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  • richardmitnick 8:10 pm on July 25, 2021 Permalink | Reply
    Tags: "All-in-one tool streamlines molecular weight analysis", , , Currently you need two orthogonal techniques: mass spectrometry and NMR spectroscopy to work out the molecular structure of a compound., , Organic chemistry, The science team has now developed an “all in one” NMR method that can predict the molecular weight of the compound.   

    From Griffith University (AU): “All-in-one tool streamlines molecular weight analysis” 

    Griffith U bloc

    From Griffith University (AU)

    July 20, 2021
    Carley Rosengreen

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    New world-first Griffith University-led research has streamlined the process of identifying the structure and molecular weight of compounds, which could have positive implications for scientists working in the fields of drug discovery, pollution analysis, food security and more.

    Published in Royal Society of Chemistry’s flagship journal Chemical Science, the team developed a novel Nuclear Magnetic Resonance-based (NMR) method to assign the molecular weight of compounds in mixtures which is a key asset for fields where individual components in complex mixtures need to be characterised.

    The research, led by Professor Anthony Carroll from Griffith’s School of Environment and Science and Griffith Institute for Drug Discovery with PhD graduate Guy Kleks and PhD candidates Darren Holland and Joshua Porter, is a breakthrough for scientists working on organic molecules.

    “Currently you need two orthogonal techniques: mass spectrometry and NMR spectroscopy to work out the molecular structure of a compound,” Professor Carroll said.

    “We’ve now condensed that into only needing one technique to work out the structure of the molecule.”

    The use of NMR, a similar method used in MRIs to image body parts, allows scientists to look at the unique “fingerprint of a compound”. It is the leading method used to identify the molecular structure of an unknown molecule.

    “But if you don’t know the compounds molecular weight, then using NMR techniques gets you a certain distance towards identifying what the structure of a molecule is but doesn’t get you all the way. Up until now this molecular weight was determined using mass spectrometry,” Professor Carroll said.

    Professor Carroll and his team have now developed an NMR method that can predict the molecular weight of the compound. This “all in one” method now means that the molecular structure can be confirmed more quickly so that the compound can be used for further developments.

    “What we’ve developed is actually a quick diagnostic tool that can help a whole range of areas including health and the environment,” Professor Carroll said.

    “Previously, it was like trying to find a needle in a haystack where one molecule out of a complex mixture was responsible for the effect that we see in, for example, cancer cells. That process generally requires us to do a whole lot of separation of molecules, which means a lot of time involved in doing purification and identification.

    “Every molecule has its own molecular weight. If you don’t know what that is, then then it’s difficult to know what that compound is.

    “What we’ve developed is a technique where we can look directly at this complex mixture and identify the individual molecules within it.”

    Professor Carroll hoped this world-first diagnostic method could become the adopted approach in the analysis of complex mixtures.

    See the full article here .

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    Stem Education Coalition

    Griffith U Campus

    In 1971, Griffith University (AU) was created to be a new kind of university—one that offered new degrees in progressive fields such as Asian studies and environmental science. At the time, these study areas were revolutionary—today, they’re more important than ever.

    Since then, we’ve grown into a comprehensive, research-intensive university, ranking in the top 5% of universities worldwide. Our teaching and research spans five campuses in South East Queensland and all disciplines, while our network of more than 120,000 graduates extends around the world.

    Griffith continues the progressive traditions of its namesake, Sir Samuel Walker Griffith, who was twice the Premier of Queensland, the first Chief Justice of the High Court of Australia, and the principal author of the Australian Constitution.

    Research

    Griffith researchers work in 38 centres and institutes, investigating areas such as water science, climate change adaptation, criminology and crime prevention, sustainable tourism and health and chronic disease.

    The University’s major research institutes include:

    Advanced Design and Prototyping Technologies Institute (ADaPT)
    Australian Rivers Institute
    Cities Research Institute
    Environmental Futures Research Institute
    Griffith Asia Institute
    Griffith Criminology Institute
    Griffith Institute for Educational Research
    Griffith Institute for Tourism
    Institute for Glycomics
    Institute for Integrated and Intelligent Systems
    Menzies Health Institute Queensland (formerly the Griffith Health Institute)
    Griffith Institute for Drug Discovery (GRIDD)

    Additionally, Griffith hosts several externally supported centres and facilities, including:

    Australian Institute for Suicide Research and Prevention
    National Climate Change Adaptation Research Facility
    Smart Water Research Centre
    NHMRC Centre of Research Excellence in Nursing

    Research commercialisation

    Griffith offers research commercialisation and services for business, industry and government through Griffith Enterprise.

    Other centres

    As well as research centres and institutes, Griffith has a number of cultural and community focused organisations. These include the EcoCentre, which provides a space for environmental education activities, exhibitions, seminars and workshops; and the Centre for Interfaith & Cultural Dialogue (formerly the Multi-Faith Centre).

     
  • richardmitnick 8:31 am on June 9, 2021 Permalink | Reply
    Tags: "Organic Molecules Offer Clues About Dying Stars and Outskirts of the Milky Way", , , Atacama Large Millimeter Array (CL), , , , , GHZ: Galactic Habitable Zone, , Organic chemistry, , , The Milky Way's GHZ region which includes the solar system is considered to have favorable conditions for the formation of life.,   

    From University of Arizona (US) : Women in STEM-Lucy Ziurys; Lilia Koelemay “Organic Molecules Offer Clues About Dying Stars and Outskirts of the Milky Way” 

    From University of Arizona (US)

    6.9.21

    Media contact:
    Daniel Stolte
    Science Writer, University Communications
    stolte@arizona.edu
    520-626-4402

    Researcher contact(s)
    Lucy Ziurys
    Department of Chemistry and Biochemistry
    lziurys@email.arizona.edu
    520-621-6525

    Researchers from the University of Arizona have detected organic molecules in planetary nebulae and in the far reaches of the Milky Way.

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    UArizona Regents Professor Lucy Ziurys and her collaborators took advantage of the radio antennas at the Atacama Large Millimeter Array (CL), or ALMA, to detect the very faint emissions of organic molecules in various planetary nebulae, remnants of dying stars. ALMA sits atop a plateau in Chile’s Atacama Desert, 16,500 feet above sea level, where the atmosphere is undisturbed and allows for clear observing. C. Padilla, National Radio Astronomy Observatory (US)/Associated Universities Inc (US)/National Science Foundation (US).

    University of Arizona researchers have observed, in unprecedented detail and spatial resolution, organic molecules in planetary nebulae, or the aftermath of dying stars. Their work sheds new light on how stars form and die.

    Using the Atacama Large Millimeter Array, or ALMA, UArizona Regents Professor Lucy Ziurys and her collaborators observed radio emissions from hydrogen cyanide, formyl ion and carbon monoxide in five planetary nebulae: M2-48, M1-7, M3-28, K3-45 and K3-58.

    The researchers presented their findings during the virtual 238th Meeting of the American Astronomical Society (US) on Tuesday.

    Planetary nebulae are bright objects produced when stars of a certain type reach the end of their evolution. Most stars in the galaxy, including the sun, are expected to end their lives this way.

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    The Twin Jet Nebula, or PN M2-9, is a striking example of a bipolar planetary nebula. The molecule emissions observed by Ziurys and her team outlined the shapes of some planetary nebulae, which previously had only been observed in visible light. In some cases, molecular signatures revealed previously unseen features. SA/Hubble & NASA/Judy Schmidt.

    As a dying star sheds large amounts of mass into space and becomes a white dwarf, it usually emits strong ultraviolet radiation. That radiation was long thought to break up any molecules hurled into the interstellar medium from the dying star and reduce them to atoms. However, detections of organic molecules in planetary nebulae in recent years have shown that this is not the case.

    The new observations by Ziurys and her team further support the idea that planetary nebulae instead seed the interstellar medium with molecules that serve as the raw ingredients for the formation of new stars and planets. Planetary nebulae are thought to provide 90% of the material in the interstellar medium, with supernovae adding the remaining 10%.

