We present results of the electro-optical effect in 90° twisted nematic cells of pristine and doped liquid crystals under an applied dc voltage. The doped cells were fabricated with a minute addition of either buckminsterfullerene C60 or multiwalled carbon nanotubes (CNTs). Investigated were the switching behaviors as well as the hystereses and time evolutions of both the optical transmittance and electrical capacitance of the display samples. It is shown that doping with nanotubes can effectively reduce the dc driving voltage and improve the switching behavior.

The response times of rotational molecular orientation of neat and carbon-nanotube-doped nematic liquid crystals were acquired through the measurement of transient current induced by a direct-current step voltage and from optical transmission data. A model based on the dielectric displacement current was developed to describe the electric field dependence of the response and to yield a rotational viscosity that would decrease with increasing concentration of carbon nanotubes. Optical dynamic response also showed a reduced rotational viscosity, with the lightly doped cells exhibiting a faster relaxation process than that of the neat cell.

EZH2 plays an important role in stem cell renewal and maintenance by inducing gene silencing via its histone methyltransferase activity. Previously, we showed that EZH2 downregulation enhances neuron differentiation of human mesenchymal stem cells (hMSCs); however, the underlying mechanisms of EZH2-regulated neuron differentiation are still unclear. Here, we identify Smurf2 as the E3 ubiquitin ligase responsible for the polyubiquitination and proteasome-mediated degradation of EZH2, which is required for neuron differentiation. A ChIP-on-chip screen combined with gene microarray analysis revealed that PPARγ was the only gene involved in neuron differentiation with significant changes in both its modification and expression status during differentiation. Moreover, knocking down PPARγ prevented cells from undergoing efficient neuron differentiation. In animal model, rats implanted with intracerebral EZH2-knocked-down hMSCs or hMSCs plus treatment with PPARγ agonist (rosiglitazone) showed better improvement than those without EZH2 knockdown or rosiglitazone treatment after a stroke. Together, our results support Smurf2 as a regulator of EZH2 turnover to facilitate PPARγ expression, which is specifically required for neuron differentiation, providing a molecular mechanism for clinical applications in the neurodegenerative diseases.

In our previous study, intracerebral implantation of peripheral blood stem cells (PBSCs) improved functional outcome in rats with chronic cerebral infarction. Based on this finding, a randomized, single blind controlled study was conducted in 30 patients [PBSC group (n = 15) and control group (n = 15)] with middle cerebral artery infarction confirmed on a T2-weighted MRI 6 months to 5 years after a stroke. Only subjects with neurological deficits of intermediate severity based on the National Institute of Health Stroke Scale (NIHSS; range: 9-20) that had been stable for at least 3 months were enrolled. Those in the PBSC group received subcutaneous G-CSF injections (15 μg/kg/day) for 5 consecutive days, and then stereotaxic implantation of 3-8 × 10 6 CD34 + immunosorted PBSCs. All 30 patients completed the 12-month follow-up. No serious adverse events were noted during study period. Improvements in stroke scales (NIHSS, ESS, and EMS) and functional outcomes (mRS) from baseline to the end of the 12-month follow-up period were significantly greater in the PBSC than the control group. The fiber numbers asymmetry (FNA) scores based on diffusion tensor image (DTI) tractography were reduced in every PBSC-treated subject, but not in the control group. Reduction in the FNA scores correlated well with the improvement in NIHSS. Furthermore, a positive motor-evoked potential (MEP) response by transcranial magnetic stimulation (TMS) appeared in 9 of the 15 subjects in the PBSC group. This phase II study demonstrated that implantation of autologous CD34 + PBSC was safe, feasible, and effective in improving functional outcome.