Particulate counter electrode system for enhanced light harvesting in dye-sensitized solar cells

A particulate counter electrode with photo scattering and redox catalytic properties is applied to dye sensitized solar cells (DSSCs) in order to improve photo conversion efficiency and simplify the assembly process. Our particulate counter electrode acts as both a photo reflecting layer and a catalyst for reduction of electrolyte. The reflective and catalytic properties of the electrode are investigated through optical and electrochemical analysis, respectively. A short circuit current density enhancement is observed in the DSSCs without the need to add an additional reflecting layer to the electrode. This leads to a simplified assembly process. (C) 2013 Optical Society of Americ

Electrochemical Investigation of High-Performance Dye-Sensitized Solar Cells Based on Molybdenum for Preparation of Counter Electrode

In order to improve the photocurrent conversion efficiency of dye-sensitized solar cells (DSSCs), we studied an alternative conductor for the counter electrode and focused on molybdenum (Mo) instead of conventional fluorine-doped tin oxide (FTO). Because Mo has a similar work function to FTO for band alignment, better formability of platinum (Pt), and a low electric resistance, using a counter electrode made of Mo instead of FTO lead to the enhancement of the catalytic reaction of the redox couple, reduce the interior resistance of the DSSCs, and prevent energy-barrier formation. Using electrical measurements under a 1-sun condition (100 mW/cm(2), AM 1.5), we determined that the fill factor (FF) and photocurrent conversion efficiency (eta) of DSSCs with a Mo electrode were respectively improved by 7.75% and 5.59% with respect to those of DSSCs with an FTO electrode. Moreover, we have investigated the origin of the improved performance through surface morphology analyses such as scanning electron microscopy and electrochemical analyses including cyclic voltammetry and impedance spectroscopy

Lattice-patterned LC-polymer composites containing various nanoparticles as additives

In this study, we show the effect of various nanoparticle additives on phase separation behavior of a lattice-patterned liquid crystal [LC]-polymer composite system and on interfacial properties between the LC and polymer. Lattice-patterned LC-polymer composites were fabricated by exposing to UV light a mixture of a prepolymer, an LC, and SiO2 nanoparticles positioned under a patterned photomask. This resulted in the formation of an LC and prepolymer region through phase separation. We found that the incorporation of SiO2 nanoparticles significantly affected the electro-optical properties of the lattice-patterned LC-polymer composites. This effect is a fundamental characteristic of flexible displays. The electro-optical properties depend on the size and surface functional groups of the SiO2 nanoparticles. Compared with untreated pristine SiO2 nanoparticles, which adversely affect the performance of LC molecules surrounded by polymer walls, SiO2 nanoparticles with surface functional groups were found to improve the electro-optical properties of the lattice-patterned LC-polymer composites by increasing the quantity of SiO2 nanoparticles. The surface functional groups of the SiO2 nanoparticles were closely related to the distribution of SiO2 nanoparticles in the LC-polymer composites, and they influenced the electro-optical properties of the LC molecules. It is clear from our work that the introduction of nanoparticles into a lattice-patterned LC-polymer composite provides a method for controlling and improving the composite's electro-optical properties. This technique can be used to produce flexible substrates for various flexible electronic devices

Pixel-isolation liquid crystals formed by polarization-selective UV-curing of a prepolymer containing cinnamate oligomer

A pixel isolated liquid crystal display was fabricated by polarization-selective anisotropic photoreaction of a prepolymer containing a cinnamate oligomer. The cinnamate oligomer was mainly distributed on the surface region of a UV-cured polymer wall. Anisotropic photo-dimerization of cinnamate moiety was achieved by polarized UV exposure. It was found that the polymer walls containing cinnamate dimers formed by polarized UV exposure showed ordered orientation of LC molecules at the boundary of the polymer walls resulting in electro-optic performance improvement. © 2010 Optical Society of America.1

Growth of ultra-uniform graphene using a Ni/W bilayer metal catalyst

We investigated a bilayer catalyst system consisting of polycrystalline Ni and W films for growing mono-layer graphene over large areas. Highly uniform graphene was grown on Ni/W bilayer film with 100% coverage. The graphene grown on Ni/W bilayer film and transferred onto an insulating substrate exhibited average hole and electron mobilities of 727 and 340 cm(2)V(-1)s(-1), respectively. A probable growth mechanism is proposed based on X-ray diffractometry and transmission electron microscopy, which suggests that the reaction between diffused carbon and tungsten atoms results in formation of tungsten carbides. This reaction allows the control of carbon precipitation and prevents the growth of non-uniform multilayer graphene on the Ni surface; this has not been straightforwardly achieved before. These results could be of importance in better understanding mono-layer graphene growth, and suggest a facile fabrication route for electronic applications. (C) 2015 AIP Publishing LLCopen0

Endoscopic Ultrasound-Guided Drainage without Fluoroscopic Guidance for Extraluminal Complicated Cysts