    “It was thought that molecular clouds, which would give rise to new stellar systems, would have to start from scratch and form these molecules from atoms,” said Ziurys, a Regents Professor of Chemistry and Astronomy at UArizona. “But if the process starts with molecules instead, it could dramatically accelerate chemical evolution in nascent star systems.”

    The molecule emissions observed by Ziurys and her team outlined the shapes of the planetary nebulae, which previously had only been observed in visible light. In some cases, molecular signatures revealed previously unseen features. A high resolution of one arcsecond – equivalent to a dime viewed from 2.5 miles away – resulted in striking images of the nebulae, showing the complex geometries of the dense, ejected material with bars, lobes and arcs never clearly observed before.

    Ziurys and her team believe the shapeshifting behavior in the nebulae geometry may be driven by certain processes involved in nucleosynthesis, or the forging of new elements inside a star.

    “It tells us that in a dying star, which is spherical until its final phase, some very interesting dynamics occur once it goes through the planetary nebula stage, which changes that spherical shape,” Ziurys said. “These stars just lose their mass, and so there’s really no mechanism for them to all of a sudden become bipolar or even quadrupolar.”

    It’s possible that helium flashes, which originate in a hot, convective shell around the core of a dying star, could provide a source of explosive nuclear synthesis away from the star’s center, resulting in the complex shapes seen in some nebulae, Ziurys said.

    “This could probably distort the spherical shape because a helium flash can explode through the poles of a star, where it will be directed by magnetic fields, and that will have an effect on the shape of the nebula that will form around it,” she said.

    Many planetary nebulae are something of an enigma, Ziurys said.

    “It’s been a puzzle to astronomers as to how you go from a spherical geometry into these multipolar geometries,” she said. “The molecules we observed trace the polar geometries beautifully, and so we’re hoping that this is going to give us some insight into the shaping of planetary nebulae.”

    Organic Molecules Also Present in Outskirts of the Milky Way

    In a second presentation at the AAS meeting, Lilia Koelemay, a doctoral student in Ziurys’ research group, reported on the discovery of organic molecules in the outskirts of the Milky Way, more than twice as far from the galactic center than what is known as the Galactic Habitable Zone, or GHZ.

    The Milky Way’s GHZ region which includes the solar system is considered to have favorable conditions for the formation of life.

    It is thought to extend to only up to 10 kiloparsecs, or about 32,600 light-years, from the galactic center.

    Using the UArizona ARO 12-Meter Telescope on Kitt Peak near Tucson, Koelemay, Ziurys and their collaborators searched 20 molecular clouds in the Milky Way’s Cygnus arms for signature emission spectra of methanol – a basic organic molecule. At 20 degrees Kelvin (approximately minus 423 degrees Fahrenheit), these clouds are extremely cold and far from the galactic center, at a distance of 13 to 23.5 kiloparsecs. The team detected methanol in all 20 clouds.

    According to Koelemay, the detection of these organic molecules at the galactic edge may imply that organic chemistry is still prevalent at the outer reaches of the galaxy, and the GHZ may extend much further from the galactic center than the current established boundary.

    “Scientists have wondered about the extent of organic chemistry in our galaxy for a long time, and it was always thought that not too far beyond our sun, we’re not going to see a lot of organic molecules,” Koelemay said. “The widely held assumption was that in the outskirts of our galaxy, the chemistry necessary to form organics just doesn’t occur.”

    That belief was partly based on the supposed dearth of organic molecules in the outer reaches of the galaxy, Koelemay said. The notion of the galactic habitable zone is based on the idea that for conditions to exist where life can evolve, a planetary system can’t be too close to the galactic center with its extremely high density of stars and intense radiation. It also can’t be too far out, because there would not be enough elements critical for life, such as oxygen, carbon and nitrogen.

    Koelemay’s observations were made possible by a new 2-millimeter wavelength receiver with unprecedented sensitivity.

    3
    Detections of organic molecules in the outer reaches of the Milky Way were made possible by this new 2-millimeter wavelength receiver developed in a collaboration with Ziurys, Steward Observatory engineer Gene Lauria and the National Radio Astronomy Observatory. Steward Observatory/University of Arizona.

    Developed in a collaboration with Ziurys, Steward Observatory engineer Gene Lauria and the National Radio Astronomy Observatory, the receiver allows for detection of molecular emission lines in a wavelength bandwidth radio astronomers in the U.S. couldn’t access for years.

    “Without this new instrument, these observations would have taken hundreds of hours, which is not feasible,” Ziurys said. “With this new capability, we expect to dramatically open our observation window and detect molecules in other regions of our galaxy previously thought to be devoid of such chemistry.”

    Koelemay has begun looking for other molecules besides methanol – such as methyl cyanide, organic molecules with ring structures, and others that contain functional groups known to be crucial building blocks for biomolecules. Discoveries of those molecules in the interstellar medium have attracted much interest, as many researchers deem them promising candidates for the emergence of life. When organic molecules are present in emerging planetary systems, they can condense onto the surfaces of asteroids, which then deliver them to nascent planets, where they could potentially jumpstart the evolution of life.

    “We’re finding these species way on the outskirts of the galaxy, and the abundance doesn’t even drop off 10 kiloparsecs from the solar system, where the chemistry necessary for building the molecules necessary for life just wasn’t believed to occur,” said Ziurys, Koelemay’s adviser and a co-author of the research. “The fact that they’re there expands the prospects of habitable planets forming far beyond what has been considered the habitable zone, and it is extremely exciting.”

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    As of 2019, the University of Arizona (US) enrolled 45,918 students in 19 separate colleges/schools, including the UArizona College of Medicine in Tucson and Phoenix and the James E. Rogers College of Law, and is affiliated with two academic medical centers (Banner – University Medical Center Tucson and Banner – University Medical Center Phoenix). UArizona is one of three universities governed by the Arizona Board of Regents. The university is part of the Association of American Universities and is the only member from Arizona, and also part of the Universities Research Association(US). The university is classified among “R1: Doctoral Universities – Very High Research Activity”.

    Known as the Arizona Wildcats (often shortened to “Cats”), the UArizona’s intercollegiate athletic teams are members of the Pac-12 Conference of the NCAA. UArizona athletes have won national titles in several sports, most notably men’s basketball, baseball, and softball. The official colors of the university and its athletic teams are cardinal red and navy blue.

    After the passage of the Morrill Land-Grant Act of 1862, the push for a university in Arizona grew. The Arizona Territory’s “Thieving Thirteenth” Legislature approved the UArizona in 1885 and selected the city of Tucson to receive the appropriation to build the university. Tucson hoped to receive the appropriation for the territory’s mental hospital, which carried a $100,000 allocation instead of the $25,000 allotted to the territory’s only university (Arizona State University(US) was also chartered in 1885, but it was created as Arizona’s normal school, and not a university). Flooding on the Salt River delayed Tucson’s legislators, and by they time they reached Prescott, back-room deals allocating the most desirable territorial institutions had been made. Tucson was largely disappointed with receiving what was viewed as an inferior prize.

    With no parties willing to provide land for the new institution, the citizens of Tucson prepared to return the money to the Territorial Legislature until two gamblers and a saloon keeper decided to donate the land to build the school. Construction of Old Main, the first building on campus, began on October 27, 1887, and classes met for the first time in 1891 with 32 students in Old Main, which is still in use today. Because there were no high schools in Arizona Territory, the university maintained separate preparatory classes for the first 23 years of operation.

    Research

    UArizona is classified among “R1: Doctoral Universities – Very high research activity”. UArizona is the fourth most awarded public university by National Aeronautics and Space Administration(US) for research. UArizona was awarded over $325 million for its Lunar and Planetary Laboratory (LPL) to lead NASA’s 2007–08 mission to Mars to explore the Martian Arctic, and $800 million for its OSIRIS-REx mission, the first in U.S. history to sample an asteroid.

