Citation: Physicists Investigate Controversy over Room-Temperature Ice (2008, August 5) retrieved 18 August 2019 from https://phys.org/news/2008-08-physicists-controversy-room-temperature-ice.html (PhysOrg.com) — By confining water in nano-sized spaces, physicists from Leiden University in the Netherlands have turned water into ice at room temperature. While it’s not the first time scientists have created room-temperature ice, Dutch physicists K. B. Jinesh and Joost Frenken hope that their findings will put the controversial subject of water under nanoscale confinement in a new light. Explore further “The ice that forms in the confinement is normal ice; most probably, ice with a hexagonal lattice, which is the form of the most common crystalline ice seen in nature,” Jinesh said. The physicists also observed a few other ice formation traits. They found that, at higher humidities, ice appeared only to form under lower tip-scanning speeds compared to at lower humidities. This difference may be because high humidity causes the water film to be thicker, so that the molecules require more time for ordering, and need to be confined under the tip for a longer time.The researchers also observed evidence for static friction between the tip and the substrate, due to the ice formation. When the tip briefly paused, the ice had more time to become completely ordered, which made the tip “stick” more at that point in its stick-slip motion. “It is difficult to foresee an application at this level of invention,” Jinesh said. “The foreseeable difficulty is that in MEMS and NEMS, where the contact areas are shrinking in dimensions, ice formation could be a big problem that causes immediate failure of the devices. On the other hand, to increase friction wherever necessary, this technique could be employed, but it is so far a fiction, I would say!”More information: Jinesh, K.B. and Frenken, J.W.M. “Experimental Evidence for Ice Formation at Room Temperature.” Physical Review Letters 101, 036101 (2008).Copyright 2008 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 This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.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. Compared with other liquids, water behaves in strange ways. When under extreme confinement – such as when squeezed between two surfaces in an area of less than 10 molecular diameters (or 1 nm) – most liquid molecules become highly ordered, acquiring a solid-like structure. But in the case of water, several factors theoretically oppose the molecular ordering under confinement. For one thing, water is the only liquid that expands when it freezes, making it difficult for water to turn into ice when confined to a small space. Some physicists have proposed that water’s unique characteristics cause it to remain a liquid under confinement, while others argue that water solidifies under confinement, with each water molecule sharing hydrogen bonds with its neighbors. “Some simulations and even experiments have shown that water retains its liquid state and bulk viscosity even under extreme confinement, down to 0.1 nm,” Jinesh told PhysOrg.com. “At the same time, some other experiments have shown that the viscosity of water changes under confinement. This experimental controversy is the difficulty existing in literature to explain how water would behave as a lubricant under various situations.”In their recent study published in Physical Review Letters, Jinesh and Frenken have demonstrated direct experimental evidence for water transforming into ice at room temperature when confined between two objects. By scanning the tungsten tip of a high-res friction force microscope over a graphite surface, the physicists showed that the water trapped in between due to capillary condensation rapidly transforms into ice due to confinement. The current study builds on the team’s initial demonstration of ice formation under confinement in 2006, but with more solid information about the structure of the ice formed. “Our experiment undoubtedly demonstrates that water crystallizes at room temperature, under confinement,” Jinesh said. “This is a strong step towards resolving the existing controversy of whether or not water would change its bulk property due to confinement.”Here, the physicists investigated how scanning speeds and changes in relative humidity affected the tungsten tip’s scanning motion, as measured by a friction-sensitive Tribolever cantilever on the tip. At low scanning speeds and modest humidity, the tungsten tip exhibited stick-slip motion, alternately stopping and sliding. The physicists explained that this motion occurs because of the subsequent breaking and resolidification of the ice that is firmly attached to the tip and to the graphite. Only the molecules between the tip and graphite are solid ice, while everywhere else the molecules remain in a liquid water state. Dust storms swirl at the north pole of Mars
© 2010 PhysOrg.com Citation: 3D bio-printers to print skin and body parts (2011, February 24) retrieved 18 August 2019 from https://phys.org/news/2011-02-3d-bio-printers-skin-body.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. 