A Compact SPICE Model for Organic TFTs and Applications to Logic Circuit Design

This work introduces a compact DC model developed for organic thin film transistors (OTFTs) and its SPICE implementation. The model relies on a modified version of the gradual channel approximation that takes into account the contact effects, occurring at nonohmic metal/organic semiconductor junctions, modeling them as reverse biased Schottky diodes. The model also comprises channel length modulation and scalability of drain current with respect to channel length. To show the suitability of the model, we used it to design an inverter and a ring oscillator circuit. Furthermore, an experimental validation of the OTFTs has been done at the level of the single device as well as with a discrete-component setup based on two OTFTs connected into an inverter configuration. The experimental tests were based on OTFTs that use small molecules in binder matrix as an active layer. The experimental data on the fabricated devices have been found in good agreement with SPICE simulation results, paving the way to the use of the model and the device for the design of OTFT-based integrated circuits.This work was supported in part by the MIUR by means of the national Program PON R&C 2007-2013 and in part by project “Elettronica su Plastica per Sistemi Smart disposable” PON02 00355 3416798

A Compact SPICE Model for Organic TFTs and Applications to Logic Circuit Design

This work introduces a compact DC model developed for organic thin film transistors (OTFTs) and its SPICE implementation. The model relies on a modified version of the gradual channel approximation that takes into account the contact effects, occurring at nonohmic metal/organic semiconductor junctions, modeling them as reverse biased Schottky diodes. The model also comprises channel length modulation and scalability of drain current with respect to channel length. To show the suitability of the model, we used it to design an inverter and a ring oscillator circuit. Furthermore, an experimental validation of the OTFTs has been done at the level of the single device as well as with a discrete-component setup based on two OTFTs connected into an inverter configuration. The experimental tests were based on OTFTs that use small molecules in binder matrix as an active layer. The experimental data on the fabricated devices have been found in good agreement with SPICE simulation results, paving the way to the use of the model and the device for the design of OTFT-based integrated circuits.This work was supported in part by the MIUR by means of the national Program PON R&C 2007-2013 and in part by project “Elettronica su Plastica per Sistemi Smart disposable” PON02 00355 3416798

Phenylalanine hydroxylase deficiency: diagnosis and management guideline.

Phenylalanine hydroxylase deficiency, traditionally known as phenylketonuria, results in the accumulation of phenylalanine in the blood of affected individuals and was the first inborn error of metabolism to be identified through population screening. Early identification and treatment prevent the most dramatic clinical sequelae of the disorder, but new neurodevelopmental and psychological problems have emerged in individuals treated from birth. The additional unanticipated recognition of a toxic effect of elevated maternal phenylalanine on fetal development has added to a general call in the field for treatment for life. Two major conferences sponsored by the National Institutes of Health held \u3e10 years apart reviewed the state of knowledge in the field of phenylalanine hydroxylase deficiency, but there are no generally accepted recommendations for therapy. The purpose of this guideline is to review the strength of the medical literature relative to the treatment of phenylalanine hydroxylase deficiency and to develop recommendations for diagnosis and therapy of this disorder. Evidence review from the original National Institutes of Health consensus conference and a recent update by the Agency for Healthcare Research and Quality was used to address key questions in the diagnosis and treatment of phenylalanine hydroxylase deficiency by a working group established by the American College of Medical Genetics and Genomics. The group met by phone and in person over the course of a year to review these reports, develop recommendations, and identify key gaps in our knowledge of this disorder. Above all, treatment of phenylalanine hydroxylase deficiency must be life long, with a goal of maintaining blood phenylalanine in the range of 120-360 µmol/l. Treatment has predominantly been dietary manipulation, and use of low protein and phenylalanine medical foods is likely to remain a major component of therapy for the immediate future. Pharmacotherapy for phenylalanine hydroxylase deficiency is in early stages with one approved medication (sapropterin, a derivative of the natural cofactor of phenylalanine hydroxylase) and others under development. Eventually, treatment of phenylalanine hydroxylase deficiency will be individualized with multiple medications and alternative medical foods available to tailor therapy. The primary goal of therapy should be to lower blood phenylalanine, and any interventions, including medications, or combination of therapies that help to achieve that goal in an individual, without other negative consequences, should be considered appropriate therapy. Significant evidence gaps remain in our understanding of the optimum therapies for phenylalanine hydroxylase deficiency, nonphenylalanine effects of these therapies, and long-term sequelae of even well-treated disease in children and adults

Amperometric hydrogen peroxide and cholesterol biosensors designed by using hierarchical curtailed silver flowers functionalized graphene and enzymes deposits

Novel flower-like silver particles with triangular plates as building block along with functionalized graphene (straggled sheets) and enzymes horseradish peroxidase (HRP) or cholesterol oxidase (ChOx), were obtained on graphite electrode by galvanostatic electrodeposition method. The morphology of the electrodeposits has been characterized using scanning electron microscopy and energy-dispersive analysis of X-ray. The resulting biosensors named Nf/(HRP-f-graphene-Ag)/Gr and Nf/(ChOx-f-graphene-Ag)/Gr were evaluated for electrochemical activity using cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry. Optimization of the interdependent experimental parameters such as pH and temperature were achieved and maintained constant throughout the experiments. An activation energy of 2.5 kJ mol -1 was obtained for Nf/(HRP-f-graphene-Ag)/Gr electrode while Nf/(ChOx-f-graphene-Ag)/Gr showed an activation energy of 2.06 and 3.12 kJ mol-1. Furthermore, the former electrode demonstrated a good linear range of 25 μM to 19.35 mM with rapid response time of 3 s and detection limit of 5 μM for hydrogen peroxide. Similarly, the Nf/(ChOx-f-graphene-Ag)/ Gr electrode revealed a linear range of 0.1-4.5 mM with rapid response time of 3 s and an excellent detection limit of 0.514 mM for cholesterol. Besides this, the Nf/(HRP-f-graphene-Ag)/Gr and Nf/(ChOx-f-graphene-Ag)/Gr electrodes displayed a Michaelis-Menten constant of 0.26 and 0.57 mM, respectively, suggesting high affinity and enzymatic activity. The enhanced performance of biosensors towards detection of substrate and rejection of interferents, provided an evidence for its high anti-interference ability. Additionally the biosensors exhibit long term storage stability and reproducibility with antifouling properties. © 2013 Springer-Verlag Berlin Heidelberg.