    The LPL’s work in the Cassini spacecraft orbit around Saturn is larger than any other university globally. The UArizona laboratory designed and operated the atmospheric radiation investigations and imaging on the probe. UArizona operates the HiRISE camera, a part of the Mars Reconnaissance Orbiter. While using the HiRISE camera in 2011, UArizona alumnus Lujendra Ojha and his team discovered proof of liquid water on the surface of Mars—a discovery confirmed by NASA in 2015. UArizona receives more NASA grants annually than the next nine top NASA/JPL-Caltech(US)-funded universities combined. As of March 2016, the UArizona’s Lunar and Planetary Laboratory is actively involved in ten spacecraft missions: Cassini VIMS; Grail; the HiRISE camera orbiting Mars; the Juno mission orbiting Jupiter; Lunar Reconnaissance Orbiter (LRO); Maven, which will explore Mars’ upper atmosphere and interactions with the sun; Solar Probe Plus, a historic mission into the Sun’s atmosphere for the first time; Rosetta’s VIRTIS; WISE; and OSIRIS-REx, the first U.S. sample-return mission to a near-earth asteroid, which launched on September 8, 2016.

    UArizona students have been selected as Truman, Rhodes, Goldwater, and Fulbright Scholars. According to The Chronicle of Higher Education, UArizona is among the top 25 producers of Fulbright awards in the U.S.

    UArizona is a member of the Association of Universities for Research in Astronomy(US), a consortium of institutions pursuing research in astronomy. The association operates observatories and telescopes, notably Kitt Peak National Observatory(US) just outside Tucson. Led by Roger Angel, researchers in the Steward Observatory Mirror Lab at UArizona are working in concert to build the world’s most advanced telescope. Known as the Giant Magellan Telescope(CL), it will produce images 10 times sharper than those from the Earth-orbiting Hubble Telescope.

    Giant Magellan Telescope, 21 meters, to be at the NOIRLab(US) National Optical Astronomy Observatory(US) Carnegie Institution for Science’s(US) Las Campanas Observatory(CL), some 115 km (71 mi) north-northeast of La Serena, Chile, over 2,500 m (8,200 ft) high.


    The telescope is set to be completed in 2021. GMT will ultimately cost $1 billion. Researchers from at least nine institutions are working to secure the funding for the project. The telescope will include seven 18-ton mirrors capable of providing clear images of volcanoes and riverbeds on Mars and mountains on the moon at a rate 40 times faster than the world’s current large telescopes. The mirrors of the Giant Magellan Telescope will be built at UArizona and transported to a permanent mountaintop site in the Chilean Andes where the telescope will be constructed.

    Reaching Mars in March 2006, the Mars Reconnaissance Orbiter contained the HiRISE camera, with Principal Investigator Alfred McEwen as the lead on the project. This National Aeronautics and Space Administration(US) mission to Mars carrying the UArizona-designed camera is capturing the highest-resolution images of the planet ever seen. The journey of the orbiter was 300 million miles. In August 2007, the UArizona, under the charge of Scientist Peter Smith, led the Phoenix Mars Mission, the first mission completely controlled by a university. Reaching the planet’s surface in May 2008, the mission’s purpose was to improve knowledge of the Martian Arctic. The Arizona Radio Observatory(US), a part of UArizona Department of Astronomy Steward Observatory(US), operates the Submillimeter Telescope on Mount Graham.

    The National Science Foundation(US) funded the iPlant Collaborative in 2008 with a $50 million grant. In 2013, iPlant Collaborative received a $50 million renewal grant. Rebranded in late 2015 as “CyVerse”, the collaborative cloud-based data management platform is moving beyond life sciences to provide cloud-computing access across all scientific disciplines.
    In June 2011, the university announced it would assume full ownership of the Biosphere 2 scientific research facility in Oracle, Arizona, north of Tucson, effective July 1. Biosphere 2 was constructed by private developers (funded mainly by Texas businessman and philanthropist Ed Bass) with its first closed system experiment commencing in 1991. The university had been the official management partner of the facility for research purposes since 2007.

    U Arizona mirror lab-Where else in the world can you find an astronomical observatory mirror lab under a football stadium?

    University of Arizona’s Biosphere 2, located in the Sonoran desert. An entire ecosystem under a glass dome? Visit our campus, just once, and you’ll quickly understand why the UA is a university unlike any other.

     
  • richardmitnick 10:04 am on March 5, 2021 Permalink | Reply
    Tags: "For The First Time Organic Matter Crucial For Life Has Been Found on an Asteroid's Surface", , , , , , , Most of Earth's meteorites come from S-type asteroids like Itokawa., Organic chemistry, , The asteroid Itokawa   

    From Science Alert(AU): “For The First Time Organic Matter Crucial For Life Has Been Found on an Asteroid’s Surface” 

    ScienceAlert

    From Science Alert(AU)

    5 MARCH 2021
    MIKE MCRAE

    1
    A grain of dust (circled) from Itokawa (ISAS-Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構; Kokuritsu-kenkyū-kaihatsu-hōjin Uchū Kōkū Kenkyū Kaihatsu Kikō](JP)

    Follow the twisted limbs of your family tree all the way back to its primordial origins billions of years in the past and you’ll find that we all originated from dust rich in organic chemistry.

    Just where this organic dust came from has been a topic of debate for more than half a century. Now, researchers have found the first evidence of organic materials essential to life on Earth on the surface of an S-type asteroid.

    An international team of researchers recently conducted an in-depth analysis on one of the particles brought back from the asteroid Itokawa by the Japan Aerospace Exploration Agency (JAXA) (国立研究開発法人宇宙航空研究開発機構; Kokuritsu-kenkyū-kaihatsu-hōjin Uchū Kōkū Kenkyū Kaihatsu Kikō](JP) original Hayabusa mission back in 2010.

    JAXA Hayabusa2

    Most of Earth’s meteorites come from S-type asteroids like Itokawa, so knowing that it could have contained essential ingredients for life on our planet is a significant step forward in our understanding of how life-forming conditions could arise. Up until now, most research on organic material has focussed on carbon-rich (c-class) asteroids.

    Looking into the sample, the team found that organic material that came from the asteroid itself has evolved over time through extreme conditions – incorporating water and organic matter from other sources.

    This is similar to the process that happened on Earth, and helps us better understand how the earliest forms of terrestrial biochemistry might simply be an extension of the chemistry taking place inside many asteroids.

    “These findings are really exciting as they reveal complex details of an asteroid’s history and how its evolution pathway is so similar to that of the prebiotic Earth,” says earth scientist Queenie Chan from the Royal Holloway University(UK).

    Evolutionary models can take us back some 3.5 billion years to a time when life was little more than competing sequences of nucleic acid.

    Step back any further and we’re forced to consider how elements like hydrogen, oxygen, nitrogen, and carbon might join to form amazingly complex molecules capable of self-arranging into stuff that behaves like RNA, proteins, and fatty acids.

    In the 1950s, as researchers were first considering the prickly question of how simpler ingredients might spontaneously cook up an organic soup, experiments showed conditions on Earth’s surface might do a sufficient job.

    Nearly seven decades later, our focus has turned to the slow and steady chemical processes inside the very rocks that aggregated into worlds like ours.

    Evidence isn’t hard to come by. It’s now clear a steady rain of rock and ice billions of years ago could have delivered molecules of cyanide, the sugar ribose, and even amino acids – along with a generous donation of water – onto Earth’s surface.

    But the degree to which the chemistry of meteorites could have been contaminated by things on Earth leaves some room for doubt.

    Since Hayabusa’s return a decade ago, more than 900 particles of pristine asteroid dirt taken from its payload have been separated and stored in a JAXA clean room.

    Fewer than 10 have been studied for signs of organic chemistry, but all of them were found to contain molecules predominantly made up of carbon.

    Itokawa is what’s referred to as a stony (or siliceous) class of asteroid, or s-class. Following early studies on its material, it’s also believed to be an ordinary chondrite – a relatively unmodified type of space rock representing a more primitive state of the inner Solar System.

    Given these types of asteroids make up a good chunk of the minerals smashing into our planet, and aren’t generally thought to contain much in the way of organic chemistry, those early findings were intriguing, to say the least.

    Chan and her colleagues took just one of these grains of dust, a 30 micrometre wide particle shaped a little like the continent of South America, and conducted a detailed analysis of its make-up, including a study of its water contents.

