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Lucas S A Pereira, Sabrina A Camacho, Antonio A Malfatti-Gasperini, Karen Jochelavicius, Thatyane M Nobre, Osvaldo N Oliveira, Pedro H B Aoki
Photodynamic therapy (PDT) efficiency depends on many factors including the incorporation of the photosensitizer (PS) in cell membranes and possible lipid hydroperoxidation. In this study, we show that hydroperoxidation may be photoinduced when eosin Y is incorporated into Langmuir monolayers that serve as cell membrane models. This occurs for Langmuir monolayers of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), which have unsaturation in their hydrophobic chains...
August 6, 2018: Colloids and Surfaces. B, Biointerfaces
Nicholas H Julian, Tian T Li, Robert E Rudd, Jaime Marian
Atomic configurations of glassy or amorphous materials containing medium-range order (MRO) may be identified by comparing fluctuation transmission electron microscopy (FTEM) measurements to FTEM simulations obtained using model configurations. Candidate model sizes have traditionally been much thinner than the samples measured experimentally, and publicly available FTEM simulation software has until now omitted microscope parameters, dynamical scattering, and the phase of the diffracted electron wave. We introduce MS-STEM-FEM, an open-source software package for simulating FTEM experiments using established multi-slice TEM simulation techniques to emulate experiment more closely by incorporating microscope parameters and simulating electron scattering and propagation as a complex valued wave...
August 2, 2018: Ultramicroscopy
M Suriya, Chagam Koteswara Reddy, Sundaramoorthy Haripriya, N Harsha
In this study, Amorphophallus paeoniifolius (elephant foot yam) starch nanoparticles (SNPs) were produced using a native facile and green procedure integrated with debranching and recrystallization. SNPs were produced through debranching with pullulanase followed by 12- and 24-h retrogradation time. Transmission electron microscopy, dynamic light scattering, infrared spectroscopy, differential scanning colorimetry, and x-ray diffraction were utilized to illustrate the in-vitro digestibility, molecular structure, morphology, and behavior changes of SNPs...
August 13, 2018: International Journal of Biological Macromolecules
Paweł Woźniak, Israel De Leon, Katja Höflich, Caspar Haverkamp, Silke Christiansen, Gerd Leuchs, Peter Banzer
We investigate the chiroptical response of a single plasmonic nanohelix interacting with a weakly focused circularly polarized Gaussian beam. The optical scattering at the fundamental resonance is characterized experimentally and numerically. The angularly resolved scattering of the excited nanohelix is verified experimentally and it validates the numerical results. We employ a multipole decomposition analysis to study the fundamental and first higher-order resonance of the nanohelix, explaining their chiral properties in terms of the formation of chiral dipoles...
July 23, 2018: Optics Express
Qiu-Rong Yan, Hui Wang, Cheng-Long Yuan, Bing Li, Yu-Hao Wang
We demonstrate a single photon compressive imaging system with the image plane up to the entire digital micro-mirror device (DMD) work area. A parallel light source is designed to reduce the influence of light scattering on imaging resolution and a photon counting photomultiplier tube (PMT) with a large photosensitive area is used to effectively collect light reflected from the full screen of DMD. A control and counting circuit, based on Field-Programmable Gate Array (FPGA), is developed to load binary random matrix into the DMD controller for each measurement, and to count single-photon pulse output from PMT simultaneously...
July 23, 2018: Optics Express
Luke Maidment, Peter G Schunemann, Rhea J Clewes, Martin D Bowditch, Christopher R Howle, Derryck T Reid
Infrared spectroscopy in the spectral fingerprint region from 6.5 to 20 µm has been applied for decades to identify vapor- and condensed-phase chemicals with high confidence. By employing a unique broadband laser operating from 7.2- to 11.5-µm we show that, in this region, wavelength-dependent Mie-scattering effects substantially modulate the underlying chemical absorption signature, undermining the ability of conventional infrared absorption spectroscopy to identify aerosolized liquids and solids. In the aerosol studied, Mie theory predicts that the positions of spectroscopic features will blue-shift by up to 200 nm, and this behavior is confirmed by experiment, illustrating the critical importance of considering Mie contributions to aerosol spectroscopy in the mid infrared...
July 23, 2018: Optics Express
Nicola Coluccelli, Edoardo Vicentini, Alessio Gambetta, Christopher R Howle, Kenneth Mcewan, Paolo Laporta, Gianluca Galzerano
We demonstrate a Fourier transform (FT) coherent anti-Stokes Raman scattering (CARS) spectroscopy system based on fiber technology with ultra-broad spectral coverage and high-sensitivity. A femtosecond ytterbium fiber oscillator is amplified and spectrally broadened in a photonic crystal fiber to synthesize pulses with energy of 14 nJ at 1040 nm, that are compressed to durations below 20 fs. The resulting pulse train is coupled to a FT-CARS interferometer enabling measurement of high-quality CARS spectra with Raman shifts of ~3000 cm-1 and signal to noise ratio up to 240 and 690 with acetonitrile and polystyrene samples, respectively, for observation times of 160 µs; a detection limit of one part per thousand is demonstrated with a cyanide/water solution...
