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Month: August 2019

Understanding light at the nanoscale a nanosized doubleslit experiment

first_imgExperimental configuration of the SPP double-slit experiment. SPPs excite the polariton modes on the metal waveguides (“slits”). The probe taps into the SPP waves and scatters the light toward a photodetector. Image credit: Rashid Zia and Mark Brongersma. ©2007 Nature Publishing Group. 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. PSTM image of SPP polariton interference. Image credit: Rashid Zia and Mark Brongersma. ©2007 Nature Publishing Group. Recently, Stanford University researchers Rashid Zia (now with Brown University) and Mark Brongersma have investigated light on the nanoscale with an adaptation of one of the most familiar optics tests: the double-slit experiment. The test described the propagation, interference, diffraction, and a possible diffraction limit of a type of electromagnetic wave called a surface plasmon polariton. The researchers used a photon scanning tunneling microscope (PSTM) to visualize the SPP propagation by scanning the tip over the metal structure. In a sense, this microscope played the role of the screen located at a fixed distance from the slits, where observers view the interference pattern. In contrast, the PSTM had the ability to image the flow of SPPs over the metal structure.When put in action, an optical evanescent wave was used to launch SPP waves along the surface of the gold. As the SPPs traveled along the waveguides, they excited specific polariton modes in the stripes, enabling these waves to propagate only along these stripes. Further along above the patterned film, an apertured cantilever probe scattered the waves toward a photodetector, which measured the local field intensity and enabled imaging of the diffraction pattern by scanning the surface.Zia and Brongersma’s results closely resembled the interference pattern of Young’s double-slit experiment. Like macroscopic light waves, the pure SPPs exhibited an interference pattern where the two diffracted beams overlap. These experimental results also closely correlated with the researchers’ simulations.The experiment may also help to settle a subject of contention among scientists, by giving support to the idea of an effective diffraction limit for the lateral confinement of SPPs on metal stripe waveguides. In other words, some SPP wave modes will be too small to exhibit interference on a metallic waveguide. The researchers explain that this limit will have important implications for how photonic systems can interface with electronic devices, which can have deeply sub-wavelength dimensions.“Nanoscale photonic systems will have to rely on more strongly confining SPP waveguides that exhibit a deep subwavelength optical mode,” Brogersma explained. “The notion of a diffraction limit for stripe waveguides is not in disagreement with the existence of such strongly guiding SPP waveguides that allow for short distance information transport with nanoscale optical modes/beam diameters. It would have been great if metal stripes on a substrate would have guided light (SPPs) below the diffraction limit, as such structures resemble metallic interconnects that currently carry electronic signals on a chip.”This ability of some metallic (plasmonic) waveguides to guide light well below the diffraction limit, however, is unique to metal structures and impossible to attain in dielectric waveguides or optical fibers. “Despite this substantial difference [between light at the nanoscale and at the macroscale], it turns out that light propagating in dielectric waveguides exhibits a lot of similarities to light (SPP) propagation along the surface of metallic structures,” Brongersma said. ”The similarities can be exploited to help the design of new plasmonic components by leveraging decades of work on dielectric structures.”Brongersma added that some of these devices may include plasmonic sources, modulators, transistors, and detectors that operate at the nanoscale.Citation: Zia, Rashid, and Brongersma, Mark L. “Surface plasmon polariton analogue to Young’s double-slit experiment.” Nature Nanotechnology, Vol. 2, July 2007, doi:10.1038/nnano.2007.185.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. Surface plasmon polaritons, or SPPs, occur on the surface of a metal film when struck by a light wave. Because SPP waves run parallel to the metal film, they can help to enhance the surface sensitivity for spectroscopic measurements that use light scattering techniques. Other potential uses of this technology—known as “plasmonics”—include the ability to confine light to very small dimensions, control the colors of materials, and transmit information on a computer chip.However, before these applications can be realized, researchers must understand the fundamentals of the interaction of light and matter on the nanoscale. To do so, Zia and Brongersma designed a version of the 19th century double-slit experiment first used by Thomas Young to detect interference patterns of light waves. (Today the experiment is most famously known in quantum mechanics, where single particles such as atoms or photons also exhibit wave-like interference.)“The experiments have shown that carefully engineered structures are needed to manipulate light at the nanoscale,” Brongersma told PhysOrg.com. “However, such structures do exist and enable new devices to be realized and interesting fundamental studies on the nature of light at the nanoscale. It is exciting to think about the possibilities. Every application where light is used can now potentially be miniaturized with plasmonics, and experiments can be performed at smaller length scales. With conventional (dielectric), lenses we were never able to explore the nanoscale with light or the nature of light at the nanoscale.”In their study, Zia and Brongersma created a slightly different version of Young’s original experiment. Two gold stripes protruding on a 48-nm-thick gold film, which served as waveguides for the SPPs, played the role of the traditional two slits. The stripes’ dimensions—each 2 micrometers thick and separated by a gap of 2 micrometers—were important because, as waveguides, they support only the lowest-order SPP mode (called a “quasi-transverse magnetic leaky mode”). center_img Before nanotechnology can reach its full potential, researchers must understand the way things work on the nanoscale—which is often very different from the macroscopic world. One of these areas is light, and how light interacts with matter on tiny scales. On-chip excitation of nanodiamonds embedded in plasmonic waveguides Citation: Understanding light at the nanoscale: a nano-sized double-slit experiment (2007, July 17) retrieved 18 August 2019 from https://phys.org/news/2007-07-nanoscale-nano-sized-double-slit.html Explore furtherlast_img read more


Axions Not Cause of Unexpected Observation

first_imgScientists from France have shown that hypothetical axion-like particles cannot explain some unexpected observations in an Italian experiment carried out last year. Ruling out axions will likely subdue some of the renewed interest in axion searches, currently underway at several major institutions. Researchers Cécile Robilliard et al., with group members from the Université Paul Sabatier Toulouse, the Centre National de la Recherche Scientifique, and École Polytechnique, have published their results in a recent issue of Physical Review Letters. The results invalidate the axion interpretation of the PVLAS optical measurements with a confidence level greater than 99.9%. “If it were detected, the axion would be the first particle beyond the standard model, which would lead to a model crisis,” Robilliard told PhysOrg.com. “Besides, depending on its parameters, the axion might contribute to dark matter, which forms 25% of our universe.”In 2006, the Italian collaboration PVLAS (Polarizzazione del Vuoto con LASer), designed to detect the optical non-linearity of quantum vacuum, made an unexpected observation. The team found that a magnetic field could generate a rotation of the polarization plane of linearly polarized light in a vacuum. The effect, called magnetic dichroism, is common but had never been observed in a vacuum and is not predicted by quantum electro-dynamics. The PVLAS researchers suggested that axion-like particles, converted from photons in a process called the Primakoff effect, might explain the observation. But later, in June 2007, the PVLAS collaboration retracted their original observations, explaining that the observations were due to instrumental errors; after they upgraded their apparatus, the light rotation was no longer observed.Nevertheless, the initial observation had already sparked new interest in the search for axion-like particles—light, neutral, spin-zero bosons that were first proposed 30 years ago to solve the strong-CP problem in particle physics, but never detected. Experiments to detect axions at DESY in Germany, CERN in Switzerland, Jefferson Laboratory in Virginia, and Fermilab in Illinois are currently under construction. For particle physicists, the CP problem is on the same order as the problem of beta decay in the 1930s, which led to the neutrino hypothesis. The neutrino wasn’t detected until two decades later, in 1956. But Robilliard and her colleagues’ result may dampen some of the excitement. They have presented a photoregeneration experiment popularly called “light shining through a wall.” In the set-up, photons are converted into axion-like particles in a magnetic field. The photon beam is aimed at a 15-mm-wide aluminum wall, which blocks the photons, but allows any axion-like particles to pass through. In a magnetic field on the other side of the wall, the axion-like particles are converted back into photons and detected. 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. Citation: Axions Not Cause of Unexpected Observation (2007, November 20) retrieved 18 August 2019 from https://phys.org/news/2007-11-axions-unexpected.html Experimental set-up of the current study. Credit: Cécile Robilliard et al.center_img Explore further Is dark matter made of axions? The main difficulty for this type of experiment lies in detection, since optical shielding needs to be perfect and detector background very low to achieve sensitive detection. The scientists overcame this challenge by using a pulsed laser and pulsed magnetic field in synchronization, enabling the single-photon detector to measure very small conversion rates. In contrast, most experiments use continuous lasers and magnetic fields, which is very demanding on the detector.With this optimal detection apparatus, as well as optimizing other variables (such as the magnetic field length), the researchers didn’t detect any regenerated photons on the far side of the wall. Based on their calculations of the limits of the axion-like particle mass and the coupling of an axion-like particle with two photons, the researchers could exclude the possibility of axion-like particles in this model at greater than a 99.9% confidence level. In the future, they plan to improve their apparatus to achieve even more stringent limits on axion-like particles.“My opinion is that, now that the PVLAS axion-like particle has been excluded by us with a confidence level better than three sigma, and the PVLAS collaboration has retracted their 2006 paper, the situation is the same as before the PVLAS 2006 results,” said Robilliard. “As far as I understand, there is no reason anymore to look for axion-like particles in the range of mass and coupling constant that have been already excluded by experiments like CAST or ADMX or by astrophysical observations.“By contrast,” she added, “detecting the axion is still a major experimental challenge in particle physics.”More information: Robilliard, C., Battesti, R., Fouché, M., Mauchain, J., Sautivet, A.-M., Amiranoff, F., and Rizzo, C. “No ‘Light Shining through a Wall’: Results from a Photoregeneration Experiment.” Physical Review Letters 99, 190403 (2007). Copyright 2007 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.last_img read more


Mouse glove is designed for new comfort zones

first_imgWhile the mouse glove is a new entrant for the Bellco product family, the mouse glove concept is hardly new. Innovative students as well as businesses have been playing with the concept for years. MIT students created interest in 2010 because they developed their version of a mouse glove inspired by a Tom Cruise movie. They were gratified to see they could construct something similar to what Cruise’s character had for less than one hundred dollars. The glove has buttons worn on the finger that allow the user to perform left and right clicks—positioned on the index finger and pressed using your thumb–, an off and on switch, and LED. The glove set includes a USB module that you plug into your computer’s USB port. The glove works with Androids, Linux, Mac and Windows systems.To scroll, the glove wearer uses wrist movements to go up and down the page. The mouse is wireless and rechargeable with the USB port; you can control your computer up to 35 feet away, which is another key selling point besides comfort, from Bellco.“No desk needed,” says the company’s ad;”sit back and relax from your big chair and control your big screen computer or Internet TV.” That “more,” as promoted by Bellco, includes wireless freedom and comfort in no longer having to hold on to a physical mouse for long periods of time and being “stuck” at a workstation. (PhysOrg.com) — Yet another alternative to the conventional computer mouse is being marketed, this time a pull-on glove that behaves as a mouse. The Ion Wireless Air Mouse Glove is from a Cocoa, Florida-based company, Bellco Ventures, which describes itself as specializing in new product development and marketing. The mouse glove can serve up functions carried out in the conventional mouse—right click, left click, scrolling, and more. New sensor glove may help stroke patients recover mobility Excessive use of hand movements while operating a computer and mouse has led some computer users to complain of sore hands and wrist problems, including carpal tunnel syndrome. In response, there have been attempts by gadgeteers as well as entrepreneurs to explore new directions in mouse design. Internet technology site reactions to Bellco’s announcement have been mixed, ranging from “odd but interesting,” to a “niche mouse” to strangest ever seen, to doubts that the glove, even though intended to relieve the discomfort of prolonged use of a conventional mouse, can be comfortable if worn for long work stretches. Packaged in blister packs, the new mouse-glove is selling for $79.99. Explore further Citation: Mouse glove is designed for new comfort zones (2012, February 28) retrieved 18 August 2019 from https://phys.org/news/2012-02-mouse-glove-comfort-zones.html Last May, an episode on Revision3 Internet Television announced “Today we are building a mouse glove,” and the announcer showed how. In 2002, a 16 year-old made news when he announced he designed a mouse glove for people suffering from repetitive stress injury. His prototype was also a mouse in a glove. At Cornell, in past years, a project called the Airmouse Initiative designed a motion-sensing glove with buttons to plug into a computer and function as a mouse. At North Carolina State University’s College of Engineering, students said they had come up with a glove where sensors were attached to the ends of each digit; touching the thumb to other digits acted as a click and activated hotkeys. In 2012, Bellco clearly sees a broadened market for its computer mouse in a glove, from those suffering from hand ailments to those ready to move on to Internet television and home entertainment media including games. The Bellco mouse glove will not only be feeding into the interests of computer users looking for a new kind of mouse but also into interests of users who are always ready to explore new concepts in remote control. © 2011 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.last_img read more


Researchers get mixed results in training dogs to sniff out lung cancer

first_img Dogs have made headlines over the past several years as some have alerted their owners to health problems that have sometimes turned out to be cancer—in some cases, actually saving their lives. Scientists believe dogs are able to smell some types of cancer by detecting chemicals expelled in the breath. In this new effort, the researchers sought to learn whether dogs might serve as a suitable tool for use in detecting lung cancer in people.The experiment consisted of training six dogs of various breeds (which had all been trained in other sniffing skills such as finding people covered by snow in an avalanche) over the course of six months to respond to chemicals in the breath of human cancer patients. The dogs were then tested on their skills by exposing them to the breath of 122 human volunteers—29 of whom were lung cancer patients at various stages of treatment.The researchers report mixed results—the dogs reported smelling cancer 78.6 percent of the time in the cancer patients, which was good, of course. But they also reported not smelling cancer in the breath of the cancer-free volunteers only 34.4 percent of the time. The study was conducted in a double-blind manner to eliminate bias, but doing so might have introduced errors by the dogs, the team reports, because it added extra stress. Dogs, they note, are also prone to distraction from a number of causes (boredom, fatigue hunger, etc.) which can also lead to errors. They believed that changing certain aspects of the testing environment might lead to a better outcome. Meanwhile, other researchers believe a better solution would be to create an artificial nose that is as sensitive as that of a dog to overcome the problem of using live animals. (Phys.org)—A team of researchers at Krems University Hospital in Vienna Austria has found mixed results while conducting studies to determine the viability of using dogs to detect lung cancer in human beings. In their paper published in the Journal of Breath Research, the team describes their study and results and suggest ways of improving the performance of dogs used for such a purpose. Journal information: Journal of Breath Research Dogs can sniff out lung cancer, pilot study shows More information: Klaus Hackner et al. Canine scent detection for the diagnosis of lung cancer in a screening-like situation, Journal of Breath Research (2016). DOI: 10.1088/1752-7155/10/4/046003AbstractThe prognosis in lung cancer depends largely on early stage detection, and thus new screening methods are attracting increasing attention. Canine scent detection has shown promising results in lung cancer detection, but there has only been one previous study that reproduces a screening-like situation. Here breath samples were collected from 122 patients at risk for lung cancer (smokers and ex-smokers); 29 of the subjects had confirmed diagnosis of lung cancer but had not yet been treated and 93 subjects had no signs or symptoms of lung cancer at the time of inclusion. The breath samples were presented to a trained sniffer dog squadron in a double-blind manner. A rigid scientific protocol was used with respect to earlier canine scent detection studies, with one difference: instead of offering one in five positive samples to the dogs, we offered a random number of positive samples (zero to five). The final positive and negative predictive values of 30.9% and 84.0%, respectively, were rather low compared to other studies. The results differed from those of previous studies, indicating that canine scent detection might not be as powerful as is looked for in real screening situations. One main reason for the rather poor performance in our setting might be the higher stress from the lack of positive responses for dogs and handlers. Explore furthercenter_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. © 2016 Phys.org Citation: Researchers get mixed results in training dogs to sniff out lung cancer in humans (2016, September 29) retrieved 18 August 2019 from https://phys.org/news/2016-09-results-dogs-lung-cancer-humans.html Credit: CC0 Public Domainlast_img read more


