At left, a sketch of two grids connected by two generic sticky-ends (circled) and one specific sticky-end (right end). The atomic force microscopy image is at right, with the scale bar equal to 40 nm. Credit: Constantin Pistol, et al. DNA could be backbone of next generation logic chips In the second method, Pistol and Dwyer used all specific sticky-ends to connect two 4 x 4 grids. They found that, after the grids were connected, the sticky-ends could be reused in other connections. In this method, the scientists assembled four 4 x 4 grids to produce a 64-motif structure. “Once the two sticky-ends have joined into a double helix, their sequences can be re-used in another part of the system,” said Dwyer. “This requires that the nanostructure be formed hierarchically.”At a molecular weight of 8960 kD, the 64-motif structure is one of the largest programmable synthetic nanostructures ever synthesized. The scientists also predict that this method can be scaled even further before reaching a limit imposed when the generic interactions begin to dominate the process. However, studies in periodic DNA crystal formation suggest that the scale limit is nearly macroscopic.In analyzing their structures for defects, Pistol and Dwyer found that missing motifs were common, requiring defect-tolerant designs in future large-scale assemblies. If DNA nanostructures can be fabricated at the scales Pistol and Dwyer predict, then not only biotechnology and the pharmaceutical industry would benefit, but future computer systems may use DNA, as well.“One of the benefits of DNA nanostructures for computers is device density,” Dwyer said. “The grid has a pitch of 20nm, and this is about half of the smallest device feature in Intel’s latest lithography process. The other benefit is manufacturing scale. Each experiment created a vast number of structures (~1012 or more) and this holds the promise of more complex and higher performance computers in the future.”Citation: Pistol, Constantin, and Dwyer, Chris. “Scalable, low-cost, hierarchical assembly of programmable DNA nanostructures.” Nanotechnology 18 (2007) 125305 (4pp).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 This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. In their recent paper in Nanotechnology, Constantin Pistol and Chris Dwyer explain DNA’s advantages over silicon in terms of its easy synthesis, control and asymmetrical complexity. While recent advances in the field of fabricating DNA nanostructures have produced rigid sequences, Pistol and Dwyer focused on developing a self-assembly method that enables simple and inexpensive scaling of the DNA structures. In addition, their grid-like structures consist of components that can be independently modified to create arbitrary patterns for different purposes.“The independent chemical modification of the motifs in the grid is important when generating templates on the grid,” Dwyer told PhysOrg.com. “Our computer architecture research is investigating how the DNA grids might act like scaffolds for other materials, such as carbon nanotubes. Arbitrary patterns of these materials are necessary to implement the kinds of circuits that we use to build computers.” The hierarchical approach to building nanostructures from DNA, beginning with nine oligonucleotides and resulting in an 8 x 8 grid. Credit: Constantin Pistol, et al. In their study, the scientists use a hierarchical approach: nine oligonucleotides (the structural units of DNA) form a cross-like motif, and 16 motifs annealed with streptavidin can form a grid. To build larger structures from these 4 x 4 grids, the scientists experimented with using two types of sticky-ends. “Sticky-ends are single-stranded pieces of DNA that can hybridize, or form a double helix, with their complements,” Dwyer explained. “A well designed sticky-end has only one true complementary sticky-end in the system.”The first type, the “generic” sticky-end, binds with only one helix instead of the normal two. This binding provides a relatively unstable interaction, which makes it easier to individually program two adjacent grids later on. The second type, the “specific” sticky-end, provides a stronger interaction and can control the weak interactions between the generic sticky-ends.In one fabrication method, the scientists bound together two 4 x 4 grids, using two generic sticky-ends and one specific sticky-end (the fourth grid arm was left open for identification purposes). The scientists found that the single specific sticky-end could dominate the entire connection, providing a scalable assembly method. Explore further Citation: For low-cost DNA nanostructures, recycle sticky ends (2007, March 2) retrieved 18 August 2019 from https://phys.org/news/2007-03-low-cost-dna-nanostructures-recycle-sticky.html Scientists from Duke University have recently demonstrated a new method for assembling large, low-cost DNA nanostructures, in part by reusing the “sticky-ends,” the broken DNA strands used to connect the nanostructures. In their hierarchical self-assembly method, the scientists have demonstrated one of the largest programmable synthetic nanostructures ever synthesized. 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.
