Abstract: : Purpose: To determine the wavelength dependence of corneal birefringence. Methods: A corneal polarimeter described previously (ARVO 2001; IOVS 2002;43:82-86) was modified to incorporate a multi-spectral light source and a video detector. Corneal birefringence was measured by using a variable retarder to null the fourth Purkinje image viewed through crossed polarizers. The corneas of five eyes of five normal subjects were measured three times at each of several wavelengths from 440 to 700 nm. Results: Corneal axis did not vary significantly with wavelength. Corneal retardance ranged from 85-143 nm in the five subjects. Pooling variances across subjects, the within wavelength s.d. was 10.2 nm and the between wavelength s.d. was 5.3 nm. Conclusion: Corneal birefringence was constant across visible wavelengths. This is consistent with the frequently assumed mechanism of form birefringence, i.e., birefringence due to oriented collagen fibrils in the corneal stroma. ...
Corneal birefringence affects polarization-sensitive optical measurements of the eye. Recent literature supports the idea that corneal birefringence is biaxial, although with some disagreement among reports and without considering corneas with very low values of central retardance. This study measured corneal retardation in eyes with a wide range of central corneal retardance by means of scanning laser polarimetry (GDx-VCC™, Carl Zeiss Meditec, Inc.), which computes the retardance and slow axis of the cornea from images of the bow tie pattern formed by the radial birefringence of the macula. Measurements were obtained at many points on the cornea by translating the instrument. Data were compared to calculations of the retardation produced by a curved biaxial material between two spherical surfaces. Most corneas showed one or two small areas of zero retardance where the refracted ray within the cornea aligned with an optical axis of the material. The retardation patterns in these corneas could ...
Photoreceptors in the central macula are prone to damage in many progressive sight threatening diseases, including AMD. Direct assessment of these photoreceptors is difficult in the aging eye, making indirect techniques particularly valuable. Indirect techniques must utilize unique optical signatures to isolate structures of interest and permit quantitative metrics for comparison. As a complementary technique for assessing the central macula, SLP imaging can utilize the phase retardation signal generated by the photoreceptor axons of the HFL, the only known birefringent structure in the central macula, to selectively study the central macular photoreceptor density and regularity. Similar to the nerve fiber layer (NFL), the magnitude of the phase retardation signal in the central macula would be proportional to the number of axons that make up the Henle fiber layer at any given eccentricity. These central photoreceptor axons splay out in a well-organized, radially symmetric pattern,18 suggesting ...
The |i|Journal of Biomedical Optics|/i| (JBO) publishes peer-reviewed papers on the use of novel optical systems and techniques for improved health care and biomedical research.
Nearly all circular dichroism (CD) and linear dichroism (LD) spectrometers use a photoelastic modulator (PEM) in which an optical element is stressed using a high-tension voltage (HT) signal to induce birefringence. The birefringence consequently produces a phase difference between perpendicular polarization states of light passing through the PEM that is appropriate to CD or LD measurements. However, even without external stress (i.e., at zero HT) the PEM exhibits an inherent static birefringence. This article discusses the characterization of the static birefringence inherent to a PEM and its effect on the measurement of CD and LD, as well as the development and implementation of a novel model that accommodates for the presence of static birefringence. The model is validated with CD and LD experiments using purely chiral or linearly structured molecules (camphorsulfonic acid and chrysazin).. PDF Article ...
In this dissertation, liquid crystal (LC) materials and devices are investigated in order to meet the challenges for photonics and displays applications. We have studied three kinds of liquid crystal materials: positive dielectric anisotropic LCs, negative dielectric anisotropic LCs, and dual- frequency LCs. For the positive dielectric anisotropic LCs, we have developed some high birefringence isothiocyanato tolane LC compounds with birefringence ~0.4, and super high birefringence isothiocyanato biphenyl-bistolane LC compounds with birefringence as high as ~0.7. Moreover, we have studied the photostability of several high birefringence LC compounds, mixtures, and LC alignment layers in order to determine the failure mechanism concerning the lifetime of LC devices. Although cyano and isothiocyanato LC compounds have similar absorption peaks, the isothiocyanato compounds are more stable than their cyano counterparts under the same illumination conditions. This ultraviolet-durable performance of
We report an optical film with electrically tunable birefringence in which the liquid crystals (LCs), mixed with the host polymer, form longrange ordering. The film was prepared through polymerization without phase separation between the LCs and polymers. Driving voltage below 30 V for full switching of birefringence is achieved in a 6 μm-thick film. Electro-optical investigations for the film suggest that the long-range ordering of the LCs mixed in the film caused by polymerization lead to rotations of the LCs as well as optical anisotropy in the film. These films with electrically tunable birefringence could have applications as flexible light modulators and phase retardation films for 2D-3D image switching. © 2014 Optical Society of America. ...
