Last week Icahn and Southeastern Asset Management Inc offered $21 billion in cash for Dell, challenging founder Michael Dell's $24.4 billion bid to take the company private.

Michael Dell and private equity firm Silver Lake want to take the company private for $13.65 per share, but stockholders, including Southeastern and T. Rowe Price, have complained that the offer severely undervalues the company.

Instead, Icahn and Southeastern, two of Dell's biggest investors, proposed to give stockholders $12 of cash for every share they own, as well as allow them to keep their stock.

Dell shares were down 0.2 percent at $13.42 in morning Nasdaq trading after the news.

In a letter to Icahn, the committee said it was not clear if he intended to make "an actual acquisition proposal that the Board could evaluate" or if he intended his offer as an alternative in the event the pending sale to Silver Lake and Michael Dell is not approved.

The committee also asked for information on the terms of the debt financing required for Icahn's proposal and "contingencies available if cash on hand or stockholder rollovers are less than anticipated," as well as financing commitment letters.

It said the proposal did not appear to take into account additional borrowing that would be required if Icahn uses the company's cash in the transaction and reduces future cash flow by selling accounts receivable.

In addition, it asked for an analysis of whether the receipt of additional shares would be taxable.

Besides asking who would make up the company's senior management team under Icahn, the committee also wanted to know his "strategy and operating plan."

It also wanted to know more about the relationship between Icahn and Southeastern.

Icahn was not immediately available for comment.

Both Icahn and Southeastern said they would finance the proposal from existing cash and about $5.2 billion in new debt.

Icahn and Southeastern together hold about 13 percent of Dell stock. The billionaire investor previously proposed paying $15 per share for 58 percent of Dell.

(Reporting by Sinead Carew; Additional reporting by Nicola Leske; Editing by Lisa Von Ahn)

CAPE CANAVERAL, Florida (Reuters) - A pair of spacewalking astronauts wrapped up a hastily planned repair job on Saturday to replace a suspect coolant pump needed to keep the International Space Station at full power.

NASA astronauts Chris Cassidy and Tom Marshburn put on spacesuits and left the space station's airlock shortly before 9 a.m. EDT to attempt to stem an ammonia coolant leak that cropped up on Thursday.

Over the next four hours, they installed a spare pump, then positioned themselves to check for signs of escaping ammonia ice crystals when the system was turned back on.

"No flakes," Cassidy reported to flight controllers at the Johnson Space Center in Houston.

Engineers will monitor the system over the next several days and beyond to make sure the pump replacement fixed the problem.

"We certainly have come a long way in identifying a potential source," said NASA mission commentator Rob Navias as the astronauts returned to the station's airlock. The entire spacewalk lasted 5-1/2 hours.

The station crew discovered a steady stream of ammonia flakes flowing away from the far left side of the station's exterior frame on Thursday. Flight controllers spent the next 48 hours diagnosing the problem and coming up with potential solutions.

Engineers believed the leak most likely was coming from in or around a 260-pound (118-kg) pump that pushes ammonia throughout the system. The coolant dissipates heat from electronics in space station's solar-powered electrical system.

The station can be reconfigured to compensate for a system shutdown, but if a second problem should occur, that likely would mean a cutback in power available for the experiments.

The $100 billion station, which flies about 250 miles above Earth, is a research laboratory for biomedical, physics, astronomical and other experiments, as well as for technology development and demonstrations.

On Sunday, station commander Chris Hadfield, the first Canadian to lead the international outpost, turns over the helm to Russian cosmonaut Pavel Vinogradov. Hadfield, Marshburn and cosmonaut Roman Romanenko, who have been aboard the station since December, are scheduled to depart on Monday.

Their replacements - NASA's Karen Nyberg, Italy's Luca Parmitano and Russian Fyodor Yurchikhin - are due to launch on May 28.

(Editing by Mohammad Zargham)

The new test, which goes on sale Wednesday, joins another one that recently came on the market. Both analyze multiple genes in a biopsy sample and give a score for aggressiveness, similar to tests used now for certain breast and colon cancers.