Camera able to capture imagery of an optical Mach cone

first_img Most everyone knows that when an object like a jet moves faster than the speed of sound, an acoustic cone is created in its wake that can be heard as a sonic boom. Scientists have theorized that the same type of phenomenon could occur with light, but until now, have not be able to prove it by capturing images of it in action. In this new effort, the researchers have done just that, and have developed an image capturing system capable of taking images of other ultrafast events, as well.To capture imagery of an optical Mach cone, the researchers approached the problem from both sides—by developing a superfast imaging system and by slowing down light.The second part was easy; all they had to do was shine a laser through a medium—in this case, a tunnel with dry ice particles that was placed between plates made of aluminum oxide powder and silicone rubber. The light from the laser subsequently traveled faster as it moved through the tunnel compared to the plates, allowing for the formation of an optical Mach cone. Journal information: Science Advances PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen © 2017 Phys.org (Phys.org)—A team of researchers at Washington University in St. Louis has built a camera apparatus capable of capturing moving imagery of an optical Mach cone. In their paper published in the journal Science Advances, the team describes their image capturing system and other possible applications of the technology. PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen More information: Jinyang Liang et al. Single-shot real-time video recording of a photonic Mach cone induced by a scattered light pulse, Science Advances (2017). DOI: 10.1126/sciadv.1601814AbstractUltrafast video recording of spatiotemporal light distribution in a scattering medium has a significant impact in biomedicine. Although many simulation tools have been implemented to model light propagation in scattering media, existing experimental instruments still lack sufficient imaging speed to record transient light-scattering events in real time. We report single-shot ultrafast video recording of a light-induced photonic Mach cone propagating in an engineered scattering plate assembly. This dynamic light-scattering event was captured in a single camera exposure by lossless-encoding compressed ultrafast photography at 100 billion frames per second. Our experimental results are in excellent agreement with theoretical predictions by time-resolved Monte Carlo simulation. This technology holds great promise for next-generation biomedical imaging instrumentation. A graphic depicting the capture of a superluminal photonic Mach cone using loss-less encoding compressed ultrafast photography. Credit: Jinyang Liang and Lihong V. Wang Play Experimentally imaged laser pulse propagation under a subluminal condition. Credit: Liang et al. Sci. Adv.2017;3:e1601814 center_img Explore further Citation: Camera able to capture imagery of an optical Mach cone (2017, January 23) retrieved 18 August 2019 from https://phys.org/news/2017-01-camera-capture-imagery-optical-mach.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. Play Narration and animation of the LLE-CUP system. Credit: Jinyang Liang and Lihong V. Wang To capture imagery of the cone, the researchers installed three CCD cameras next to the cone-generating apparatus, one of which was a streak camera (it works by converting photons to electrons and bending the path they take). The streak camera was also fitted with patterned filters that allowed for capturing still 2-D sequences of images, each of which was assigned a code—after a cone was created and imaged, a 3-D image of it was created by combining the 2-D pieces in ways reminiscent of a CT scanner. The other two cameras were used to provide more perspective and to improve resolution.The result of the effort was the first ever video of the cone-shaped wake of light known as a photonic or optical Mach cone. The researchers suggest the same technique could be used to capture imagery of other events such as individual neurons firing—they note it is capable of capturing images at speeds up to 100 billion fps. PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Play First author Jinyang Liang discussing why the loss-less encoding compressed ultrafast photography system is novel. Credit: Jinyang Liang and Lihong V. Wang Imaging at the speed of lightlast_img read more


Researchers report evidence that fruit plants evolved to offer seed dispersers an

first_img More information: Omer Nevo et al. Fruit scent as an evolved signal to primate seed dispersal, Science Advances (2018). DOI: 10.1126/sciadv.aat4871 How fruits got their eye-catching colors A red-bellied lemur (Eulemur rubriventer) feeding at dusk, Ranomafana National Park, Madagascar. Credit: N. Rowe & Centre ValBio Citation: Researchers report evidence that fruit plants evolved to offer seed dispersers an attractive scent (2018, October 4) retrieved 18 August 2019 from https://phys.org/news/2018-10-evidence-fruit-evolved-seed-dispersers.html Explore further © 2018 Phys.org Many plants that bear fruit rely on animals to disperse their seeds—the animals eat the fruit and then deposit the seeds on the ground when they defecate. Many animals are considered dispersers for many types of fruit plants, but for the relationship to work, the animal must eat the fruit at the right time—when it becomes ripe. Eating before that time would be useless, because the seeds have not matured, and after that time, they may have begun to degrade. Thus, to ensure that the seeds are eaten at the right time, the fruit has to offer a means for signaling the dispersers. Prior research has suggested that color changes offer a strong signal to sharp-eyed dispersers such as birds. But what about animals with poor vision? Some in the field have suggested such animals use scent—but to date, no one has been able to prove it. In this new effort, the researchers have gone a long way toward doing just that.To find out if plants have actually evolved to use scent as a signal to dispersers, the researchers collected 434 unripe fruit specimens and 428 ripe ones in the wilds of Madagascar. Their aim was to find out if some of the plants had evolved to entice lemurs at just the right time. Lemurs have poor eyesight and are color blind; thus, it is doubtful that they use vision as a means of choosing which fruit to eat. But they have a very good sense of smell. Some of the ripe fruit the group collected was colorful, and some was not. Fruit that changes color with ripeness were found to be eaten mostly by birds. Lemurs, on the other hand, mostly ate fruit that did not change color. The researchers tested the fruit the lemurs preferred and found it to be twice as aromatic as other fruit, but only when ripe. And the fruit eaten by birds did not change much in smell at all. The researchers also noted that the lemurs always sniffed fruit before eating or discarding, and generally chose only fruit that was ripe.center_img The researchers claim their study strongly suggests that some trees in Madagascar have evolved in a way to use scent as a means of disperser enticement. Journal information: Science Advances A team of researchers from Germany, Madagascar and the U.S. has found evidence that suggests fruit-bearing plants have evolved to produce fruit that communicates ripeness with a particular smell that attracts the animals that will disperse its seeds. In their paper published in the journal Science Advances, the group describes their study of fruit eaten by lemurs in Madagascar. Red-bellied lemurs (Eulemur rubriventer) in Ranomafana National Park, Madagascar. Credit: N. Rowe & Centre ValBio 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


