Importance of molecular alignment for organic photovoltaic devices

We study the effect of molecular alignment on the performance of organic photovoltaic devices (OPV) by using two porphyrin molecules of etioporphyrin-I (HOX) and octaethylporphyrin (HOEP) with similar chemical structures. Due to the minor differences in their peripheral substituents, the two porphyrin molecules form crystalline films of different molecular alignment. This has been verified by broader and redshift in the UV-vis absorption spectra as well as the grazing incidence x-ray diffraction of the films. OPV devices fabricated with these films show different performance. Stronger π-π stacking of HOX molecules exhibited better charge transport and photovoltaic performance than that of HOEP molecules

Magnetoresistance in boron carbide junctions

Photoemission and electric transport properties of ferromagnet–insulator–ferromagnet junctions with boron carbide (C2B10) dielectric barrier are presented. Using a non-oxide barrier confidence avoids oxidation of the interfaces with the ferromagnetic layers. Photoemission confirms chemical abruptness of the interface. Magnetoresistance ratios reaching 50% are observed at low temperatures, and large nonlinearity in the current–voltage curves show that impurities in the junctions play a key role. © 2003 American Institute of Physics

Low temperature processed bilayer dielectrics for low-voltage flexible saturated load inverters

Saturated load inverters using low temperature processed bilayer n-octadecylphosphonic acid (ODPA)/Al2O3 dielectrics were fabricated on flexible polyethylene terephthalate substrates. The saturated load inverters, which enable simplified processing, could operate at supply voltage as low as –2 V and achieve a gain up to 23 at –5 V. The inverters on ODPA/Al2O3 exhibited better mechanical stability upon bending due to the existence of self-assembled monolayer ODPA, implying their potential application in low voltage inexpensive flexible electronics

EBNA1-targeted probe for the imaging and growth inhibition of tumours associated with the Epstein–Barr virus

Epstein–Barr nuclear antigen 1 (EBNA1), a dimeric oncoprotein of the Epstein–Barr virus (EBV), is essential for both viral-genome maintenance and the survival of infected cells. Despite EBNA1’s potential as a therapeutic target, tools for the direct monitoring of EBNA1 in vitro and in vivo are lacking. Here, we show that a peptide-based inhibitor that luminesces when bound to EBNA1 inside the nucleus of EBV+ cells can regulate EBNA1 homodimer formation and selectively inhibit the growth of EBV+ tumours of nasopharyngeal carcinoma cells (C666-1 and NPC43) and Burkitt’s lymphoma Raji cells. We also show that the peptide-based probe leads to 93% growth inhibition of EBV+ tumours in mice. Our findings support the hypothesis that selective inhibition of EBNA1 dimerization can be used to afford better EBV-related cancer differentiation, and highlight the potential application of the probe as a new generation of biotracers for investigating the fundamental biological function of EBNA1 and for exploring its application as a therapeutic target

Characterization of high-yield performance as affected by genotype and environment in rice*

We characterized yield-relevant characters and their variations over genotypes and environments (locations and years) by examining two rice varieties (9746 and Jinfeng) with high yield potential. 9746 and Jinfeng were planted in two locations of Shanghai, China, during 2005 and 2006. The results show that there was a large variation in grain yield between locations and years. The realization of high yield potential for the two types of rice was closely related to the improved sink size, such as more panicles per square meter or grains per panicle. Stem and leaf biomasses were mainly accumulated from tillering stage to heading stage, and showed slow decline during grain filling. Meanwhile, some photosynthetic characters including net photosynthesis rate (P n), leaf area index (LAI), specific leaf area (SLA), fluorescence parameter (maximum quantum yield of PSII, F v/F m), chlorophyll content (expressed as SPAD value), as well as nutrient (N, P, K) uptake were also measured to determine their variations over genotypes and environments and their relationships with grain yield. Although there were significant differences between years or locations for most measurements, SLA at tillering and heading stages, F v/F m and LAI at heading stage, stem biomass at heading and maturity stages, and leaf nitrogen concentration at tillering and heading stages remained little changed, indicating their possible applications as selectable characters in breeding programs. It was also found that stem nitrogen accumulation at tillering stage is one of the most important and stable traits for high yield formation