The scientists, Konstantinos Iliopoulos and coauthors from the University of Angers, France, have published their study in a recent issue of the Journal of the American Chemical Society. The researchers designed a new class of nonlinear optical (NLO) coumarin-based polymers that can be reversibly transformed into dimers (which are large molecules made of two identical smaller molecules) under irradiation by different wavelengths of light. Whereas wavelengths greater than 300 nm can produce dimers, wavelengths less than 280 nm do the reverse, separating each dimer into two individual molecules. Since each type of molecule is electronically and structurally very different, optically controlling this process can provide the basis for writing, reading, erasing, and rewriting data.“The most important issue is the conjugation of several aspects in one system,” coauthor Denis Gindre of the University of Angers told PhysOrg.com. “First, a high density of data storage; second, re-writability; and third, the fact that these issues can only be addressed by a non-linear technique (and are non-detectable by linear techniques).” To demonstrate the possibility of writing data in this way, the scientists irradiated a coumarin-based polymer with a laser with a wavelength of 700 nm (for a two-photon process at 350 nm). The laser created a photodimerization reaction of the coumarin molecules, changing the polymer into a dimer form. By controlling the irradiation, the scientists demonstrated the recording of lines and dots.The recorded data could be read by a method called second-harmonic generation (SHG)-assisted imaging, in which photons interacting with the NLO material combine to form photons with twice the energy. The level of SHG signals is significantly lower than the unwritten background area, resulting in two distinct logical levels. No loss of recorded bits along the reading process was observed because the UV light generated by SHG is not absorbed by the molecules, avoiding the erasing of information by further chemical reaction.Finally, the scientists showed that the data could be erased and rewritten in the same area. To erase, the written polymer was exposed to a UV light with a wavelength of less than 280 nm, which converted the dimer polymer back into its original form. After using SHG imaging to confirm that the data was erased, the scientists repeated the writing process with the longer-wavelength laser. This novel approach to optical data storage has the potential to provide an efficient, high-capacity data storage method, the scientists note. Also, because the reading process can be carried out only by SHG imaging, the technique could be used for the sensitive field of hidden 3D data storage.“This technique can, in principle, be applied to a bulk 3D material,” said coauthor Marc Sallé of the University of Angers. “With such a concept, it is impossible to read the written information with conventional linear techniques like optical microscopy, polarization microscopy, atomic force microscopy, and so on. This is why the term ‘hidden’ was used. One potential application is, for instance, undetectable marking to detect fakes or counterfeits.” This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Five-Dimensional DVD Could Hold Data of 30 Blu-ray Discs Explore further (Top) The image in (a) shows lines written using the photodimerization technique, corresponding to lower SHG signals in (b). (Bottom) These images show a line that was (a) written, (b) erased, and (c) rewritten perpendicular to the first line. Image credit: Iliopoulos, et al. © 2010 American Chemical Society. More information: Konstantinos Iliopoulos, et al. “Reversible Two-Photon Optical Data Storage in Coumarin-Based Copolymers.” Journal of the American Chemical Society, Article ASAP. DOI: 10.1021/ja1047285 Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Citation: Scientists propose ‘hidden’ 3D optical data storage technique (2010, October 13) retrieved 18 August 2019 from https://phys.org/news/2010-10-scientists-hidden-3d-optical-storage.html (PhysOrg.com) — By using a laser to reversibly combine and separate molecules, scientists have demonstrated a new optical data storage technique. Because the data can be read by only one kind of imaging technique (second-harmonic generation-assisted imaging), the new method could be used for hidden 3D data storage.
Citation: The Virus Turns 40 (2011, March 15) retrieved 18 August 2019 from https://phys.org/news/2011-03-virus.html Statistical physics shows new approach to fighting viruses More information: You can find more information about the most intriguing viruses over the last 40 years and how they’ve evolved over time here. (PhysOrg.com) — Today we have the dubious honor of wishing a happy birthday to the computer virus. It is hitting its 40th birthday, so get out the grim reaper cake and “Over the Hill” balloons. While we certainly won’t be wishing the virus many happy returns, we can get a look at how the virus has evolved over time. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2010 PhysOrg.com Explore further You may be wondering what the first virus was? As it turns out that the first virus was created in 1971, and was promptly given the name Creeper. The Creeper most noticeable side effect was when the virus displayed the message “I’m the creeper, catch me if you can!” on the screens of the infected machines. Scooby Doo fans may also remember this name from another campy 70’s creation. A villain named The Creeper made an appearance in the animated film Scoobie Doo and the Ghoul School.Bad 70’s jokes aside, and trust me with those hairstyles and mustaches this reporter could go on for at least another 500 words, this virus was the beginning of the digital war that we are living in today: where companies try harder and harder to shore up the holes in their operating systems while the creators of malicious code work their hardest to exploit them. This war is about more than simple exploitation, it is a numbers game as well. When you consider that viruses have grown from 1,300 viruses in 1990 to over 200 million computer viruses on the web currently, we can see how things have grown exponentially.And while the amount was changing, the nature was too. Early viruses were simply an annoyance, done mostly to prove that the designer could. Current models are usually designed with another type of crime in mind, usually identity theft or creating a botnet. The first virus to really exploit the commercial potential of the virus was the Melissa, which ran rampant in 1999, and the first virus to make botnets came about in 2005. It was named MyTob.You may be wondering, on this anniversary what will be the next frontier for the virus? Most experts predict that it will be smartphones.
