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https://www.readbyqxmd.com/read/28504887/co2-controlled-one-pot-synthesis-of-ab-aba-block-and-statistical-terpolymers-from-%C3%AE-butyrolactone-epoxides-and-co2
#1
Sebastian Kernbichl, Marina Reiter, Friederike Adams, Sergei Vagin, Bernhard Rieger
Terpolymerizations of (rac)-β-butyrolactone (BBL), cyclohexene oxide (CHO), and carbon dioxide were realized in one-pot reactions utilizing a Lewis acid BDI(CF3)-Zn-N(SiMe3)2 (1) catalyst. The type of polymerization can be regulated and switched between ring-opening polymerization (ROP) of BBL and CHO/CO2 copolymerization by the presence of CO2 in the reaction mixture. Applying 3 bar CO2 to the three-component system leads to similar reaction rates for copolymerization and ROP and therefore to a terpolymer with a statistical composition, whereas 40 bar CO2 affords exclusive copolymerization of CHO/CO2...
May 15, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28504754/performance-comparison-of-pseudo-inverse-and-maximum-likelihood-estimators-of-stokes-parameters-in-the-presence-of-poisson-noise-for-spherical-design-based-measurement-structures
#2
François Goudail
Estimation of the Stokes vector from N>4 intensity measurements is usually performed with the pseudo-inverse (PI) estimator, which is optimal when the noise that corrupts the measurements is additive and Gaussian. In the presence of Poisson shot noise, the maximum-likelihood (ML) estimator is different from the PI estimator, but is more complex to implement since it is not closed-form. We compare in this Letter the precisions obtained with the ML and the PI estimators in the presence of Poisson noise when using measurement structures based on spherical designs...
May 15, 2017: Optics Letters
https://www.readbyqxmd.com/read/28401949/inverting-polar-domains-via-electrical-pulsing-in-metallic-germanium-telluride
#3
Pavan Nukala, Mingliang Ren, Rahul Agarwal, Jacob Berger, Gerui Liu, A T Charlie Johnson, Ritesh Agarwal
Germanium telluride (GeTe) is both polar and metallic, an unusual combination of properties in any material system. The large concentration of free-carriers in GeTe precludes the coupling of external electric field with internal polarization, rendering it ineffective for conventional ferroelectric applications and polarization switching. Here we investigate alternate ways of coupling the polar domains in GeTe to external electrical stimuli through optical second harmonic generation polarimetry and in situ TEM electrical testing on single-crystalline GeTe nanowires...
April 12, 2017: Nature Communications
https://www.readbyqxmd.com/read/28386442/polarimetry-of-pinctada-fucata-nacre-indicates-myostracal-layer-interrupts-nacre-structure
#4
Rebecca A Metzler, Joshua A Jones, Anthony J D'Addario, Enrique J Galvez
The inner layer of many bivalve and gastropod molluscs consists of iridescent nacre, a material that is structured like a brick wall with bricks consisting of crystalline aragonite and mortar of organic molecules. Myostracal layers formed during shell growth at the point of muscle attachment to the shell can be found interspersed within the nacre structure. Little has been done to examine the effect the myostracal layer has on subsequent nacre structure. Here we present data on the structure of the myostracal and nacre layers from a bivalve mollusc, Pinctada fucata...
February 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28386426/celestial-polarization-patterns-sufficient-for-viking-navigation-with-the-naked-eye-detectability-of-haidinger-s-brushes-on-the-sky-versus-meteorological-conditions
#5
Gábor Horváth, Péter Takács, Balázs Kretzer, Szilvia Szilasi, Dénes Száz, Alexandra Farkas, András Barta
If a human looks at the clear blue sky from which light with high enough degree of polarization d originates, an 8-shaped bowtie-like figure, the yellow Haidinger's brush can be perceived, the long axis of which points towards the sun. A band of high d arcs across the sky at 90° from the sun. A person can pick two points on that band, observe the yellow brushes and triangulate the position of the sun based on the orientation of the two observed brushes. This method has been suggested to have been used on the open sea by Viking navigators to determine the position of the invisible sun occluded by cloud or fog...