J and K band AO imaging of HD 87646 taken at Palomar observatory. Credit: Ma et al., 2016. (Phys.org)—An international team of astronomers reports the discovery of a giant planet and a brown dwarf in a close binary system designated HD 87646. The findings, described in a paper published Aug. 11 on arXiv.org, reveal that HD 87646 is the first close binary system with more than one substellar circum-primary companion known to date. Citation: Giant planet and brown dwarf discovered in a close binary system HD 87646 (2016, August 16) retrieved 18 August 2019 from https://phys.org/news/2016-08-giant-planet-brown-dwarf-binary.html Explore further © 2016 Phys.org More information: Very Low-Mass Stellar and Substellar Companions to Solar-like Stars From MARVELS VI: A Giant Planet and a Brown Dwarf Candidate in a Close Binary System HD 87646 , arXiv:1608.03597 [astro-ph.EP] arxiv.org/abs/1608.03597AbstractWe report the detections of a giant planet (MARVELS-7b) and a brown dwarf candidate (MARVELS-7c) around the primary star in the close binary system, HD 87646. It is the first close binary system with more than one substellar circum-primary companion discovered to the best of our knowledge. The detection of this giant planet was accomplished using the first multi-object Doppler instrument (KeckET) at the Sloan Digital Sky Survey (SDSS) telescope. Subsequent radial velocity observations using ET at Kitt Peak National Observatory, HRS at HET, the “Classic” spectrograph at the Automatic Spectroscopic Telescope at Fairborn Observatory, and MARVELS from SDSS-III confirmed this giant planet discovery and revealed the existence of a long-period brown dwarf in this binary. HD 87646 is a close binary with a separation of ∼22 AU between the two stars, estimated using the Hipparcos catalogue and our newly acquired AO image from PALAO on the 200-inch Hale Telescope at Palomar. The primary star in the binary, HD 87646A, has Teff = 5770±80K, log(g)=4.1±0.1 and [Fe/H] = −0.17±0.08. The derived minimum masses of the two substellar companions of HD 87646A are 12.4±0.7MJup and 57.0±3.7MJup. The periods are 13.481±0.001 days and 674±4 days and the measured eccentricities are 0.05±0.02 and 0.50±0.02 respectively. Our dynamical simulations show the system is stable if the binary orbit has a large semi-major axis and a low eccentricity, which can be verified with future astrometry observations. 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. HD 87646, located around 240 light years away, is a bright G-type star with a fainter K-type stellar companion. The primary star in the system, HD 87646A, is about 12 percent more massive than the sun and has a radius of about 1.55 solar radii. The system has a separation of only 22 AU between the two stars.A team of researchers, led by Bo Ma of the University of Florida, has been observing HD 87646 since 2006 using a set of telescopes. The scientists employed the W.M. Keck Exoplanet Tracker (KeckET), at the Sloan Digital Sky Survey (SDSS) 2.5m telescope, mounted on the Apache Point Observatory in New Mexico to reveal the presence of a new giant planet that received designation HD 87646b. KeckET is a new generation multiple object Doppler instrument, capable of simultaneously observing more than 50 stars.The planetary status of HD 87646b was confirmed thanks to the radial velocity observations conducted by utilizing the Kitt Peak National Observatory (KPNO) in Arizona, the High-Resolution Spectrograph at the Hobby-Eberly Telescope (HET) in Texas, the “Classic” spectrograph at the Automatic Spectroscopic Telescope, mounted on the Fairborn Observatory in Arizona and the Multi-object APO Radial Velocity Exoplanet Large-area Survey (MARVELS) at SDSS. Moreover, these observations allowed the researchers to detect new even larger companion in the system – a brown dwarf designated HD 87646c.”Our SDSS MARVELS pilot survey and additional observations at the HET, KPNO 2.1m telescope, and Fairborn Observatory confirm the detection of two massive substellar companions in a close binary system HD 87646,” the team wrote in the paper.According to the study, HD 87646b has a minimum mass of about 12.4 Jupiter masses and an orbital period of approximately 13.5 days. HD 87646c is much more massive, having 57 Jupiter masses and much longer orbital period, circling the star every 673 days.The team also conducted dynamical simulations of the system, which allowed them to draw conclusions that HD 87646 is stable if it has a large binary semi-major axis and a relatively low binary eccentricity.However, the question of how this system was formed still baffles the authors of the paper. Given the fact that HD 87646 is the first known system to have two massive substellar objects orbiting a star in a close binary and the masses of the two objects are close to the minimum masses for burning deuterium and hydrogen, these peculiarities