Time scale established for proton transfer

first_img Explore further Nagasaka is an assistant professor at the Institute for Molecular Science in Okazaki, Japan, and has belonged to the University of Tokyo, where until last year he worked as a doctoral student with Kondoh, Amemiya, Ohta and Iwasawa. Their work focuses on establishing the time scale of proton transfer between water (H2O) and hydroxyl (OH) on a platinum (Pt) surface. Their work appears in Physical Review Letters: “Proton Transfer in a Two-Dimensional Hydrogen-Bonding Network: Water and Hydroxyl on a Pt(111) Surface.”“This is a two-dimensional bonding network,” Nagasaka explains. “It becomes a model system to study proton speed, and to give us a time scale.”In the experiment, the team used laser-induced thermal desorption in order to prepare a specially patterned honeycomb arrangement of H2O and OH. Laser-induced thermal desorption is a method that allows for physical separation, usually from solids. A laser is used to provide heat in such a way as to prepare the special arrangement of the water and hydroxyl on the platinum surface.At the same time, the evolution of the H2O and OH distribution was observed with the help of microscale x-ray photoelectron sprectroscopy (micro-XPS). This process is used to measure elemental composition on a tiny scale, allowing the team in Japan to record the process. After analyzing the results, a diffusion equation was used to determine that direct proton transfer had taken place.“This is very basic science,” Nagasaka explains. “Proton transfer is very important in physics, chemistry and even biology. But we don’t have a very good understanding of how the mechanism works. This is an important result, and a first step in studying how to control different reactions.”Nagasaka says that it has been difficult to determine reaction rates, and this can impact different experiments in a variety fields, especially those that concern surface materials. “We were able to determine the speed on the nano time scale using our new method,” he points out. “This is first result like this, and there is a possibility to apply it to other processes.” He’s not sure, but he thinks that maybe the method of combining laser-induced thermal desorption with micro-XPS could be used to help study reaction rates in fusion.Most of Nagasaka’s work focuses on surface chemistry – the study of how different molecules and atoms react on surfaces. The field of surface chemistry has grown in recent years to encompass electronics, fuel production (including renewable fuels) and other applications, such as artificial fertilizers. Understanding proton transfer could open up new avenues of study and lead to innovation in a number of fields, as well as in various scientific disciplines.“This is really a model system,” Nagasaka explains. “During the next five years we will do further study.”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 the past,” Masanari Nagasaka tells PhysOrg.com, “we only knew that proton transfer was a fast process. Now we are able to determine the speed of proton transfer. This is a step in understanding the mechanism of proton transfer, which is very important in many fields.” 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.center_img Citation: Time scale established for proton transfer (2008, March 20) retrieved 18 August 2019 from https://phys.org/news/2008-03-scale-proton.html Earth’s core has been leaking for billions of yearslast_img read more

Google looking to make driverless cars legal in Nevada

center_img © 2010 PhysOrg.com It was just last March that Google announced to the world that it had been racing autonomous cars around on rooftop parking lots and then just seven months later that it had been testing those cars on California roads; news that both made headlines and bolstered Google’s image as one of the more innovative companies operating today. Now comes news that Google is ready to tackle the sticky problem of allowing such cars to drive legally on roads, an issue no doubt that cropped up in the wake of its earlier announcements.It’s not exactly clear why Google chose Nevada for its first push at legalizing what it’s been doing already; though there are theories, such as the fact that the giant Consumer Electronics Show (CES) just happens to be held in Las Vegas each year, or maybe it’s because Nevada has a history of allowing things that other states don’t; prostitution being the most infamous example, of course. Or it might be the fact that Nevada has a lot of roads that have very little traffic in very out-of-the-way places and thus could test its vehicles on public roads without much oversight. (PhysOrg.com) — In an unexpected move, Google, the wily search giant with loads of ambition and enough spare cash to enable it to dabble in technologies that appear to have nothing to do with its core business, has hired lobbyist David Goldwater to represent the company in its push to legalize the running of autonomous vehicles on Nevada roads; this comes less than a year after announcing that it had been running live tests of its self-driving vehicles on California roads.last_img read more

