From UCLA Newsroom: “Researchers convert 2D images into 3D using deep learning”


From UCLA Newsroom

November 7, 2019
Nikki Lin
310-206-8278
nlin@cnsi.ucla.edu

1
Illustration represents Deep-Z, an artificial intelligence-based framework that can digitally refocus a 2D fluorescence microscope image (at bottom) to produce 3D slices (at left). Ozcan Lab/UCLA.

A UCLA research team has devised a technique that extends the capabilities of fluorescence microscopy, which allows scientists to precisely label parts of living cells and tissue with dyes that glow under special lighting. The researchers use artificial intelligence to turn two-dimensional images into stacks of virtual three-dimensional slices showing activity inside organisms.

In a study published in Nature Methods, the scientists also reported that their framework, called “Deep-Z,” was able to fix errors or aberrations in images, such as when a sample is tilted or curved. Further, they demonstrated that the system could take 2D images from one type of microscope and virtually create 3D images of the sample as if they were obtained by another, more advanced microscope.

“This is a very powerful new method that is enabled by deep learning to perform 3D imaging of live specimens, with the least exposure to light, which can be toxic to samples,” said senior author Aydogan Ozcan, UCLA chancellor’s professor of electrical and computer engineering and associate director of the California NanoSystems Institute at UCLA.

In addition to sparing specimens from potentially damaging doses of light, this system could offer biologists and life science researchers a new tool for 3D imaging that is simpler, faster and much less expensive than current methods. The opportunity to correct for aberrations may allow scientists studying live organisms to collect data from images that otherwise would be unusable. Investigators could also gain virtual access to expensive and complicated equipment.

This research builds on an earlier technique Ozcan and his colleagues developed that allowed them to render 2D fluorescence microscope images in super-resolution. Both techniques advance microscopy by relying upon deep learning — using data to “train” a neural network, a computer system inspired by the human brain.

Deep-Z was taught using experimental images from a scanning fluorescence microscope, which takes pictures focused at multiple depths to achieve 3D imaging of samples. In thousands of training runs, the neural network learned how to take a 2D image and infer accurate 3D slices at different depths within a sample. Then, the framework was tested blindly — fed with images that were not part of its training, with the virtual images compared to the actual 3D slices obtained from a scanning microscope, providing an excellent match.

Ozcan and his colleagues applied Deep-Z to images of C. elegans, a roundworm that is a common model in neuroscience because of its simple and well-understood nervous system. Converting a 2D movie of a worm to 3D, frame by frame, the researchers were able to track the activity of individual neurons within the worm body. And starting with one or two 2D images of C. elegans taken at different depths, Deep-Z produced virtual 3D images that allowed the team to identify individual neurons within the worm, matching a scanning microscope’s 3D output, except with much less light exposure to the living organism.

The researchers also found that Deep-Z could produce 3D images from 2D surfaces where samples were tilted or curved — even though the neural network was trained only with 3D slices that were perfectly parallel to the surface of the sample.

“This feature was actually very surprising,” said Yichen Wu, a UCLA graduate student who is co-first author of the publication. “With it, you can see through curvature or other complex topology that is very challenging to image.”

In other experiments, Deep-Z was trained with images from two types of fluorescence microscopes: wide-field, which exposes the entire sample to a light source; and confocal, which uses a laser to scan a sample part by part. Ozcan and his team showed that their framework could then use 2D wide-field microscope images of samples to produce 3D images nearly identical to ones taken with a confocal microscope.

This conversion is valuable because the confocal microscope creates images that are sharper, with more contrast, compared to the wide field. On the other hand, the wide-field microscope captures images at less expense and with fewer technical requirements.

“This is a platform that is generally applicable to various pairs of microscopes, not just the wide-field-to-confocal conversion,” said co-first author Yair Rivenson, UCLA assistant adjunct professor of electrical and computer engineering. “Every microscope has its own advantages and disadvantages. With this framework, you can get the best of both worlds by using AI to connect different types of microscopes digitally.”

Other authors are graduate students Hongda Wang and Yilin Luo, postdoctoral fellow Eyal Ben-David and Laurent Bentolila, scientific director of the California NanoSystems Institute’s Advanced Light Microscopy and Spectroscopy Laboratory, all of UCLA; and Christian Pritz of Hebrew University of Jerusalem in Israel.