    They found a rich variety of carbonaceous compounds, including signs of disordered polyaromatic molecules of a clearly extraterrestrial origin, and structures of graphite.

    “After being studied in great detail by an international team of researchers, our analysis of a single grain, nicknamed ‘Amazon’, has preserved both primitive (unheated) and processed (heated) organic matter within ten microns (a thousandth of a centimetre) of distance,” says Chan.

    “The organic matter that has been heated indicates that the asteroid had been heated to over 600°C in the past. The presence of unheated organic matter very close to it, means that the in-fall of primitive organics arrived on the surface of Itokawa after the asteroid had cooled down.”

    Itokawa has had an exciting history for a rock that has nothing better to do than float idly around the Sun for a few billion years, having been modified with a good baking, dehydrated, then rehydrated with a new coating of fresh material.

    While its story isn’t quite as exciting as our own planet’s history, the asteroid’s activity does describe the cooking of organic material in space as a complex process, and isn’t limited to carbon-rich asteroids.

    Late last year, Hayabusa2 returned with a sample of a c-class, near-Earth asteroid named Ryugu. Comparing the contents of its payload with those of its predecessor will no doubt contribute even more knowledge of how organic chemistry evolves in space.

    The question of life’s origins and its seeming uniqueness on Earth is one that we’ll be seeking answers to for a long time to come. But every new discovery is pointing to a story that stretches far beyond the safe, warm puddles our newborn planet.

    This research was published in Scientific Reports.

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

     
  • richardmitnick 11:31 am on February 9, 2021 Permalink | Reply
    Tags: "Pringles and the Role of Chance", , , It’s a simple research question but one that's tricky to answer: How do you go about finding completely new materials?, , Michel Rickhaus and Fabian von Rohr are both on the lookout for novel materials., Michel Rickhaus’s group in turn specializes in making “intelligent” wires that respond to their surroundings and heal themselves and which can even be put together and dismantled on command., Organic chemistry, , The researchers could find new results in fundamental components in so-called spintronics; valleytronics; and topotronics., They haven’t yet collaborated but each follows the other’s research with interest., , Von Rohr’s research group is working at high temperatures to fabricate “emergent” quantum materials and new materials with so-called non-trivial topological electronic states., While von Rohr gives chance a chance Rickhaus sees himself as more of an artist- a sculptor., You could imagine these new materials as undiscovered islands.   

    From University of Zürich (Universität Zürich) (CH): “Pringles and the Role of Chance” 

    From University of Zürich (Universität Zürich) (CH)

    1
    Taking different paths to the same destination? The two chemists Fabian von Rohr (left) and Michel Rickhaus experiment with new materials. Credit: Jos Schmid.

    Chemists Michel Rickhaus and Fabian von Rohr specialize in looking for new materials that could play an important role in the electronics of the future.

    It’s a simple research question, but one that’s tricky to answer: How do you go about finding completely new materials? For example superconductors, substances that can conduct electricity with no losses whatsoever. Or in earlier days, perhaps, glass, a solid material that’s completely transparent − a property that before the invention of glass 2,000 years ago might well have been attributed to magic. Michel Rickhaus and Fabian von Rohr are both on the lookout for novel materials of this sort. They don’t see themselves as magicians at all, but they do admit to enjoying a little bit tinkering. Each of them and their teams are taking an entirely different path in search of a substance that behaves quite differently than what you would expect from “normal” materials. Von Rohr’s research group is working at high temperatures to fabricate “emergent” quantum materials and new materials with so-called non-trivial topological electronic states. Behind these mysterious sounding names might lie the future of electronics. Michel Rickhaus’s group in turn specializes in making “intelligent” wires that respond to their surroundings and heal themselves, and which can even be put together and dismantled on command. It sure sounds a bit like magic.

    Extreme physical states

    Both researchers have received a substantial grant from the University of Zürich Research Talent Development Fund (FAN; see box) for their innovative approaches. They haven’t yet collaborated, but each follows the other’s research with interest. Rickhaus sees a certain amount of serendipity in von Rohr’s work. By that he means an openness to chance findings, a willingness to look left and right while you’re foraging. To an extent, von Rohr agrees with his colleague. In their lab, his group make materials under extreme physical states to force compounds of chemical elements into unfamiliar arrangements.

    While von Rohr gives chance a chance, Rickhaus sees himself as more of an artist, a sculptor. “We find out what sort of properties a chemical structure has by actually creating it.” A certain willingness to experiment can do no harm here either. As Rickhaus explains, you only find new materials if you look for them. “It might sound trivial, but finding them means manufacturing them – without always knowing exactly what will emerge in the process.” Having a good idea isn’t enough. “You then need to synthesize and characterize the substance in question.”

    Quantum mechanical magic tricks

    If you’re lucky, what comes out of this process can be groundbreaking and urgently required in fields of application such as electronics. It’s assumed that the silicon age will soon be over as conventional chips reach their physical limits. What follows is already emerging in research labs – the post-silicon age. Among other things, it will involve new types of quantum materials. The properties of these materials are dominated by macroscopic quantum effects “that arise on the basis of emergent collective interactions between electrons,” as von Rohr puts it. In other words, an entire material suddenly pulls off quantum mechanical magic tricks. Materials of this sort could potentially be used in completely novel electronic applications. They could serve as fundamental components in so-called spintronics, valleytronics and topotronics. These new forms of electronics not only use the charges of particles to process information, but also additional quantum mechanical properties, for example their topology. The topological nature of electronic states is a key concept that in recent years has led to a real revolution in the way quantum materials are understood. Von Rohr and his ambitious group of researchers are trying to find out exactly what properties materials must have to best facilitate these non-classical, “non-trivial” electronic states.

    “Our day-to-day research in the lab could hardly be more different,” says Fabian von Rohr of Michel Rickhaus’s work, even though there might be overlaps in terms of application. But where this application might lie is something that people doing fundamental research don’t yet know for sure. You could imagine these new materials as undiscovered islands: “From a distance, we sense that there’s an island out there on the horizon, but we first have to go there to explore it.” And for his research approach at least, von Rohr admits that “it could actually happen that we chance upon a whole continent.”

    Stacking molecules

    Michel Rickhaus has fewer expectations that his research will lead to the discovery of a new continent. With a background in organic chemistry, he’s used to building compounds from the ground up. Unlike those working in the currently dominant polymer chemistry, which involves working with huge, firmly chained molecules, his group endeavors to build materials on a gradual basis. Developing a design like this from scratch is hard work – making sure even only 20 atoms hang together precisely is a herculean task. Rickhaus had the brilliant idea of working with small molecular components and repeating these tiny units thousands or even billions of times, stacking them, lining them up and allowing them to grow into larger structures – such as wires. “In classic organic chemistry, the form of the molecule itself isn’t so important,” says Rickhaus. “But we have an architectural approach that works systematically with the shapes of molecules.” Seen from this perspective, a wire is nothing other than a miniature tower. The only thing is, “if you want to construct a tower you can simply layer flat disks one on top of the other. But a tower built this way will be wobbly, because it’s much too easy for the individual elements to shift in relation to one another.” If, instead of this, you use saddle-shaped molecules, you can create something like a stack of Pringles that’s much more stable. Rickhaus’s goal is for a small molecule which doesn’t have any interesting material properties of its own to become something bigger that at some point develops a property such as conductivity. And then for it to be used or incorporated as a material in a specific application. Their research is about moving from pure research into the real world.

    Purely rational approach doesn’t work

    This has a great side-effect. As these small building blocks aren’t covalently connected, it’s also fairly easy to manipulate the “building”, as it were. With the right chemical or physical prod, it collapses back into its individual molecules. Or you can change the ambient conditions to activate “self-healing” abilities, and the molecules rearrange themselves in line with their macro structure. Unlike von Rohr, who sometimes simply lets things happen and looks to see what comes out of it, Rickhaus tries to define as many parameters as possible in advance. “We code the spatial arrangement within the individual building blocks.” Of course, not everything can be planned here either. For example, it might be that “you want to let a straight stack grow and suddenly end up with a ring,” explains the chemist.