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Copyright 2011 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. The researchers, Joel K. W. Yang, et al., from the Institute of Materials Research and Engineering and the Data Storage Institute at A*STAR (the Agency for Science, Technology and Research) in Singapore, as well as the National University of Singapore, have published their study in a recent issue of Nanotechnology. As Yang explained, the new method pushes the boundaries of hard disk drive recording densities.“Yes, 3.3 Tbit/in2 is one of the highest demonstrations to date,” Yang told PhysOrg.com. “Though there are other non-magnetic patterns that have higher densities, we believe we’ve fabricated and tested magnetic bits that are the most densely packed.”Today’s hard disk drives have recording densities of up to 0.5 Tbit/in2, but improving this density beyond 1-1.5 Tbit/in2 may not be possible using the same granular method. The difficulty stems from two limits. The first is a limit on the minimum number of grains per bit (each bit requires at least a few tens of grains), which is due to the need for a sufficient signal-to-noise ratio. The second limit is the superparamagnetic limit, which limits the minimum grain size. If the grain size is too small, the magnetization state becomes thermally unstable and the grains can no longer store data.In contrast with the conventional method, patterned media (or bit-patterned media) doesn’t face the same limits. Because the magnetic cells are lithographically patterned in ordered arrays, the signal-to-noise ratio is significantly improved, and each individual magnetic cell can serve as a bit. And since the magnetic cells are larger than the grains, they don’t run into the superparamagnetic limit. By overcoming the limitations of granular media, patterned media has the potential for achieving recording densities well beyond 1 Tbit/in2. Some patterned media techniques have even demonstrated original pattern resolutions of up to 10 Tdot/in2 (before the dots become functional bits), but these fabrication techniques rely on pattern-transfer methods such as etching or liftoff that degrade the resolution of the original pattern, and reduce the final density. (a, b) In the first step of the process, tiny pillars are patterned onto a surface. (c, d) In the second step, a magnetic film is deposited onto the posts, turning them into magnetic bits. The 35-nm spacing corresponds to a recording density of 0.6 Tbit/in2. A sample with 15-nm spacing (not shown) corresponds to a recording density of 3.3 Tbit/in2. Image credit: Yang, et al. ©2011 IOP Publishing Ltd More information: Joel K W Yang, et al. “Fabrication and characterization of bit-patterned media beyond 1.5 Tbit/in2.” Nanotechnology 22 (2011) 385301 (6pp). DOI:10.1088/0957-4484/22/38/385301 ‘3-D towers’ of information double data storage areal density (PhysOrg.com) — In an effort to increase the recording densities of hard disk drives, patterned media has become one of the most promising strategies for achieving recording densities beyond 1 Tbit/in2. In patterned media, data is stored in a uniform array of magnetic cells that each contain one bit, rather than in groups of randomly arranged magnetic nanograins in a thin-film magnetic alloy, as in today’s hard disk drives. In a new study, researchers have developed a simplified patterned media method by reducing the number of steps in the process, and have demonstrated high densities from 1.9 Tbit/in2 to 3.3 Tbit/in2, although the latter density still needs to be characterized by higher resolution magnetic force microscopes than were available for the study. Explore further Citation: Patterned media technique achieves Terabit data recording densities (2011, September 6) retrieved 18 August 2019 from https://phys.org/news/2011-09-patterned-media-technique-terabit-densities.html To address the pattern-transfer problem, the researchers from Singapore have developed a patterned media process that doesn’t require any kind of pattern transfer. Their technique consists of just two steps: (1) using electron beam lithography to pattern arrays of dots (or tiny pillars) as small as 10 nm in diameter on a resist material, and (2) using sputtering techniques to deposit 21-nm-thick magnetic films on top of the entire resist material. The magnetic material that lands on top of the nanoposts serves as magnetically isolated bits. By avoiding etching and liftoff processes, the resolution of the final patterns are basically identical to the resolution of the original lithographic pattern.“The etching step could be avoided as the e-beam pattern resist itself, while being an excellent imaging medium for the electron beam, doubles up as a robust material that can be used in hard-disk platters,” Yang explained.Using the new method, the researchers fabricated samples with a patterning density of up to 3.3 Tdot/in2, and scanning-electron microscope images showed that the final magnetic bits maintain the same densities, up to 3.3 Tbit/in2. Because the magnetic bits are physically connected to their neighbors by tiny magnetic links, the researchers had to confirm that the individual bits were still magnetically isolated and that these links did not interfere with each bit’s ability to store data. To do this, they observed the samples under a magnetic force microscope while applying magnetic fields of different strengths to switch individual bits. For samples with densities up to 1.9 Tbit/in2, the microscope showed that individual bits can be switched independently of their neighbors; beyond that, the microscope could not resolve individual bits due to its own resolution limit.