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Friday, October 17, 2008

Centrosome misorientation reduces stem cell division during ageing

Jun Cheng1,5, Nezaket Türkel2,5,6, Nahid Hemati2,5, Margaret T. Fuller4, Alan J. Hunt1 & Yukiko M. Yamashita2,3

1. Department of Biomedical Engineering, Center for Ultrafast Optical Science
2. Life Sciences Institute, Center for Stem Cell Biology,
3. Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan 48109, USA
4. Departments of Developmental Biology and Genetics, Stanford University, School of Medicine, Stanford, California 94305, USA
5. These authors contributed equally to this work.
6. Present address: Peter MacCallum Cancer Centre, Anatomy and Cell Biology Department, University of Melbourne, Melbourne, Victoria 3002, Australia.

Correspondence to: Yukiko M. Yamashita2,3 Correspondence and requests for materials should be addressed to Y.M.Y. (Email: yukikomy@umich.edu).

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Abstract

Asymmetric division of adult stem cells generates one self-renewing stem cell and one differentiating cell, thereby maintaining tissue homeostasis. A decline in stem cell function has been proposed to contribute to tissue ageing, although the underlying mechanism is poorly understood. Here we show that changes in the stem cell orientation with respect to the niche during ageing contribute to the decline in spermatogenesis in the male germ line of Drosophila. Throughout the cell cycle, centrosomes in germline stem cells (GSCs) are oriented within their niche and this ensures asymmetric division. We found that GSCs containing misoriented centrosomes accumulate with age and that these GSCs are arrested or delayed in the cell cycle. The cell cycle arrest is transient, and GSCs appear to re-enter the cell cycle on correction of centrosome orientation. On the basis of these findings, we propose that cell cycle arrest associated with centrosome misorientation functions as a mechanism to ensure asymmetric stem cell division, and that the inability of stem cells to maintain correct orientation during ageing contributes to the decline in spermatogenesis. We also show that some of the misoriented GSCs probably originate from dedifferentiation of spermatogonia.

No more third time lucky

NIH clamps down on proposal resubmissions.

Heidi Ledford

The US National Institutes of Health (NIH) announced last week that biomedical researchers will be able to amend and resubmit a failed funding application only once. Applicants whose grants are unfunded after the second submission may reapply only after designing a new proposal.

New law threatens Italian research jobs

Scientists protest over government's cost cutting.

Emiliano Feresin & Alison Abbott

Nearly 2,000 Italian researchers will lose promised permanent positions under a law that is expected to come into force by the end of the year. They may have to leave public research altogether.

Computer circuit builds itself

Organic molecules organize themselves to form a bridge between electrodes.

Geoff Brumfiel
Flexible circuitsComputer circuits made from organic molecules could be used to build lightweight, flexible displays.ASSOCIATED PRESS

A team of European physicists has developed an integrated circuit that can build itself. The work, appearing in this week's Nature1, is an important step towards its ultimate goal — a self-assembling computer.

Today's computer chips are made by etching patterns onto semiconducting wafers using a combination of light and photosensitive chemicals. But the technique is being pushed to the limit as ever more processing power is being packed onto chips, requiring engineers to etch details just a few tens of nanometres across. So scientists are hunting for alternative ways to assemble even tinier chips.

“We dump it in a beaker with a solution of the molecules, we take it out, we wash it, and it works.”

Dago de Leeuw
Philips Research Laboratories, the Netherlands

Letting them build themselves is, in many ways, the most obvious solution, says Dago de Leeuw, a researcher at Philips Research Laboratories in Eindhoven, the Netherlands. "The nicest example is DNA," he says. Our genetic code provides a set of instructions that can be used to marshal molecules into an entire person, and researchers would like to come up with a similar set of compounds able to organize each other into circuits.

That's no small task. To make a circuit that is truly self-assembling, physicists would need to get insulators, conducting electrodes and semiconductor transistors to all link to each other automatically — something that is still a long way away, says de Leeuw.
Chip 'n dip

But his team has made an important step. They took a long organic molecule with mobile electrons, called quinquethiophene, that behaves like a semiconductor and attached it to a long carbon chain with a silicon group at the end, which acts an an anchor.

