TechKnowledgey 2005
to detect and validate infinitesimal amounts of the biomarkers in the blood.
In the first steps of the BCA process, special magnetic microparticles latch onto the biomarker targets (in this
study, the ADDLs). Researchers then add a second ingredient that consists of a gold nanoparticle core surrounded
by hundreds of identical DNA strands, which serve as
hundreds of bio-barcodes that are detected at the end of
the test.
Ultimately, the gold DNA particles and magnetic particles sandwich the biomarker targets. A magnet separates
the sandwiched complexes from the rest of the sample.
After which, the complexes are heated to release the DNA
bar codes, which are measured by an extremely sensitive
detector.
Each DNA piece greatly increases the sensitivity of
the test and its potential to tell doctors that a patient carries the ADDLs. Apparently, BCA is about one million
times more sensitive than the next best thing — standard enzyme-linked immunoassays (ELISAs). BCA
could eventually be configured to detect hundreds of
diseases simultaneously, including AIDS and prostate
cancer.
Computers and Networking
Tiny Flash Memory
The FinFET device stores one bit using
only 100 electrons, roughly equivalent
to the number contained in a single
gold atom. Photo courtesy of
Infineon Technologies.
Scientists at
Infineon
Technologies AG
have announced
construction of the
world’s smallest
nonvolatile Flash
memory cell,
measuring a mere
20 nm. Assuming
that all manufac-turing-related challenges (including
that of the lithography) can be
resolved, the development would make nonvolatile memory chips with a capacity of 32 GB possible within a
few years.
Nonvolatile Flash memories are commonly used as
mass storage media for devices such as digital cameras,
camcorders, and USB sticks. The most advanced nonvolatile Flash memory devices available today can permanently store one or two bits of information per memory cell
without a supply voltage. Such memories have a feature
size of around 90 nm, and significantly shrinking this feature size has posed many problems because of nanoscale
physical effects.
In particular, fabricating 20-nm, Flash memory cells
has been considered nearly impossible because these
APRIL 2005
physical effects would make the memory cells extremely
unreliable.
Infineon researchers overcame this challenge by creating a three-dimensional structure with a fin for the transistor that acts as the heart of the memory cell. The special
geometry minimizes unwanted effects and significantly
improves electrostatic control compared to today’s flat
transistors. Called a FinFET (fin field effect transistor), the
Infineon device stores the electrons that carry the information in a nitride layer that lies electrically isolated between
the silicon fin and the gate electrode. Just eight nm thin,
the fin is controlled by the 20-nm-wide gate electrode. The
devices won’t be commercially available for a few years,
but you can check on their progress at www.
infineon.com
Mac Mini
Back in days of yore (January 24, 1984, to be specific), Apple ( www.apple.com) introduced the original
Macintosh with a price of just under $2,500.00. Based on
the Consumer Price Index, this equals $4,555.00 in 2005
currency. For that, you got an 8-MHz processor, 128K
of RAM, no hard drive, and a built-in nine-inch
monitor. Storage was provided by a single 3.5-inch 400K
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