Androgen-dependent mammary carcinogenesis in rats transgenic for the Neu proto-oncogene

AbstractTransgenic rats were created with overexpression of the Neu proto-oncogene in the mammary gland of both sexes, yet only males developed mammary cancer in an androgen-dependent fashion. Transgenic females only developed mammary cancer if treated with androgens. These tumors were positive for androgen receptor (AR), but negative for estrogen and progesterone receptors. Extensive analysis failed to detect mutations anywhere within the neu transgene from mammary carcinomas. Established mammary carcinomas eventually escaped their dependency on androgens. Transgenic long-term gonadectomized rats did not develop mammary cancer, but Neu overexpression stimulated the growth of their mammary glands. Our results suggest crosstalk between the Neu proto-oncogene and AR signaling pathways in the growth of both the normal and cancerous mammary epithelium

Ambipolar organic field-effect transistors fabricated using a composite of semiconducting polymer and soluble fullerene

Organic field-effect transistors (FETs) with equivalent hole and electron mobilities have been demonstrated. The devices were fabricated using a phase separated mixture of regioregular poly(3-hexylthiophene) and [6,6]-phenyl C-61-butyric acid methyl ester as the active layer and using aluminum (Al) for the source and drain electrodes. Measurements of the source-drain current versus gate voltage gave an electron mobility of mu(e)=2.0x10(-3) cm(2)/V s and hole mobility of mu(h)=1.7x10(-3)cm(2)/V s. The ambipolar FET properties arise from the use of Al electrodes for the source and drain; the contacts between the Al electrodes and the active layer are improved by thermal annealing at elevated temperatures (150 degrees C), thereby enabling balanced injection for both holes and electrons in a single device.open413

Photovoltaic effects on the organic ambipolar field-effect transistors

An organic multifunctional device, which can function as an ambipolar field-effect transistor (FET) and a photovoltaic (PV) cell, has been demonstrated using a phase separated mixture of poly(3-hexylthiophene) and [6,6]-phenyl C-61-butyric acid methyl ester. The gold (Au) electrode used for hole injection in the FET mode (source) acts as the anode in PV cell mode, and the aluminum (Al) electrode for electron injection in the FET mode (drain) acts as the cathode in PV cell mode. The device exhibits clear PV phenomena under illumination at zero gate bias with a power conversion efficiency of 0.6% as well as the properties of an ambipolar FET when the gate bias is applied.open292

Electroluminescence in polymer-fullerene photovoltaic cells

We report electroluminescence (EL) in photovoltaic (PV) cells based on semiconducting polymer-fullerene composites. By applying a forward bias to the PV cells, the devices exhibited a clear EL action with a peak around 1.5 eV. We ascribe this peak to an "electric field-assisted exciplex" formed between the electrons in the fullerenes and the holes in the polymers, thereby resulting in radiative recombination in the composites. This finding is totally unexpected because of a strong photoluminescence quenching in the same materials. Since the same devices also showed typical photovoltaic effects under illumination, our results demonstrate a dual functionality in one device; polymer photovoltaic cells and polymer light-emitting diodes.open464

Multilayer bipolar field-effect transistors

Field-effect transistors comprising a layer of regioregular poly(3-hexylthiophene) (rr-P3HT) separated from a parallel layer of the soluble fullerene,[6,6]-phenyl C-61-butyric acid methyl ester (PCBM) by a layer of titanium suboxide (TiOx), are fabricated by solution processing. Because the TiOx is an electron transporting material and a hole blocking material, this multilayer architecture operates either in the p-channel mode with holes in the rr-P3HT layer or in the n-channel mode with electrons in the PCBM layer.open201