The |i|Journal of Biomedical Optics|/i| (JBO) publishes peer-reviewed papers on the use of modern optical technology for improved health care and research.
Poly-3-hexylthiophene (P3HT) nanofibers are 1D crystalline semiconducting nanostructures, which are known for their application in photovoltaics. Due to the internal arrangement, P3HT nanofibers possess optical anisotropy, which can be enhanced on a macroscale if nanofibers are aligned. Alternating electric field, applied to a solution with dispersed nanofibers, causes their alignment and serves as a method to produce solid layers with ordered nanofibers. The transmission ellipsometry measurements demonstrate the dichroic absorption and birefringence of ordered nanofibers in a wide spectral range of 400-1700 nm. Moreover, the length of nanofibers has a crucial impact on their degree of alignment. Using electric birefringence technique, it is shown that external electric field applied to the solution with P3HT nanofibers can cause direct birefringence modulation. Dynamic alignment of dispersed nanofibers changes the refractive index of the solution and, therefore, the polarization of transmitted ...
Sex chromosomes in crane-fly spermatocytes move polewards at anaphase after the autosomes have reached the poles. In Nephrotoma abbreviate the sex chromosomes are 8 μm long by 3.5 μm wide and have two orientations when they move: the long axis of the sex chromosome is either perpendicular or parallel to the spindle axis. We assume (1) that when a sex chromosome is perpendicular to the spindle axis it has a chromosomal spindle fibre to each pole, one from each kinetochore, as in other species; and (2) that when a sex chromosome is parallel to the spindle axis each kinetochore has spindle fibres to both poles, i.e. that the latter sex chromosomes are maloriented.. We irradiated one kinetochore of one sex chromosome using an ultraviolet microbeam. When both sex chromosomes were normally oriented, irradiation of a single kinetochore permanently blocked movement of both sex chromosomes. Irradiation of non-kinetochore chromosomal regions or of spindle fibres did not block movement, or blocked ...
Over the past twenty years our understanding of polymer solutions has undergone a dramatic evolution. New methods and concepts have extended the frontier of the theory from dilute solutions in which polymers move independently of each other, to concentrated solutions where many polymersentangle with each other. This book provides a comprehensive account of the modern theory for the dynamical properties of polymer solutions. This includes viscoelasticity, diffusion, dynamic light scattering and flow and electric birefringence. Nonlinear viscoelasticity is discussed in detail on thebasis of molecular dynamical models. The book fills a gap between classical theory and modern developments and constructs a consistent picture for the dynamics of polymer solutions over the entire concentration range.
Cascadability and simplicity of design and operation are primary attributes of a novel electrooptic polarization transformer for reset-free endless polarization control that allows general polarization transformations from any arbitrarily varying input and into any arbitrarily varying output polarization by producing adjustment elliptical birefringence of constant total phase retardation in a single-mode waveguide. Here, a particular transformation is obtained by adjusting the azimuth of linear birefringence and the ratio of linear to circular birefringence. In this integrated-optic realization, the endless polarization transformer includes at least one cascadable transformer section comprising a first TE←→TM mode converter followed by a first TE/TM phase shifter followed by a second TE←→TM mode converter and a second TE/TM phase shifter. The sections are formed over a birefringent waveguide capable of supporting propagation of TE and TM optical signal modes.
