44,100 results match your criteria Optics Express [Journal]


Diel versus time-integrated (daily) photosynthesis and irradiance relationships of coral reef organisms and communities.

PLoS One 2018 17;13(12):e0208607. Epub 2018 Dec 17.

Coral Reef Ecology and Optics Laboratory (CREOL), Bermuda Institute of Ocean Sciences (BIOS), St. George's, Bermuda.

The most important source of energy to tropical shallow water coral reefs is light, the transformation of which ultimately limits reef biomass and growth. Therefore, measurements of productivity (primary production, P) for benthic reef organisms and communities are critical to understand reef functioning. Short-term (minutes to hours) P measurements of reef photosynthesizers virtually always produce the classic hyperbolic tangent (or similar) P-E (irradiance) relationship, with P rapidly rising to a saturation point as E increases. Read More

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December 2018

Selective S Cone Damage and Retinal Remodeling Following Intense Ultrashort Pulse Laser Exposures in the Near-Infrared.

Invest Ophthalmol Vis Sci 2018 Dec;59(15):5973-5984

Center for Visual Science, University of Rochester, Rochester, New York, United States.

Purpose: Infrared ultrashort pulse lasers are becoming increasingly popular for applications in the living eye. However, safety standards are not yet well established. Here we investigate retinal damage close to threshold for this pulse regime in the living macaque eye. Read More

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December 2018

Nonlinearity-tailored fiber laser technology for low-noise, ultra-wideband tunable femtosecond light generation.

Photonics Res 2017 Dec 27;5(6):750-761. Epub 2017 Nov 27.

Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.

The emission wavelength of a laser is physically predetermined by the gain medium used. Consequently, arbitrary wavelength generation is a fundamental challenge in the science of light. Present solutions include optical parametric generation, requiring complex optical setups and spectrally sliced supercontinuum, taking advantage of a simpler fiber technology: a fixed-wavelength pump laser pulse is converted into a spectrally very broadband output, from which the required resulting wavelength is then optically filtered. Read More

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December 2017

MCmatlab: an open-source, user-friendly, MATLAB-integrated three-dimensional Monte Carlo light transport solver with heat diffusion and tissue damage.

J Biomed Opt 2018 Dec;23(12):1-6

Technical University of Denmark, Department of Photonics Engineering, Roskilde, Denmark.

While there exist many Monte Carlo (MC) programs for solving the radiative transfer equation (RTE) in biological tissues, we have identified a need for an open-source MC program that is sufficiently user-friendly for use in an education environment, in which detailed knowledge of compiling or UNIX command-line cannot be assumed. Therefore, we introduce MCmatlab, an open-source codebase thus far consisting of (a) a fast three-dimensional MC RTE solver and (b) a finite-element heat diffusion and Arrhenius-based thermal tissue damage simulator, both run in MATLAB. The kernel for both of these solvers is written in parallelized C and implemented as MATLAB MEX functions, combining the speed of C with the familiarity and versatility of MATLAB. Read More

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December 2018
7 Reads

The Rb 3Π state: Observation and analysis.

J Chem Phys 2018 Dec;149(22):224303

Physics Department, Temple University, Philadelphia, Pennsylvania 19122-6082, USA.

This paper reports observations and analysis of the Rb 3Π state. A total of 323 rovibrational term values spanning the range of the rotational quantum number = 7 through 77 and the vibrational quantum number = 2 through 23 (about 1/3 of the potential well depth) were measured using the optical-optical double resonance technique. The term values are simulated within a model of a piece-wise multi-parameter potential energy function based on the generalized splines. Read More

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December 2018

Dynamic Changes of Retinal Microaneurysms in Diabetes Imaged With In Vivo Adaptive Optics Optical Coherence Tomography.

Invest Ophthalmol Vis Sci 2018 Dec;59(15):5932-5940

Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria.

Purpose: To prospectively monitor microaneurysms (MAs) in three dimensions using adaptive optics optical coherence tomography (AOOCT).

Methods: Patients with diabetes mellitus and parafoveal MAs were included in this longitudinal study. At baseline, MAs were identified in standard fluorescein angiography (FA) and subsequently imaged with an AOOCT prototype, incorporated into an AO fundus camera (RTX1, Imagine Eyes) device. Read More

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December 2018
2 Reads

Structural and functional insight into serine hydroxymethyltransferase from Helicobacter pylori.

PLoS One 2018 14;13(12):e0208850. Epub 2018 Dec 14.

Laboratory of Optics and Biosciences, Ecole polytechnique, CNRS, INSERM, Université Paris Saclay, Palaiseau, France.

Serine hydroxymethyltransferase (SHMT), encoded by the glyA gene, is a ubiquitous pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the formation of glycine from serine. The thereby generated 5,10-methylene tetrahydrofolate (MTHF) is a major source of cellular one-carbon units and a key intermediate in thymidylate biosynthesis. While in virtually all eukaryotic and many bacterial systems thymidylate synthase ThyA, SHMT and dihydrofolate reductase (DHFR) are part of the thymidylate/folate cycle, the situation is different in organisms using flavin-dependent thymidylate synthase ThyX. Read More

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December 2018

Calculation of hot spots for protein-protein interaction in p53/PMI-MDM2/MDMX complexes.

J Comput Chem 2018 Dec 14. Epub 2018 Dec 14.

School of Physics and Material Science, Shanghai Engineering Research Center of Molecular Therapeutics & New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China.

The recently developed MM/GBSA_IE method is applied to computing hot and warm spots in p53/PMI-MDM2/MDMX protein-protein interaction systems. Comparison of the calculated hot (>2 kcal/mol) and warm spots (>1 kcal/mol) in P53 and PMI proteins interacting with MDM2 and MDMX shows a good quantitative agreement with the available experimental data. Further, our calculation predicted hot spots in MDM2 and MDMX proteins in their interactions with P53 and PMI and they help elucidate the interaction mechanism underlying this important PPI system. Read More

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December 2018

Illusion Optics: Disguising with Ordinary Dielectric Materials.

Adv Mater 2018 Dec 13:e1805106. Epub 2018 Dec 13.

Centre for Optical and Electromagnetic Research, State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou, 310058, China.

Illusion devices are usually designed using transformation optics. Here, a new method is proposed to achieve optical illusions without external devices by elaborately manipulating the scattering potential of an object. In contrast to the conventional transformation optics method, which completely replaces one object by the image of another object using complementary\restoring media and a superlens, the method described here is more of a cosmetic operation for an object, which modifies the scattering pattern of the object to mimic another object by exchanging their scattering potentials in two symmetrical areas in the wave vector domain. Read More

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December 2018

A readily usable two-photon FLIM microendoscope.

J Biophotonics 2018 Dec 11:e201800276. Epub 2018 Dec 11.

Université de Limoges, XLIM, Limoges, France.

A two-photon fluorescence lifetime (2P-FLIM) microendoscope, capable of energetic metabolism imaging through the intracellular NADH autofluorescence, at sub-cellular resolution, is demonstrated. It exhibits readily usable characteristics such as convenient endoscope probe diameter (≈ 2 mm), fiber length (> 5 m) and data accumulation rate (16 frames per second (fps), leading to a FLIM refreshing rate of ≈ 0.1 to 1 fps depending on the sample) . Read More

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December 2018

Complex degree of coherence modeling with famous planar curves.

Opt Lett 2018 Dec;43(24):6049-6052

Several planar curves that are well known from mechanics, astronomy, acoustics, etc., and used in other branches of optics, such as caustics and light robotics, are employed for modeling of the recently introduced coherence curves [Opt. Lett. Read More

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December 2018

Enhancement of surface plasmon polariton excitation via feedback-based wavefront shaping.

Opt Lett 2018 Dec;43(24):6021-6024

Surface plasmon polariton (SPP) is an electromagnetic excitation with efficient spatial confinement and high local field intensity at a metal/dielectric interface, which has been widely applied in many fields such as nanophotonics, imaging, biosensing, nonlinear optics, and so on. However, the destructive interference, which arises from wavevector mismatching between the spatial components of incident light and SPP, limits the effective excitation of SPP. Here, we experimentally demonstrate the enhancement of SPP excitation via a feedback-based wavefront shaping method in the Kreschmann configuration. Read More

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December 2018

High-efficiency, linear-polarization-multiplexing metalens for long-wavelength infrared light.

Opt Lett 2018 Dec;43(24):6005-6008

Variable-focus lenses are essential elements of optical systems with extensive applications in microscopy, photography, and optical detection. However, conventional varifocal optical systems obtain a limited tunable capability at the expense of bulk size and slow speed. The metasurfaces are two-dimensional flat structures composed of subwavelength scatterers that exhibit the strong potential for developing ultrathin optics. Read More

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December 2018

Femtosecond fiber Bragg grating fabrication with adaptive optics aberration compensation.

Opt Lett 2018 Dec;43(24):5993-5996

We present fiber Bragg gratings (FBGs) fabricated using adaptive optics aberration compensation for the first time to the best of our knowledge. The FBGs are fabricated with a femtosecond laser by the point-by-point method using an air-based objective lens, removing the requirement for immersion oil or ferrules. We demonstrate a general phase correction strategy that can be used for accurate fabrication at any point in the fiber cross-section. Read More

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December 2018

Spatially encoded polarization-dependent nonlinear optics.

Opt Lett 2018 Dec;43(24):5973-5976

A single fixed optic is combined with the sample translation capabilities inherent to most microscopes to achieve precise polarization-dependent second harmonic generation microscopy measurements of thin tissue sections. Although polarization measurements have enabled detailed structural analysis of collagen, challenges in integrating rotation stages or fast electro-optic/photoelastic modulation have complicated the retrofitting of existing systems for precise polarization analysis. Placing a static microretarder array in the rear conjugate plane resulted in spatially encoded polarization modulation across the field of view. Read More

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December 2018

Volume Law and Quantum Criticality in the Entanglement Entropy of Excited Eigenstates of the Quantum Ising Model.

Phys Rev Lett 2018 Nov;121(22):220602

Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106, USA.

Much has been learned about universal properties of entanglement entropies in ground states of quantum many-body lattice systems. Here we unveil universal properties of the average bipartite entanglement entropy of eigenstates of the paradigmatic quantum Ising model in one dimension. The leading term exhibits a volume-law scaling that we argue is universal for translationally invariant quadratic models. Read More

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November 2018

Controlled Ordering of Topological Charges in an Exciton-Polariton Chain.

Phys Rev Lett 2018 Nov;121(22):225302

Nonlinear Physics Centre, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 2601, Australia.

We demonstrate, experimentally and theoretically, controlled loading of an exciton-polariton vortex chain into a 1D array of trapping potentials. Switching between two types of vortex chains, with topological charges of the same or alternating signs, is achieved by appropriately shaping an off-resonant pump beam that drives the system to the regime of bosonic condensation. In analogy to spin chains, these vortex sequences realize either a "ferromagnetic" or an "antiferromagnetic" order, whereby the role of spin is played by the orbital angular momentum. Read More

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November 2018

Adaptive sliding mode current control with sliding mode disturbance observer for PMSM drives.

ISA Trans 2018 Nov 30. Epub 2018 Nov 30.

Changchun Institute of Optics, Fine Mechanic and Physics, Chinese Academy of Science, Changchun, Jilin 130033, China.

This paper focuses on the current control of a permanent magnet synchronous motor (PMSM) for electric drives with model uncertainties and external disturbances. To improve the performance of the PMSM current loop in terms of the speed of response, tracking accuracy, and robustness, a hybrid control strategy is proposed by combining the adaptive sliding mode control and sliding mode disturbance observer (SMDO). An adaptive law is introduced in the sliding mode current controller to improve the dynamic response speed of the current loop and robustness of the PMSM drive system to the existing parameter variations. Read More

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November 2018

Characterization of Tunable Micro-Lenses with a Versatile Optical Measuring System.

Sensors (Basel) 2018 Dec 12;18(12). Epub 2018 Dec 12.

STMicroelectronics, 20010 Cornaredo (Mi), Italy.

In this work, we present the results of the opto⁻electro⁻mechanical characterization of tunable micro-lenses, Tlens, performed with a single-spot optical measuring system. Tested devices are composed of a transparent soft polymer layer that is deposited on a supporting glass substrate and is covered by a glass membrane with a thin-film piezoelectric actuator on top. Near-infrared optical low-coherence reflectometry is exploited for both static and low-frequency dynamic analyses in the time domain. Read More

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December 2018

Tunable Luminescent A-SiNO Films with High Internal Quantum Efficiency and Fast Radiative Recombination Rates.

Materials (Basel) 2018 Dec 8;11(12). Epub 2018 Dec 8.

College of Science, Jinling Institute of Technology, Nanjing 211169, China.

In this work, we systematically investigated the bonding defects that induced high photoluminescence internal quantum efficiencies (PL IQEs) and very fast radiative recombination processes in amorphous silicon oxynitride (a-SiNO) systems. The luminescent N‒Si‒O bonding-related defect states were checked for the XPS, EPR, and temperature-dependent steady-state PL (TD-SSPL) properties. The PL IQEs were calculated from PL quantum yields through the principle of planar geometry optics, and then confirmed by the TD-SSPL properties. Read More

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December 2018

Effect of Dielectric Distributed Bragg Reflector on Electrical and Optical Properties of GaN-Based Flip-Chip Light-Emitting Diodes.

