Square array created with the laser burn-out method, with a close-up. Credit: Wei Hsuan Hung, et al. The researchers grew the MWNTs in a tube furnace heated to 650 degrees Celsius. Then they focused a high-powered 532-nm laser through a microscope onto the densely packed vertical nanotubes, burning some of the nanotubes to create the desired pattern. Burnout occurred in less than a second at an estimated temperature of around 800 degrees Celsius in air. The researchers found that burnout required a minimum laser power of 244 microwatts, and they tested the method with laser powers up to 9,000 microwatts.“The initial burnout we observed came as quite a surprise and appeared very striking in our microscope images,” Cronin said. “Typically, carbon nanotubes lying on a silicon wafer are very difficult to heat with a laser.”Until now, most attempts at patterning microstructures have been done with conventional lithography or other techniques. However, lithography is limited to 2D structures and leaves chemical residues that would be incompatible with biological applications. Other methods don’t use nanotubes as the medium, and so cannot take advantage of nanotubes’ desirable properties, such as mechanical strength, high surface area, and electrical and thermal conductivities.Laser burnout seems to offer a good solution, as it’s quick, doesn’t involve chemicals, and the resolution is limited primarily by the spot size of the objective lens. Using Raman spectroscopy, a non-contact method for measuring the wavelength and intensity of scattered light, the researchers could determine the depth of the burn. This testing revealed that burnout depth increased with laser power, and the minimum burnout depth was 5 micrometers, which could be decreased further with the use of a higher numerical aperture microscope lens. 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. Cylindrical pattern created with the laser burn-out method, with a close-up. Credit: Wei Hsuan Hung, et al. Using a focused laser beam to selectively burn regions of a dense forest of multiwalled carbon nanotubes (MWNTs), researchers have demonstrated a method that may enable rapid prototyping of nanotube microstructures. The researchers, from the University of Southern California and NASA’s Jet Propulsion Laboratory, have published their results in a recent issue of Applied Physics Letters. They fabricated patterns in the nanotubes such as a staircase structure, cylindrical structures, and square arrays with the laser burning method, which might be used for creating gas and liquid transport channels for various applications.“While carbon nanotubes possess many exceptional properties which far exceed most known bulk materials, creating controlled nanotube structures has always been a challenge,” co-author Stephen Cronin told PhysOrg.com. “By overcoming this challenge, our technique enables chemically sensitive fields to take advantage of nanotubes’ exceptional properties and expand their possible applications into new areas.” Citation: Scientists carve 3D microstructures in carbon nanotube forests (2007, September 14) retrieved 18 August 2019 from https://phys.org/news/2007-09-scientists-3d-microstructures-carbon-nanotube.html The researchers also noticed an interesting phenomenon that occurred after laser treatment, which was the development of white spots ranging in size from 100 to 200 nm on the top of the MWNT forests. A scanning electron microscope revealed that the white spots were nanotube bundles that aggregate during the burnout process, providing some insight into the dynamics of the process.The researchers hope to use the technique to create well-defined gas and liquid transport channels as well as deep trenches for superhydrophobic microfluidic channels. The checker board-like arrays may also be suitable for field emission applications. Further, the researchers suggest that the method may serve as a basis for developing similar patterning methods in other material systems.“Potential applications are on-chip DNA manipulation, chemical and protein identification, templates for directed stem cell growth, and gas mixture separation,” said Cronin.Citation: Hung, Wei Hsuan, Kumar, Rajay, Bushmaker, Adam, Cronin, Stephen B., and Bronikowski, Michael J. “Rapid prototyping of three-dimensional microstructures from multiwalled carbon nanotubes.” Applied Physics Letters 91, 093121 (2007).Copyright 2007 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.
