(PhysOrg.com) — In the early 1800s, during the peak of the Industrial Revolution, modern science revolved around steam engines and other coal-powered applications. So it may seem a bit out of place that, in 1833, an Italian physicist named G. D. Botto was performing experiments on a technique for generating hydrogen. “Hydrogen is the most common element on Earth, the lightest and the simplest in its structure,” Roberto De Luca of the University of Salerno in Italy told PhysOrg.com. “Hydrogen gas was already known to [French chemist Antoine-Laurent] Lavoisier at the end of the eighteenth century. However, the production of hydrogen, at the time Botto performed his experiment, can only be viewed as a sub-product of electrolysis. Botto’s main objective was to show to the scientific community that electricity could be obtained by a source of heat through his ingenious device.”De Luca is part of an Italian team of scientists who have revisited Botto’s experiments to investigate whether the technique could have applications for today’s energy problems. The Italian group was inspired by the convenience of Botto’s device, which can be easily fabricated and is composed of widely available materials. The researchers calculated that, although a modified version of Botto’s device has a very low power conversion efficiency, it can still produce enough electromotive force to generate hydrogen. “We learned about Botto’s idea through the invaluable work of Professor [Salvatore] Ganci [also a co-author of this study], who is an expert in the history of physics,” De Luca said. “He is now writing a book on scientific instruments constructed by physicists from the province of Genoa in the early 19th century. Among his studies, there is the device used by Botto, by which it was possible to prove that electricity could be generated by heating an array of thermocouples. Without the invaluable contribution of Professor Ganci, this work would have not been possible.” Botto’s original 19th-century device is quite simple. It consists of a chain of iron and platinum wires alternately connected as thermocouples, which are used to convert a temperature difference into an electric voltage. Botto then wrapped the chain around a wooden stick so that the iron-platinum junctions were evenly positioned on opposite sides of the stick. By heating the contraption with a flame of burning alcohol, Botto could generate an electromotive force. Further, by passing the generated electric current through water, he demonstrated how the method could be used to produce hydrogen through electrolysis. Citation: Scientists revisit 1833 hydrogen production experiment (2008, November 7) retrieved 18 August 2019 from https://phys.org/news/2008-11-scientists-revisit-hydrogen-production.html The Italian team studied Botto’s device, but made some significant adjustments. They first considered substituting copper for platinum in the thermocouples. They also proposed completely replacing Botto’s thermocouples with thermoelectric semiconductors for greater efficiency. Also, rather than use a flame of burning alcohol as the heat source, the Italian team considered using solar power to heat the thermocouples/semiconductors and create a temperature difference. They suggested that two parabolic mirrors could be arranged to concentrate solar radiation on the thermocouples and heat one side. To cool the other side (in order to create a temperature difference), the wooden stick might be replaced with a hollow electrically insulating material through which water could run to cool the desired junctions. The researchers then estimated the temperature difference, which could be used to estimate the voltage difference, which was only about 1 mV. They also estimated a small power output of about 20 mW. Despite the low power conversion efficiency, the Italians’ proposed solar-powered device could generate enough current to produce hydrogen gas through electrolysis. “We think that this idea can be used in the production of hydrogen gas directly from solar energy, through electrolysis,” De Luca said. “However, nowadays, one would not use thermocouples, as in Botto’s experiment, but could, more efficiently, use thermoelectric semiconductors to obtain a much higher power output. The important point in this work is also that, while there has always been solid scientific ground for these ideas, there has also been a lot of resilience in their applications.” As for why the researchers suggested using solar radiation to heat the device rather than a flame, De Luca emphasized the economic benefits. He and others have investigated unique, simple methods for capturing sunlight in other studies, and explained the advantages of solar energy.“It makes a great difference, in hydrogen production, to use free energy from a nuclear power plant which starts working early in the morning and stops early at night,” he said, referring to our Sun. “This energy will be free for the next five billion years, approximately. Hydrogen can thus be freely produced (unless we consider the cost of water) as long as this wonderful, perfectly clean power plant will be shining upon us. Hydrogen can then be used to run our cars and to make our houses bright at night in the future, despite the fact that Earth might sooner or later run out of oil.” More information: De Luca, R.; Ganci, S.; and Zozzaro, P. “Revisiting an idea of G D Botto: a solar thermoelectric generator.” Eur. J. Phys. 29 (2008) 1295-1300.Copyright 2008 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (Left) Botto’s iron-platinum thermocouple (a chain wrapped around a wooden stick) could generate a current when heat from a flame was applied. The heat created a temperature difference, and the thermocouples converted the temperature difference into an electric voltage. (Right) The modern proposal uses solar radiation as the heat source, with a parabolic trough solar collector, and water traveling through a hollow core as the cooling system. Image credit: Roberto De Luca, et al.
