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As part of continuing efforts to deepen the understanding of photo-induced mass transport in azo-containing polymers, we compared the diffraction efficiency (DE) during surface-relief grating (SRG) inscription, photo-induced molecular orientation (< P 2 >), and thermal stability in two sets of supramolecular azopolymer complexes, namely, hydrogen-bonded (H-bonded) and ionically bonded (i-bonded) complexes, both as a function of the polymer degree of polymerization (DP). To that end, poly(4-vinylpyridine) (P4VP) polymers with DPs of 41, 480, and 1900 were H-bonded at an equimolar ratio with 4-hydroxy-4'-dimethylaminoazobenzene (azoOH), and the fully quaternized derivatives of the three P4VPs (P4VPMe) were i-bonded via ion exchange to sodium 4-[(4-dimethylamino)-phenylazo]benzene sulfonate (azoSO 3 ), also known as methyl orange, where the OH functionality of azoOH is replaced by a sulfonate group. The i-bonded complexes show much better DE performances and < P 2 > levels than those of H-bonded complexes, which we relate to the liquid crystal structure of the former complexes. Fitting the < P 2 > curves by a biexponential equation leads to two parameters associated with a fast trans-cis or angular hole burning (AHB) process and a slow angular redistribution (AR) process of the azo, respectively. It is found that AHB is predominant in the H-bonded complexes, whereas the AR contribution is much greater in the i-bonded complexes, assuring their superior SRG efficiency that is enabled by the anisotropic free volume created mainly by the AR process. In each set of complexes, the SRG efficiency is much better for the lowest DP complex, while the AR contribution is constant (and low) for the H-bonded complexes and increases roughly linearly with the decrease in DP for the i-bonded complexes. The latter difference might be related to the presence of entanglements in the complexes with DPs 480 and 1900, which slow down the macroscopic movement during SRG inscription but not the molecular-scale movement in photo-orientation.

Bletilla striata is widely used for stanching bleeding. In this study, polysaccharides from B. striata (BSP) were extracted by hot water. Four polysaccharides named BSP-1-BSP-4 were fractionated using DEAE-52 cellulose. BSP fractions contained sulfate, and the degrees of substitution of BSP-3 and BSP-4 were 1.59 and 1.70, respectively. Analysis of monosaccharide composition showed that four polysaccharides were mainly composed of mannan and glucose. The in vitro results showed that BSP-1-BSP-4 elicited pro-coagulant capacities by shortening the activating partial thromboplastin time, prothrombin time, and thrombin time and elevating the fibrinogen content. Immunomodulatory activity was evaluated by MTT assay, the pinocytic capacity and NO production. Although BSP fractions did not affect RAW 264.7 cell viability, they, especially BSP-2, enhanced the immunomodulatory activity by increasing the pinocytic capacity and NO production. Overall, BSP may be developed as a potential coagulant with immunomodulatory effects., Competing Interests: The authors declare no competing financial interest., (© 2020 The Authors. Published by American Chemical Society.)

The c-KIT G-quadruplex structures are a novel class of attractive targets for the treatment of gastrointestinal stromal tumor (GIST). Herein, a series of new quinazolone derivatives with the expansion of unfused aromatic ring system were designed and synthesized. Subsequent biophysical studies demonstrated that the derivatives with adaptive scaffold could effectively bind to and stabilize c-KIT G-quadruplexes with good selectivity against duplex DNA. More importantly, these ligands further inhibited the transcription and expression of c-KIT gene and exhibited significant cytotoxicity on the GIST cell line HGC-27. Overall, these quinazolone derivatives represent a new class of promising c-KIT G-quadruplex ligands. The experimental results have also reinforced the idea of inhibition of c-KIT expression through targeting c-KIT G-quadruplex DNA.

The first set of experimentally determined C-NO bond homolytic and heterolytic dissociation enthalpies in solution is derived by using direct titration calorimetry combined with appropriate electrode potentials through thermodynamic cycles. The homolytic bond dissociation energy scale (BDEs) of the corresponding C-NO bonds in the gas phase was also calculated at the MP2/6-311+G**//B3LYP/6-31G* level and BP86/6-31G*//B3LYP/6-31G* level of theory for the purpose of comparison. The C-NO and S-NO bond thermodynamic parameters were used to predict the trend of NO transfer from C-nitroso substrates to thiols in acetonitrile solution.