The frequency dependent first hyperpolarizabilities βvec(−2ω;ω,ω) (second harmonic generation) of conjugated molecules are studied using the time-dependent Hartree–Fock theory with the inclusion of solvent effects treated with the self-consistent reaction field theory. Using the intermediate neglect of differential overlap model parametrized for spectra we obtain a plot of βvec(theory) vs βvec(expt) with a fitted slope of 1.07 when solvent effects are included and only 0.49 when the solvent effects are not included. The calculated dependence of βvec on the degree of conjugation for the (−OCH3,−NO2) series of molecules that we study is 2.1 compared to 2.2 obtained from experiment, and for the [−N(CH3)2,−NO2] series of molecules a calculated value of 1.9 is obtained compared to the 1.9 value obtained from experiment.

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Aim To investigate the effects of sodium butyrate (NaB) and lipopolysaccharide (LPS) on gingival epithelial barrier. Material and methods We cultured human primary gingival epithelial cells and investigated the effects of NaB and LPS on gingival epithelial barrier and involved mechanisms at in vitro and in vivo levels by immunostaining, confocal microscopy, field emission scanning electron microscopy (FE‐SEM), transmission electronic microscopy (TEM), transepithelial electrical resistance (TEER), FTIC‐dextran flux, flow cytometry, real‐time PCR and Western blot assays. Results Our results showed that NaB, rather than LPS, destroyed the epithelial barrier by breaking down cell–cell junctions and triggering gingival epithelial cell pyroptosis with characteristic morphological changes, including swollen cells, large bubbles, pore formation in the plasma membrane and subcellular organelles changes. The upregulated expression of pyroptosis‐related markers, caspase‐3 and gasdermin‐E (GSDME) contributed to this effect. Pyroptosis aroused by NaB is a pro‐inflammatory cell death. Pyroptotic cell death provoked inflammatory responses by upregulation of IL‐8 and MCP‐1, and releasing intracellular contents into the extracellular microenvironment after pyroptotic rupture of the plasma membrane. Conclusions Our new findings indicate that butyrate is a potent destructive factor of gingival epithelial barrier and pro‐inflammatory mediator, which shed a new light on our understanding of periodontitis initiation.

3-MA, 3-methyladenine; ANXA5, annexin A5; ATG, autophagy related; CA-5f, (3E,5E)-3-(3,4-dimethoxybenzylidene)-5-[(1H-indol-3-yl)methylene]-1-methylpiperidin-4-one; CQ, chloroquine; CTSB, cathepsin B; CTSD, cathepsin D; DMSO, dimethyl sulfoxide; DNM2, dynamin 2; EBSS, Earle's balanced salt solution; GFP, green fluorescent protein; HCQ, hydroxyl CQ; HEK293, human embryonic kidney 293; HUVEC, human umbilical vein endothelial cells; LAMP1, lysosomal associated membrane protein 1; LC-MS/MS, liquid chromatography coupled to tandem mass spectrometry; LDH, lactic acid dehydrogenase; LMO7, LIM domain 7; MAP1LC3B/LC3B, microtubule associated protein 1 light chain 3 beta; NAC, N-acetyl cysteine; MYO1E, myosin IE; NSCLC, non-small cell lung cancer; PARP1, poly(ADP-ribose) polymerase 1; PI, propidium iodide; RFP, red fluorescent protein; ROS, reactive oxygen species; SQSTM1, sequestosome 1; TUNEL, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling.