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https://www.readbyqxmd.com/read/29315870/chiroptical-properties-of-2-2-bioxirane
#1
N Daugey, N De Rycke, T Brotin, T Buffeteau
The two enantiomers of 2,2'-bioxirane were synthesized, and their chiroptical properties were thoroughly investigated in various solvents by polarimetry, vibrational circular dichroism (VCD), and Raman optical activity (ROA). Density functional theory (DFT) calculations at the B3LYP/aug-cc-pVTZ level revealed the presence of three conformers (G+ , G- , and cis) with Gibbs populations of 51, 44, and 5% for the isolated molecule, respectively. The population ratios of the two main conformers were modified for solvents exhibiting higher dielectric constants (G- form decreases whereas G+ form increases)...
January 9, 2018: Chirality
https://www.readbyqxmd.com/read/29291065/why-do-horseflies-need-polarization-vision-for-host-detection-polarization-helps-tabanid-flies-to-select-sunlit-dark-host-animals-from-the-dark-patches-of-the-visual-environment
#2
Gábor Horváth, Tamás Szörényi, Ádám Pereszlényi, Balázs Gerics, Ramón Hegedüs, András Barta, Susanne Åkesson
Horseflies (Tabanidae) are polarotactic, being attracted to linearly polarized light when searching for water or host animals. Although it is well known that horseflies prefer sunlit dark and strongly polarizing hosts, the reason for this preference is unknown. According to our hypothesis, horseflies use their polarization sensitivity to look for targets with higher degrees of polarization in their optical environment, which as a result facilitates detection of sunlit dark host animals. In this work, we tested this hypothesis...
November 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/29289238/noise-characterization-for-resonantly-enhanced-polarimetric-vacuum-magnetic-birefringence-experiments
#3
M T Hartman, A Rivère, R Battesti, C Rizzo
In this work we present data characterizing the sensitivity of the Biréfringence Magnetique du Vide (BMV) instrument. BMV is an experiment attempting to measure vacuum magnetic birefringence (VMB) via the measurement of an ellipticity induced in a linearly polarized laser field propagating through a birefringent region of vacuum in the presence of an external magnetic field. Correlated measurements of laser noise alongside the measurement in the main detection channel allow us to separate measured sensing noise from the inherent birefringence noise of the apparatus...
December 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29248662/coronary-plaque-microstructure-and-composition-modify-optical-polarization-a-new-endogenous-contrast-mechanism-for-optical-frequency-domain-imaging
#4
Martin Villiger, Kenichiro Otsuka, Antonios Karanasos, Pallavi Doradla, Jian Ren, Norman Lippok, Milen Shishkov, Joost Daemen, Roberto Diletti, Robert-Jan van Geuns, Felix Zijlstra, Gijs van Soest, Peter Libby, Evelyn Regar, Seemantini K Nadkarni, Brett E Bouma
OBJECTIVES: This study aimed to evaluate whether polarimetry, performed using a modified optical frequency domain imaging (OFDI) system, can improve the assessment of histological features relevant to characterizing human coronary atherosclerosis. BACKGROUND: The microscopic structure and organization of the arterial wall influence the polarization of the infrared light used by OFDI. Modification of the OFDI apparatus, along with recently developed image reconstruction methods, permits polarimetric measurements simultaneously with conventional OFDI cross-sectional imaging through standard intravascular imaging catheters...
December 9, 2017: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/29240124/mueller-matrix-polarimetry-on-plasma-sprayed-thermal-barrier-coatings-for-porosity-measurement
#5
David A Luo, Enrique T Barraza, Michael W Kudenov
Yttria-stabilized zirconia (YSZ) is the most widely used material for thermal plasma sprayed thermal barrier coatings (TBCs) used to protect gas turbine engine parts in demanding operation environments. The superior material properties of YSZ coatings are related to their internal porosity level. By quantifying the porosity level, tighter control on the spraying process can be achieved to produce reliable coatings. Currently, destructive measurement methods are widely used to measure the porosity level. In this paper, we describe a novel nondestructive approach that is applicable to classify the porosity level of plasma sprayed YSZ TBCs via Mueller matrix polarimetry...
