Category Science

What is Dialysis?

Dialysis is a process of separating dissolved substances from a solution using a semi-permeable membrane which allows only some dissolved substances to pass through. Many substances such as cell walls and cellophane act as semi-permeable membranes.

Dialysis is used to remove waste-products from the blood of patients with impaired kidney function. Accumulation of waste products especially urea, in the blood can prove fatal.

Dialysis of blood is carried out using a dialysis machine. Blood drawn from the artery in the forearm of the patient is passed through a semi-permeable membrane. The tubing is placed in a solution called dialysis fluid. Since the blood has a high concentration of impurities compared to the dialysis fluid, a concentration gradient builds up. This results in a flow of soluble impurities from the blood into the dialysis fluid. This continues till the concentrations on each side of the membrane are balanced. To prevent clotting of blood in the dialysis machine, the anti-clotting substance heparin is used.

 

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What is E-mail?

E-mail is the short form for electronic mail, which is based on the use of computers for the transmission of messages rather than through the postal system. The e-mail system connects a network of personal computers (PC) spread over hundreds of locations within a country or across the globe. A PC is set-up as a message server in the system. The users at other PCs can link up with the server at any time to receive and transmit messages.

Each user of the e-mail system is allotted a code number or address in the e-mail directory. To send a message, a user has to “key-in” the message in his PC along-with the directory numbers allotted to him and the receiver of the message. The sender can indicate if the message is confidential or universal and also set a time limit for its retention. The receiver, on receiving the message at his computer terminal, can get it printed on paper.

 The main advantages of e-mail are that it cuts down the delay involved in postal transmission of messages. Moreover, messages can be sent at any time of day or night which are stored and can be retrieved by the recipient at his or her convenience. Besides once the contact between the transmitter and receiver PCs is established e-mail requires only a few minutes time to transmit even a bulky message. 

What is El Nino?

The El Nino is a narrow current of warm water that appears off the coast of Peru sometime in December-January and which lasts till March. The name literally means ‘The Child’ and refers to the Child Christ, apt because the appearance of the current coincides with Christmas. As it flows southward along the west coast of South America, it warms the cold waters of the coast of Ecuador and Peru.

El Nino was first recorded as early as in 1726 and it has returned on an average of once every four years. El Nino is believed to be related to a shift in air movements over the tropical Pacific Ocean. Changes in wind direction bring about changes in the circulation and temperature of the oceans. This in turn further disrupts ocean currents and air movements.

A powerful El Nino in 1982 and 1983 caused severe drought in Australia and Indonesia. It also caused storms in California and rains and floods in Ecuador and Peru. The El Nino effect also profoundly affects the Indian monsoons.

 

What is Endoscopy?

Endoscopy is a harmless and painless method of diagnosing diseases of any of the hollow organs of the body (like throat, stomach or intestine) by looking directly into the affected organ using a probe called endoscope. It is a hollow metallic tube fitted with a light source and a viewing system.

Modern endoscopes make use of flexible bundles of optical fibres both for transmitting light to the organ and transmitting the image to the eyepiece outside for viewing.

Since the endoscope gives a direct view of the affected body parts, patients need not go for complicated investigations.

Advanced endoscopes may have surgical attachments to carry out minor operations or biopsy.

 

 

What is FAX?

Fax or facsimile is a device used for transmission of a written document, photograph, map or any other graphic material electronically. It is one of the variants of e-mail. For transmission the original document is placed in the facsimile or fax machine which scans the document and converts the written or graphic information into electronic signals and establishes a link-up with a similar receiving fax machine at the receiving end. The receiving fax reconverts the electronic signals into written or graphic form. As the sending machine scans the documents, the receiving machine reproduces the scanned image which is an exact duplicate of the originals. A typical fax machine can transmit a document of A-4 size in less than a minute over thousands of kilometres. Since fax operates through the normal telephone lines, the fax number is usually a telephone number. Also the same STD and ISD codes are used for sending a fax to another city or another country. The document is scanned page-by-page in the fax machine. Like the e-mail, fax communication eliminates the postal delay and is very convenient for communication between persons located in different time zones, but it costs more than the e-mail. 

Why is C. V. Raman considered to be a scientist par excellence?

Sir C. V. Raman is best known for his work in the field of light scattering. Raman was intrigued by the blue colour of glaciers and the Mediterranean Sea and wanted to unravel the mystery as to why water, a colourless liquid, appeared blue to the eyes.

    Thus, he began a series of experiments on the scattering of light which ultimately led to what came to be known as the ‘Raman Effect’. Raman also discovered that when light interacts with a molecule, the light can donate a small amount of energy to te molecule. As a result of this, the light changes its colour and the molecule vibrates.

   The change of colour can act as a ‘fingerprint’ for the molecule. Today, Raman spectroscopy, which relies on these ‘fingerprints,’ is used in laboratories all over the world to identify molecules and to detect disease such as cancer.

     Sir C. V. Raman received the Nobel Prize for Physics in 1930. He was the first Indian to win the Nobel Prize for Physics, and is considered to be a scientist par excellence.