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A new Nanowerk Spotlight "Nanotechnology is key to next-generation tissue
and cell engineering" is available on the Nanowerk website at
http://www.nanowerk.com/spotlight/spotid=2434.php In the medical field
there is a huge demand for tissue regenerationtechnologies, which covers
a wide range of potential applications in suchareas as cartilage, vascular,
bladder and neural regeneration. Just considerthe need for bone and dental
implants: Each year, almost 500,000 patientsreceive hip implants worldwide,
about the same number need bonereconstruction due to injuries or congenital
defects and 16 millionAmericans loose teeth and may require dental implants. The market formedical implant devices in the U.S. alone is estimated to be $23 billion peryear and it is expected to grow by about 10% annually for the next fewyears. Unfortunately, medical implant devices have been associated with avariety of adverse reactions, including inflammation and fibrosis. It hasbeen suggested that poor tissue integration is responsible for loosening ofimplants and mechanical damage to the surrounding host tissues. Based on anexpanding body of biomedical nanotechnology research work, there is agrowing consensus among scientists that nanostructured implant materials mayhave many potential advantages over existing, conventional ones. The key, asindicated in a number of findings, seems to be that physical properties ofmaterials, especially with regard to their surface's nanostructure, affectcell attachment and eventually the tissue response to the implant. Althoughnanotopography mediated cell responses have been shown in previous work, themechanism of these responses is mostly
undetermined. New research has nowbeen conducted to determine the influence
of nanopore size on cellularresponses. Interestingly, these studies have
revealed that larger nanopores(200 nm) trigger DNA replication and cell
proliferation via various signaltransduction pathways.
A new Nanowerk Spotlight "Nanoelectromechanical systems start to take shape"
is available on the Nanowerk website at http://www.nanowerk.com/spotlight/spotid=2431.php
In his famous 1959 speech "Plenty of Room at the Bottom", Richard Feynmanoffered
a prize of $1000 "to the first guy who makes an operating electricmotor -
a rotating electric motor which can be controlled from the outsideand,
not counting the lead-in wires, is only 1/64 inch cube." Feynman hadhoped
his reward would stimulate some new fabrication technology but he wasquite
consternated when one year later, Bill McLellan, using amateur radioskills,
built the motor with his hands using tweezers and a microscope (andmany, many
hours of fiddling around). McLellan's 2000 rpm motor weighed 250micrograms
and consisted of 13 parts. In the almost 50 years since, not onlyhas the
field of microelectromechanical systems (MEMS) caught up withFeynman's bet
and achieved commercial production capabilities of motors manytimes smaller
than McLellan's, but researchers have begun exploring anotherlevel of
miniaturization - nanoelectromechanical systems (NEMS). Efficientactuation,
the creation of mechanical motion by converting various forms ofenergy to
rotating or linear mechanical energy, is an important - and todaystill
frustrating - issue in designing NEMS. Research on building functionalnanoscale
electromechanical systems is well underway, as just demonstratedwith another
achievement by scientists at Caltech - the place where Feynmangave his speech
and McLellan's motor still is on display.
A new Nanowerk Spotlight "Wet nanotechnology - living transistors with
nanofluidic diodes" is available on the Nanowerk website at
http://www.nanowerk.com/spotlight/spotid=2403.php Ion channels are
proteins with a hole down their middle that are thegatekeepers for cells.
Ion channels control an enormous range of biologicalfunction in health
and disease. In channels with a diameter greater than 100nm, the interaction
between the channel wall and electrolyte solution hardlyaffects the flow
of ions. When the channel diameter enters the the <10 nmrange, things
change dramatically, however. Then, the interaction betweenthe solution
and channel wall starts to dominate ionic flow and iontransport through
such narrow, nano-scaled channels is dominated byelectrostatics. The
same is true for biological ion channels where chargedamino residues
in the selectivity filter determine the ionic flow throughthe channel,
along with the dielectric charge on the channel wall, and theconcentrations
and potential in the bulk solution. The role electrostaticsplay in biological
pores has been confirmed by numerous mutation studieswhere amino acids
residues in the selectivity filter were replaced byothers. Ion channels
have simple enough structure that they can be analyzedwith the usual tools
of physical science. With that analysis in hand,researchers are trying to
design practical machines that use ion channels.By exploiting the
electrostatics in nanochannels a group of US and Dutchscientists managed
to make a diode. Like a solid-state diode allows currentflow in one
direction, the ionic equivalent they designed can be used todirect the
flow of ions across a membrane that separates two electrolytesolutions.
Now that they know how to manipulate the ion selectivity in thesedevices,
they hope to be able one day to selectively amplify currentscarried by
individual chemical species - a stunning prospect for
molecularnanoelectronics.
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Sponsor: InMage Systems, Inc.
If growing amounts of data files and government regulations are straining your storage, backup, and data recovery efforts, then we invite you to hear what the experts are saying about a strategic, new approach to data protection. Go now! |
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| :: EDITOR'S NOTE :: August 15, 2007 |
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| Municipal Wi-Fi projects have lost some of their luster over recent months. But a new focus on their potential role in public safety could help in making the case. |
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| Municipal Wi-Fi Rationale Shifting |
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Are municipal wireless projects better positioned as primarily infrastructure to aid government and business or consumers and tourists? Of course, an existing network — no matter who it primarily serves on a normal day — can be put to good use in an emergency. We're not too sure how great the technical differences are between the two approaches. The point is that the distinction can be vital during the critical funding phase. It's instructive to examine the story of how the subsidiary of U.S. Internet that is working on Wireless Minneapolis pitched in when a bridge spanning the Mississippi collapsed. As the tragedy unfolded, the subsidiary disabled the network's paid log-in process, thus making connectivity freely available. Within hours, about six times the normal 1,000 paid users were on the system.
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:: INSIGHTS FROM AROUND THE WEB ::
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| Free White Papers: Network Security |
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| :: Executive Briefing :: |
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| Get Ready for the Mobile Data Explosion |
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Nobody doubts that mobile data services and applications will grow in value for the foreseeable future. ABI principal analyst Dan Shey has written a report that both puts a price tag on the services — $100 billion in worldwide revenue by 2012 — and creates a framework for thinking about the applications and their uses in order to determine the source of the growth.
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