Composite nanofibers open next chapter in orthopaedic biomaterials

ScienceDaily (Aug. 7, 2012) ? Bioengineered replacements for tendons, ligaments, the meniscus of the knee, and other tissues require re-creation of the exquisite architecture of these tissues in three dimensions. These fibrous, collagen-based tissues located throughout the body have an ordered structure that gives them their robust ability to bear extreme mechanical loading.

Many labs have been designing treatments for ACL and meniscus tears of the knee, rotator cuff injuries, and Achilles tendon ruptures for patients ranging from the weekend warrior to the elite Olympian. One popular approach has involved the use of scaffolds made from nano-sized fibers, which can guide tissue to grow in an organized way. Unfortunately, the fibers' widespread application in orthopaedics has been slowed because cells do not readily colonize the scaffolds if fibers are too tightly packed.

Robert L. Mauck, PhD, professor of Orthopaedic Surgery and Bioengineering, and Brendon M. Baker, PhD, previously a graduate student in the Mauck lab at the Perelman School of Medicine, University of Pennsylvania, have developed and validated a new technology in which composite nanofibrous scaffolds provide a loose enough structure for cells to colonize without impediment, but still can instruct cells how to lay down new tissue. Their findings appear online this week in the Proceedings of the National Academy of Sciences.

"These are tiny fibers with a huge potential that can be unlocked by including a temporary, space-holding element," says Mauck. The fibers are on the order of nanometers in diameter. A nanometer is a billionth of a meter.

Using a method that has been around since the 1930s called electrospinning, the team made composites containing two distinct fiber types: a slow-degrading polymer and a water-soluble polymer that can be selectively removed to increase or decrease the spacing between fibers. The fibers are made by electrically charging solutions of dissolved polymers, causing the solution to erupt as a fine spray of fibers which fall like snow onto a rotating drum and collect as a stretchable fabric. This textile can then be shaped for medical applications and cells can be added, or it can be implanted directly -- as a patch of sorts -- into damaged tissue for neighboring cells to colonize.

Increasing the proportion of the dissolving fibers enhanced the ability of host cells to colonize the nanofiber mesh and eventually migrate to achieve a uniform distribution and form a truly three- dimensional tissue. Despite the removal of more than 50 percent of the initial fibers, the remaining scaffold was a sufficient architecture to align cells and direct the formation of a highly organized extracellular matrix by collagen-producing cells. This, in turn, led to a biologic material with tensile properties nearly matching human meniscus tissue, in lab tests of tissue mechanics.

"This approach transforms what was once an interesting biomaterials phenomenon -- cells on the surface of nanofibrous mats -- into a method by which functional, three-dimensional tissues can be formed," says Mauck.

It is a marked step forward in the engineering of load-bearing fibrous tissues, and will eventually find widespread applications in regenerative medicine, say the authors.

Mauck and his team are currently testing these novel materials in a large animal model of meniscus repair and for other orthopaedic applications.

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Story Source:

The above story is reprinted from materials provided by University of Pennsylvania School of Medicine, via EurekAlert!, a service of AAAS.

Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Brendon M. Baker, Roshan P. Shah, Amy M. Silverstein, John L. Esterhai, Jason A. Burdick, and Robert L. Mauck. Sacrificial nanofibrous composites provide instruction without impediment and enable functional tissue formation. PNAS, August 7, 2012 DOI: 10.1073/pnas.1206962109

Note: If no author is given, the source is cited instead.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

Source: http://feeds.sciencedaily.com/~r/sciencedaily/top_news/~3/TUQgIH5N7oE/120807132304.htm

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Analysis: As U.S. gets tough on oil pipelines, outages get longer

WASHINGTON (Reuters) - Enbridge Inc's ruptured pipeline, which leaked about 1,200 barrels of crude into a rural Wisconsin field 10 days ago, seemed like no big deal.

The scene was contained within hours, the line repaired within days. The leak was miles from running water or endangered wildlife. The immediate impact was limited to the evacuation of two houses and "veterinary attention" for some horses and cows.

And yet some experts and traders warn that Canada's Enbridge might not be able to restart its 318,000-barrel-per-day Line 14 for weeks - or even months - as a once-obscure U.S. regulatory agency gets more comfortable with flexing its recently enhanced muscles.

The Pipeline and Hazardous Materials Safety Administration is in the spotlight after two big accidents in 2010 - BP Plc's Macondo disaster in the Gulf of Mexico and another Enbridge leak of 20,000 barrels into Michigan's Kalamazoo River in one of the biggest spills onshore.

"Pipeline accidents have a high profile right now," said Andy Black, head of the Association of Oil Pipelines trade group.

The U.S. Transportation Department, which oversees the PHMSA, began a new pipeline safety effort in 2011, urging operators to replace aging infrastructure and winning Congressional support for more resources and enforcement powers.

