4 research outputs found
A molecular communication channel consisting of a single reversible chain of hydrogen bonds in a conformationally flexible oligomer
Communication of information through the global switching of conformation in synthetic molecules has hitherto entailed the inversion of chirality. Here, we report a class of oligomer through which information may be communicated through a global reversal of polarity. Ethylene-bridged oligoureas are constitutionally symmetrical, conformationally flexible molecules organized by a single chain of hydrogen bonds running the full length of the oligomer. NMR reveals that this hydrogen-bonded chain may undergo a coherent reversal of directionality. The directional uniformity of the hydrogen-bond chain allows it to act as a channel for the spatial communication of information on a molecular scale. A binding site at the terminus of an oligomer detects local information about changes in pH or anion concentration and transmits that information—in the form of a directionality switch in the hydrogen-bond chain—to a remote polarity-sensitive fluorophore. This propagation of polarity-encoded information provides a new mechanism for molecular communication
On the Spontaneous CP Breaking at Finite Temperature in a Nonminimal Supersymmetric Standard Model
We study the spontaneous CP breaking at finite temperature in the Higgs
sector in the Minimal Supersymmetric Standard Model with a gauge singlet. We
consider the contribution of the standard model particles and that of stops,
charginos, neutralinos, charged and neutral Higgs boson to the one-loop
effective potential. Plasma effects for all bosons are also included. Assuming
CP conservation at zero temperature, so that experimental constraints coming
from, {\it e.g.}, the electric dipole moment of the neutron are avoided, and
the electroweak phase transition to be of the first order and proceeding via
bubble nucleation, we show that spontaneous CP breaking cannot occur inside the
bubble mainly due to large effects coming from the Higgs sector. However,
spontaneous CP breaking can be present in the region of interest for the
generation of the baryon asymmetry, namely inside the bubble wall. The
important presence of very tiny explicit CP violating phases is also commented.Comment: 28 pages, 4 figures available upon request, DFPD 94/TH/38 and SISSA
94/81-A preprint