Raw image format

A camera raw image file contains minimally processed data from the image sensor of either a digital camera, image scanner, or motion picture film scanner. Raw files are named so because they are not yet processed and therefore are not ready to be printed or edited with a bitmap graphics editor. Normally, the image is processed by a raw converter in a wide-gamut internal colorspace where precise adjustments can be made before conversion to a "positive" file format such as TIFF or JPEG for storage, printing, or further manipulation, which often encodes the image in a device-dependent colorspace. There are dozens, if not hundreds, of raw formats in use by different models of digital equipment (like cameras or film scanners).

Rationale

Raw image files are sometimes called digital negatives, as they fulfill the same role as negatives in film photography: that is, the negative is not directly usable as an image, but has all of the information needed to create an image. Likewise, the process of converting a raw image file into a viewable format is sometimes called developing a raw image, by analogy with the film development process used to convert photographic film into viewable prints. The selection of the final choice of image rendering is part of the process of white balancing and color grading.

Decoy receptor 3

Decoy receptor 3 (Dcr3), also known as tumor necrosis factor receptor superfamily member 6B (TNFRSF6B), TR6 and M68, is a soluble protein of the tumor necrosis factor receptor superfamily which inhibits Fas ligand-induced apoptosis.

Discovery

Dcr3 was identified in 1998 by the search of genes with homology to the TNFR gene superfamily in expressed sequence tag (EST) database.

Structure

The open reading frame of TNFRSF6B encodes 300 amino acids with a 29-residue signal sequence and four tandem cystein-rich repeats. Two transcript variants encoding the same isoform, but differing in the 5' UTR, have been observed for this gene. Unlike most of the other members of TNFR superfamily, TNFRSF6 is a soluble protein which contains no transmembrane domain.

Function

This gene belongs to the tumor necrosis factor receptor superfamily. It acts as a decoy receptor that competes with death receptors for ligand binding. The encoded protein is postulated to play a regulatory role in suppressing FasL- and LIGHT-mediated cell death and T cell activation as well as to induce angiogenesis via neutralization of TL1A. Overexpression of this gene has been noted in various tumors e.g. gastrointestinal tract tumors, and it is located in a gene-rich cluster on chromosome 20, with other potentially tumor-related genes.

Dicer

Dicer, also known as endoribonuclease Dicer or helicase with RNase motif, is an enzyme that in humans is encoded by the DICER1 gene. Being part of the RNase III family, Dicer cleaves double-stranded RNA (dsRNA) and pre-microRNA (pre-miRNA) into short double-stranded RNA fragments called small interfering RNA and microRNA, respectively. These fragments are approximately 20-25 base pairs long with a two-base overhang on the 3' end. Dicer facilitates the activation of the RNA-induced silencing complex (RISC), which is essential for RNA interference. RISC has a catalytic component argonaute, which is an endonuclease capable of degrading messenger RNA (mRNA).

Discovery

Dicer was given its name in 2001 by Emily Bernstein, a graduate student in Greg Hannon's lab at Cold Spring Harbor Laboratory, who sought to discover the enzyme responsible for generating small RNA fragments from double-stranded RNA. Dicer's ability to generate ~22 nucleotide RNA fragments was discovered by separating it from the RISC enzyme complex after initiating the RNAi pathway with dsRNA transfection. This experiment showed that RISC was not responsible for generating the observable small nucleotide fragments. Subsequent experiments testing RNase III family enzymes abilities to create RNA fragments narrowed the search to Drosophila CG4792, now named Dicer.