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A compact model for the current–voltage characteristics of organic thin-film transistors (OTFTs), which includes the effects of the contact regions, is proposed. Different physical and morphological aspects of contacts with organic or other emerging materials such as graphene, semiconducting dichalcogenides such as MoS2, or NW devices are described. The electrical behavior of the contacts is studied in OTFTs, and circuit models that describe them are reviewed. Two trends are observed in the current–voltage curves of the contacts of different OTFTs: linear and nonlinear, and different models are used to explain them. A unified model for the contact region that reproduces both trends and gathers the different physical and structural features of the contacts is developed. It is described by a single parameter and introduced in a generic analytical model for TFTs. The variability in OTFT structures, materials, and fabrication approaches gives rise to a strong variability in the values of the parameters of the model. In this regard, a characterization technique to determine the value of the parameters of the model from experimental data is also developed. Different physical tests are proposed to validate the results of the technique. The procedure is applied to recent experimental data for different pentacene-based transistors. The good agreement between the experimental data and our analytical results provides a way to relate the parameters of the model with the physical or geometrical origin of the contact effects in OTFTs. [ABSTRACT FROM PUBLISHER]

Human liver cytochromes P-450 (P450) 2C9 and 2C10 expressed in yeast reproduce all the metabolic features of the oxidation of tienilic acid (2-aryloxo-thiophene) and its isomer (3-aroylthiophene) by human liver microsomes. Microsomes of yeast expressing either P450 2C9 or P450 2C10 catalyze (a) the 5-hydroxylation of tienilic acid by NADPH and O2 (Km = 6 µM, Vmax = 2.5 turnover/min), (b) the activation of tienilic acid and its isomer into electrophilic metabolites which covalently bind to proteins, and (c) the formation of a mercaptoethanol adduct which results from the trapping of the tienilic acid isomer sulfoxide by this thiol. Microsomes of yeast expressing human liver P450 3A4, 1A1 and 1A2 are unable to catalyze these reactions. There is a striking similarity between the quantitative characteristics of the oxidation of tienilic acid (and its isomer) by yeast-expressed P450 2C9 (or 2C10) and by human liver microsomes: (a) analogous Km values (around 10 µM) for tienilic acid 5-hydroxylation, (b) a strong inhibition of tienilic acid oxidation by human sera containing anti-(liver kidney microsomes type 2) (anti-LKM2 ) antibodies, and (c) almost identical relative ratios of tienilic acid metabolic activation/5-hydroxylation and of tienilic acid activation/the activation of its isomer with both systems. Rates of oxidation of tienilic acid (and its isomer) by yeast microsomes are 6-8 fold higher than those found in human liver microsomes, which would be in agreement with the previously reported amount of P450 2C9 in human liver. These results not only suggest the important role of P450 2C9 in the oxidative metabolism of tienilic acid in human liver, but also indicate that the 5-hydroxylation reaction could be a useful marker for P450 2C9 activity and underline the interest of human liver P450s expressed in yeast as tools for studying the formation of reactive metabolites. [ABSTRACT FROM AUTHOR]

An abstract of the paper "Is Useful the Visual Estimate of Transmurality of Hipoperfusión in Stress Cardiac Magnetic Resonance?," by Sanchez G. Juan Miguel and colleagues is presented.