December 10, 2017: Applied Optics
https://www.readbyqxmd.com/read/29206182/phase-sensitive-surface-plasmon-resonance-sensors-recent-progress-and-future-prospects
#6
REVIEW
Shijie Deng, Peng Wang, Xinglong Yu
Surface plasmon resonance (SPR) is an optical sensing technique that is capable of performing real-time, label-free and high-sensitivity monitoring of molecular interactions. SPR biosensors can be divided according to their operating principles into angle-, wavelength-, intensity- and phase-interrogated devices. With their complex optical configurations, phase-interrogated SPR sensors generally provide higher sensitivity and throughput, and have thus recently emerged as prominent biosensing devices. To date, several methods have been developed for SPR phase interrogation, including heterodyne detection, polarimetry, shear interferometry, spatial phase modulation interferometry and temporal phase modulation interferometry...
December 5, 2017: Sensors
https://www.readbyqxmd.com/read/29194206/predictive-factors-for-visual-field-conversion-comparison-of-scanning-laser-polarimetry-and-optical-coherence-tomography
#7
Theresa Diekmann, Laura M Schrems-Hoesl, Christian Y Mardin, Robert Laemmer, Folkert K Horn, Friedrich E Kruse, Wolfgang A Schrems
PURPOSE: The purpose of this study was to compare the ability of scanning laser polarimetry (SLP) and spectral-domain optical coherence tomography (SD-OCT) to predict future visual field conversion of subjects with ocular hypertension and early glaucoma. METHODS: All patients were recruited from the Erlangen glaucoma registry and examined using standard automated perimetry, 24-hour intraocular pressure profile, and optic disc photography. Peripapillary retinal nerve fiber layer thickness (RNFL) measurements were obtained by SLP (GDx-VCC) and SD-OCT (Spectralis OCT)...
November 30, 2017: Journal of Glaucoma
https://www.readbyqxmd.com/read/29172994/amiloride-does-not-protect-retinal-nerve-fibre-layer-thickness-in-optic-neuritis-in-a-phase-2-randomised-controlled-trial
#8
Justin B McKee, Charles L Cottriall, John Elston, Simon Epps, Nikos Evangelou, Stephen Gerry, Christopher Kennard, Yazhuo Kong, Abigail Koelewyn, Wilhelm Kueker, Maria Isabel Leite, Jacqueline Palace, Matthew Craner
BACKGROUND: Recent basic and clinical evidence suggests amiloride may be neuroprotective in multiple sclerosis (MS) through the blockade of the acid sensing ion channel (ASIC). OBJECTIVE: To examine the neuroprotective efficacy of amiloride in acute optic neuritis (ON). METHODS: A total of 48 patients were recruited to a phase 2, double blind, single site, randomised controlled trial. Scanning laser polarimetry (GDx) at 6 months was the primary outcome measure and optical coherence tomography (OCT) and visual and electrophysiological measures were secondary outcome measures...
November 1, 2017: Multiple Sclerosis: Clinical and Laboratory Research
https://www.readbyqxmd.com/read/29166104/rapid-spectro-polarimetry-to-probe-molecular-symmetry-in-multiplex-coherent-anti-stokes-raman-scattering
#9
Thomas Würthwein, Maximilian Brinkmann, Tim Hellwig, Carsten Fallnich
We present the simultaneous detection of the spectrum and the complete polarization state of a multiplex coherent anti-Stokes Raman scattering signal with a fast division-of-amplitude spectro-polarimeter. The spectro-polarimeter is based on a commercial imaging spectrograph, a birefringent wedge prism, and a segmented polarizer. Compared to the standard rotating-retarder fixed-analyzer spectro-polarimeter, only a single measurement is required and an up to 21-fold reduced acquisition time is shown. The measured Stokes parameters allow us to differentiate between vibrational symmetries and to determine the depolarization ratio ρ by data post-processing...
