A single cell endoscope

ScienceDaily (Dec. 20, 2011) ? An endoscope that can provide high-resolution optical images of the interior of a single living cell, or precisely deliver genes, proteins, therapeutic drugs or other cargo without injuring or damaging the cell, has been developed by researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab). This highly versatile and mechanically robust nanowire-based optical probe can also be applied to biosensing and single-cell electrophysiology.

A team of researchers from Berkeley Lab and the University of California (UC) Berkeley attached a tin oxide nanowire waveguide to the tapered end of an optical fibre to create a novel endoscope system. Light travelling along the optical fibre can be effectively coupled into the nanowire where it is re-emitted into free space when it reaches the tip. The nanowire tip is extremely flexible due to its small size and high aspect ratio, yet can endure repeated bending and buckling so that it can be used multiple times.

"By combining the advantages of nanowire waveguides and fibre-optic fluorescence imaging, we can manipulate light at the nanoscale inside living cells for studying biological processes within single living cells with high spatial and temporal resolution," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this research. "We've shown that our nanowire-based endoscope can also detect optical signals from subcellular regions and, through light-activated mechanisms, can deliver payloads into cells with spatial and temporal specificity."

Yang, who also holds appointments with the University of California Berkeley's Chemistry Department and Department of Materials Science and Engineering, is the corresponding author of a paper in the journal Nature Nanotechnology describing this work titled "Nanowire-based single-cell endoscopy." Co-authoring the paper were Ruoxue Yan, Ji-Ho Park, Yeonho Choi, Chul-Joon Heo, Seung-Man Yang and Luke Lee.

Despite significant advancements in electron and scanning probe microscopy, visible light microscopy remains the workhorse for the study of biological cells. Because cells are optically transparent, they can be noninvasively imaged with visible light in three-dimensions. Also, visible light allows the fluorescent tagging and detection of cellular constituents, such as proteins, nucleic acids and lipids. The one drawback to visible light imaging in biology has been the diffraction barrier, which prevents visible light from resolving structures smaller than half the wavelength of the incident light. Recent breakthroughs in nanophotonics have made it possible to overcome this barrier and bring subcellular components into view with optical imaging systems. However, such systems are complex, expensive and, oddly enough, bulky in size.

"Previously, we had shown that subwavelength dielectric nanowire waveguides can efficiently shuttle ultraviolet and visible light in air and fluidic media," Yang says. "By incorporating one of our nanophotonic components into a simple, low-cost, bench-top fibre-optical set-up, we were able to miniaturize our endoscopic system."

To test their nanowire endoscope as a local light source for subcellular imaging, Yang and his co-authors optically coupled it to an excitation laser then waveguided blue light across the membrane and into the interiors of individual HeLa cells, the most commonly used immortalized human cell line for scientific research.

"The optical output from the endoscope emission was closely confined to the nanowire tip and thereby offered highly directional and localized illumination," Yang says. "The insertion of our tin oxide nanowire into the cell cytoplasm did not induce cell death, apoptosis, significant cellular stress, or membrane rupture. Moreover, illuminating the intracellular environment of HeLa cells with blue light using the nanoprobe did not harm the cells because the illumination volume was so small, down to the picolitre-scale."

Having demonstrated the biocompatibility of their nanowire endoscope, Yang and his co-authors next tested its capabilities for delivering payloads to specific sites inside a cell. While carbon and boron nitride nanotube-based single-cell delivery systems have been reported, these systems suffer from delivery times that range from 20-to-30 minutes, plus a lack of temporal control over the delivery process. To overcome these limitations, Yang and his co-authors attached quantum dots to the tin oxide nanowire tip of their endoscope using photo-activated linkers that can be cleaved by low-power ultraviolet radiation. Within one minute, their functionalized nanowire endoscope was able to release its quantum dot cargo into the targeted intracellular sites.

"Confocal microscopy scanning of the cell confirmed that the quantum dots were successfully delivered past the fluorescently labeled membrane and into the cytoplasm," Yang says. "Photoactivation to release the dots had no significant effect on cell viability."

The highly directional blue laser light was used to excite one of two quantum dot clusters that were located only two micrometers apart. With the tight illumination area and small separation between the light source and the dots, low background fluorescence and high imaging contrast were ensured.

"In the future, in addition to optical imaging and cargo delivery, we could also use this nanowire endoscope to electrically or optically stimulate a living cell," Yang says.

The nanowires used in these experiments were originally developed to study size-dependent novel electronic and optical properties for energy applications.

This research was supported by the DOE Office of Science and a grant from the National Institutes of Health.