raise questions about the system’s formation and evolution.”The large masses of these two substellar objects suggest that they could be formed as stars with their binary hosts: a large molecular cloud collapsed and fragmented into four pieces; the larger two successfully became stars and formed the HD 87646 binary, and the other smaller ones failed to form stars and became the substellar objects in this system. This scenario might be relevant for the binary stars but seems problematic for the two substellar objects on orbits within one AU because it is unclear whether fragmentation on such a small scale can occur,” the paper reads.Other hypothesis offered by the scientists is that the two newly discovered giant objects were formed like giant planet in a protoplanetary disk around HD 87646A. However, they added that such massive disks are rare in close binaries, and further investigation is needed to confirm this explanation. Astronomers discover new substellar companion to the Pleiades member star
(Phys.org)—A team of researchers with the University of North Carolina at Chapel Hill and the University of Akron has devised a method to shape shift materials into a preconditioned state at a preprogrammed time. They have published a paper in the journal Nature Communications describing their materials and how they can be programmed and have created a video that shows the shape shifting in action. 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. Sequential ‘blooming’ of an artificial flower, which has been assembled from individually programed petals Supplementary Movie 4. Credit: Sheiko et al. Nature Communications Heat, light stimulate self-assembly: Researchers develop shape-changing ‘smart’ material Creating materials that can change shape under given conditions would be useful in a variety of applications, including space-based constructions, microstructures for delivering medications inside the human body or monitoring abilities. Up until now, however, such constructs have relied on an external stimulus to cause the change to occur, e.g. heat, light or even a change in pH level. In this new effort, the researchers have developed a material that can be caused to initiate shape shifting at a preprogrammed time.The team created their materials by making use of two different types of chemical bonds—dynamic and permanent—using hydrogel polymers that were similar to human cartilage. The dynamic bonds control the change in state while the permanent bonds control the final state of the material after it has shape shifted. The energy that is stored due to folding is what ultimately drives the transformation. Preprogramming is done by adjusting the parameters that define the bonds such as location, strength and number. The team reports that they can control the shape shifting to within hours, minutes or even seconds.The team also reports that they created many objects to test the materials. To demonstrate the effectiveness of their approach, they created a flower that blooms over time with different parts opening after others, just as occurs in nature. They filmed the action, speeded it up, and then posted a video of the results on YouTube. The team also notes that they believe such material could be used to deliver drugs in the body in a novel way—they would be transported to the site where they are needed and delivered when the material shape shifted, allowing the drug to be released. © 2016 Phys.org Journal information: Nature Communications Citation: Preprogramming materials to shape shift at a given time (w/ video) (2016, September 28) retrieved 18 August 2019 from https://phys.org/news/2016-09-preprogramming-materials-shift.html Explore further More information: Xiaobo Hu et al. Programming temporal shapeshifting, Nature Communications (2016). DOI: 10.1038/ncomms12919AbstractShapeshifting enables a wide range of engineering and biomedical applications, but until now transformations have required external triggers. This prerequisite limits viability in closed or inert systems and puts forward the challenge of developing materials with intrinsically encoded shape evolution. Herein we demonstrate programmable shape-memory materials that perform a sequence of encoded actuations under constant environment conditions without using an external trigger. We employ dual network hydrogels: in the first network, covalent crosslinks are introduced for elastic energy storage, and in the second one, temporary hydrogen-bonds regulate the energy release rate. Through strain-induced and time-dependent reorganization of the reversible hydrogen-bonds, this dual network allows for encoding both the rate and pathway of shape transformations on timescales from seconds to hours. This generic mechanism for programming trigger-free shapeshifting opens new ways to design autonomous actuators, drug-release systems and active implants.
