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We report on low-voltage-operated polymer transistors with poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)]/poly(methyl methacrylate) (PMMA) blended films as a gate dielectric layer. Top-gate polymer transistors are fabricated by all-solution processes on poly(9,9-dioctylfuorene-co-bithiophene) (F8T2) as an active layer. Both the operating voltage and charge carrier mobility are improved using P(VDF-TrFE)/PMMA blended films as a dielectric layer and by optimization of the ratio of the composite. F8T2 transistors have a high field-effect mobility of 1×10−2 cm2/V s and a low operation gate voltage of less than 10 V. The operation voltage effectively decreases owing to the high permittivity of the P(VDF-TrFE)]/(PMMA) blended film (10.4–8.4). The hysteresis induced by the ferroelectric polymer effectively disappears with the addition of a small amount of amorphous PMMA (5 wt %).

Two prospectively studied patients with polycythemia vera (PV) whose platelet counts showed marked periodic fluctuation during treatment with hydroxyurea (HU) are reported. Cycle lengths in both were approximately 28 to 30 days. In one patient, the cyclic process was no longer evident when treatment with HU was withheld, and it reappeared on treatment rechallenge. Circulating thrombopoietin (TPO) levels fluctuated out of phase with the platelet count despite markedly reduced TPO-receptor (c-Mpl) expression in bone marrow megakaryocytes. These observations suggest that the cyclic phenomenon may be related to both a transient state of HU-induced depletion of megakaryocytes and a concentration-dependent mitigation by TPO of the HU effect on megakaryocytes and their precursors. It is conceivable that the affected patients harbor a megakaryocyte progenitor pool whose apoptotic activity is differently modulated by either HU or high concentrations of TPO.