Scientists grow solar cell components in tobacco plants

first_imgScientists are working on synthesizing solar cells from chromophore structures they produced in tobacco plants. Image credit: US Department of Agriculture. © 2010 PhysOrg.com Scientists grow insulin in tobacco plants In a recent study, scientists from UC Berkeley led by Matt Francis have demonstrated how to program tobacco plants to take advantage of the efficient way that they collect sunlight. Rather than attempt to reprogram all the cells of a mature tobacco plant, the scientists genetically engineered a virus called the tobacco mosaic virus to do the job for them. The researchers sprayed the modified virus on a crop of tobacco plants, and the virus caused the plant cells to produce lots of artificial chromophores, which turn photons from sunlight into electrons.In order for the chromophores to work, however, they must be spaced at a precise distance from one another – about two or three nanometers. A little closer or further apart, and the electric current will either be halted or the electrons will be very difficult to harvest. Thankfully, tobacco plant cells have evolved to space chromophores at this exact distance, lining them up in a long spiral hundreds of nanometers long. By exploiting this structure, the researchers could take advantage of billions of years of evolution to grow perfectly spaced strands of chromophores. “Over billions of years, evolution has established exactly the right distances between chromophores to allow them to collect and use light from the sun with unparalleled efficiency,” said Francis.Since the modified tobacco plants themselves don’t generate electricity, the researchers must harvest the plants and extract the chromophore structures. Then, the scientists can dissolve the structures in a liquid solution, and then spray the solution on a glass or plastic substrate to create a solar cell. So far, the scientists have not yet demonstrated that the resulting solar cells can turn light into electrical energy.Compared with traditional solar cells, those made from plants could have several potential advantages. For instance, they don’t require the use of toxic chemicals, they’re biodegradable, and they’re inexpensive to produce. On the other hand, bio-based solar cells would likely have a shorter lifetime than silicon solar cells.In addition to using tobacco, the researchers also demonstrated how to manipulate E. coli bacteria to produce chromophore structures. In this case, the researchers didn’t use a virus, but modified the bacteria directly. More information: Michel T. Dedeo, Karl E. Duderstadt, James M. Berger and Matthew B. Francis. “Nanoscale Protein Assemblies from a Circular Permutant of the Tobacco Mosaic Virus.” Nano Lett., 2010, 10 (1), pp 181-186. doi:10.1021/nl9032395Via: Discovery News Citation: Scientists grow solar cell components in tobacco plants (2010, January 29) retrieved 18 August 2019 from https://phys.org/news/2010-01-scientists-solar-cell-components-tobacco.html Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — Over billions of years, plants have evolved very efficient sunlight-collecting systems. Now, scientists are trying to harness the finely tuned systems in tobacco plants in order to use them as the building blocks of solar cells. Scientists predict that the technique could lead to the production of inexpensive, biodegradable solar cells.last_img read more

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Donated Chinese bamboo strips turn out to be ancient multiplication table

first_img © 2014 Phys.org Citation: Donated Chinese bamboo strips turn out to be ancient multiplication table (2014, January 9) retrieved 18 August 2019 from https://phys.org/news/2014-01-donated-chinese-bamboo-ancient-multiplication_1.html The bamboo strips were part of a much larger collection of very old and partially decomposed bamboo strips, all of which had writing on the back. Recently, the researchers separated out the strips that had numbers on the back instead of characters representing letters. Figuring out what the numbers meant was a time-consuming process as they were in random order—the string that once bound them together had decayed thousands of years before. The time during which they were created corresponds to a period just before the Qin Dynasty, when what is now known as China was still divided into several warring states. Each strip is approximately 20 inches long and slightly less than half an inch wide, and the collection is believed to have been part of a set of artifacts retrieved from an ancient tomb which was subsequently lost to illegal trafficking. The person that donated the collection to university had bought it at a market in Hong Kong.Lining the strips in the right way reveals a table very much like a modern multiplication table—numbers across the sides and tops are used as multiplicands, their intersection points mark the result. Interestingly, the table also allows for multiplying partial numbers between 0.5 and 99.5, though the process requires converting equations into sums first.The researchers believe the multiplication table was likely used to measure land area, or to predict crop yields. They note the table can also be used to solve division problems, but doubt the people using them had learned of such math at the time. Prior to the new discovery, the oldest known multiplying device found in China was a table dated back to a period a couple of hundred years later than this new table, and it was considerably less useful. The new bamboo table represents a level of mathematical sophistication unheard of for the time, meaning historians will have to revise their estimates of the skill levels of the people that invented the table. Credit: Research and Conservation Centre for Excavated Text/Tsinghua Univ. via Nature. 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. Journal information: Naturecenter_img (Phys.org) —Researchers at Tsinghua University in China are reporting that a subset of bamboo strips donated to the university five years ago has been found to make up an ancient Chinese multiplication table. Dated back to 2,300 years ago (circa 305 B.C.), the table represents the oldest-known such device that computes in base 10—ancient Babylonian tables dating back 4000 years were base 60. NOAA reports discovery of table coral, Acropora cytherea, off O’ahu Explore further More information: via Naturelast_img read more