February 2017: Royal Society Open Science
https://www.readbyqxmd.com/read/28384706/stokes-mueller-matrix-polarimetry-technique-for-circular-dichroism-birefringence-sensing-with-scattering-effects
#6
Quoc-Hung Phan, Yu-Lung Lo
No abstract text is available yet for this article.
April 1, 2017: Journal of Biomedical Optics
https://www.readbyqxmd.com/read/28383522/investigating-starch-gelatinization-through-stokes-vector-resolved-second-harmonic-generation-microscopy
#7
Nirmal Mazumder, Lu Yun Xiang, Jianjun Qiu, Fu-Jen Kao
The changes of the morphology during heating and the degree of crystallinity of dry and hydrated starch granules are investigated using second harmonic generation (SHG) based Stokes polarimetry. A spatial distribution of various polarization parameters, such as the degree of polarization (DOP), the degree of linear polarization (DOLP), and the degree of circular polarization (DOCP) are extracted and compared with the two dimensional second harmonic (SH) Stokes images of starch granules. The SH signal from hydrated and dry starch on heating differed significantly in DOLP and DOCP values, indicating that hydrated starch has a greater degree of ultrastructural amylopectin disorder...
April 6, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28380013/polarization-image-segmentation-of-radiofrequency-ablated-porcine-myocardial-tissue
#8
Iftikhar Ahmad, Adam Gribble, Iqbal Murtza, Masroor Ikram, Mihaela Pop, Alex Vitkin
Optical polarimetry has previously imaged the spatial extent of a typical radiofrequency ablated (RFA) lesion in myocardial tissue, exhibiting significantly lower total depolarization at the necrotic core compared to healthy tissue, and intermediate values at the RFA rim region. Here, total depolarization in ablated myocardium was used to segment the total depolarization image into three (core, rim and healthy) zones. A local fuzzy thresholding algorithm was used for this multi-region segmentation, and then compared with a ground truth segmentation obtained from manual demarcation of RFA core and rim regions on the histopathology image...
2017: PloS One
https://www.readbyqxmd.com/read/28366205/-the-origins-of-analysis-and-of-drugs-control
#9
O Lafont
Analytical concerns were quite ancient. As soon as the 12th century, Al-Chayzari searched drugs falsifications. During the 17th century, retort analysis was much practiced. Selective extraction constituted a great progress. During the 18th century, gas volumetric analysis appeared. Descroizilles created volumetric analysis in liquid phase, and that gave him the opportunity for creating acidi-alcalimetry methods. Following the works of Gay-Lussac and Thénard, Liebig invented an apparatus for performing elemental analysis of organic compounds...
March 30, 2017: Annales Pharmaceutiques Françaises
https://www.readbyqxmd.com/read/28352074/optimized-mass-spectrometry-analysis-workflow-with-polarimetric-guidance-for-ex-vivo-and-in-situ-sampling-of-biological-tissues
#10
Michael Woolman, Adam Gribble, Emma Bluemke, Jing Zou, Manuela Ventura, Nicholas Bernards, Megan Wu, Howard J Ginsberg, Sunit Das, Alex Vitkin, Arash Zarrine-Afsar
Spatially Targeted Mass Spectrometry (MS) analysis using survey scans with an imaging modality often requires consecutive tissue slices, because of the tissue damage during survey scan or due to incompatible sample preparation requirements between the survey modality and MS. We report two spatially targeted MS analysis workflows based on polarized light imaging guidance that use the same tissue sample for survey and targeted analysis. The first workflow is applicable for thin-slice analysis, and uses transmission-polarimetry-guided Desorption ElectroSpray Ionization Mass Spectrometry (DESI-MS), and confirmatory H&E histopathology analysis on the same slice; this is validated using quantitative digital pathology methods...