Micromachines (Basel) 2018 Dec 8;9(12). Epub 2018 Dec 8.

Key Laboratory of Hydraulic Machinery Transients, Ministry of Education, Wuhan University, Wuhan 430072, China.

We demonstrated two types of GaN-based flip-chip light-emitting diodes (FCLEDs) with distributed Bragg reflector (DBR) and without DBR to investigate the effect of dielectric TiO₂/SiO₂ DBR on optical and electrical characteristics of FCLEDs. The reflector consisting of two single TiO₂/SiO₂ DBR stacks optimized for different central wavelengths demonstrates a broader reflectance bandwidth and a less dependence of reflectance on the incident angle of light. As a result, the light output power (LOP) of FCLED with DBR shows 25. Read More

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December 2018

Manufacturing Signatures of Injection Molding and Injection Compression Molding for Micro-Structured Polymer Fresnel Lens Production.

Micromachines (Basel) 2018 Dec 10;9(12). Epub 2018 Dec 10.

Department of Mechanical Engineering, Technical University of Denmark (DTU), 2800 Kgs. Lyngby, Denmark.

Injection compression molding (ICM) provides enhanced optical performances of molded polymer optics in terms of birefringence and transmission of light compared to Injection molding (IM). Nevertheless, ICM requires case-dedicated process optimization to ensure that the required high accuracy geometrical replication is achieved, particularly especially in the case of surface micro-features. In this study, two factorial designs of experiments (DOE) were carried out to investigate the replication capability of IM and ICM on a micro structured Fresnel lens. Read More

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December 2018

Fiber-Optic Magnetic Field Sensing Based on Microfiber Knot Resonator with Magnetic Fluid Cladding.

Sensors (Basel) 2018 Dec 10;18(12). Epub 2018 Dec 10.

College of Science, University of Shanghai for Science and Technology, Shanghai 200093, China.

A kind of all-fiber magnetic field sensing structure is proposed and demonstrated here. The sensing element includes a microfiber knot resonator (MKR) cladded with magnetic fluid (MF). The low-index MgF₂ slab is adopted as the substrate. Read More

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December 2018

A New Disturbance Feedforward Control Method for Electro-Optical Tracking System Line-Of-Sight Stabilization on Moving Platform.

Sensors (Basel) 2018 Dec 10;18(12). Epub 2018 Dec 10.

Institute of Optics and Electronics, Chinese Academy of Science, Chengdu 610209, China.

A feedforward control was proposed based on the decoupling of target movement and disturbance from gyro signals to improve the stabilization precision of line-of-sight (LOS) for an electro-optical tracking system (EOTS) on a moving platform. Signals measured by gyros mounted on gimbal consist of target movement and disturbance. To remove target movement and obtain middle and high frequency disturbance velocity, the gyro signals were filtered by a high pass filter. Read More

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December 2018

Simultaneous Dual-mode Emission and Tunable Multicolor in the Time Domain from Lanthanide-doped Core-shell Microcrystals.

Nanomaterials (Basel) 2018 Dec 7;8(12). Epub 2018 Dec 7.

The Institute of Spectroscopy of the Russian Academy of Sciences, 142190 Moscow, Russia.

The dual-mode emission and multicolor outputs in the time domain from core-shell microcrystals are presented. The core-shell microcrystals, with NaYF₄:Yb/Er as the core and NaYF₄:Ce/Tb/Eu as the shell, were successfully fabricated by employing the hydrothermal method, which confines the activator ions into a separate region and minimizes the effect of surface quenching. The material is capable of both upconversion and downshifting emission, and their multicolor outputs in response to 980 nm near-infrared (NIR) excitation laser and 252 nm, and 395 nm ultraviolet (UV) excitation light have been investigated. Read More

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December 2018

Enhancing charge transfer with foreign molecules through femtosecond laser induced MoS defect sites for photoluminescence control and SERS enhancement.

Nanoscale 2018 Dec 13. Epub 2018 Dec 13.

Department of Electrical and Computer Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0511, USA.