The research was supported by the Koç Group, the National Science Foundation and the Howard Hughes Medical Institute. Imaging was performed at CNSI’s Advanced Light Microscopy and Spectroscopy Laboratory and Leica Microsystems Center of Excellence.

See the full article here .


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Please help promote STEM in your local schools.

Stem Education Coalition

UC LA Campus

For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

#researchers-convert-2d-images-into-3d-using-deep-learning, #applied-research-technology, #deep-learning, #deep-z-is-an-artificial-intelligence-based-framework-that-can-digitally-refocus-a-2d-fluorescence-microscope-image-to-produce-3d-slices, #ucla

From UCLA and From Arizona State University via Science Alert: “Engineers Create Tiny ‘Artificial Sunflowers’ That Bend Towards The Light”

UCLA bloc

From UCLA

and

ASU Bloc

From Arizona State University

via

ScienceAlert

Science Alert

6 NOV 2019
MIKE MCRAE

1
(Qian et al., Nature Nanotechnology, 2019)

When it comes to squeezing maximum amounts of energy out of the daylight hours, plants have a head start thanks to evolution.

Now, engineers have designed solar panels that mimic the sunflower’s sun-chasing talent, through clever use of nanotechnology.

By moulding temperature-sensitive materials into thin, supportive structures, scientists have come up with tiny ‘stems’ that bend towards a bright light source, providing a moving platform that could dramatically improve the efficiency of a range of solar technologies.

Researchers from the University of California Los Angeles and Arizona State University refer to their system as a sunflower-like biomimetic omnidirectional tracker. Or ‘SunBOT’, if you like your acronyms.

In biological terms, any general movement in response to specific changes in the environment is described as a nastic behaviour. Flowers that open at dawn and close at dusk are a good example of this.

Chemists have had little trouble making synthetic nastic materials [International Journal of Smart and Nano Materials] and structures that open and close, or bend and twist in response to changes in light intensity or fluctuating temperatures.

But nature has another, slightly more complicated behaviour that directs the movements of organisms towards good things and away from threats.

These tropic behaviours are what we see when sunflowers tilt their flowers to face the Sun, warming their reproductive bits [Science ABC] in order to attract pollinators.

Sun-chasing actions, or heliotropism, would be mighty handy for things like photovoltaics, which are most efficient when bathed in a dense glow of radiation hitting their surface straight-on, rather than from a more shallow angle.

In practical terms, compared to rays from an overhead illumination source, light coming in at an angle of around 75 degrees carries as much as 75 percent less energy.

To solve this problem of oblique-incidence energy-density loss, the research team looked to gels and polymers that respond predictably to light or heat.

A handful of different materials were selected as candidates worth closer investigation, including a hydrogel containing gold nanoparticles, a tangle of light-sensitive polymers, and a type of liquid crystalline elastomer embedded with a light-absorbing dye.

Each arrangement was shaped into a millimetre-wide thread several centimetres in length. When targeted by a laser, the tiny artificial stalks responded rapidly to the light’s warmth, shrinking on one side and expanding on the other to cause the thread to kink and lean towards the laser.

To put their synthetic sunflowers to the test, the researchers assembled an array of SunBOTs and submerged them in water, letting them sit right at the water-air boundary.

To detect the harvesting capabilities of their invention, the team then determined how much light was converted to heat by measuring the water vapour their setup generated.

Changes in the amount of vapour indicated that the SunBOTs were up to four times better at harvesting energy at steep angles than a boring old flat, static surface.

By demonstrating that a variety of materials could serve as a synthetic tropic material, the researchers argue their devices could potentially be a solution for just about any system that experiences a loss of efficiency due to a moving energy source.

For example, lawns of these miniature sun-worshippers could theoretically be used to tilt just about any solar process towards the light, from itty-bitty solar cells to evaporation devices that can purify water.

According to the SunBOTs’ designers, the sky (if not beyond!) seems to be the limit for this kind of technology.

“This work may be useful for enhanced solar harvesters, adaptive signal receivers, smart windows, self-contained robotics, solar sails for spaceships, guided surgery, self-regulating optical devices, and intelligent energy generation (for example, solar cells and biofuels), as well as energetic emission detection and tracking with telescopes, radars and hydrophones,” they write in their report.

Even if just a handful of those predictions eventuates into real-world use, the future of synthetic tropic materials is certainly looking brighter.

This research was published in Nature Nanotechnology.

See the full article here .

