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  • richardmitnick 1:01 pm on October 3, 2017 Permalink | Reply
    Tags: , , , Biomarkers, , , ,   

    From ESA: “Biomarker found in space complicates search for life on exoplanets” 

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    European Space Agency

    Comet 67P/Churyumov–Gerasimenko. No image credit.

    A molecule once thought to be a useful marker for life as we know it has been discovered around a young star and at a comet for the first time, suggesting these ingredients are inherited during the planet-forming phase.

    The discovery of methyl chloride was made by the ground-based Atacama Large Millimeter/submillimeter Array (ALMA) in Chile, and by ESA’s Rosetta spacecraft following Comet 67P/Churyumov–Gerasimenko. It is the simplest member of a class of molecules known as organohalogens, which contain halogens, such as chlorine or fluorine, bonded with carbon.

    Methyl chloride is well known on Earth as being used in industry. It is also produced naturally by biological and geological activity: it is the most abundant organohalogen in Earth’s atmosphere, with up to three megatonnes produced a year, primarily from biological processes.

    As such, it had been identified as a possible ‘biomarker’ in the search for life at exoplanets. This has been called into question, however, now it is seen in environments not derived from living organisms, and instead as a raw ingredient from which planets could eventually form.

    This is also the first time an organohalogen has been detected in space, indicating that halogen- and carbon-centred chemistries are more intertwined than previously thought.

    The ALMA observations were made towards the young star IRAS 16293-2422, a low-mass binary system in the Rho Ophiuchi star-forming region about 400 light-years from Earth.

    ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres

    The system was already known to have a wealth of organic molecules distributed around it, but ALMA now makes it possible to zoom in to scales equivalent to the outer planets in our own Solar System, making it an ideal target for comparative studies with comets.

    Because comets are believed to preserve the chemical composition of the Sun’s birth cloud, and in order to better understand the formation pathways of organic molecules, the detection of the molecule in the young star system triggered a search in the extensive data collected by ESA’s Rosetta spacecraft during its 2014–16 mission at Comet 67P/Churyumov–Gerasimenko.

    Because comets are believed to preserve the chemical composition of the Sun’s birth cloud, and in order to better understand the formation pathways of organic molecules, the detection of the molecule in the young star system triggered a search in the extensive data collected by ESA’s Rosetta spacecraft during its 2014–16 mission at Comet 67P/Churyumov–Gerasimenko.

    ESA/Rosetta spacecraft

    “We found it but it is very elusive, one of the ‘chameleons’ of our molecule zoo, only present during short times when we observed a lot of chlorine,” says Kathrin Altwegg, principal investigator of the ROSINA instrument that made the comet detection.

    ESA Rosetta ROSINA

    The measurements were made in May 2015, when the comet was approaching its closest point to the Sun along its elliptical orbit, near to the orbit of Mars, and was very active, releasing a lot of gas and dust as the Sun warmed its icy surface. The methyl chloride was identified in the measurements when the hydrogen chloride signal was at its highest.

    Delivering ingredients to Earth. Released 02/10/2017. Copyright ESA

    Our Solar System condensed from a cloud of gas and dust over 4.6 billion years ago. As the newborn planets settled in their orbits, gravitational perturbations are thought to have disrupted swarms of comets into the inner Solar System, impacting the rocky planets. As well as inheriting ingredients during the planet-forming process itself, comets are also believed to have delivered some of the basic ingredients for life to Earth, leading to life as we know it today.

    Moreover, the methyl chloride was found in comparable abundances in both the young star system and the comet. Rocky planets like Earth could directly inherit these ingredients during the planet-building phase, but comets could also act as a vessel to deliver them through the high rate of impacts occurring in the early years of a forming solar system.

    “The dual detection of an organohalogen in a star-forming region and at a comet indicates that these chemicals will likely be part of the ‘primordial soup’ on the young Earth and newly formed rocky exoplanets,” says Edith Fayolle, lead author of the study published in Nature Astronomy. “Understanding this initial chemistry on planets is an important step toward the origins of life.”

    It is also a crucial aspect for the search for life outside our Solar System, but the apparent prevalence of organohalogens in space calls into question their use as a biomarker when interpreting possible future detections of the molecule in the atmospheres of rocky exoplanets.

    “The combined study takes detections of key biological molecules to a new level, with the exciting possibility that they predate the formation of our Solar System as we know it today,” comments Matt Taylor, ESA’s Rosetta project scientist.

    “The complementary results provide an important context for our Rosetta data and for the wider implications of Solar System formation, and especially how we might interpret observations of extrasolar systems.”