TY - JOUR. T1 - Inverse Thermoreversible Mechanical Stiffening and Birefringence in a Methylcellulose/Cellulose Nanocrystal Hydrogel. AU - Hynninen, Ville. AU - Hietala, Sami. AU - McKee, Jason R.. AU - Murtomäki, Lasse. AU - Rojas Gaona, Orlando. AU - Ikkala, Olli. AU - Nonappa, Nonappa. PY - 2018/5/7. Y1 - 2018/5/7. N2 - We show that composite hydrogels comprising methyl cellulose (MC) and cellulose nanocrystal (CNC) colloidal rods display a reversible and enhanced rheological storage modulus and optical birefringence upon heating, i.e., inverse thermoreversibility. Dynamic rheology, quantitative polarized optical microscopy, isothermal titration calorimetry (ITC), circular dichroism (CD), and scanning and transmission electron microscopy (SEM and TEM) were used for characterization. The concentration of CNCs in aqueous media was varied up to 3.5 wt % (i.e, keeping the concentration below the critical aq concentration) while maintaining the MC aq concentration at 1.0 wt %. At 20 °C, MC/CNC ...
Polydisperse fiber networks are the basis of many natural and manufactured structures, ranging from high-performance biobased materials to components of living cells and tissues. The formation and behavior of such networks are given by fiber properties such as length and stiffness as well as the number density and fiber-fiber interactions. Studies of fiber network behavior, such as connectivity or rigidity thresholds, typically assume monodisperse fiber lengths and isotropic fiber orientation distributions, specifically for nano scale fibers, where the methods providing time-resolved measurements are limited. Using birefringence measurements in a microfluidic flow-focusing channel combined with a flow stop procedure, we here propose a methodology allowing investigations of length-dependent rotational dynamics of nanoscale polydisperse fiber suspensions, including the effects of initial nonisotropic orientation distributions. Transition from rotational mobility to rigidity at entanglement ...
Birefringent materials have a wide range of optical applications. Single crystals of calcium carbonate and barium borate have been well known as inorganic birefringent materials. Organic single crystals such as urea have also been known to show birefringence. Since birefringence is related to crystal structures, studies on molecular structures and packing in a crystal are important. In 1957, birefringence of tetrakis(4-phenylphenyl)silane was reported (Hinch & Krc, 1957). Recently, birefringence of single crystals of phenyl-substituted linear oligosilanes and their application to polarizers have been reported (Matsumoto & Tanaka, 2008). From these results, crystals of phenyl-substituted silicon compounds seem interesting as potential optical materials. We report herein the synthesis and X-ray crystal analysis of a phenyl-substituted cyclotetrasilane.. The coupling of 1,3-dibromo-1,1,3,3-tetra-tert-butyl-2,2-diphenyltrisilane and dichlorodiisopropylsilane with lithium in tetrahydrofuran (THF) ...
The results of optical modeling of biological tissues polycrystalline multilayer networks have been presented. Algorithms of reconstruction of parameter distributions were determined that describe the linear and circular birefringence. For the separation of the manifestations of these mechanisms we propose a method of space-frequency filtering. Criteria for differentiation of benign and malignant tissues of the women reproductive sphere were found ...
The processing of optical polymers in the production of liquid crystal displays (LCDs) and lenses tends to produce birefringence in the materials. Man
... ,In finance, portfolio performance assessment is an important area of research. The two popular indices of performance are the Jensens alpha and the Sharpe index. However there are a number of shortcomings of the above measures that have been highlighted in the literature. We propose a new measure of performance
An electrically dimmable rear-view mirror for motor vehicles of simple and robust construction, suitable for use as an outside mirror or as an interior mirror possessing a transmission layer which is composed of a PLZT ceramic, on which a linear birefringence can be imposed by means of a controlling electric field. The transmission layer is located between a linear polarizer and a reflective layer, the latter being designed as a dielectric multilayer arrangement. Suitable comb-type electrodes are located on that side of the reflective layer which faces away from the transmission layer and, if appropriate, on that side of the polarizer which faces the transmission layer, the function of these comb-type electrodes being to generate the controlling field. The polarizer defines the direction of polarization, which is inclined at 45 with respect to the field direction and/or the optical axis of the transmission layer. The strength of the electric field controlling the dimming effect is regulated in a manner
O. Mykhaylyk. Soft Matter Analytical Laboratory, Department of Chemistry, The University of Sheffield, Sheffield, S3 7HF, UK. Since polymeric liquids subjected to an external field (flow) often respond with a related anisotropy of their refractive index and stress, flow birefringence is commonly used for structural characterization of these materials. In this respect, rotational geometries are well suited for visual observations of the flow and, consequently, mechano-optical rheology of polymeric liquids. New applications of a rheo-optical method based on a combination of rotational rheology and a recently developed optical technique - shear-induced polarized light imaging (SIPLI) are presented [1]. Simultaneous rheo-optical studies using rheo-SIPLI have already been successfully used for characterization of self-assembled copolymers and liquid crystals [1, 2]. The proposed rheo-optical method is also effective for studying flow-induced crystallization of semi-crystalline polymers (FIC) [3]. ...
