25,589 research outputs found
From conventional membrane electrodes to ion-sensitive field-effect transistors
The theory concerning conventional membrane electrodes is often used as a starting point for the theoretical description of the operation of an ion-sensitive field-effect transistor. Although this results in a useful description of the device, a better view of the principles, and consequently the possibilities, of the new ion-sensitive device may result if the analysis is carried out in more detail, especially with respect to measuring concepts. This is presented in the paper. A careful comparison between the operation of a conventional membrane electrode and the i.s.f.e.t. leads to a definite classification of different types of i.s.f.e.t.s. These types are illustrated with corresponding measurements. In addition, the most appropriate application for each type is mentioned
The influence of the pH on the electrolyte-SiO2-Si system studied by ion-sensitive fet measurements and quasi-static C-V measurements
The responses of ion-sensitive FETs (ISFETs) with thermally grown SiO2 gate regions and of electrolyte-SiO2-Si (EOS) structures to stepwise changes in the pH were studied.\ud
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In addition to a change in the boundary potential at the electrolyte-SiO2 interface which accounts for the observed initial response of ISFETs, a mechanism is also proposed in which one or other hydrogen-bearing species interacts with the surface states at the SiO2-Si interface.\ud
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This proposed mechanism is based on the observed time drift in the response of ISFETs and on the changes in the shape of the quasi-static C-V curves of the EOS structures
Universal Codes from Switching Strategies
We discuss algorithms for combining sequential prediction strategies, a task
which can be viewed as a natural generalisation of the concept of universal
coding. We describe a graphical language based on Hidden Markov Models for
defining prediction strategies, and we provide both existing and new models as
examples. The models include efficient, parameterless models for switching
between the input strategies over time, including a model for the case where
switches tend to occur in clusters, and finally a new model for the scenario
where the prediction strategies have a known relationship, and where jumps are
typically between strongly related ones. This last model is relevant for coding
time series data where parameter drift is expected. As theoretical ontributions
we introduce an interpolation construction that is useful in the development
and analysis of new algorithms, and we establish a new sophisticated lemma for
analysing the individual sequence regret of parameterised models
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Micro-RNA family that modulates fibrosis and uses thereof
The present invention relates to the identification of a microRNA family, designated miR-29a-c, that is a key regulator of fibrosis in cardiac tissue. The inventors show that members of the miR-29 family are down-regulated in the heart tissue in response to stress, and are up-regulated in heart tissue of mice that are resistant to both stress and fibrosis. Also provided are methods of modulating expression and activity of the miR-29 family of miRNAs as a treatment for fibrotic disease, including cardiac hypertrophy, skeletal muscle fibrosis other fibrosis related diseases and collagen loss-related disease.Board of Regents, University of Texas Syste
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Micro-RNAs of the miR-15 family modulate cardiomyocyte survival and cardiac repair
A family of microRNAs, called the miR-15 family, which includes miR-195, are shown to be up-regulated during pathological cardiac remodeling and repress the expression of mRNAs required for cell proliferation and survival, with consequent loss of cardiomyocytes. Strategies to block expression of the miR-15 family in the heart as a treatment for diverse cardiac disease are provided.Board of Regents, University of Texas Syste
Bochner integrals in ordered vector spaces
We present a natural way to cover an Archimedean directed ordered vector
space by Banach spaces and extend the notion of Bochner integrability to
functions with values in . The resulting set of integrable functions is an
Archimedean directed ordered vector space and the integral is an order
preserving map
Cruise report: Belgica 06/13 ; HERMES Belgica BIO, 23-29 June 2006, Cork (IE)-Zeebrugge (B), Gollum channels and Whittard Canyon
An investigation of the hydration properties of chemically vapour-deposited silicon dioxide films by means of ellipsometry
Time-dependent ellipsometric measurements were made of the water absoprtion in SiO2 films grown by chemical vapour deposition at low temperatures. These films were exposed to water vapour at different pressurures. We determined in the ellipsometric volume percentage of water in the oxide film from the changes in the ellipsometric parameters due to water absorption. We also obtained a diffusion coefficient of water of the order of 1.3 x 10-13 cm2 s-1. From the reversible changes in the ellipsometric parameters due to dehydration we conclude that the water is physically adsorbed
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