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https://www.readbyqxmd.com/read/28723583/label-free-high-resolution-3-d-imaging-of-gold-nanoparticles-inside-live-cells-using-optical-diffraction-tomography
#1
Doyeon Kim, Nuri Oh, Kyoohyun Kim, SangYun Lee, Chan-Gi Pack, Ji-Ho Park, YongKeun Park
Delivery of gold nanoparticles (GNPs) into live cells has high potentials, ranging from molecular-specific imaging, photodiagnostics, to photothermal therapy. However, studying the long-term dynamics of cells with GNPs using conventional fluorescence techniques suffers from phototoxicity and photobleaching. Here, we present a method for 3-D imaging of GNPs inside live cells exploiting refractive index (RI) as imaging contrast. Employing optical diffraction tomography, 3-D RI tomograms of live cells with GNPs are precisely measured for an extended period with sub-micrometer resolution...
July 16, 2017: Methods: a Companion to Methods in Enzymology
https://www.readbyqxmd.com/read/28723204/crossed-surface-relief-gratings-as-nanoplasmonic-biosensors
#2
Srijit Nair, Carlos Escobedo, Ribal Georges Sabat
We present an original, low-cost nanoplasmonic (bio)sensor based on crossed surface relief gratings (CSRGs) generated from orthogonally superimposed surface relief gratings (SRGs) on gold-coated azo-glass substrate. This surface plasmon resonance (SPR)-based sensing approach is unique, since the light transmitted through a CSRG is zero except in the narrow bandwidth where the SPR conversion occurs, enabling quantitative monitoring of only the plasmonic signal from biomolecular interactions in real time. We validated the individual SRG plasmonic signature of CSRGs by observing their respective SPR excitation peaks, and tested them to detect both bulk and near-surface refractive index (RI) changes...
March 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723169/nanoantenna-enhanced-infrared-spectroscopic-chemical-imaging
#3
Lucca Kühner, Mario Hentschel, Ute Zschieschang, Hagen Klauk, Jochen Vogt, Christian Huck, Harald Giessen, Frank Neubrech
Spectroscopic infrared chemical imaging is ideally suited for label-free and spatially resolved characterization of molecular species, but often suffers from low infrared absorption cross sections. Here, we overcome this limitation by utilizing confined electromagnetic near-fields of resonantly excited plasmonic nanoantennas, which enhance the molecular absorption by orders of magnitude. In the experiments, we evaporate microstructured chemical patterns of C60 and pentacene with nanometer thickness on top of homogeneous arrays of tailored nanoantennas...
May 26, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28723144/inflection-point-of-the-localized-surface-plasmon-resonance-peak-a-general-method-to-improve-the-sensitivity
#4
Peng Chen, Nhung Thi Tran, Xinglin Wen, Qihua Xiong, Bo Liedberg
The shift of the localized surface plasmon resonance (LSPR) spectrum is widely used in bio- and chemical sensing. Traditionally, the shift is monitored at the peak maximum of the extinction spectrum. We demonstrate that the inflection point at the long wavelength side of the peak maximum shows better refractive index sensitivity than the peak maximum. A consistent improvement in bulk refractive index sensitivity of 18-55% is observed for six different nanoparticles such as spherical particles of different sizes, nanostar and nanorods with different aspect ratios...
February 24, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28722436/potential-to-detect-hydrogen-concentration-gradients-with-palladium-infused-mesoporous-titania-on-d-shaped-optical-fiber
#5
Zsolt L Poole, Paul R Ohodnicki, Aidong Yan, Yuankun Lin, Kevin P Chen
A distributed sensing capable high temperature D-shaped optical fiber modified with a palladium nanoparticle sensitized mesoporous (∼5 nm) TiO2 film, is demonstrated. The refractive index of the TiO2 film was reduced using block copolymer templating in order to realize a mesoporous matrix, accommodating integration with optical fiber. The constructed sensor was analyzed by performing direct transmission loss measurements, and by analyzing the behavior of an integrated fiber Bragg grating. The inscribed grating should reveal whether the refractive index of the composite film experiences changes upon exposure to hydrogen...
