Advanced Systems Format

Advanced Systems Format (formerly Advanced Streaming Format, Active Streaming Format) is Microsoft's proprietary digital audio/digital video container format, especially meant for streaming media. ASF is part of the Media Foundation framework.

Overview and features

ASF is based on serialized objects which are essentially byte sequences identified by a GUID marker.

The format does not specify how (i.e. with which codec) the video or audio should be encoded; it just specifies the structure of the video/audio stream. This is similar to the function performed by the QuickTime, AVI, or Ogg container formats. One of the objectives of ASF was to support playback from digital media servers, HTTP servers, and local storage devices such as hard disk drives.

The most common media contained within an ASF file are Windows Media Audio (WMA) and Windows Media Video (WMV). The most common file extensions for ASF files are extension .WMA (audio-only files using Windows Media Audio, with MIME-type audio/x-ms-wma) and .WMV (files containing video, using the Windows Media Audio and Video codecs, with MIME-type video/x-ms-asf). These files are identical to the old .ASF files but for their extension and MIME-type. The different extensions are used to make it easier to identify the content of a media file.

Methylestradiol

Methylestradiol, or 17α-methylestradiol (17α-ME), is a semisynthetic, steroidal estrogen that has been sold in combination with normethandrone (methylestrenolone) under brand names including Ginecosid, Ginecoside, Mediol, Renodiol for the treatment of menopausal symptoms in Brazil, Venezuela, and Indonesia. Due to the presence of the 17α-methyl group, methylestradiol cannot be deactivated by oxidation of the 17β-hydroxy group, resulting in improved metabolic stability and potency relative to estradiol analogously to ethinyl estradiol (17α-ethinylestradiol). In addition to its clinical use, methylestradiol has been studied as a radiopharmaceutical.

Methylestradiol is an active metabolite of the anabolic steroid methyltestosterone (17α-methyltestosterone), and is responsible for the estrogenic side effects of the drug such as gynecomastia.Metandienone (17α-methyl-δ¹-testosterone), another anabolic steroid, produces a similar but non-identical estrogenic metabolite.

See also

4-Methylcathinone

4-Methylcathinone (also known as Nor-Mephedrone, 4-MC and NSC-60487), is a stimulant drug of the cathinone chemical class that has been sold online as a designer drug. It is a metabolite of the better known drug mephedrone (4-methylmethcathinone).

4-Methylcathinone displays a 2.4-fold selectivity to promote monoamine release via DAT over SERT as opposed to 309-fold selectivity for cathinone.

See also

References