“The biggest advantage of this technique is that the final density/resolution of the fabricated bits were kept as close as possible to that of the lithographic step,” Yang said. “If we had introduced pattern-transfer steps such as etching, the maximum achievable resolution would be significantly lower due to pattern degradation during etching. As a bonus, reducing steps also reduces cost and increases throughput, especially when combined with high-throughput processes such as nanoimprint lithography and guided self-assembly.”The researchers predict that higher resolution magnetic force microscope techniques will verify the individual switchability of the bits at 3.3 Tbit/in2. They also predict that the new patterned media technique can enable the fabrication of memories at the highest possible densities (in the range of 10 Tbit/in2). If the electron beam lithography step can be combined with, or replaced by, other scalable patterning methods such as templated self-assembly, the new technique could be used for the large-scale manufacturing of future ultrahigh-density hard disk drives.
The researchers, Jian Liang and Giacinto Scoles from Temple University in Philadelphia, Pennsylvania, and Matteo Castronovo from Temple University and CRO-National Center Institute in Aviano Pordenone, Italy, have published their work on using DNA as invisible ink in a recent issue of the Journal of the American Chemical Society. To write with DNA as invisible ink, the scientists used a nanolithography technique called nanografting, in which nanostructures are written using an atomic force microscope. Unlike other nanolithography techniques, in which nanostructures are written on top of a surface, nanografting first removes the original molecules in the scanning region and then writes new molecules in their place. Using this technique, the scientists first covered a gold surface with a monolayer of thiolated single-stranded DNA (ssDNA) molecules using a self-assembly process. Then they embedded the same type of DNA using nanografting into the thiolated DNA background. At this point, the nanografted DNA pattern is invisible, as it has the same thickness and chemical makeup as the background. However, the nanografted DNA is different from the self-assembled DNA background in that the nanografted molecules have a tighter packing order. Although the packing order is invisible under the initial conditions, a tighter packing order makes the nanografted DNA more sensitive to hybridization. The scientists found that performing a hybridization process that involves immersing the DNA film in a fluid containing the complementary DNA (cDNA) increases the thickness of the nanografted DNA much more dramatically than that of the self-assembled DNA. As a result, the nanografted DNA pattern emerges and becomes visible.By dehybridizing the DNA film, the researchers could reverse the thickness increase and make the DNA pattern invisible again. To dehybridize, the researchers incubated the DNA film in ultrapure Milli-Q water for several hours, and the pattern disappeared. The researchers found that they could repeat the hybridization/dehybridization process multiple times, and the pattern could still be switched between visible (“on”) and invisible (“off”) with high fidelity.The scientists noted that this ability to write, read, and erase is not very common in nanolithography. This novelty makes the DNA invisible ink an intriguing discovery that could be used for manipulating biological molecules and generating new encryption technologies. The encryption ability could also be combined with other techniques such as DNA stamping, which allows patterns to be transferred using a programmable, reversible, and recyclable mold. (PhysOrg.com) — While most people know of DNA as the building blocks of life, these large molecules also have potential applications in areas such as biosensing, nanoparticle assembly, and building supramolecular structures. And now scientists have added another use to the list: invisible ink. More information: Jian Liang, et al. “DNA as Invisible Ink for AFM Nanolithography.” Journal of the American Chemical Society. DOI:10.1021/ja2076845 Explore further (A) ssDNA is nanografted into a background of self-assembled ssDNA, with both having the same height (“off” state). (B) Hybridizing the ssDNA reveals the hidden pattern (“on” state) due to the increased height of the nanografted DNA. (C) Dehybridizing reverses the height increase (“off state). (D) The pattern is restored. (E) and (F) show the height of the pattern in the “off” and “on” states, respectively. Image credit: Liang, et al. ©2011 American Chemical Society Citation: DNA as invisible ink can reversibly hide patterns (2012, January 23) retrieved 18 August 2019 from https://phys.org/news/2012-01-dna-invisible-ink-reversibly-patterns.html Journal information: Journal of the American Chemical Society Copyright 2012 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. DNA falls apart when you pull it
