Topochemical [2 + 2] cycloaddition polymerization of methyl p-phenylenediacrylate and 2,5-distyrylpyridine in nanocrystals, prepared by the reprecipitation method, were investigated in comparison with those in bulk crystals. The bulk single crystals, larger than 1 mum in size, broke into microcrystals with variety of size and shape in the course of polymerization. Interestingly, however, these nanocrystals show single-crystal-to-single-crystal transformation.
In order to obtain polymers having high second order nonlinear optical (NLO) response, various novel polymers that contain polar dye molecules in side chains and diacetylenic groups in the main chains were synthesized, and their second order NLO properties were studied. Some of these polymers consisting of para‐benzoate and para‐cinnamate main chains, showed extremely high NLO coefficients, d33 of 200 ‐ 350 pm/V, and the corresponding meta polymers showed much inferior NLO coefficients. The polymers having aliphatic main chains had very little NLO response probably because of their low glass transition temperatures and flexibility of main chains. The high SHG responses of these polymers are attributed to their facile orientation of both chromophores and main chains. In the case of para‐polymers, the main chain orientation of alkoxybenzoate and cinnamate along the chromophore is thought to be a reason for their high NLO coefficients.
Background: IκB-ζ, a member of the IκB family of nuclear proteins that regulates transcription, can be induced by Toll-like receptor (TLR) signaling.Results: IκB-ζ deficiency in B cells reduced T cell-independent antibody response-1.Conclusion: IκB-ζ is a key regulator of TLR-mediated class switch recombination (CSR) in B cells.Significance: T cell-dependent and -independent antibody responses are regulated by different mechanisms.
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