Polymer laser. Image credit: Organic Semiconductor Optoelectronics / University of St Andrews 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. (PhysOrg.com) — Detecting hidden explosives is a difficult task but now researchers in the UK have developed a completely new way of detecting them, with a laser sensor capable of detecting molecules of explosives at concentrations of 10 parts per billion (ppb) or less. © 2010 PhysOrg.com New method for detecting explosives More information: Ying Yang et al., Sensitive Explosive Vapor Detection with Polyfluorene Lasers, Advanced Functional Materials, Published Online: 25 May 2010. DOI:10.1002/adfm.200901904 Explore further The laser sensor, developed by physicists from the University of St Andrews in Fife, Scotland, relies on the fact that when a type of plastic called polyfluorene is “pumped” with photons of light from a light source it emits laser light. When molecules of the vapors emitted by explosives such as TNT are present, they interfere with the laser light, switching off the emission, and the interference can be measured.One of the scientists, Dr. Graham Turnbull, explained that there is a dilute, weak cloud of vapors of nitroaromatic-based explosive molecules above an explosive device. He said the laser could be thought of as an “artificial nose for a robot dog.”In the study a plastic laser was exposed to 1,4-dinitribenzene (DNB) vapors at 9.8 ppb concentration. The light emitted by the laser decreased rapidly, allowing for detection within seconds of the exposure. After 4-5 minutes the response had slowed and then flattened off, which the researchers suggest is due to the vapor molecules interacting with the surface of the polyfluorene. The laser took three and a half hours to recover in air, but only three minutes if nitrogen gas was flushed through it and 20 seconds if purged under a vacuum.The plastic polyfluorene is a cheap material, which is an obvious advantage for a device designed to detect explosives. Dr. Turnbull said that while similar techniques using organic semiconductor lasers had been looked at before, this is the first time scientists have used a polyfluorene laser, and its use enables much lower concentrations of vapors to be detected. Organic semiconductor lasers detect explosive vapors because of a chemical interaction between the vapor and the semiconductor in which electrons are transferred from the semiconductor to the electron-deficient vapor molecules. It is this transfer of electrons that reduces the light emitted by the laser. The same electron-transfer effect occurs with the new polyfluorene laser.The drawback with the laser sensors is that the explosives must be in the very near vicinity, which limits its use for humans, but they could prove extremely useful for applications such as roadside bomb detection in Iraq and Afghanistan, for security checkpoints, luggage screening in airports, and for bomb disposal robots generally. The system could also be used in conjunction with remotely controlled robots for detecting land mines, which are still a danger to people in areas such as Southeast Asia.The findings were published in the journal Advanced Functional Materials. Citation: Plastic laser detects tiny amounts of explosives (2010, June 8) retrieved 18 August 2019 from https://phys.org/news/2010-06-plastic-laser-tiny-amounts-explosives.html
Similar to how electrons orbit an atomic nucleus without collapsing inward, mini black holes below a certain mass may cause surrounding matter to orbit without falling into the black hole. Image credit: Halfdan, Wikimedia Commons. More information: A. P. VanDevender and J. Pace VanDevender. “Structure and Mass Absorption of Hypothetical Terrestrial Black Holes.” arXiv:1105.0265v1 [gr-qc] (PhysOrg.com) — In a new study, scientists have proposed that mini black holes may interact with matter very differently than previously thought. If the proposal is correct, it would mean that the time it would take for a mini black hole to swallow the Earth would be many orders of magnitude longer than the age of the Universe. Explore further What are ‘mini’ black holes? Citation: Mini black holes that look like atoms could pass through Earth daily (2011, May 13) retrieved 18 August 2019 from https://phys.org/news/2011-05-mini-black-holes-atoms-earth.html 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. Although this may seem purely theoretical, the concept could provide a way to test the current theory of how mini black holes age and die, called quantum evaporation. In this process, mini black holes lose mass until they eventually disappear. As they lose mass, they should produce X-rays. However, attempts to observe the X-ray signature of the final stages of evaporation have so far been unsuccessful. This lack of evidence suggests that either mini black holes were not created in large numbers as predicted, or that they do not evaporate.Assuming the latter explanation, the VanDevenders propose that, instead of searching only for evaporation effects, researchers should search for evidence of the actual existence of the mini black holes, as well. If their theory of mini black holes as GEAs is correct, then the gravitationally bound matter in a GEA should produce emissions that could be detected with current detectors, even though the chance of detecting these emissions would be slim.“Quantum evaporation has been a major cornerstone of quantum gravity theories for three decades, yet it has never been experimentally confirmed,” Aaron VanDevender told PhysOrg.com. “Our study asks, ‘what if small back holes do not evaporate?’ We have shown that if they do not evaporate, they may interact with matter and be detected. If we are able to observe such objects, it will have a significant impact on our understanding of black hole evaporation, and quantum gravity in general.”How a GEA worksIn their paper, the researchers mathematically describe how a black hole can exist on Earth without consuming all of the surrounding mass. Such a mini black hole has constraints on its Schwarzschild radius, which is the closest an object can be to a black hole before it is absorbed, never to escape. Any object smaller than its Schwarzschild radius is a black hole. But because mini black holes with masses below 1012 kg are so small, they can have a Schwarzschild radius that is much smaller than the orbit of the gravitationally bound matter particles. As long as these matter particles stay beyond the mini black hole’s Schwarzschild radius, they will orbit rather than be absorbed. (Black holes with masses of 1012 kg have a Schwarzschild radius that equals the ground state radius at which the nearest matter particles orbit, so this mass is the upper limit for a GEA.) The researchers compare the GEA’s risk of collapse with that of real atoms.“The concern that a terrestrial GEA might absorb the earth is similar to the early 20th century expectation that electrons orbiting a nucleus should radiate their energy away and fall into the nucleus,” the researchers wrote in their study. “Since the electron energy levels are quantized and the expectation value of the radius of the ground state is much larger than the radius of the nucleus, the probability of an electron being captured by the nucleus is vanishingly small. Similarly, particles of mass m are unlikely to fall into the black hole at the center of a GEA; however, those few that do could, in principle, provide energy for observable emissions.”Up closeThe scientists calculated that mini black holes with a mass of about 100,000 kg may be of particular interest, since they could be candidates for dark matter. They estimated that, if dark matter is composed primarily of mini black holes and is evenly distributed throughout the galaxy, then about 40 million kg of mini black holes should pass through the Earth every year. The researchers calculated that about 400 mini black holes per year could be detectable through their strong electromagnetic emissions from their gravitationally bound matter.If a particle on Earth approaches a GEA while it’s passing through the planet, the particle could either scatter off, be captured in orbit, or strip an already bound particle off. Due to the mini black hole’s high velocity compared to the binding energy required to capture a particle, the researchers predict that the mini black hole would quickly be stripped of its particles as it passes through the Earth. Therefore, the search for the emissions should be focused on space-based sources. “It would be difficult, but not impossible [to detect one of the mini black holes passing through the Earth],” Aaron VanDevender said. “The available power of a GEA to emit detectable radiation is small but not negligible. It would likely be substantially easier to observe a GEA in orbit around the Earth, rather than one that is passing through at a tremendous velocity. Also, the larger GEA will likely be much easier to detect, so it is worth focusing our observational efforts on objects in the range of 104 to 106 kg.”The researchers also noted that black holes created at the LHC would be too small and not have sufficient binding energy to bind matter into quantum orbitals that might emit detectable radiation.In any case, according to this theory, mini black holes of any size would not absorb large amounts of matter very quickly. The scientists calculated that, for a black hole with a mass of 1 kg, it would take 1033 years to swallow the Earth. For comparison, the Universe is about 13.7 x 109 years old. And for smaller black holes like those that might be formed at the LHC, the time it would take to absorb the Earth would be even longer. © 2010 PhysOrg.com In their paper, which is posted at arXiv.org, Aaron P. VanDevender from Halcyon Molecular in Redwood City, California, and J. Pace VanDevender from Sandia National Laboratories in Albuquerque, New Mexico, wanted to find a way to detect the mini black holes that are thought to exist in nature. Their calculations suggest that mini black holes may be passing through the Earth on a daily basis, and pose a very minimal threat to the planet.Orbiting matterMini black holes are different than the ordinary astrophysical black hole in terms of how they’re formed and their size. Whereas astrophysical black holes are formed by the collapse of giant stars, mini black holes are thought to have formed during the Big Bang, which is why they’re also called primordial black holes. And while an astrophysical black hole has a minimum mass of 1030 kg, the mass of mini black holes range from the tiny Planck mass to trillions of kilograms or more, but are still much smaller than astrophysical black holes. (Although physics should allow for black holes of all sizes, scientists don’t yet know of any mechanism that could produce objects in the intermediate range.) The expected mass of laboratory-produced mini black holes is on the small side, about 10-23 kg. Because of their extreme density, even the most massive mini black hole is microscopic in size. The conventional view of a black hole is one of an object that is so dense that its powerful gravity pulls in all nearby matter past a critical point called the event horizon, from where it cannot escape. But the VanDevenders have suggested that something different happens with mini black holes with masses below 1012 kg. Instead of absorbing matter, these mini black holes may gravitationally bind matter, so that matter orbits the black holes at a certain distance. Because matter atoms orbiting a black hole due to gravity are reminiscent of the way that electrons orbit a nucleus due to electrostatic forces – both without collapsing inward – the physicists call this theoretical system the Gravitational Equivalent of an Atom (GEA).