3D printers print by depositing material line by line and then vertically layer by layer. They have been used to make sculptures and repair sculptures, to make three-dimensional objects out of plastics and polymers, and even to print food.Professor James Yoo, from the Institute of Regenerative Medicine at Wake Forest University in Winston-Salem, North Carolina told the annual meeting of the American Association for the Advancement of Science (AAAS) his group is developing a system that will allow them to print skin directly onto burn wounds.Yoo’s team were motivated to develop a portable bioprinting system by the injuries arising on battlefields in Iraq and Afghanistan, where around 30 percent of injuries involve the skin. Their research is funded by the US Department of Defense.The bioprinter has a built-in laser scanner that scans the wound and determines its depth and area. The scan is converted into three-dimensional digital images that enable the device to calculate how many layers of skin cells need to be printed on the wound to restore it to its original configuration. The system has successfully printed skin patches 10 cm square on a pig.Also at the AAAS meeting was the director of Cornell University’s Computational Synthesis Laboratory, Professor Hod Lipson, who demonstrated a bioprinter by printing an ear, working from a scan of a human ear and a computer file containing the three-dimensional coordinates. The ear was printed using silicone gel instead of real human ear cells.The Cornell team has already published results on their experiments to bioprint repairs to damaged animal bones, but Professor Lipson said there were a number of technical challenges still to overcome. He said the first use is likely to be repairs to cartilage, since it has a fairly simple internal structure with little vascularization. Bioprinting cartilage has been tried “fairly successfully” in animal models, and the team have successfully printed cartilage cells directly into the meniscus of an injured knee to reconstruct it.One of the major challenges to be faced in bioprinting is the connection between the bioprinted material and the rest of the body, especially with larger tissues, since any organ or body part that is printed will need to be connected to the body’s blood vessels, and this can be very difficult. Regardless of the challenges, Professor Lipson believes bioprinting will become a standard technique within a couple of decades. Ink-jet printers inspire scientists to make skin (PhysOrg.com) — The range of uses for three-dimensional printers is increasing all the time, but now scientists are developing 3D “bioprinters” that will be able to print out skin, cartilage, bone, and other body parts. Cornell University researchers have engineered an ear made of silicone using a 3D bio-printer. Explore further
Journal information: Proceedings of the National Academy of Sciences MIT wins Pentagon prize in social networking contest Findability of targets in the New York and New Jersey areas. Credit: A. Rutherford. Citation: Researchers root out the limits of social mobilization (2013, April 2) retrieved 18 August 2019 from https://phys.org/news/2013-04-root-limits-social-mobilization.html The researchers built simulations using data from the DARPA Challenge, adding in both demographic and geographic data and the strategy used by the team that won. They found that one of the critical factors to success was a central leader who not only had many social ties to begin with, but also was skillful at getting the word out very quickly. They also found what they call “small world” connections to be important—it’s where a few core people who participate are scattered over large geographic areas. And finally, they note that finding the balloons also depended on the population density of the people looking for them and of course how much they stuck out in the area where they were “hidden.” Thus, sometimes, they found, there are certain conditions unique to the challenge that can mean the difference between success and failure. (Phys.org) —A team of international researchers working together to better understand how social mobilization works, has built a model using data obtained by the DARPA Network Challenge in 2009. In their paper published in the Proceedings of the National Academy of Sciences, they say their results show that social mobilization only appears to be successful under optimum circumstances. 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. More information: Limits of social mobilization, PNAS, Published online before print April 1, 2013, doi: 10.1073/pnas.1216338110AbstractThe Internet and social media have enabled the mobilization of large crowds to achieve time-critical feats, ranging from mapping crises in real time, to organizing mass rallies, to conducting search-and-rescue operations over large geographies. Despite significant success, selection bias may lead to inflated expectations of the efficacy of social mobilization for these tasks. What are the limits of social mobilization, and how reliable is it in operating at these limits? We build on recent results on the spatiotemporal structure of social and information networks to elucidate the constraints they pose on social mobilization. We use the DARPA Network Challenge as our working scenario, in which social media were used to locate 10 balloons across the United States. We conduct high-resolution simulations for referral-based crowdsourcing and obtain a statistical characterization of the population recruited, geography covered, and time to completion. Our results demonstrate that the outcome is plausible without the presence of mass media but lies at the limit of what time-critical social mobilization can achieve. Success relies critically on highly connected individuals willing to mobilize people in distant locations, overcoming the local trapping of diffusion in highly dense areas. However, even under these highly favorable conditions, the risk of unsuccessful search remains significant. These findings have implications for the design of better incentive schemes for social mobilization. They also call for caution in estimating the reliability of this capability. Explore further © 2013 Phys.org Social mobilization is a new phenomenon—it’s where people connected together through social media such as Facebook and Twitter all strive to achieve a goal of some sort. One recent example was millions of people switching their Facebook profile picture to display a white “=” over a red background