“Self-assembly and nanotechnology is certainly cool, but the one thing missing is higher performance.”

Hagen Klauk
Max Planck Institute for Solid State Research, Germany

The researchers then dunked a circuit board with preprinted electrodes into a solution of their new molecules. The molecules hooked on to an insulating layer between the electrodes, forming bridges from one electrode to the next. It took billions to make the connection, but they were tightly packed enough that a current could flow across them. "The different molecules are like little bricks," says Edsger Smits, another researcher at Philips. "Frankly it worked much better than we expected."

The team used the technique to construct a simple circuit that generates a code based on an input voltage. Although the system depends on the preprinted electrodes to act as a template, the circuit is truly self-assembling, says de Leeuw: "We dump it in a beaker with a solution of the molecules, we take it out, we wash it, and it works."

The new technique is impressive but still needs improvement, says Hagen Klauk, an electrical engineer at the Max Planck Institute for Solid State Research in Stuttgart, Germany. "Self-assembly and nanotechnology is certainly cool, but the one thing missing is higher performance," he says. The mobility of electrons through the circuit, he explains, means that the transistors would make for a very slow computer.

Klauk hopes that improving the characteristics of the molecules and tweaking the technique will eventually lead to self-assembling circuits that out-perform existing technologies, which use thick films of organic molecules.

For his part, de Leeuw says the next step will be figuring out a way to develop self-assembling electrodes. In the meantime, however, he says the group's circuits may already have a use. Because the bridge of molecules is very thin, it is extraordinarily sensitive to passing particles. The team believes that it could be used to develop sensors for different kinds of airborne material, such as pathogens or dangerous chemicals.

Thursday, October 16, 2008

Flying The Anti-Porn Skies

Violet Blue wants to know, if airline Wi-Fi is censored, who wants it?

Getting ready for my latest flight out of SFO, I ran down my checklist of must-have carry-on items in my bag. For the long flight to Los Angeles, I'd need a 16 oz. bottle of Liquid Silk, latex gloves, my raincoat, my Vibrating Hugh Jackman Realistic Dong, a pack of ten C batteries, my trusty fur-lined leopard ankle cuffs, and a blindfold. The blindfold was for napping. Since my airline now sells in-flight Wi-Fi, I could add my laptop to the list, eschew all the DVDs I usually lug on the plane, and instead of watching "Penetration Impossible #4," I'd be flying the friendly skies crammed between my seat-mates and cruising the latest videos uploaded to YouPorn.com. After checking my e-mail, Twittering a complaint about the overpriced Wi-Fi, doing a guest blog post for Laughing Squid about the overpriced Wi-Fi and watching the Dow have another bipolar episode, of course.

I am a porn consumer. And from San Francisco, it's like a double-whammy of pervery; everyone knows we porn users just can't control ourselves. Thank goodness the airlines - despite having no complaints of porn being accessed over their new Wi-Fi services - are preemptively blocking and blacklisting Web sites. Otherwise, my flight would be a trip to hell in the skies for everyone sitting next to one of us porn watchers, because, you know, all that online porn consumption makes us into drooling lunatics who no longer know right from wrong.

At least that seems to be the logic when you peel back the layer of reason behind American Airlines' recent decision to reverse their originally stated no-filtering policy for in-flight Wi-Fi and announce that they'll be implementing "technology" to filter pornographic content over its Gogo Internet service. Seeing that on the Gogo Web site they also have Air Canada, Delta and Virgin Airlines listed as upcoming partners, we can expect to be nannied from here to Internet infinity so no one in the seats behind you have to tell you to turn down the volume on your VoD stream of "White Men Can't Hump." Which, if you've seen it, gives new meaning to the concept of "red eye flight."

