نتایج جستجو برای: polarizing microscope

تعداد نتایج: 47721  

1997
Rong-Chung Tyan Pang-Chen Sun Yeshayahu Fainman

We introduce a novel polarizing beam splitter that uses the anisotropic spectral reflectivity (ASR) characteristics of a high spatial frequency multilayer binary grating. By combining the form birefringence effect of a high spatial frequency grating with the resonant reflectivity of a periodic multilayer structure, the ASR characteristics for the two orthogonal linear polarizations are obtained...

Journal: :Cell 1995
Martin J Cohn Juan Carlos Izpisúa-Belmonte Helen Abud John K Heath Cheryll Tickle

Fibroblast growth factors (FGFs) act as signals in the developing limb and can maintain proliferation of limb bud mesenchyme cells. Remarkably, beads soaked in FGF-1, FGF-2, or FGF-4 and placed in the presumptive flank of chick embryos induce formation of ectopic limb buds, which can develop into complete limbs. The entire flank can produce additional limbs, but generally wings are formed anter...

Journal: :Reproduction, nutrition, development 1997
E Gómez H Uría

Several characteristics of oviductal cells, cultured under either polarizing or nonpolarizing conditions, were studied. In vitro produced bovine embryos tested the embryotrophic abilities of the respective conditioned media. Conditioned medium from the apical face of polarized cell monolayers supported higher rates of development to blastocyst and expanded blastocysts. In contrast, conditioned ...

2009
Devendra K Sahu

Thermally stimulated depolarization current (TSDC) characteristics of Polyvinyl Pyrrolidone (PVP) electrets are studies in the temperature range 30 to 210 C as functions of the polarizing field (5 to 100kV/cm) and polarizing temperature (40 to 80C). The TSDC spectra comprise two maxima, namely, β and α with their respective locations around 90 C and 172.5 C. These are attributed to dipoleorient...

Journal: :Journal of embryology and experimental morphology 1979
J A Maccabe B W Parker

When polarizing mesoderm from the posterior border of the 4-day chick limb bud is placed adjacent to anterior limb mesoderm and ectodermal ridge, the anterior ridge thickens and mesodermal outgrowth ensues, resulting in supernumerary limb structures. This apposition of anterior and posterior limb tissues can be accomplished by cutting off the apical one third of the limb bud and reimplanting it...

2012
T.M. Jordan J.C. Partridge N.W. Roberts

Dielectric multilayer reflectors that are non-polarizing are an important class of optical device and have numerous applications within optical fibres [1], dielectric waveguides [2] and LEDs [3]. Here we report analyses of a biological non-polarizing optical mechanism found in the broadband guanine-cytoplasm "silver" multilayer reflectors of three species of fish. Present in the fish stratum ar...

Journal: :Journal of embryology and experimental morphology 1982
D A Rowe J F Fallon

Impermeable barriers were inserted into the stage-20 to -21 leg bud to test whether or not such an interruption of diffusion of the proposed morphogen from the polarizing zone would result in failure of leg elements to develop anterior to the barrier. Tantalum foil was placed at somite levels 30/31 or mid-31 through the dorsoventral extent of the leg bud separating anterior from posterior mesod...

2018
Sanford C. Gordon Dimitri Landa

Much of contemporary political debate in the United States focuses on the issue of polarization: specifically, its causal antecedents and its consequences for policymaking and political conflict. In this article, we argue that partisan preference polarization – conventionally defined as the difference in the favored policy positions of legislators from the two major parties – is not a sufficien...

Journal: :Geoarchaeology-an International Journal 2022

From 2017, an unknown rural settlement in Contrada Castro at Corleone (Palermo Province, western Sicily) was investigated as part of the ‘Harvesting Memories Project’. The stratigraphic sequence, supported by radiocarbon dating, has demonstrated a reoccupation pre-Roman site during transition between Byzantine and Islamic periods. In particular, main occupation occurred late 8th–9th century whe...

Journal: :Indian journal of science and technology 2022

Objectives: The Phase transition scheme of Ferroelectric Liquid Crystal (FLC) sample has been studied in a temperature range 500C to 950C. Methods: material was procured from Merck, Germany and used as such without any further purification, for the measurement optical rotation transmittance. Polarizing Optical Microscopy (POM) technique different phases existing were observed by placing having ...

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