Based on interviews with industry experts and a Reuters review of the agency's recent enforcement record, the change has been noticeable, and the message is clear: If pipelines are found wanting, do not count on a quick resumption in oil flows. That message may be doubly true for Enbridge, which has suffered a string of incidents -- one on the same pipeline years earlier.

Last Tuesday, the agency issued Enbridge a corrective action order, a tough but not uncommon response to a spill. Since 2007, the PHMSA has issued 23 such orders.

But the agency went a step further on Thursday. It demanded an exhaustive safety plan, which it and an independent auditor must review, for the entire 1,900-mile (3,060-km) Lakehead pipeline system, not just Line 14. Those were among the toughest terms for any order since a pair of BP oil spills in Alaska in 2006.

"This is PHMSA saying: ?We mean business,'" said industry consultant Don Deaver, a former Exxon pipeline engineer. It could take weeks to hire the independent inspector and begin a review of the system, he added.

BLACK EYE

The Wisconsin spill was the latest black eye for Enbridge's pipeline network, the main conduit for Canadian crude exports and one of the largest systems in the world. The company says it has had a 99.999 percent success rate in delivering 12 billion barrels over the past decade and is investing $800 million this year as it strives for a perfect record.

But U.S. Transport Secretary Ray LaHood blasted Enbridge last week, demanding the company demonstrate why it should be able to keep operating the pipeline without a complete replacement or major overhaul.

The rupture on Line 14 left a 4-foot by 6-inch (1.2-metre by 15-cm) gash, according to the initial report. The cause of the pipeline failure has not been determined.

Enbridge said on Friday that it had submitted safety plans for both Line 14 and the Lakehead system and was waiting for news. Neither the company nor the PHMSA offered a timetable for when shipments might resume.

The PHMSA will move forward when it is certain that the pipeline is not posing a risk to public safety, said spokeswoman Jeannie Layson.

The agency's pipeline oversight has faced some criticism in the past.

In a report on Enbridge's 2010 spill in Michigan released last month, the National Transportation Safety Board charged that PHMSA's review of Enbridge's oil spill response plan in that case was "inadequate."

Looking at the incident on its own merits, some see little reason for holding up approval.

"I'd be really surprised if this not up and running pretty darn quick, unless they find something structurally flawed," said Sarah Emerson, president of consulting firm Energy Security Analysis Inc in Boston.

Oil traders were less certain.

The disruption helped trigger a record surge in Chicago wholesale gasoline premiums as local refineries operated by BP and Exxon Mobil Corp face tighter supplies. It also threatens to depress crude prices in Canada as a lack of alternative pipelines leaves producers few avenues for export.

"I am expecting an extended standoff - weeks not days," said one crude trader.

CORRECTIVE ACTION

At issue is the corrective action order, a list of demands the PHMSA can issue whenever it determines that a pipeline is "hazardous to life, property, or the environment."

The agency determines how and when to apply an order, based on the age of the pipe, the commodities being transported, the operating pressure, the surrounding area and any other factors "deemed important" by the PHMSA associate administrator.

According to a Reuters review of such orders over the past five years, most followed large pipeline leaks or spills in sensitive areas.

The remedies tend to follow a fairly clear pattern.

The orders typically require the PHMSA's permission for a company to resume operations on the pipeline in question. They usually set out a number of additional measures: running the pipeline at reduced pressure; conducting mechanical or metallurgical tests within a month, and additional tests within several months; and reporting more frequently to regulators.

Richard Kuprewicz, head of pipeline consulting firm Accufacts Inc, said Enbridge's history was a major reason why a relatively small spill is getting such a close look.

Besides the 2010 spill, Enbridge's Line 14 experienced a leak of 1,500 barrels in Wisconsin back in 2007 -- an incident that did not result in a corrective order. In November of that year, another Enbridge line caught fire in northern Minnesota, killing two workers.

"There are other issues showing up that indicate the integrity management program is seriously incomplete," Kuprewicz said.

HARD TO PLEASE

It also seems to be getting more difficult for companies to satisfy the PHMSA, whose most powerful enforcement tool is blocking the operation of a line. The agency has rarely fined a company more than $1 million; the $3.7 million penalty it issued against Enbridge a month ago for the 2010 spill was the largest ever.

Of five corrective orders issued to oil companies between 2007 and early 2010, none resulted in the closure of a pipeline for more than a week, according to the agency's own data. The longest outage - five days - occurred on Line 2 of Enbridge's Lakehead system, which spilled 2,237 barrels of crude in Neche, North Dakota, in January 2008, the data showed.

But outages have tended to last far longer since the Michigan spill in mid-2010 heightened public anxiety over oil pipelines. Of 14 incidents that resulted in corrective action orders since that leak, at least eight have resulted in pipeline closures of 25 days or more.

For example, Exxon Mobil's Silvertip line received a corrective order after a spill in Yellowstone County, Montana, last year and was shut for 85 days. Another Exxon pipeline in Louisiana was still shut after a leak on April 28; the company has requested a hearing to discuss aspects of the order.