Pioneer previews integrated floating image display technology

first_imgThe Pioneer FV-01 Floating Vision system. FV-01 system The system makes use of a 3D module that has an LCD module mounted on the back. The system then uses a specially designed 3D lens, mounted in the front, which allows the image to appear as if it is floating in space. Since it only relies on one projection, and not the traditional right and left eye perspectives of older 3D systems the screen can project a clear image from a variety of angles and without the use of glasses. At the Embedded Systems Expo demonstration the in-car navigation system was paired with multiple touch panel displays. The system allows a user to select an object on the touch screen panel the same way that you would with most navigation systems. Then once a hand is swiped over the Floating Vision display the image of the object that the user selected is projected into the 3D display map. This system is similar to the FV-01, a PC connection system that creates a floating 3D display, currently being sold by Pioneer. The company hopes to move from the USB connections of the current systems to integrated systems in the future with the use of the Floating Vision system. © 2010 PhysOrg.com Explore further Japanese Researchers Develop Portable 3D Display System Citation: Pioneer previews integrated floating image display technology (2011, May 26) retrieved 18 August 2019 from https://phys.org/news/2011-05-previews-image-technology.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — Pioneer has recently conducted a demonstration of its floating image display technology, which is being called Floating Vision, that allows for a small sized 3D floating screen to be projected into spaces like the dashboard of a car. The system, which was shown off at the Embedded Systems Expo, uses a set of infrared sensors that allow this projected screen to be used in a manner similar to that of the current touch screen systems in use, in a limited capacity at the present moment. The system was demonstrated both in a car, and in the context of a customer service scenario. last_img read more

Study shows fairy wrasses perceive and respond to their own deep red

first_img Journal information: Proceedings of the Royal Society B Fluorescence characterization of C. solorensis. (a) Male fish illuminated with broad-spectrum white light; (b) same individual under monochromatic blue illumination. (c) Excitation (dashed line) and emission (solid line) spectra of opercular scales. Credit: Proceedings of the Royal Society B, doi: 10.1098/rspb.2014.0787 Citation: Study shows fairy wrasses perceive and respond to their own deep red fluorescent coloration (2014, May 28) retrieved 18 August 2019 from https://phys.org/news/2014-05-fairy-wrasses-deep-red-fluorescent.html Researchers find blind fish use novel type of navigational aid 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: Fairy wrasses perceive and respond to their deep red fluorescent coloration, Proceedings of the Royal Society B, Published 28 May 2014 DOI: 10.1098/rspb.2014.0787AbstractFluorescence enables the display of wavelengths that are absent in the natural environment, offering the potential to generate conspicuous colour contrasts. The marine fairy wrasse Cirrhilabrus solorensis displays prominent fluorescence in the deep red range (650–700 nm). This is remarkable because marine fishes are generally assumed to have poor sensitivity in this part of the visual spectrum. Here, we investigated whether C. solorensis males can perceive the fluorescence featured in this species by testing whether the presence or absence of red fluorescence affects male–male interactions under exclusive blue illumination. Given that males respond aggressively towards mirror-image stimuli, we quantified agonistic behaviour against mirrors covered with filters that did or did not absorb long (i.e. red) wavelengths. Males showed significantly fewer agonistic responses when their fluorescent signal was masked, independent of brightness differences. Our results unequivocally show that C. solorensis can see its deep red fluorescent coloration and that this pattern affects male–male interactions. This is the first study to demonstrate that deep red fluorescent body coloration can be perceived and has behavioural significance in a reef fish.center_img © 2014 Phys.org Explore further Most fish that live in deep ocean water are blue, which is generally thought to be because blue light is able to pass through the water above and other colors are not. That makes it almost impossible for those that reside in such deep waters to see any other color, thus there would be no point in being any other color. No point that is, unless you’re a fish that can not only produce a fluorescent color, but are able to see it as well. That appears to be the case with fairy wrasses (who live at depths of 30 to 200 feet)—the tops of their heads are colored fluorescent red and parts of their foreheads are yellow. Such coloring must have a purpose, the researchers surmised, likely to ward off rivals or predators or to attract a mate—the reasons behind most such coloring in fish that live closer to the surface. To find answers to their questions, the trio ventured to Indonesia, where the fish reside.First they conducted a field study, watching the fish in their native environment. Then, they bought some specimens and put them in water tanks outfitted with mirrors. The mirrors were so the fish could see themselves, obviously, which being creatures with small brains, would naturally assume were other male fish. Upon seeing themselves in all their full colored glory, the males attacked. When filters were put in place that allowed the fish to see themselves without the fluorescent coloring, however, the reaction was much less pronounced, proving that the fish were able to see the coloring and had a tendency to react to it. The study is the first to demonstrate that deep red fluorescent coloration can be seen (and responded to) by a reef fish. The researchers next plan to test females of the species to determine if male coloring is also meant to attract a mate. (Phys.org) —A trio of researchers with the University of Tübingen in Germany has found that the fairy wrasse (Cirrhilabrus solorensis) is able to perceive its own deep red fluorescent coloring and responds to it in aggressive ways. In their paper published in Proceedings of the Royal Society B: Biological Sciences, Tobias Gerlach, Dennis Sprenger and Nico Michiels describe field and lab studies they conducted that appear to prove that the fish is able to see fluorescent colors.last_img read more