    Surprises like this can trigger new ideas. Rickhaus believes a materials scientist has to have a playful side, simply because a purely rational approach wouldn’t work. Von Rohr concurs; it’s very important to experiment with an open mind. At that point the question of an application is still a long way off. Maybe one in a hundred ideas will turn out to be viable. This perhaps shows most clearly what distinguishes a successful young researcher above all – persistence.

    See the full article here .

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    The University of Zürich (Universität Zürich) (CH), located in the city of Zürich, is the largest university in Switzerland, with over 26,000 students. It was founded in 1833 from the existing colleges of theology, law, medicine and a new faculty of philosophy.

    Currently, the university has seven faculties: Philosophy, Human Medicine, Economic Sciences, Law, Mathematics and Natural Sciences, Theology and Veterinary Medicine. The university offers the widest range of subjects and courses of any Swiss higher education institutions.

     
  • richardmitnick 2:15 pm on January 27, 2021 Permalink | Reply
    Tags: "Studies Provide Answers About Promising 2D Materials", , , , Doping - adding impurities such as boron or phosphorus to silicon for example - is essential to developing semiconductors., , In the first study Cha used molybdenum disulfide (MoS2)., Instead because 2D materials are pretty much all surface researchers can sprinkle small molecules known as organic electron donors (OED) onto the surfaces and activate the 2D materials., , , Organic chemistry, , Two-dimensional layered materials hold great promise for a number of applications.,   

    From Yale School of Engineering and Applied Science: “Studies Provide Answers About Promising 2D Materials” 

    Yale University

    From Yale School of Engineering and Applied Science

    01/26/2021

    Two-dimensional, layered materials hold great promise for a number of applications, such as alternative platforms for the next-generation of logic and memory devices and flexible energy storage devices. There’s still much, however, that remains unknown about them.

    1
    This visualisation shows layers of graphene used for membranes. Credit: University of Manchester.

    Two studies from the lab of Judy Cha, the Carol and Douglas Melamed Associate Professor of Mechanical Engineering & Materials Science and a member of Yale West Campus Energy Sciences Institute, answer some crucial questions about these materials. Both studies were funded with grants from the Army Research Office (ARO), an element of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory, and have been published in Advanced Electronic Materials.

    In one paper [Advanced Electronic Materials], Cha and her team of researchers, in collaboration with Yale chemistry professors Nilay Hazari and Hailiang Wang, experimentally measured the precise doping effects of small molecules on 2D materials – a first step toward tailoring molecules for modulating the electrical properties of 2D materials. In the process of doing so, they also achieved a very high doping concentration.

    Doping – adding impurities such as boron or phosphorus to silicon, for example – is essential to developing semiconductors. It allows for the tuning of the carrier densities – the number of electrons and other charge-carriers – to produce a functional device. Conventional doping methods, however, tend to be too energy-intensive and potentially damaging to work well for 2D materials.

    Instead, because 2D materials are pretty much all surface, researchers can sprinkle small molecules known as organic electron donors (OED) onto the surfaces, and activate the 2D materials – that is, create surface functionalization. Thanks to organic chemistry, the method is remarkably effective. It also greatly widens the choice for the material being used. For this study, Cha used molybdenum disulfide (MoS2).

    However, to further optimize these materials, researchers need a greater level of precision. They need to know how many electrons each molecule of the OED donates to the 2D material, and how many molecules are needed altogether.

    “By doing so, we can go forward and design properly, knowing how to tweak the molecules and then increase the carrier densities,” Cha said.

    To make this calibration, Cha and her team used atomic force microscopy at the Imaging Core at Yale’s West Campus. For their material, they achieved a doping efficiency of about one electron per molecule, which allowed them to demonstrate the highest doping level ever achieved in MoS2. This was possible only by the precise measurements that were conducted.

    “Now that we know the doping power, we are no longer in the dark space of not knowing where we are,” she said. “Before, we could dope but couldn’t know how effective that doping is. Now we have some target electron densities that we want to achieve and we feel like we know how to get there.”

    In a second paper [Advanced Electronic Materials], Cha’s team looked at the effects of mechanical strain on the ordering of lithium in lithium-ion batteries.

    Current commercial lithium ion batteries use graphite as the anode. When lithium is inserted into the gaps between graphene layers that make up graphite, the gaps need to expand to make room for the lithium atoms.

    “So we asked ‘What if you stopped this expansion?’” Cha said. “We found that local straining affects the ordering of the lithium ion. The lithium ions effectively get slowed down.”

    When there’s a strain energy, lithium is not able to move as freely as before, and more energy is required to force the lithium into its preferred configuration.

    By calculating the exact effects of the strain energy, Cha’s research team was able to precisely demonstrate how much the lithium atoms slow down.

    The study has broader implications, particularly if the field moves away from lithium batteries in favor of those made from other more readily available materials, such as sodium or magnesium, which can also be used for rechargeable batteries.

    “Sodium and magnesium are much larger, so the gap needs to expand much more compared to lithium, so the effects of strain will be much more dramatic,” she said. The experiments in the study provide a similar understanding of the effects that mechanical strain could have on these other materials.

    ARO researchers said Cha’s studies will be very helpful in advancing their own work.

    “The results obtained in these two studies related to novel two dimensional materials are of great importance to develop future advanced Army applications in sensing and energy storage,” said Dr. Pani Varanasi, branch chief, ARO.

    See the full article here .

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    Please help promote STEM in your local schools.

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    Yale School of Engineering and Applied Science Daniel L Malone Engineering Center.

    The Yale School of Engineering & Applied Science is the engineering school of Yale University. When the first professor of civil engineering was hired in 1852, a Yale School of Engineering was established within the Yale Scientific School, and in 1932 the engineering faculty organized as a separate, constituent school of the university. The school currently offers undergraduate and graduate classes and degrees in electrical engineering, chemical engineering, computer science, applied physics, environmental engineering, biomedical engineering, and mechanical engineering and materials science.

    Yale University comprises three major academic components: Yale College (the undergraduate program), the Graduate School of Arts and Sciences, and the professional schools. In addition, Yale encompasses a wide array of centers and programs, libraries, museums, and administrative support offices. Approximately 11,250 students attend Yale.

     
  • richardmitnick 11:43 am on July 21, 2020 Permalink | Reply
    Tags: "In his element in the chem lab and the kickboxing ring", , , , , Organic chemistry, PhD student Levi Knippel   

    From MIT News: “In his element in the chem lab and the kickboxing ring” PhD student Levi Knippel 

    MIT News

    From MIT News

    July 20, 2020
    Sofia Tong

    1
    “I feel like I need to pay forward all the opportunities and help that have been provided to me,” says PhD student Levi Knippel. Credit: Adam Glanzman.

    2
    Knippel describes kickboxing as a challenging puzzle that requires creativity and strategy more than brute strength. “It helped me break out of my shell,” he says of the sport. “This zen state of just me, my body, and him trying to hurt me –– it’s like this chess match.” Credit: Adrian Childress Photography.

    PhD student Levi Knippel is dedicated to making the Department of Chemistry “a community that everyone wants to be a part of.”

    Before coming to MIT to pursue a PhD in chemistry, Levi Knippel would spend hours after his workdays at Genentech, where he was an associate scientist, training with two world champion kickboxers. “It helped me break out of my shell,” he says of the sport. “This zen state of just me, my body, and my opponent trying to hurt me –– it’s like this chess match.”

    In the ring, he has a combined record of one win, one loss, and one draw. “Nice and balanced,” he says with a laugh.

    Knippel describes kickboxing as a challenging puzzle that requires creativity and strategy more than brute strength. A similar, though less physical, affinity for such puzzle-solving drew him to organic chemistry in high school, and ultimately to MIT, where he now studies copper-hydride chemistry. Working with molecules also requires a delicate sense of touch and balance, he says.