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No ink required paper can be printed with light

first_img Various samples of the light-printable paper. Credit: Wang et al. ©2017 American Chemical Society Rewritable material could help reduce paper waste The researchers, Wenshou Wang and coauthors at Shandong University in China; the University of California, Riverside; and Lawrence Berkeley National Laboratory, have published a paper on the light-printable rewritable paper in a recent issue of Nano Letters.”The greatest significance of our work is the development of a new class of solid-state photoreversible color-switching system to produce an ink-free light-printable rewritable paper that has the same feel and appearance as conventional paper, but can be printed and erased repeatedly without the need for additional ink,” Yadong Yin, Chemistry Professor at the University of California, Riverside, told Phys.org. “Our work is believed to have enormous economic and environmental merits to modern society.”Currently, paper production and disposal have a large negative impact on the environment: paper production is a leading source of industrial pollution, discarded paper is a major component (approximately 40%) of landfills, and even recycling paper contributes to pollution due to the process of ink removal. There is also the issue of deforestation: in the US, about one-third of all harvested trees are used for paper and cardboard production.Working to address these problems, researchers have been investigating alternatives to disposable paper. One possibility is to take advantage of the color-switching ability of certain chemicals when exposed to light, although in the past this approach has faced challenges in terms of stability, limited reversibility, high cost, toxicity, and difficulty in applying the coating to ordinary porous paper.The light-printable paper developed in the new study improves in all of these areas, bringing the technology closer to applications, which could include any medium on which information is printed and needed for only a short time.”We believe the rewritable paper has many practical applications involving temporary information recording and reading, such as newspapers, magazines, posters, notepads, writing easels, product life indicators, oxygen sensors, and rewritable labels for various applications,” Yin said. When the Prussian blue and TiO2 nanoparticles are evenly mixed and coated onto paper, the plain unprinted paper appears solid blue. To print text or images, the paper is exposed to UV light, which photoexcites the TiO2 nanoparticles. These nanoparticles then release electrons that are picked up by the adjacent Prussian blue nanoparticles, which turn from blue to colorless. Since it’s easier to read blue text on a colorless background than colorless text on a blue background, it’s the background rather than the text that is typically printed by light, turning colorless (although the paper can also be “reverse-printed” to show colorless text on a blue background). Different colors besides blue can also be achieved by using Prussian blue analogues of various colors.Once printed, the paper retains its configuration for at least five days with high (5-µm) resolution, and then slowly fades back to solid blue through oxidation under ambient conditions. To erase the paper more quickly, the paper can be heated for about 10 minutes to return it to its solid blue state. The researchers predict that light-printable paper will be inexpensive when produced on a commercial scale.”The light-printable paper is indeed cost-competitive with conventional paper,” Yin said. “The coating materials are inexpensive, and the production cost is also expected to be low as the coating can be applied to the surface of conventional paper by simple processes such as soaking or spraying. The printing process is also more cost-effective than the conventional one as no inks are needed. Most importantly, the light-printable paper can be reused over 80 times, which significantly reduces the overall cost.”Future plans focus on bringing the technology closer to practical use.”Our immediate next step is to construct a laser printer to work with this rewritable paper to enable fast printing,” Yin said. “We will also look into effective methods for realizing full-color printing.” Citation: No ink required: paper can be printed with light (2017, February 2) retrieved 18 August 2019 from https://phys.org/news/2017-02-ink-required-paper.html Journal information: Nano Letters Explore further (Phys.org)—In an effort to curb the adverse environmental impacts of paper production, researchers in a new study have developed a light-printable paper—paper that can be printed with UV light, erased by heating to 120 °C (250 °F), and rewritten more than 80 times. The secret to printing with light lies in the color-changing chemistry of nanoparticles, a thin coating of which can be easily applied to conventional paper to transform it into the light-printable version. © 2017 Phys.org Light-printable rewritable paper showing a quote by Richard Feynman. Credit: Wang et al. ©2017 American Chemical Society The new coating consists of two types of nanoparticles: those made of Prussian blue, which is a common inexpensive, nontoxic blue pigment that turns colorless when it gains electrons; and titanium dioxide (TiO2), a photocatalytic material that accelerates chemical reactions upon UV light exposure. More information: Wenshou Wang et al. “Photocatalytic Color Switching of Transition Metal Hexacyanometalate Nanoparticles for High-Performance Light-Printable Rewritable Paper.” Nano Letters. DOI: 10.1021/acs.nanolett.6b03909 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.last_img read more