    Notes for Editors

    Protostellar and cometary detections of organohalogens, by E. Fayolle et al. is published in Nature Astronomy, 2 October 2017.

    The ALMA data were part of the Protostellar Interferometric Line Survey (PILS). The aim of the survey is to chart the chemical complexity of IRAS 16293-2422 by imaging the full wavelength range covered by ALMA on very small scales, equivalent to the size of our Solar System.

    ALMA is an international astronomy facility, and a partnership between the European Southern Observatory, the US National Science Foundation and the National Institutes of Natural Sciences of Japan in collaboration with the Republic of Chile. More about ALMA partners.

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 11:14 am on August 17, 2016 Permalink | Reply
    Tags: A tiny wire with a memory to diagnose cancer, , Biomarkers, , ,   

    From EPFL: “A tiny wire with a memory to diagnose cancer” 

    EPFL bloc

    École Polytechnique Fédérale de Lausanne EPFL

    Laure-Anne Pessina

    A nanowire can detect cancer © I2016 Thinkstock

    EPFL researchers have used a nanowire to detect prostate cancer with greater accuracy than ever before. Their device is ten times more sensitive than any other biosensor available.

    One indicator that a cancer has started to develop is the presence of biomarkers. These are molecules that are produced by the cancer and pass into the bloodstream.

    Researchers at EPFL’s Integrated Systems Laboratory (LSI/STI) have developed a new type of sensor that can detect tiny quantities of these markers and thus improve diagnostic accuracy. The sensor comes in the form of a tiny wire and is ten times more sensitive than any other biosensor ever realized. It is therefore capable of detecting cancer at a very early stage so that patients can receive better treatment. The researchers’ work has been published in Nano Letters.

    An electrical component with a memory

    When doctors suspect that a patient has cancer, they look for biomarkers in their body. But it’s not easy to detect these molecules in very small quantities – blood is a very dense fluid, full of molecules and cells that get in the way.

    EPFL researchers have managed to get around this obstacle by inventing a new detection technique. The trick is to trap the molecules of interest by the blood sample and then detect them in a dry environment, where measurements won’t be disturbed by all the molecules. To do this, the researchers used a Memristor – a new electrical component that can “remember” all the electrical currents that pass through it. The device has been successfully tested on the biomarker for prostate cancer, known as the Prostate Specific Antigen (PSA).

    A nanowire, DNA fragments and an electric current

    To begin with, fragments of modified DNA are grafted onto a silicon nanowire. The DNA is used to trap the molecules. It is modified so that it traps only the biomarkers for prostate cancer.

    The wire is dipped into a cancer sample for close to an hour, giving the DNA time to get hold of the molecules. It is then dried and an electric charge is first sent through it. If there are molecules on the wire, they create resistance, which alters the wire’s conductivity in places. But this alone is not enough to accurately detect the biomarkers.

    It is only when the same charge is sent through the wire a second time in the opposite direction that the molecules can be properly detected. “If the wire had no memory, the two currents’ curves would be superimposed, which means there’s no memory effect,” said Sandro Carrara, from the Integrated Systems Lab.

    If the right biomarkers are trapped at the wire surface, then at the exact spot where the current reverse during the phases of sending charges into the wire, there will be a difference in the curve known as a voltage gap. It is this phenomenon that makes it possible to detect the biomarkers with so high sensitivity together with the use of modified DNA to trap the biomarkers.

    “It’s the first time a Memristor has been used to make such type of biosensor,” said Carrara.

    For now, the technique has only been used to detect biomarkers for prostate cancer. But it could be used for all types of markers. “We are also working with the Ludwig Institute and the CHUV hospital, which are providing us with samples and tumor extracts. Our next step is to use the same technique to detect breast cancer.”


    Project partners:

    Experimental Oncology Group, Ludwig Institute for Cancer Research (Lausanne)
    Senology Unit, Department of Obstetrics and Gynecology, CHUV hospital (Lausanne)
    Department of Electronic & Electrical Engineering, University of Bath (United Kingdom)
    Department of Informatics and Microsystem Technology, University of Applied Sciences Kaiserslautern, Zweibrücken (Germany)

    See the full article here .

    Please help promote STEM in your local schools.

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    Stem Education Coalition

    EPFL campus

    EPFL is Europe’s most cosmopolitan technical university with students, professors and staff from over 120 nations. A dynamic environment, open to Switzerland and the world, EPFL is centered on its three missions: teaching, research and technology transfer. EPFL works together with an extensive network of partners including other universities and institutes of technology, developing and emerging countries, secondary schools and colleges, industry and economy, political circles and the general public, to bring about real impact for society.

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