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Please help promote STEM in your local schools.

Stem Education Coalition

ASU is the largest public university by enrollment in the United States. Founded in 1885 as the Territorial Normal School at Tempe, the school underwent a series of changes in name and curriculum. In 1945 it was placed under control of the Arizona Board of Regents and was renamed Arizona State College. A 1958 statewide ballot measure gave the university its present name.
ASU is classified as a research university with very high research activity (RU/VH) by the Carnegie Classification of Institutions of Higher Education, one of 78 U.S. public universities with that designation. Since 2005 ASU has been ranked among the Top 50 research universities, public and private, in the U.S. based on research output, innovation, development, research expenditures, number of awarded.

UC LA Campus

For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

#engineers-create-tiny-artificial-sunflowers-that-bend-towards-the-light, #applied-research-technology, #asu, #heliotropism, #nanotechnology, #science-alert, #sunbots, #the-research-team-looked-to-gels-and-polymers-that-respond-predictably-to-light-or-heat, #ucla

From UCLA: “Ancient stars shed light on Earth’s similarities to other planets”

UCLA bloc

From UCLA

October 17, 2019
Stuart Wolpert

1
An artist’s rendering shows a white dwarf star with a planet in the upper right. Mark Garlick

Earth-like planets may be common in the universe, a new UCLA study implies. The team of astrophysicists and geochemists presents new evidence that the Earth is not unique. The study was published in the journal Science on Oct. 18.

“We have just raised the probability that many rocky planets are like the Earth, and there’s a very large number of rocky planets in the universe,” said co-author Edward Young, UCLA professor of geochemistry and cosmochemistry.

The scientists, led by Alexandra Doyle, a UCLA graduate student of geochemistry and astrochemistry, developed a new method to analyze in detail the geochemistry of planets outside of our solar system. Doyle did so by analyzing the elements in rocks from asteroids or rocky planet fragments that orbited six white dwarf stars.

“We’re studying geochemistry in rocks from other stars, which is almost unheard of,” Young said.

“Learning the composition of planets outside our solar system is very difficult,” said co-author Hilke Schlichting, UCLA associate professor of astrophysics and planetary science. “We used the only method possible — a method we pioneered — to determine the geochemistry of rocks outside of the solar system.”

White dwarf stars are dense, burned-out remnants of normal stars. Their strong gravitational pull causes heavy elements like carbon, oxygen and nitrogen to sink rapidly into their interiors, where the heavy elements cannot be detected by telescopes. The closest white dwarf star Doyle studied is about 200 light-years from Earth and the farthest is 665 light-years away.

“By observing these white dwarfs and the elements present in their atmosphere, we are observing the elements that are in the body that orbited the white dwarf,” Doyle said. The white dwarf’s large gravitational pull shreds the asteroid or planet fragment that is orbiting it, and the material falls onto the white dwarf, she said. “Observing a white dwarf is like doing an autopsy on the contents of what it has gobbled in its solar system.”

The data Doyle analyzed were collected by telescopes, mostly from the W.M. Keck Observatory in Hawaii, that space scientists had previously collected for other scientific purposes.

Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

“If I were to just look at a white dwarf star, I would expect to see hydrogen and helium,” Doyle said. “But in these data, I also see other materials, such as silicon, magnesium, carbon and oxygen — material that accreted onto the white dwarfs from bodies that were orbiting them.”

When iron is oxidized, it shares its electrons with oxygen, forming a chemical bond between them, Young said. “This is called oxidation, and you can see it when metal turns into rust,” he said. “Oxygen steals electrons from iron, producing iron oxide rather than iron metal. We measured the amount of iron that got oxidized in these rocks that hit the white dwarf. We studied how much the metal rusts.”

Rocks from the Earth, Mars and elsewhere in our solar system are similar in their chemical composition and contain a surprisingly high level of oxidized iron, Young said. “We measured the amount of iron that got oxidized in these rocks that hit the white dwarf,” he said.

The sun is made mostly of hydrogen, which does the opposite of oxidizing — hydrogen adds electrons.

The researchers said the oxidation of a rocky planet has a significant effect on its atmosphere, its core and the kind of rocks it makes on its surface. “All the chemistry that happens on the surface of the Earth can ultimately be traced back to the oxidation state of the planet,” Young said. “The fact that we have oceans and all the ingredients necessary for life can be traced back to the planet being oxidized as it is. The rocks control the chemistry.”

