antiparallel vectors.    From Wordnet, Princeton University. 

In most organisms, DNA is formed as a very long and very narrow double-helix formation of two DNA strands coiled around each other in a head-to-toe "antiparallel" orientation.    From Wordnik.com.  [Citizendium, the Citizens' Compendium - Recent changes [en]] Reference

July 30, 2009 at 8:39 am the kittehs reminds me two electrons with all quantum numbers same except the spin parallel and antiparallel.    From Wordnik.com.  [MIRROR KITTEH - Lolcats 'n' Funny Pictures of Cats - I Can Has Cheezburger?] Reference

When the double strand is separated, two antiparallel strands exist.    From Wordnik.com.  [Citizendium, the Citizens' Compendium - Recent changes [en]] Reference

If everything is OK, and the circuit being commanded carries only DC, an antiparallel.    From Wordnik.com. Reference

Because these bonds are asymmetric, this arrangement of DNA strands is called antiparallel.    From Wordnik.com.  [Citizendium, the Citizens' Compendium - Recent changes [en]] Reference

Therefore, the nuclear spin magnetic moment vector is either parallel or antiparallel to the nuclear spin angular momentum vector.    From Wordnik.com.  [Citizendium, the Citizens' Compendium - Recent changes [en]] Reference

DNA polymerases can only extend a DNA strand in a 5 'to 3' direction, so other mechanisms are needed to copy the asymetrical antiparallel strand of the double helix.    From Wordnik.com.  [Citizendium, the Citizens' Compendium - Recent changes [en]] Reference

E1 and E2 are thought to be class II fusion proteins because the putative fusion peptide is supposedly localized in an internal sequence linked by antiparallel β-sheets.    From Wordnik.com.  [PLoS ONE Alerts: New Articles] Reference

The model predicts that these electrons are close enough together that the unpaired electron spin states can undergo transition, at some frequency, from antiparallel to parallel spin states (singlet-triplet intersystem crossing).    From Wordnik.com.  [PLoS Biology: New Articles] Reference

Many DNA sequences in prokaryotes and eukaryotes (and more in plasmids and viruses) have overlapping genes which may both occur in the same direction, on the same strand (parallel) or in opposite directions, on opposite strands (antiparallel).    From Wordnik.com.  [Citizendium, the Citizens' Compendium - Recent changes [en]] Reference

Field sine-waves, introduced into a nonlinear dielectric medium in antiparallel and antiphased fashion (45).    From Wordnik.com.  [Chapter 4] Reference

In the other state, its spin is antiparallel.    From Wordnik.com.  [Starchild Omnibus]

N-terminal domain 1 comprises of 7 β-strands (β1: 29-32, β2: 55-59, β3: 82-88, β4: 124-126, β5: 131-133, β6: 137-147 and β7: 150-158) and 6 α-helices (α1: 13-20, α2: 39-48, α3: 95-114, α4: 173-176, α5: 183-203, α6: 206-215), while C-terminal domain 2 is a SH3 domain with 5 strands forming an antiparallel β-sheet (β8: 220-227, β9: 231-240, β10: 246-250, β11: 253-257 and β12: 261-264).    From Wordnik.com.  [PLoS ONE Alerts: New Articles] Reference