Citation: Adapteva $99 parallel processing boards targeted for summer (2013, April 22) retrieved 18 August 2019 from https://phys.org/news/2013-04-adapteva-parallel-boards-summer.html “We don’t have time to wait for the rest of the industry to come around to the fact that parallel computing is the only path forward and that we need to act now. We hope you will join us in our mission to change the way computers are built,” they had said when appealing earlier for support. The Lexington, Massachusetts, company has now announced they built the first Parallella board for Linux supercomputing. They made the announcement at the Linux Collaboration Summit in San Francisco earlier this month. (The summit is a gathering of core kernel developers, distribution maintainers, ISVs, end users, system vendors and various other community organizations.) The Linux distribution being used is Ubuntu 12.04 © 2013 Phys.org Adapteva’s board is the size of a credit card. This comes with a dual-core ARM A9 processor and a 64-core Epiphany Multicore Accelerator chip. Parallela’s details include 1GB of RAM, two USB 2.0 ports, a microSD slot, and an HDMI connection. Active components and the majority of the standard connectors are on the top side of the board. The expansion connectors and microSD card connector are at the bottom side of the board.Olofsson said the company’s first audience target is developers. “We need to make sure that every programmer has access to cheap and open parallel hardware and development tools,” said an Adapteva program note for the Linux event. Massively parallel computing will become truly ubiquitous once the vast majority of programmers and programs know how to take full advantage of the underlying hardware They see a critical need to close the knowledge gap in parallel programming. They said their targeted our second tier are the people who just want an awesome computer for $99.Platform reference design and drivers are now available. Explore further Information technology needs fundamental shift to continue rapid advances in computing The processor board running on Linux is called Parallella. According to the Kickstarter page, pledges totaled $898,921 from 4,965 backers when Adapteva set its goal for funding. The company decided to go through the crowdfunding route in order to produce the Parallella boards in volume. They sought funding for adequate tooling to accommodate volume, to make this board effort viable, to get the platform “out there.” The company’s hurry-up drive on making parallel processing access easier for more people has a sense of urgency because the company wants to speed adoption of parallel processing in the industry. Founded in 2008, the company’s chip technology has gained traction with government labs, corporate labs, and schools but getting large corporations to buy into parallel computing is challenging. They were convinced that the only way to create a sustainable parallel computing platform was through a grass roots movement. The company founder, Andreas Olofsson, said that parallel computing is the only way to scale to energy efficiency, performance, and cost. Systems, he stated, need to be parallel and they need to be open “Our 99 dollar kit is going to be completely open,” he said, and the Parallella open platform will educate the masses on how to do parallel computing. More information: www.parallella.org/2013/04/02/ … a-hardware-platform/www.parallella.org/2013/04/16/ … -name-is-parallella/ (Phys.org) —The semiconductor technology company Adapteva earlier this month featured its parallel-processing board for Linux supercomputingts at a major Linux event, and the board is targeted to ship this summer. The board will be going out to those who pledged money in last year’s Adapteva Kickstarter campaign and to other customers. Not a minute too soon. To hear the story of computing as Adapteva tells it, the future of computing is parallel. Big-data and other demands pose a processor challenge and Adapteva recognizes a problem in energy efficiency that is calling for action. Adapteva is on a mission to “democratize” access to parallel computing. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
After analyzing all the data, the researchers concluded that the winds that blow on both planets, due so in a very thin layer in the atmosphere—no more than 600 miles deep. Because of the large size of the planets, the layers are proportionally very small—just 0.15 percent of the mass of Uranus, and 0.2 percent for Neptune. This suggests, the researchers propose, that the winds are mostly driven by atmospheric and surface conditions (possibly moisture evaporating and condensing) rather than some forces deep inside the planets icy interior.Using gravity to estimate wind conditions on other planets is a new approach, one that will likely be applied to exoplanets now that it appears to have provided useful information about planets closer to home. This is an image from the Voyager 2 flyby of Neptune in August 1989 (NASA). In the middle is the Great Dark Spot, accompanied by bright, white clouds that undergo rapid changes in appearance. To the south of the Great Dark Spot is the bright feature that Voyager scientists nicknamed “Scooter.” Still farther south is the feature called “Dark Spot 2,” which has a bright core. As each feature moves eastward at a different velocity, they are rarely aligned this way. Wind velocities near the equator are westward, reaching 1300 km/h, while those at higher latitudes are eastward, peaking at 900 km/h. Credit: NASA More information: Atmospheric confinement of jet streams on Uranus and Neptune, Nature 497, 344–347 (16 May 2013) doi:10.1038/nature12131AbstractThe observed cloud-level atmospheric circulation on the outer planets of the Solar System is dominated by