Until now, scientists have not known in any detail whether the chemistry of rocky exoplanets is similar to or very different from that of the Earth.

How similar are the rocks the UCLA team analyzed to rocks from the Earth and Mars?

“Very similar,” Doyle said. “They are Earth-like and Mars-like in terms of their oxidized iron. We’re finding that rocks are rocks everywhere, with very similar geophysics and geochemistry.”

“It’s always been a mystery why the rocks in our solar system are so oxidized,” Young said. “It’s not what you expect. A question was whether this would also be true around other stars. Our study says yes. That bodes really well for looking for Earth-like planets in the universe.”

White dwarf stars are a rare environment for scientists to analyze.

The researchers studied the six most common elements in rock: iron, oxygen, silicon, magnesium, calcium and aluminum. They used mathematical calculations and formulas because scientists are unable to study actual rocks from white dwarfs. “We can determine the geochemistry of these rocks mathematically and compare these calculations with rocks that we do have from Earth and Mars,” said Doyle, whose background is in geology and mathematics. “Understanding the rocks is crucial because they reveal the geochemistry and geophysics of the planet.”

“If extraterrestrial rocks have a similar quantity of oxidation as the Earth has, then you can conclude the planet has similar plate tectonics and similar potential for magnetic fields as the Earth, which are widely believed to be key ingredients for life,” Schlichting said. “This study is a leap forward in being able to make these inferences for bodies outside our own solar system and indicates it’s very likely there are truly Earth analogs.”

Young said his department has both astrophysicists and geochemists working together.

“The result,” he said, “is we are doing real geochemistry on rocks from outside our solar system. Most astrophysicists wouldn’t think to do this, and most geochemists wouldn’t think to ever apply this to a white dwarf.”

Co-authors are Benjamin Zuckerman, a UCLA professor of physics and astronomy, and Beth Klein, a UCLA astronomy researcher.

The research was funded by NASA.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

UC LA Campus

For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

#ancient-stars-shed-light-on-earths-similarities-to-other-planets, #astronomy, #astrophysics, #basic-research, #cosmology, #ucla

From UCLA Newsroom: “What moons in other solar systems reveal about planets like Neptune and Jupiter”


From UCLA Newsroom

October 10, 2019
Bradley Hansen

An exomoon hundreds of times the size of Earth might help astronomers find planets where life may thrive.

1
Exomoons may reveal secrets about how gas giants like Jupiter formed and what is in their core. NASA JPL-Caltech

What is the difference between a planet-satellite system as we have with the Earth and Moon, versus a binary planet — two planets orbiting each other in a cosmic do-si-do?

I am an astronomer interested in planets orbiting nearby stars, and gas giants — Jupiter, Saturn, Uranus and Neptune in our solar system — are the largest and easiest planets to detect. The crushing pressure within their gassy atmosphere means they are unlikely to be hospitable to life. But the rocky moons orbiting such planets could have conditions that are more welcoming. Last year, astronomers discovered a planet-sized exomoon orbiting another gas giant planet outside our solar system.

In a new paper [Science Advances], I argue that this exomoon is really what is called a captured planet.

Is the first detected ‘exomoon’ really a moon?

True Earth analogues, that orbit Sun-like stars, are very hard to detect, even with the large Keck telescopes.

Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

The task is easier if the host star is less massive. But then the planet has to be closer to the star to be warm enough, and the star’s gravitational tides may trap the planet in a state with a permanent hot side and a permanent cold side. This makes such planets less attractive as a potential location that could harbor life. When gas giants orbiting Sun-like stars have rocky moons, these may be more likely places to find life.

In 2018, two astronomers from Columbia University reported the first tentative observation of an exomoon [Science Advances] — a satellite orbiting a planet that itself orbits another star. One curious feature was that this exomoon Kepler-1625b-i was much more massive than any moon found in our solar system.

2
This artist’s impression depicts the exomoon candidate Kepler-1625b-i, the planet it is orbiting and the star in the centre of the star system. Kepler-1625b-i is the first exomoon candidate and, if confirmed, the first moon to be found outside the Solar System. Like many exoplanets, Kepler-1625b-i was discovered using the transit method. Exomoons are difficult to find because they are smaller than their companion planets, so their transit signal is weak, and their position in the system changes with each transit because of their orbit. This requires extensive modelling and data analysis. NASA/ESA

It has a mass similar to Neptune and orbits a planet similar in size to Jupiter.

