methods for this purpose either are destructive or require the use of exogenous agents. Recent work has highlighted the potential of endogenous two-photon excited fluorescence (TPEF) as a method to monitor subtle metabolic changes; however, mechanistic understanding of the connections between the detected optical signal and the underlying metabolic pathways has been lacking...
March 2018: Science Advances
Jue Hou, Joshua Williams, Elliot Botvinick, Eric Potma, Bruce J Tromberg
Label-free non-linear optical microscopy (NLOM) based on two-photon excited fluorescence (TPEF) from cofactors Nicotinamide Adenine Dinucleotide (NADH) and Flavin Adenine Dinucleotide (FAD+) is widely used for high-resolution cellular redox imaging. In this work, we combined three, label-free NLOM imaging methods to quantitatively characterize breast cancer cells and their relative invasive potential: 1) TPEF optical redox ratio (ORR = FAD+/NADH + FAD+), 2) coherent Raman scattering (CRS) of cellular lipids, and 3) second harmonic generation (SHG) of extracellular matrix (ECM) collagen...
March 13, 2018: Cancer Research
Wankun L Li, Monica W Chu, An Wu, Yusuke Suzuki, Itaru Imayoshi, Takaki Komiyama
The rodent olfactory bulb incorporates thousands of newly generated inhibitory neurons daily throughout adulthood, but the role of adult neurogenesis in olfactory processing is not fully understood. Here we adopted a genetic method to inducibly suppress adult neurogenesis and investigated its effect on behavior and bulbar activity. Mice without young adult-born neurons (ABNs) showed normal ability in discriminating very different odorants but were impaired in fine discrimination. Furthermore, two-photon calcium imaging of mitral cells (MCs) revealed that the ensemble odor representations of similar odorants were more ambiguous in the ablation animals...
March 13, 2018: ELife
Hui Wang, Bin Fang, Le Zhou, Di Li, Lin Kong, Kajsa Uvdal, Zhangjun Hu
A two-photon active probe for physiological copper (Cu2+ ) detection is expected to play an important role in monitoring biological metabolism. Herein, a novel Schiff base derivative (E)-2,2'-((4-((4-(diethylamino)-2-hydroxybenzylidene)amino)phenyl)azanediyl)bis(ethan-1-ol) (L) with remarkable two-photon activity was developed and synthetically investigated. L presents high selectivity and sensitivity for Cu2+ sensing in ethanol/HEPES buffer (v/v, 1 : 1), which is accompanied by the fluorescence switching "off" and subsequently "on" with the addition of EDTA...
March 13, 2018: Organic & Biomolecular Chemistry
Anirban Roy, Robert Seidel, Gaurav Kumar, Stephen E Bradforth
Direct measurements of the valence ionization energies and the reorganization energies of the three aromatic amino acids, L-Tyrosine, L-Tryptophan, and L-Phenylalanine in aqueous solution using the liquid microjet technique and two different photoemission methods - X-ray photoelectron spectroscopy (XPS) at 175 eV photon energy and resonant two-photon ionization (R2PI) using 2 x 267 nm (2 x 4.64 eV) UV laser light are reported. L-Tryptophan has the lowest vertical ionization energy, 7.3 eV, followed by Tyrosine (7...
March 12, 2018: Journal of Physical Chemistry. B
F H Wang, K Bae, Z W Huang, J M Xue
For obtaining high-resolution macroscopical anatomical information and high sensitivity microscopical optical signals, it is highly desirable to develop dual-modality magnetic resonance imaging (MRI) and fluorescent probes in medical imaging simultaneously. In this study, Gd2 O3 nanoparticles were modified with two-photon graphene quantum dots (GQD), integrating a magnetic resonance imaging (MRI) contrast agent with two-photon imaging functionality into one nanoprobe. A photoluminescence study indicated that the GQD modification process integrated MRI properties with both one-photon and two-photon imaging properties...
March 12, 2018: Nanoscale
Patrick A Robertson, Luigi Villani, Uresha L M Dissanayake, Luke F Duncan, Belinda M Abbott, David J D Wilson, Evan G Robertson
The electronic spectra of 2-bromoethylbenzene and its chloro and fluoro analogues have been recorded by resonant two-photon ionisation (R2PI) spectroscopy. Anti and gauche conformers have been assigned by rotational band contour analysis and IR-UV ion depletion spectroscopy in the CH region. Hydrate clusters of the anti conformers have also been observed, allowing the role of halocarbons as hydrogen bond acceptors to be examined in this context. The donor OH stretch of water bound to chlorine is red-shifted by 36 cm-1 , or 39 cm-1 in the case of bromine...
March 12, 2018: Physical Chemistry Chemical Physics: PCCP
Ralitza Staneva, Jorge Barbazan, Anthony Simon, Danijela Matic Vignjevic, Denis Krndija
Cell migration is a process that ensures correct cell localization and function in development and homeostasis. In disease such as cancer, cells acquire an upregulated migratory capacity that leads to their dissemination throughout the body. Live imaging of cell migration allows for better understanding of cell behaviors in development, adult tissue homeostasis and disease. We have optimized live imaging procedures to track cell migration in adult murine tissue explants derived from: (1) healthy gut; (2) primary intestinal carcinoma; and (3) the liver, a common metastatic site...
2018: Methods in Molecular Biology
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