in support of same-sex marriage as the U.S. Supreme court was grappling with the issue recently. Other examples are people using social media to overthrow a government or to help find missing children.But, because social mobilization is so new, relatively little is known about it, such as what conditions make for successful campaigns, and which don’t. To find out, the diverse group of researchers looked to the DARPA Network Challenge which was held in 2009. There 10 weather balloons were hidden in various locations in the continental United States and a reward of $40,000 was offered to whoever found them all first. The team that won, from MIT, used a very coordinated social mobilization effort and located all ten balloons in less than nine hours. Another similar effort called the “Tag Challenge” was run by the U.S. Department of State and the U.S. Embassy in Prague last year. That challenge was won by an International team of researchers also using social mobilization. In this new effort, the researchers created simulations that best describe the conditions that exist when social mobilization efforts get underway. Tying all three efforts together is computer scientist Manuel Cebrian now at the University of California—he was on the winning team for both challenges and is a member of this new effort as well. Map of Population Density (logarithmic scale, per km2) Across Mainland USA and Locations of Balloons in Red Balloon Challenge. (Lambert Azimuthal Equal Area Projection). Credit: (c) PNAS, 10.1073/pnas.1216338110
© 2014 Phys.org Characteristic change in air stagnation components. Credit: Nature Climate Change (2014) doi:10.1038/nclimate2272 Stagnation is an atmospheric phenomenon where an air mass remains in place over a geographic region for an extended period of time. They tend to happen due to the convergence of specific weather conditions—light wind patterns near the surface, other light wind patterns occurring higher up, and a lack of rain. During normal weather periods, wind and rain combine to clean the air around metropolitan areas—when rain fails to fall and there is little wind to push pollution away from an area, particulates and other types of pollution levels climb, putting those that live in the area at risk of health problems.The collection of computer models run by the team at Stanford also suggest that stagnation events are likely to last longer—increasing by an average of 40 days a year. The result the team notes, is likely to be an increase in heart and lung complications in people in those areas, contributing to an associated climb in the number of premature deaths due to air pollutants—numbering perhaps in the millions. They also note that Mexico, India and parts of the western U.S. are likely to be most at risk of health impacts from an increase in stagnation events, as all three will have more and longer such events and all three are heavily populated.The researchers suggest that at some point, the entire planet will be impacted by stagnation events. That means governments and health workers will need to make plans on how to handle the problems as they begin to occur. They add that the only real solution to the problem is to begin curbing greenhouse gas emissions now, preventing the events from occurring in the first place. Journal information: Nature Climate Change Researchers predict global warming will cause an increase in frequency of Indian Ocean Dipole events More information: Occurrence and persistence of future atmospheric stagnation events, Nature Climate Change (2014) DOI: 10.1038/nclimate2272AbstractPoor air quality causes an estimated 2.6–4.4 million premature deaths per year. Hazardous conditions form when meteorological components allow the accumulation of pollutants in the near-surface atmosphere. Global-warming-driven changes to atmospheric circulation and the hydrological cycle are expected to alter the meteorological components that control pollutant build-up and dispersal, but the magnitude, direction, geographic footprint and public health impact of this alteration remain unclear. We used an air stagnation index and an ensemble of bias-corrected climate model simulations to quantify the response of stagnation occurrence and persistence to global warming. Our analysis projects increases in stagnation occurrence that cover 55% of the current global population, with areas of increase affecting ten times more people than areas of decrease. By the late twenty-first century, robust increases of up to 40 days per year are projected throughout the majority of the tropics and subtropics, as well as within isolated mid-latitude regions. Potential impacts over India, Mexico and the western US are particularly acute owing to the intersection of large populations and increases in the persistence of stagnation events, including those of extreme duration. These results indicate that anthropogenic climate change is likely to alter the level of pollutant management required to meet future air quality targets. Explore further (Phys.org) —A new study conducted by researchers at Stanford University has led to findings indicating that much of the world can expect to have more atmospheric stagnation events as the future unfolds. In their paper published in Nature Climate Change, the researchers describe how they ran a variety of computer models that took into account a continued increase in greenhouse gas emissions—they report that taken together, the models predict that approximately 55 percent of the world’s population can expect to be impacted by future stagnation events. Citation: New study suggests more and longer atmospheric stagnation events due to global warming (2014, June 23) retrieved 18 August 2019 from https://phys.org/news/2014-06-longer-atmospheric-stagnation-events-due.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.