    Unfortunately, both passions have been put on hold for the moment, due to the Covid-19 pandemic and a torn shoulder that’s kept him out of the ring. Instead of managing reactions and purifying materials in the lab, he has been writing manuscripts, submitting abstracts to conferences, and studying for his oral exam, at his home in Allston, Massachusetts. “I miss working with my hands,” he says. “When you get that material you’ve been working on for a couple weeks, and you hold that powder in your hands, it’s really satisfying.”

    Wrestling with compounds

    As part of the Buchwald Research Group in the Department of Chemistry, Knippel works on taking olefins, chemicals that are relatively easy and cheap to produce, and using copper catalysts to generate new compounds that might someday aid in the design of new drugs and other therapies. These compounds are chiral, having two possible orientations; in many cases, only one of those orientations might be effective in the body.

    In the initial few months of his thesis project, it seemed like he was getting 95 percent of the desired chirality, but it would stubbornly turn into a 50-50 mixture over time. Ultimately, he solved this issue, which turned out to be related to his purification method. “You have to every day go to work and continue to have self-confidence to know that you’re doing everything right,” Knippel says. “Sometimes the chemistry just doesn’t work. If it worked, it would have already been discovered.”

    Knippel says the chemistry department community gets him through the really difficult moments, which has also motivated him to take on leadership roles within it. As the president of the Chemistry Graduate Student Committee, he’s been liaising with other groups like Women in Chemistry and the Chemistry Alliance for Diversity and Inclusion to make the department more welcoming and inclusive. One event he remembers fondly was a department fall festival last year which marked the first big collaboration between all the student groups. “It’s just a joint effort among all these groups to make it a community that everyone wants to be a part of,” he says.

    His department, he says, is the kind of place where, after learning that he had been through a particularly bad day, every member of his 40+ person cohort gave him a hug. “That’s when I knew I was in the right place,” he recalls.

    A long way from home

    Part of what set Knippel on the path to MIT was his strong mentorship during his undergraduate years at Johns Hopkins University. “Looking back now it was kind of presumptuous,” he says, recalling how he met his mentor, chemistry professor Thomas Lectka. On the very first day of his first year, Knippel boldly knocked on Lectka’s office door, entered, and got a position as a lab researcher. “I wanted to see how the sausage is made, so to speak,” he says. “I ended up loving it. I realized that if I do this as a career, no two days would be the same for the rest of my life.”

    But at Hopkins, undergraduate research was unpaid –– and Knippel, even on full scholarship, struggled to make ends meet. Lectka helped him land a teaching assistant position that allowed him to stop working campus jobs and instead to deepen his experience in the field while maintaining a consistent source of income.

    “What he did to make me be able to focus on science was huge,” Knippel says. “I just can’t imagine that I’d be where I am now if he hadn’t given me these opportunities to prove myself. I feel like I worked much harder because he was going out of his way to make my life easier.”

    Finding the TA position was just one of the ways that Knippel had to navigate college as a low-income student. It had come as a surprise to him, and to many that he grew up with, that top universities had robust financial aid programs that might be open to him. And once at Hopkins, he still struggled financially. “I knew classmates who just got new laptops when theirs broke, but I basically saved everything I had to buy a Chromebook, which couldn’t even run all the programs I needed for class,” he recalls.

    “I feel like I need to pay forward all the opportunities and help that have been provided to me,” he says. “That’s why I’ve been involved with programs such the MIT Summer Research Program, which aims to increase diversity in science by bringing students from underrepresented backgrounds to MIT to do research.”

    “If you can, you do”

    Knippel’s mother has also helped propel him on his path to academia. She had been attending university on a musical scholarship, but ultimately left before graduating, when he was born. With his biological father out of the picture, he lived with his mother and her friend in a trailer for the first years of his life. The friend would provide childcare while his mother took longer shifts at work in order to spend more time with him. Eventually his mother got married and the family settled in Two Rivers, Wisconsin, where he went to middle and high school.

    “My education was always the most important thing to her,” he says of his mother. “She chose to stop her education because she had me, and just put all that energy into me.” He recalls how she put a bookshelf in the trailer and would scope out every garage sale in order to fill it with books. She also pushed him to apply to schools out of state, when many students in the area went to the state university. “It’s important that if you can, you do,” he remembers her insisting.

    His years as a teaching assistant and his relationship with his mentor drew Knippel into teaching himself. The summer after college, before starting his job at Genentech, he worked as a lecturer at Montgomery College, a community college in Maryland, teaching organic chemistry to underrepresented and nontraditional students. He’s still in contact with some of them –– even helping them apply to graduate schools.

    He’s still contemplating teaching as a career, although he’s also intrigued by the possibilities of working at places like Genentech, where the development of a drug could save thousands of lives. But Knippel, who is in the third year of his PhD program, still has some time to decide. “I don’t want to rule anything out,” he says.

    See the full article here .


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    Please help promote STEM in your local schools.


    Stem Education Coalition

    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    MIT Campus

     
  • richardmitnick 3:34 pm on December 10, 2018 Permalink | Reply
    Tags: GUSTO-Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory, , , Organic chemistry, , Selected by NASA, Terahertz laser for sensing and imaging outperforms its predecessors   

    From MIT News: “Terahertz laser for sensing and imaging outperforms its predecessors” 

    MIT News
    MIT Widget

    From MIT News

    December 10, 2018
    Rob Matheson

    1
    A tiny terahertz laser designed by MIT researchers is the first to reach three key performance goals at once: high power, tight beam, and broad frequency tuning.
    Courtesy of the researchers

    High-power, tunable design could be used for chemical detection in outer space, medical imaging, more.

    A terahertz laser designed by MIT researchers is the first to reach three key performance goals at once — high constant power, tight beam pattern, and broad electric frequency tuning — and could thus be valuable for a wide range of applications in chemical sensing and imaging.

    The optimized laser can be used to detect interstellar elements in an upcoming NASA mission that aims to learn more about our galaxy’s origins. Here on Earth, the high-power photonic wire laser could also be used for improved skin and breast cancer imaging, detecting drugs and explosives, and much more.

    The laser’s novel design pairs multiple semiconductor-based, efficient wire lasers and forces them to “phase lock,” or sync oscillations. Combining the output of the pairs along the array produces a single, high-power beam with minimal beam divergence. Adjustments to the individual coupled lasers allow for broad frequency tuning to improve resolution and fidelity in the measurements. Achieving all three performance metrics means less noise and higher resolution, for more reliable and cost-effective chemical detection and medical imaging, the researchers say.

    “People have done frequency tuning in lasers, or made a laser with high beam quality, or with high continuous wave power. But each design lacks in the other two factors,” says Ali Khalatpour, a graduate student in electrical engineering and computer science and first author on a paper describing the laser, published today in Nature Photonics. “This is the first time we’ve achieved all three metrics at the same time in chip-based terahertz lasers.”

    “It’s like ‘one ring to rule them all,’” Khalatpour adds, referring to the popular phrase from “The Lord of the Rings.”

    Joining Khalatpour on the paper are: Qing Hu, a distinguished professor of electrical engineering and computer science at MIT who has done pioneering work on terahertz quantum cascade lasers; and John L. Reno of the Sandia National Laboratories.

    Selected by NASA

    Last year, NASA announced the Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory (GUSTO), a 2021 mission to send a high-altitude balloon-based telescope carrying photonic wire lasers for detecting oxygen, carbon, and nitrogen emissions from the “interstellar medium,” the cosmic material between stars. Extensive data gathered over a few months will provide insight into star birth and evolution, and help map more of the Milky Way and nearby Large Magellanic Cloud galaxies.

    For a component of the GUSTO chemical detector, NASA selected a novel semiconductor-based terahertz laser previously designed by the MIT researchers. It is currently the best-performing terahertz laser. Such lasers are uniquely suited for spectroscopic measurement of oxygen concentrations in terahertz radiation, the band of the electromagnetic spectrum between microwaves and visible light.

    Terahertz lasers can send coherent radiation into a material to extract the material’s spectral “fingerprint.” Different materials absorb terahertz radiation to different degrees, meaning each has a unique fingerprint that appears as a spectral line. This is especially valuable in the 1-5 terahertz range: For contraband detection, for example, heroin’s signature is seen around 1.42 and 3.94 terahertz, and cocaine’s at around 1.54 terahertz.