The trouble with earthquakes, other than their obvious devastation, is that thus far they have proved to be very nearly impossible to predict, despite considerable effort towards that goal; being able to do so would obviously save a lot of lives. Also, despite the fact that there is literally hundreds, if not thousands of years of anecdotal evidence suggesting that some animals may have some innate ability to predict quakes, modern research has instead been steadfastly focused on studying the Earth, rocks, faults, etc. Toads’ earthquake exodus More information: Int. J. Environ. Res. Public Health 2011, 8, 1936-1956; doi:10.3390/ijerph8061936 That may change now that biologist Rachel Grant, from the UK’s Open University has found evidence that toads can predict a quake up to several days before the ground starts shaking. She’s teamed up with NASA geophysicst, Friedemann Freund and the two of them, as they describe in their paper in the Journal of Environmental Research and Public Health, suggest that it might all be because of changes to the pond water in which the toads are living.Grant was studying the toads that lived in a pond near L’Aquila, Italy, in 2009 in the days just before a devastating earthquake struck. In those few days just before it happened, she noted that the toads began leaving. Their numbers dwindled from just under a hundred, to zero, causing her to write about her observations in the Journal of Zoology. That caught the attention of Freund, who was doing work for NASA in studying what happens to rocks when put under extreme stress, as in say, when an earthquake is in the making. He contacted Grant, and the two of them began investigating ways that such rock pressure could impact the environment where the toads lived.After some experiments in the lab, the two write that when rocks underground come under pressure as a result of geological processes, they let off charged particles. Such particles can very quickly rise to and above the surface of the Earth, impacting such things as pond water and the biological material in it. In the case of the pond in Italy, it seems the toads may have been reacting to changes they felt in the water itself as ions interacting with it react to form minute amounts of hydrogen peroxide. Or it seems possible that ions interacting with organic material in the pond caused substances to be released that either were toxic or less ominously, simply irritating. Either way, it would explain their sudden exodus.The problem with proving their theory though, is of course, they’d have to know when and where an earthquake is about to strike so as to allow them to set up testing equipment in advance. Perhaps the best that can be done at this point, is for such information to disseminated all over the world, so that if anyone happens to live near a pond, and notices that the toads are leaving, they would be wise to follow them. Explore further © 2011 PhysOrg.com Citation: New study suggests how toads might predict earthquakes (2011, December 2) retrieved 18 August 2019 from https://phys.org/news/2011-12-toads-earthquakes.html 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.