January 27, 2017: ACS Sensors
https://www.readbyqxmd.com/read/28722394/direct-electrospray-printing-of-gradient-refractive-index-chalcogenide-glass-films
#6
Spencer Novak, Pao Tai Lin, Cheng Li, Chatdanai Lumdee, Juejun Hu, Anuradha Murthy Agarwal, Pieter G Kik, Weiwei Deng, Kathleen Richardson
A spatially varying effective refractive index gradient using chalcogenide glass layers is printed on a silicon wafer using an optimized electrospray (ES) deposition process. Using solution-derived glass precursors, infrared transparent Ge23Sb7S70 and As40S60 glass films of programmed thickness are fabricated to yield a bilayer structure resulting in an effective gradient refractive index (GRIN) film. Optical and compositional analysis tools confirm the optical and physical nature of the gradient in the resulting high optical quality films, demonstrating the power of direct printing of multi-material structures compatible with planar photonic fabrication protocols...
July 19, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28722050/database-and-new-models-based-on-a-group-contribution-method-to-predict-the-refractive-index-of-ionic-liquids
#7
Xinxin Wang, Xingmei Lu, Qing Zhou, Yongsheng Zhao, Xiaoqian Li, Suojiang Zhang
Refractive index is one of the important physical properties, which is widely used in separation and purification. In this study, the refractive index data of ILs were collected to establish a comprehensive database, which included about 2138 pieces of data from 1996 to 2014. The Group Contribution-Artificial Neural Network (GC-ANN) model and Group Contribution (GC) method were employed to predict the refractive index of ILs at different temperatures from 283.15 K to 368.15 K. Average absolute relative deviations (AARD) of the GC-ANN model and the GC method were 0...
July 19, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28721935/prevalence-of-eye-disease-and-visual-impairment-in-%C3%A3-le-de-la-gonave-ha%C3%A3-ti
#8
B Tousignant, J Brûlé
Epidemiological data describing the prevalence of blindness and visual impairment in Haiti are sparse. The Haitian National Committee for the Prevention of Blindness (CNPC) estimates the prevalence of blindness at 1 %. Other regional data estimate moderate and severe visual impairment at 5% and 22%, respectively. IRIS Mundial (IM) is a non-governmental organization collaborating with the CNPC to develop eye care infrastructure in Haiti. To estimate the prevalence and causes of blindness and visual impairment on the Haitian island of Gonâve, to assist in planning of relevant eye care infrastructure...
July 19, 2017: Médecine et Santé Tropicales
https://www.readbyqxmd.com/read/28721695/myopes-have-significantly-higher-serum-melatonin-concentrations-than-non-myopes
#9
Stephanie Kearney, Lisa O'Donoghue, Kirsty L Pourshahidi, Diego Cobice, Kathryn J Saunders
PURPOSE: Experimental animal models of myopia demonstrate that higher melatonin (Mel) and lower dopamine (DA) concentrations actively promote axial elongation. This study explored the association between myopia and serum concentrations of DA and Mel in humans. METHODS: Morning serum concentrations of DA and Mel were measured by solid phase extraction-liquid chromatography-tandem mass spectrometry from 54 participants (age 19.1 ± 0.81 years) in September/October 2014 (phase 1) and March/April 2016 (phase 2)...
July 18, 2017: Ophthalmic & Physiological Optics: the Journal of the British College of Ophthalmic Opticians (Optometrists)
https://www.readbyqxmd.com/read/28721008/effect-of-age-sex-and-refractive-errors-on-central-corneal-thickness-measured-by-oculus-pentacam-%C3%A2
#10
Nauman Hashmani, Sharif Hashmani, Azfar N Hanfi, Misbah Ayub, Choudhry M Saad, Hina Rajani, Marium G Muhammad, Misbahul Aziz
BACKGROUND: Central corneal thickness (CCT) can be used to assess the corneal physiological condition as well as the pathological changes associated with ocular diseases. It has an influence on the measurement of intraocular pressure and is being used as a screening tool for refractive surgery candidates. The aim of this study was to determine the median CCT among normal Pakistani population and to correlate CCT with age, sex, and refractive errors. METHODS: We conducted a retrospective analysis of 5,171 healthy eyes in 2,598 patients who came to Hashmanis Hospital, Karachi, Pakistan...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28721004/epithelium-on-photorefractive-intrastromal-cross-linking-pixl-for-reduction-of-low-myopia
#11
Wee Kiak Lim, Zhi Da Soh, Harold Kah Yen Choi, Julian Thiam Siew Theng
PURPOSE: To report the 9-12-month outcomes of a novel procedure for reduction of low myopia through epithelium-on photorefractive intrastromal cross-linking (PiXL) with customized control of topographic distribution of ultraviolet (UV)-fluence. METHOD: Myopic patients with normal (non-ectatic) corneas underwent the PiXL procedure for reduction of low myopia. PiXL treatments were delivered through selective application of UVA light based on the refractive error of each patient...