March 28, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28349895/low-temperature-magnetic-structure-of-cerhin5-by-neutron-diffraction-on-absorption-optimized-samples
#11
D M Fobes, E D Bauer, J D Thompson, A Sazonov, V Hutanu, S Zhang, F Ronning, M Janoschek
Two aspects of the ambient pressure magnetic structure of heavy fermion material CeRhIn5 have remained under some debate since its discovery: whether the structure is indeed an incommensurate helix or a spin density wave, and what is the precise magnitude of the ordered magnetic moment. By using a single crystal sample optimized for hot neutrons to minimize neutron absorption by Rh and In, here we report an ordered moment of [Formula: see text]. In addition, by using spherical neutron polarimetry measurements on a similar single crystal sample, we have confirmed the helical nature of the magnetic structure, and identified a single chiral domain...
May 4, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
https://www.readbyqxmd.com/read/28191819/snapshot-linear-stokes-imaging-spectropolarimeter-using-division-of-focal-plane-polarimetry-and-integral-field-spectroscopy
#12
Tingkui Mu, Shaun Pacheco, Zeyu Chen, Chunmin Zhang, Rongguang Liang
In this paper, the design and experimental demonstration of a snapshot linear-Stokes imaging spectropolarimeter (SLSIS) is presented. The SLSIS, which is based on division-of-focal-plane polarimetry with four parallel linear polarization channels and integral field spectroscopy with numerous slit dispersive paths, has no moving parts and provides video-rate Stokes-vector hyperspectral datacubes. It does not need any scanning in the spectral, spatial or polarization dimension and offers significant advantages of rapid reconstruction without heavy computation during post-processing...
February 13, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28187977/retinal-and-optic-nerve-degeneration-in-patients-with-multiple-sclerosis-followed-up-for-5-years
#13
Elena Garcia-Martin, Jose R Ara, Jesus Martin, Carmen Almarcegui, Isabel Dolz, Elisa Vilades, Laura Gil-Arribas, Francisco J Fernandez, Vicente Polo, Jose M Larrosa, Luis E Pablo, Maria Satue
PURPOSE: To quantify retinal nerve fiber layer (RNFL) changes in patients with multiple sclerosis (MS) and healthy controls with a 5-year follow-up and to analyze correlations between disability progression and RNFL degeneration. DESIGN: Observational and longitudinal study. PARTICIPANTS: One hundred patients with relapsing-remitting MS and 50 healthy controls. METHODS: All participants underwent a complete ophthalmic and electrophysiologic exploration and were re-evaluated annually for 5 years...
May 2017: Ophthalmology
https://www.readbyqxmd.com/read/28176895/advanced-endoscopic-imaging-in-gastric-neoplasia-and-preneoplasia
#14
Jonathan W J Lee, Lee Guan Lim, Khay Guan Yeoh
Conventional white light endoscopy remains the current standard in routine clinical practice for early detection of gastric cancer. However, it may not accurately diagnose preneoplastic gastric lesions. The technological advancements in the field of endoscopic imaging for gastric lesions are fast growing. This article reviews currently available advanced endoscopic imaging modalities, in particular chromoendoscopy, narrow band imaging and confocal laser endomicroscopy, and their corresponding evidence shown to improve diagnosis of preneoplastic gastric lesions...
2017: BMJ Open Gastroenterology
https://www.readbyqxmd.com/read/28168045/transient-peripapillary-retinoschisis-in-glaucomatous-eyes
#15
Josine van der Schoot, Koenraad A Vermeer, Hans G Lemij
Purpose. To investigate transient focal microcystic retinoschisis in glaucomatous eyes in images obtained with several imaging techniques used in daily glaucoma care. Methods. Images of 117 glaucoma patients and 91 healthy subjects participating in a large prospective follow-up study into glaucoma imaging were reviewed. Participants were measured with spectral domain optical coherence tomography (SD-OCT), scanning laser polarimetry (SLP), scanning laser tomography (SLT), and standard automated perimetry (SAP)...