(PhysOrg.com) — Way back in the 1930’s, Albert Einstein and Niels Bohr were sparring over ideas related to whether the new field of quantum mechanics was correct. In one thought experiment that Einstein said showed that quantum mechanics was inconsistent, he said the Heisenberg principal could be shown to be inconsistent by imagining a box of photons that could be measured both time-wise and energy-wise at the same time. Bohr knocked down Einstein’s arguments and in the process elevated his stature among their peers. Now, however, Hrvoje Nikoli at the Rudjer Boskovic Institute in Croatia says that Einstein could have won that argument had he used the argument he gave Bohr just five years later in trying to explain how entanglement made quantum mechanics inconsistent. Nikoli has published his reasoning on the preprint server arXiv. © 2011 PhysOrg.com New light shed on old dispute between Einstein and Bohr Explore further In the first thought experiment presented by Einstein, he proposed that if the lid were opened on a box full of photons allowing just one to escape, it could be measured time-wise by simply measuring how long the box was open. He then said it could be simultaneously measured energy-wise by measuring the change in the total amount of energy in the box. This he said disproved the Heisenberg principle which meant quantum mechanics was inconsistent. After some thought, Bohr replied that if Einstein’s own theory of relativity were brought into the experiment, the apparent inconsistency could be explained away by noting that the measurement took place in a gravitational field, thus, the measurement of the time that the lid was open on the box would depend on it’s position. Einstein was unable to counter Bohr’s argument and lost that round.Five years later, the two were at it again. This time Einstein said that there was no way quantum mechanics could include both entanglement and the belief that nothing could travel faster than the speed of light. If causing a change to one particle instantly caused a change in the other, how could it do so without violating such a basic principle? He called the whole thing “spooky action at a distance.” Bohr was unable to come up with a reasonable argument in response. And neither has anyone else for that matter, though John Bell made it more palatable in 1964 by declaring entanglement a wholly new kind of phenomenon, which he dubbed “nonlocal.”This is where Nikoli comes in. He says that had Einstein put forth his arguments regarding entanglement five years earlier during their debate about the Heisenberg principle, he could have won by suggesting that the photon escaping from the box was entangled with the box itself, thus quashing any possible response from Bohr. But alas, that was not to be, Einstein didn’t think of that and thus, Bohr went on to win that first round, one of just a few such occurrences in Einstein’s illustrious career. More information: EPR before EPR: a 1930 Einstein-Bohr thought experiment revisited, arXiv:1203.1139v1 [quant-ph] arxiv.org/abs/1203.1139In 1930 Einstein argued against consistency of the time-energy uncertainty relation by discussing a thought experiment involving a measurement of mass of the box which emitted a photon. Bohr seemingly triumphed over Einstein by arguing that the Einstein’s own general theory of relativity saves the consistency of quantum mechanics. We revisit this thought experiment from a modern point of view and find that neither Einstein nor Bohr was right. Instead, this thought experiment should be thought of as an early example of a system demonstrating nonlocal “EPR” quantum correlations, five years before the famous Einstein-Podolsky-Rosen paper.via Arxiv Blog Citation: Physicist suggests Einstein could have beaten Bohr in famous thought experiment (2012, March 9) retrieved 18 August 2019 from https://phys.org/news/2012-03-physicist-einstein-beaten-bohr-famous.html 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.
© 2016 Phys.org More information: Claudio Maggi, et al. “Self-Assembly of Micromachining Systems Powered by Janus Micromotors.” Small. DOI: 10.1002/smll.201502391 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 The researchers, Claudio Maggi, et al., from Italy, Germany, and Spain, have published a paper on the microgears in a recent issue of the journal Small.”The modern tools of nanotechnology can be used to shape matter at the micron and nanoscale with a high degree of structural and morphological control,” Maggi, at the University of Rome, told Phys.org. “Recently researchers have started to investigate possible strategies to ‘give life’ to these structures and provide them with some mechanism for self-propulsion. The whole effort of miniaturizing machines becomes useless, however, if large and expensive equipment is still required to drive and control propulsion at the micron scale. For this reason, we are working on the development of advanced materials, collectively referred to as ‘active matter,’ that can convert some embedded energy source into directed motion.”The active matter materials used here are micromotors in the form of Janus particles. Like the two-faced Roman god, Janus particles have two faces, or surfaces, that give them an asymmetric character. Here, one side of each 5-µm particle is coated with platinum, so that when the particles are immersed in a hydrogen peroxide solution, they move in one direction. In a solution containing both Janus particles and passive 8-µm microgears, some of the