    For years, Hu’s lab has been developing novel types of quantum cascade lasers, called “photonic wire lasers.” Like many lasers, these are bidirectional, meaning they emit light in opposite directions, which makes them less powerful. In traditional lasers, that issue is easily remedied with carefully positioned mirrors inside the laser’s body. But it’s very difficult to fix in terahertz lasers, because terahertz radiation is so long, and the laser so small, that most of the light travels outside the laser’s body.

    In the laser selected for GUSTO, the researchers had developed a novel design for the wire lasers’ waveguides — which control how the electromagnetic wave travels along the laser — to emit unidirectionally. This achieved high efficiency and beam quality, but it didn’t allow frequency tuning, which NASA required.

    Taking a page from chemistry

    Building on their previous design, Khalatpour took inspiration from an unlikely source: organic chemistry. While taking an undergraduate class at MIT, Khalatpour took note of a long polymer chain with atoms lined along two sides. They were “pi-bonded,” meaning their molecular orbitals overlapped to make the bond more stable. The researchers applied the concept of pi-bonding to their lasers, where they created close connections between otherwise-independent wire lasers along an array. This novel coupling scheme allows phase-locking of two or multiple wire lasers.

    To achieve frequency tuning, the researchers use tiny “knobs” to change the current of each wire laser, which slightly changes how light travels through the laser — called the refractive index. That refractive index change, when applied to coupled lasers, creates a continuous frequency shift to the pair’s center frequency.

    For experiments, the researchers fabricated an array of 10 pi-coupled wire lasers. The laser operated with continuous frequency tuning in a span of about 10 gigahertz, and a power output of roughly 50 to 90 milliwatts, depending on how many pi-coupled laser pairs are on the array. The beam has a low beam divergence of 10 degrees, which is a measure of how much the beam strays from its focus over distances.

    The researchers are also currently building a system for imaging with high dynamic range — greater than 110 decibels — which can be used in many applications such as skin cancer imaging. Skin cancer cells absorb terahertz waves more strongly than healthy cells, so terahertz lasers could potentially detect them. The lasers previously used for the task, however, are massive and inefficient, and not frequency-tunable. The researchers’ chip-sized device matches or outstrips those lasers in output power, and offers tuning capabilities.

    “Having a platform with all those performance metrics together … could significantly improve imaging capabilities and extend its applications,” Khalatpour says.

    “This is very nice work — in the THz [range] it has been very difficult to obtain high power levels from lasers simultaneous with good beam patterns,” says Benjamin Williams, associate professor of physical and wave electronics at the University of California at Los Angeles. “The innovation is the novel way they have used to couple the multiple wire lasers together. This is tricky, since if all of the lasers in the array don’t radiate in phase, then the beam pattern will be ruined. They have shown that by properly spacing adjacent wire lasers, they can be coaxed into ‘wanting’ to operate in a coherent symmetric supermode — all collectively radiating together in lockstep. As a bonus, the laser frequency can be tuned … to the desired wavelength — an important feature for spectroscopy and … for astrophysics.”

    See the full article here .


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    Please help promote STEM in your local schools.


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    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 5:53 pm on November 12, 2018 Permalink | Reply
    Tags: , , , MicroED-micro-electron diffraction, , NMR-nuclear magnetic resonance, Organic chemistry, , ,   

    From Caltech: “From Beaker to Solved 3-D Structure in Minutes” 

    Caltech Logo

    From Caltech

    11/12/2018

    Whitney Clavin
    (626) 395-1856
    wclavin@caltech.edu

    1
    Graduate student Tyler Fulton prepares samples of small molecules in a lab at Caltech. Credit: Caltech

    2
    Close-up of a powder containing small molecules like those that gave rise to 3-D structures in the new study. (The copper piece is a sample holder used with microscopes.) Credit: Caltech/Stoltz Lab

    3
    Brian Stoltz and Tyler Fulton. Credit: Caltech

    UCLA/Caltech team uncovers a new and simple way to learn the structures of small molecules.

    In a new study that one scientist called jaw-dropping, a joint UCLA/Caltech team has shown that it is possible to obtain the structures of small molecules, such as certain hormones and medications, in as little as 30 minutes. That’s hours and even days less than was possible before.

    The team used a technique called micro-electron diffraction (MicroED), which had been used in the past to learn the 3-D structures of larger molecules, specifically proteins. In this new study, the researchers show that the technique can be applied to small molecules, and that the process requires much less preparation time than expected. Unlike related techniques—some of which involve growing crystals the size of salt grains—this method, as the new study demonstrates, can work with run-of-the-mill starting samples, sometimes even powders scraped from the side of a beaker.

    “We took the lowest-brow samples you can get and obtained the highest-quality structures in barely any time,” says Caltech professor of chemistry Brian Stoltz, who is a co-author on the new study, published in the journal ACS Central Science. “When I first saw the results, my jaw hit the floor.” Initially released on the pre-print server Chemrxiv in mid-October, the article has been viewed more than 35,000 times.

    The reason the method works so well on small-molecule samples is that while the samples may appear to be simple powders, they actually contain tiny crystals, each roughly a billion times smaller than a speck of dust. Researchers knew about these hidden microcrystals before, but did not realize they could readily reveal the crystals’ molecular structures using MicroED. “I don’t think people realized how common these microcrystals are in the powdery samples,” says Stoltz. “This is like science fiction. I didn’t think this would happen in my lifetime—that you could see structures from powders.”

    4
    This movie [animated in the full article] is an example of electron diffraction (MicroED) data collection, in which electrons are fired at a nanocrystal while being continuously rotated. Data from the movie are ultimately converted to a 3-D chemical structure. Credit: UCLA/Caltech

    The results have implications for chemists wishing to determine the structures of small molecules, which are defined as those weighing less than about 900 daltons. (A dalton is about the weight of a hydrogen atom.) These tiny compounds include certain chemicals found in nature, some biological substances like hormones, and a number of therapeutic drugs. Possible applications of the MicroED structure-finding methodology include drug discovery, crime lab analysis, medical testing, and more. For instance, Stoltz says, the method might be of use in testing for the latest performance-enhancing drugs in athletes, where only trace amounts of a chemical may be present.

    “The slowest step in making new molecules is determining the structure of the product. That may no longer be the case, as this technique promises to revolutionize organic chemistry,” says Robert Grubbs, Caltech’s Victor and Elizabeth Atkins Professor of Chemistry and a winner of the 2005 Nobel Prize in Chemistry, who was not involved in the research. “The last big break in structure determination before this was nuclear magnetic resonance spectroscopy, which was introduced by Jack Roberts at Caltech in the late ’60s.”

    Like other synthetic chemists, Stoltz and his team spend their time trying to figure out how to assemble chemicals in the lab from basic starting materials. Their lab focuses on such natural small molecules as the fungus-derived beta-lactam family of compounds, which are related to penicillins. To build these chemicals, they need to determine the structures of the molecules in their reactions—both the intermediate molecules and the final products—to see if they are on the right track.

    One technique for doing so is X-ray crystallography, in which a chemical sample is hit with X-rays that diffract off its atoms; the pattern of those diffracting X-rays reveals the 3-D structure of the targeted chemical. Often, this method is used to solve the structures of really big molecules, such as complex membrane proteins, but it can also be applied to small molecules. The challenge is that to perform this method a chemist must create good-sized chunks of crystal from a sample, which isn’t always easy. “I spent months once trying to get the right crystals for one of my samples,” says Stoltz.

    Another reliable method is NMR (nuclear magnetic resonance), which doesn’t require crystals but does require a relatively large amount of a sample, which can be hard to amass. Also, NMR provides only indirect structural information.

    Before now, MicroED—which is similar to X-ray crystallography but uses electrons instead of X-rays—was mainly used on crystallized proteins and not on small molecules. Co-author Tamir Gonen, an electron crystallography expert at UCLA who began developing the MicroED technique for proteins while at the Howard Hughes Medical Institute in Virginia, said that he only started thinking about using the method on small molecules after moving to UCLA and teaming up with Caltech.

