Washington, Mar 13 : Hollywood actress Keira Knightley has decided to quit the `Pirates of the Caribbean' franchise, which made her a household name, as she has refused to reprise her role as aristocrat-turned-swashbuckler Elizabeth Swann in the series' 4th flick.

"It was a completely fantastic experience, and it was an amazingly large portion of my life, but I don''''t think I need to go there again. I think that it''''s done," Contactmusic quoted her as saying.

Knightley, however, insisted that she was a big fan of the flick and its lead actor Johnny Depp.

She even said that she was eagerly waiting to watch the forthcoming flick.

New York, Mar 13 : Singer Kelly Clarkson, who returned to the `American Idol' stage to belt out her latest single `My Life Would Suck Without You', sparked pregnancy rumours after she was spotted looking more curvilinear than her usual self.

The original American idol winner confidently took to the stage clothed in a form-fitting black mini-dress, knee-high black boots, tights and a shimmery sequined shrug, but she raised eyebrows with her rounded body.

However, she immediately shot down the rumours, saying that she was not pregnant.

"She is not pregnant," the New York Daily News quoted a representative for Kelly as saying.

Washington, Mar 13 : Hollywood actress Reese Witherspoon is desperate to shed her fragile image by acting in action flicks.

The `Man In The Moon' actress has revealed that lending her voice to 3D animation flick Monsters Vs Aliens made her inclined towards signing more explosive projects.

Washington, Mar 13 : Taking a major step towards AIDS research, Rutgers scientists have almost created an HIV vaccine that shows promise in stopping an unusually diverse set of HIV isolates or varieties.

AIDS researchers Gail Ferstandig Arnold and Eddy Arnold and their colleagues took a piece of HIV that is involved with helping the virus enter cells, put it on the surface of a common cold virus, and then immunized animals with it.

Washington, Mar 13 : Certain gene variations in some women may protect them against cervical cancer, according to scientists at Albert Einstein College of Medicine of Yeshiva University.

The researchers say that if the presence or absence of such genetic variants is known, doctors can easily tailor treatment strategies.

Virtually all cases of cervical cancer are caused by persistent infections from several of the human papillomaviruses (HPV) - a family of viruses that also cause common skin warts and genital warts.

Washington, Mar 13 : Giving up smoking before surgery can almost half the risk of post-op complications, says a new study.

"Smokers are prone to developing a number of complications after surgery, ranging from impaired wound and bone healing to life-threatening pulmonary and cardiovascular problems" said Dr Omid Sadr Azodi from the Karolinska Institute in Stockholm, Sweden.

"This is why it is so important to find feasible, financially attractive and effective ways to help patients stop smoking before surgery," the expert added.

During the study, the researchers randomly assigned 117 patients who were due to undergo general or orthopaedic surgery to an intervention and control group.