Repurposing dimethyloxalylglycine to inhibit glutamine metabolism

first_img Citation: Repurposing dimethyloxalylglycine to inhibit glutamine metabolism (2018, October 9) retrieved 18 August 2019 from https://phys.org/news/2018-10-repurposing-dimethyloxalylglycine-inhibit-glutamine-metabolism.html Credit: CC0 Public Domain Journal information: Nature Chemical Biology A team of researchers from the U.K. and the U.S. has found that a drug used to study hypoxia can also be used to inhibit glutamine metabolism—a possible means for targeting cancer cells by cutting off their supply line. In their paper published in the journal Nature Chemical Biology, the group explains their study of the drug and its new possible use in targeting tumors. Barbara Nelson, Daniel Kremer and Costas Lyssiotis with the University of Michigan have written a News and Views piece on the work done by the team in the same journal issue. Scientists show that drugs targeting tumor metabolism will not stop natural killer cells More information: Louise Fets et al. MCT2 mediates concentration-dependent inhibition of glutamine metabolism by MOG, Nature Chemical Biology (2018). DOI: 10.1038/s41589-018-0136-ycenter_img The researchers began their study by noting that a lot of tumors require glutamine to survive—they utilize it in a process called glutaminolysis. Prior research had revealed that glutamine can be involved directly in biosynthetic processes or it can be converted to glutamate. In the latter case, it becomes de-animated to α -Ketoglutarate (αKG)—the de-animation process is sometimes catalyzed by glutamate dehydrogenase (GDH), where KG and ammonia are produced, and at other times by transaminases. Also, noting that αKG is a key feature in relevant metabolic pathways, suggested that its analog, a drug called dimethyloxalylglycine (DMOG) might be useful in inhibiting glutamine used by cancer cells. To find out if this might be the case, the researchers hydrolyzed DMOG, producing methyloxalylglycine (MOG), which incited cytotoxicity when transported by monocarboxylate transporter 2 (MCT2). They report that the end result was a decrease in tricarboxylic acid, which is derived from glutamine. They also found a reduction in mitochondrial respiration and a decrease in ATP production. A closer look showed that the use of MCT2 allowed MOG to gain entry to cells with high enough concentrations to slow the production of enzymes involved in glutamine metabolism. Thus, they report, MCT2 dictates how well NOG can perform in inhibiting glutamine metabolism.The result of the work is the establishment of a new means of causing cytotoxicity, effectively reducing the utilization of glutamine by cells. The next step will be to find out if the inhibition of GDH and isocitrate dehydrogenases by NOG are alone responsible for the cytotoxicity observed or if there are other unknown elements at play. 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. © 2018 Phys.orglast_img read more


Go for the killer ambience

There are places where you go for the food. Where the ambience doesn’t matter. Even if it’s a roadside shack, you would keep going there just because your stomach growls when your mind visualises your favourite dishes from there. And then there are places where you would want to go for the ambience. And not want to budge an inch even though it might be late and they would want to shut shop for the day. The food? That is an added attraction. FIO is one of these places — where you would want to keep sitting, sipping your drink and munching on something. The ambience is just excellent. That the food is worth munching on is just the icing on the cake. Also Read – ‘Playing Jojo was emotionally exhausting’I went to FIO one fine night, when the air was balmy and the stars were shining bright. The restaurant is bang in the middle of the Garden of Five Senses and has an outdoor sitting area too. And there I sat, to the sound of crickets, greenery all around me. At nearly 10 pm, the place was choc a bloc. On top of that, there was a birthday party going on at the far end. But even that could not take away from the serenity of the place. It is one where you can lose yourself in the quiet beauty. Also Read – Leslie doing new comedy special with NetflixYou get back to modern world when the waiter presents the menu card. It is a tablet which has the menu stored. Click on a dish, see its ingredients and what it looks like and only then place your order. For those unsure of Continental and Mediterranean, here’s the perfect foil. Now no more throwing darts (read ordering) in the dark. I ordered some Bruschette di Pomodoro (see recipe) for antipasti and it was quite good and went perfectly with the strong Long Island Iced Tea that I ordered. Main course consisted some finely made wood-fired pizza. Choices are plenty, also for vegetarians. Ditto for the liquor menu. Next time you want to throw a party or spend a quiet dinner with the man, this is where you should head.DETAILAt: FIO, Gate No. 1, Garden of Five Senses, Saidulajab Timings: Noon to 1 am Phone: 9971004531Meal for two: Rs 3,500 + taxes read more


Morning ragas that awaken the senses

first_imgAs the weather of the Capital warms up the soulful musical and melodies of the Morning Raga came to an end at India Habitat Centre. Pandit Ajoy Chakrabarty concluded the season with his melodious renditions. The last concert of the morning Ragas was in collaboration with ITC Sangeet Research Academy.The show opened with an original composition of Raag Bharavi by Pt. Ajoy Chakrabarty. Starting a concert with raag Bharavi is quite unusual but, marking the end of Morning Raga series,the performance and the rendition left its audience mesmerised and wanting for more. Also Read – ‘Playing Jojo was emotionally exhausting’As the performance progressed Pt Ajoy Chakrabarty  presented one of his self composed Vilambit Khayal followed by Madhyalay composition and three traditional rut compositions of Agra Gharana and Patiala Gharana. He further enthralled the audience with another rarely heard raga Lalit Pancham in which he presented two compositions of Pt. Gyan Prakash Ghosh in Vilambit and Dhrut.As the spirits of the music enthusiasts soared with back to back soulful musical performances he next chose Raag Kalingada in which he presented a Thumri. The concert finally had to come to a conclusion with Shayama Sangeet in Raag Shudh Kalyan and chanting in Sanskrit.  The next season of Morning ragas with new artistes and various classical performances will be back again in the month of October.Earlier maestros featured in Morning Ragas include names like Ustad Amjad Ali Khan, Vidhushi Girija Devi, Subha Mudgal, Ustad Wassifuddin Dagar to name a few. These maestros have mesmerised the audience with their music and attracted a crowd of over 300 keen music aficionados per show.last_img read more