strong east–west jet streams. The depth of these winds is a crucial unknown in constraining their overall dynamics, energetics and internal structures. There are two approaches to explaining the existence of these strong winds. The first suggests that the jets are driven by shallow atmospheric processes near the surface, whereas the second suggests that the atmospheric dynamics extend deeply into the planetary interiors. Here we report that on Uranus and Neptune the depth of the atmospheric dynamics can be revealed by the planets’ respective gravity fields. We show that the measured fourth-order gravity harmonic, J4, constrains the dynamics to the outermost 0.15 per cent of the total mass of Uranus and the outermost 0.2 per cent of the total mass of Neptune. This provides a stronger limit to the depth of the dynamical atmosphere than previously suggested, and shows that the dynamics are confined to a thin weather layer no more than about 1,000 kilometres deep on both planets.Press release Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Jet streams on the planet Neptune. Credit: Yohai Kaspi/ Weizmann Institute of Science/ NASA With the downgrading of Pluto, Neptune and Uranus are now listed as the planet’s in our solar system the most distant from the sun. Because of that, the least is known about them. To date, just one spacecraft has flown close enough to either of them to offer useful information: Voyager 2 back in the 1980’s. Scientists would like to know more of course—of particular interest are the bands of winds that blow at high speeds in the atmospheres of both planets. Are they fueled by mostly atmospheric conditions or by an unknown inner planetary dynamic? No one knows for sure, but work done in this latest effort suggests it’s more likely the former.To learn more about the weather systems going on with both planets, the research team dug up gravity data from the Voyager 2 missions, used current telescopes and created models to help identify the factors that contribute to the wind bands. They focused specifically on each planets’ gravitational field, noting that variations can occur due to a variety of factors. Some of those include the amount of mass beneath a point being measured, how compressed the spherical nature of the planet is due to spin, and the amount of material held in the atmosphere by winds. Computer simulation shows Solar System once had an extra planet (Phys.org) —A team of researchers from the U.S. and Israel has deduced that the winds that blow on Uranus and Neptune are confined to relatively thin atmospheric layers. In their paper published in the journal Nature, the group describes how they used data from Voyager 2, ground based satellites and models to work out the thickness of the weather systems on the two ice giants. © 2013 Phys.org Citation: Researchers find winds on Uranus and Neptune confined to thin atmosphere layer (2013, May 16) retrieved 18 August 2019 from https://phys.org/news/2013-05-uranus-neptune-confined-thin-atmosphere.html Journal information: Nature
Observed data for event OGLE-2014-BLG-0676/MOA-2014-BLG-175 from the MOA (gray), OGLE (red) and Wise (green) microlensing survey groups along with data from the RoboNET/LCOGT (cyan) and MiNDSTEp (magenta) groups. Also shown is the best-fitting binary lens model light-curve (black line). The epoch when the OGLE collaboration issued an alert for this event is indicated with a black arrow. Data with extremely large errors are omitted. Credit: Nicolas Rattenbury et al., 2016. © 2016 Phys.org , arXiv Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Impostor planet exposed by astronomers Journal information: Monthly Notices of the Royal Astronomical Society (Phys.org)—Using the gravitational microlensing method, an international team of astronomers has recently detected a new gas giant exoplanet three times more massive than Jupiter. The newly discovered planet received designation OGLE-2014-BLG-0676Lb and is an important addition to the short list of extrasolar worlds detected by the microlensing technique. The discovery was described in a paper published Dec. 12 on arXiv.org. Citation: Astronomers discover new gas giant exoplanet (2016, December 14) retrieved 18 August 2019 from https://phys.org/news/2016-12-astronomers-gas-giant-alien-world.html More information: N. J. Rattenbury et al. Faint source star planetary microlensing: the discovery of the cold gas giant planet OGLE-2014-BLG-0676Lb, Monthly Notices of the Royal Astronomical Society (2016). DOI: 10.1093/mnras/stw3185 , On Arxiv: https://arxiv.org/abs/1612.03511AbstractWe report the discovery of a planet —- OGLE-2014-BLG-0676Lb —- via gravitational microlensing. Observations for the lensing event were made by the MOA, OGLE, Wise, RoboNET/LCOGT, MiNDSTEp and μFUN groups. All analyses of the light curve data favour a lens system comprising a planetary mass orbiting a host star. The most favoured binary lens model has a mass ratio between the two lens masses of (4.78±0.13)×10−3. Subject to some important assumptions, a Bayesian probability density analysis suggests the lens system comprises a 3.09+1.02−1.12 M_jup planet orbiting a 0.62+0.20−0.22 M_sun host star at a deprojected orbital separation of 4.40+2.16−1.46 AU. The distance to the lens system is 2.22+0.96−0.83 kpc. Planet OGLE-2014-BLG-0676Lb provides additional data to the growing number of cool planets discovered using gravitational microlensing against which planetary formation theories may be tested. Most