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First Responders
Ensuring
the Safety of First Responder Gas Masks
Firefighters
and other first responders faced with a terrorist attack soon
will breathe a little easier knowing that their gas masks have
been tested to ensure they work properly under emergency response
conditions.
Air purifying respirators, commonly known as gas masks, protect
workers from hazards associated with chemical, biological,
radiological and nuclear (CBRN) agents. The National Institute
of Standards
and Technology (NIST) has teamed up with the National Institute
for Occupational Safety and Health and the U.S. Army Soldier
and Biological Chemical Command to develop a full suite of
gas mask standards for civilian workers. The project is
funded by
the National Institute of Justice and the Centers for Disease
Control and Prevention.
Scientists will begin live agent testing of masks this spring
at the Army’s Aberdeen Proving Grounds in Maryland, one
of only a few nationwide laboratories that can do such tests
safely. The tests will ensure that the masks protect workers
from a mustard blistering agent and from the nerve gas sarin.
The tests are done on specially designed mannequins that can
precisely measure minute amounts of vapor that may penetrate
through the masks.
Masks worn by first responders must meet different standards
from those designed for troops. Most military uses involve
outdoor attacks where air currents would naturally disperse
chemicals
or other hazardous agents. The civilian testing procedures
address release of a hazardous agent inside buildings or
other closed
environments. The standard will include a maximum penetration
rate for hazardous substances and methods for testing the
fit of gas masks for individuals.
Dental Research
Tooth,
Heal Thyself
Dentists
beware: Teeth soon may be smart enough to fix themselves.
"
Smart materials” invented at the National Institute of Standards and
Technology (NIST) soon may be available that stimulate repair of defective
teeth. Laboratory
studies show that these composites, made of amorphous (loosely structured)
calcium phosphate embedded in polymers, can promote re-growth of natural tooth
structures
efficiently. In the presence of saliva-like solutions, the material releases
calcium and phosphate ions, forming a crystalline calcium phosphate similar
to the mineral found naturally in teeth and bone. Developed through a long-standing
partnership between NIST and the American Dental Association (ADA), these bioactive,
biocompatible materials are described in a forthcoming paper in the NIST
Journal of Research.
Plans
are being made for clinical trials, and several companies have
expressed interest in licensing the patented material
once a production-ready form is
available. Initial applications include adhesive cements that minimize the
decay that often
occurs under orthodontic braces. The material also can be used as an anti-cavity
liner underneath conventional fillings and possibly in root canal
therapy.
NIST and ADA scientists continue to enhance the material’s physicochemical
and mechanical properties and remineralizing behavior, thereby extending its
dental and even orthopedic applications. For example, the researchers found that
adding silica and zirconia to the material during processing stabilizes the amorphous
calcium phosphate against premature internal formation of crystals, thereby achieving
sustained release of calcium and phosphate over a longer period of time.
The work is funded through a grant from the National Institute
of Dental and Craniofacial Research.
Materials
Miniature
Mix-ups to Speed Materials Research
A new
National Institute of Standards and Technology (NIST) project
aims to stir up materials research by adapting “lab-on-a-chip” technology
to mix and evaluate experimental concoctions at a rapid clip,
hastening improvements in products ranging from paints to shampoos
to plastics.
Initially, researchers at the NIST Combinatorial Methods Center
(NCMC) and several of the NCMC’s company members plan to rev up the search for new or better
emulsions—often-complex formulations that are the basis for U.S. product
markets totaling more than $50 billion. They will start by deciphering interactions
at the interfaces (inter-facial tension) between the various components that
make up these viscous mixtures and are key to their performance.
Now, efforts to improve paints, shampoos and other emulsions
tend to be time-consuming, trial-and-error exercises.
But with tiny “lab-on-chip” devices, much
of the process can be automated, permitting rapid, systematic testing of new
material formulations.
The project will extend the capabilities of so-called microfluidic
systems—tiny,
channel-lined devices now used regularly for medical testing. In DNA chips,
for example, droplets of genetic material are routed
through networks of tiny wells,
each one set up for a particular diagnostic test. Material formulations,
however, typically contain
components—from solvents to different-sized
particles—that do not readily mix and circulate through these minute plumbing
systems. To accommodate these differences, NCMC researchers have designed and
tested credit-card-sized prototypes tailored for viscous materials research.
Features include mixers, pumps, reservoirs and computer control of the flow of
sample droplets through a network of millimeter-wide channels. Mixture properties
will be characterized with real-time image measurement techniques that NIST is
developing with an eye on many application areas.