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The above story is reprinted from materials provided by DOE/Lawrence Berkeley National Laboratory.

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. Ruoxue Yan, Ji-Ho Park, Yeonho Choi, Chul-Joon Heo, Seung-Man Yang, Luke P. Lee, Peidong Yang. Nanowire-based single-cell endoscopy. Nature Nanotechnology, 2011; DOI: 10.1038/nnano.2011.226

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/~3/rFxy1ICZASI/111220154052.htm

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Selena Gomez Cancels Concerts Due To Family Emergency

www.eonline.com:

Selena Gomez has pulled the plug on two holiday-themed concerts scheduled for tonight and tomorrow.
Her rep says Selena is OK, instead citing a "family emergency" as the reason for the abrupt cancellation.

What happened?

Read the whole story: www.eonline.com

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Source: http://www.huffingtonpost.com/2011/12/17/selena-gomez-cancels-family-emergency_n_1155723.html

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Historic visit to Libya by Pentagon chief Panetta

U.S. Secretary of Defense Leon Panetta, center right, with U.S. Ambassador to Libya Gene Crets, center left, and Gen. Carter Ham, Commander U.S. Africa Command, third from left, places a wreath at the grave site of 13 U.S. Navy sailors during a ceremony at the Protestant Cemetery in Tripoli, Libya, Saturday, Dec., 17, 2011. Panetta visited the grave site of the sailors, who where killed on the USS Intrepid in 1804. (AP Photo/Pablo Martinez Monsivais, Pool)

U.S. Secretary of Defense Leon Panetta, center right, with U.S. Ambassador to Libya Gene Crets, center left, and Gen. Carter Ham, Commander U.S. Africa Command, third from left, places a wreath at the grave site of 13 U.S. Navy sailors during a ceremony at the Protestant Cemetery in Tripoli, Libya, Saturday, Dec., 17, 2011. Panetta visited the grave site of the sailors, who where killed on the USS Intrepid in 1804. (AP Photo/Pablo Martinez Monsivais, Pool)

U.S. Secretary of Defense Leon Panetta and Libyan Prime Minister Abd al-Rheem Al-Keeb greet one another during their joint news conference in Tripoli, Libya, Saturday, Dec., 17, 2011. (AP Photo/Pablo Martinez Monsivais, Pool)

U.S. Secretary of Defense Leon Panetta, second from left, leaves the grave site of 13 U.S. Navy sailors at the Protestant Cemetery in Tripoli, Libya, after participating in a wreath laying ceremony Saturday, Dec., 17, 2011. Panetta visited the grave site of the sailors, who where killed on the USS Intrepid in 1804. (AP Photo/Pablo Martinez Monsivais, Pool)

U.S. Secretary of Defense Leon Panetta, center, leaves his challenge coin on the grave stone during the wreath laying ceremony with U.S. Ambassador to Libya Gene Crets, obscured third from left, and Gen. Carter Ham, second from left, Commander U.S. Africa Command, at grave site of 13 U.S. Navy sailors at the Protestant Cemetery in Tripoli, Libya, Saturday, Dec., 17, 2011. Panetta visited the grave site of the sailors, who where killed on the USS Intrepid in 1804. (AP Photo/Pablo Martinez Monsivais, Pool)

U.S. Sec. of Defense Leon Panetta, left, is presented with a gift during his meeting with Libyan Minister of Defense Usama al-Jwayli, right, in Tripoli, Libya, Saturday, Dec. 17, 2011. (AP Photo/Pablo Martinez Monsivais, Pool)

TRIPOLI, Libya (AP) ? U.S. Defense Secretary Leon Panetta said "the torch of freedom" has passed to the Libyan people and he pledged during a historic visit Saturday to Tripoli that the United States will do all it can to help the country move toward democracy.

But he and his Libyan hosts acknowledged the threat of Islamic militants gaining ground in this period of political uncertainty following the ouster and death of longtime dictator Moammar Gadhafi.

Panetta and Libyan leaders identified challenges for the government now forming, including how to gain control of the militias that overthrew Gadhafi during an eight-month civil war.

"This will be a long and difficult transition, but I have confidence that you will succeed in realizing the dream of a representative government," Panetta said during a news conference with Prime Minister Abdurrahim el-Keib.

"The torch of freedom that has passed throughout the centuries and now passes from nation to nation in the Middle East and North Africa burns brightly here in Libya. May it light your way to a future of peace, prosperity and freedom," Panetta said.

While his visit was brief, Panetta made history as the first U.S. Pentagon chief to set foot on Libyan soil.