Explore further Citation: Two new Saturn-mass exoplanets discovered (2017, May 8) retrieved 18 August 2019 from https://phys.org/news/2017-05-saturn-mass-exoplanets.html The planets were discovered by researchers working as part of the Optical Gravitational Lensing Experiment (OGLE) group and the Microlensing Observations in Astrophysics (MOA) collaboration. OGLE uses the 1.3-m Warsaw Telescope located at Las Campanas Observatory in Chile, while MOA utilizes the 1.8-m MOA-II telescope at the Mount John University Observatory, located in New Zealand. The main goal of these two microlensing surveys is to study the planet formation around late-type stars.Gravitational microlensing is an invaluable method of detecting new extrasolar planets circling their parent stars relatively closely. This technique is sensitive to planets orbiting beyond the so-called “snow line” around relatively faint host stars like M dwarfs or brown dwarfs. It is a location in the proto-planetary disk where the water ice may condense and where gas giant planets are believed to be formed. Therefore, understanding the distribution of exoplanets in this region could offer important clues to how planets form.Recently, OGLE and MOA scientists led by Przemek Mróz of the Warsaw University Observatory in Poland, have found planetary anomalies in two faint microlensing events designated OGLE-2013-BLG-0132 and OGLE-2013-BLG-1721. “Both events showed clear deviations from the simple point-source point-lens model, caused by the presence of a second body with well-measured planet-to-host mass ratios of (5.15 ± 0.28) x 10-4 and (13.18 ± 0.72) x 10-4, respectively,” the researchers wrote in the paper.The newly discovered planets received designation OGLE-2013-BLG-0132b and OGLE-2013-BLG-1721b. Both planets likely belong to a group of sub-Jupiter-mass planets orbiting M dwarfs beyond the snow line distance.According to the research, OGLE-2013-BLG-0132b has a mass of about 0.29 Jupiter masses and orbits its parent star at a distance of 3.6 AU. The planet’s host is located about 12,700 light years away and has a mass of approximately 0.54 solar masses. With a mass of about 0.64 Jupiter masses, OGLE-2013-BLG-1721b is circling its host (0.46 solar masses) at a distance of 2.6 AU. This planetary system is located some 20,500 light years away from the Earth.The researchers estimated the masses of the planets using the Bayesian analysis as both events were short and faint, which prevented them from measuring a reliable parallax signal.”Both events were too short and too faint to measure a reliable parallax signal and hence the lens mass. We therefore used a Bayesian analysis to estimate masses of both planets,” the paper reads.The team noted that in order to uncover more properties of the two newly discovered planetary systems, follow-up high-resolution imaging observations should be conducted in the future. In particular, the Near InfRared Camera (NIRCam) on the James Webb Space Telescope (JWST) that will be launched into space in late 2018, could reveal important insights about these new Saturn-mass exoworlds. Light curve of OGLE-2013-BLG-0132. The inset shows the enlargement of the caustic crossing parts of the light curve. The lower panel shows the residuals from the best-fit model. Credit: Mróz et al., 2017. 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. (Phys.org)—An international team of astronomers has detected two new giant alien worlds circling distant stars. The newly found planets are estimated to be as massive as Saturn and are orbiting M dwarfs beyond the snow line. The findings were presented May 2 in a paper published online on the arXiv pre-print server. More information: OGLE-2013-BLG-0132Lb and OGLE-2013-BLG-1721Lb: Two Saturn-mass Planets Discovered around M-dwarfs, arXiv:1705.01058 [astro-ph.EP] arxiv.org/abs/1705.01058AbstractWe present the discovery of two planetary systems consisting of a Saturn-mass planet orbiting an M-dwarf, which were detected in faint microlensing events OGLE-2013-BLG-0132 and OGLE-2013-BLG-1721. The planetary anomalies were covered with high cadence by OGLE and MOA photometric surveys. The light curve modeling indicates that planet-host mass ratios are (5.15±0.28)×10−4 and (13.18±0.72)×10−4, respectively. Both events were too short and too faint to measure a reliable parallax signal and hence the lens mass. We therefore used a Bayesian analysis to estimate masses of both planets: 0.29+0.16−0.13 MJup (OGLE-2013-BLG-0132Lb) and 0.64+0.35−0.31 MJup (OGLE-2013-BLG-1721Lb). Thanks to a high relative proper motion, OGLE-2013-BLG-0132 is a promising candidate for the high-resolution imaging follow-up. Both planets belong to an increasing sample of sub-Jupiter-mass planets orbiting M-dwarfs beyond the snow line. © 2017 Phys.org Massive exoplanet discovered using gravitational microlensing method