self-propelled Janus particles collide with the microgears. The Janus particles then autonomously orient themselves so that their propelling direction runs along the sides of the gears, and their forward momentum locks them in place in the gears’ teeth. Up to six Janus particles can be lodged into the microgears’ six teeth.This strategy is similar to previous methods of moving microobjects that use the collective motion of bacteria or synthetic microswimmers. However, all of these previous methods have required high bacteria/microswimmer concentrations and moved in a highly random way, making it difficult to control and reproduce the motion. The biggest advantages of the new method are that it works with lower particle concentrations and the motion is highly deterministic. The researchers found that the microgear’s spinning speed increases linearly as the number of Janus particles locked into the gear increases from 1 to 3. With 4 particles and beyond, the speed flattens out and then begins to decrease, which is likely because the additional Janus particles deplete the hydrogen peroxide fuel so that the speed of all the particles decreases.”We have now demonstrated that active Janus colloids can self-assemble around a micro-fabricated rotor in reproducible configurations with a high degree of spatial and orientational order,” said coauthor Roberto Di Leonardo at the Italian National Research Council, and the coordinator of the research group. “The interplay between geometry and dynamical behavior leads to the self-assembly of autonomous micromotors starting from randomly distributed particles. Besides having a clear technological interest, our results demonstrate that understanding fundamental aspects of interactions in active matter systems opens the way to highly reproducible and controllable micromachines for lab-on-chip applications.”In the future, the researchers plan to investigate how tuning the concentration of hydrogen peroxide can be used to control the rotational speed of the micromotors. Controlling the speed is essential for lab-on-chip micromachines and other applications.The research was funded by two ERC Starting Grants and combines recent advances in catalytic propulsion (Grant n. 311529) and statistical mechanics of active matter (Grant n. 307940). Janus particles dock in between the teeth of a microgear to propel it forward. Credit: Maggi, et al. ©2015 Small Journal Micromotors for energy generation Citation: Microgears rotate when pushed by tiny motors (2016, January 11) retrieved 18 August 2019 from https://phys.org/news/2016-01-microgears-rotate-tiny-motors.html Journal information: Small (Phys.org)—Researchers have designed a new type of microgear that spins when micromotors become lodged into the corners of the gear’s teeth. The micromotors use the surrounding hydrogen peroxide solution as fuel to propel themselves forward, which in turn causes the microgears to spin. In the future, the tiny gears could be used as the building blocks for making autonomous micromachines.
© 2016 Phys.org 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. Sorghum. Credit: Public Domain A model of the dhurrin metabolon, summarizing results presented in the paper. Credit:Jean-Etienne Bassard Play 3D model reconstructed from confocal microscope images, using CYP71E1-eGFP as a mean to observe the structures of the Endoplasmic Reticulum. The Endoplasmic Reticulum is where the dhurrin metabolon forms. Only a part of one cell is visible. Credit: Jean-Etienne Bassard PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen (Phys.org)—An international team of researchers has uncovered the mechanism by which the sorghum plant uses the compound dhurrin to ward off pests and herbivores. In their paper published in the journal Science, the team describes their study, their results and the possible impact of their findings on the field of metabolon research. Mehran Dastmalchi and Peter Facchini with the University of Calgary offer a perspective piece on the work done by the team in the same journal issue, calling it a “watershed in metabolon research.” Explore further More information: T. Laursen et al. Characterization of a dynamic metabolon producing the defense compound dhurrin in sorghum, Science (2016). DOI: 10.1126/science.aag2347AbstractMetabolic highways may be orchestrated by the assembly of sequential enzymes into protein complexes, or metabolons, to facilitate efficient channeling of intermediates and to prevent undesired metabolic cross-talk while maintaining metabolic flexibility. Here we report the isolation of the dynamic metabolon that catalyzes the formation of the cyanogenic glucoside dhurrin, a defense compound produced in sorghum plants. The metabolon was reconstituted in liposomes, which demonstrated the importance of membrane surface charge and the presence of the glucosyltransferase for metabolic channeling. We used in planta fluorescence lifetime imaging microscopy and fluorescence correlation spectroscopy to study functional and structural characteristics of the metabolon. Understanding the regulation of biosynthetic metabolons offers opportunities to optimize synthetic biology approaches for efficient production of high-value products in heterologous hosts. Journal information: Science Prior research has found that the sorghum plant releases chemicals in response to attacks by plant eaters or pests—one such chemical, a substance called hdurrin, has been found to turn into cyanide when hydrolyzed. It is classified as