Search results for " effect"
showing 10 items of 7524 documents
A Compact SPICE Model for Organic TFTs and Applications to Logic Circuit Design
2016
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-…
RANDOMIZED TRIAL OF CYCLOSPORINE MICROEMULSION (NEORAL) VERSUS CONVENTIONAL CYCLOSPORINE IN LIVER TRANSPLANTATION
1998
Background. The new microemulsion formulation of cyclosporine (Neoral) has been developed in an effort to improve the reliability of drug absorption. The objectives of this study were to assess the efficacy, safety, and tolerability of Neoral compared to the original formulation (Sandimmun) in liver transplant recipients. Methods. In a double-blind, parallel group study conducted in 28 centers across Europe and the United States, patients receiving primary orthotopic liver allografts were randomized within 24 hr of transplantation, 198 to Neoral and 192 to Sandimmun. Patients with and without T-tube biliary drainage were included. Postoperatively, all patients also received intravenous (i.v…
Solvent-trap reaction of triazolinediones with simple alkenes: An experimental/theoretical study of thermodynamic and kinetic parameters This work is…
2015
The reaction of N-phenyltriazolinedione with simple alkyl-substituted alkenes in a series of simple alcohols as nucleophilic solvents affords two products: a solvent-addition product (trap) and the ene adduct. Herein we present different experimental data which allow the estimation of different kinetic parameters (ΔΔH ≠ene,trap and ΔΔS ≠ene,trap ). The values of those parameters are found to be lower with a longer nucleophile-solvent molecule. Solvent isotope effects are also estimated and found in favour of the heavier (and smaller) deuterated compounds. Results from competition experiments in equimolar binary mixtures of different alcohols as solvents also point to the prevalence of the s…
CF3: An Electron-Withdrawing Substituent for Aromatic Anion Acceptors? “Side-On” versus “On-Top” Binding of Halides
2016
The ability of multiple CF3 -substituted arenes to act as acceptors for anions is investigated. The results of quantum-chemical calculations show that a high degree of trifluoromethyl substitution at the aromatic ring results in a positive quadrupole moment. However, depending on the polarizability of the anion and on the substitution at the arene, three different modes of interaction, namely Meisenheimer complex, side-on hydrogen bonding, or anion-π interaction, can occur. Experimentally, the side-on as well as a η(2) -type π-complex are observed in the crystal, whereas in solution only side-on binding is found.
Oxygen binding and its allosteric control in hemoglobin of the primitive branchiopod crustacean Triops cancriformis
2007
Branchiopod crustaceans are endowed with extracellular, high-molecular-mass hemoglobins (Hbs), the functional and allosteric properties of which have largely remained obscure. The Hb of the phylogenetically ancient Triops cancriformis (Notostraca) revealed moderate oxygen affinity, cooperativity and pH dependence (Bohr effect) coefficients: P50 = 13.3 mmHg, n50 = 2.3, and ϕ = −0.18, at 20 °C and pH 7.44 in Tris buffer. The in vivo hemolymph pH was 7.52. Bivalent cations increased oxygen affinity, Mg2+ exerting a greater effect than Ca2+. Analysis of cooperative oxygen binding in terms of the nested Monod–Wyman–Changeux (MWC) model revealed an allosteric unit of four oxygen-binding sites and…
The Tropical Forest Ecosystem: Reviewing the Effects of Deforestation on Climate and Environment
1991
The rapid decline of tropical rain forests in the 1980s, particularly caused by man-made forest clearance for farmland and timber exploitation, is accompanied by adverse climatic and environmental effects. In particular, rainfall and temperature conditions are adversely changed, with lower rainfall and high-er temperatures. Through deforestation, the atmospheric emissions of CO2 are increased and thus the global greenhouse effect is being strengthened. Tropical deforestation also increases soil erosion, depending upon the type of ecosystem. It also can be seen that floods more often occur in cases of deforestation. An international “action programme” for the protection and preservation of t…
Global sensitivity of aviation NO<sub>x</sub> effects to the HNO<sub>3</sub>-forming channel …
2013
Abstract. The impact of a recently proposed HNO3-forming channel of the HO2 + NO reaction on atmospheric ozone, methane and their precursors is assessed with the aim to investigate its effects on aviation NOx induced radiative forcing. The first part of the study addresses the differences in stratospheric and tropospheric HOx-NOx chemistry in general, by comparing a global climate simulation without the above reaction to two simulations with different rate coefficient parameterizations for HO2 + NO → HNO3. A possible enhancement of the reaction by humidity, as found by a laboratory study, particularly reduces the oxidation capacity of the atmosphere, increasing methane lifetime significantl…
Coulomb blockade thermometry
1996
One dimensional arrays of normal metal tunnel junctions have been found to exhibit properties which are very suitable for primary and secondary thermometry in a lithographically adjustable temperature range which extends over about two decades. The thermometer is remarkably insensitive to nonuniformities in the actual pattern and to even strong magnetic fields. We also discuss the behaviour of this device at very low temperatures where the hot electron effect due to poor electron phonon coupling ultimately takes over and at very high temperatures where the finite tunnel barrier effects appear. Short arrays, and especially single tunnel junctions show interesting deviations from the universa…
Magnetic nanoparticles between electrodes of tunnel junction: anomalous tunnel conductance
2002
Abstract Magnetic particles of microscopic size can be created in the process of Ni, Fe and Co mechanically controllable break junctions fabrication and trapped between the electrodes by magnetic dipole forces. Tunneling between the protruding nanoparticle and the sample electrode shows clear distinctions from the usual junctions: heavy deviation of the current–distance I(z) dependence from the expected exponential behavior at electrode separations z below 4.0– 4.5 A and on numerous occasions a sudden jump-like decrease of the tunnel current at z≈1.5– 2.0 A . Possible mechanisms behind observed anomalies including the short-range magnetic exchange coupling are discussed.
Environmental and depositional controls on laminated freshwater carbonates: An example from the Roman aqueduct of Patara, Turkey
2013
Carbonate deposits in aqueducts are a new high-resolution data source for environmental changes during the time of the Roman Empire, notably in the fields of palaeoclimate and spring hydrology. In order to distinguish environmental effects from those related to depositional setting, laminated carbonate deposits were compared along the entire length of an ancient aqueduct channel at Patara, Turkey. The carbonate deposits, up to 80mm in thickness, are composed of lamina couplets up to 1mm thick of alternating porous microspar and dense, columnar sparite. The former formed in the dry, warm season and the latter in the wet, cool season. The presence of biofilms seems to play a role in the devel…