Washington, October 27 : Mayo Clinic researchers have come up with a method of controlling the viruses behind potential cancer therapeutics, so that they will not damage healthy tissues.

The researchers believe that such viruses can be restricted to specific tissues by engineering the virus''s genetic sequence with the aid of microRNAs.

They say that the microRNAs destabilize the virus''s genome, making it impossible for the virus to run amok.

"Our findings demonstrate a new tool for molecular medicine that should also help allay concern over the use of viruses as a therapeutic delivery system," Nature Medicine quoted Dr. Stephen Russell, Mayo physician-scientist and lead author of the study, as saying.

Washington - The race for the US presidency was entering the backstretch Monday as Democrat Barack Obama pushed to keep Republican John McCain on the defensive in states long regarded as Republican strongholds - like Virginia and Florida.

Senator Obama was to deliver a speech in the hotly contested manufacturing-intensive Rust Belt state of Ohio that his campaign called his "closing argument."

Islamabad - At least 20 people were killed in a missile attack carried out by a suspected US drone in Pakistan's tribal region, officials said Monday.

A single missile fired from a pilotless aircraft hit the house of local Taliban commander Mohammad Omar late Sunday in the Shakai area of South Waziristan, they said.

"Commander Omar and 19 more people died in the strike, and three were injured," a security official said.

The attack demolished Omar's house and badly damaged two adjacent buildings.

Washington - Online scammers are out in full force these days. They'll try to dupe you by e-mail or through websites. And they typically want one of two things: your money or your personal information. To make sure you don't give them either, you need to keep abreast of some of the tricks they're using. Read on to learn about a few.

Q: I received an e-mail from what appears to be my credit card company. The e-mail says that my credit card was used in a number of fraudulent transactions, and a few were listed that do appear fraudulent. There's a Word attachment that the company wants me to fill out and return. Is this a scam?

Tokyo/Obama, Japan - Welcome to Obama. Elderly residents in the small port town on Japan's west coast are getting ready for the US presidential elections, playing hula music to support their hero - Barack Obama.

The vast majority of them knows the Hawaii-born senator only from the television screen. And, like most of their countrymen, they did not give a toss about politics at the other side of the Pacific Ocean until recently.

But now, the residents of Obama, Japan, are cheering for the Democratic candidate because he puts their town, 400 kilometres west of Tokyo, on the map.

San Francisco - If anyone still questioned the power of the internet to play a key role in the general elections, the recent fundraising figures touted by Barack Obama should put all doubts to rest.

The Democratic presidential nominee raised a staggering 150 million dollars in September - most of which came from small donors who gave less than 100 dollars each through Obama's website.