Doctors say tests like these have the potential to curb a major problem in cancer care overtreatment. Prostate tumors usually grow so slowly they will never threaten a man's life, but some prove fatal and there is no reliable way now to tell which ones will. Treatment with surgery, radiation or hormone blockers isn't needed in most cases and can cause impotence or incontinence, yet most men are afraid to skip it.

"We're not giving patients enough information to make their decision," said Dr. Peter Carroll, chairman of urology at the University of California, San Francisco. "You can shop for a toaster" better than for prostate treatment, he said.

A study he led of the newest test the Oncotype DX Genomic Prostate Score is set for discussion Wednesday at an American Urological Association meeting in San Diego.

The results suggest the test could triple the number of men thought to be at such low risk for aggressive disease that monitoring is a clearly safe option. Conversely, the test also suggested some tumors were more aggressive than doctors had believed.

Independent experts say such a test is desperately needed but that it's unclear how much information this one adds or whether it will be enough to persuade men with low-risk tumors to forgo treatment, and treat it only if it gets worse. Only 10 percent who are candidates for monitoring choose it now.

"The question is, what's the magnitude of difference that would change the patient's mind?" said Dr. Bruce Roth, a cancer specialist at Washington University in St. Louis.

One man may view a 15 percent chance that his tumor is aggressive as low risk "but someone else might say, 'Oh my God, let's set the surgery up tomorrow,'" he said. "I don't think it's a slam dunk."

Also unknown: Will insurers pay for the expensive test without evidence it leads to better care or saves lives?

The newest test was developed by Genomic Health Inc., which has sold a similar one for breast cancer since 2004. Doctors at first were leery of it until studies in more groups of women proved its value, and the same may happen with the prostate test, said Dr. Len Lichtenfeld, the American Cancer Society's deputy chief medical officer.

The company will charge $3,820 for the prostate test and says it can save money by avoiding costlier, unnecessary treatment. Another test for assessing prostate cancer risk that came out last summer Prolaris by Myriad Genetics Inc. sells for $3,400.

Both companies can sell the tests without Food and Drug Administration approval under separate rules that govern lab diagnostics. Myriad Genetics has published nine studies on Prolaris involving more than 3,000 patients. Genomic Health has not published any results on the prostate test, another thing that makes doctors wary. Yet it has a track record from its breast cancer test.

About 240,000 men in the U.S. are diagnosed with prostate cancer each year, and about half are classified as low risk using current methods. Doctors now base risk estimates on factors such as a man's age and how aggressive cells look from biopsies that give 12 to 14 tissue samples. But tumors often are spread out and vary from one spot to the other.

"Unless you can be sure your biopsy has hit the most aggressive part that's in the prostate, you can't be sure" how accurate your risk estimate is, explained Dr. Eric Klein, chief of urology at the Cleveland Clinic,who led early development of the Oncotype prostate cancer test.

For one study, researchers used prostates removed from 440 men. They measured the activity of hundreds of genes thought to be involved in whether the cancer spread beyond the prostate or proved fatal. A second study of biopsies from 167 patients narrowed it down to 81 genes, and researchers picked 17 that seemed to predict aggressiveness no matter the location in the tumor.

A third study used single needle-biopsy samples from 395 UCSF patients scheduled to have their prostates removed. The gene test accurately predicted the aggressiveness of their cancer once doctors were able to see the whole prostate after surgery.

Using one current method, 37 of the 395 men would have been called very low risk and good candidates for monitoring. Adding the gene test put 100 men into that category, said another study leader, Dr. Matthew Cooperberg of UCSF.The gene test shifted about half of the men into either a lower or a higher risk category.

"It went both ways that was the remarkable thing. In any category of risk it added independent information compared to the standard criteria we use today," Carroll said. "More work needs to be done, but, in my opinion, this is a very good start."

However, Dr. Kevin McVary, chairman of urology at Southern Illinois University School of Medicine and a spokesman for the Urological Association, said the test must be validated in more men before it can be widely used.

"It's not there yet," he said.