Defect/active site control is crucial for tuning the chemical, optical, and electronic properties of MoS2, which can adjust the performance of MoS2 in application areas such as electronics, optics, catalysis, and molecular sensing. This study presents an effective method of inducing defect/active sites, including micro/nanofractured structures and S atomic vacancies, on monolayer MoS2 flakes by using femtosecond laser pulses, through which physical-chemical adsorption and charge transfer between foreign molecules (O2 or R6G molecules) and MoS2 are enhanced. The enhanced charge transfer between foreign molecules (O2 or R6G) and femtosecond laser-treated MoS2 can enhance the electronic doping effect between them, hence resulting in a photoluminescence photon energy shift (reaching 0. Read More

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December 2018
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Applying Machine Learning Algorithms to Segment High-Cost Patient Populations.

J Gen Intern Med 2018 Dec 12. Epub 2018 Dec 12.

Department of Medical Ethics and Health Policy, University of Pennsylvania Perelman School of Medicine, 1108 Blockley Hall, Philadelphia, PA, 19104, USA.

Background: Efforts to improve the value of care for high-cost patients may benefit from care management strategies targeted at clinically distinct subgroups of patients.

Objective: To evaluate the performance of three different machine learning algorithms for identifying subgroups of high-cost patients.

Design: We applied three different clustering algorithms-connectivity-based clustering using agglomerative hierarchical clustering, centroid-based clustering with the k-medoids algorithm, and density-based clustering with the OPTICS algorithm-to a clinical and administrative dataset. Read More

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December 2018

Self-face and self-body advantages in congenital prosopagnosia: evidence for a common mechanism.

Exp Brain Res 2018 Dec 12. Epub 2018 Dec 12.

NeuroMI-Milan Center for Neuroscience, Milano, Italy.

Prosopagnosia is a disorder leading to difficulties in recognizing faces. However, recent evidence suggests that individuals with congenital prosopagnosia can achieve considerable accuracy when they have to recognize their own faces (self-face advantage). Yet, whether this advantage is face-specific or not is still unclear. Read More

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December 2018

An entanglement-based wavelength-multiplexed quantum communication network.

Nature 2018 12 12;564(7735):225-228. Epub 2018 Dec 12.

Institute for Quantum Optics and Quantum Information-Vienna, Austrian Academy of Sciences, Vienna, Austria.

Quantum key distribution has reached the level of maturity required for deployment in real-world scenarios. It has previously been shown to operate alongside classical communication in the same telecommunication fibre and over long distances in fibre and in free-space links. Despite these advances, the practical applicability of quantum key distribution is curtailed by the fact that most implementations and protocols are limited to two communicating parties. Read More

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December 2018

Vibrio coralliilyticus infection triggers a behavioural response and perturbs nutritional exchange and tissue integrity in a symbiotic coral.

ISME J 2018 Dec 12. Epub 2018 Dec 12.

Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.

Under homoeostatic conditions, the relationship between the coral Pocillopora damicornis and Vibrio coralliilyticus is commensal. An increase in temperature, or in the abundance of V. coralliilyticus, can turn this association pathogenic, causing tissue lysis, expulsion of the corals' symbiotic algae (genus Symbiodinium), and eventually coral death. Read More

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December 2018

Shear wave propagation in viscoelastic media: validation of an approximate forward model.

Phys Med Biol 2018 Dec 3. Epub 2018 Dec 3.

Electrical & Computer Engineering, University of Rochester, Rochester, New York, UNITED STATES.

Many approaches to elastography incorporate shear waves; in some systems these are produced by acoustic radiation force push pulses. Understanding the shape and decay of propagating shear waves in lossy tissues is key to obtaining accurate estimates of tissue properties, and so analytical models have been proposed. In this paper, we reconsider a previous analytical model with the goal of obtaining a computationally straightforward and efficient equation for the propagation of shear waves from a focal push pulse. Read More

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December 2018

Tunable dual emission in Mn2+-doped CsPbX3 (X=Cl, Br) quantum dots for high efficiency white light-emitting diodes.

Nanotechnology 2018 Nov 21. Epub 2018 Nov 21.

State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China, Shanghai, CHINA.

Doping of Mn2+ into semiconductor nanocrystals has been demonstrated to endow them with novel electronic, optical and magnetic functionalities. In this paper, the Mn doped CsPbX3 (X=Br, Cl) quantum dots (QDs) were synthesized at room temperature via a facile strategy by introducing dimethyl sulfoxide (DMSO)-MnBr2/PbX2 composite as precursor. The excitonic emission spectra of the as-obtained Mn doped CsPbX3 QDs can be tuned from 517 nm to 418 nm by adjusting the ratio of PbBr2/PbCl2 precisely, and the luminescence mechanism of the doped QDs is discussed detailedly. Read More

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November 2018

Flexible devices fabricated by plate-to-roll nanoimprint lithography system.