Astronomers expect moons of planets like Jupiter and Saturn to have masses only a few percent of Earth. But this new exomoon was almost a thousand times larger than the corresponding bodies of our solar system — moons like Ganymede and Titan which orbit Jupiter and Saturn, respectively. It is very difficult to explain the formation of such a large satellite using current models of moon formation.

In a new model I developed, I discuss how such a massive exomoon forms through a different process, wherein it is really a captured planet.

All planets, large and small, start by gathering together asteroid-sized bodies to make a rocky core. At this early stage in the evolution of a planetary system, the rocky cores are still surrounded by a gaseous disk left over from the formation of the parent star. If a core can grow fast enough to reach a mass equivalent to 10 Earths, then it will have the gravitational strength to pull gas in from the surrounding space and grow to the massive size of Jupiter and Saturn. However, this gaseous accumulation is short-lived, as the star is draining away most of the gas in the disk, the dust and gas surrounding a newly formed star.

If there are two cores growing in close proximity, then they compete to capture rock and gas. If one core gets slightly larger, it gains an advantage and can capture the bulk of the gas in the neighborhood for itself. This leaves the second body without any further gas to capture. The increased gravitational pull of its neighbor drags the smaller body into the role of a satellite, albeit a very large one. The former planet is left as a super-sized moon, orbiting the planet that beat it out in the race to capture gas.

A remnant core as a look back into history

Viewed in this context, the captured planet is unlikely to be habitable. Growing planetary cores have gaseous envelopes, which make them more like Uranus and Neptune — a mix of rocks, ice and gas that would have become a Jupiter if it had not been so rudely cut off by its larger neighbor.

However, there are other implications that are almost as interesting. Studying the cores of giant planets is very difficult, because they are buried under several hundred Earth masses of hydrogen and helium. Currently, the JUNO mission is attempting to do this for Jupiter. However, studying the properties of this exomoon may enable astronomers to see the naked core of a giant gaseous planet when it is stripped of its gaseous envelope. This can provide a snapshot of what Jupiter may have looked like before it grew to its current enormous size.

This exomoon system Kepler-1625b-i is right at the edge of what is detectable with current technology. There may be many more objects like this that could be uncovered with future improvements in telescope capabilities. As astronomers’ census of exoplanets continues to grow, systems like the exomoon and its host highlight an issue that will become more important as we go forward. This exomoon reveals that the properties of a planet are not solely a consequence of its mass and position, but can depend on its history and the environment in which it formed.

See the full article here .


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Please help promote STEM in your local schools.

Stem Education Coalition

UC LA Campus

For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

#astronomy, #astrophysics, #basic-research, #cosmology, #last-year-astronomers-discovered-a-planet-sized-exomoon-orbiting-another-gas-giant-planet-outside-our-solar-system-i-argue-that-this-exomoon-is-really-what-is-called-a-captured-planet, #the-promise-of-exomoons, #ucla

From UCLA Newsroom: “Black hole at the center of our galaxy appears to be getting hungrier”


From UCLA Newsroom

September 11, 2019
Stuart Wolpert
UCLA
310-206-0511
swolpert@stratcomm.ucla.edu

UCLA astronomers notice brightest light in 24 years of observations.

1
Rendering of a star called S0-2 [Andrea Ghez’, UCLA Galactic Center Group, pet star] orbiting the supermassive black hole at the center of the Milky Way. It did not fall in, but its close approach could be one reason for the black hole’s growing appetite. Nicolle Fuller/National Science Foundation.

Star S0-2 Andrea Ghez Keck/UCLA Galactic Center Group at SGR A*, the supermassive black hole at the center of the milky way

The enormous black hole at the center of our galaxy is having an unusually large meal of interstellar gas and dust, and researchers don’t yet understand why.

“We have never seen anything like this in the 24 years we have studied the supermassive black hole,” said Andrea Ghez, UCLA professor of physics and astronomy and a co-senior author of the research. “It’s usually a pretty quiet, wimpy black hole on a diet. We don’t know what is driving this big feast.”

A paper about the study, led by the UCLA Galactic Center Group, which Ghez heads, is published today in Astrophysical Journal Letters.

The researchers analyzed more than 13,000 observations of the black hole from 133 nights since 2003. The images were gathered by the W.M. Keck Observatory in Hawaii and the European Southern Observatory’s Very Large Telescope in Chile.