UCSF just got a federal grant to see how men choose treatments and whether this test might sway them.

"We throw all these numbers at them. Are they really going to make a better decision?" Cooperberg said.

Dean Smith, 60, a retired marketing executive from Mill Valley, Calif., is following his doctor's advice to monitor the cancer he was diagnosed with in March. He said a gene test may have made him more comfortable with that decision.

At least six of his friends suffered side effects ranging from urinary leakage to inability to have sex after having their prostates removed.

"I would suspect that having cancer and having to live with it would be very difficult for them," but it doesn't bother him, Smith said. "I will die from something other than prostate cancer, I guarantee you."

___

Marilynn Marchione can be followed at http://twitter.com/MMarchioneAP

NEW YORK (Reuters) - Baby boomers, the generation that vowed to stay forever young, are getting older, designing senior-friendly gyms and becoming their own personal trainers.

In exercise havens for the over-50 set, the cardio machines are typically low impact, the resistance training is mainly air-powered and some group fitness classes are taken sitting down.

At Welcyon gyms, founded by husband-and-wife boomers Suzy and Tom Boerboom, the average age of members is 62.

"The environment is really designed for those 50 and over," said Suzy Boerboom.

The couple created Welcyon, which has locations in Minnesota and South Dakota, in 2009. It has no tread-mills and no free weights and workouts are customized to members' levels of fitness. A smart card sets resistance, counts repetitions and adjusts workouts.

An important attraction for many boomers: background music is a combination of '40s, '50s and '60s tunes played at a much lower volume than in traditional gyms.

"It was something I could manage," said 66-year-old Bill Zortman, one of an estimated 78 million baby boomers, defined as the group born between 1946 and 1964, who make up about 26 percent of the U.S. population, according to U.S. Census reports.

His thrice-weekly workouts at a Welcyon in Sioux Falls, South Dakota, consists of riding a bicycle or using air-powered resistance machines to strengthen his legs, arms and back.

"They make sure I'm not overdoing it," Zortman said of the staff, who Boerboom said are often boomers themselves.

The absence of clanging free weights also cuts down on the racket, Boerboom said, noting that many people over 50 prefer a quieter gym.

Group fitness classes for boomers are also modified.

"We're just beginning to develop a group fitness interval training program," Boerboom said. "It will be four to six people and low impact."

The American Council on Exercise says many of their fitness professionals are baby boomers who specialize in working with older adults.

"People in their early 60's are becoming personal trainers and group fitness instructors," said Todd Galati, ACE's director of credentialing.

But they are far from the majority, as the average age of ACE's 50,000 certified fitness professionals is 42, and more than 37 percent are 40.

"Every year I talk to newly certified personal trainers, retired from their career in another field, who want to help people their age become more fit," Galati said.

A recent study published in JAMA Internal Medicine showed that a sample of baby boomers had higher rates of hypertension, diabetes, obesity and high cholesterol than their parents' generation.

"There is a big bad myth about the boomer generation being more fit," said Dr. Sheldon S. Zinberg, founder of Nifty after Fifty fitness centers for older adults. "In fact, the boomer generation is less fit than their parents were at same age."

The chain has locations in Arizona, California, Nevada, Texas, Virginia and New York. Its programs target muscle power, muscle strength, reaction time, balance and cognitive skills, he said.

"At age 40 people lose 0.8 to 1 percent muscle mass each year. By age 60 this accelerates to 1.5 percent," Zinberg said.

At Nifty after Fifty, group fitness classes range from yoga and Zumba to seated volleyball and cane fu, a self-defense class in which participants use a cane.

As with Welcyon, there are no tread-mills. "We used to use tread-mills, but we had people falling off," Zinberg said. "We use recumbent stair steppers, among other exercisers."

He advises people to get fit in their 40s and 50s, "and when you do become older, enjoy a supervised, customized program."

Boerboom said Welcyon plans to open more gyms later this year. "There are over 70 million of us boomers," she said, "and we have to take care of ourselves."