Nanotechnology 2018 Nov 20. Epub 2018 Nov 20.

Department of Optics and Optical Engineering, University of Science and Technology of China, University of Science and Technology of China, No.96, JinZhai Road, Baohe District, Hefei City, Anhui Province, Hefei, Anhui, 230026, CHINA.

Plate-to-roll nanoimprint lithography (P2RNIL) system has been developed to realize high speed, large scale and high resolution nanoimprint process. Imprinted patterns with line width less than 75nm at a speed of 22cm<sup>2</sup>/s on flexible substrate has been achieved. To improve the quality of the patterns imprinted on, we proposed a compliant mechanism which can realize passive alignment and minimize the lateral displacement between the template and substrate. Read More

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November 2018

The role of self-trapped excitons in polaronic recombination processes in lithium niobate.

J Phys Condens Matter 2018 Nov 29. Epub 2018 Nov 29.

Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest, HUNGARY.

Transient absorption and photoluminescence are experimentally investigated in the polaronic reference system lithium niobate, LiNbO<sub>3</sub> (LN), with the aim to refine the microscopic model of small polaron dynamics in materials with strong electron-phonon coupling. As a unique feature, our study is performed by using two different spectroscopic methods, in crystals with dopants enhancing photorefraction or damage resistance, and over a broad temperature range from 15 - 400K. Although being self-consistent for particular experimental conditions, the hitherto used microscopic polaronic models reveal inconsistencies when applied to this larger data set. Read More

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November 2018

Simulation of visual perception and learning with a retinal prosthesis.

J Neural Eng 2018 Nov 20. Epub 2018 Nov 20.

Stanford University, Stanford, California, UNITED STATES.

The nature of artificial vision with a retinal prosthesis, and the degree to which the brain can adapt to the unnatural input from such a device, are poorly understood. Therefore, the development of current and future devices may be aided by theory and simulations that help to infer and understand what prosthesis patients see. A biologically-informed, extensible computational framework is presented here to predict visual perception and the potential effect of learning with a subretinal prosthesis. Read More

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November 2018

Solution Processed Trilayer Structure for High-Performance Perovskite Photodetector.

Nanoscale Res Lett 2018 Dec 6;13(1):399. Epub 2018 Dec 6.

School of Physics & Engineering, Zhengzhou University, Zhengzhou, 450001, China.

Due to their outstanding performance, low cost, ease of fabrication, diverse photonic, and optoelectronic applications, metal halides perovskite have attracted extensive interest in photodetector applications. Currently, devices made by metal oxides, metal sulfides, and 2D materials had achieved good responsivity, but suffered from high dark current, slow response speed, small on-off ratio, and poor stability. Whole performances of these photodetectors are not satisfactory. Read More

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December 2018

Interior X-ray diffraction tomography with low-resolution exterior information.

Phys Med Biol 2018 Dec 12. Epub 2018 Dec 12.

College of Optics and Photonics, University of Central Florida, Orlando, Florida, 32816, UNITED STATES.

X-ray diffraction tomography (XDT) resolves spatially-variant XRD profiles within macroscopic objects, and provides improved material contrast compared to the conventional transmission-based computed tomography (CT). However, due to the small diffraction cross-section, XDT suffers from long imaging acquisition time, which could take tens of hours for a full scan using a table-top X-ray tube. In medical and industrial imaging applications, oftentimes only the XRD measurement within a region-of-interest (ROI) is required, which, together with the demand to reduce imaging time and radiation dose to the sample, motivates the development of interior XDT systems that scan and reconstruct only an internal region within the sample. Read More

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December 2018

Cellular deoxyribonucleic-acid probes of two-photon-excited fluorescent quinolinium-substituted carbazole.

Analyst 2018 Dec 12. Epub 2018 Dec 12.

Key Lab of Functional Inorganic Material Chemistry, Heilongjiang University, no. 74 Xuefu Road, Nangang District, Harbin 150080, PR China. and Key Laboratory of Material Science and Technology for High Power Lasers, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, no. 390 Qinghe Road, Jiading District, Shanghai 201800, PR China.

We report three new types of two-photon-absorption compounds, which contain a carbazole center core linked to two quinolinium units. Their action two-photon absorption cross-sections are 287.13, 267. Read More

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December 2018

Assessing photoreceptor structure in patients with traumatic head injury.