He evoked U.S. history, too, with a visit to the cemetery presumed to hold remains of U.S. sailors killed in Tripoli harbor in 1804. Their deaths were memorialized in the famous "shores of Tripoli" line in the Marine Corps hymn.

Both Panetta and al-Keeb expressed confidence that the fledgling government will be able to reach out to the militias and bring them together.

"We know how serious this issue is," said al-Keeb, "We realize it is not matter of saying 'OK, put down your arms, go back to work or do what you want to do.' We realize that there are lots of things that we need to be organized."

More broadly, Panetta said the revolts across the region represent a quest for sovereignty by the people, but they will all involve different approaches and challenges.

During meetings with the Libyan leaders, Panetta expressed concern about al-Qaida in the Islamic Maghreb militants gaining a foothold amid the chaos of an unfolding democracy. But they told him that the Libyan people will reject the terrorist group, said a senior defense official, who spoke on condition of anonymity because the discussions were private.

Panetta's motorcade from the airport into the city provided views of the nation's violent past and future promise ? lush orange groves, carcasses of bombed buildings and charred and graffiti-covered compound once occupied by Gadhafi. Flying from rooftops were the green, black and red flags, adorned with a star and a crescent, belonging to the new government.

At one point, amid the graffiti splashed across the walls of Gadhafi's former compound was a short comment in English: "Thanx US/UK."

The visit also put the man who has led much of the U.S. terrorism fight over the past several years at the scene of one of the first American wars on terror, more than two centuries ago.

Panetta went to what historians believe is the gravesite of as many as 13 U.S. sailors killed in 1804, when the Navy ship Intrepid exploded while slipping into Tripoli harbor to attack pirate ships that had captured an American frigate.

As the story goes, governments along the Barbary coast had turned to state-sponsored piracy to raise money, attacking and taking over merchant ships, enslaving their crews and stealing their bounties. Unwilling to pay fees to protect its ships, the U.S. sent the Navy frigate Philadelphia to the region but it ran aground just off Tripoli and was captured.

President Thomas Jefferson sent a team to get the Philadelphia back or destroy it. Under cover of darkness, the Intrepid sailed into the harbor, killed about 25 pirates and burned the Philadelphia.

A few months later, Jefferson sent the Intrepid back to destroy as many of the pirate ships as possible. The plan was to pack the ketch with explosives, sail into the harbor and blow her up.

The 13 sailors never got to their destination. The ship exploded prematurely killing all aboard and the next day bodies washed ashore. They were buried outside Tripoli, but in 1949 the remains were moved to The Protestant Cemetery by the Libyan government.

On Saturday, Panetta walked into the small walled cemetery and slowly made his way to a corner where five large but simple white gravestones mark the graves of the American sailors. Markers on four of the stones read, "Here lies an American sailor who gave his life in the explosion of the United States Ship Intrepid in Tripoli Harbour, Sept. 4, 1804."

Panetta placed a wreath at the site and, after a moment of silence, placed one of his U.S. secretary of defense souvenir coins on top of one of the stones.

New life was breathed into the long-ago tale by Congress this year. Lawmakers, prodded by descendants of the sailors, added provisions to the defense bill ordering the Pentagon to study the feasibility of exhuming the bodies and bringing them home to America.

In a statement, Panetta said the recent effort to restore the cemetery is "a symbol of the values we share."

Officials said that Panetta made no specific offers of assistance to the Libyan leaders, and he told reporters that there was no discussion of providing military equipment or weapons.

"They have to determine what their needs are and what kind of assistance is required," he said. "And whatever they need, the United States will be happy to respond."

Ahead of Panetta's visit, the Obama administration announced it had lifted penalties that were imposed on Libya in February to choke off Gadhafi's financial resources while his government was using violence to suppress peaceful protests.

The U.S. at the time blocked some $37 billion in Libyan assets, and a White House statement said Friday's action "unfreezes all government and central bank funds within U.S. jurisdiction, with limited exceptions."

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/3d281c11a96b4ad082fe88aa0db04305/Article_2011-12-17-US-Libya/id-5739c4ce08b94a6a92e6a26554db480c

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Varying Trends belonging to the Insurance Industry Market ...

Author name: Walter D.S. Ritts

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Source: http://www.iacapap2006.com/varying-trends-belonging-to-the-insurance-industry-market/

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Congo supreme court upholds president's victory

KINSHASA, Congo (AP) ? Congo's supreme court on Friday upheld President Joseph Kabila's victory following a contested election, raising fears of more violence in sub-Saharan Africa's largest nation because the main opposition candidate already has rejected the results showing he placed second.

