WASHINGTON, Aug. 7 (UPI) -- The U.S. space agency says it's ready for another fly-by of Saturn's moon Enceladus by the Cassini spacecraft, which will come within 30 miles.

The Monday event is designed to allow Cassini to more carefully inspect fractures on the moon from which icy jets of liquid continuously erupt.

Just after closest approach, all of the spacecraft's cameras -- covering infrared wavelength … as well as visible light and ultraviolet -- will focus on the fissures running along the moon's south pole, the National Aeronautics and Space Administration said in a statement. That is where the jets of icy water vapor emanate and erupt hundreds of miles into space.

Cassini imaging discovered evidence for the geyser-like jets on Enceladus in 2005, finding the eruptions create a gigantic halo of ice and gas around the moon, helping supply material to Saturn's E-ring.

Two more Enceladus passes are scheduled in October, and they might bring the spacecraft even closer to the moon, NASA said.

BOSTON, Aug. 7 (UPI) -- A team of U.S., Korean, and German scientists says it has halted the spread of the human immunodeficiency virus in mice by using a novel type of RNA.

Working with mice infected with HIV, the team used a Nobel Prize-winning method called ribonucleic acid interference, or RNAi, to disable the expression of three genes in T cells. That protects the cells from HIV, while preventing the transmission of HIV to other cells in the mice, the researchers said.

For the first time, we've used RNAi to dramatically suppress HIV infection in an organism, said Professor Premlata Shankar, who led the study while at Harvard University, but who is now at Texas Tech University.

Georg Fey of the University of Erlangen in Germany developed a method of transporting the interfering RNA molecules to the surface of T cells. Lee Sang-kyung of Hanyang University in South Korea discovered a way to get the molecules directly into the T cells.

The scientists say their technique might supplement or replace the drug cocktails prescribed for HIV patients, thereby reducing the sometimes harsh side effects of treatment.

The study is reported in the online issue of the journal Cell.

LONDON, Aug. 7 (UPI) -- British and U.S. scientists say giant, gaseous planets such as Jupiter and Saturn may be filled with a liquid metal alloy of helium and hydrogen.

University College London Professor Lars Stixrude and University of California-Berkeley Professor Raymond Jeanloz said their finding suggests metallic helium is less rare than thought and is produced under the kinds of conditions present at the centers of giant, gaseous planets.

The finding also speaks to one of the mysteries of large planets, said Stixrude. He said more energy is emitted from Jupiter and Saturn than they absorb from the sun. Scientists don't understand where that energy originates, although one theory is that droplets of helium condense from the planets' atmospheres and fall to their centers as helium rain, releasing gravitational energy.

But Jeanloz and Stixrude said their research shows helium and hydrogen are probably more homogenous than was thought, meaning helium rain is unlikely.

Now, we have to look elsewhere for this energy source, Stixrude said.

The study appears in the online edition of the Proceedings of the National Academy of Sciences.

KIEL, Germany, Aug. 7 (UPI) -- German scientists say they've created a technique that might avoid the necessity of transplant patients taking anti-rejection drugs the rest of their lives.

The researchers -- led by Professor Fred Fandrich at the University of Schleswig-Holstein in Kiel, Germany -- said their technique involves taking infection-fighting white cells from a transplant patient's blood and subjecting them to a highly complex procedure involving cells taken from the living or deceased donor. The tailor-made cells are then administered back to the patient.

Until now the only option for transplant patients has been to take a cocktail of drugs for the rest of their lives said Dr. James Hutchinson, the study's lead author. "These drugs can cause severe side effects and cannot always prevent the slow destructive process of chronic rejection which often leads to the failure of the transplanted organ.

That is why our use of transplant acceptance-inducing cells in kidney transplant patients is such an exciting development, as it could eventually offer patients who have had transplant surgery a much higher quality of life, free from complex drug regimes.

The procedure is reported in the August issue of the journal Transplant International.