Biosensors or enzyme electrodes

Biosensors or enzyme electrodes INTRODUCTION OF BIOSENSORS:- Biosensors or enzyme electrodes invariably refer to such devices that sence and analyze biological informations. A biosensor is a device that detects, records, and transmits information regarding a physiological change or the presence of various chemical or biological materials in the environment. More technically, a biosensor is a probe that integrates a biological component, such as a whole bacterium or a biological product (e.g., an enzyme or antibody) with an electronic component to yield a measurable signal. Biosensors, which come in a large variety of sizes and shapes, are used to monitor changes in environmental conditions. They can detect and measure concentrations of specific bacteria or hazardous chemicals; they can measure acidity levels (pH). In short, biosensors can use bacteria and detect them, too. PRINCIPALS OF BIOSENSORS:- A biosensor essentially comprise of the following two major parts 1- Biological component- For sensing the presence as well as concentration of analyte. In the presence of a certain molecule the biological system changes the environment. The measuring device sensitive to this change sends a signal. This signal can be converted into the measurement parameter. Often the biological system is an actual cell. The key thing to remember is that it is an actual organism that detects the concentration change of the molecule in the media. This organism could be the same one as the one in the media or it could be different. In either case it must be kept separate from the media. This can be done with a membrane that is permeable to the molecule that is being measured but impermeable to the cells and most other macromolecules in the reactor media. 2- Physical component:- Transducer:- A device that converts energy from one form into another e.g., telephone companies use transducers to convert sound energy into electrical energy to be carried long- distance through telephone lines and then another transducer a t the receiving end to convert the electrical energy back into sound A biosensor is a sensing device that consists of a biological component coupled to a transducer that converts biochemical activity into, most commonly, electrical energy. Types of Biosensors:- There are different types of biosensors, which have different applications. These are listed below. Calorimetric biosensor Potentiometric biosensor Amperometric biosensors Optical biosensor Acoustic wave biosensors Calorimetric biosensor:- When the physical change is heat, released or absorbed by the reaction it is calorimetric biosensor. It measures the change in temperature in the solution containing analyte Separate thermistors measure the temperature of the solution before entry into the small packed bed column containing immobilized enzyme and also at the time of leaving the column. Calorimetric biosensors are most widely applicable and can be used to measure turbid and strongly coloured s olutions. Maintenance of constant sample temperature is the disadvantage of this type. At the transducer surface, an electrical potential is produced due to changed distribution of electrons and this type of biosensors are called potentiometric biosensors. They use ion sensitive electrodes, commonly pH meter glass electrodes for cations, glass pH electrodes coated with a gas-selective membrane for CO2, NH3 or H2S or solid-state electrodes. These electrodes convert the biological reaction into electric signal. Potentiometric Biosensors

Body art and ornamentation of the Egyptian Copts and Hindi India Essay

Body art and ornamentation of the Egyptian Copts and Hindi India cultures - Essay Example d person as incomplete and they usually use a matchmaker to find possible marriage couples unlike the Copts who look for their own partners (Lindsey, 2012). After the couples are matched by the matchmaker the go to their parents for approval after which wedding preparations start immediately. These Hindu marriages happen in the most spiritual day- ocuta, early in the moment where the girl is led by the male around a fire (punit) seven times (Lindsey, 2012). The Hindi culture does not consider baptism in water. On the other hand, the Egyptian Copts baptize their children seven days after birth where the child is baptized by the father (Lindsey, 2012). The father washes the child in a washbowl and later prays the Salat elTist- the washbowl prayer. This process tales about 30 minutes and is followed by a two hour prayer where the child is given the holy secrets called the Tanawel (Lindsey, 2012). If a member of the Coptic culture dies, his/her body is washed by a family member, covered by a shroud and the whole family goes to church to pray for the dead. The priest then conducts the funeral service and the body is buried (Lindsey, 2012). There is no specific day for burial. On the other hand, the Indians had dissimilar ways of burying their dead based on their tribe (Lindsey, 2012). Some buried them under the ground in coffin while other burned their dead. The ashes were later buried or conserved in a sacred place depending on their social status (Lindsey, 2012). The principal garment that was worn during the ancient Coptic period was a tunic, usually made of linen but sometimes made of wool, with a tapestry-woven decoration. Over it was the pallium – an oblong cloak which was similarly decorated as the tunic (Dimand, 1930). These tunics had adornments at the front and back together with shoulder bands of dissimilar lengths, and square roundels on the shoulders. The lower edge had trims of horizontal bands that turned at right angles on each side (Dimand, 1930).

Graphic design is the branch of visual art Essay

Graphic design is the branch of visual art - Essay Example By effectiveness, we mean how much power a design has to motivate people or help them identify a company. For example, where a one or two letter sign may be effective in identifying a company such as BP, it is not effective for another company simply identified as B. Plus; presentation of an idea does not necessarily mean it was communicated accurately. A scribbled "keep off grass" sign is not as effective as a neatly designed "keep off grass" sign with an appropriately designed logo. Also, just because a sign communicates effectively does not mean what it communicates is good. Governments have become masters at influencing citizens with graphic design by communicating messages sometimes to support darkly political objectives. Graphic design is the branch of visual art dedicated to communicating messages. It is most used in marketing and brand recognition strategies. Having watch and listened to a video of a talk about design given by David Carson, I walk away with certain understandings about graphic design.