July 23, 2018: Optics Express
Hendrik Spahr, Clara Pfäffle, Peter Koch, Helge Sudkamp, Gereon Hüttmann, Dierck Hillmann
Doppler optical coherence tomography (OCT) quantifies axial motion with high precision, whereas lateral motion cannot be detected by a mere evaluation of phase changes. This problem was solved by the introduction of three-beam Doppler OCT, which, however, entails a high experimental effort. Here, we present the numerical analogue to this experimental approach. Phase-stable complex-valued OCT datasets, recorded with full-field swept-source OCT, are filtered in the Fourier domain to limit imaging to different computational subapertures...
July 23, 2018: Optics Express
D V Tsarev, S M Arakelian, You-Lin Chuang, Ray-Kuang Lee, A P Alodjants
Considering matter wave bright solitons from weakly coupled Bose-Einstein condensates trapped in a double-well potential, we study the formation of macroscopic non-classical states, including Schrödinger-cat superposition state and maximally path entangled N00N-state. We examine these macroscopic states by Mach-Zehnder interferometer in the context of parity measurements, which has been done to obtain Heisenberg limit accuracy for linear phase shift measurement. We reveal that the ratio of two-body scattering length to intra-well hopping parameter can be measured with the scaling beyond this limit by using nonlinear phase shift with interacting quantum solitons...
July 23, 2018: Optics Express
Bernd Kästner, Franko Schmähling, Andrea Hornemann, Georg Ulrich, Arne Hoehl, Mattias Kruskopf, Klaus Pierz, Markus B Raschke, Gerd Wübbeler, Clemens Elster
Infrared scattering scanning near-field optical microscopy (IR s-SNOM) provides for spectroscopic imaging with nanometer spatial resolution, yet full spatio-spectral imaging is constrained by long measurement times. Here, we demonstrate the application of compressed sensing algorithms to achieve hyperspectral FTIR-based nano-imaging at an order of magnitude faster imaging speed to achieve the same spectral content compared to conventional approaches. At the example of the spectroscopy of a single vibrational resonance, we discuss the relationship of prior knowledge of sparseness of the employed Fourier base functions and sub-sampling...
July 9, 2018: Optics Express
Nitin Gupta, Anuj Dhawan
In this paper, we present bridged-bowtie nanohole arrays and cross bridged-bowtie nanohole arrays in a gold thin film as surface enhanced Raman scattering (SERS) substrates. These SERS substrates not only exhibit large electromagnetic enhancement of SERS but also have the SERS enhancement spread over a much larger area than what could be present in SERS substrates consisting of nanopillar arrays or nanopillar plasmonic nanoantennas. Numerical simulations based on the finite difference time domain (FDTD) method are employed to determine electric field enhancement factors (EFs) and therefore the electromagnetic SERS enhancement factor for these SERS substrates...
July 9, 2018: Optics Express
Patrick R Whelan, Deping Huang, David Mackenzie, Sara A Messina, Zhancheng Li, Xin Li, Yunqing Li, Timothy J Booth, Peter U Jepsen, Haofei Shi, Peter Bøggild
Fast inline characterization of the electrical properties of graphene on polymeric substrates is an essential requirement for quality control in industrial graphene production. Here we show that it is possible to measure the sheet conductivity of graphene on polymer films by terahertz time-domain spectroscopy (THz-TDS) when all internally reflected echoes in the substrate are taken into consideration. The conductivity measured by THz-TDS is comparable to values obtained from four point probe measurements. THz-TDS maps of 25x30 cm2 area graphene films were recorded and the DC conductivity and carrier scattering time were extracted from the measurements...
July 9, 2018: Optics Express
Maria C Giordano, Stefan Mastel, Clemens Liewald, Lorenzo L Columbo, Massimo Brambilla, Leonardo Viti, Antonio Politano, Kai Zhang, Lianhe Li, A Giles Davies, Edmund H Linfield, Rainer Hillenbrand, Fritz Keilmann, Gaetano Scamarcio, Miriam S Vitiello
At terahertz (THz) frequencies, scattering-type scanning near-field optical microscopy (s-SNOM) based on continuous wave sources mostly relies on cryogenic and bulky detectors, which represents a major constraint for its practical application. Here, we devise a THz s-SNOM system that provides both amplitude and phase contrast and achieves nanoscale (60-70nm) in-plane spatial resolution. It features a quantum cascade laser that simultaneously emits THz frequency light and senses the backscattered optical field through a voltage modulation induced inherently through the self-mixing technique...