Equipment in the colloidal and particle technology laboratories includes an atomic force microscope, a dynamic light scattering apparatus, a flow birefringence system, an imaging ellipsometer, a Brewster angle microscope, Langmuir troughs for BAM analysis and spectroscopic analysis of monolayers at liquid/vapor and liquid/liquid interfaces, Sensadyne bubble tensiometer, Cahn dynamic contact angle system, an image analysis system for sessile and pendant drop analysis, HPLC with evaporative mass and UV detectors, particle size analyzers, various testers for powder flow and mechanics, and turbulent flow heat transfer and drag reduction circulation loops.. ...
waveplate, Phase retardation plate, Phase plates, compensator, retarder, Zo Order, Lo Order, Zero Order, Low Order, Crystal, Quartz, shifter, polarization rotators, birefringence, electro-optic High, Energy, Waveplates
Abstract: Gravitational waves (GWs) provide an excellent opportunity to test the gravity in the strong gravitational fields. In this article, we calculate the waveform of GWs, produced by the coalescence of compact binaries, in an extension of the Chern-Simons gravity by including higher derivatives of the coupling scalar field. By comparing the two circular polarization modes, we find the effects of amplitude birefringence and velocity birefringence of GWs in their propagation caused by the parity violation in gravity, which are explicitly presented in the GW waveforms by the amplitude and phase modifications respectively. Combining the two modes, we obtain the GW waveforms in the Fourier domain, and find that the deviations from those in General Relativity are dominated by effects of velocity birefringence of GWs. In addition, we also map the effects of the parity violation on the waveform onto the parameterized post-Einsteinian (PPE) framework and identify explicitly the PPE parameters ...
Faint levels of circular polarization (Stokes V) have been detected in several relativistic jets. While typically less than a few percent, circular polarization can give us critical insight into the underlying nature of the jet plasma. Circular polarization can be produced through a process known as linear birefringence, in which initially linearly polarized emission produced in one region of the jet is altered by Faraday rotation as it propagates through other regions of the jet with distinct magnetic field orientations. Recently, Marscher has developed the Turbulent Extreme Multi-Zone (TEMZ) model for blazar emission, in which turbulent plasma crossing a standing shock in the jet is represented by a collection of thousands of individual plasma cells, each with distinct magnetic field orientation. In order to test whether the TEMZ model can reproduce circularly polarized radiation at levels comparable to those observed in blazars, I have developed a numerical algorithm to solve the full Stokes
Ammonium dihydrogen phosphate (ADP), also and better known as monoammonium phosphate (MAP) in order not to confuse it with adenosine diphosphate (ADP), with formula NH4H2PO4, is formed when a solution of phosphoric acid is added to ammonia until the solution is distinctly acidic. It crystallizes in tetragonal prisms. Monoammonium phosphate is often used in the blending of dry agricultural fertilizers. It supplies soil with the elements nitrogen and phosphorus in a form usable by plants. The compound is also a component of the ABC powder in some dry chemical fire extinguishers. This substance is also supplied in an emerald green, amethyst, aquamarine and any other color available, crystal growing box kit for children. Solid monoammonium phosphate shows a dissociation pressure of ammonia of 0.05 mm Hg at 125 °C based on the decomposition reaction as follows: NH4H2PO4(s) ⇌ NH3(g) + H3PO4(l) ADP is a widely used crystal in the field of optics due to its birefringence properties. As a result of ...