Keck Observatory, operated by Caltech and the University of California, Maunakea Hawaii USA, 4,207 m (13,802 ft)

ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
•KUEYEN (UT2; The Moon ),
•MELIPAL (UT3; The Southern Cross ), and
•YEPUN (UT4; Venus – as evening star).
elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

The team found that on May 13, the area just outside the black hole’s “point of no return” (so called because once matter enters, it can never escape) was twice as bright as the next-brightest observation.

They also observed large changes on two other nights this year; all three of those changes were “unprecedented,” Ghez said.

The brightness the scientists observed is caused by radiation from gas and dust falling into the black hole; the findings prompted them to ask whether this was an extraordinary singular event or a precursor to significantly increased activity.

“The big question is whether the black hole is entering a new phase — for example if the spigot has been turned up and the rate of gas falling down the black hole ‘drain’ has increased for an extended period — or whether we have just seen the fireworks from a few unusual blobs of gas falling in,” said Mark Morris, UCLA professor of physics and astronomy and the paper’s co-senior author.

The team has continued to observe the area and will try to settle that question based on what they see from new images.

“We want to know how black holes grow and affect the evolution of galaxies and the universe,” said Ghez, UCLA’s Lauren B. Leichtman and Arthur E. Levine Professor of Astrophysics. “We want to know why the supermassive hole gets brighter and how it gets brighter.”

The new findings are based on observations of the black hole — which is called Sagittarius A*, or Sgr A* — during four nights in April and May at the Keck Observatory. The brightness surrounding the black hole always varies somewhat, but the scientists were stunned by the extreme variations in brightness during that timeframe, including their observations on May 13.

“The first image I saw that night, the black hole was so bright I initially mistook it for the star S0-2, because I had never seen Sagittarius A* that bright,” said UCLA research scientist Tuan Do, the study’s lead author. “But it quickly became clear the source had to be the black hole, which was really exciting.”

One hypothesis about the increased activity is that when a star called S0-2 made its closest approach to the black hole during the summer 2018, it launched a large quantity of gas that reached the black hole this year.

Another possibility involves a bizarre object known as G2, which is most likely a pair of binary stars, which made its closest approach to the black hole in 2014. It’s possible the black hole could have stripped off the outer layer of G2, Ghez said, which could help explain the increased brightness just outside the black hole.

Morris said another possibility is that the brightening corresponds to the demise of large asteroids that have been drawn in to the black hole.

No danger to Earth

The black hole is some 26,000 light-years away and poses no danger to our planet. Do said the radiation would have to be 10 billion times as bright as what the astronomers detected to affect life on Earth.

Astrophysical Journal Letters also published a second article by the researchers, describing speckle holography, the technique that enabled them to extract and use very faint information from 24 years of data they recorded from near the black hole.

Ghez’s research team reported July 25 in the journal Science the most comprehensive test of Einstein’s iconic general theory of relativity near the black hole. Their conclusion that Einstein’s theory passed the test and is correct, at least for now, was based on their study of S0-2 as it made a complete orbit around the black hole.

Ghez’s team studies more than 3,000 stars that orbit the supermassive black hole. Since 2004, the scientists have used a powerful technology that Ghez helped pioneer, called adaptive optics, which corrects the distorting effects of the Earth’s atmosphere in real time.

Keck Adaptive Optics

But speckle holography enabled the researchers to improve the data from the decade before adaptive optics came into play. Reanalyzing data from those years helped the team conclude that they had not seen that level of brightness near the black hole in 24 years.

“It was like doing LASIK surgery on our early images,” Ghez said. “We collected the data to answer one question and serendipitously unveiled other exciting scientific discoveries that we didn’t anticipate.”

Co-authors include Gunther Witzel, a former UCLA research scientist currently at Germany’s Max Planck Institute for Radio Astronomy; Mark Morris, UCLA professor of physics and astronomy; Eric Becklin, UCLA professor emeritus of physics and astronomy; Rainer Schoedel, a researcher at Spain’s Instituto de Astrofısica de Andalucıa; and UCLA graduate students Zhuo Chen and Abhimat Gautam.

The research is funded by the National Science Foundation, W.M. Keck Foundation, the Gordon and Betty Moore Foundation, the Heising-Simons Foundation, Lauren Leichtman and Arthur Levine, and Howard and Astrid Preston.