Kolkata: Police arrested a real estate developer following an interrogation at Bidhannagar North police station in connection with a case where an allegation of cheating an elderly person has cropped up.Police said one Suchitra Bakshi had lodged a complaint against real estate developer Biswadeep Chakraborty. She lodged the complaint alleging that she was cheated by Chakraborty, who had engaged into an agreement with her to develop a multi-storeyed residential building on her plot in Salt Lake. She claimed that she was supposed to get Rs 70 lakh from the developer and also a floor of the building along with a parking space as per the agreement. Also Read – Heavy rain hits traffic, flightsShe claimed that the real estate developer had given them a total of Rs 14 lakh in phases and they had even shifted to a rented house. Rent of three months were also given by the developer in advance. But the situation turned worse when the rent was no more paid and the landlord didn’t allow the complainant to stay anymore at the rented house. The complainant had repeatedly attempted to seek attention of the real estate developer. But it was of no help, she alleged. Finally, she shifted to another rented house at Lake Town and lodged a complaint with the police. Police initiated a probe in this connection and initially detained him for interrogation. He failed to give any clarification to many questions of the investigating officers for which he was arrested.
Kolkata: In a tragic incident, a promising cricketer was killed by lightening in the city while two separate road accidents claimed two lives and injured seven others in the districts.Debabrata Pal (21), a resident of Hooghly’s Srerampur was returning home after practicing cricket on Vivekananda Park ground at around 1.40 pm when the accident took place. According to local sources, the victim stopped his practice after it started raining. When he was walking along the lane, lightning struck him. He was later taken to a nearby hospital where doctors pronounced him brought dead. The victim used to play cricket for Calcutta Cricket Academy. Also Read – Heavy rain hits traffic, flightsRoad accident claimed lives of two children who were returning home on a bicycle along with their parents. The deceased have been identified as Ganesh and Riya Bhunia. Their parents have also received injuries. It took place at Radhanagar village under Bishnupur police station in Bankura on Saturday night when a speeding truck hit the bicycle. The driver of the truck fled the spot leaving the vehicle at the spot. Locals took the injured victims to Radhanagar Gramin hospital where the children were declared brought dead while their parents are undergoing treatment in the hospital. Police seized the truck and are conducting raids to nab the driver. In another accident, five persons were injured when the car they were travelling in overturned on National Highway 6 near Manasatala at Uluberai. According to police, there were three youth and a woman in the car.
Kolkata: Don’t buy Hilsa fingerlings to save the species, a call made by Chief Minister Mamata Banerjee will be the theme of the Hilsa festival organised by Baro Pally Jadavpur.It may be mentioned that the Chief Minister had said over and again not to buy Hilsa fingerlings and directed the state Fisheries department to conduct raids in markets to ensure that they are not sold.Baro Pally Jadavpur is using the festival as a platform to create awareness among the locals. The club looks after 1,200 fishermen of the Sunderbans who go to the deep sea to catch Hilsa. The club has given them medical insurance and also looks after their children. The honey collectors of the Sunderbans who are often attacked by tigers are given assistance by this club. Also Read – Rain batters Kolkata, cripples normal life”We organise the festival to create social awareness about the fishermen who take life risks to catch Hilsa. Also, selling and buying of Hilsa fingerlings are banned and we have launched an intense campaign on the issue,” said Rahul Ghosh, secretary of Ilish Utsav Committee.The committee will felicitate Utpal Ghosh, secretary of Binaynagar Bengali Senior Secondary School, New Delhi, where the medium of instruction is Bengali. The higher secondary school starts from nursery level.Sudip Roy, a sergeant of the Kolkata Police, whose left leg had to be amputated after being hit by a lorry while on duty had lost all hope. Artificial limbs were installed and he recently joined his duties. He will be felicitated by the committee, said Pradip Chowdhury, chairman of the committee.
