AAD

AAD may refer to:

Aviation

Organizations

Medicine

People

Science and technology

ʿĀd

‘Ad (Arabic: عاد‎, ʿĀd) was an ancient tribe mentioned frequently in the Qur'an. ‘Ad is usually placed in the south of Arabia, in a location referred to as al-Ahqaf. The tribe's members, referred to as ‘Adites, formed a prosperous nation until destroyed in a violent storm after they had rejected the divine message preached by Hud. ‘Ad is regarded as one of the original Arab tribes, the "lost Arabs".

Legend

In local folklore, Hud and the tribe of ‘Ad have been linked to a legendary king ‘Ad, who ruled over a region whose capital was in "Wūbar".

Ontology of Quran

Aad are referred to in verse (11:60) of chapter (11) sūrat hūd (Hud): The verses related to this concept in the Quran (eg (7:65:2) refers to the second word of sura 7:65). There are 24 occurrences of concept of Aad in the Quran, namely (7:65:2)(7:74:7)(9:70:9)(11:50:2)(11:59:2)(11:60:10)(11:60:15) (14:9:9)(22:42:8)(25:38:1)(26:123:2)(29:38:1)(38:12:5)(40:31:5)(41:13:8)(41:15:2)(46:21:3) (50:13:1)(51:41:2)(53:50:3)(54:18:2)(69:4:3)(69:6:2)(89:6:6)

7-Aminoactinomycin D

7-Aminoactinomycin D (7-AAD) is a fluorescent chemical compound with a strong affinity for DNA. It is used as a fluorescent marker for DNA in fluorescence microscopy and flow cytometry. It intercalates in double-stranded DNA, with a high affinity for GC-rich regions, making it useful for chromosome banding studies.

Applications

With an absorption maximum at 546 nm, 7-AAD is efficiently excited using a 543 nm helium–neon laser; it can also be excited with somewhat lower efficiency using a 488 nm or 514 nm argon laser lines. Its emission has a very large Stokes shift with a maximum in the deep red: 647 nm. 7-AAD is therefore compatible with most blue and green fluorophores – and even many red fluorophores – in multicolour applications.

7-AAD does not readily pass through intact cell membranes; if it is to be used as a stain for imaging DNA fluorescence, the cell membrane must be permeabilized or disrupted. This method can be used in combination with formaldehyde fixation of samples.

Iwan

An iwan (Persian: ایوان eyvān, Arabic: إيوان‎ Iwan, also spelled ivan, Turkish: eyvan) is a rectangular hall or space, usually vaulted, walled on three sides, with one end entirely open. The formal gateway to the iwan is called pishtaq, a Persian term for a portal projecting from the facade of a building, usually decorated with calligraphy bands, glazed tilework, and geometric designs. Since the definition allows for some interpretation, the overall forms and characteristics can vary greatly in terms of scale, material, or decoration. Iwans are most commonly associated with Islamic architecture; however, the form was invented much earlier and fully developed in Mesopotamia, around the third century CE during the Parthian period.

Etymology

The root for this term is Old Persian 'apadana' (see Apadana palace at Persepolis) where king Darius I declares in an inscription, "I Darius,........ had this 'apadana' constructed.." This is a name given to this particular palace in modern literature, although the name simply implies a type of structure—the iwan, not a particular palace. The term in Old Persian stand for "unprotected" (a-pâd-ana), since the design allows for the structure to be open to the elements on one side, whence the term. At Persepolis, however, the 'apadana' takes the form of a veranda, where instead of a vaulted hall, there is a flat roof held up by columns—but still, open to the elements on only one side. A comparable structure would be found 2000 years later in Isfahan at the Palace of Chehel Sotoun. By the time of the Parthian and the Sasanian dynasties, iwan had emerged as two types of structure: the old columned one, and a newer vaulted structure—both, however, carrying the same native name of apadana/iwan, because both types are "unprotected" (open on one side to the elements).

Iwan (name)

Iwan is a masculine given name and a surname.

It is a Welsh and Cornish name related to Ifan and derived from the Latin Johannes.

It is also found in Germanic and Slavic languages as a variant of Ivan (name), which is a form of the Biblical name John. The Welsh given name related to this is Ioan rather than Iwan.

People (given name)

Iwan (disambiguation)

Iwan is an element in Islamic architecture.

It may also refer to:

See also