one of a type of complexes known as metabolons, which are temporary complexes formed between enzymes in a metabolic pathway. They maintain their structure due to interactions between cell structures and membrane proteins present in the cytoskeleton. Unfortunately, the nature of metabolons is still not very well understood. In this new effort, the researchers sought to learn more about the general nature of such complexes by studying what happens when sorghum plants are attacked.The team used a recently developed technique that involved the use of styrene maleic acid copolymer and affinity chromatography to obtain lipids along the endoplasmic reticulum which allowed them to isolate dhurrin samples. This allowed them to identify four of the players involved in converting an amino acid to dhurrin. One of them, they found, was a protein that served as an electron donor; two others were proteins that triggered the process, and the fourth was an enzyme that helped the other transactions take place. All four proteins performed in concert, they noted, to convert an amino acid called L-tyrosine to dhurrin. They also found that the membrane itself was actually a critical part of the metabolon character. New forage plant prepares farmers for climate changes Dastmalchi and Facchini note that in addition to offering new insights into how dhurrin is converted to cyanide, the team perhaps more importantly revealed the major role that the endoplasmic reticulum plays in the process and in the workings of metabolons in general. Citation: Characteristics of a metabolon producing the defense compound dhurrin in sorghum revealed (2016, November 18) retrieved 18 August 2019 from https://phys.org/news/2016-11-characteristics-metabolon-defense-compound-dhurrin.html
A depiction of the double helical structure of DNA. Its four coding units (A, T, C, G) are color-coded in pink, orange, purple and yellow. Credit: NHGRI © 2018 Phys.org Citation: Should the police be allowed to use genetic information in public databases to track down criminals? (2018, June 8) retrieved 18 August 2019 from https://phys.org/news/2018-06-police-genetic-databases-track-criminals.html 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. How cops used a public genealogy database in the Golden State Killer case Journal information: Science A trio of concerned citizens from the University of Baltimore and Baylor College of Medicine has published a Policy Forum piece in the journal Science surrounding the issue of law enforcement using genetic information in public databases to pursue criminals. In their paper, Natalie Ram, Christi Guerrini and Amy McGuire highlight the issues involved and offer some suggestions regarding how the issue might best be handled. More information: Natalie Ram et al. Genealogy databases and the future of criminal investigation, Science (2018). DOI: 10.1126/science.aau1083SummaryThe 24 April 2018 arrest of Joseph James DeAngelo as the alleged Golden State Killer, suspected of more than a dozen murders and 50 rapes in California, has raised serious societal questions related to personal privacy. The break in the case came when investigators compared DNA recovered from victims and crime scenes to other DNA profiles searchable in a free genealogical database called GEDmatch. This presents a different situation from the analysis of DNA of individuals arrested or convicted of certain crimes, which has been collected in the U.S. National DNA Index System (NDIS) for forensic purposes since 1989. The search of a nonforensic database for law enforcement purposes has caught public attention, with many wondering how common such searches are, whether they are legal, and what consumers can do to protect themselves and their families from prying police eyes. Investigators are already rushing to make similar searches of GEDmatch in other cases, making ethical and legal inquiry into such use urgent. Explore further The case of police arresting a man suspected of being the Golden State Killer made headlines recently, partly because of the notoriety of the case and partly because of the way the case was cracked. The police compared DNA samples taken from crime scenes with those in a public database and found a close match—someone who was related to the suspect. Further work allowed them to narrow their search down to the man who was arrested. While most people likely received the news of a serial killer’s capture as good news, others were also concerned about how it happened. This led to questions about the privacy of data in public databases—such as whether the police should be allowed to use such data to search for a suspect.The authors point out that there is no law forbidding what the police did—the genetic profiles came from people who willingly and of their own accord gave up their DNA data. But should there be? If you send a swab to Ancestry.com, for example, should the genetic profile they create be off-limits to anyone but you and them? It is doubtful that many who take such actions fully consider the ways in which their profile might be used. Most such companies routinely sell their data to pharmaceutical companies or others looking to use the data to make a profit, for example. Should they also be compelled to give up such data due to a court order? The authors suggest that if the public wants their DNA information to remain private, they need to contact their representatives and demand that legislation that lays out specific rules for data housed in public databases.