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Evidence that humans prefer genetically dissimilar partners based on scent

first_img © 2019 Science X Network Explore further Prior research has shown that animals, including humans, are more successful from a genetic perspective when they mate with a partner that is genetically dissimilar in key ways. One of those differences is the makeup of their MHC—a cluster of genes that plays an important role in immune function. When two people with dissimilar clusters mate, their offspring gain the benefits of both parents. In recent years, medical researchers have suspected that people are able to “sense” the makeup of a potential mate’s MHC, and that people tend to find those with dissimilarities more attractive. It was assumed that if this were the case, that the olfactory system was responsible. The researchers with this new effort note that several studies have been conducted that were designed to determine if such theories were correct, but the results have varied widely. To find out once and for all, they conducted a larger, more thorough study.The work involved analyzing data from the Database of Genotypes and Phenotypes managed by NIH. The researchers report that they were able to use genome-wide data from over 800 couples living in Europe and the Middle East (Israel)—more specifically, they were able to see how similar their MHCs were.The researchers report that on average, the MHCs between couples in Europe were dissimilar—more so than could be accounted for by randomness. They also noted that such differences were the most pronounced in couples living in the Netherlands. But they also report that they found no such degree of dissimilarity for couples living in Israel.The researchers suggest their findings provide strong evidence of a human ability to smell MHC in other humans and to prefer mates with dissimilarities. They suggest such a preference can be overridden by cultural practices, however, such as those found in Israel, where mate choice is limited due to social standing or family practices. Journal information: Proceedings of the Royal Society B Credit: CC0 Public Domain Opposites attract — how genetics influences humans to choose their matescenter_img A team of researchers at Université Paris Diderot has found evidence that suggests humans are able to detect via smell which partners are genetically preferable. In their paper published in Proceedings of the Royal Society B, the group describes their study of the major histocompatibility complex (MHC) in people, and the ability to detect it via smell. More information: Claire Dandine-Roulland et al. Genomic evidence for MHC disassortative mating in humans, Proceedings of the Royal Society B: Biological Sciences (2019). DOI: 10.1098/rspb.2018.2664 Citation: Evidence that humans prefer genetically dissimilar partners based on scent (2019, March 20) retrieved 18 August 2019 from https://phys.org/news/2019-03-evidence-humans-genetically-dissimilar-partners.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.last_img read more

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To ace your PhD program interviews prepare to answer—and ask—these key questions

first_imgGrad school interviews—in which aspiring graduate students meet with prospective advisers, colleagues, and other students—are opportunities to connect, engage in scientific conversations, and get a hands-on feel for the graduate programs and broader communities. To make the most of them, you need to prepare in advance so that you can confidently and thoughtfully answer questions from faculty and department members who are deciding whether they want to invite you to join them. You should also ask your own questions to figure out whether the program is right for you. You’ve made it to the last step of the Ph.D. application process: the interview. Congratulations! But amid the excitement and butterflies, don’t neglect the crucial next step: preparation. To get you started, here are 10 common questions to prepare for. Read the whole story: Sciencelast_img read more