Implementing the single-molecule DNA navigator. a) Schematic illustration of the PSEC system. An acyclic connected graph (i.e. a tree) is constructed on a rectangular DNA origami substrate of 100 x 70 nm^2. T1 and T2 are two types of fuels driving the PSEC on the tree. Initiator I was used to trigger the initiation of the PSEC from the entrance vertex ENT. b) propagation mechanism of the PSEC system. Initiator I recognizes and opens the T1ent hairpin at vertex ENT. The opened hairpin then captures and opens a T2 hairpin from the environment to start the cascade. c) A straight line paved by PSEC and visualized with DNA-PAINT. d) Four paved digits of “2017” imaged using atomic force microscopy (AFM). The T1 hairpins at the corner points were modified to prevent unwanted spans. The arrows indicate the direction of propagation. Credit: Nature Materials, doi: 10.1038/s41563-018-0205-3. © 2018 Science X Network Tying the knot: New DNA nanostructures , Science In the present study by Chao et al, the same basic principle of the HCR reaction scheme was used in a different computational context to develop a single-molecule DNA-navigator system. The platform explored all possible paths through a tree graph designed on an origami structure as a simply connected maze without cyclic paths. Such DNA origami structures are information-bearing nanostructures by nature with well-defined nanoscale geometry. The maze could be explored by proximal strand exchange cascade (PSEC) based on hybridization chain reactions. The researchers demonstrated that a system with a large number of single-molecule DNA navigators could collectively conduct parallel depth-first search (PDFS) on the tree to efficiently perform maze solving within 2-D origami. Initially the researchers conducted studies to test the PSEC design. Journal information: Nature Materials Citation: Solving mazes with single-molecule DNA navigators (2018, November 16) retrieved 18 August 2019 from https://phys.org/news/2018-11-mazes-single-molecule-dna.html More information: Jie Chao et al. Solving mazes with single-molecule DNA navigators, Nature Materials (2018). DOI: 10.1038/s41563-018-0205-3Renjun Pei et al. Training a molecular automaton to play a game, Nature Nanotechnology (2010). DOI: 10.1038/nnano.2010.194S. M. Douglas et al. A Logic-Gated Nanorobot for Targeted Transport of Molecular Payloads, Science (2012). DOI: 10.1126/science.1214081 Kinetics of the process were investigated at the single-molecule level in the study using time-resolved total internal reflection fluorescence microscopy (TIRF) in a setup with a prescribed starting point (P0) and five intermediate steps (P1-P5). Fluorescence in the setup was quenched using fluorescence resonance energy transfer (FRET), and the cascade was observed in real time by recording fluorescence signals continuously. The average speed of propagation was recorded to be 2.46 nm per minute, propagation across the straight line (54.4 nm) took approximately 22 minutes. The scientists then constructed the main model maze with 10 vertices that included an entrance vertex A and an exit vertex J, three junctions (B, D, E) an intermediate vertex (I) and four dead ends (C, F, G, H). Each path of the maze that was equivalent to a tree with 10 vertices was investigated using DNA investigators starting at root A. The PSEC reactions produced a mixture of various paths on the maze, confirmed with AFM. Each individual PSEC could progress on one of the five possible paths. Statistical analysis of the length distribution showed that the measured paths coincided well with the values predicted. To prevent the navigators from propagating through a wrong path with dead ends, the scientists designed a streptavidin-biotin tag-based method to selectively eliminate inaccurate path navigation. Only the correct path (PABDIJ) was followed in the maze therefore. The computational context used in the study allowed exploration of paths through tree graphs defined on the origami. The autonomous path explored by the DNA navigators proceeded unidirectionally and irreversibly, turning at junctions and corners on the origami platform as they were designed to. The design enabled parallel depth first search (PDFS) allowing each DNA navigator to individually explore any one of the paths through the given graph at a defined speed, greater than that previously achieved. The main advantage of the described biomolecular computer schemes in comparison to conventional electronic computing is they can be interfaced directly with biologically relevant processes. As a result, the scientists envision translational biomedical sensing and decision-making platforms with DNA origami and single-molecule diagnostics using decision trees. Future applications will also include simple sensors or those coupled to a molecular actuator to trigger downstream molecular cascades. , Nature Nanotechnology Pathfinding operations with DNA