Genotoxicity of dicrotophos, an organophosphorous pesticide, assessed with different assays in vitro.

Dicrotophos is a systemic insecticide with a wide range of applications. We investigated the genotoxicity of dicrotophos using the Ames test, the chromosome aberration test in CHO-K1 cells, and the comet assay in the Hep G2 cells, while this chemicals' toxicity to both the cell lines was evaluated with the MTT assay. Results showed that dicrotophos did not show any cytotoxicity to CHO-K1 cells, whereas it was cytotoxic to HepG2 cells incubated for 24 h but not for 2 h. For genotoxicity of dicrotophos, a significant change in the numbers of bacterial reveratnts using Salmomella typhimurium TA97a, TA98, TA100, TA102, and TA1535 as the tester strains, an increase in the frequencies of chromosome aberration in CHO-K1 cells, and an induced DNA damage in HepG2 cells were observed, indicating that dicrotophos was genotoxic in these three performed assays. From this study, we provide further evidence towards of genotoxic effects of dicrotophos.

Fenthion and terbufos induce DNA damage, the expression of tumor-related genes, and apoptosis in HEPG2 cells.

This study investigates the effects of fenthion and terbufos, two organophosphorous pesticides, on DNA damage, tumor-related gene expression, and apoptosis in HepG2 cells. We found that exposure to concentrations ranging from 50 to 200 µM of fenthion and terbufos for 2 hr caused significant death in HepG2 cells. Both compounds induced DNA damage in a concentration-dependent manner as measured using the alkaline comet assay. Tumor-related genes (jun, myc, and fos) and apoptosis-related genes (socs3, tnfaip3, ppp1r15a, and nr4a1) were up-regulated by both compounds. Finally, both compounds induced apoptosis. The results demonstrate that both terbufos and fenthion induce DNA damage and should be considered potentially hazardous to humans.

Study of electrical characterization of 2-methyl-9, 10-di(2-naphthyl)anthracene doped with tungsten oxide as hole-transport layer.

An efficient p-doped transport layer composed of an ambipolar material, 2-methyl-9,10-di(2-naphthyl)anthracene (MADN) and tungsten oxide (WO(3)) has been developed. The admittance spectroscopy studies show that the incorporation of WO(3) into MADN can greatly improve the hole injection and the conductivity of the device. Moreover, when this p-doped layer was incorporated in the tris(8-quinolinolato)aluminum-based device, it achieved a current efficiency of 4.0 cdA and a power efficiency of 2.4 lmW at 20 mAcm(2). This work paves the way to simplify the fabrication of future p-i-n organic light-emitting devices with a single common ambipolar MADN material.

Comparative investigations of genotoxic activity of five nitriles in the comet assay and the Ames test.

Two short-term assays, the modified Ames test and the comet assay, were carried out to evaluate the genotoxicity of five nitriles (acetonitrile, propionitrile, methacrylonitrile, butyronitrile, and benzonitrile). With the comet assay, all the nitriles studied were found to induce the genotoxicity in human lymphocytes and Hep G2 cells. Except for butyronitrile, the genotoxic potency in lymphocytes was more pronounced than that in Hep G2 cells, and the rank order of genotoxicity induced by these five nitriles in lymphocytes was different from that in Hep G2 cells, indicating that the pathways leading to genotoxicity in both types of cells were different. In the modified Ames test, no tested nitriles showed mutagenic activity on Salmonella typhimurium strain TA 98 and TA 100 with and without metabolic activation. Comparing the results obtained from both tests in this study, the comet assay seems to be more sensitive than the modified Ames test. Thus, the comet assay can be used to detect the genotoxicity of all nitriles.

An organic p-type dopant with high thermal stability for an organic semiconductor.

To overcome the thermal instability of a p-doped organic hole transporting layer using the state-of-the-art p-type dopant, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane, a potent electron accepter, 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, has been found to possess superior thermal stability and proved to be an excellent p-type dopant.

Efficient green coumarin dopants for organic light-emitting devices.

We have synthesized a new green fluorescent dopant C-545P having incorporated five strategically placed "methyl" steric spacers on the julolidyl ring system. C-545P has good thermal properties and photostability, and when fabricated as a dopant in an Alq(3)-hosted OLED device, it shows notable improvement in luminance efficiency and is more resistant to concentration quenching than C-545T, particularly in the doping concentration range between 1 and 2% v/v, while achieving comparable device stability. [structure: see text]