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R Stockill, M J Stanley, L Huthmacher, E Clarke, M Hugues, A J Miller, C Matthiesen, C Le Gall, M Atatüre
Quantum entanglement between distant qubits is an important feature of quantum networks. Distribution of entanglement over long distances can be enabled through coherently interfacing qubit pairs via photonic channels. Here, we report the realization of optically generated quantum entanglement between electron spin qubits confined in two distant semiconductor quantum dots. The protocol relies on spin-photon entanglement in the trionic Λ system and quantum erasure of the Raman-photon path information. The measurement of a single Raman photon is used to project the spin qubits into a joint quantum state with an interferometrically stabilized and tunable relative phase...
July 7, 2017: Physical Review Letters
Luca S Costanzo, Antonio S Coelho, Nicola Biagi, Jaromír Fiurášek, Marco Bellini, Alessandro Zavatta
Strong nonlinearity at the single photon level represents a crucial enabling tool for optical quantum technologies. Here we report on experimental implementation of a strong Kerr nonlinearity by measurement-induced quantum operations on weak quantum states of light. Our scheme coherently combines two sequences of single photon addition and subtraction to induce a nonlinear phase shift at the single photon level. We probe the induced nonlinearity with weak coherent states and characterize the output non-Gaussian states with quantum state tomography...
July 7, 2017: Physical Review Letters
Jessica E S Sutcliffe, Christopher Thrasivoulou, Thomas E Serena, Leigh Madden, Toby Richards, Anthony R J Phillips, David L Becker
Chronic wounds are a growing problem worldwide with no effective therapeutic treatments available. Our objective was to understand the composition of the dermal tissue surrounding venous leg ulcers and diabetic foot ulcers (DFU). We used novel 2-photon imaging techniques alongside classical histology to examine biopsies from the edges of two common types of chronic wound, venous leg ulcers and DFU. Compared to normal intact skin, we found that collagen levels are significantly reduced throughout the dermis of venous leg ulcer biopsies and DFU, with a reduction in both fibril thickness and abundance...
July 20, 2017: International Wound Journal
Moritz Brehm, Martyna Grydlik
In this review, we report on fabrication paths, challenges, and emerging solutions to integrate group-IV epitaxial quantum dots (QDs) as active light emitters into the existing standard Si technology. Their potential as laser gain material for the use of optical intra- and inter-chip interconnects as well as possibilities to combine a single-photon-source-based quantum cryptographic means with Si technology will be discussed. We propose that the mandatory addressability of the light emitters can be achieved by a combination of organized QD growth assisted by templated self-assembly, and advanced inter-QD defect engineering to boost the optical emissivity of group-IV QDs at room-temperature...
July 21, 2017: Nanotechnology
Kengo Inada, Yoshiko Tsuchimoto, Hokto Kazama
How cell-type-specific physiological properties shape neuronal functions in a circuit remains poorly understood. We addressed this issue in the Drosophila mushroom body (MB), a higher olfactory circuit, where neurons belonging to distinct glomeruli in the antennal lobe feed excitation to three types of intrinsic neurons, α/β, α'/β', and γ Kenyon cells (KCs). Two-photon optogenetics and intracellular recording revealed that whereas glomerular inputs add similarly in all KCs, spikes were generated most readily in α'/β' KCs...
July 19, 2017: Neuron
Joe Y Chang, Vivek Verma, Ming Li, Wencheng Zhang, Ritsuko Komaki, Charles Lu, Pamela K Allen, Zhongxing Liao, James Welsh, Steven H Lin, Daniel Gomez, Melenda Jeter, Michael O'Reilly, Ronald X Zhu, Xiaodong Zhang, Heng Li, Radhe Mohan, John V Heymach, Ara A Vaporciyan, Stephen Hahn, James D Cox
Importance: Proton beam radiotherapy (PBT) has the potential to reduce toxic effects in the definitive management of locally advanced non-small-cell lung cancer (NSCLC), but long-term prospective data are lacking. Objective: To report the final (5-year) results of a prospective study evaluating concurrent chemotherapy and high-dose PBT to treat unresectable stage III NSCLC. Design, Setting, and Participants: In this open-label, single-group assignment study, with median follow-up of 27...
July 20, 2017: JAMA Oncology
Kel-Meng See, Fan-Cheng Lin, Jer-Shing Huang
We present a two-dimensional plasmonic Doppler grating (PDG) for broadband and azimuthal angle-resolved nanophotonic applications. The PDG consists of a set of non-concentric circular rings mimicking the wavefronts of a moving point source that exhibits the Doppler effect and thereby offers a continuous azimuthal angle-dependent lattice momentum for photon-plasmon coupling. The center and span of the working frequency window are fully designable for optimal performance in specific applications. We detail the design, fabrication and optical characterization of the PDG...