2017: Journal of Ophthalmology
https://www.readbyqxmd.com/read/28157922/liquid-crystal-based-mueller-matrix-spectral-imaging-polarimetry-for-parameterizing-mineral-structural-organization
#16
James C Gladish, Donald D Duncan
Herein, we discuss the remote assessment of the subwavelength organizational structure of a medium. Specifically, we use spectral imaging polarimetry, as the vector nature of polarized light enables it to interact with optical anisotropies within a medium, while the spectral aspect of polarization is sensitive to small-scale structure. The ability to image these effects allows for inference of spatial structural organization parameters. This work describes a methodology for revealing structural organization by exploiting the Stokes/Mueller formalism and by utilizing measurements from a spectral imaging polarimeter constructed from liquid crystal variable retarders and a liquid crystal tunable filter...
January 20, 2017: Applied Optics
https://www.readbyqxmd.com/read/28113877/automated-diagnosis-of-glaucoma-using-empirical-wavelet-transform-and-correntropy-features-extracted-from-fundus-images
#17
Shishir Maheshwari, Ram Bilas Pachori, U Rajendra Acharya
Glaucoma is an ocular disorder caused due to increased fluid pressure in the optic nerve. It damages the optic nerve subsequently causes loss of vision. The available scanning methods are Heidelberg Retinal Tomography (HRT), Scanning Laser Polarimetry (SLP) and Optical Coherence Tomography (OCT). These methods are expensive and require experienced clinicians to use them. So, there is a need to diagnose glaucoma accurately with low cost. Hence, in this paper, we have presented a new methodology for an automated diagnosis of glaucoma using digital fundus images based on Empirical Wavelet Transform (EWT)...
March 22, 2016: IEEE Journal of Biomedical and Health Informatics
https://www.readbyqxmd.com/read/28107928/determination-of-d-lactide-content-in-lactide-stereoisomeric-mixture-using-gas-chromatography-polarimetry
#18
Lidong Feng, Xinchao Bian, Zhiming Chen, Sheng Xiang, Yanlong Liu, Bin Sun, Gao Li, Xuesi Chen
An analytical method has been proposed to quantify the D-lactide content in a lactide stereoisomeric mixture using combined gas chromatography and polarimetry (GC- polarimetry). As for a lactide stereoisomeric mixture, meso-lactide can be determined quantitatively using GC, but D- and L-lactides cannot be separated by the given GC system. The composition of a lactide stereoisomeric mixture is directly relative to its specific optical rotation. The specific optical rotations of neat L-lactide were obtained in different solutions, which were -266...
March 1, 2017: Talanta
https://www.readbyqxmd.com/read/28105702/hydrodynamic-effects-in-soft-matter-self-assembly-the-case-of-j-aggregates-of-amphiphilic-porphyrins
#19
REVIEW
Josep M Ribo, Zoubir El-Hachemi, Oriol Arteaga, Adolf Canillas, Joaquim Crusats
Chiral J-aggregates of achiral amphiphilic porphyrins (4-sulfonatophenyl and aryl meso-substituted porphyrins) show several effects under the hydrodynamic forces of common stirring. These effects can be classified as pure mechanic (e. g. elasticity, plasticity and breaking of the self-assembly non-covalent bonding) and chemically selective as detected in the formation/growth of the nanoparticles. Diastereoselective, enantioselective and, depending on the sign of chiral shear forces, even enantiospecific selections have been described...
January 20, 2017: Chemical Record: An Official Publication of the Chemical Society of Japan ... [et Al.]
https://www.readbyqxmd.com/read/28094977/crystallographic-mapping-of-guided-nanowires-by-second-harmonic-generation-polarimetry
#20
Lior Neeman, Regev Ben-Zvi, Katya Rechav, Ronit Popovitz-Biro, Dan Oron, Ernesto Joselevich
The growth of horizontal nanowires (NWs) guided by epitaxial and graphoepitaxial relations with the substrate is becoming increasingly attractive owing to the possibility of controlling their position, direction, and crystallographic orientation. In guided NWs, as opposed to the extensively characterized vertically grown NWs, there is an increasing need for understanding the relation between structure and properties, specifically the role of the epitaxial relation with the substrate. Furthermore, the uniformity of crystallographic orientation along guided NWs and over the substrate has yet to be checked...
February 8, 2017: Nano Letters
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