Despite the fact that there haven't been any complaints thus far, the Association of Flight Attendants is hailing the decision they see as one less thing they have to police on board, and it makes sense - until you think about the fact that people can have and view porn on their computers even without access to the evil scary child-eating unfiltered Internet, or a European fashion magazine could have more exposed sexy nipples than erosblog.com and thesexcarnival.com rubbed together. Or that someone might - gasp! - read a book. One with sexual or pornographic content. There are so few of those out there. At least we can rest easy on our "comfortable flight" safe in the knowledge that no one reads books anymore.

Poking holes in filtering Internet Wi-Fi access as a strategy to prevent in-flight inappropriateness is easy enough, but looking at the implementation of Wi-Fi censorware will make even the sweetest sexy librarian want to throw the book at the Association of Flight Attendants. Historically, filtered Internet access doesn't have a very good track record with subjects like sexual health Web sites (including the famously filtered breast cancer Web site kerfluffle), nor a healthy relationship with LGBT and sexual minority Web sites. And when you think that just last year Google's AdWords was putting sites with the reclaimed word "dyke" in the child porn bucket by accident, you're going to have a lot more incidents of air rage on your hands when the businessperson who just paid $12.95 plus fees for a few hours of access can't find the address of the non-porn business they're supposed to go to when they land. Or can't work remotely because their company's Web site (or blogging interface) is inexplicably blocked. Or, we just all get cranky because we can't visit our favorite entertainment blog because it once flashed a nipple or reported on an obscenity case, triggering the nannyware to auto-blacklist it.

Of course, the sensible thing to do would be to tell customers at point of purchase that they're getting only part of the Internet for their dollars (or one Euro), and provide a list of sites they won't be able to access before they click "submit payment." But then again, we're talking about an airline that just banned Internet phone service Skype for no real reason other than because it competed with airlines' own expensive in-flight phone services. Talk about nonconsensual power play; I guess that's great if your fetish is being a captive consumer.

It's not just the shady peepshow-style implementation of the Wi-Fi filtering that's got my airline dollars feeling a little shrinkage from the cold eye on my browsing habits; it's the people pimping the notion of filtering to the airlines in the first place. According to Wired, "Girls Against Porn lobbied American to install filters, urging the airline to consider the harm inappropriate content might have on passengers and citing a particularly disgusting incident that has resulted in a $200,000 lawsuit against American (Airlines). 'The airlines risk having this happen repeatedly if the Internet isn't filtered,' Girls Against Porn said in a statement." And the Texas Star-Telegram tells us that, "(...) several groups, including the conservative Christian group Focus on the Family, expressed concerns that children could be exposed to pornographic Web sites by adjacent passengers. Daniel Weiss, an analyst for media and sexuality at Focus on the Family Action, recently warned in a statement that "passengers who openly view porn where children can see it may be violating federal harmful-to-minor laws."

Never mind that the "particularly disgusting incident" where a male passenger masturbated into a female passenger's hair while she slept had absolutely nothing to do with porn. It's that because there was a sexual incident, and that sex is bad and shameful and porn is as evil as any sexual violation, that by its very nature these anti-porn groups can discredit anything sexual by nature of its very existence. Taking for granted the hurtful myths about porn consumption is the easiest way to masturbate in the dark all over any conversation regarding adult choices and consumer freedom.

Lest we forget that the point of filterware is to limit or prevent viewers from accessing anything the Wi-Fi provider considers objectionable and frequent subjects of content-control include not just sex and queer Web sites, but also topics considered "immoral", sites that discuss religion, health and politics and possibly more. This isn't a spam blocker, this is something that doesn't let you see what the authority doesn't want you to - or, whoever's pressuring them, such as the nightmare-inducing CP80 - backing anti-porn all-women-are-victims GAP or the notoriously tolerant Focus On The Family. FotF, who markets the lovely CYBERsitter filtering software that handily, blocks the National Organization for Women homepage (and any Yahoo Web search for "gay rights"). Filtering for moral or political reasons, much?

Yes, the airlines are businesses and we don't have to buy their crappy Wi-Fi. And maybe there's something inherently hot about being treated like a criminal for simply being a normal porn consumer, despite the fact that we prefer our porn behind closed doors and not while packed like cattle into overpriced seats. But next time I'm on Virgin America and I see the safety video with a two-second image of a bull sitting next to a matador, while the matador gets his seat belt figured out, and the bull is plainly reading a magazine with bright pink exposed udders on it - I really hope I can control myself. Because you know I'll have the Guy Ritchie blowup doll in my purse, ready for takeoff.