(Editing by Patricia Reaney and Dan Grebler)

Kenya's Ocean Sole sandal recycling company is cleaning the East African country's beaches of used, washed-up flip-flops.

Workers in Nairobi make about 100 different products from the discarded flip-flops. In 2008 the company shipped an 18-foot giraffe to Rome for display during a fashion week.

Company founder Julie Church says the goal of her company is to create products that people want to buy, then make them interested in the back-story.

Workers wash the flip-flops, many of which have been repaired several times. Artisans then glue together the various colors, carve the products, sand and rewash them.

Both of them are senior to me in rank and age, and they pooh-pooh the notion that anything but water vapor is being exhaled. Am I making something out of nothing, or should I be worried about this? -- CLEAN AIR

DEAR CLEAN AIR: You don't have anything to worry about, but your co-workers may. In 2009, the FDA announced the findings from a laboratory analysis that indicated that electronic cigarettes expose users to harmful chemical ingredients, including carcinogens. However, those elements were not detected in exhaled vapor.

DEAR ABBY: The woman who collaborated with me on this letter is in her 80s and lives at an assisted-living facility. I am a caregiver and a senior myself, and I have worked in this area for six years.

We read your column on the days I care for her. She loves it and responds verbally to all the letters. Many times the situations spark good conversation, even though her short-term memory is failing. Sometimes we end up howling with laughter. She's a delight and has the courage to still seek out relationships.

This is what she asked me to help her to communicate. -- KATE IN AUSTIN, TEXAS

DEAR ABBY: I have been in assisted living for seven years. There are times when it can be lonely and boring. I'd like to meet some men for companionship, conversation and perhaps romance. The men here act so much older than me. They don't start conversations. They stay in their rooms and watch TV and don't seem interested in conversations.

It's hard because my memory isn't what it used to be, but I do remember how nice it was to have male companionship. Do you have any ideas to make my life a little more interesting? -- LONELY WOMAN

DEAR LONELY: Start by making sure you participate in all the activities your assisted-living facility offers. Shared mealtimes and holiday celebrations also present opportunities to mingle.

The trick is to find something you have in common with these men -- sports, games, music, movies. Because long-term memory outlasts short-term memory, some of them might find it easier to discuss their youth than the present.

Encourage your caregiver, Kate, to take you places where you can meet other seniors. And while you're at it, why not invite some of the men to join you both during your Dear Abby sessions? It's a way to draw people out and get to know them better.

DEAR ABBY: After a six-month separation, my husband and I are reuniting. We were married for 22 years. I know for a fact he has dated and slept with several women. He's adamant that he used protection each time, but the idea of STDs has me preoccupied and worried. I have asked him to use protection with me until I get over my fear.

How long do most of today's STDs incubate, and what is a safe time to wait to remove the "rain gear"? -- LONGING FOR CONTACT

DEAR LONGING: Congratulations on your reunion. Rather than worry about this, ask your husband to schedule a doctor's appointment and be tested for any STD he might have contracted. Not all STDs have the same incubation period, but a blood test could resolve the issue and put your mind at ease.

Dear Abby is written by Abigail Van Buren, also known as Jeanne Phillips, and was founded by her mother, Pauline Phillips. Write Dear Abby ator P.O. Box 69440, Los Angeles, CA 90069.

For everything you need to know about wedding planning, order "How to Have a Lovely Wedding." Send your name and mailing address, plus check or money order for $7 (U.S. funds) to: Dear Abby, Wedding Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Shipping and handling are included in the price.)

SANTA CLARA, California (Reuters) - Intel Corp on Monday unveiled the most extensive overhaul of its Atom mobile processors, with improved performance that the PC chipmaker expects will help it challenge Qualcomm in smartphones and tablets.

The new microarchitecture, code-named Silvermont, will be a key building block in upcoming Intel chips for mobile gadgets, microservers and car entertainment systems, Chief Product Officer Dadi Perlmutter told reporters at an event on Monday.

"We have not only reduced the power in a significant manner but it comes with significant performance," Perlmutter said.

Intel's chips dominate the PC industry but the company has struggled to adapt its processors for smartphones and tablets, a market dominated by Qualcomm.