Proposed diamond maser could operate at room temperature

first_img(Phys.org)—Before there were lasers, there were masers—devices that operate in the microwave regime and other wavelengths that are longer than those of visible light. But while the first masers were built back in the 1950s, they have failed to achieve the same commercial success as lasers due to their demanding operating conditions: gas masers require high-vacuum conditions and solid-state masers require ultracold liquid-helium temperatures (about 4 K) to operate. In a new paper published in Nature Communications, Liang Jin, et al., from The Chinese University of Hong Kong and the University of Stuttgart, have proposed a concept for a diamond maser that can operate at room temperature. With the potential to achieve a coherence time of a few minutes, the maser could pave the way for widespread applications.The biggest advantage of using diamonds is that diamonds have nitrogen-vacancy center spins that have the longest known lifetime at room temperature of any known solid-state spin, and a long spin lifetime is essential for achieving a key maser mechanism: population inversion. In population inversion, more spins exist in an excited state than in a lower-energy state, and so a long spin lifetime is required. The problem is that the spin lifetimes in most solids at room temperature are much too short—often just a few nanoseconds—to achieve useful population inversion.In contrast, the diamond spins have a lifetime of about 5 milliseconds at room temperature, making them an ideal candidate for a room-temperature maser. These spins can be rapidly pumped to their excited state with the help of a magnetic field, and even though a magnetic field may complicate the device’s experimental realization, the researchers expect that the challenge can be overcome with commercially available magnets.If the diamond maser could be realized in the future, it would be the second room-temperature solid-state maser demonstrated so far. In 2012, researchers from the UK reported in Nature the first such device, which they made out of an organic material (p-terphenyl doped with pentacene), which has a lifetime of about 0.1 microseconds—about 1/50th of that of the proposed diamond spins. Although the pentacene-based device marked an important milestone as the first room-temperature maser ever demonstrated, its spins could not completely reach the ground state but instead existed in an intermediate, metastable state. As a result, the pentacene maser had low efficiency and could only operate in pulsed mode at a low rate. The researchers of the new study hope that the proposed diamond maser will improve in these areas, with the potential to achieve a higher stability, higher efficiency, and longer masing time. “The diamond maser can work at room temperature and in a continuous wave mode, in contrast with the pentacene maser,” coauthor Renbao Liu, Physics Professor at The Chinese University of Hong Kong, told Phys.org. “Also, the diamond material is very stable under high-power pump, which is not the case for organic materials.”If a maser can be realized with these features, it could have a variety of applications for microwave technologies, including radar and high-precision clocks. Portable, room-temperature masers could be used for ultrasensitive magnetic resonance spectroscopy to study minerals. The maser could also be used as a low-noise amplifier for space communication. “Room-temperature microwave amplifiers with a noise temperature of about 1 K can be employed to amplify microwave signals from satellites, or used in space to detect microwave signals from remote universe backgrounds,” Liu said.In the future, the researchers will work on experimentally demonstrating the maser, along with running more realistic simulations and studying the collective quantum coherence effects in the diamond spins when coupled to microwave photons. Journal information: Nature Illustration of the room-temperature diamond maser. Credit: Jin, et al. ©2015 Macmillan Publishers Limited Citation: Proposed diamond maser could operate at room temperature (2015, October 5) retrieved 18 August 2019 from https://phys.org/news/2015-10-diamond-maser-room-temperature.html MASER power comes out of the cold: Researchers demo solid-state MASER capable of operating at room temperatures 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: Liang Jin, et al. “Proposal for a room-temperature diamond maser.” Nature Communications. DOI: 10.1038/ncomms9251 © 2015 Phys.org Explore further , Nature Communicationslast_img read more