2017: Clinical Ophthalmology
https://www.readbyqxmd.com/read/28719538/misight-assessment-study-spain-a-comparison-of-vision-related-quality-of-life-measures-between-misight-contact-lenses-and-single-vision-spectacles
#12
Alicia Ruiz Pomeda, Belén Pérez-Sánchez, Maria Del Pilar Cañadas Suárez, Francisco Luis Prieto Garrido, Ramón Gutiérrez-Ortega, César Villa-Collar
OBJECTIVES: Recent research has shown that concentric contact lenses (CLs) can be a way to control the progression of myopia. The purpose of the current study was to compare vision-related quality-of-life measures in children wearing distance single-vision (SV) spectacles versus MiSight CLs, a specific concentric design for myopia control. METHODS: Subjects aged 8 to 12 with myopia from -0.75 to -4.00 diopters (D) of sphere and astigmatism less than 1.00 D of cylinder were allocated to the lenses study group (MiSight) or control group (SV)...
July 14, 2017: Eye & Contact Lens
https://www.readbyqxmd.com/read/28719417/anterior-chamber-angle-and-trabecular-meshwork-measurements-made-by-fourier-domain-optical-coherence-tomography-in-healthy-white-children
#13
José I Fernández-Vigo, Lucía De-Pablo-Gómez-de-Liaño, Cristina Fernández-Vigo, Gabriel Arcos-Villegas, Cristina Fernández-Pérez, Julián García-Feijóo, José Á Fernández-Vigo
PURPOSE: To obtain anterior chamber angle and trabecular meshwork (TM) measurements by Fourier-domain optical coherence tomography (FD-OCT) in a population of healthy white children. MATERIALS AND METHODS: This was a cross-sectional study examining 409 right eyes of 409 children. Trabecular-iris angle (TIA) and TM length and area were measured by FD-OCT (RTVue 100) in the nasal and temporal quadrants to analyze correlations between angle or TM measurements and age, sex, and refractive error...
July 17, 2017: Journal of Glaucoma
https://www.readbyqxmd.com/read/28719095/a-new-perspective-on-transparent-wood-lignin-retaining-transparent-wood
#14
Yuanyuan Li, Qiliang Fu, Ramiro Rojas, Min Yan, Martin Lawoko, Lars Berglund
Optically transparent wood, combining optical and mechanical performance, is an emerging new material for light transmitting structures in buildings with the aim of reducing energy consumption. One of the main obstacles for transparent wood fabrication is delignification, where around 30 wt% of wood tissue is removed to reduce light absorption and refractive index mismatch. This step is time consuming and not environmentally benign. Meanwhile, lignin removal weakens the wood structure, limiting the fabrication of large structure...
July 18, 2017: ChemSusChem
https://www.readbyqxmd.com/read/28718904/autologous-serum-eye-drops-and-enhanced-epithelial-healing-time-after-photorefractive-keratectomy
#15
Hanife Tuba Akcam, Metin Unlu, Emine Esra Karaca, Hulya Yazici, Bahri Aydin, Ahmet Murad Hondur
BACKGROUND: The aim of the study is to test whether use of autologous serum eye-drops can provide earlier epithelial healing following the application of photorefractive keratectomy. METHOD: Sixty patients (60 eyes) underwent photorefractive keratectomy for myopia. Thirty eyes received autologous serum drops (Study group) while 30 eyes received conventional artificial tears (Control group) after photorefractive keratectomy. An 8 mm epithelial opening was prepared with the application of 18 per cent alcohol for 20 seconds...