BMJ Open Ophthalmol 2018 24;3(1):e000104. Epub 2018 Nov 24.

Department of Ophthalmology and Visual Sciences, University of WI - Madison, Madison, Wisconsin, USA.

Objective: Previous work using adaptive optics scanning light ophthalmoscopy (AOSLO) imaging has shown photoreceptor disruption to be a common finding in head and ocular trauma patients. Here an expanded trauma population was examined using a novel imaging technique, split-detector AOSLO, to assess remnant cone structure in areas with significant disruption on confocal AOSLO imaging and to follow photoreceptor changes longitudinally.

Methods And Analysis: Eight eyes from seven subjects with head and/or ocular trauma underwent imaging with spectral domain optical coherence tomography, confocal AOSLO and split-detector AOSLO to assess foveal and parafoveal photoreceptor structure. Read More

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November 2018
1 Read

Piezoelectric barium titanate nanostimulators for the treatment of glioblastoma multiforme.

J Colloid Interface Sci 2018 Dec 4;538:449-461. Epub 2018 Dec 4.

Istituto Italiano di Tecnologia, Smart Bio-Interfaces, Viale Rinaldo Piaggio 34, 56025 Pontedera, Italy; Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Corso Duca degli Abruzzi 24, 10129 Torino, Italy. Electronic address:

Major obstacles to the successful treatment of gliolastoma multiforme are mostly related to the acquired resistance to chemotherapy drugs and, after surgery, to the cancer recurrence in correspondence of residual microscopic foci. As innovative anticancer approach, low-intensity electric stimulation represents a physical treatment able to reduce multidrug resistance of cancer and to induce remarkable anti-proliferative effects by interfering with Ca and K homeostasis and by affecting the organization of the mitotic spindles. However, to preserve healthy cells, it is utterly important to direct the electric stimuli only to malignant cells. Read More

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December 2018
1 Read

Efficiency of excitation energy trapping in the green photosynthetic bacterium Chlorobaculum tepidum.

Biochim Biophys Acta Bioenerg 2018 Dec 8;1860(2):147-154. Epub 2018 Dec 8.

Laboratory of Biophysics, Wageningen University, Wageningen, the Netherlands; MicroSpectroscopy Research Facility, Wageningen University, Wageningen, the Netherlands. Electronic address:

During the millions of years of evolution, photosynthetic organisms have adapted to almost all terrestrial and aquatic habitats, although some environments are obviously more suitable for photosynthesis than others. Photosynthetic organisms living in low-light conditions require on the one hand a large light-harvesting apparatus to absorb as many photons as possible. On the other hand, the excitation trapping time scales with the size of the light-harvesting system, and the longer the distance over which the formed excitations have to be transferred, the larger the probability to lose excitations. Read More

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December 2018
1 Read

Rapid Imaging of BCL-2 Family Interactions in Live Cells Using FLIM-FRET.

Methods Mol Biol 2019 ;1877:305-335

Department of Biochemistry, University of Toronto, Toronto, ON, Canada.

The Bcl-2 proteins control cell death via interchanging interactions within the Bcl-2 family. Fluorescence lifetime imaging microscopy (FLIM) is used to detect Förster resonance energy transfer (FRET) between two fluorescent-fusion proteins in live cells. FLIM-FRET has been used to detect specific interactions and their disruption, for Bcl-2 family proteins. Read More

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January 2019

Non-linear Relationship between Blood Pressure and Glaucoma in US Adults.

Am J Hypertens 2018 Dec 8. Epub 2018 Dec 8.

Department of Medicine and Program in Public Health, University of California, Irvine, USA.

Background: Previous studies have reported that vascular disease is associated with glaucoma. However, the relationship between blood pressure (BP) and glaucoma has been inconsistent. We investigated whether there is a non-linear association between BP and glaucoma in an adult population of the United States. Read More

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December 2018
2 Reads

Microwave plasmonic mixer in a transparent fibre-wireless link.

Nat Photonics 2018 Dec 29;12(12):749-753. Epub 2018 Oct 29.

ETH Zurich, Institute of Electromagnetic Fields (IEF), 8092 Zurich, Switzerland.

To cope with the high bandwidth requirements of wireless applications1, carrier frequencies are shifting towards the millimetre-wave and terahertz bands2-5. Conversely, data is normally transported to remote wireless antennas by optical fibres. Therefore, full transparency and flexibility to switch between optical and wireless domains would be desirable6,7. Read More

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December 2018
2 Reads

Backscattering design for a focusing grating coupler with fully etched slots for transverse magnetic modes.