Raids on in WB Jkhand following key JMB mans arrest

first_imgNIA and other security agencies are carrying out raids in various parts of West Bengal and Jharkhand based on inputs provided by Tarikul Islam alias Sadiq, a chargesheeted accused in Burdhwan blast case, who was arrested last night.Islam, who is alleged to be an active member of banned Jamaat-ul Mujahideen Bangladesh (JMB) terror group, is believed to have given leads to NIA prompting the probe agency to carry out raids at various places in the two states, official sources said on Wednesday. Also Read – Rain batters Kolkata, cripples normal lifeSo far, some cards used in mobile phones and laptops to store data have been recovered at the instance of Islam who has since been taken on a transit remand to Kolkata where he will be produced before the designated NIA court on Thursday, the sources said.Islam, who was arrested from Ramgarh district of Jharkhand by a team of NIA and Anti-Terror Squad of Jharkhand police, carried a cash reward of Rs five lakh as he is alleged to be an important member of ‘Shoora’, the decision-making body of JMB. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedNIA has already chargesheeted him for his alleged role in the Burdwan blast which occurred in a house on October 2 last year, leaving two persons dead.During investigation of the case, NIA claimed that Islam was a part of larger conspiracy of JMB to organise terror attacks in Bangladesh and in India and had been frequently entering India illegally, at different times since the year 2008-2009. He is also alleged to have obtained false identity documents on assumed Indian identities, by submitting forged documents, after which he married an Indian girl from Sahebganj, Jharkhand. The marriage was solemnised at Simulia madrasa in Burdwan, West Bengal where the terrorist training camps were organised by JMB.He had been quietly residing at Village Islampur of Sahebganj district under an assumed identity of Raihan Shaikh.Earlier he had also resided at a hideout in Village Namo Chachanda of West Bengal.NIA also alleged that the probe showed that Islam, along with other accused, was an active member of JMB who attended terrorist training camp organised by senior members of the terror group.NIA took over the case from West Bengal police a few days after the explosion when international links started emerging. Investigators have found that improvised explosive devices (IEDs) were being fabricated in the house where the explosion took place and later smuggled to Bangladesh.NIA has so far found that members of JMB has established a network in different places like Murshidabad, Nadia, Malda, Birbhum, Burdwan in West Bengal and Barpetta in Assam, Sahibganj and Pakur in Jharkhand.last_img read more


Rs suffering from low fever diesel prices highest ever CM

first_imgKolkata: Chief Minister Mamata Banerjee attacked the Centre for its set of “anti-people” steps that have led to the rupee crash to its lowest level with a steep hike in petrol and diesel prices.At the same time, she once again pointed out that how badly the country’s economy was hit due to the hasty implementation of the Goods and Services Tax (GST). In a tweet on Friday, the Chief Minister has stated: “Rupee suffering from low fever. Petrol and Diesel prices highest ever.” Also Read – Rain batters Kolkata, cripples normal lifeIt may be mentioned that with the increase in the crude prices, the rupee slumped at 71 against the US currency. At the same time, the petrol and diesel prices in Kolkata are Rs 81.44 and Rs 73.06 respectively on Friday. She further stated in her tweet that “Foreign Exchange Reserves have fallen by $21.84 billion between March end and August 3. Current Account Deficit is moving up towards 2.8 per cent of GDP.” Taking a dig at the Centre for its hasty decision to step into the GST regime, Banerjee further tweeted: “The unprepared bravado of launching GST has resulted in a massive loss to State revenues to the tune of Rs 48,178 crore during July 2017 – March 2018.” Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedStating the adverse effect of the hasty implementation of the GST, the Chief Minister further mentioned: “There are now charges of racketeering, black marketing and hawala, due to the makeshift filing of GST, without supporting invoices.” Raising concern over the present situation, she has stated in the tweet: “Very dangerous situation for the common people of India! Where are we heading to?????” It may be recalled that the Chief Minister had earlier tweeted raising concern about the rupee hitting a new low, stating that “small business will be further killed” after the demonetisation disaster. This comes at the time when the Mamata Banerjee government has taken several steps for the benefit of the people and around 8.59 crore are getting the benefits of the Khadya Sathi scheme under which rice is distributed at Rs 2 per kg. On Friday, the Chief Minister has also tweeted remembering the martyrs of 1959 Khadya Andolan. In the same tweet she has stated: “In Bangla, we provide food security to 90% (8.59 crore) of the state’s people through the Khadya Sathi scheme.” Floral tributes were paid to the martyrs of Khadya Andolan at Nabanna on Friday.last_img read more


Online bullying ups aggression in kids

first_imgHave you ever been bullied in school, college or social media? A new study shows that the combined effect of both face-to-face and cyber-bullying may increase the risk of aggressive behaviour in teenagers.These bullied teenagers were twice as likely to show aggressive behaviours themselves like verbal hostility, physical fighting and damaging property.Teenagers who were victims of both face-to-face and cyber-bullying, representing three percent of the youth, were more than twice as likely as those experiencing just one form of bullying to engage in aggressive behaviours.“Victims who had been subjected to multiple forms of peer aggression were at increasingly greater risk of showing aggressive behaviours themselves,” said senior author Andrew Adesman from Cohen Children’s Medical Center of New York.“These behaviours may involve retaliatory measures against their aggressors, acting aggressive in order to fend off future bullying attempts, or worse, learning by example and engaging in bullying of previously uninvolved peers,” Adesman added. The team analysed adolescents between ages 10 and 17, on how they behaved after experiencing face-to-face bullying, cyber-bullying and both.The results revealed that overall, 43 percent of the teens in the study reported having been the victim of face-to-face bullying, while seven percent reported that they experienced some form of cyber-bullying.Out of the teenagers who experienced both forms of victimisation, 38 per cent showed aggressive behaviour, compared with 15 per cent of those who were cyber-bullied and 4 percent of those were victims of face-to-face bullying.“This phenomenon may lead to a vicious cycle whereby bullies create bullies out of those they victimise.”The study was scheduled to be presented at the ongoing Pediatric Academic Societies 2016 Meeting in Baltimore in the US.last_img read more