A multilayer that comprises ultra-thin metal and dielectric films has been investigated and applied as a layered metamaterial. By arranging metal and dielectric films alternatively and symmetrically, the equivalent admittance and refractive index can be tailored separately. The tailored admittance and refractive index enable us to design optical filters with more flexibility. The admittance matching is achieved via the admittance tracing in the normalized admittance diagram. In this work, an ultra-thin light absorber is designed as a multilayer composed of one or several cells. Each cell is a seven-layered film stack here. The design concept is to have the extinction as large as possible under the condition of admittance matching. For a seven-layered symmetrical film stack arranged as Ta2O5 (45 nm)/ a-Si (17 nm)/ Cr (30 nm)/ Al (30 nm)/ Cr (30 nm)/ a-Si (17 nm)/ Ta2O5 (45 nm), its mean equivalent admittance and extinction coefficient over the visible regime is 1.4+0.2i and 2.15, respectively. ...
Among the signs of activity in excitable membranes, the action current (electrical spike) has been extensively studied. Recently, a new approach with optical methods has been rewarding. In nerves, a transient, rapid change of light scattering, birefringence and induced fluorescence can be observed during the passage of the action current. These optical effects are synchronous with the electrical spike and are therefore called the optical spikes. Birefringence decreases during excitation in the giant axon of the squid, the walking nerves of Maia, the vagus nerve of the rabbit, but it increases in the olfactory nerve of the pike, which contains 4 million nonmedullated nerve fibres. Light scattering increases or decreases depending on the angle of observation. Vitally stained nerves with fluorescent probes show an increase and a shift in the wavelength distribution of the fluorescent spike. ...
In previous papers on the micellar organization of the nerve fibre, attention has been directed almost entirely to the lipoid-containing sheaths. Polarized light and X-ray diffraction studies have emphasized the similarity of the architecture of these structures over a wide range of animal forms, from the highly myelinated nerves of vertebrates to the so-called non-medullated fibres of invertebrates (Schmitt, Bear and Clark 1935; see preceding paper for other references). To date little more than a beginning has been made with analysis of the ultrastructure of the axoplasm. This has been due largely to technical difficulties arising from the small size and weak birefringence of the axons so far studied, from the unfavourable position of the axis cylinder within more or less complex sheaths, and from the extreme sensitivity of this colloid to the action of reagents. Valentin (1861), Klebs (1865), v. Ebner (1882), and Friedlaender (1889), found no birefringence in the fresh axis cylinder, although ...
0229] Using the two active and one passive dithering systems of the optical display system 640 is it possible to obtain eight copies of the original image, if desired, namely that provided at pixel 660, for example. Such eight copies may be obtained for every field for every frame, if desired and, thus, provide a macro pixel effectively about eight times the size of the pixel 660. In another embodiment, the data picked off the incoming analog signal or other video signal that operates the pixel 660, e.g., to turn it on or off, may be selected at the appropriate time to drive the pixel 660; and subsequently the pixel 661 may be operated as a function of information picked off the incoming video or analog signal representing the desired operation of the pixel 661 for interlaced fields operation of a conventional NTS or PAL system. However, additionally, if desired, the information from the incoming signal also could be picked off to represent the on/off or intensity effect of a pixel presented at ...
In between stress and strain, which one is the more fundamental physical quantity? Or is it the case that each is defined independent of the other and so nothing can be said about their order? Is this the case? To begin with these questions, consider the fact that first we have to apply a force to an object and it is only then that the object is observed to have been deformed or strained. Accordingly, one may say that forces produce strains, and therefore, it seems that stress has to be more fundamental. If so, how come stress cannot be measured directly? This is the paradox I would like to address here. Of course, to begin with, my position is that you can never directly measure stress. I have read somewhere an argument (and forgot exactly where!) that even in photoelasticity what you really measure is strain. The argument, essentially, is this: Birefringence arises because the molecular chains in the photoelastic polymer get stretched. (In case of crystals, "stress-induced" birefringence ...
In between stress and strain, which one is the more fundamental physical quantity? Or is it the case that each is defined independent of the other and so nothing can be said about their order? Is this the case? To begin with these questions, consider the fact that first we have to apply a force to an object and it is only then that the object is observed to have been deformed or strained. Accordingly, one may say that forces produce strains, and therefore, it seems that stress has to be more fundamental. If so, how come stress cannot be measured directly? This is the paradox I would like to address here. Of course, to begin with, my position is that you can never directly measure stress. I have read somewhere an argument (and forgot exactly where!) that even in photoelasticity what you really measure is strain. The argument, essentially, is this: Birefringence arises because the molecular chains in the photoelastic polymer get stretched. (In case of crystals, "stress-induced" birefringence ...
We theoretically propose a method to enhance dramatically a magnetochiral (MC) effect by using the photonic crystals composed of a multiferroic material. The MC effect, the directional birefringence even for unpolarized light, is so small that it has been difficult to observe experimentally. Two kinds of periodic structures are investigated: (a) a multilayer and (b) a stripe composed of a magnetochiral material and air. In both cases, the difference in reflectivity between different magnetization directions is enhanced by a factor of hundreds compared with a bulk material ...
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The eyes follow a typical scan path across the text, in the appropriate direction depending upon the language of the propranollol (e. Clin Vis Sri.
An optical film includes a layer of simultaneously biaxially stretched polyolefin film that is substantially non-absorbing and non-scattering for at least one polarization state of visible light. The layer has x, y, and z orthogonal indices of refraction where at least two of the orthogonal indices of refraction are not equal. The layer has an in-plane retardance of 100 nm or less and an out-of-plane retardance of 50 nm or greater.
A reflective polarizer and a dichroic polarizer are combined to provide an improved optical polarizer. The dichroic and reflective polarizers are typically in close proximity to each other, and are preferably bonded together to eliminate the air gap between the polarizers. The combination of the two polarizers provides a high reflectivity of one polarization and high transmission for the perpendicular polarization from the reflective polarizer side of the combined polarizer, and high absorption and transmission for light of orthogonal polarization from the dichroic polarizer side. The combination also reduces iridescence as seen in transmission and when viewed in reflection from the dichroic polarizer side. The increased extinction ratio and low reflectivity of the optical polarizer allows use of a lower extinction ratio dichroic polarizer in applications requiring a given extinction ratio and high transmission.
The two independent refractive indices of anisotropic crystals are quantified in terms of their birefringence, a measure of the difference in refractive index.
The authors demonstrate a high performance electrically controlled birefringence (ECB) mode with solution-derived La{sub 2}O{sub 3} films at various molar concentrations. Uniform and homogeneous liquid crystal (LC) alignment was spontaneously achieved on the La{sub 2}O{sub 3} films for lanthanum concentrations at ratios greater than and equal to 0.2. A preferred orientation of LC molecules appeared along the filling direction, and the LC alignment was maintained via van der Waals force by nanocrystals of the La{sub 2}O{sub 3} films. The LC alignment mechanism was confirmed by x-ray photoelectron spectroscopy and high-resolution transmission electron microscopy analysis. Superior electro-optical characteristics of the ECB cells constructed with solution-derived La{sub 2}O{sub 3} films were observed, which suggests that the proposed solution-derived La{sub 2}O{sub 3} films have strong potential for use in the production of advanced LC displays. ...
The export of the calcitic platelets (coccoliths) of coccolithophores to the sea floor acts as a long-term sink of carbon. In order to understand the effects of current ocean acidification on coccolithophore calcification, it is important to estimate the amount of calcite that is bound in single coccoliths, which - due to their minuteness (1-10 μm) - cannot be individually weighed. To estimate single coccolith weights, this study takes advantage of the birefringence method (Beaufort, 2005), which links the interference color of calcite under polarized light with calcite thickness. Two similar techniques, one using crossed-polarized light (XPL) and one using circular polarized light (CPL), were tested to compare coccolith weight estimates of cultured single clones of Gephyrocapsa oceanica, which - in a previous study (Rickaby et al., 2010) - were grown in increasing concentrations of dissolved inorganic carbon (DIC) but constant pH-levels (~8.1) to reflect long-term buffering of the ocean. In ...