of the light in the baseline of this event is expected to come from the lens and thus high-resolution imaging observations could confirm our planetary model interpretation. Unlike other methods of detecting exoplanets, microlensing is most sensitive when it comes to searching for exoworlds that orbit around one to 10 AU away from their host stars. These planets are of special interest for astronomers studying planetary formation theories due to proximity to their parent stars, within the so-called “snow line.” Just beyond this line, the most active planet formation occurs; therefore, understanding the distribution of exoplanets in this region could offer important clues to how planets form.So far, 47 planets have been discovered by microlensing. Currently, several ground-based observation programs routinely monitor dense stellar fields to search for microlensing events. When a new event is discovered, an alert to the broader scientific community is issued in order to allow follow-up observations. Astronomers are particularly interested in events showing evidence for perturbations that could be due to the presence of a planet, or which are predicted to have a high sensitivity to such perturbations.OGLE-2014-BLG-0676, discovered in April 2014 by a Polish astronomical project called the Optical Gravitational Lensing Experiment (OGLE), is one of those interesting microlensing events. Recently, a collaboration of researchers consisting of the OGLE group, the Microlensing Observations in Astrophysics (MOA), the Wise Observatory Group and the Microlensing Network for the Detection of Small Terrestrial Exoplanets (MiNDSTEp), has detected an anomalous signal in this event consistent with a planetary lens system.”The source star passed through the central caustic, with the second caustic crossing being well recorded by the MOA microlensing survey collaboration. Observations at epochs between the unrecorded first caustic crossing and the second caustic crossing were made by the OGLE, Wise and MOA collaborations. (…) All analyses of the light curve data favor a lens system comprising a planetary mass orbiting a host star,” the paper reads.According to the research, the newly discovered planet has a mass of about 3.1 Jupiter masses and orbits its parent star at a deprojected orbital separation of about 4.4 AU. The host star is approximately 38 percent less massive than our sun and was classified as a K-dwarf. The distance to the lens system is about 7,200 light years.Moreover, the team revealed some information about the source star. They revealed that is rather faint and very red, noting that there is a possibility that the source may be blended with a nearby red star, causing an incorrect identification of the source star type.In conclusion, the scientists emphasize the importance of their discovery, noting that OGLE-2014-BLG-0676Lb could serve as a test bed for planet formation scenarios. “Planet OGLE-2014-BLG-0676Lb can be added to the growing list of planets discovered by microlensing against which planetary formation theories can be tested,” the researchers wrote in the paper.
We can state this distinction more directly. eukaryotes run one very specialized version of the electron transport chain while procaryotes run a more generalized system of multiple simultaneously operating electron transport chains. In eukaryotes, it looks something like this:NADH → Complex I → Q → Complex III → cytochrome c → Complex IV → O2 NADH (dehydrogenase) is the electron donor, Complexes I, III and IV are proton pumps, Q is the membrane soluble mobile electron carriers—the quinone pool, and cytochrome c the soluble electron carrierThe prokaryotic chain (bacteria and archaea), on the other hand, includes multiple donors that can input electrons at three levels. Not only are there typically several different initial dehydrogenases used here, there are often different membrane soluble electron carriers that can contribute to the quinone pool, and multiple oxidases and reductases. Borrowing directly from Wikipedia, the generalized schematic looks like this: All schoolchildren learn that the difference between eukaryotes and prokaryotes has something to do with a nucleus. This is usually around the same time they learn that the mitochondria is the powerhouse of the cell. The real difference between these two life forms, however, has more to do with how they control the flow of electrons to make their living, i.e., their electron transport chains going from donors to acceptors via redox reactions. © 2018 Phys.org Although eukaryotes use just one instance of this chain, they have been able to borrow a few tricks from prokaryotes that they can call upon when needed. Under certain circumstances, reverse electron flow can occur at one or more of the respiratory complexes. One thing we left out in the eukaryotic chain above is complex II, which is a branch point that feeds into the Q pool. In a post here on Wednesday, we discussed in some detail how this particular enzyme system (Succinate dehydrogenase) is regulated in the brain by GABA to regulate mitochondrial access to purine nucleotides. Succinate dehydrogenase is also a major stop on the citric acid cycle. When there are local reversals in the direction of the citric acid cycle here, there must also be reverse electron transport at complex II in respiration.Quinones I have known and lovedA recent paper published in eLife describes how and when this occurs in a peculiar protist called pygsuia. The