Elaborate security arrangements in place

first_imgKolkata: Kolkata Police has almost turned the Red Road and its surrounding areas into a fortress as the city is all set to witness the grand Durga Puja Carnival 2018 on Tuesday. As several VVIPs will be present along with Chief Minister Mamata Banerjee, the security arrangement has been made in different tiers.According to police sources, 3,000 police personnel will be deployed on Tuesday for Puja Carnival security. Vehicular movement on Red Road will be restricted from early Tuesday morning. Though police personnel will be deployed from Monday night on Red Road, the whole area will scrutinised thoroughly after imposing vehicular movement restriction. Sniffer dogs will be used as well. The bomb squad of Kolkata Police will also be engaged. Also Read – Rain batters Kolkata, cripples normal lifeApart from the pre-event security arrangement, several measures have been taken to ensure foolproof security of all guests till the end of the carnival. There will be several teams of police comprising Special Action Force (SAF), Rapid Action Force (RAF) and Quick Reaction Team (QRT) deployed at Red Road and its surrounding areas. These units will check for any unauthorised and suspicious movement in the area. Apart from the specialised forces, police personnel from the Special Branch will also be deployed. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedPolice personnel in plain clothes will also be there among the spectators. Special security arrangements have been made for the foreign diplomats and delegates who will be present at the event. Six watchtowers have also been erected to keep a hawk’s eye on the area. Adequate number of CCTV cameras have been installed as well for proper surveillance. Sources have informed that drones will also be used during the programme to avoid any untoward incident. Vehicular movement on Red Road will be restricted from the morning on Tuesday, whereas Hospital Road, Casuarina Avenue and Mayo Road might be partially closed for traffic movement. Normal vehicular movement will be allowed through Jawaharlal Nehru Road. Vehicular movement on Kidderpore Road from Hastings Crossing to Lovers Lane will be closed from 2 pm till the end of the carnival on Tuesday.last_img read more


Commerce stream students most likely to bunk classes feel teachers

first_imgKolkata: Teachers from different institutions in the city have shared contrasting opinion on the agitation of students from different colleges over their demand to appear for examinations even with low attendance. Interestingly, majority of students who agitated belong to theCommerce stream. According to experts, students affinity towards private tuition and pursuing other professional courses have resulted in class bunking. Eminent educationist and professor of Jadavpur University Kanak Sarkar said: “Skipping classes in commerce stream is nothing unusual. They have the opinion that there is no use in attending classes for the sake of a career. They are often found to go for other professional courses.” Also Read – Rain batters Kolkata, cripples normal lifeA section of teachers opine that these students believe classroom teaching will not help them in getting employed. They believe in employment through competitive examinations and professional courses. They also pursue studies related to Chartered Accountancy besides their study in BCom or MCom. Head of Commerce in Calcutta University Jadab Krishna Das said: “The students of BCom depend on private tuitions and bunk classes at will. But under the current system of Calcutta University students need to have 60 percent attendance and there is 10 marks allotted for attendance. So, they cannot stay away Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedfrom classes.” Under the current system, attendance is uploaded on the website from time to time so teachers cannot tamper with attendance. Teachers also maintained that with the current trend of movement among students, colleges should organise workshops or similar programmes and make students aware about the rules regarding attendance. The Calcutta University’s syndicate meeting is scheduled to be held on Monday where the issue of attendance will come up for a discussion.last_img read more


2 injured in gas cylinder explosion in Howrah

first_imgKolkata: Two youths were injured when a gas cylinder exploded at Bagnan in Howrah on Wednesday night.The injured victims were immediately rushed to RG Kar Medical College and Hospital. According to police, a gas balloon seller and a Class IX student from the locality were injured in the incident. On the occasion of Netaji’s 122nd birth anniversary, a cultural programme was going on in the area. The gas cylinder suddenly burst leaving the two seriously injured. Locals heard a loud thud and found the two youths wreathing in pain. They initially took the injured victims to Uluberia Sub-Divisional Hospital and later shifted them to RG Kar Medical College and Hospital as their condition deteriorated. The health condition of both the victims is stated to be serious. After being informed police reached the spot and cordoned off the area. They also collected samples from the place of the incident for the sake of investigation. Cops are investigating if there were faults on the part of the balloon seller. A detailed probe has been initiated.last_img read more


Bihar Utsav 2018 begins at INA

first_imgBihar Foundation Day is celebrated every year on March 22 since the year 2010. To mark the occasion, Department of Industry, Govt. of Bihar is organizing 15-days long “Bihar Utsav 2018 and Handloom and Handicrafts exhibition-cum-sale” at INA, Dilli Haat in the Capital from March 16 to 31. Bihar Utsav 2018 is organized in Delhi by the Bihar Government Department of Industries and BIADA (Bihar Industrial Area Development Authority). The exhibition is decorated by the Axis communication as per the theme of tourism, tradition, art and culture and ambience of Bihar. The exhibition -cum-sale of handicraft and handloom products of Bihar made by artisans of Bihar, showcase art, culture, heritage, tourism, tradition, and the ambience of Bihar. Apart from this, food stall featuring a menu of mouthwatering Bihar cuisine by Bihar tourism at INA Dilli Haat will be also an attraction for this year’s Bihar Utsav in Delhi. Also Read – Add new books to your shelfTo attract the visitors, there will be a 3D replica of historical monuments, tradition art and culture at the entrance gate of Dilli Haat and around 118 stalls of Handloom, Handicrafts. Bhagalpuri silk, Mithila paintings, Siki products, Jute products like Jute jewellery, Tikuli Art, Nepura silk of Nalanda and famous handloom bed sheets of Biharsharif will be some of the great attractions at this festival. On the occasion of Bihar Utsav cultural programmes and musical evenings will be organized between March 22 and 24 at INA Dilli Haat.last_img read more


Trinamool Congress member shot dead in West Bengal

first_imgKolkata: A Trinamool Congress member succumbed to gunshot injuries in West Bengal’s Murshidabad district, police said on Tuesday. “Jahangir Sheikh, 40, a panchayat samiti member of the Trinamool Congress, was shot at by some miscreants on Monday. He died at a nearby hospital,” said an officer of Kandi police station. The officer said that they had not received any written complaint of the killing. Whether the incident was a political clash or the result of any personal enmity will be investigated, he added.last_img