navigators make use of a localized strand exchange cascade process initiated at a unique trigger site on the origami platform. Automatic progression along paths is enabled by DNA hairpins containing a universal traversal sequence. By design, each single-molecule navigator can autonomously explore any of the possible paths through a 10-vertex rooted tree constructed in the study. The mazes were equivalent to a tree with an entrance at the root and an exit through one of the leaves. The study conducted by Jie Chao and co-workers resulted in exploring all paths taken by the DNA navigators to extract a specific solution path that connected a given pair of start and end vertices in the maze. As a result, the solution path was laid plainly on the origami platform and illustrated using single-molecule imaging. The approach is now published in Nature Materials, detailing the realization of molecular materials with embedded biomolecular computational functions to operate at the level of the single-molecule with potential to engineer intelligent nanorobots for future applications in industry and medicine.Sophisticated molecular tools were used in the past to create molecular machines that convert chemical, photonic or electric energy into rotary or linear movements at the nanoscale. For instance, Brownian motion at the nanoscale can be controllably converted into directed movements within DNA-based nanomachines using DNA hybridization reactions. Such DNA-based machines operate autonomously by following an embedded ‘molecular program’ pre-designed as a cascade reaction manually triggered via an external stimulus for each step of the operation. The focus of the field has progressively shifted to actualize DNA-based logic circuits using aptamers and DNAzymes to design molecular logic gates. For example, in 2006, Stojanovic and co-workers integrated more than 100 DNA logic gates to engineer an automation calledMAYA-II to play a game of Tic-Tac-Toe. Preceding studies demonstrated an enzyme free computing system based on hybridization chain reactions (HCR) to create logic-gates and logic circuits for more robust and efficient performance than the original systems. Single-molecule DNA navigators for maze-solving. a) Schematic illustration of magnetic bead-based selection. Exit vertex J is labelled with biotin to enable differentiation between the correct and wrong paths. Only if the PSEC reaches the correct exit J, would the biotin-modified T1exit-B strand be released. All wrong paths could be captured and removed by the Streptavidin-modified magmatic beads therefore. b) Details of the release of biotin modification at the exit J by the PSEC. c) AFM characterization of the correct solution after selection. The remaining structures all showed the correct solution path PABDIJ. d) Single-molecule and class-averaged DNA-PAINT characterization of the correct solution after selection. Credit: Nature Materials, doi: 10.1038/s41563-018-0205-3. Explore further The proximal strand exchange cascade (PSEC) system (working principle of the DNA navigator) was facilitated on a rectangular origami substrate made of three components, which included the physical implementation of a tree graph, full strands and an initiator strand. Vacant areas without staple extensions corresponded to walls in the maze, preventing propagation of the strand exchange cascade. The entrance and exit were defined and denoted as ENT and EXIT respectively. In the second component, two types of DNA hairpins, T1 and T2, were used as fuels to drive the PSEC on the tree graph. The two hairpins coexisted metastably in solution to hybridize and fuel the PSEC process with free energy . By design, information only propagated through the network in the presence of an initiator (Initiator I). Upon addition of initiator I, PSEC was conducted and observed using atomic force microscopy (AFM). To visualize an established formation, the scientists enabled DNA-navigator-based formation of the number 2017 as a proof-of-principle. Another technique known as DNA-PAINT was employed as a single-molecule, super-resolution imaging technique to reveal molecular features at the nanoscale to further substantiate the PSEC-based path paving process. The on-origami PSEC was highly specific, without intra- or inter-origami crosstalk. The field of intelligent nanorobotics is based on the great promise of molecular devices with information processing capabilities. In a new study that supports the trend of DNA-based information carriers, scientists have engineered a DNA navigator system that can perform single-molecule, parallel, depth-first search operations on a two-dimensional origami platform. Single-molecule characterization of PSEC kinetics. a) A straight line in the middle of the DNA origami was used as the test bed. Vertex P0 is the starting point and vertices P1-P5 are intermediate points. b) Details of the design of six parallel tests to measure the kinetics with time-resolved TIRF. T2 labelled with BHQ2 was used to quench T1 labelled with Cy3, assembling a kinetic profile at each step. The illustrated example shows the mechanism of quenching. c) Example TIRF images show the fluorescence changing with time across the six parallel tests from P0 to P5. d) Typical single-molecule fluorescence traces used to monitor quenching events occurring at vertices P0 to P5. e) Scatter plots showing statistical analysis of the length distribution per path. Credit: Nature Materials, doi: 10.1038/s41563-018-0205-3. 