technology

Holding infants or not can leave traces on their genes

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The amount of close and comforting contact between infants and their caregivers can affect children at the molecular level, an effect detectable four years later, according to new research from the University of British Columbia and BC Children’s Hospital Research Institute.

The study showed that children who had been more distressed as infants and had received less physical contact had a molecular profile in their cells that was underdeveloped for their age — pointing to the possibility that they were lagging biologically.

“In children, we think slower epigenetic aging might indicate an inability to thrive,” said Michael Kobor, a Professor in the UBC Department of Medical Genetics who leads the “Healthy Starts” theme at BC Children’s Hospital Research Institute.

Although the implications for childhood development and adult health have yet to be understood, this finding builds on similar work in rodents. This is the first study to show in humans that the simple act of touching, early in life, has deeply-rooted and potentially lifelong consequences on genetic expression.

The study, published last month in Development and Psychopathology, involved 94 healthy children in British Columbia. Researchers from UBC and BC Children’s Hospital asked parents of 5-week-old babies to keep a diary of their infants’ behavior (such as sleeping, fussing, crying or feeding) as well as the duration of caregiving that involved bodily contact. When the children were about 4 1/2 years old, their DNA was sampled by swabbing the inside of their cheeks.

The team examined a biochemical modification called DNA methylation, in which some parts of the chromosome are tagged with small molecules made of carbon and hydrogen. These molecules act as “dimmer switches” that help to control how active each gene is, and thus affect how cells function.

The extent of methylation, and where on the DNA it specifically happens, can be influenced by external conditions, especially in childhood. These epigenetic patterns also change in predictable ways as we age.

Scientists found consistent methylation differences between high-contact and low-contact children at five specific DNA sites. Two of these sites fall within genes: one plays a role in the immune system, and the other is involved in metabolism. However, the downstream effects of these epigenetic changes on child development and health aren’t known yet.

The children who experienced higher distress and received relatively little contact had an “epigenetic age” that was lower than would be expected, given their actual age. Such a discrepancy has been linked to poor health in several recent studies.

“We plan on following up to see whether the ‘biological immaturity’ we saw in these children carries broad implications for their health, especially their psychological development,” says lead author Sarah Moore, a postdoctoral fellow. “If further research confirms this initial finding, it will underscore the importance of providing physical contact, especially for distressed infants.”

Event Horizon Telescope Reveals Magnetic Fields at Milky Way’s Central Black Hole

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Most people think of black holes as giant vacuum cleaners sucking in everything that gets too close.

But the supermassive black holes at the centers of galaxies are more like cosmic engines, converting energy from infalling matter into intense radiation that can outshine the combined light from all surrounding stars. If the black hole is spinning, it can generate strong jets that blast across thousands of light-years and shape entire galaxies. These black hole engines are thought to be powered by magnetic fields. For the first time, astronomers have detected magnetic fields just outside the event horizon of the black hole at the center of our Milky Way galaxy.

“Understanding these magnetic fields is critical. Nobody has been able to resolve magnetic fields near the event horizon until now,” says lead author Michael Johnson of the Harvard-Smithsonian Center for Astrophysics (CfA). The results appear in the Dec. 4th issue of the journal Science.

“These magnetic fields have been predicted to exist, but no one has seen them before. Our data puts decades of theoretical work on solid observational ground,” adds principal investigator Shep Doeleman (CfA/MIT), who is assistant director of MIT’s Haystack Observatory.

This feat was achieved using the Event Horizon Telescope (EHT) – a global network of radio telescopes that link together to function as one giant telescope the size of Earth. Since larger telescopes can provide greater detail, the EHT ultimately will resolve features as small as 15 micro-arcseconds. (An arcsecond is 1/3600 of a degree, and 15 micro-arcseconds is the angular equivalent of seeing a golf ball on the moon.)

Such resolution is needed because a black hole is the most compact object in the universe. The Milky Way’s central black hole, Sgr A* (Sagittarius A-star), weighs about 4 million times as much as our Sun, yet its event horizon spans only 8 million miles – smaller than the orbit of Mercury. And since it’s located 25,000 light-years away, this size corresponds to an incredibly small 10 micro-arcseconds across. Fortunately, the intense gravity of the black hole warps light and magnifies the event horizon so that it appears larger on the sky – about 50 micro-arcseconds, a region that the EHT can easily resolve.

The Event Horizon Telescope made observations at a wavelength of 1.3 mm. The team measured how that light is linearly polarized. On Earth, sunlight becomes linearly polarized by reflections, which is why sunglasses are polarized to block light and reduce glare. In the case of Sgr A*, polarized light is emitted by electrons spiraling around magnetic field lines. As a result, this light directly traces the structure of the magnetic field.

Sgr A* is surrounded by an accretion disk of material orbiting the black hole. The team found that magnetic fields in some regions near the black hole are disorderly, with jumbled loops and whorls resembling intertwined spaghetti. In contrast, other regions showed a much more organized pattern, possibly in the region where jets would be generated.

They also found that the magnetic fields fluctuated on short time scales of only 15 minutes or so.

“Once again, the galactic center is proving to be a more dynamic place than we might have guessed,” says Johnson. “Those magnetic fields are dancing all over the place.”

These observations used astronomical facilities in three geographic locations: the Submillimeter Array and the James Clerk Maxwell Telescope (both on Mauna Kea in Hawaii), the Submillimeter Telescope on Mt. Graham in Arizona, and the Combined Array for Research in Millimeter-wave Astronomy (CARMA) near Bishop, California. As the EHT adds more radio dishes around the world and gathers more data, it will achieve greater resolution with the goal of directly imaging a black hole’s event horizon for the first time.