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Suu Kyis second time round

first_imgThe Indian Institute of Advanced Studies (IIAS), a research institution in Shimla, has published another edition of Myanmar’s pro-democracy icon Aung San Suu Kyi, the institute’s official said on Friday. ‘The second edition of Suu Kyi’s book Burma and India: Some Aspects of Intellectual Life under Colonialism has been brought out as a paperback edition and is priced at Rs 195,’  IIAS director Peter Ronald Desouza said in a statement. The bookis based on the manuscript Suu Kyi submitted after completion of her fellowship at the IIAS in 1987. The book, first published in 1990, is about comparative study of intellectual life under colonialism in the two countries. It describes the varying responses of India and Burma during British colonialism, responses which reflect the changing social structure and character of the two societies. It also discusses the Buddhist influence from India on Burma and the inability of Burmese society to resist the colonial onslaught in contrast to India, which developed a more substantial response. The opposition leader of Myanmar stayed at the IIAS with her husband Michael Aris, who was also a fellow, and their two sons. ‘It was through the ambassador of India to Burma that Suu Kyi could be sent the re-typed and proof-read version of her book to make the necessary changes, which she did,’ Desouza said. ‘She chose the cover design,’ he added. On the request of Suu Kyi, he said, IIAS would send some copies of the book to public libraries and universities across India. The IIAS is a premier advanced research institution in the field of humanities and social sciences.last_img read more

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Con Banega Crorepati

first_imgIt is not everyday that you see Dilliwallahs jostle to take a look at books. And buy them by the dozen. The Book Fair has been going mostly empty. But if you had been going to Dilli Haat over the last weekend, you would see how the place has completely transformed. All thanks to the Third Annual Comic Con. Every Delhiite worth his Diamond Comics came along. If not to buy books, to browse through them. If not to browse, then pick up merchandise. And if for nothing else, then to get themselves clicked with the quirky banners and with men and women who decided to give themselves a fun makeover. Also Read – ‘Playing Jojo was emotionally exhausting’Of course Comic Con is about comics. But it is as much about the merchandise, some of which you will get only at Comic Con which makes them all the more attractive for the funk-loving youngsters. And funky they all are. Superkudi, that hit theme of the last edition of Comic Con, has given way to Supermummy this year. So apart from banners, you could also pick up Supermummy tees, posters, wall clocks, cushions and even mugs. The ‘Wonder Bai’, or the ubiquitous Indian maid, was another favourite. Also Read – Leslie doing new comedy special with NetflixBut what most people were seen jostling for (and some even went back disappointed since most stalls had run out of sizes) were the Superman and Batman tees. While some were the more regular ones, there were others which had been fun slogans. The Bangalore-based Hysteria, was seen doing brisk business with their badges, posters, tees, art prints and more. So much so, that you actually had to queue up to see their poster catalogue. While the now well-known Chumbak (every girl worth her auto raja boxers have heard of them) has a stall, we found the lesser known ones doing brisk business. The merchandise was similar — tees, mugs, quirky posters, calendars and even toys of comic characters — but each added their own quirky take to them. Want to voice an opinion? Wear it on the tee. That was the USP of the Wear Your Opinion stall. A stall which stocked Harry Potter merchandise, was also a crowd favourite.last_img read more

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Indias little Poland

first_imgThis is a story of a long ago. When World War II left Poland ravaged and thousands of Polish people homeless, about 1000 children from war-torn, occupied Poland and Soviet prison camps in Stalin’s Siberia, travelled all the way to India, where Jam Sahib, Digvijaysinhji Ranjitsinhji Jadeja of Nawanagar, nephew of famous Indian cricketer Ranjitsinhji Vibhaji of  the Jadeja clan, a princely state in the Kathiawar Peninsula, took personal risks to make arrangements at a time when the world was at war and India was struggling for its independence. He built a camp for them in a place called Balachadi beside his summer palace, 25 km from his capital city Jamnagar. Also Read – ‘Playing Jojo was emotionally exhausting’The children stayed in the camp for four years (1942 to 1946), picking up pieces of their lives, making happy memories till they got to reunite with their family and friends when Polish history reached peaceful times.After years, documentary film maker, Anu Radha and Sumit Osmand Shaw have got The Survivors of Balachadi, as they like to call themselves, together, to make a heart-touching piece of narrative A Little Poland in India. The 52-miute film has been co-produced between the governments of India and Poland under audio-visual agreement between both countries; co-produced by Doordarshan, Government of Gujarat and National Audiovisual Institute and TVP (Telewizja Polska) from Poland.  Also Read – Leslie doing new comedy special with NetflixThe script and the research is by Anu Radha. This fragment of Indo-Polish history is a heartening chapter on a rare humane endeavour at times of war. Survivors of this chapter, who are featured in the documentary, remember their time in Balachadi fondly holding Jam Saheb, who they called Bapu, in high esteem. Infact, Poland has a school and a street named after Jam Saheb.The film was officially launched in the Capital in the presence of delegates, the directors and one of the survivors of Balachadi, Wieslaw Stypula, who shared his amazing story. A Little Poland in India will be telecast on 10 Nov (3:00 pm) and on the 11 November (7:30 am) on DD National. Make sure you catch it.last_img read more