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. The PSEC-driven graph traversal on a maze. a) A maze design with 10 vertices. Arrows indicate the entrance vertex A and exit vertex J. b) The maze is equivalent to a rooted tree with 10 vertices. The entrance vertex A corresponds to the root of the tree. c) An AFM image showed the result of a transversal experiment generating all possible paths. In this DNA computing implementation of a PDFS algorithm, a vast number of PSEC events simultaneously occurred to realize the graph traversal on the maze. PSEC ending at the exit or deadends were highlighted in red circles. Invalid structures were highlighted with white circles. d) Typical paths found in the mixture seen from left to right. Only PABDIJ was the correct solution to the maze. e) Scatter plots showing the statistical analysis of the length distribution for each path. Credit: Nature Materials, doi: 10.1038/s41563-018-0205-3.
You decide what you watch. That is the funda behind Humour Me’s Improv Nights. Here audience is the king as artistes will improvise on the spot in order to entertain you. Their one-hour performance on Sunday saw an entertaining stand-up performance where they improvised on the spot, spontaneously without any pre-written script. The audience drove the theme of each segment of the show. Humour Me is a group of four performers and one host. The artistes performing at Improv Nights are Dhruv Sachdeva, Clifford Alfonso, Andrew Hoffland, Pranay Manchanda and Shantanu Anam. Also Read – ‘Playing Jojo was emotionally exhausting’Dhruv Sachdeva takes up the role of the host and is also the founder of Humour Me and has been in the entertainment world for the past 10 years. He started his acting career with the role of Scar in the musical Circle of Life which is an adaptation of the Broadway musical The Lion King’ Last year, Dhruv produced and acted in the production The Character of a Happy Life. And most recently, wrote, directed and acted in an original musical theatre production Also Read – Leslie doing new comedy special with NetflixDinner for Pricks, under the Humour Me banner.So the audience gives them a situation or a scene to enact, and they perform it on the spot — with sound effects and even mimicry et al in place.‘We basically perform as per the demand of the audience which includes different dance forms like rap, conventional etc and various music genres too,’ said Dhruv.Clifford started years back with the musical production Noah’s Ark. Andrew Hoffland, oldest of all the performers, works as a teacher and has been singing and acting in various theatrical and musical productions. Pranay Manchanda has been an actor for over 15 years, and has worked in theatre.Shantanu Anam has worked as is an actor from the age of 16, and has acted and directed several theatre productions. ‘We are here to deliver happiness, not shoes. If we don’t stick in your mind, we consider we have have failed,’ said Dhruv. Fair enough!DETAILAt: Lure Switch, Lado Sarai when: 23 December
The gradual evolution of modernism in India in the post-independence era is a unique tale of artistic endeavors. Unending struggles and progression of vision against all odds by the artistes to give birth to and deliver their individualistic language/s in art that made them the great masters of Indian art of the twentieth century. The artworks of these masters thus stand on their own to mark the emblematic journeys of each creator. The empowerment and enlightenment they could attain in their lifetime is far beyond the realm of material success and social recognition. Even in the second decade of the 21st century, the relevance of modernism is as apt and significant in the field of visual arts as it was at the time of its inception. Also Read – ‘Playing Jojo was emotionally exhausting’Aakriti Art Gallery have organised a show showcasing the works of such masters of visual arts in India along with a few young creators who are steadily making their way into the field, in this edition of the India Art Fair 2015.Works of the stalwarts of Indian visual arts – Ram Kumar, Jogen Chowdhury, Satish Gujral and Partha Pratim Deb will be showcased. Sculptures by Akhil Chnadra Das, Asim Basu, Subrata Biswas and Tapas Biswas will be on exhibit. Thus, the whole idea