November 21, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/29140357/experimental-evidence-for-partial-spatial-coherence-in-imaging-mueller-polarimetry
#10
Razvigor Ossikovski, Oriol Arteaga, Sang Hyuk Yoo, Enric Garcia-Caurel, Kurt Hingerl
We demonstrate experimentally the validity of the partial spatial coherence formalism in Mueller polarimetry and show that, in a finite spatial resolution experiment, the measured response is obtained through convolving the theoretical one with the instrument function. The reported results are of primary importance for Mueller imaging systems.
November 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/29131523/assessment-of-tissue-polarimetric-properties-using-stokes-polarimetric-imaging-with-circularly-polarized-illumination
#11
Ji Qi, Honghui He, Jianyu Lin, Yang Dong, Dongsheng Chen, Hui Ma, Daniel S Elson
Tissue depolarization and linear retardance are the main polarization characteristics of interest for bulk tissue characterization, and are normally interpreted from Mueller polarimetry. Stokes polarimetry can be conducted using simpler instrumentation and in a shorter time. Here we use Stokes polarimetric imaging with circularly polarized illumination to assess the circular depolarization and linear retardance properties of tissue. Results obtained were compared with Mueller polarimetry in transmission and reflection geometry respectively...
November 13, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/29092514/a-large-diameter-hollow-shaft-cryogenic-motor-based-on-a-superconducting-magnetic-bearing-for-millimeter-wave-polarimetry
#12
B R Johnson, F Columbro, D Araujo, M Limon, B Smiley, G Jones, B Reichborn-Kjennerud, A Miller, S Gupta
In this paper, we present the design and measured performance of a novel cryogenic motor based on a superconducting magnetic bearing (SMB). The motor is tailored for use in millimeter-wave half-wave plate (HWP) polarimeters, where a HWP is rapidly rotated in front of a polarization analyzer or polarization-sensitive detector. This polarimetry technique is commonly used in cosmic microwave background polarization studies. The SMB we use is composed of fourteen yttrium barium copper oxide (YBCO) disks and a contiguous neodymium iron boron (NdFeB) ring magnet...
October 2017: Review of Scientific Instruments
https://www.readbyqxmd.com/read/29092221/computational-polarimetric-microwave-imaging
#13
Thomas Fromenteze, Okan Yurduseven, Michael Boyarsky, Jonah Gollub, Daniel L Marks, David R Smith
We propose a polarimetric microwave imaging technique that exploits recent advances in computational imaging. We utilize a frequency-diverse cavity-backed metasurface, allowing us to demonstrate high-resolution polarimetric imaging using a single transceiver and frequency sweep over the operational microwave bandwidth. The frequency-diverse metasurface imager greatly simplifies the system architecture compared with active arrays and other conventional microwave imaging approaches. We further develop the theoretical framework for computational polarimetric imaging and validate the approach experimentally using a multi-modal leaky cavity...
October 30, 2017: Optics Express
https://www.readbyqxmd.com/read/29089638/a-quantitative-and-non-contact-technique-to-characterise-microstructural-variations-of-skin-tissues-during-photo-damaging-process-based-on-mueller-matrix-polarimetry
#14
Yang Dong, Honghui He, Wei Sheng, Jian Wu, Hui Ma
Skin tissue consists of collagen and elastic fibres, which are highly susceptible to damage when exposed to ultraviolet radiation (UVR), leading to skin aging and cancer. However, a lack of non-invasive detection methods makes determining the degree of UVR damage to skin in real time difficult. As one of the fundamental features of light, polarization can be used to develop imaging techniques capable of providing structural information about tissues. In particular, Mueller matrix polarimetry is suitable for detecting changes in collagen and elastic fibres...
October 31, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29082093/characterization-of-the-mechanical-properties-of-resected-porcine-organ-tissue-using-optical-fiber-photoelastic-polarimetry
#15
Alexa W Hudnut, Behzad Babaei, Sonya Liu, Brent K Larson, Shannon M Mumenthaler, Andrea M Armani
Characterizing the mechanical behavior of living tissue presents an interesting challenge because the elasticity varies by eight orders of magnitude, from 50Pa to 5GPa. In the present work, a non-destructive optical fiber photoelastic polarimetry system is used to analyze the mechanical properties of resected samples from porcine liver, kidney, and pancreas. Using a quasi-linear viscoelastic fit, the elastic modulus values of the different organ systems are determined. They are in agreement with previous work...