Amino acids formed from the singleelectron activation of carbon dioxide

first_img More information: Hyowon Seo et al. Photoredox activation of carbon dioxide for amino acid synthesis in continuous flow, Nature Chemistry (2016). DOI: 10.1038/nchem.2690AbstractAlthough carbon dioxide (CO2) is highly abundant, its low reactivity has limited its use in chemical synthesis. In particular, methods for carbon–carbon bond formation generally rely on two-electron mechanisms for CO2 activation and require highly activated reaction partners. Alternatively, radical pathways accessed via photoredox catalysis could provide new reactivity under milder conditions. Here we demonstrate the direct coupling of CO2 and amines via the single-electron reduction of CO2 for the photoredox-catalysed continuous flow synthesis of α-amino acids. By leveraging the advantages of utilizing gases and photochemistry in flow, a commercially available organic photoredox catalyst effects the selective α-carboxylation of amines that bear various functional groups and heterocycles. The preliminary mechanistic studies support CO2 activation and carbon–carbon bond formation via single-electron pathways, and we expect that this strategy will inspire new perspectives on using this feedstock chemical in organic synthesis. Design plan for α-carboxylation of amines with CO2. a, Carbon–carbon bond formation with CO2 has generally relied on two-electron reaction pathways with an extended π system or a strong nucleophile. Cat., catalyst. b, Single-electron reduction of carbon dioxide and its reaction with an α-amino radical to provide an α-amino acid. c, Continuous flow setup for the photoredox-catalysed synthesis of α-amino acids. The reactants were introduced via a gas-tight syringe that contained a solution of the amine substrate, base and catalyst. CO2 gas was metered into the system by a mass flow controller (MFC). These two streams were joined by a T-mixer before irradiation under an ultraviolet lamp. The pressure of CO2 is controlled by a back-pressure regulator (BPR). Credit: (c) Nature Chemistry (2016). DOI: 10.1038/nchem.2690 Hyowon Seo, Matthew H. Katcher, and Timothy F. Jamison of Massachusetts Institute of Technology have developed a continuous flow system that allows for the single-electron reduction of CO2 that combines with a variety of amines to form α-amino acids. Their methodology involves the use of a photoredox catalyst and, using their flow system, optimized reaction conditions to obtain regioselective α-amino acids in high yields. Their work appears in Nature Chemistry.The keys to this group’s procedure are the photoredox catalyst and the ability to fine-tune their reaction conditions using their continuous flow system. In determining the appropriate photoredox catalyst, Seo et al. tested para-terphenyl based on prior work by Yanagida’s group. This catalyst was attractive because it has an appropriately high reduction potential to reduce CO2.The photoredox catalyst served to remove an electron from the amine as well as to catalyze the reduction of CO2. These two radical molecules then combined to form a C-C bond at the benzylic C-H of an N-benzyl compound resulting in an α-amino acid. Additional experiments showed that this reaction worked well with a variety of amines including those that do not have a benzylic carbon.The second important aspect to this reaction mechanism is the continuous flow set up. Carbon dioxide gas is mixed with a liquid aspiration of amine and catalyst. This system allowed for the controlled flow of CO2, which in turn allowed for the controlled combination of the amine radical and the CO2 radical. Seo et al. were able to optimize the pressure and flow of CO2 to obtain maximum yields. An additional advantage to this set up was the short path length of light, which also helped control when it would activate the catalyst and prompt the redox reaction to occur.Using N-benzylpiperdine as their model reaction, Seo et al. tested their apparatus first using the reaction conditions reported by Yanagida’s group. They then optimized the conditions to eventually obtain the desired α-amino acid in 92% yield. Among their changes, they added potassium trifluoroacetate (KOCOCF3) base, which helped with yields and regioselectivity. While mechanistic studies did not reveal exactly how the base is used, Seo et al. hypothesized that it served as a salt stabilizer.Additionally, Seo et al. optimized their reaction using a UV filter. This prohibited the formation of unwanted by-products that resulted from short wave irradiation. In do this, they obtained 92% yield of the desired α-amino acid. Prior to using the UV filter, they would obtain two different regio isomers, but after the filter, they saw almost exclusive regioselectivity for the desired product (i.e., carboxylation at the benzylic position).Once they obtained the optimal reaction conditions, they then tried to make a variety of α-amino acids. Notably, all cases showed a greater than 20-to-1 regioselectivity in favor of the desired α-amino acid. Among their results, they found that N-benzylpiperdines with ortho-, meta-, and para-alkyl substitution worked well, resulting in the desired α-amino acids as did chloroarenes and a variety of amines. Amines with several types of heterocycles and fused rings tolerated the reaction conditions well. N-benzyl amines with electron poor arenes did not do as well, and neither did alcohols, ketals, or primary amines. However, masked versions of alcohols and ketals can be produced, and the reaction does tolerate 4-piperidone analogs as a possible bis-protecting group for primary amines. Also their reaction worked well when tested on a known pharmaceutical ingredient with a heterocycle and no benzylic C-H bond (ticlopidine).”Very interesting to us is the fundamental chemistry of the radical anion of carbon dioxide, which we’ve proposed as a key intermediate in this process,” says Professor Timothy Jamison. “Some of our ongoing efforts are directed toward using this enabling platform as a means toward this aim.” Citation: Amino acids formed from the single-electron activation of carbon dioxide (2017, January 12) retrieved 18 August 2019 from https://phys.org/news/2017-01-amino-acids-single-electron-carbon-dioxide.html (Phys.org)—Carbon dioxide, an abundant greenhouse gas, is very difficult to use as a carbon source for carbon-carbon bond formation. CO2 is highly stable and unreactive, requiring prohibitively difficult or toxic reagents in order to form carbon bonds. Regioselective hydroarylation of alkynes to make ortho-, para-, and meta- productscenter_img Journal information: Nature Chemistry 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. © 2017 Phys.orglast_img read more