authors discovered that this organism makes a special kind of quinone using an enzyme that it acquired from bacteria by horizontal gene transfer. Pysugia is an anaerobe and it no longer retains full blown mitochondria. Instead, it uses remnant organelles similar to hydrogenosomes. Instead of using coenzyme Q10 (ubiquinone), like humans use in their quinone pool, Pysugia modifies ubiquinone to a molecule called rhodoquinone (RQ) using a specific methyltransferase to replace one methoxy group with an amine. Credit: eLife (2018). DOI: 10.7554/eLife.34292 Credit: Matthew W. Brown et al / Proc. R. Soc. B. doi: 10.1098/rspb.2013.1755 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further Citation: Wisdom of the protists; electron flow tricks for controlling cancer (2018, May 18) retrieved 18 August 2019 from https://phys.org/news/2018-05-wisdom-protists-electron-cancer.html Journal information: eLife The beauty of RQ is that it retains all the structural assets that make ubiquinone so useful—essentials like multiple oxidation states and adjustable length lipid soluble isoprenoid tails for membranes of different thicknesses—but has a reduction potential significantly more negative than ubiquinone (-63 mv vs +100mv). What this means for electron transport is that the reverse reaction at complex II, namely the reduction of fumarate to succinate, becomes much more favorable. When there is no oxygen around (which is normally the terminal electron acceptor used at complex IV), there is little reason for organisms like pysugia to retain any respiratory complexes beyond succinate dehydrogenase. Therefore, they reoxidize RQH2 back to its original RQ form at complex II and generate succinate. Complex I can then cycle again. RQ is not the only alternative to ubiquinone. Bacteria frequently make use of the menaquinone (aka vitamin K2), which is the molecule we utilize for carboxylation of glutamate residues in our coagulation pathway proteins. Plants use phylloquinone (vitamin K1) in photosystem I, and plastoquinone in photosystem II, which has methyl groups in place of ubiquinol’s methoxy groups. Some makers of dubious anti-aging miracle molecules have been known to peddle various plastoquinone-related derivatives. One potential supplement called SkQ1 was specifically designed to penetrate mitochondrial membranes. Another, SkQR1 is a rhodamine-containing analog that has antioxidant and protonophore activity.Many mammalian parasites have a life cycle that requires transit through tissues with widely different oxygen levels in order for them to mature. Some of them, like the ascaris nematode, have managed to get the best of both worlds. They can print off different versions of complex II subunit, along with different Q pool electron carriers, and optimally run reverse electron transport as oxygen levels require. Adult ascaris worms live in low-oxygen intestines and expel their eggs with the feces of their host. When a larva is ingested by a new host, it hatches and invades its intestinal wall, then proceeds to migrate through the host’s organs until it eventually winds up in the lungs, where oxygen alters development. By some hideous magic only a parasite could appreciate, ascaris causes the host to violently cough up the maturing larva, after which they are subsequently swallowed and directed again to the small intestine. Here, they turn off production of complex III and IV, but can continue to make ATP by pumping protons and oxidizing NADH at complex I while recycling RQ at complex II. When organisms like ascaris, or E. coli, or C. elegans maintain dedicated enzymes for running reverse electron transport at complex II, these enzymes are called fumarate reductases as opposed to succinate dehydrogenases.If you need to kill any such parasite lurking within you, this can be a special thing. Researchers have uncovered compounds, like nafuredin, that specifically inhibit the NADH dehydrogenase complex in the mitochondria of helminths. Similarly, atpenin and flutolanil inhibit complex II at its quinone binding site. To appreciate why we said ‘controlling cancer’ in the headline, we need to open one final gift from science: Many human cancers can thrive in poorly vascularized centers of tumors or other low-oxygen pockets in the body. Of particular note, fumarate respiration has been observed in many kinds of cancer.Ascaris makes different varieties of each of Complex II’s four subunits; a flavoprotein subunit (Fp), iron–sulfur subunit (Ip), cytochrome b large subunit (CybL), and cytochrome b small subunit (CybS). Humans don’t have special RQ quinones, nor do they keep any bonafide fumarate reductase enzymes on tap. However, they do have two separate versions of the Fp subunit, and produce them both in most tissues. Researchers have found that many cancers including breast, lung and lymphoma preferentially make the type II Fp subunit.Genetic sequencing has revealed that several varieties of tumors, like pheochromocytoma and paraganglioma, are associated wth certain variants of complex II genes. These tumors are also associated with specific assembly factors that help construct and position complex II. Complex II is unique in that all its subunits are encoded in the nucleus. There is still some debate about where and how many complex II units get coordinated into larger respiratory supercomplexesthat can confine the Q and cytochrome C mobile electron carriers. It is now understood that the translation and early assembly of complex III and