October 1, 2017: Biomedical Optics Express
https://www.readbyqxmd.com/read/29076304/review-of-the-emerging-role-of-optical-polarimetry-in-characterization-of-pathological-myocardium
#16
Iftikhar Ahmad
Myocardial infarction (MI), a cause of significant morbidity and mortality, is typically followed by microstructural alterations where the necrotic myocardium is steadily replaced with a collagen scar. Engineered remodeling of the fibrotic scar via stem cell regeneration has been shown to improve/restore the myocardium function after MI. Nevertheless, the heterogeneous nature of the scar patch may impair the myocardial electrical integrity, leading to the formation of arrhythmogenesis. Radiofrequency ablation (RFA) offers an effective treatment for focal arrhythmias where local heating generated via electric current at specific spots in the myocardium ablate the arrhythmogenic foci...
October 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/29061607/prevalence-and-risk-factors-of-eye-diseases-in-adult-patients-with-obstructive-sleep-apnoea-results-from-the-sle-e-p-y-cohort-study
#17
Emilio Pedrotti, Christian Luigi Demasi, Enrico Bruni, Francesca Bosello, Paolo Plinio Di Sarro, Mattia Passilongo, Adriano Fasolo, Nicola Gennaro, Alessandra De Gregorio, Marcello Ferrari, Giorgio Marchini
OBJECTIVES: To assess the occurrence of glaucoma, eyelid, corneal and macular disorders in a cohort of patients with obstructive sleep apnoea (OSA) diagnosed by overnight polysomnography and to investigate into the risk factors for the above eye diseases (EDs). DESIGN: Cross-sectional cohort study between 2014 and 2015. SETTING: Unit of Respiratory Medicine and Eye Clinic of the University of Verona. PARTICIPANTS: 431 consecutive patients were considered eligible...
October 22, 2017: BMJ Open
https://www.readbyqxmd.com/read/29053338/disaccharides-determination-a-review-of-analytical-methods
#18
Marta Pokrzywnicka, Robert Koncki
Disaccharides are determined mainly for dietetic purposes, hence the most analyses are carried out for food and drink samples. Its content can also be used to profile groceries in order to identify the origin and quality of the products. They also can be an indicator of the rate of metabolism as well as for the control of some technological and biotechnological processes. Unfortunately most of technological analysis are performed with nonselective polarimetry methods. Sugars due to specific physicochemical properties of compounds are difficult to determine with classical analytical techniques...
October 20, 2017: Critical Reviews in Analytical Chemistry
https://www.readbyqxmd.com/read/29046833/optical-techniques-for-cervical-neoplasia-detection
#19
REVIEW
Tatiana Novikova
This paper provides an overview of the current research in the field of optical techniques for cervical neoplasia detection and covers a wide range of the existing and emerging technologies. Using colposcopy, a visual inspection of the uterine cervix with a colposcope (a binocular microscope with 3- to 15-fold magnification), has proven to be an efficient approach for the detection of invasive cancer. Nevertheless, the development of a reliable and cost-effective technique for the identification of precancerous lesions, confined to the epithelium (cervical intraepithelial neoplasia) still remains a challenging problem...
2017: Beilstein Journal of Nanotechnology
https://www.readbyqxmd.com/read/29041328/dual-polarization-split-lenses
#20
Aarón Cofré, Asticio Vargas, Fabián A Torres-Ruiz, Juan Campos, Angel Lizana, María M Sánchez-López, Ignacio Moreno
We report the realization of polarization sensitive split lens configurations. While split lenses can be used to easily generate different types of controlled structured light patterns, their realization has been limited so far to scalar beams. Here we propose and experimentally demonstrate their generalization to vectorial split lenses, leading to light patterns with customized intensity and state of polarization. We demonstrate how these polarization split lenses can be experimentally implemented by means of an optical system using two liquid crystal spatial light modulators, each one phase modulating one orthogonal polarization component...
October 2, 2017: Optics Express
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