Bulk density was determined ceritinib novartis by using standard 100 cm3 cylinders. For saturated hydraulic conductivity determination, the ��Constant Head Permeameter�� method [44] was used. The disturbed soil samples for the other analyses were dried, crumbled, and sieved in 2 mm sieve. Saturation extracts obtained from the sieved soil samples were used to measure EC, pH, and temperature by using the EC/pH/T meter. The measured EC values at 25 ��C were used to calculate the corrected EC25 values. By multiplying organic carbon contents with 1.724 organic matter contents of the samples were calculated [45]. Soil texture was determined by using the ��Hydrometer Method�� in [44] and described based on the USDA texture classification system.Table 1.Some physical and chemical
The prototype of biosensors was first proposed by Clark and Lyon in 1962 [1].
The analytical method of detecting organisms actually exploits the molecular recognition between enzyme and acceptor. This concept involves placement of an enzyme in close proximity to an electrode surface, where the enzyme is able to catalyze a reaction. The analysis is based on the measurements of the consumption of an elective reactant (O2) and the production of an electroactive product (H2O2) [2]. The sensing mechanism of the biosensor is dependent on the biological specificity of the enzyme-catalyzed reaction and the selectivity of the ion-selective electrode, and hence, the characteristics of the biosensor are strongly related to the selectivity of the ion-selective electrodes.
The enzyme electrode is a miniature chemical transducer which functions by combining an electrochemical procedure with immobilized enzyme activity. In 1967, Updike and Hicks used glucose oxidase immobilized on a gel to measure the concentration of glucose in biological solutions and in tissues in vitro [3]. From this moment on, many researches devoted to the development of biosensors, such as the O2, H2O2, H2, H+, NH3, CO2 electrodes and ion-sensitive field effect transistor (ISFET) [4]. An ISFET can be considered as a special type of the MOSFET without a metal or polysilicon gate, with the gate coated with a hydrogen ion-sensitive layer [5]. The gate of ISFET is directly exposed to the buffered solution to detect the concentration of hydrogen ion. The extended gate field effect transistor (EGFET) is another sensing structure which isolates the FET from the chemical environment.
Biosensors mainly composed of two parts. The first part is the sensing element which receives the input signal for the biological sensor. It can be the organism molecules, tissue or molecular recognition elements of individual cells. The Carfilzomib other part is the electronic circuit which processes the http://www.selleckchem.com/products/Lenalidomide.html quantified electronic signals from sensing element and outputs the processing result [6].