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The coplanar group members have a fairly rigid structure, with their two phenyl rings in the same plane. It renders their structure similar to polychlorinated dibenzo- p -dioxins (PCDDs) and polychlorinated dibenzofurans , and allows them to act like PCDDs, as an agonist of the aryl hydrocarbon receptor (AhR) in organisms.
Congener descriptors give a shorthand notation for geometry and substituent positions. The twelve congeners that display all four of the descriptors are referred to as being "dioxin-like", referring both to their toxicity and structural features which make them similar to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2378-TCDD). [1]
There are 209 PCB compounds. Analogously to PCDDs at least two lateral chlorines in each ring in positions 3,4, and/or 5 are needed for dioxin-like activity. Because the AH receptor requires a planar (flat) structure, only PCB congeners that can rotate freely along the C—C axis between the rings can attach the receptor.
Intermediate Data Format (IDF) files are used interoperate between electronic design automation (EDA) software and solid modeling mechanical computer-aided design (CAD) software. The format was devised by David Kehmeier at the Mentor Graphics Corporation.
For example, butane has three conformers relating to its two methyl (CH 3) groups: two gauche conformers, which have the methyls ±60° apart and are enantiomeric, and an anti conformer, where the four carbon centres are coplanar and the substituents are 180° apart (refer to free energy diagram of butane).
If you can read cursive, the National Archives would like a word. Or a few million. More than 200 years worth of U.S. documents need transcribing (or at least classifying) and the vast majority ...
Via fences are used to shield microstrip and stripline transmission lines, guard edges of printed circuit boards, shield functional circuit units from each other, and to form the walls of waveguides integrated into a planar format. Via fences are cheap and easy to implement, but use up board space and are not as effective as solid metal walls.
The Troubled-Teen Industry Has Been A Disaster For Decades. It's Still Not Fixed.