Kolkata: Two BJP supporters were arrested on Wednesday from Howrah, for damaging state-run buses and intervention in police work on September 26, when the party had called a 12 hour bandh to protest against the killing of two students in Islampur in police firing.With the arrest of the two BJP supporters, the total number of arrests relating to bandh related issues in the district rose to 8.The BJP supporters had set fire to three state-run buses and caused extensive damage to 8 other buses on the day of the bandh.Acting on a tip-off, police raided the houses of the two BJP supporters on Wednesday afternoon and arrested them. They were produced before the court and have been remanded to police custody for three days.The arrested BJP workers had also stopped police from discharging their duties.On Brabourne Road, BJP supporters set fire to a state-run bus. Some buses were also damaged in North Bengal. In Howrah, BJP workers pelted stones at a taxi that was carrying a patient to SSKM Hospital. They forced the driver to stop the vehicle and forced the patient to get down.In Islampur also, the police arrested a local BJP leader for threatening the police and taking out a procession without police permission.
At the time India played a pivotal role in helping Korea to get out of that tumultous situation. With the communist invasion of South Korea in 1950, the UN sent out a call to the free world for assistance. India decided not to get involved militarily but contributed a medical unit, the 60 Parachute Field Ambulance (60 PFA) which served in Korea for a total of four years.Acknowledging the contribution made by India during the Korean war, an exhibition at the Embassy of the Republic of Korea took place in the national Capital on Tuesday showcasing sixty years of close association with India. It showcased 23 photographs, 2 silver flutes and a bugle, which was used by Korean War Veterans during the Korean War in 1950. The occasion was graced by the presence of Cho Hyun ,ambassador of the Republic of Korea to India, Vikram Doraiswami – ambassador of India to Korea and was joined by the Head of the Korean War Veterans and officials of the Indian army. Also Read – ‘Playing Jojo was emotionally exhausting’Throwing light on India’s role in the Korean war, Cho Hyun, said, “Korea was fortunate to have India, the source of an ancient and noble civilization, as a friend during the war. Without India’s support Korea would not have become what it is today”. Seeing the importance of these images for Korea, the Indian parachute medical unit donated all the showcased items to the Korean Government. This was a very proud moment for the both countries. The future of India-South Korea bilateral relations looks promising. Apart from deepening economic and security, defence cooperation, there is a new political understanding between the two countries. Also Read – Leslie doing new comedy special with NetflixBoth the countries have discovered a commonality of strategic interests, experience and belief that are strengthening bilateral ties sharing a somewhat similar historical experience. The strategic history of India with the Northeast Asia remained disjointed for almost four decades since the end of the war despite the important role played by the 60th Parachute Field Military Ambulance Platoon. A mobile army surgical hospital that treated more than half of the wounded soldiers, an average of 250-300 civilians a day, during the UN operations in late 1951, is still remembered with a lot of admiration and appreciation in South Korea.
When fashion gets the color of culture, the outcome is always something new from the maker’s end. In same way ‘Indypindy’ has brought fashion items dedicated towards women but it also presents a fusion of international and local cultural extravaganzas. ‘Indypindy’ organised a two-day fashion couture event recently at LGF Navjeevan Vihar in the national Capital. It houses some of the best designers in their domains to deliver top notch and state-of-the-art products whether it is a saree, skirt or a clutch! The event witnessed the gracious presence of Sandeep Marwah, Director AAFT who encouraged the budding designers for adapting the idea of ‘Indypindy’ which focuses on the concept of ‘Make in India’. Also Read – Add new books to your shelfThe event was also graced by the presence of Dr Shalini Sharma who imparted solutions at her special sessions on palmistry mixed with numerology to give the visitors simple solutions to their life issues. ‘IndyPindy’ is a brand name inspired from two words “Indian” and “Pind” which means an Indian village. As the name suggests it is a group of Indian nomad designers who travel across the country and showcase their designs and unique collection to the diverse audience present in each part of India.The designers take up the designs from the rural and local area reflecting the native culture and fashion of the place and driving it to a national and international platform give rural handicrafts and designs complete exposure.