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Our results identify a dmd morpholino cocktail that induces a high penetrance of muscle lesions and strongly resembles the zebrafish dmd mutant phenotype. We also show that the HDAC inhibitor TSA rescues both dmd-MO and dmd mutant muscle lesions. By comparing different approaches to scoring muscle lesions, our study confirms a previous report 13 that simple assessment of the muscle birefringence pattern in whole larvae, using a stereomicroscope, is a reliable approach to scoring the dmd-MO or dmd mutant phenotype following chemical treatment. Thus, our work identifies optimal morpholino and phenotypic scoring approaches for dystrophic zebrafish, further enhancing the zebrafish dmd model for rapid and cost-effective small molecule screening.. Our work provides additional support for using cocktails of non-overlapping morpholinos targeted against a single gene in order to provide more robust knock down and reduce non-specific morpholino toxicity than by using individual morpholinos 26,29,30,31. We ...
!%Carl Zeiss MicroImaging Inc.s%! Axio Scope.A1 offers polarization microscopy. With minimal effort, six versions of the microscope can be specifical
Optically birefringent microstructures are formed within fluoride films that are produced on uranium dioxide by hydrofluorination. The positive molar volume change of the reaction produces nonuniform tensile and compressive stresses around sites of surface roughness which result in optical double refraction.
A projection system includes a light source producing illumination light, an imager disposed to receive the illumination light, and a projection lens disposed to receive the illumination light from the imager. The imager includes an intrinsic polarizer. The intrinsic polarizer can be an intrinsic polarizer stack including a U.V. curable adhesive.
Toy or novelty including a first polarizer and a second polarizer movable relative to the first polarizer. In a first mode, the first and second polarizers interact to be reflective, and in a second mode, the first and second polarizers is transmissive. The toy may further include an object or image located adjacent the second polarizer, wherein the object or image is viewable through the first and second polarizers in the second mode.
Look at Figure 1, for example; this is a 30 µm thick rock thin-section as viewed between crossed polarizers using a 4X objective for a visual magnification of 40X. The individual mineral grains that make up this rock section are all lying at different orientations, and showing many shades of white and gray. When I view this figure filling up my monitor screen, I can go from grain to grain and name off colors: snow white, off- white, bone, ivory, cream, steel gray, bluish gray, greenish gray, light gray, medium gray, dark gray, charcoal, blue-green gray, olive gray, slate gray, gun metal, mushroom, etc. What I need, however, are not these often-creative verbal descriptions, but a value in nanometers, that the color I am looking at corresponds to; this is why I prefer a Michel-Lévy Interference Color Chart with colors printed as accurately as possible, but with the names of the colors as well. Only with an accurate determination of interference color can I obtain the characteristic birefringence ...
PANDA Polarization Maintaining (PM) fibers are designed with high performance properties including excellent birefringence and low attenuation. Corning offers the broadest portfolio of PANDA PM fibers from wavelengths of 400-1550nm and designs such as High NA and Flame Retardant coatings.
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The colours in the image are the result of birefringence and relate to the residual strain in the polystyrene. The pattern of strain is indicative of the flow of material during the injection process and it highlights the injection point (known as a sprue) which can also be identified by a small lump on the surface; the molecular alignment is greatest near this point. Towards the edges of the ruler and along its length, the material becomes more relaxed and as the molecular alignment falls, the retardation of light is less. If heated above the glass transition temperature of polystyrene (about 100 °C), the material will tend to relax, particularly near the sprue. This will result in a wrinkling of the component ...
Video articles in JoVE about muscular dystrophies include Isometric and Eccentric Force Generation Assessment of Skeletal Muscles Isolated from Murine Models of Muscular Dystrophies, Quantitative Magnetic Resonance Imaging of Skeletal Muscle Disease, Analysis of Zebrafish Larvae Skeletal Muscle Integrity with Evans Blue Dye, Transplantation of Induced Pluripotent Stem Cell-derived Mesoangioblast-like Myogenic Progenitors in Mouse Models of Muscle Regeneration, In Situ Immunofluorescent Staining of Autophagy in Muscle Stem Cells, In Vivo Modeling of the Morbid Human Genome using Danio rerio, Analysis of Skeletal Muscle Defects in Larval Zebrafish by Birefringence and Touch-evoke Escape Response Assays, Isolation and Immortalization of Patient-derived Cell Lines from Muscle Biopsy for Disease Modeling, Dos and Donts in the Preparation of Muscle Cryosections for Histological Analysis, Analysis of Embryonic and Larval Zebrafish Skeletal Myofibers from Dissociated Preparations,