complex IV occur at the inner membrane boundary while that of complex V takes place deep in the cristae.Today, many new therapies depend on which particular variants you and your tumor happen to have. Before antihelminthic compounds become a standard of care tumor treatments, there are several other important enzyme systems that deal in quinones that may need to be fully investigated. For example, these include quinone biosynthesis enzymes, alternative oxidase, glycerol-3-phosphate dehydrogenase, and dihydroorotate dehydrogenase (DHODH).DHODH is a critical step in de novo pyrimidine biosynthesis and requires complex III to regenerate ubiquinone in order to function. Appreciating these many subtle links between electron transport and synthesis of the fundamental building blocks of life is critical to understanding what cancer is. More information: Courtney W Stairs et al. Microbial eukaryotes have adapted to hypoxia by horizontal acquisitions of a gene involved in rhodoquinone biosynthesis, eLife (2018). DOI: 10.7554/eLife.34292 Photosynthesis involves a protein “piston”
Three dimly-lit floors and a nicely-done up terrace. The Pink Room impresses you with the decor when you walk in. Wooden chests that double up as tables, comfortable sofas and chairs, quirky posters and lyrics of songs and framed photographs of musicians — this newly-opened place in Hauz Khas Village is your typical after-work den. With music in the background, a bar that serves regular alcohol (nothing too fancy mind you, except the Grey Goose) and some pretty chilled out spaces are things that work in favour of this restaurant. Going by the name, one would expect that everything would be overtly pink and therefore either very garish or very girly. Thankfully, the owners have ensured that one disaster is avoided. The colour pink is present here, though very subtly. Also Read – ‘Playing Jojo was emotionally exhausting’The menu is all that’s popular now in the youth circuit — Thai, Italian and Mediterranean, with bits of Punjabi and includes a breakfast selection. The beverage menu is average and there is a lot of scope of improvement, especially in the cocktail section which is average. Also, the staff need training in the serving of alcohol with the right amount of accompaniments like ice and soda. often, too much water or molten ice spoilt the drink when I went there. Also Read – Leslie doing new comedy special with NetflixThe food again, is mostly average with the exception of some fantastically cooked dishes. Worth a mention is the Lamb Tajine with cous cous prepared with some very fresh and soft lamb. Skip the risotto even if you are fond of it. Another item I liked was the Roasted chicken pesto pizza with extra cheese. Thin crust and really nice. Overall, go to The Pink Room for the ambience, if not so much for the food.DETAILAt: 29 A, Hauz Khas VillageTimings: Noon to midnightPhone: 30146122 Meal for Two: Rs 2,100
Kolkata: One person was killed and as many as 23 people were injured in several road accidents in the state since Tuesday night. Around 20 passengers travelling in two private buses were among the injured as one bus rammed into another on Jessore road in Birati.In the first incident, a middle-aged man was killed after being hit by a speeding vehicle while he was trying to cross the road in North port police station area. When the victim fell on the road, he was crushed under the wheels. The truck driver fled the spot along with the vehicle after the accident. The victim died on the spot. Also Read – Rain batters Kolkata, cripples normal lifeAfter being informed, police reached the spot and sent the body for the post -mortem. Locals staged a demonstration in the area alleging poor condition of the road. They also alleged that there are no proper street lights in the area. The vehicles often over speed resulting in road accidents.The matter was raised with the local police administration but no steps were taken in this regard. Senior police officers later pacified the mob and gave them assurances that surveillance would be carried out in the area to control the speed of the vehicles. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedIn a separate incident, around 20 persons,who were travelling in two private buses, were injured after one bus hit the other on Jessore road near Birati More on Wednesday afternoon. The incident caused traffic congestion on the busy Jessore road.According to locals, the incident occurred when a private bus of DN 8 route was competing with another private bus of L238 route to pick up extra passengers.Both the vehicles were running at high speed when the bus of DN 8 route hit the L238 from behind. Around 20 passengers travelling in both the vehicles were injured in the incident. Many other passengers were traumatized following the incident. Both the buses were going to Barasat. Locals took part in the rescue operation and rushed the injured passengers to a nearby municipality hospital. Police later reached the spot and seized the vehicles. A probe has been initiated in this regard.Three persons were injured in two separate accidents in New Town. One incident took place near Eco Park gate number 6 at around 8 am on Wednesday.A woman, identified as Feroza Bibi, was injured after being hit by a Tata Sumo.She was taken to RG Kar Medical College and Hospital. In the other incident, two private cars collided near Biswa Bangla Convention Centre injuring two persons.Police seized both the vehicles and started a probe.