July 20, 2017: Nanoscale
Yujin Zhang, Jiancai Leng
The development of fluorescent sensors for Hg(2+) has attracted much attention due to the well-known adverse effects of mercury on biological health. In the present work, the optical properties of two newly-synthesized Hg(2+) chemosensors based on the coumarin-rhodamine system (named Pro1 and Pro2) were systematically investigated using time-dependent density functional theory. It is shown that Pro1 and Pro2 are effective ratiometric fluorescent Hg(2+) probes, which recognize Hg(2+) by Förster resonance energy transfer and through bond energy transfer mechanisms, respectively...
July 20, 2017: Sensors
Hao Han, Hao Gao, Lei Xing
Excessive radiation exposure is still a major concern in 4D cone-beam computed tomography (4D-CBCT) due to its prolonged scanning duration. Radiation dose can be effectively reduced by either under-sampling the x-ray projections or reducing the x-ray flux. However, 4D-CBCT reconstruction under such low-dose protocols is prone to image artifacts and noise. In this work, we propose a novel joint regularization-based iterative reconstruction method for low-dose 4D-CBCT. To tackle the under-sampling problem, we employ spatiotemporal tensor framelet (STF) regularization to take advantage of the spatiotemporal coherence of the patient anatomy in 4D images...
July 20, 2017: Physics in Medicine and Biology
Mohammad Izadifar, Paul Babyn, Michael E Kelly, Dean Chapman, Xiongbiao Chen
Three-dimensional (3D)-bioprinting techniques may be used to modulate electrical/mechanical properties and porosity of hydrogel constructs for fabrication of suitable cardiac implants. Notably, characterization of these properties after implantation remains a challenge, raising the need for the development of novel quantitative imaging techniques for monitoring hydrogel implant behavior in-situ. This study aims to (i) assess the influence of hydrogel bioprinting patterns on electrical/mechanical behavior of cardiac implants based on a 3D-printing technique and (ii) investigate the potential of synchrotron X-ray phase contrast computed tomography (PCI-CT) for estimating elastic modulus/impedance/porosity and microstructural features of 3D-printed cardiac implants in-situ via an ex-vivo study...
July 20, 2017: Tissue Engineering. Part C, Methods
Te-Wei Chang, Xinhao Wang, Amirreza Mahigir, Georgios Veronis, Gang Logan Liu, Manas Ranjan Gartia
Many single-molecule (SM) label-free techniques such as scanning probe microscopies (SPM) and magnetic force spectroscopies (MFS) provide high resolution surface topography information, but lack chemical information. Typical surface enhanced Raman spectroscopy (SERS) systems provide chemical information on the analytes, but lack spatial resolution. In addition, a challenge in SERS sensors is to bring analytes into the so-called "hot spots" (locations where the enhancement of electromagnetic field amplitude is larger than 10(3))...
July 20, 2017: ACS Sensors
Eero Hippeläinen, Teemu Mäkelä, Touko Kaasalainen, Erna Kaleva
BACKGROUND: Developments in single photon emission tomography instrumentation and reconstruction methods present a potential for decreasing acquisition times. One of such recent options for myocardial perfusion imaging (MPI) is IQ-SPECT. This study was motivated by the inconsistency in the reported ejection fraction (EF) and left ventricular (LV) volume results between IQ-SPECT and more conventional low-energy high-resolution (LEHR) collimation protocols. IQ-SPECT and LEHR quantitative results were compared while the equivalent number of iterations (EI) was varied...
December 2017: EJNMMI Physics
Joseph B Dechery, Jason N MacLean
Temporal codes are theoretically powerful encoding schemes, but their precise form in neocortex remains unknown in part because of the large number of possible codes and the difficulty in disambiguating informative spikes from statistical noise. A biologically plausible and computationally powerful temporal coding scheme is the Hebbian assembly phase sequence (APS), which predicts reliable propagation of spikes between functionally related assemblies of neurons. Here, we sought to measure the inherent capacity of neocortical networks to produce reliable sequences of spikes, as would be predicted by an APS code...
July 19, 2017: Journal of Neurophysiology
Lili Lv, Xiangsheng Han, Lu Zong, Mingjie Li, Jun You, Xiaochen Wu, Chaoxu Li
Silk, one of the strongest natural biopolymers, was hybridized with Kevlar, one of the strongest synthetic polymers, through a biomimetic nanofibrous strategy. Regenerated silk materials have outstanding properties in transparency, biocompatibility, biodegradability and sustainability, and promised the applications as diverse as in pharmaceutics, electronics, photonic devices and membranes. To compete with super mechanic properties of their natural counterpart, regenerated silk materials have been hybridized with inorganic fillers such as graphene and carbon nanotubes, but frequently losing essential mechanic flexibility...
