Rheological studies on liquid-crystal colloids prepared by dispersing spherical microparticles with homeotropic surface anchoring

<p>We report rheological studies on the liquid-crystal colloids prepared by dispersing silica microparticles with homeotropic surface anchoring in 8CB liquid crystal. In nematic colloids, a shear-thickening behaviour is observed in low shear rate region. The apparent yield stress of both the nematic and smectic-A (SmA) phases increases with increasing volume fraction of particles . The critical strain amplitude (, i.e., crossover of and ) in SmA colloids decreases significantly with increasing . The frequency-dependent storage modulus of SmA colloids show a power-law behaviour and the loss modulus exhibits a shallow minimum. The optical rheomicroscopy shows that the nematic colloids form a network structure which are stretched and broken at high shear rate. When the temperature is decreased to SmA phase, the networks collapse showing regions of high-density particles. The variation of storage modulus with indicates that the SmA colloids response is dominated by defects.</p

Synthesis and characterization of novel ABA-type azobenzene-containing tri-block copolymers from telechelic polystyrene

<div><p>The telechelic polystyrene (tPS) was used as a macro-reversible addition fragmentation chain transfer (RAFT) agent to prepare the ABA-type tri-block copolymers (TBCs), poly{4-[4-(11-acryloyloxyundecyloxy)phenylazo]benzonitrile}-<i>b</i>-polystyrene-<i>b</i>-poly{4-[4-(11-acryloyloxyundecyloxy)phenylazo]benzonitrile} [poly(AUPAB)-<i>b</i>-PS-<i>b</i>-poly(AUPAB)] with 4-[4-(11-acryloyloxyundecyloxy)phenylazo]benzonitrile (AUPAB) as a monomer by the RAFT polymerization process. The poly(AUPAB) was used as a reference to probe the role of polystyrene block in poly(AUPAB)-<i>b</i>-PS-<i>b</i>-poly(AUPAB) macromolecular chain. The TBCs were characterized by spectral techniques, thermal analysis, and polarizing optical microscopic studies and compared the results with individual blocks, poly(AUPAB), and tPS. The TBCs exhibited higher thermal stability and liquid crystal–isotropic phase transition peak temperature (<i>T</i>_LC-I), and glass transition temperature (<i>T</i>_g) values compared to the poly(AUPAB). TBC <i>T</i>_LC-I value was dependent on the AUPAB wt% in macromolecular chain. Furthermore, the acquired results by optical microscopy suggest that after incorporation of the polystyrene block in acrylate-based pendant azobenzene polymer chain resulted in lower domain size of focal conic texture, which is characteristic of smectic-A liquid crystalline phase compared to the homopolymer. The photophysical properties of the TBCs were similar to those of the poly(AUPAB). Microphase-separated nano-segregation was observed in annealed thin films of TBCs.</p></div

Synthesis and characterization of novel ABA-type azobenzene-containing tri-block copolymers from telechelic polystyrene

<div><p>The telechelic polystyrene (tPS) was used as a macro-reversible addition fragmentation chain transfer (RAFT) agent to prepare the ABA-type tri-block copolymers (TBCs), poly{4-[4-(11-acryloyloxyundecyloxy)phenylazo]benzonitrile}-<i>b</i>-polystyrene-<i>b</i>-poly{4-[4-(11-acryloyloxyundecyloxy)phenylazo]benzonitrile} [poly(AUPAB)-<i>b</i>-PS-<i>b</i>-poly(AUPAB)] with 4-[4-(11-acryloyloxyundecyloxy)phenylazo]benzonitrile (AUPAB) as a monomer by the RAFT polymerization process. The poly(AUPAB) was used as a reference to probe the role of polystyrene block in poly(AUPAB)-<i>b</i>-PS-<i>b</i>-poly(AUPAB) macromolecular chain. The TBCs were characterized by spectral techniques, thermal analysis, and polarizing optical microscopic studies and compared the results with individual blocks, poly(AUPAB), and tPS. The TBCs exhibited higher thermal stability and liquid crystal–isotropic phase transition peak temperature (<i>T</i>_LC-I), and glass transition temperature (<i>T</i>_g) values compared to the poly(AUPAB). TBC <i>T</i>_LC-I value was dependent on the AUPAB wt% in macromolecular chain. Furthermore, the acquired results by optical microscopy suggest that after incorporation of the polystyrene block in acrylate-based pendant azobenzene polymer chain resulted in lower domain size of focal conic texture, which is characteristic of smectic-A liquid crystalline phase compared to the homopolymer. The photophysical properties of the TBCs were similar to those of the poly(AUPAB). Microphase-separated nano-segregation was observed in annealed thin films of TBCs.</p></div

A, cell cycle arrest in GBM neurospheres with vismodegib treatment <i>in vitro</i> a) A49910, b), B0027, c) B0043, d) B0051 and e) M45481.

<p><b>B</b>, Number of apoptotic cells (annexin V positive) in GBM neurospheres treated either with DMSO or with 50 μM vismodegib.</p

Log scale distribution of GLI1 mRNA expression in a) already published MB cases, along with 1 new case of MB from our repository b) distribution of GLI1 mRNA expression (RNA-Seq data) of the TCGA-GBM sub-cohort (N = 149), c) distribution of GLI1 mRNA expression in NIBMG-GBM cases (N = 19), d) distribution of GLI1 mRNA expression in GBM patient-derived early passage neurospheres (N = 6) and e) comparison of median GLI1 mRNA expression levels of high-Hh-MB (N = 13), low-Hh-MB (N-44), NIBMG-GBM (N = 19) and GBM patient-derived neurospheres (N = 6).

<p>Log scale distribution of GLI1 mRNA expression in a) already published MB cases, along with 1 new case of MB from our repository b) distribution of GLI1 mRNA expression (RNA-Seq data) of the TCGA-GBM sub-cohort (N = 149), c) distribution of GLI1 mRNA expression in NIBMG-GBM cases (N = 19), d) distribution of GLI1 mRNA expression in GBM patient-derived early passage neurospheres (N = 6) and e) comparison of median GLI1 mRNA expression levels of high-Hh-MB (N = 13), low-Hh-MB (N-44), NIBMG-GBM (N = 19) and GBM patient-derived neurospheres (N = 6).</p

Heat map of correlation matrix for the expression of 11 canonical Hh-pathway component genes in TCGA-GBM (N = 149, significant cut-off |r|>0.17, MTC with FDR 0.1).

<p>Heat map of correlation matrix for the expression of 11 canonical Hh-pathway component genes in TCGA-GBM (N = 149, significant cut-off |r|>0.17, MTC with FDR 0.1).</p