Forgotten melodies

first_imgThe Capital hosted a night of rare and long forgotten music, a n unique experience for the city’s music lovers.  Pracheen Kala Kendra organised this musical concert  to save the dieing Indian classical music and in memory of Madan Lal Koser. Talking about the initiative of saving the long lost Indian classical music, Sajal Kausar said ‘Pracheen Kala Kendra is making an effort to make people realize that Indian classical music is the gist of Indian culture and its essence should be valued. We are heading towards preserving the cultural heritage of the country.’ Also Read – ‘Playing Jojo was emotionally exhausting’The auditorium of Shri Ram Centre for Arts witnessed centuries old musical sound based on ancient Indian traditions. Adding life to the concert were the performance given by Vishwa Mohan Bhatt and Salil Bhatt who performed a jugalbandi over mohan veena and satvik veena. They were accompanied in their act by Parameshwar Hedge, MD. Akram Khan and  Himanshu Mahat on tabla.After presenting the age old classical music to Delhi’iets Salil Bahtt said,  ‘I appreciate the attempt of the Pracheen Kala Kendra to save classical music from being extinct and is overwhelmed to be a part of this cause.’Before the concert Pandit Vishwa Mohan Bhatt and Salil Bhatt has also launched their albums East Meets West – Ecstatic Fusion of Indian Classical, Jazz and Western Percussions and Satkriti – The musical creation of Lord Shiva.last_img read more