/pdf/micro-total-analysis-systems-1-introduction-theory-and-27f7corp18.pdf

Micro Total Analysis Systems. 1. Introduction, Theory, and Technology

This paper describes the development of ISFETs in an historical setting, but is not limited to that. Based on the development regarding the theory, the technology, the instrumentation and the experience with many specific applications, also future projects are defined, such as concerning cell acidification, REFET biasing and a complete new range of FET sensors based on local pressure induction by (bio)chemical interaction with immobilised charged molecules (hydrogels). Also the present patent and market position is discussed. It is concluded that in the past 30 years the ISFET research and development made continuous progress on a regular base, but the practical applications stayed behind, especially concerning the dynamic use of ISFETs in combination with an integrated pH actuator. The newly proposed research projects may be good for an other 30 years.

/pdf/thirty-years-of-isfetology-what-happened-in-the-past-30-wuecoc6kyx.pdf

Thirty years of ISFETOLOGY: What happened in the past 30 years and what may happen in the next 30 years

Introduction to multi-layer feed-forward neural networks

Conventional approaches to chemical sensors have
traditionally made use of a “lock-and-key” design,
wherein a specific receptor is synthesized in order to
strongly and highly selectively bind the analyte of
interest.1-6 A related approach involves exploiting a
general physicochemical effect selectively toward a
single analyte, such as the use of the ionic effect in
the construction of a pH electrode. In the first
approach, selectivity is achieved through recognition
of the analyte at the receptor site, and in the second,
selectivity is achieved through the transduction
process in which the method of detection dictates
which species are sensed. Such approaches are appropriate
when a specific target compound is to be
identified in the presence of controlled backgrounds
and interferences. However, this type of approach
requires the synthesis of a separate, highly selective
sensor for each analyte to be detected. In addition,
this type of approach is not particularly useful for
analyzing, classifying, or assigning human value
judgments to the composition of complex vapor
mixtures such as perfumes, beers, foods, mixtures of
solvents, etc.

/pdf/cross-reactive-chemical-sensor-arrays-38dz1buu0b.pdf

Cross-reactive chemical sensor arrays.

A closed loop infusion system controls the rate that fluid is infused into the body of a user. The closed loop infusion system includes a sensor system, a controller, and a delivery system. The sensor system includes a sensor for monitoring a condition of the user. The sensor produces a sensor signal, which is representative of the condition of the user. The sensor signal is used to generate a controller input. The controller uses the controller input to generate commands to operate the delivery system. The delivery system infuses a liquid into the user at a rate dictated by the commands from the controller. Preferably, the sensor system monitors the glucose concentration in the body of the user, and the liquid infused by the delivery system into the body of the user includes insulin. The sensor system uses the sensor signal to generate a message that is sent to the delivery system. The message includes the information used to generate the controller input. The sensor may be a subcutaneous sensor in contact with interstitial fluid. Also, two or more sensors may be used by the sensor system.

Closed loop system for controlling insulin infusion

The open-circuit potential of an electrochemically grown iridium oxide film is measured and shows a pH sensitivity between −60 and −80 mV/pH. This sensitivity is found to depend on the state of oxidation of the iridium oxide film; for a higher state of oxidation (or more of the oxide in the high valence state), the sensitivity is also higher. This high sensitivity can be explained on the basis of the extra proton release as a result of the acidic character of the porous hydrous oxyhydroxide, in combination with the redox behaviour.

The response time to a pH step is measured and is found to depend mainly on the thickness of the oxide; it varies from 40 ms to 0.35 s due to the porous nature of the film.

Drift measurements show that an iridium oxide film in reduced state is slowly oxidized by dissolved oxygen, whereas a pre-oxidized film in a pH = 4.01 buffer solution in contact with air shows a long-term drift of <0.3 mV/h.

/pdf/ph-sensor-properties-of-electrochemically-grown-iridium-yztq5qm6kn.pdf

pH sensor properties of electrochemically grown iridium oxide

https://ris.utwente.nl/ws/files/6881142/Linden83membrane.pdf

MEMBRANE SEPARATION IN FLOW INJECTION ANALYSIS Gas Diffusion

Bootstrap methods can be used as an alternative for cross-validation in regression procedures such as principal component regression (PCR). Several bootstrap methods for the estimation of prediction errors and confidence intervals are presented. It is shown that bootstrap error estimates are consistent with cross-validation estimates but exhibit less variability. This makes it easier to select the correct number of latent variables in the model. Using bootstrap confidence intervals for the regression vectors, it is possible to select a subset of the original variables to include in the regression, yielding a more parsimonious model with smaller prediction errors. The methods are illustrated using PCR, but can be applied to all regression models yielding a vector or matrix of regression coefficients.

/pdf/bootstrapping-principal-component-regression-models-29caeu1qpl.pdf

Bootstrapping principal component regression models

https://ris.utwente.nl/ws/files/6434640/Bos90processing.pdf

Processing of signals from an ion-elective electrode array by a neural network

https://ris.utwente.nl/ws/files/6880738/Zollinger87computerized.pdf

Computerized conductometric determination of stability constants of complexes of crown ethers with alkali metal salts and with neutral molecules in polar solvents

W.E. van der Linden

Papers

pH sensor properties of electrochemically grown iridium oxide

MEMBRANE SEPARATION IN FLOW INJECTION ANALYSIS Gas Diffusion

Bootstrapping principal component regression models

Processing of signals from an ion-elective electrode array by a neural network

Computerized conductometric determination of stability constants of complexes of crown ethers with alkali metal salts and with neutral molecules in polar solvents