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Acting up a perfect wedding

first_imgThus they call it the laddu either already savoured or still to be relished. Based around a similar idea, the play titled Perfect Wedding teaches one what not to do on his/her wedding day. It imparts knowledge of all the dos and donts for your wedding day.Presented by Saanjha Sapnaa and directed by Dushyant Babbar, the play is a romantic comedy based on an original script. The plot goes like- A man wakes up on his wedding morning in the hotel’s bridal suite with a naked woman he doesn’t know. Chaos ensues and a touching love story too. It is full of snappy dialogues, slapstick humor and blurry maze of plot twists which turn into a cheery evening of laughs and good feeling. Also Read – ‘Playing Jojo was emotionally exhausting”The play follows an error of comedy concept. Where in, the couple who was brought together to get married eventually get married to different people. It took me almost a month to conceptualise and execute the play as one of the major challenge was to find good and steady actors,’ rues Dushyant.’The one hour 20 minutes long play constitutes of playing with live properties where in the dimensions of the room set up on the stage is changed via connecting doors. This particular element is quite integral to the performance,’ says Dushyant. Witness this Perfect Wedding with full fun and entertainment on the Delhi stage.WHEN: 16 and 17 November, 6 pm and 7.30 pmWHERE: Akshara Theatre, Baba Kharak Singh Marglast_img read more

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Chokhani murder case Kishan Yadav acquitted of all charges

first_imgKolkata: The Alipore Court on Friday acquitted domestic help Kishan Yadav in connection with the murder of 54-year-old Usha Chokhani on March 16, 2008. The elderly lady, who used to live alone in her apartment at Mandevilla Gardens under Gariahat police station area, was found murdered with a pair of scissors piercing her throat and a deep wound on her neck.”After nine years of prolonged custody trial, 17th Additional District and Session Judge Subhasish Ghosal of Alipore Judges Court acquitted Yadav of all charges as police could not produce enough evidence to prove hi involvement in the crime,” Subhamoy Samaddar, the counsel for Yadav said. Also Read – Heavy rain hits traffic, flightsThere were as many as 31 witnesses who had deposed before the court during the trial. The anti homicide squad of the detective department of Kolkata Police had arrested Yadav in January 2009 nearly a year after the murder of the victim from Bengaluru. He had been in judicial custody since March 2009 and was not granted bail even for once.The sleuths pleaded before the court that Chokhani’s murder was ‘for gain’, however, the only thing that went missing from the apartment was a piece of gold earring. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedA watch, a ring and an earring were found intact on Usha’s body when police recovered it from the drawing room of her third-floored apartment. Sammadar, counsel for the accused pleaded before the court that the elderly lady’s was killed due to family dispute. “She lived alone while her two sons, Bharat and Nikhil, lived with their father Atmaram Chokhani in Ballygunge Place. The lady was looked after by a number of domestic helps. Moreover, nothing went missing from the house. The earring that was primarily found missing was also recovered from the apartment itself during the course of investigation. There were as many as 26 injury marks on the body that makes it clear that it was an act of vengeance and not for gain,” he reasoned. Her daughter Ruchi Sabetia lives in Delhi. It may be mentioned that the victim lady had hired Kishan, a resident of Banka in Bihar, only 10 days before the murder on the recommendation of an employee of a neighbourhood tea stall.last_img read more

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