July 19, 2017: ACS Nano
Chris Ritchie, George Vamvounis, Hamid Soleimaninejad, Trevor A Smith, Evan J Bieske, Viktoras Dryza
The spectroscopic properties of poly(methyl methacrylate) polymer films doped with two kinds of photochromic molecular switches are investigated. A green-fluorescent sulfonyl diarylethene (P1) is combined with either a non-fluorescent diarylethene (P2) or red-fluorescent spiropyran (P3). Photoswitching between the colorless and colored isomers (P1: o-BTFO4 ↔ c-BTFO4, P2: o-DTE ↔ c-DTE, P3: SP ↔ MC) enables the P1 + P2 and P1 + P3 films to be cycled through three distinct states. From the initial state (o-BTFO4 + o-DTE/SP), irradiation with UV light generates the second state (c-BTFO4 + c-DTE/MC), where c-BTFO4 → c-DTE/MC energy transfer is established...
July 19, 2017: Physical Chemistry Chemical Physics: PCCP
Heonoh Kim, Sang Min Lee, Osung Kwon, Han Seb Moon
We present two-photon interference experiments with polarization-entangled photon pairs in a polarization-based Franson-type interferometer. Although the two photons do not meet at a common beamsplitter, a phase-insensitive Hong-Ou-Mandel type two-photon interference peak and dip fringes are observed, resulting from the two-photon interference effect between two indistinguishable two-photon probability amplitudes leading to a coincidence detection. A spatial quantum beating fringe is also measured for nondegenerate photon pairs in the same interferometer, although the two-photon states have no frequency entanglement...
July 18, 2017: Scientific Reports
L Ondič, M Varga, I Pelant, J Valenta, A Kromka, R G Elliman
Light extraction from a thin planar layer can be increased by introducing a two-dimensional periodic pattern on its surface. This structure, the so-called photonic crystal (PhC) slab, then not only enhances the extraction efficiency of light but can direct the extracted emission into desired angles. Careful design of the structures is important in order to have a spectral overlap of the emission with extraction (leaky) modes. We show that by fabricating PhC slabs with optimized dimensions from silicon nanocrystals (SiNCs) active layers, the extraction efficiency of vertical light emission from SiNCs at a particular wavelength can be enhanced ∼ 11 times compared to that of uncorrugated SiNCs-rich layer...
July 18, 2017: Scientific Reports
Takamasa Ikeda, Kenji Sakota, Hiroshi Sekiya
Isomerization between two hydrogen-bonded (H-bonded) isomers of 5-hydroxyindole-(tert-butyl alcohol)1 cluster cations ([5HI-(t-BuOH)1](+)) was investigated in the gas phase. In the S0 state, jet-cooled 5HI-(t-BuOH)1 has two structural isomers, 5HI(OH)-(t-BuOH)1 and 5HI(NH)-(t-BuOH)1, in which the t-BuOH molecule is bound to the OH or the NH group of 5HI. The IR photodissociation spectrum of [5HI-(t-BuOH)1](+) generated by two-color resonant two-photon ionization (2C-R2PI) via the S1-S0 origin of 5HI(NH)-(t-BuOH)1 provided evidence of both [5HI(OH)-(t-BuOH)1](+) and [5HI(NH)-(t-BuOH)1](+) coexisting in the D0 state, indicating that [5HI(NH)-(t-BuOH)1](+) isomerizes to [5HI(OH)-(t-BuOH)1](+) after 2C-R2PI of 5HI(NH)-(t-BuOH)1...
July 18, 2017: Journal of Physical Chemistry. A
Andréanne Lapointe, Houda Bahig, Danis Blais, Hugo Bouchard, Édith Filion, Jean-François Carrier, Stéphane Bedwani
PURPOSE: There is an increasing interest in the evaluation of lung function from physiological images in radiation therapy treatment planning to reduce the extent of post-radiation toxicities. The purpose of this work is to retrieve reliable functional information from contrast-enhanced dualenergy computed tomography (DECT) for new applications in radiation therapy. The functional information obtained by DECT is also compared with other methods using single energy CT (SECT) and single-photon emission computed tomography (SPECT) with CT...
July 18, 2017: Medical Physics
Barbara Chiavarino, Maria Elisa Crestoni, Simonetta Fornarini, Debora Scuderi, Jean-Yves Salpin
The complex obtained by the reaction of cisplatin and 2'-deoxyadenosine-5'-monophosphate (5'-dAMP) in water has been isolated and detected by electrospray ionization mass spectrometry. The so-formed cis-[PtCl(NH3)2(5'-dAMP)](+) complex has been studied in detail by infrared multiple photon dissociation (IRMPD) spectroscopy in two spectral ranges, namely, 700-1900 and 2800-3800 cm(-1), backed by quantum-chemical calculations at the B3LYP/LACV3P/6-311G** level of theory. In agreement with the computational results, the vibrational spectroscopic characterization of cis-[PtCl(NH3)2(5'-dAMP)](+) shows that the sampled ionic population comprises two major isomers, differentiated in the X-H stretching region by their distinct fragmentation patterns...
July 18, 2017: Inorganic Chemistry
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