Sci Rep 2018 Dec 10;8(1):17746. Epub 2018 Dec 10.

Institute of Optical and Electronic Materials, Hamburg University of Technology, Eissendorfer Str. 38, Hamburg, 21073, Germany.

Grating couplers are a fundamental building block of integrated optics as they allow light to be coupled from free-space to on-chip components and vice versa. A challenging task in designing any grating coupler is represented by the need for reducing back reflections at the waveguide-grating interface, which introduce additional losses and undesirable interference fringes. Here, we present a design approach for focusing TM grating couplers that minimizes these unwanted reflections by introducing a modified slot that fulfills an anti-reflection condition. Read More

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December 2018

Role of astrocytes, microglia, and tanycytes in brain control of systemic metabolism.

Nat Neurosci 2018 Dec 10. Epub 2018 Dec 10.

Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany.

Astrocytes, microglia, and tanycytes play active roles in the regulation of hypothalamic feeding circuits. These non-neuronal cells are crucial in determining the functional interactions of specific neuronal subpopulations involved in the control of metabolism. Recent advances in biology, optics, genetics, and pharmacology have resulted in the emergence of novel and highly sophisticated approaches for studying hypothalamic neuronal-glial networks. Read More

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December 2018

Effect of wavefunction delocalization on shift current generation.

Authors:
Liang Z Tan

J Phys Condens Matter 2018 Dec 10. Epub 2018 Dec 10.

Molecular Foundry, E O Lawrence Berkeley National Laboratory, 1 Cyclotron Rd M/S 67R3207, Berkeley, California, 94720-8099, UNITED STATES.

We derive upper bounds on the magnitude of shift photocurrent generation of materials in two limiting cases: the flat-band limit of almost-isolated systems such as molecular crystals, and the wide-band limit of one-dimensional or quasi-one-dimensional materials such as ferroelectric polymers or other materials with chain-like motifs. These bounds relate the magnitudes of the shift current bulk photovoltaic effect to materials parameters. In both cases, we find that ratio of electron hopping amplitudes to the band gap plays a vital role in maximizing the amount of nonlinear response. Read More

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December 2018
2.346 Impact Factor

Chromophoric dissolved organic matter influence correction of algal concentration measurements using three-dimensional fluorescence spectra.

Spectrochim Acta A Mol Biomol Spectrosc 2018 Nov 15;210:405-411. Epub 2018 Nov 15.

Key Laboratory of Environmental Optics and technology, Anhui Institute of Optics and fine mechanics, Chinese Academy of Sciences, Hefei 230031, China; Anhui Key Laboratory of environmental optical monitoring technology, Hefei 230031, China.

In view of the adverse effects of CDOM (chromophoric or colored dissolved organic matter) on in vivo algal pigment concentration measurements in natural water bodies, a CDOM influence correction method for algal concentration measurements based on three-dimensional fluorescence spectra is investigated. The three-dimensional fluorescence spectra of five common species of algae belonging to five categories, HA (humic acid), and natural water sampled from the Dongpu reservoir, Hefei were analyzed, and the spectral similarity of endogenous/exogenous CDOM in the algal fluorescence spectra region was compared. HA was selected to represent the CDOM spectrum group. Read More

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November 2018

The diversity of glycosylation of cellobiohydrolase I from Trichoderma reesei determined with mass spectrometry.

Biochem Biophys Res Commun 2018 Dec 7. Epub 2018 Dec 7.

State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, Shandong, China. Electronic address:

Cellulases are glycosylated enzymes that have wide applications in fields like biofuels. It has been widely accepted that glycosylation of cellulases impact their performance. Trichoderma reesei is the most important cellulase-producer and cellobiohydrolase I (CBHI) is the most important cellulase from T. Read More

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December 2018

Whiteness difference thresholds in dentistry.

Dent Mater 2018 Dec 6. Epub 2018 Dec 6.

Post-Graduate Program in Dentistry, Dental School, University of Passo Fundo, Campus I, Passo Fundo, RS, Brazil.

Objective: To determine the visual whiteness thresholds for esthetic dentistry using the whiteness index for dentistry based on CIELAB color space (WI).

Methods: A total of 60 observers (Dentists and Laypersons; n=30) from three research sites participated in the study. A psychophysical experiment based on visual assessments of simulated images of teeth on a calibrated display was performed. Read More

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December 2018