The Silvermont microarchitecture is analogous to redesigning an automobile engine that will be used a range of car models with different features, Perlmutter said.

He said it offers up to three times more computing performance than current chips and as much as five times lower power consumption.

Qualcomm and other mobile chipmakers design their processors using power-efficient technology licensed from Intel-rival ARM Holdings.

Intel introduced its Atom mobile processors for netbooks in 2008 and they have so far failed to be widely adopted in smartphones and tablets despite improvements made to them.

Silvermont will be the basis for Intel's 22-nanometer Bay Trail tablet chips due out later this year and Intel says it will more than double the performance of its current tablet chips.

It will also be used in Intel's upcoming Merrifield smartphone chips and Avoton chips for microservers.

While Silvermont improves the performance of Intel's processors, the Santa Clara, California company faces other major challenges in mobile.

It has fallen behind in launching chips with Long Term Evolution, or LTE, a high-speed wireless technology already offered by Qualcomm and increasingly found in smartphones launched in the United States, including Apple's iPhone and Samsung's Galaxy line.

(Reporting By Noel Randewich; Editing by Nick Zieminski)

LONDON (Reuters) - Is nanomedicine the next big thing? A growing number of top drug companies seem to think so.

The ability to encapsulate potent drugs in tiny particles measuring billionths of a meter in diameter is opening up new options for super-accurate drug delivery, increasing precision hits at the site of disease with, hopefully, fewer side effects.

Three deals struck this year by privately held Bind Therapeutics, together worth nearly $1 billion if experiments are successful, highlight a new interest in using such tiny carriers to deliver drug payloads to specific locations in the body.

U.S.-based Bind is one of several biotechnology firms that are luring large pharmaceutical makers with a range of smart drug nanotechnologies, notably against cancer.

And nanomedicine is also being put to work in diagnosis, with tiny particles used to improve imaging in scanners, as well as rapidly detecting some serious infections.

In future, researchers hope to combine both treatment and diagnostics in a new approach dubbed "theranostics" that would allow doctors to monitor patients via their medicines.

After much hype but limited clinical success, scientists in the nanotechnology field finally see a turning point.

"We have been hearing about the promise of nanomedicine for a long time, but it is now really starting to move," said Dan Peer, who runs a nanomedicine laboratory at Tel Aviv University.

"There is a new level of confidence in this approach among the big pharmaceutical companies ... We will see more and more products in clinical testing over the next few years and I think that is very exciting."

Nanoparticles made of polymers, gold and even graphene - a newly-discovered form of carbon - are now in various stages of development. In cancer alone, 117 drugs are being assessed using nanoparticle formulations, though most have yet to be tried on patients, according to Thomson Reuters Pharma data.

Other potential applications include treatments for inflammatory disorders, heart and brain diseases, and pain.

COLLATERAL DAMAGE

Companies are increasingly focused on better drug targeting to increase efficacy and lessen the collateral damage caused by medicinal "carpet bombing" - a particular problem in cancer, where toxic compounds are needed to kill tumors.

The work on drug-carrying nanoparticles parallels advances in using so-called "armed antibodies" to deliver drugs direct to cancer cells - an approach championed by Roche.

The Swiss group won U.S. approval in February for Kadcyla, its first such antibody-drug conjugate, which treats breast cancer with fewer side effects like hair loss.

"All these developments have prompted companies to look at new avenues because the older ways of using drugs haven't worked so well," said Robert Langer, a pioneer of nanomedicine who runs the world's largest biomedical engineering laboratory at the Massachusetts Institute of Technology.

Having worked on drug delivery since the 1970s, Langer has seen plenty of ups and downs.

The world's first nanomedicine was actually approved back in 1995 when U.S. regulators gave a green light to Doxil for treating Kaposi's sarcoma, a cancer often associated with AIDS.

Doxil - a hollow fatty ball known as a liposome with a cancer-killing drug inside it - was a breakthrough. Yet few other nanomedicines have followed.