July 9, 2018: Optics Express
Matthew N Ashner, William A Tisdale
Time-resolved femtosecond stimulated Raman spectroscopy (FSRS) is a powerful tool for investigating ultrafast structural and vibrational dynamics in light absorbing systems. However, the technique generally requires exposing a sample to high laser pulse fluences and long acquisition times to achieve adequate signal-to-noise ratios. Here, we describe a time-resolved FSRS instrument built around a Yb ultrafast amplifier operating at 200 kHz, and address some of the unique challenges that arise at high repetition-rates...
July 9, 2018: Optics Express
Ishwor Koirala, Sang-Shin Lee, Duk-Yong Choi
Transmissive subtractive color filters are proposed and demonstrated that take advantage of an all-dielectric metasurface based on a lattice of TiO2 nanopillars (NPs), rendering a high transmission efficiency that exceeds 90%. TiO2 NP elements have been created that exhibit a high aspect ratio. Specifically, a series of lithographic processes are conducted to form a narrow and deep hole in the photoresist, which is accompanied by atomic layer deposition of TiO2 . A broad palette of vivid colors encompassing the visible band has been obtained by adjusting the NP diameter for a constant duty ratio of 0...
July 9, 2018: Optics Express
James F Pankow, Kilsun Kim, Wentai Luo, Kevin J McWhirter
For an electronic cigarette (e-cigarette) aerosol with known total particulate matter concentration (TPM, μg/m3 ), predictions of the fractions of some compound i in the gas and particle phases ( fg, i and fp, i ) at equilibrium can be made based on Kp, i (m3 /μg), the compound-dependent gas/particle partitioning equilibrium constant. fg, i and fp, i affect the modes and locations of deposition in the respiratory tract. Kp, i depends inversely on: 1) the pure-compound liquid vapor pressure ( po L, i ); 2) mole-fraction activity coefficient (ζ i ) in the absorbing liquid; and 3) mean molecular weight of the absorbing liquid (MW)...
August 16, 2018: Chemical Research in Toxicology
Xiuling Xu, Fan Hu, Qi Shuai
A facile reversed-phase microemulsion method was used to synthesize shell-core nanospheres of SiO2 @RCs (SiO2 -encapsuled rare-earth metal complexes). β-d-Galactose was then grafted onto the surfaces of the nanospheres through the copper(I)-catalyzed azide-alkyne cycloaddition click reaction for targeted delivery. The chemical characteristics and surface profiles of the nanocarriers were investigated by Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy, and scanning electron microscopy...
August 16, 2018: Inorganic Chemistry
Ting-Ting Zhai, Dekai Ye, Yi Shi, Qian-Wen Zhang, Xiang Qin, Chen Wang, Xing-Hua Xia
We demonstrate a core-satellite plasmonic nanoprobe assembled via metal ion-dependent DNA-cleaving DNAzyme linker for imaging intercellular metal ion based on plasmon coupling effect at a single particle level. As metal ions are present in the system, the DNAzyme linker will be cleaved, and thus, disassembly of the core-satellite nanoprobes occurs, which results in distinct blue shift of the scattering spectra of Au core-satellite probes and naked color change of the scattering light. This change in scattering spectra has been supported by theoretical simulations...
August 16, 2018: ACS Applied Materials & Interfaces
Chung-Wei Kung, Ana E Platero-Prats, Riki J Drout, Junmo Kang, Timothy C Wang, Cornelius O Audu, Mark C Hersam, Karena W Chapman, Omar K Farha, Joseph T Hupp
A representative mesoporous metal-organic-framework (MOF) material, NU-1000, has been rendered electronically conductive via a robust inorganic approach that permits retention of MOF crystallinity and porosity. The approach is based on condensed-phase grafting of molecular tin species onto the MOF nodes via irreversible reaction with hydroxyl and aqua ligands presented at the node surface, a self-limiting process termed Solvothermal Installation (of metal ions) in MOFs (SIM, a solution-phase analog of atomic layer deposition in MOFs)...
August 16, 2018: ACS Applied Materials & Interfaces
Juqiang Han, Shuai Wang, Thomas Ngai Yeung Kwong, Jian Liu
RATIONALE: Dermatomyositis is an idiopathic inflammatory myopathy with specific cutaneous manifestations, which is closely associated with malignancy. However, the exact mechanism remains elusive. Even less is known about dermatomyositis with hepatocellular carcinoma (HCC). PATIENT CONCERNS: We reported a case of dermatomyositis with hepatitis B virus (HBV) infection. He incidentally found his lower limbs little weakness accompanied with his wrist erythema. He was found HBsAg positive for forty years with slightly positive of α-fetal protein (AFP)...
August 2018: Medicine (Baltimore)
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