    “Tamir had been using this technique on proteins, and just happened to mention that they can sometimes get it to work using only powdery samples of proteins,” says Hosea Nelson (PhD ’13), an assistant professor of chemistry and biochemistry at UCLA. “My mind was blown by this, that you didn’t have to grow crystals, and that’s around the time that the team started to realize that we could apply this method to a whole new class of molecules with wide-reaching implications for all types of chemistry.”

    The team tested several samples of varying qualities, without ever attempting to crystallize them, and were able to determine their structures thanks to the samples’ ample microcrystals. They succeeded in getting structures for ground-up samples of the brand-name drugs Tylenol and Advil, and they were able to identify distinct structures from a powdered mixture of four chemicals.

    The UCLA/Caltech team says it hopes this method will become routine in chemistry labs in the future.

    “In our labs, we have students and postdocs making totally new and unique molecular entities every day,” says Stoltz. “Now we have the power to rapidly figure out what they are. This is going to change synthetic chemistry.”

    The study was funded by the National Science Foundation, the National Institutes of Health, the Department of Energy, a Beckman Young Investigators award, a Searle Scholars award, a Pew Scholars award, the Packard Foundation, the Sloan Foundation, the Pew Charitable Trusts, and the Howard Hughes Medical Institute. Other co-authors include Christopher Jones,Michael Martynowycz, Johan Hattne, and Jose Rodriguez of UCLA; and Tyler Fulton of Caltech.

    See the full article here .


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  • richardmitnick 5:36 pm on January 10, 2018 Permalink | Reply
    Tags: , , , , , , , , , Organic chemistry, STXM-scanning transmission X-ray microscope, We’re looking at the organic ingredients that can lead to the origin of life” including the amino acids needed to form proteins,   

    From LBNL: “Ingredients for Life Revealed in Meteorites That Fell to Earth” 

    Berkeley Logo

    Berkeley Lab

    January 10, 2018
    Glenn Roberts Jr.
    geroberts@lbl.gov
    (510) 486-5582

    1
    A blue crystal recovered from a meteorite that fell near Morocco in 1998. The scale bar represents 200 microns (millionths of a meter). (Credit: Queenie Chan/The Open University, U.K.)

    Two wayward space rocks, which separately crashed to Earth in 1998 after circulating in our solar system’s asteroid belt for billions of years, share something else in common: the ingredients for life. They are the first meteorites found to contain both liquid water and a mix of complex organic compounds such as hydrocarbons and amino acids.

    A detailed study of the chemical makeup within tiny blue and purple salt crystals sampled from these meteorites, which included results from X-ray experiments at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), also found evidence for the pair’s past intermingling and likely parents. These include Ceres, a brown dwarf planet that is the largest object in the asteroid belt, and the asteroid Hebe, a major source of meteorites that fall on Earth.

    The study, published Jan. 10 in the journal Science Advances, provides the first comprehensive chemical exploration of organic matter and liquid water in salt crystals found in Earth-impacting meteorites. The study treads new ground in the narrative of our solar system’s early history and asteroid geology while surfacing exciting possibilities for the existence of life elsewhere in Earth’s neighborhood.

    “It’s like a fly in amber,” said David Kilcoyne, a scientist at Berkeley Lab’s Advanced Light Source (ALS), which provided X-rays that were used to scan the samples’ organic chemical components, including carbon, oxygen, and nitrogen.

    LBNL/ALS

    Kilcoyne was part of the international research team that prepared the study.

    While the rich deposits of organic remnants recovered from the meteorites don’t provide any proof of life outside of Earth, Kilcoyne said the meteorites’ encapsulation of rich chemistry is analogous to the preservation of prehistoric insects in solidified sap droplets.

    Queenie Chan, a planetary scientist and postdoctoral research associate at The Open University in the U.K. who was the study’s lead author, said, “This is really the first time we have found abundant organic matter also associated with liquid water that is really crucial to the origin of life and the origin of complex organic compounds in space.”

    She added, “We’re looking at the organic ingredients that can lead to the origin of life,” including the amino acids needed to form proteins.

    If life did exist in some form in the early solar system, the study notes that these salt crystal-containing meteorites raise the “possibility of trapping life and/or biomolecules” within their salt crystals. The crystals carried microscopic traces of water that is believed to date back to the infancy of our solar system – about 4.5 billion years ago.

    Chan said the similarity of the crystals found in the meteorites – one of which smashed into the ground near a children’s basketball game in Texas in March 1998 and the other which hit near Morocco in August 1998 – suggest that their asteroid hosts may have crossed paths and mixed materials.

    There are also structural clues of an impact – perhaps by a small asteroid fragment impacting a larger asteroid, Chan said.

    This opens up many possibilities for how organic matter may be passed from one host to another in space, and scientists may need to rethink the processes that led to the complex suite of organic compounds on these meteorites.

    “Things are not as simple as we thought they were,” Chan said.

    There are also clues, based on the organic chemistry and space observations, that the crystals may have originally been seeded by ice- or water-spewing volcanic activity on Ceres, she said.

    “Everything leads to the conclusion that the origin of life is really possible elsewhere,” Chan said. “There is a great range of organic compounds within these meteorites, including a very primitive type of organics that likely represent the early solar system’s organic composition.”

    Chan said the two meteorites that yielded the 2-millimeter-sized salt crystals were carefully preserved at NASA’s Johnson Space Center in Texas, and the tiny crystals containing organic solids and water traces measure just a fraction of the width of a human hair. Chan meticulously collected these crystals in a dust-controlled room, splitting off tiny sample fragments with metal instruments resembling dental picks.

    2
    These ALS X-ray images show organic matter (magenta, bottom) sampled from a meteorite, and carbon (top). (Credit: Berkeley Lab)

    “What makes our analysis so special is that we combined a lot of different state-of-the-art techniques to comprehensively study the organic components of these tiny salt crystals,” Chan said.

    Yoko Kebukawa, an associate professor of engineering at Yokohama National University in Japan, carried out experiments for the study at Berkeley Lab’s ALS in May 2016 with Aiko Nakato, a postdoctoral researcher at Kyoto University in Japan. Kilcoyne helped to train the researchers to use the ALS X-ray beamline and microscope.

    The beamline equipped with this X-ray microscope (a scanning transmission X-ray microscope, or STXM) is used in combination with a technique known as XANES (X-ray absorption near edge structure spectroscopy) to measure the presence of specific elements with a precision of tens of nanometers (tens of billionths of a meter).

    “We revealed that the organic matter was somewhat similar to that found in primitive meteorites, but contained more oxygen-bearing chemistry,” Kebukawa said. “Combined with other evidence, the results support the idea that the organic matter originated from a water-rich, or previously water-rich parent body – an ocean world in the early solar system, possibly Ceres.”

    Kebukawa also used the same STXM technique to study samples at the Photon Factory, a research site in Japan. And the research team enlisted a variety of other chemical experimental techniques to explore the samples’ makeup in different ways and at different scales.

    Chan noted that there are some other well-preserved crystals from the meteorites that haven’t yet been studied, and there are plans for follow-up studies to identify if any of those crystals may also contain water and complex organic molecules.

    3
    Ceres, a dwarf planet in the asteroid belt pictured here in this false-color image, may be the source of organic matter found in two meteorites that crashed to Earth in 1998. (Credit: NASA)

    Kebukawa said she looks forward to continuing studies of these samples at the ALS and other sites: “We may find more variations in organic chemistry.”

    The Advanced Light Source is a DOE Office of Science User Facility.

    Scientists at NASA Johnson Space Center, Kochi Institute for Core Sample Research in Japan, Carnegie Institution of Washington, Hiroshima University, The University of Tokyo, the High-Energy Accelerator Research Organization (KEK) in Japan, and The Graduate University for Advanced Studies (SOKENDAI) in Japan also participated in the study. The work was supported by the U.S. DOE Office of Science, the Universities Space Research Association, NASA, the National Institutes of Natural Sciences in Japan, Japan Society for the Promotion of Science, and The Mitsubishi Foundation.

    See the full article here .

    Please help promote STEM in your local schools.

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