“The only way to build a telescope that spans the Earth is to assemble a global team of scientists working together. With this result, the EHT team is one step closer to solving a central paradox in astronomy: why are black holes so bright?” states Doeleman.

Stronger hearts make women outlive men India

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Men have shorter lives than women because they are

more prone to heart disease, claims a new study that found
significant differences in life expectancies between the sexes
first emerged as recently as the turn of the 20th century.

Across the entire world, women can expect to live lo8nger
than men. Researchers wondered why does this occur and was
this always the case. According to the study, led by
researchers at the University of Southern California Davis
School of Gerontology, significant differences in life
expectancies between the sexes first emerged as recently as
the turn of the 20th century.

As infectious disease prevention, improved diets and other
positive health behaviours were adopted by people born during
the 1800s and early 1900s, death rates plummeted, but women
began reaping the longevity benefits at a much faster rate.

In the wake of this massive but uneven decrease in mortality,
a review of global data points to heart disease as the
culprit behind most of the excess deaths documented in adult
men, said USC University professor Eileen Crimmins. “We were
surprised at how the divergence in mortality between men and
women, which originated as early as 1870, was concentrated in
the 50-to-70 age range and faded out sharply after age 80.”
pti The study examined the life spans of people born between
1800 and 1935 in 13 developed nations.

Focusing on mortality in adults over the age of 40, the team
found that in individuals born after 1880, female death rates
decreased 70 per cent faster than those of males.

Even when the researchers controlled for smoking-related
illnesses, cardiovascular disease appeared to still be the
cause of the vast majority of excess deaths in adult men over
40 for the same time period.

Surprisingly, smoking accounted for only 30 per cent of the
difference in mortality between the sexes after 1890,
Crimmins said.

The uneven impact of cardiovascular illness-related deaths on
men, especially during middle and early older age, raises the
question of whether men and women face different heart
disease risks due to inherent biological risks and/or
protective factors at different points in their lives, said
USC University Professor Caleb Finch.

New Technology Colors In the Infrared Rainbow

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Researchers have devised a technology that can bring true color to infrared imaging systems, like the one used to track Arnold Schwarzenegger through the jungle in the movie “Predator.”
Traditional infrared imaging systems may look colorful on screen, with warm objects appearing redder and whiter than their surroundings. But these images are not created from actual colors.
They are based on the amount of thermal radiation&mdashor infrared light&mdashthat the camera captures.
The ability to identify different wavelengths&mdashor colors&mdashof the infrared spectrum would capture much more information about the objects being imaged, such as their chemical composition.
In a new study, a team lead by Maiken H. Mikkelsen, the Nortel Networks Assistant Professor of Electrical & Computer Engineering and Physics at Duke University, demonstrates perfect absorbers for small bands of the electromagnetic spectrum from visible light through the near infrared.
The fabrication technique is easily scalable, can be applied to any surface geometry and costs much less than current light absorption technologies.
Once adopted, the technique would allow advanced thermal imaging systems to not only be produced faster and cheaper than today’s counterparts, but to have higher sensitivity.
It could also be used in a wide variety of other applications, such as masking the heat signatures of objects.
“By borrowing well-known techniques from chemistry and employing them in new ways, we were able to obtain significantly better resolution than with a million-dollar state-of-the-art electron beam lithography system,” said Mikkelsen.
“This allowed us to create a coating that can fine-tune the absorption spectra with a level of control that hasn’t been possible previously, with potential applications from light harvesting and photodetectors to military applications.”
“This doesn’t require top-down fabrication such as expensive lithography techniques and we don’t make this in a clean room,” added Gleb Akselrod, a postdoctoral researcher in Mikkelsen’s laboratory.
“We build it from the bottom up, so the whole thing is inherently cheap and very scalable to large areas.”
The technology relies on a physics phenomenon called plasmonics.
The researchers first coat a surface with a thin film of gold through a common process like evaporation.
They then put down a few-nanometer-thin layer of polymer, followed by a coating of silver cubes, each one about 100 nanometers (billionths of a meter) in size.
When light strikes the new engineered surface, a specific color gets trapped on the surface of the nanocubes in packets of energy called plasmons, and eventually dissipates into heat.
By controlling the thickness of the polymer film and the size and number of silver nanocubes, the coating can be tuned to absorb different wavelengths of light from the visible spectrum to the near infrared.
“What is so attractive about the film/nanocube system is its remarkable simplicity and flexibility,” said David R. Smith, the James B. Duke Professor of Electrical and Computer Engineering at Duke.
“The unique absorbing properties of the nanocubes can be predicted with straightforward formulas, making it easy to quickly determine recipes for surface coatings that provide desired spectral properties.
The nanocube system eliminates, or at least vastly reduces, cost and manufacturing issues, so that we can focus on impacting exciting application areas such as photovoltaics or thermal coatings.”
For an example of the latter, if you can control the colors of light that a material absorbs, then you can also control the wavelengths of light that it emits.
By making the nanocubes larger to absorb wavelengths corresponding to thermal radiation, this technology could suppress or mask an object’s natural thermal radiation, otherwise known as “black body radiation.”
Coating photodetectors to absorb only specific wavelengths of infrared light would allow novel and cheap cameras to be made that could see different infrared colors. “We haven’t made the device that’s actually going to take that energy and convert it to an electrical signal yet,” said Akselrod.
“That’s going to be the next step.”