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

UC LA Campus

For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

#a-star-called-s0-2-andrea-ghez-ucla-galactic-center-group-pet-star, #andrea-ghez-keck-observatory-ucla-galactic-center-group, #astronomy, #astrophysics, #basic-research, #cosmology, #ucla

From UCLA Newsroom: “Technique could make better membranes for next-generation filtration”


From UCLA Newsroom

August 20, 2019
Writer
Wayne Lewis

Media Contact
Nikki Lin
310-206-8278
nlin@cnsi.ucla.edu

UCLA scientists’ method will allow more advanced materials to be used for desalination and other processes.

1
UCLA postdoctoral scholar Brian McVerry and doctoral student Mackenzie Anderson examine an ultra-thin membrane film on a glass plate used in the T-FLO process. Marc Roseboro/UCLA

Deriving drinkable water from seawater, treating wastewater and conducting kidney dialysis are just a few important processes that use a technology called membrane filtration.

The key to the process is the membrane filter — a thin, semi-porous film that allows certain substances such as water to pass through while separating out other, unwanted substances. But in the past 30 years, there have been no significant improvements in the materials that make up the key layers of commercially produced membrane filters.

Now, UCLA researchers have developed a new technique called thin-film liftoff, or T-FLO, for creating membrane filters. The approach could offer a way for manufacturers to produce more effective and energy-efficient membranes using high-performance plastics, metal-organic frameworks and carbon materials. To date, limitations in how filters are fabricated have prevented those materials from being viable in industrial production.

A study describing the work is published in the journal Nano Letters.

“There are a lot of materials out there that in the lab can do nice separations, but they’re not scalable,” said Richard Kaner, UCLA’s Dr. Myung Ki Hong Professor of Materials Innovation and the study’s senior author. “With this technique, we can take these materials, make thin films that are scalable, and make them useful.”

In addition to their potential for improving types of filtration that are performed using current technology, membranes produced using T-FLO could make possible an array of new forms of filtration, said Kaner, who also is a distinguished professor of chemistry and biochemistry, and of materials science and engineering, and a member of the California NanoSystems Institute at UCLA. For example, the technique might one day make it feasible to pull carbon dioxide out of industrial emissions — which would enable the carbon to be converted to fuel or other applications while also reducing pollution.

Filters like the ones used for desalination are called asymmetric membranes because of their two layers: a thin but dense “active” layer that rejects particles larger than a specific size, and a porous “support” layer that gives the membrane structure and allows it to resist the high pressures used in reverse osmosis and other filtering processes. The first asymmetric membrane for desalination was devised by UCLA engineers in the 1960s.

Today’s asymmetric membranes are made by casting the active layer onto the support layer, or casting both concurrently. But to manufacture an active layer using more advanced materials, engineers have to use solvents or high heat — both of which damage the support layer or prevent the active layer from adhering.

In the T-FLO technique, the active layer is cast as a liquid on a sheet of glass or metal and cured to make the active layer solid. Next, a support layer made of epoxy reinforced with fabric is added and the membrane is heated to solidify the epoxy.

The use of epoxy in the support layer is the innovation that distinguishes the T-FLO technique — it enables the active layer to be created first so that it can be treated with chemicals or high heat without damaging the support layer.

The membrane then is submerged in water to wash out the chemicals that induce pores in the epoxy and to loosen the membrane from the glass or metal sheet.

Finally, the membrane is peeled off of the plate with a blade — the “liftoff” that gives the method its name.

“Researchers around the world have demonstrated many new exciting materials that can separate salts, gases and organic materials more effectively than is done industrially,” said Brian McVerry, a UCLA postdoctoral scholar who invented the T-FLO process and is the study’s co-first author. “However, these materials are often made in relatively thick films that perform the separations too slowly or in small samples that are difficult to scale industrially.

“We have demonstrated a platform that we believe will enable researchers to use their new materials in a large, thin, asymmetric membrane configuration, testable in real-world applications.”

The researchers tested a membrane produced using T-FLO for removing salt from water, and it showed promise for solving one of the common problems in desalination, which is that microbes and other organic material can clog the membranes. Although adding chlorine to the water can kill the microbes, the chemical also causes most membranes to break down. In the study, the T-FLO membrane both rejected the salt and resisted the chlorine.

In other experiments, the new membrane was also able to remove organic materials from solvent waste and to separate greenhouse gases.