Seeing the world in a grain of sand, capturing the gist of life in a blob of paint — can a canvas capture that? Can devotion, in a land chockfull of contradictions and numerous religious thoughts , be perceived as an abstract and metaphysical piece of creative contemplation, essentially secular and spiritual work of art? The pensive and meditative portraits of spiritual gurus and godly figures of Buddha, Krishna, Shiva, Parvati and others by artists Satish Gupta, Shuvaprasanna, Sudip Roy, Puja Bahri, Prithvi Soni, Chottu Lal ,amongst others, exemplify just that beautiful tenet of Indian spiritual philosophies. Also Read – ‘Playing Jojo was emotionally exhausting’Evocative of complete surrender to the idol of their devotion, the artists dig into their inner selves to seek solace and a relief from the transient nature of life and the ephemeral world around, goading one towards a spiritual path of humility. There is a philosophical and mystical sophistication in their work as well as Sidharth’s art who paints using his hand made colors. The line between the sacred and the profane comes into full play in Sanjay Bhattacharya’s drawings in Pen, ink and water colors. Also Read – Leslie doing new comedy special with NetflixDevotion transforms into adulation and obsession as search for human and physical love, be it a man for a woman or mother for her child. It comes to the fore as in the courting couples and other figurative compositions in paintings by Asit Patnaik, Nayana Kanodia , Mousumi Biswas and Shipra Bhattacharya. The seeds of devotion planted in the mind by desire or awe blossom into love or respect for the chosen subject that often transforms individuals and their life. Depending on its intensity and echelon, ranging from adulation to obsession for a particular entity, cause, idea or faith, human or saintly, factual or fictional, its pursuit can turn things around into one of the two extreme modes of renunciation or revulsion. Then there are fluid depictions at cross roads between painting and sculpture by Venkat Bothsa. Evoking the flourish of the street painter, images of the lotus with the curling tendrils play themselves in painted steel in large dramatic sizes. The cryptic written word found often on the rear of public vehicles has communicated directions, slogans and sometimes nothing. The fonts were developed in an indigenous flavor, combining popular culture, street graffiti and a homegrown language. This is what Alex Davis looks into Devotion. The folk element continues to play through colorful paintings of Telangana women by Vaikuntam.Nature appears in a different mode and frame in Surya Prakash’s colourful landscape and Gurdeep Singh’s bright and colorful canvases. The changing life patterns and the world around are seen to get differently moulded in metal sculptures by Dimpy Menon, Gautam Bhatia and Enas MJ.
The five day celebration of classical music in the Capital came to an end with a spellbinding jugalbandi between two maestros Pt Shiv Kumar Sharma and Pt Hari Prasad Chaurasia on Saturday. The two classical music doyens came together for the music lovers in the national capital at Siri Fort Auditorium. The final day of the festival was characterised by the best of classical music, a full house and a lot of excitement to match up to it, as the veteran santoor maestro and the legendary flautist performed together. Also Read – ‘Playing Jojo was emotionally exhausting’The five day celebration was marked by the best of classical music presented by veteran vocalists, sitar, sarod, santoor, flute and veena players. The performances by some of India’s most celebrated classical music artists lit up the Capital and attracted the lovers of the classical music tradition. Capital witnessed legends like Pandit Jasraj, Ustad Mashkoor Ali Khan, Vidushi Girija Devi, Meeta Pandit and Manjari Asnare. Vocalists were supported by renowned artists like Veena player Ustad Mustafa Raza; sitar maestro Budhaditya Mukherjee, sarod maestro Pt. Biswajit Roy Chowdhury, santoor maestro Pt. Shiv Kumar Sharma and renowned flautist Pt. Hariprasad Chaurasia. Also Read – Leslie doing new comedy special with NetflixThe festival was presented by Delhi Government’s Department of Art, Culture and Languages along with the Punjabi Academy under the theme Delhi Celebrates. Each day at Delhi Classical Music Festival was undoubtedly one of its kind. ‘As part of Delhi Celebrates we make sure that art and culture get its due spot in the national capital. Our country’s rich and soulful classical music traditions have gifted us with a culturally-rich identity. This week-long festival aims to promote the best of Indian classical music amongst music lovers,’ said Rawail Singh, Secretary, Punjabi Acacdemy.