Diene groups in the terminal position of the lipid acyl chains undergo an irreversible cis f trans isomerization when lipid films are incubated on a solid support under an atmosphere which is adjusted to a relative humidity (RH) in the range 20% < RH < 100%. In general, isomerization and polymerization can be modulated by RH, temperature, and the phase state of the lipid. Under nearly dry condi...

Most vertebrate retinas contain a single type of rod for scotopic vision and multiple types of cones for photopic and color vision. The retinas of certain amphibian species uniquely contain two types of rods: red rods, which express rhodopsin, and green rods, which express a blue-sensitive cone pigment (M1/SWS2 group). Spontaneous activation of rhodopsin induced by thermal isomerization of the ...

Phytochromes are red-light photoreceptor proteins that regulate a variety of responses and cellular processes in plants, bacteria, and fungi. The phytochrome light activation mechanism involves isomerization around the C15 horizontal lineC16 double bond of an open-chain tetrapyrrole chromophore, resulting in a flip of its D-ring. In an important new development, bacteriophytochrome (Bph) has be...

We investigate the isomerization enthalpy of the Dihydroazulene/Vinylheptafulvene (DHA/VHF) molecular photoswitch system derivatives using electronic structure calculation methods including Density Functional Theory (DFT), Quantum Monte Carlo (QMC) and Coupled Cluster (CCSD(T)). Recent efforts have focused on tuning the isomerization enthalpy of the photoswitch for solar thermal energy storage ...

5-(Hydroxymethyl)furfural (HMF) and levulinic acid production from glucose in a cascade of reactions using a Lewis acid (CrCl3) catalyst together with a Brønsted acid (HCl) catalyst in aqueous media is investigated. It is shown that CrCl3 is an active Lewis acid catalyst in glucose isomerization to fructose, and the combined Lewis and Brønsted acid catalysts perform the isomerization and dehydr...

We have studied the kinetics of trans to cis isomerization under the illumination of ultraviolet light, in the Langmuir monolayer of mesogenic azobenzene dimer, bis-[5-( 4' -n-dodecyloxy benzoyloxy)-2-( 4''-methylphenylazo)phenyl] adipate, at an air-water interface. We find that the trans to cis isomerization reaction of the molecules in the monolayer shows deviation from the first-order kineti...

In view of the possible role of electron transfer in biology and medicine, and wide distribution of polyenes in living nature, we consider the electron transfer mechanism of geometrical cis-trans isomerization as an important route which can play a key role in many photochemical and biological processes. The various mechanisms of geometrical cis-trans isomerization mediated by electron transfer...

The isomerization of spiropyrans in crystals was realized under high pressure, and the corresponding mechanochromic response could be observed by the naked eye. In situ UV-Vis spectroscopy study demonstrated that the equilibrium constant increases with the increasing pressure, from which we proposed that the negative volume of reaction determined the isomerization under high pressure.

Iridium complexes of novel NCP pincer ligands containing pyridine and phosphinite arms have been synthesized. One Ir complex shows good catalytic activity for alkane dehydrogenation, and all complexes are highly active for olefin isomerization. A combination of the Ir complex and a (PNN)Fe pincer complex catalyzes the formation of linear alkylboronates selectively from internal olefins via sequ...

Product inhibition in mechanisms in which the free enzyme isomerizes In any enzyme mechanism, the form of free enzyme left after the last product has been released may be different from the one to which the first substrate binds, so that the catalytic cycle is completed by an enzyme isomerization to regenerate the original form. Efforts to detect such isomerization met with little success, howe...