Temple University

About: Temple University is a education organization based out in Philadelphia, Pennsylvania, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 32154 authors who have published 64375 publications receiving 2219828 citations.

STIM proteins: dynamic calcium signal transducers

Abstract: Stromal interaction molecule (STIM) proteins function in cells as dynamic coordinators of cellular calcium (Ca2+) signals Spanning the endoplasmic reticulum (ER) membrane, they sense tiny changes in the levels of Ca2+ stored within the ER lumen As ER Ca2+ is released to generate primary Ca2+ signals, STIM proteins undergo an intricate activation reaction and rapidly translocate into junctions formed between the ER and the plasma membrane There, STIM proteins tether and activate the highly Ca2+-selective Orai channels to mediate finely controlled Ca2+ signals and to homeostatically balance cellular Ca2+ Details are emerging on the remarkable organization within these STIM-induced junctional microdomains and the identification of new regulators and alternative target proteins for STIM

Modeling disorder in polymer aggregates: the optical spectroscopy of regioregular poly(3-hexylthiophene) thin films.

Abstract: Absorption and emission in polymer aggregates is studied theoretically, taking into account excitonic (intermolecular) coupling, exciton-phonon (EP) coupling, and disorder, all treated on equal footing within a generalized Holstein Hamiltonian with numerically generated eigenmodes and energies. The disorder is modeled as a Gaussian distribution of molecular transition frequency offsets of width sigma and spatial correlation length l(0). Both herringbone (HB) and lamellar aggregate morphologies are considered. The emission spectral line shape is shown to undergo marked changes in response to increasing disorder, with the intensity of the ac-polarized 0-0 emission peak generally increasing relative to the replica intensities (0-1,0-2,[ellipsis (horizontal)]) as sigma increases and/or as l(0) decreases. This is contrary to the behavior of the b-polarized component of the 0-0 intensity, which, in HB aggregates, decreases with increasing disorder. Comparisons are made to analogous trends in oligomer aggregates. Analytical results are obtained in the strong EP coupling regime appropriate for conjugated polymers while treating the disorder perturbatively. A method for uniquely determining sigma and l(0) from the emission and absorption spectra is presented. Applications are made to absorption and low-temperature emission in thin films of regioregular poly(3-hexylthiophene), with excellent agreement between theory and experiment obtained for a spatial correlation length of only 3-4 molecules.