Now – print artificial bones on 3D
printer!
Washington, June 18 (ANI): Researchers have developed a
method, which helps them to print physical samples of artificial bones in just
a few hours. Associate professor Markus Buehler of the Department of Civil and
Environmental Engineering, MIT, and co-authors used computer-optimized designs
of soft and stiff polymers placed in geometric patterns that replicate nature’s
own patterns, and a 3-D printer that prints with two polymers at once.
The team produced samples of synthetic materials that have
fracture behaviour similar to bone and one of the synthetics is 22 times more
fracture-resistant than its strongest constituent material, a feat achieved by
altering its hierarchical design. Buehler said that the geometric patterns they
used in the synthetic materials are based on those seen in natural materials
like bone or nacre, but also include new designs that do not exist in nature.
The researchers created three synthetic composite materials,
each of which is one-eighth inch thick and about 5-by-7 inches in size. The
first sample simulates the mechanical properties of bone and nacre (also known
as mother of pearl). This synthetic has a microscopic pattern that looks like a
staggered brick-and-mortar wall: A soft black polymer works as the mortar, and
a stiff blue polymer forms the bricks.
Another composite simulates the mineral calcite, with an
inverted brick-and-mortar pattern featuring soft bricks enclosed in stiff
polymer cells. The third composite has a diamond pattern resembling snakeskin.
This one was tailored specifically to improve upon one aspect of bone’s ability
to shift and spread damage.
The team confirmed the accuracy of this approach by putting
the samples through a series of tests to see if the new materials fracture in
the same way as their computer-simulated counterparts. The samples passed the
tests, validating the entire process and proving the efficacy and accuracy of
the computer-optimized design. According to Buehler, the process could be
scaled up to provide a cost-effective means of manufacturing materials that
consist of two or more constituents, arranged in patterns of any variation
imaginable and tailored for specific functions in different parts of a
structure. He is hoping that eventually entire buildings might be printed with
optimized materials that incorporate electrical circuits, plumbing and energy
harvesting.
Source: http://health.india.com
20.06.2013
Obese children are likelier to
suffer hearing loss
Washington, June 18 (ANI): A new study has revealed that
obese adolescents are more likely than their normal-weight counterparts to have
hearing loss. Findings showed that obese adolescents had increased hearing loss
across all frequencies and were almost twice as likely to have unilateral (one-sided)
low-frequency hearing loss.
‘This is the first paper to show that obesity is associated
with hearing loss in adolescents,’ said study first author Anil K. Lalwani, MD,
professor and vice chair for research, Department of Otolaryngology/Head and
Neck Surgery, Columbia University Medical Center.
The study found that obesity in adolescents is associated
with sensorineural hearing loss across all frequencies (the frequency range
that can be heard by humans); sensorineural hearing loss is caused by damage to
the inner-ear hair cells.
The highest rates were for low-frequency hearing loss—15.16
percent of obese adolescents compared with 7.89 percent of non-obese
adolescents. People with low-frequency hearing loss cannot hear sounds in
frequencies 2,000 Hz and below; they may still hear sounds in the higher
frequencies (normal hearing range is from 20 Hz to 20,000 Hz). Often they can
still understand human speech well, but may have difficulty hearing in groups
or in noisy places.
‘These results have several important public health
implications,’ said Dr. Lalwani, who is also an otolaryngologist at
NewYork-Presbyterian Hospital/Columbia University Medical Center. ‘Because
previous research found that 80 percent of adolescents with hearing loss were
unaware of having hearing difficulty, adolescents with obesity should receive
regular hearing screening so they can be treated appropriately to avoid
cognitive and behavioural issues,’ he added. Dr. Lalwani and his
colleagues speculate that obesity may directly or indirectly lead to hearing
loss. Although additional research is needed to determine the mechanisms
involved, they theorize that obesity-induced inflammation may contribute to
hearing loss.
The study was recently e-published by The Laryngoscope, a
journal published by the American Laryngological, Rhinological and Otological
Society.
Source: http://health.india.com
20.06.2013
It is not only for what we do that we are held responsible, but also for
what we do not do
Moliere
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