Biological computer
Sunday, May 31, 2009
INTRODUCTION:-
Nowadays Biological computers have emerged as 
an interdisciplinary field that draws together molecular biology, chemistry, computer science and mathematics. The highly predictable hybridization chemistry of DNA, the ability to completely control the length and content of oligonucleotides, and the wealth of enzymes available for modification of the DNA, make the use of nucleic acids an attractive candidate for all of these nanoscale applications. A 'DNA computer' has been used for the first time to find the only correct answer from over a million possible solutions to a computational problem. Leonard Adleman of the University of Southern California in the US and colleagues used different strands of DNA to represent the 20 variables in their problem, which could be the most complex task ever solved without a conventional computer. The researchers believe that the complexity of the structure of biological molecules could allow DNA computers to outperform their electronic counterparts in future. Scientists have previously used DNA computers to crack computational problems with up to nine variables, which involves selecting the correct answer from 512 possible solutions. But now Adleman's team has shown that a similar technique can solve a problem with 20 variables, which has 220 - or 1 048 576 - possible solutions. Adleman and colleagues chose an 'exponential time' problem, in which each extra variable doubles the amount of computation needed. This is known as an NP-complete problem, and is notoriously difficult to solve for a large number of variables. Other NP-complete problems include the 'travelling salesman' problem - in which a salesman has to find the shortest route between a number of cities - and the calculation of interactions between many atoms or molecules. Adleman and co-workers expressed their problem as a string of 24 'clauses', each of which specified a certain combination of 'true' and 'false' for three of the 20 variables. The team then assigned two short strands of specially encoded DNA to all 20 variables, representing 'true' and 'false' for each one. In the experiment, each of the 24 clauses is represented by a gel-filled glass cell. The strands of DNA corresponding to the variables - and their 'true' or 'false' state - in each clause were then placed in the cells. Each of the possible 1,048,576 solutions were then represented by much longer strands of specially encoded DNA, which Adleman's team added to the first cell. If a long strand had a 'subsequence' that complemented all three short strands, it bound to them. But otherwise it passed through the cell. To move on to the second clause of the formula, a fresh set of long strands was sent into the second cell, which trapped any long strand with a 'subsequence' complementary to all three of its short strands. This process was repeated until a complete set of long strands had been added to all 24 cells, corresponding to the 24 clauses. The long strands captured in the cells were collected at the end of the experiment, and these represented the solution to the problem.
WORLD'S SMALLEST COMPUTER:-
The world's smallest computer (around a trillion can fit in a drop of water) might one day go on record again as the tiniest medical kit. Made entirely of biological molecules, this computer was successfully programmed to identify - in a test tube - changes in the balance of molecules in the body that indicate the presence of certain cancers, to diagnose the type of cancer, and to react by producing a drug molecule to fight the cancer cells.
DOCTOR IN A CELL:-
In previous biological computers produced input, output and "software" are all composed of DNA, the material of genes, while DNA-manipulating enzymes are used as "hardware." The newest version's input apparatus is designed to assess concentrations of specific RNA molecules, which may be overproduced or under produced, depending on the type of cancer. Using pre-programmed medical knowledge, the computer then makes its diagnosis based on the detected RNA levels. In response to a cancer diagnosis, the output unit of the computer can initiate the controlled release of a single-stranded DNA molecule that is known to interfere with the cancer cell's activities, causing it to self-destruct.
Posted bySaini at 4:43 PM 0 comments
Labels: Technology
Dell's Studio 14z laptop for gamers and students
Thursday, May 28, 2009
Dell has introduced a new Studio laptop powered by NVIDIA's GeForce 9400M graphics processor. The GPU, which delivers up to five times faster graphics performance than Centrino 2 
notebooks, significantly accelerates image editing, video playback and video
According to Dell, the Studio 14z is ideal for quickly converting video from desktop resolution to personal media player format. The laptop is also capable of rendering high-definition Blu-ray video and supports a number of popular games, including Call of Duty: World at War, The Sims 3 and World of WarCraft.
"Our groundbreaking GeForce 9400M graphics processor gives the Dell Studio 14z superior performance at a solid value," explained Rene Haas, general manager for notebook GPUs. "It delivers a great experience whether you're working or playing, catching up with your friends on Facebook, enjoying high definition video, or playing games like World of WarCraft."
Posted bySaini at 11:34 PM 0 comments
Labels: Technology
Satyam Computer surges over 11 pc on BSE amid board meeting
Wednesday, May 27, 2009
amid the meeting of its board members on
Friday.
Shares of Satyam ended the day at Rs 53.65, up 11.54 per cent from its previous close. During the trade, the scrip had soared 17 per cent to touch its intra-day high of Rs 56.25.
Similar trend was seen on the National Stock Exchange, where the stock closed at Rs 53.55, up 11.33 per cent from its last close. During the intra-day trade, shares of Satyam had touched a high of Rs 56.40, up 17.25 per cent.
On volume front, over 15.46 crore shares changed hands on both the bourses.
Four nominee directors of Tech Mahindra (the new owner of Satyam Computer), including its Chief Executive Vineet Nayar, were today appointed on the board of Satyam Computer, with effect from June 1.
The other three nominee directors on behalf of Venturbay Consultants (an arm of Tech Mahindra), which acquired 31 per cent stake in the Hyderabad-based company in April, include C P Gurnani, Sanjay Kalra and Ulhas N Yargop, Satyam said in a filing to the Bombay Stock Exchange.
The appointment of the nominee directors comes pursuant to the completion of the share purchase agreement between Tech Mahindra and Satyam Computer Services, under which the new owner of the IT firm had completed the acquisition of a 31 per cent stake in the company for Rs 1,756 crore.
Posted bySaini at 6:19 PM 0 comments
Labels: Technology