July 18, 2017: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
https://www.readbyqxmd.com/read/28717973/design-and-development-of-repaglinide-microemulsion-gel-for-transdermal-delivery
#16
Ujwala A Shinde, Sheela H Modani, Kavita H Singh
Microemulsion formulation of repaglinide, a BCS class II hypoglycemic agent with limited oral bioavailability, was developed considering its solubility in various oils, surfactants, and cosurfactants. The pseudo-ternary phase diagrams for microemulsion regions were constructed by water titration method at K m 1:1 and characterized for optical birefringence, percentage transmittance, pH, refractive index, globule size, zeta potential, viscosity, drug content, and thermodynamic stability. To enhance the drug permeation and residence time, the optimized microemulsions having mean globule size of 36...
July 17, 2017: AAPS PharmSciTech
https://www.readbyqxmd.com/read/28717577/temporal-multiplexing-to-simulate-multifocal-intraocular-lenses-theoretical-considerations
#17
Vyas Akondi, Carlos Dorronsoro, Enrique Gambra, Susana Marcos
Fast tunable lenses allow an effective design of a portable simultaneous vision simulator (SimVis) of multifocal corrections. A novel method of evaluating the temporal profile of a tunable lens in simulating different multifocal intraocular lenses (M-IOLs) is presented. The proposed method involves the characteristic fitting of the through-focus (TF) optical quality of the multifocal component of a given M-IOL to a linear combination of TF optical quality of monofocal lenses viable with a tunable lens. Three different types of M-IOL designs are tested, namely: segmented refractive, diffractive and refractive extended depth of focus...
July 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/28717186/overstepping-the-upper-refractive-index-limit-to-form-ultra-narrow-photonic-nanojets
#18
Guoqiang Gu, Jun Song, Hongda Liang, Mengjie Zhao, Yue Chen, Junle Qu
In general, photonic nanojets (PNJs) occur only when the refractive index (Ri) difference between the microparticle and background media is less than 2. The minimum full width at half-maximum (FWHM) of the PNJ is ~130 nm (approximately one-third of the illumination wavelength λ = 400 nm) formed within the evanescent field region. This paper proposes and studies a method to overstep the Ri upper bound and generate ultra-narrow PNJs. Finite element method based numerical investigations and ray-optics theoretical analyses have realized ultra-narrow PNJs with FWHM as small as 114...
July 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28716601/changes-in-refractive-status-in-an-elderly-chinese-population-in-a-7-year-follow-up-the-shihpai-eye-study
#19
Tung-Mei Kuang, Su-Ying Tsai, Catherine Jiu-Ling Liu, Yu-Chieh Ko, Shui-Mei Lee, Pesus Chou
BACKGROUND: Refractive error is the major cause of moderate and severe visual impairment. Visual impairment limits people's ability to perform daily tasks and affects their quality of life. Longitudinal data on the refractive status of the elderly was available only for whites and Africans. The purpose of this study was to report the 7-year incidence of myopia, hyperopia and refractive error change as well as their associated risk factors in a metropolitan elderly Chinese population. METHODS: The Shihpai Eye Study 2006 included 460/824 (55...
July 14, 2017: Journal of the Chinese Medical Association: JCMA
https://www.readbyqxmd.com/read/28716114/visumax-femtolasik-versus-moria-m2-microkeratome-in-mild-to-moderate-myopia-efficacy-safety-predictability-aberrometric-changes-and-flap-thickness-predictability
#20
Magda A Torky, Yousif A Al Zafiri, Abeer M Khattab, Rania K Farag, Eman A Awad
INTRODUCTION: This is an interventional prospective clinical study which was conducted to evaluate the efficacy, safety, predictability, ocular aberrations, and flap thickness predictability of Visumax femtosecond laser (FSL) compared to Moria M2 microkeratome (MK) in mild to moderate myopia. METHODS: This study included 60 eyes who were divided into two groups. Thirty eyes in group (I) in which the flap was created with Visumax FSL, while in group II (30 eyes) the Moria M2 MK was used...
July 17, 2017: BMC Ophthalmology
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