Background. Endoscopic ultrasound- (EUS-) guided drainage is generally performed under fluoroscopic guidance. However, improvements in endoscopic and EUS techniques and experience have led to questions regarding the usefulness of fluoroscopy. This study aimed to retrospectively evaluate the safety and efficacy of EUS-guided drainage of extraluminal complicated cysts without fluoroscopic guidance. Methods. Patients who had undergone nonfluoroscopic EUS-guided drainage of extraluminal complicated cysts were enrolled. Drainage was performed via a transgastric, transduodenal, or transrectal approach. Single or double 7 Fr double pigtail stents were inserted. Results. Seventeen procedures were performed in 15 patients in peripancreatic fluid collections (n=13) and pelvic abscesses (n=4). The median lesion size was 7.1 cm (range: 2.8–13.0 cm), and the mean time spent per procedure was 26.2±9.8 minutes (range: 16–50 minutes). Endoscopic drainage was successful in 16 of 17 (94.1%) procedures. There were no complications. All patients experienced symptomatic improvement and revealed partial to complete resolution according to follow-up computed tomography findings. Two patients developed recurrent cysts that were drained during repeat procedures, with eventual complete resolution. Conclusion. EUS-guided drainage without fluoroscopic guidance is a technically feasible, safe, and effective procedure for the treatment of extraluminal complicated cysts

FBXW7-mediated ERK3 degradation regulates the proliferation of lung cancer cells

Extracellular signal-regulated kinase 3 (ERK3) is an atypical member of the mitogen-activated protein kinase (MAPK) family, members of which play essential roles in diverse cellular processes during carcinogenesis, including cell proliferation, differentiation, migration, and invasion. Unlike other MAPKs, ERK3 is an unstable protein with a short half-life. Although deubiquitination of ERK3 has been suggested to regulate the activity, its ubiquitination has not been described in the literature. Here, we report that FBXW7 (F-box and WD repeat domain-containing 7) acts as a ubiquitination E3 ligase for ERK3. Mammalian two-hybrid assay and immunoprecipitation results demonstrated that ERK3 is a novel binding partner of FBXW7. Furthermore, complex formation between ERK3 and the S-phase kinase-associated protein 1 (SKP1)-cullin 1-F-box protein (SCF) E3 ligase resulted in the destabilization of ERK3 via a ubiquitination-mediated proteasomal degradation pathway, and FBXW7 depletion restored ERK3 protein levels by inhibiting this ubiquitination. The interaction between ERK3 and FBXW7 was driven by binding between the C34D of ERK3, especially at Thr417 and Thr421, and the WD40 domain of FBXW7. A double mutant of ERK3 (Thr417 and Thr421 to alanine) abrogated FBXW7-mediated ubiquitination. Importantly, ERK3 knockdown inhibited the proliferation of lung cancer cells by regulating the G1/S-phase transition of the cell cycle. These results show that FBXW7-mediated ERK3 destabilization suppresses lung cancer cell proliferation in vitro

In vitro antioxidant and anti-adipogenic effects of slendesta, standard potato extracts containing 5% protease inhibitor II

Background: The objective of the present study is to observe the anti-adipogenic effects of Slendesta (SLD), a standard potato protein extracts containing 5% potato protease inhibitor II (PI2) on the 3T3-L1 preadipocytes which are able to differentiate into mature adipocytes and accumulate lipids, as an obesity model with cytotoxicity and antioxidant effects.Materials and Methods: The cytotoxicity of SLD was observed against 3T3-L1 preadipocyte cell line by MTT assay, and also antiadipogenic effects were observed through lipid accumulation assay during 3T3-L1 differentiation as comparing with N-Acetyl-Lcysteine (NAC). In addition, antioxidant effects of SLD were detected by free radical scavenging capacity and superoxide dismutase (SOD)-like activity as comparing with ascorbic acid.Results: The SLD showed obvious cytotoxicity against 3T3-L1 pre-adipocyte cell line at higher concentrations, from 1.5 mg/ml for 72 h treatment, and the cytotoxic IC50 of SLD after 24, 48 and 72 h treatment times were detected as 10.11 ± 0.67, 5.71 ± 0.37 and 5.34 ± 0.21 mg/ml, respectively. The SLD also concentration-dependently inhibited the lipid accumulations formatted during 3T3-L1 cell differentiations. The adipogenic specific genes including PPARγ, C/EBPα, C/EBPβ and leptin were found to be reduced in SLD and NAC-treated cells compared to control cells. Furthermore, the SLD effectively showed DPPH radical scavenging activity (IC50 = 161.98 ± 64.65 μg/ml) and SOD-like effects (IC50 = 284.54 ± 54.47 μg/ml), and the cellular ROS was significantly inhibited in the SLD-treated cells compared to control cells.Conclusion: The results suggest that SLD effectively inhibit the differentiations of 3T3-L1 preadipose cell probably through antioxidant activities and direct cytotoxicity in case of higher concentration, along with satiety effects mediated by increases of circulating cholecystokinin. These findings are considered as direct evidences that SLD may serve as a predictable functional ingredient for obesity as an alternative therapy.Key words: Slendesta, potato protease inhibitor II, 3T3-L1 cell, cytotoxicity, anti-adipogenic effects, antioxidant effects