is to generate a gamut of different genres of modern Indian art and its due course of progress into post-modern and henceforth. The display will be a blend of various flavours to cater its audience with the best of tenets that Indian art has so far created and nurtured. Also Read – Leslie doing new comedy special with NetflixOn one hand, if it’s the power and magic of distorted lines and stokes by Jogen Chowdhury, on the other it will a romantic blend of shades and different moods of nature in semi-real abstract forms which Ram Kumar is best known for. Again where there will be poetic tales of life and death, bonding and partition with figures and solid patches of opaque colours on large canvases depicting the greater philosophy of life by Satish Gujral, there will also be subtle nuances of day-to-day living, anguishes in disguise and the critique to subjugation in Partha Pratim Deb’s vivid experimentation with different mediums on the canvas plane. The sculpture section by these young sculptors are made by through their execution in different materials and mediums – wood, metal and stone and so on. From devising the tales from myths and folklore by Subrata Biswas experimenting with metal, we will get to observe the finesse of sculpting in great volumes inTapas Biswas’s works who gives voice to the crisis of mankind and the nation through his execution. It will be a set of experimentation by Asim Basu in his sculpting style and Akhil Chandra Das who has been explicitly dealing with organic reality and the essence of human values in his sculptures will add another dimension in the new series of works to be showcased in the India Art Fair.
In Iraq’s western province of Anbar, hundreds of soldiers, police officers, Shia and Sunni militias launched an operation in the militant-seized town of al-Baghdadi, some 200 km northwest of the Iraqi capital Baghdad.They retook control of part of the town, including its main police headquarters, after heavy clashes with the IS militants, Xinhua cited a provincial security source as saying. The clashes left more than 20 militants killed, the source said without giving details about the casualties of the security members. Also Read – Pro-Govt supporters rally as Hong Kong’s divisions deepenThe security forces repelled an IS attack on a neighbourhood adjacent to al-Baghdadi, which was the scene of fierce clashes two days ago, leaving at least four IS fighters killed, including two suicide bombers, the source added.On Saturday, the security forces broke the siege of the neighbourhood which is housing some 1,000 families of security personnel and government-backed Sahwa paramilitary group members. They have been trapped for about 10 days and the families have suffered from acute shortage in food and drinking water. Separately, US and partner-nation warplanes conducted air strikes on IS positions near a bridge outside the militant-seized city of Fallujah, some 50 km west of Baghdad, killing at least five militants and wounding seven others. Also Read – Pak Army ‘fully prepared’ to face any challenge: Army spokesmanElsewhere, warplanes of the US-led coalition on late Sunday night hit an IS convoy outside a village near the town of Daqouq, some 40 km south of Iraq’s northern city of Kirkuk, destroying two vehicles and killing some 18 militants aboard, a security source said.In Iraq’s northern central province of Salahudin, heavy clashes erupted near the town of Is’haqi, some 90 km north of Baghdad, between the security forces and dozens of IS militants who attacked a military base, leaving at least five extremist militants killed.The security situation in Iraq has drastically deteriorated since June 10 last year, when bloody clashes broke out between Iraqi security forces and the IS, an Al Qaeda offshoot.
The Delhi High Court on Wednesday asked the Delhi University not to treat its the three law colleges, which have been in controversy recently for alleged non-compliance of the Bar Council Of India (BCI) norms, in a “step-motherly” way.A bench of Chief Justice G Rohini and Justice Rajiv Sahai Endlaw said that the Delhi University’s (DU) law schools are very much part of the varsity and closing down will affect the future of the students. “The three law centres are very much part of the DU,” the court said, adding that they should not be treated in a a step-motherly way. The court said this when it was informed that the BCI inspection committee that had visited and reported on the state of affairs was of the firm view that the DU’s three law schools should be closed down. The inspection committee has recommended that the DU’s law centres failed to comply with 17 conditions listed and it should not be allowed to admit new batches of students. The court was hearing a PIL filed by Tarun Narang seeking setting aside of a notification barring fresh law graduates of the DU from being enrolled as lawyers.