Recent scientific advances have changed the game, however. Bind's nanoparticles, for example, are programmed to reach the right spot using targeting molecules that recognize specific proteins linked to disease on the surface of cells.

They also have a stealth covering that shields them from the immune system, in order to minimize adverse reactions.

Since January, Amgen, Pfizer and AstraZeneca have all signed up to use Bind's technology, which comes from work originally carried out in Langer's lab.

And Bind is not the only game in town. Another approach, using tiny particles of gold as drug carriers, is being explored in a deal that AstraZeneca signed in December with CytImmune.

"Anything you can do to improve targeting of tumors rather than normal tissue - whether that is through an armed antibody or nanoparticle approach - increases the chance of success," said Susan Galbraith, who leads AstraZeneca's oncology research.

PARALLEL APPROACHES

The work remains early stage and Peer of Tel Aviv University says all the novel carriers will have to be studied closely for potential toxicity. However, experience with liposomes is good and versions of gold nanoparticles have also been used safely for many years to treat rheumatoid arthritis.

Injecting patients with gold may sound like a pricey option but with thousands of nanoparticles fitting into the width of a human hair, the amount of metal used is tiny. Gold, unlike some other metals, is not toxic and has been used in various medical treatments for many years without harmful effects.

Bind CEO Scott Minick also thinks his polymer technology will have cost advantages over expensive antibody drugs.

Further out, Kostas Kostarelos, professor of nanomedicine at University College London, has high hopes for graphene - a one-atom-thick form of carbon. His team is currently working with graphene nanomaterials in pre-clinical experiments.

"We will see parallel development of different materials, each offering something different therapeutically," he said.

Other venture-backed nanomedicine firms include Cerulean Pharma, whose technology has made a highly potent cancer drug tolerable but which recently had disappointing results in a clinical study, and two companies looking at new vaccines.

Selecta Biosciences has a deal on food allergy vaccines with Sanofi, while Liquidia Technologies is allied with GlaxoSmithKline on vaccines and inhaled products.

MIT's Langer is convinced more Big Pharma companies will think small in future.

"You can be sure others will jump on the bandwagon sooner or later. That doesn't mean they might not jump off for a little bit too - but they will jump back on. These technologies are here to stay," he said.

(Editing by Peter Graff)

Singh, who won a middleweight bronze at the 2008 Beijing Olympics, was ordered by the ministry to take a test after local police accused him of using heroin on several occasions amid allegations from a fellow boxer.

"Vijender Singh...along with four others was subjected to an out-of-competition test for banned substances," the sports ministry said in a statement.

"The Ministry...is glad to announce that on the basis of these tests none of the boxers were found to have used any banned substances in the recent past."

Singh came under scrutiny when a fellow boxer told investigators after a $24-million drug haul in the northern state of Punjab last month that he and Singh had consumed heroin supplied by a drug dealer.

The 27-year-old Singh denied the allegation. (Reporting by Sudipto Ganguly; editing by Clare Fallon)

Cedric Makiadi gave Freiburg the lead against the run of play after half an hour when he forced the ball over the line after Jonathan Schmid's shot was parried by Augsburg goalkeeper Alexander Manninger.

Max Kruse set up the second for the team from the Black Forest region as he split the Augsburg defence with a clever through ball for Schimd and the Frenchman gave Manninger no chance with his finish.

Freiburg stayed an impressive sixth with 48 points from 32 games, which would earn them a place in the Europa League next season. The still have a mathematical chance of qualifying for the Champions League playoff round as they are four points behind fourth-placed Schalke 04 with two games to play.

Augsburg, who had won five of their previous eight games, are 16th, the relegation playoff place. They have 30 points, behind Fortuna Duesseldorf on goal difference.

Hamburg SV, seventh with 45 points, were held 1-1 at home by VfL Wolfsburg in the day's other game, a midtable clash.

Heiko Westermann headed Hamburg in front on the stroke of halftime but the inconsistent hosts were pegged back by Makoto Hasebe's header midway through the second half. (Writing by Brian Homewood in Berne, editing by Pritha Sarkar)