392 research outputs found

    A new approach to immunoFET operation

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    A new method is presented for the detection of an immunological reaction taking place in a membrane, which covers the gate area of an ISFET. By stepwise changing the electrolyte concentration of the sample solution, a transient diffusion of ions through the membrane-protein layer occurs, resulting in a transient membrane potential, which is measured by the ISFET. The diffusion rate is determined by the immobile charge density in the amphoteric protein layer, which changes upon formation of antibody—antigen complexes. No membrane potential is induced at zero fixed charge density as occurs at a protein characteristic pH. Isoeletric points of embedded proteins can be determined by detecting the zero potential response.\ud \ud Up to now, the authors have studied the membrane adsorption of lysozyme, human serum albumin (HSA) and the immune reaction of HSA with the antibody anti-human serum albumin (αHSA). The influence of protein parameters on the amplitude of the transient can be described with an empirical equation. Assuming Langmuir behaviour, the protein concentration in the solution can well be correlated with the concentration in the membrane.\ud \ud This new detection method is unique concerning direct measurements of charge densities and isoelectric points of amphoteric macromolecules adsorbed in the membrane. The simple procedure of one incubation stage followed by one detection stage, without separate washing and labelling techniques, gives direct information about specific charge properties of the macromolecules to be studied

    Commercial production of tomatoes in Western Australia

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    The tomato crop is subject to many hazards. Pests, diseases and adverse environmental conditions are frequently encountered and must be overcome. This bulletin has been prepared to give growers, whether they be experienced or new to tomato culture, an outline of the more important cultural practices involved in producing satisfactory crops. Common diseases and pests are described and where possible recommendations for their control are given.https://researchlibrary.agric.wa.gov.au/bulletins3/1004/thumbnail.jp

    Development of diving capacity in emperor penguins

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    Development of diving capacity in emperor penguins

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    Evolution of Fe Species During the Synthesis of Over-Exchanged Fe/ZSM5 Obtained by Chemical Vapor Deposition of FeCl3

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    Abstract The evolution of iron in over-exchanged Fe/ZSM5 prepared via chemical vapor deposition of FeCl 3 was studied at each stage of the synthesis. Different characterization techniques (EXAFS, HR-XANES
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