Mackenzie Anderson, a UCLA doctoral student, is co-first author of the study.

The research was supported by the U.S./China Clean Energy Research Center for Water-Energy Technologies and the National Science Foundation. The project is aligned with UCLA’s Sustainable LA Grand Challenge.

See the full article here .


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Please help promote STEM in your local schools.

Stem Education Coalition

UC LA Campus

For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

#technique-could-make-better-membranes-for-next-generation-filtration, #applied-research-technology, #we-have-demonstrated-a-platform-that-we-believe-will-enable-researchers-to-use-their-new-materials-in-a-large-thin-asymmetric-membrane-configuration-testable-in-real-world-applications, #in-the-t-flo-technique-the-active-layer-is-cast-as-a-liquid-on-a-sheet-of-glass-or-metal-and-cured-to-make-the-active-layer-solid, #material-sciences-2, #more-advanced-materials-to-be-used-for-desalination-and-other-processes, #t-flo, #the-new-membrane-was-also-able-to-remove-organic-materials-from-solvent-waste-and-to-separate-greenhouse-gases, #ucla

From UCLA Newsroom: “UCLA researchers toughen glass using nanoparticles”


From UCLA Newsroom

July 16, 2019
Matthew Chin

Process could be useful for applications in manufacturing and architecture.

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An electron microscope image of a new, tougher glass developed at UCLA, showing how nanoparticles (rounded, irregular shapes) deflect a crack and force it to branch out. SciFacturing Lab/UCLA

UCLA mechanical engineers and materials scientists have developed a process that uses nanoparticles to strengthen the atomic structure of glass. The result is a product that’s at least five times tougher than any glass currently available.

The process could yield glass that’s useful for industrial applications — in engine components and tools that can withstand high temperatures, for instance — as well as for doors, tables and other architectural and design elements.

The study was published online in the journal Advanced Materials and will be included in a future print edition. The authors wrote that same approach could also be used for manufacturing tougher ceramics that could be used, for example, in spacecraft components that are better able to withstand extreme heat.

In materials science, “toughness” measures how much energy a material can absorb — and how much it can deform — without fracturing. While glass and ceramics can be reinforced using external treatments, like chemical coatings, those approaches don’t change the fact that the materials themselves are brittle.

To solve that issue, the UCLA researchers took a cue from the atomic structure of metals, which can take a pounding and not break.

“The chemical bonds that hold glass and ceramics together are pretty rigid, while the bonds in metals allow some flexibility,” said Xiaochun Li, the Raytheon Professor of Manufacturing at the UCLA Samueli School of Engineering, and the study’s principal investigator. “In glass and ceramics, when the impact is strong enough, a fracture will propagate quickly through the material in a mostly straight path.

“When something impacts a metal, its more deformable chemical bonds act as shock absorbers and its atoms move around while still holding the structure together.”

The researchers hypothesized that by infusing glass with nanoparticles of silicon carbide, a metal-like ceramic, the resulting material would be able to absorb more energy before it would fail. They added the nanoparticles into molten glass at 3,000 degrees Fahrenheit, which helped ensure that the nanoparticles were evenly dispersed.

Once the material solidified, the embedded nanoparticles could act as roadblocks to potential fractures. When a fracture does occur, the tiny particles force it to branch out into tiny networks, instead of allowing it to take a straight path. That branching out enables the glass to absorb significantly more energy from a fracture before it causes significant damage.

Sintering, in which a powder is heated under pressure, and then cooled, is the main method used to make glass. It also was the method used in previous experiments by other research groups to disperse nanoparticles in glass or ceramics. But in those experiments, the nanoparticles weren’t spread evenly, and the resulting material had uneven toughness.

The glass blocks that the UCLA team developed for the experiment were somewhat milky, rather than clear, but Li said the process could be adapted to create clear glass.

The other authors of the study are Qiang-Guo Jiang, a visiting scholar in Li’s SciFacturing Laboratory; Chezheng Cao and Ting-Chiang Lin, who received their doctorates from UCLA in 2018; and Shanghua Wu, an engineering professor at Guangdong University of Technology, China.

See the full article here .


five-ways-keep-your-child-safe-school-shootings
Please help promote STEM in your local schools.

Stem Education Coalition

UC LA Campus

For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

#applied-research-technology, #chemistry, #glass-technology, #material-sciences-2, #nanotechnology, #ucla