Ptah

In Egyptian mythology, Ptah (/pəˈtɑː/;Egyptian: ptḥ, probably vocalized as Pitaḥ in ancient Egyptian) is the demiurge of Memphis, god of craftsmen and architects. In the triad of Memphis, he is the spouse of Sekhmet and the father of Nefertum. He was also regarded as the father of the sage Imhotep.

Origin and symbolism

Ptah is the Creator god par excellence: He is considered the demiurge who existed before all other things, and by his willfulness, thought the world. It was first conceived by Thought, and realized by the Word: Ptah conceives the world by the thought of his heart and gives life through the magic of his Word. That which Ptah commanded was created, with which the constituents of nature, fauna, and flora, are contained. He also plays a role in the preservation of the world and the permanence of the royal function.

In the Twenty-Fifth Dynasty, the Nubian pharaoh Shabaka would transcribe on a stela known as the Shabaka Stone, an old theological document found in the archives of the library of the temple of the god at Memphis. This document has been known as the Memphite Theology, and shows the god Ptah, the god responsible for the creation of the universe by thought and by the word.

5011 Ptah

5011 Ptah, provisional designation 6743 P–L, is a rare-type, highly eccentric asteroid, classified as potentially hazardous object and Apollo asteroid, about 1.6 kilometers in diameter. It was discovered on 24 September 1960, by Dutch astronomers Ingrid and Cornelis van Houten at Leiden, on photographic plates taken by Dutch–American astronomer Tom Gehrels at Palomar.

The rare Q-type asteroid orbits the Sun at a distance of 0.8–2.5 AU once every 2 years and 1 month (764 days). Its orbit is tilted by 7 degrees to the plane of the ecliptic and shows an exceptionally high eccentricity of 0.50. The Collaborative Asteroid Lightcurve Link (CALL) assumes an albedo of 0.20. As a potentially hazardous asteroid, it has a short Earth minimum orbit intersection distance (MOID) of 0.025 AU. It passes within that distance of Earth 15 times between 1900 and 2100, most recently on 21 January 2007, at 29.6 Gm. The next time will be in 2027 at 28.6 Gm. In addition, the asteroid crosses the orbit of Mars and classifies as a Mars-crosser.

Phosphotungstic acid-haematoxylin stain

Phosphotungstic acid haematoxylin (PTAH) is a mix of haematoxylin with phosphotungstic acid, used in histology for staining.

It stains some tissue in contrasting colors in a way similar to haematoxylin and eosin stain, as phosphotungstic acid binds to tissue proteins. It is used to show gliosis in the central nervous system, tumours of skeletal muscles, and fibrin deposits in lesions. Muscle is stained blue-black to dark brown, connective tissue is pale orange-pink to brownish red, fibrin and neuroglia stain deep blue, coarse elastic fibers show as purple, and bone and cartilage obtain yellowish to brownish red color.

PTAH is ideal for demonstrating striated muscle fibers and mitochondria, often without a counterstain. As such, it is used to identify contraction bands, as seen in contraction band necrosis.

PTAH stains ependymomas while it does not stain choroid plexus papillomas, providing one means of differentiating these tumors.

This technique has been largely replaced by immunohistochemistry techniques.