EF

EF or ef may refer to:

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Science

Efavirenz

Efavirenz (EFV), sold under the brand names Sustiva among others, is a non-nucleoside reverse transcriptase inhibitor (NNRTI). It is used as part of highly active antiretroviral therapy (HAART) for the treatment of a human immunodeficiency virus (HIV) type 1. For HIV infection that has not previously been treated, the United States Department of Health and Human Services Panel on Antiretroviral Guidelines currently recommends the use of efavirenz in combination with tenofovir/emtricitabine (Truvada) as one of the preferred NNRTI-based regimens in adults and adolescents. Efavirenz is also used in combination with other antiretroviral agents as part of an expanded postexposure prophylaxis regimen to reduce the risk of HIV infection in people exposed to a significant risk (e.g. needlestick injuries, certain types of unprotected sex etc.).

It is usually taken on an empty stomach at bedtime to reduce neurological and psychiatric adverse effects.

Efavirenz was combined with the HIV medications tenofovir and emtricitabine, all of which are reverse transcriptase inhibitors. This combination of three medications under the brand name Atripla, provides HAART in a single tablet taken once a day.

E2F4

Transcription factor E2F4 is a protein that in humans is encoded by the E2F4 gene.

Function

The protein encoded by this gene is a member of the E2F family of transcription factors. The E2F family plays a crucial role in the control of cell cycle and action of tumor suppressor proteins and is also a target of the transforming proteins of small DNA tumor viruses. This protein binds to all three of the tumor suppressor proteins pRB, p107 and p130, but with higher affinity to the last two. It plays an important role in the suppression of proliferation-associated genes, and its gene mutation and increased expression may be associated with human cancer.

Structure

The E2F proteins contain several evolutionally conserved domains found in most members of the family. These domains include a DNA binding domain, a dimerization domain which determines interaction with the differentiation regulated transcription factor proteins (DP), a transactivation domain enriched in acidic amino acids (Asp + Glu), and a tumor suppressor protein association domain which is embedded within the transactivation domain.

Atlas E/F

The Atlas E/F, also designated SB-1A was an American expendable launch system and sounding rocket built using parts of decommissioned SM-65 Atlas missiles. It was a member of the Atlas family of rockets.

The first stage was built using parts taken from decommissioned Atlas-E and Atlas-F missiles, with various solid propellant upper stages used, depending on the requirements of the payload. The Atlas E/F was also used without an upper stage for a series of re-entry vehicle tests. On a single launch, an RM-81 Agena liquid-propellant upper stage was used.

Variants

Atlas E/F

Thirty Atlas E/F rockets were launched without upper stages for ABRES and BMRS re-entry vehicle tests between 1965 and 1974. Three of these launches failed. Five ABRES launches were also conducted whilst the missiles were still operational, however these did not use the Atlas E/F configuration.

Atlas E/F-Agena

An RM-81 Agena upper stage was used on a former Atlas-F, to launch the Seasat-1 satellite on 27 June 1978. This was the final flight of the Atlas-Agena. Previous Atlas-Agena launches had used Atlas D or Atlas SLV-3 rockets as first stages. The final Atlas - Agena was used on Atlas E/F.