"The fines are still small - a drop in the bucket compared to the revenues that pipeline companies generate," said Deaver, the former Exxon engineer.

But Deaver said Secretary LaHood's hard-hitting statement demanding Enbridge demonstrate why it should be allowed to continue operating its pipeline without major changes "indicates they are getting more serious."

(Editing by Lisa Von Ahn and Marguerita Choy)

Source: http://news.yahoo.com/analysis-u-gets-tough-oil-pipelines-outages-longer-161722504--finance.html

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Police: 7 dead in shooting at Sikh temple in Wis.

OAK CREEK, Wis. (AP) ? At least six people were killed Sunday when a gunman opened fire at a Sikh temple near Milwaukee, authorities said. The suspected shooter later died in an exchange of gunfire with police.

Police were called to the Sikh Temple of Wisconsin in the suburb of Oak Creek on Sunday morning, when witnesses said several dozen people were gathering for a service.

Greenfield Police Chief Bradley Wentlandt said the first officer to arrive encountered a man police believe was the shooter. The two exchanged gunfire, and the suspect was killed, he said.

Wentlandt said police do not believe a second shooter was involved. He said tactical units went through the temple. They found four people dead inside and three outside the building, including the suspected shooter, he said.

It's unclear how many others were wounded. Wentlandt said he had been told the officer who exchanged gunfire with the suspect and another person had been taken to hospitals. He said the officer was shot multiple times and is in surgery.

The spokeswoman for the area trauma center said three victims were being treated there, including one in surgery.

Sukhwindar Nagr, of Racine, said he called his brother-in-law's phone and a priest at the temple answered and told him that his brother-in-law had been shot, along with three priests. The priest also said women and children were hiding in closets in the temple, Nagr said.

Sikh rights groups have reported a rise in bias attacks since the Sept. 11, 2001, terrorist attacks. The Washington-based Sikh Coalition has reported more than 700 incidents in the U.S. since 9/11, which advocates blame on anti-Islamic sentiment. Sikhs don't practice the same religion as Muslims, but their long beards and turbans often cause them to be mistaken for Muslims, advocates say.

Sikhism is a monotheistic faith that was founded in South Asia more than 500 years ago. It has roughly 27 million followers worldwide. Observant Sikhs do not cut their hair; male followers often cover their heads with turbans ? which are considered sacred ? and refrain from shaving their beards.

There are roughly 500,000 Sikhs in the U.S., according to estimates. The majority worldwide live in India.

___

Associated Press writers Gretchen Ehlke in Milwaukee, Pat Condon in Minneapolis and Sophia Tareen in Chicago contributed to this report.

Source: http://news.yahoo.com/police-7-dead-shooting-sikh-temple-wis-191517233.html

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Enjoy Traveling With Lower Stress By Planning Well ...

It is important to stick to a food budget while traveling. Many people spend way too much money on food because it can be exciting to try things that you?ve never had before. If you have an idea of what you want to spend on a meal before you go into the restaurant, you are more likely to stay within your means.

No matter what your intentions are, you should always join the airlines frequent travel club. Even if you never fly again, you may receive a perk just for joining. On the other hand, you may fly with them a few times and you will receive benefits every time that you do.

If you are traveling to a foreign country, you should make it a point to order some smaller denominations of the foreign currency. By sticking with small amounts, you are less likely to fall victim to unscrupulous vendors, and these amounts are perfect for use as cab fare, tips, and cold beverages.

Never put important medication, electronics, or documents into your checked baggage! If something is important or would cause serious problems if it were lost, make sure it stays with your carry-on bag, and keep a close eye on it while going through security. You?re always better off safe than sorry.

A small calculator that can be tucked into your wallet or pocket can be essential when traveling abroad. Use it to help figure currency conversions and know what that trinket will cost before blindly shelling out unfamiliar foreign currency or coins and hoping the shopkeeper is honest when handing over any change due.

The best part of traveling is being able to spend freely once you get to your destination. While the hotel and the flight are usually the most expensive part, the best trips usually involve spending a ton of money out and about. So before you travel set up a savings plan such that you have a fat wallet after paying for the hotel and the flight so you can maximize your enjoyment.

Don?t forget to look up the time zones for where you will be traveling to and staying. Many people don?t realize that there is a significant time difference that will not only play a role in your sleep schedule, but also in your communication efforts to those still at home.

When going through airport security with your pet you will be required to take them out of their carrier. The security will then scan the carrier to be sure that it is safe for travel. You need to make sure that your pet will be able to handle the hustle and bustle of the airport before attempting to travel with them.

Whether traveling to see a family member or as part of an adventurous expedition, everyone needs some planning and preparation for their trip. Hopefully you learned something from reading this article that will help you on your next vacation and maybe something you can pass along to a friend.

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Source: http://articlereference.net/travel-leisure/enjoy-traveling-with-lower-stress-by-planning-well.html

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