A Huge Fleet of Ghost Ships in American Waters is Creeping Towards

first_imgMallows Bay is a fairly unassuming shelter on the Maryland side the Potomac River, where the current twists and curves east. Stand on the bank and study the shallow water closely and your eye will drift over the partially-submerged hulls of ships, the eerie rotting wood and steel cadavers of the largest fleet of shipwrecks in the Western hemisphere. Some 230 vessels have been intentionally sunk in this drab spot only 30 miles down the river for Washington, D.C. They were hastily constructed steamships commissioned by the Emergency Fleet Corporation (later renamed the United States Shipping Board Merchant Fleet Corporation) to meet the demand of keeping supply lines open between the U.S. and Europe during the First World War.Mallows Bay. Photo by Amazur CC BY-SA 3.0On its formation in 1917 with the U.S. entry into the conflict, the Emergency Fleet Corporation seized control of existing ships. But there still weren’t enough for the incredible strain being put on the wartime supply lines, as more ships were being sunk by marauding U-boats than could be launched.In the first two weeks of America’s involvement, 122 ships were sunk by German submarines. The EFC was tasked with the impossible: building 1,000 steamships over 300-feet long in 18 months.The EFC was forced to requisition all merchant vessels over a certain tonnage currently under construction in the nation’s shipyards and rush them to completion as timber-only ships in an era of steel plate hulls.Aerial photograph, 1936. Mallows Bay on Potomac River below Quantico and between Sandy Point and Liverpool Point.In total half a million workers and 40 shipyards were pressed into service for the war effort, much to the irritation of the companies that owned them and the clients they were building them for — including Great Britain which had its own pressing need for more merchant vessels. Captured enemy ships were also put to use to keep the Doughboys fed and fueled for the fight against Imperial Germany.They didn’t launch 1,000 ships in the end, only 264 by 1919 and of these just 76 had been put to use before the hostilities ended in November 1918.Almost submerged shipwrecks, February 2017. Photo by F Delventhal from Outside Washington, D.C., US CC BY 2.0In 1925 the fleet was deemed surplus to requirements. Steamships had become obsolete with the move towards diesel engines, and many of the rush jobs were of such poor construction that they couldn’t be used.Left with so many ships and so little use, the corporation had them burned and scuttled — meaning deliberately sunk — in James River, and then towed to Mallows Bay for salvage.In total 106 of the existing wrecks are First World War era merchantmen and if you zoom in on Google Earth you can see the skeletal outlines of vessels beneath the green rippled surface of the water.Mallows Bay. Photo by F Delventhal from Outside Washington, D.C., US CC BY 2.0Among the ships in the bay is the SS Aberdeen which was built in an amazing 17 days for the First World War, and the car ferry SS Accomac which only left service in 1964, but older vessels were dumped there too — including a Revolutionary War longboat and schooners from the 18th century.The shallow water proved an asset, first during the Great Depression when locals made a living plundering the wrecks for scrap metal, then World War II when the steel needed to be salvaged for the war effort, and then in peace when the partially submerged wrecks were transformed into a habitat for fish and birds, including bald eagles.Mallows Bay Park. Photo by F Delventhal from Outside Washington, D.C., US CC BY 2.0Plants grow in sheltered nooks and crannies, and beavers undertake salvage of their own by gnawing at the rotting decks for wood. Now on the National Register of Historic Places, Mallows Bay is undertaking the process to be recognized as a National Marine Sanctuary.Read another story from us: Lost Final Resting Place of Celebrated Explorer Finally Found Beneath London StationAccording to LiveScience though, this ghost fleet is on the move. Findings presented to the American Geophysical Union in December 2018 by a group of fifth-grade students from JC Parks Elementary School in Maryland revealed how many of the ships have changed location, by comparing their charted positions over time.Most of the ships, it turns out, have been moving eastward downriver — some by as many as 20 miles — creepily slowly and surely towards the ocean and an even deeper watery grave.last_img read more


VIDEO Kirk Cousins puts Giants rookie QB Kyle Lauletta on the whiteboard

first_imgNo position has a bigger leap from college to the pros than quarterback. Not only are the defenses faster, smarter and quicker, but learning the NFL language can present challenges for QB’s coming from spread, no huddle college offenses.Now Giants rookie quarterback Kyle Lauletta flew in to meet with newly signed Vikings signal caller Kirk Cousins for a pre-draft tutoring session on playing the position at the NFL level. Cousins put Lauletta on the whiteboard and explained how the same play Lauletta drew up is a staple in NFL offenses, and how different teams describe it in their playbook.Cousins also pointed out that the same concepts that work within the play in college can be disrupted by faster, smarter NFL defenses. If you’re a football nerd that love x’s and o’s and quarterback play, this clip has your name written all over it.last_img read more


Pop and Belichicks rigid dynasties are eroding

first_imgGuests:Ving Rhames – Actor is in-studio to discuss Mission: Impossible – Fallout; his take on the LeBron Lakers; and how he’s still getting paid from Pulp Fiction.Nick Wright – Host of First Thing’s First joins the show to grade Colin’s attempt to design a Kawhi Leonard shoe.Caron Butler – 14-year NBA Veteran is in-studio on Carmelo Anthony’s future; why he like the Lakers Bad News Bears team full of 1-year deals.David Spade – Actor/Comedian is in-studio talking previewing his new movie Father of the Year and why he still holds a special place for Tommy Boy. Also:– Colin’s NFL Dumpster-firearchy– Russell Wilson is a tier 1 QB– Colin introduces the Kawhi Leonard ‘Stealth’ shoe Pop and Belichick’s rigid dynasties are eroding Just like the Patriots in the NFL, the Spurs have been the gold standard for NBA organizations for the better part of the last 20 years, but like Bill Belichick, Gregg Popovich’s rigid dynasty is eroding and mired in drama that would have been unthinkable at its peak.Colin thinks the success of these rigid dynasties is predicated on the superstars buying in and selling the message to the locker room. Without superstars like Brady and Duncan to sell the message, Belichick and Pop’s dominance is approaching the end.last_img read more