The November election was only the second democratic vote in Congo's 51-year history, and the first to be organized by the Congolese government rather than by the international community. Observers have expressed concern about irregularities, saying voter turnout results were impossibly high in some districts.

Kabila, Congo's incumbent president, had faced 10 candidates, including Etienne Tshisekedi, a 79-year-old longtime opposition leader who is enormously popular with the country's impoverished masses. Observers fear unrest if Tshisekedi orders his supporters to take to the streets. So far, Tshisekedi has called for calm, telling his supporters to await his instructions.

Another opposition candidate, Vital Kamerhe, had appealed to Congo's supreme court to annul the presidential vote, but the court said late Friday that his complaint was groundless and lacked sufficient evidence. The decision was announced by Justice Jerome Kitoko, the court's vice president.

Kabila first came to power after his father's assassination and now has led the massive, mineral-rich Central African nation for a decade. Results released one week ago showed he had 49 percent of the vote, and Tshisekedi had 32 percent of the nearly 19 million votes cast.

Just 24 hours after those results were published, U.S. observers from the Atlanta-based Carter Center founded by former President Jimmy Carter issued a statement saying the vote lacked credibility.

David Pottie, one of the senior observers with the Carter Center, said it was impossible to have 100 percent voter turnout in a region where less than 2 percent of the roads are paved, and equally improbable for all the votes to go to Kabila, when there were 11 candidates on the ballot.

Country experts and opposition leaders originally had urged the government to delay the vote due to massive logistical problems. Instead, the poll went ahead although it was extended by several days so that more voters could cast ballots.

Congo sprawls across an area the size of Western Europe in the heart of Africa and neighbors nine other countries. Some districts of Congo, which suffered decades of dictatorship and two civil wars, are so remote that ballot boxes had to be transported across muddy trails on the heads of porters, and by dugout canoe across churning rivers.

The election took place amid significant unrest in Congo's east, where dozens of militia groups and rebels continue to terrorize people. Government soldiers and rebels have brutally raped women, men and children, and burned down villages. Hundreds of thousands of people have been forced to flee their homes because of violence.

The fighting is fueled by the competition to control mines, many operated by soldiers, rebels and militiamen who use the minerals to fund their armed groups.

(This version CORRECTS Corrects Tshisekedi's age to 79 to reflect his birthday this week.)

Associated Press

Source: http://hosted2.ap.org/APDEFAULT/cae69a7523db45408eeb2b3a98c0c9c5/Article_2011-12-16-AF-Congo-Election/id-3a29b9a7bb6d45549442a43570e093d6

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Biography of Simon Cowell set for spring release (omg!)

NEW YORK (AP) ? A biography of former "American Idol" judge Simon Cowell is coming soon.

Ballantine Books announced Thursday that it will publish Tom Bower's "Sweet Revenge: The Intimate Life of Simon Cowell" in the spring. According to Ballantine, an imprint of Random House Inc., Bower has had "hundreds of hours" of access to Cowell. The book will also include "direct contributions" from Cowell's friends and foes.

The acerbic Brit was a judge on Fox's "American Idol" for nine seasons. He left "Idol" to launch his British-born hit series "The X Factor" in the U.S. It debuted on Fox this fall.

Bower has written 19 books, including biographies of former British Prime Minister Gordon Brown and media mogul Conrad Black.

Source: http://us.rd.yahoo.com/dailynews/rss/entertainment/*http%3A//us.rd.yahoo.com/dailynews/external/omg_rss/rss_omg_en/news_biography_simon_cowell_set_spring_release153720770/43915892/*http%3A//omg.yahoo.com/news/biography-simon-cowell-set-spring-release-153720770.html

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RI economic summit leaders selected by SBA (AP)

PROVIDENCE, R.I. ? The leaders of several panels that will drive the discussion and make recommendations at an annual economic summit in Rhode Island next month have been announced by the U.S. Small Business Administration.

Among them are Grafton "Cap" Willey IV, who will chair the taxes and budget committee; Mark Deion, who will chair the economic development committee; and John Gregory, who will chair the workforce development and education committee. There are other panels on energy, health care and regulations.

The summit, in its sixth year, is sponsored by the Small Business Administration and the Rhode Island Small Business Development Center at Johnson & Wales University. It is taking place Jan. 27 at the university's Harborside campus.

Source: http://us.rd.yahoo.com/dailynews/rss/economy/*http%3A//news.yahoo.com/s/ap/20111214/ap_on_bi_ge/us_economic_summit_leaders_rhode_island

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