Web Video Marketing TV™ Opening Local Marketing Offices Nationwide

Channels Network TV announced today that they will begin opening local offices of their business video marketing division Web Video Marketing TV in major cities throughout the nation. The local offices of Web Video Marketing TV will provide all businesses and professionals with expert business video marketing and search optimization services that rank as among the best in the world.

Web Video Marketing TV http://webvideomarketing.tv has the unique expertise that can only come from being a subsidiary of Channels Network TV, a company with a history of e-commerce success, e-business success and superior search engine optimization and search marketing since 1995. Channels Network TV is the first to develop and launch the first of its’ kind video based network of websites that showcase every business and profession in the nation on Business Intros TV http://businessintros.tv and Biz Intros TV business web portals, and niche video business portal that showcase attorneys, car dealers, internet car dealers, hotels, and restaurants nationwide.

Business web video marketing has quickly become the advertising and marketing medium of choice for all businesses, and business video directories are where all businesses and professionals need to post their videos for maximum web exposure. The viral nature of web video produces tremendous marketing results at a price far below any other advertising or marketing.

Web Video Marketing TV local offices will provide all area businesses and professionals with proven business web video marketing that will immediately put these businesses before the eyes of tens of thousands of unique visitors everyday. Because Web Video Marketing TV is the industry pioneer in business video marketing, only they can provide any business with video marketing success by illustrating their own search video marketing organic search positioning which often ranks number one, two, or three on the first page of natural search.

The Web Video Marketing TV offices will be owned and operated by local entrepreneurs who will also be the exclusive local sales agents for the many business video websites that make up Channels Video Network. The owners of the local Web Video Marketing TV will receive comprehensive training to prepare to provide the highest level of video marketing services. The local agency offices will operate in conjunction with Channels Video Network through an exclusive joint venture agreement where the local agent provides sales and customer service and Channels Video Network provides the web infrastructure, technical services, and all other aspects of web operations.

McCain caught in DMCA flap

YouTube denies special treatment to candidate

Written by Shaun Nichols in San Francisco

Video-sharing site YouTube has declined to give special treatment to Republican presidential candidate John McCain over digital millenium copyright act (DMCA) claims.

In an exchange of letters, the site and McCain's campaign staff engaged in a debate over the controversial law, which requires web sites to take down content which contains copyrighted material at the request of the copyright holder in order. McCain voted to approve the DMCA in 1998.

The issue surrounds campaign videos produced by McCain which contained clips from broadcasts by Fox News. The network contended that McCain was illegally using is copyrighted broadcasts in the advertisements and filed a DMCA claim to have the video clips removed from the internet.

McCain's campaign sent a letter to YouTube asking the site to allow the clips to remain online while it was determined whether the videos constituted fair use, a series of protections which allows individuals to use copyrighted clips under certain circumstances. Earlier this year, US courts decided that copyright holders had the responsibility to consider fair use before filing a DMCA takedown claim.

The campaign contended that because the clips were brief and non-commercial in nature, they fell under the protections of fair use and as such should not be removed. The letter also suggested that the site extend special protections to political campaigns which would allow for a more thorough review before clips could be removed due to a DMCA claim.



YouTube countered in a letter contending that if the site complied with the campaign's request, it could lose the DMCA protections which shield sites from lawsuits. The site also said that, given the amount of video uploads it receives on a regular basis, it could not make special concessions to isolate and protect campaign videos.

"The fact remains that we do not know who uploaded what content in user vid eos, who uploaded the videos or what authorization the uploader may or may not have to use that content," read the letter.

"Moreover, while we agree with you that the US presidential election-related content is invaluable and worthy of the highest level of protection, there is a lot of other content on our global site that our users find to be equally important, including political campaigns from around the world at all levels of government, human rights movements, and other important voices."

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