Calcite prism

Calprismin, a novel member of mol-luskan shell proteins. Calprismin is a glycosylated protein (Mr 38 kDa) isolated from the shell calcitic prisms of the Mediterranean fan mussel Pinna no-hUis. It is soluble in acetic acid, and is acidic due to its high Asp content. It has been assumed that calprismin may act as calcite crystal-binding rather than a Ca -binding protein [F. Marin etal.,/. Biol. Chem. 2005, 280, 33895]. 

We adopted the prismatic layer of a bivalve shell as a model for in vitro repairing (Fig. 28). °° The prismatic layer is comprised of calcite prisms elongated in the c axis and an interprismatic organic framework. In the original prismatic layer, calcite polygonal columns 10-50 pm in diameter... 

In Akkin et al, a polarization-sensitive low coherence fiber interferometer was used to measure -0.5 nm, 1 ms displacements in crayfish leg nerves. Calcite prisms are used to compensate for optical path delay between the nerve reflection and a reference cover glass. The authors suggested that the technology may allow noninvasive detection of various neuropathies. 

Figure 11.5. Three examples showing different Habitus of later-grown calcite crystals preferentially nucleated on the edges and corners of earlier-formed calcite crystal. Changes in Habitus depending on crystallization stages or growth temperatures are indicated [3]. (a) Earlier-formed hexagonal prism (A) and later-formed scalenohedral crystal (B). (b) Earlier-formed hexagonal prism (b) and later-formed thicker crystal (a), (c) The shaded area shows an earlier-formed rhombohedral crystal, and the remaining area represents later-formed scalenohedral crystals.

When light is passed through a polarizer such as a calcite Nicol prism, the electric vector is parallel to the plane of polarization. The electric vector transforms in different ways when the polarized light is transmitted through a single crystal of a mineral, depending on its crystal symmetry. 

Hexagonal Four axes three in a plane at 60 degrees to each other, and one through the intersection of those axes Prism, pyramid, rhombohedron Quartz, beryl, tourmaline, calcite... 

Elmer Photoelectric Polarimeter, Model 141. Optical rotatory dispersion measurements were made either with the Perkin-Elmer instrument equipped with a Bausch and Lomb High Intensity Grating Monochromator, or with a manual spectropolarimeter constructed by Kirschner and co-workers (1) at Wayne State University. This instrument has been modified by replacing the calcite polarizing and analyzing prisms with quartz prisms and changing light source to a 500-watt Hanovia Xenon Arc Lamp. 

Crossed Nicol prisms An arrangement of two materials (calcite polarizing prisms or Polaroid discs) such that the first, the polarizer, transmits plane-polarized light that passes through the second, the analyzer, only if oriented in specific ways. 

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