Well, sci-fi style, nightmare scenarios about the end of the world aside, the Predator system is quite real, but instead of being the ultimate killing machine, it is a visually based tracking system that might help the disabled to use computers more effectively. The developer of the Predator system is a student at the University of Surrey Zdenek Kalal, who studies at the university’s Centre for Vision, Speech and Signal Processing. He was given an award, the Technology Everywhere award, for developing the Predator system. The event was hosted by the UK’s Engineering and Physical Sciences Research Council. (PhysOrg.com) — If I told you about something called the Predator system, what would come to mind? The first thing that comes to this reporter’s mind is The Predator that was made famous in the film of the same name. So, you can how distress is a natural reaction when you hear that someone is developing one right here on earth. To trust or not to trust your friends Explore further Citation: The Predator system helps the disabled to use computers (w/ video) (2011, April 1) retrieved 18 August 2019 from https://phys.org/news/2011-04-predator-disabled-video.html © 2010 PhysOrg.com The Predator system is designed for enhanced tracking and could potentially allow a paralyzed person to use an item, such as a pen placed in a mouth, in order to operate the mouse on a computer. This technique would provide a method of communicating with the world for a traditionally isolated group.What makes this system unique is the fact that this system has the capability to learn over time, and track a user more effectively. Once and item is designated, and multiple items can be designated, one at a time, the system is able to track the item as it moves about, and even if it leaves the screen and returns.In addition to helping the disabled the system has the potential to be used in a range of biometric security options. Zdenek Kalal This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Explore further Crows are capable of distinguishing symbols, study finds More information: You sound familiar: carrion crows can differentiate between the calls of known and unknown heterospecifics, Animal Cognition, 2012, DOI: 10.1007/s10071-012-0508-8AbstractIn group-living animals, it is adaptive to recognize conspecifics on the basis of familiarity or group membership as it allows association with preferred social partners and avoidance of competitors. However, animals do not only associate with conspecifics but also with heterospecifics, for example in mixed-species flocks. Consequently, between-species recognition, based either on familiarity or even individual recognition, is likely to be beneficial. The extent to which animals can distinguish between familiar and unfamiliar heterospecifics is currently unclear. In the present study, we investigated the ability of eight carrion crows to differentiate between the voices and calls of familiar and unfamiliar humans and jackdaws. The crows responded significantly more often to unfamiliar than familiar human playbacks and, conversely, responded more to familiar than unfamiliar jackdaw calls. Our results provide the first evidence that birds can discriminate between familiar and unfamiliar heterospecific individuals using auditory stimuli. © 2012 Phys.Org (Phys.org) — Researchers at the University of Vienna have discovered that carrion crows are able to distinguish between familiar and unknown human voices. They also found, as they write in their paper published in the journal Animal Cognition, that the birds are able to do the same with other birds outside of their species, though they react in different ways. Suspecting that crows, which are among the smartest of all birds, are able to tell the difference between people they know and those they don’t based on voice alone, the team set up an experiment to find out. They recorded the voices of five people who care for a group of carrion crows living in the university’s aviary, speaking the word “hey.” They then recorded the voices of five other people who the birds had never heard, speaking the same word. Later, when the recordings were played back for the birds, the researchers noted that the crows responded much more clearly to the unfamiliar voices, turning to look right away, investigating its source. The team suggests this is because crows see humans as a potential threat and thus any voice they hear that they can’t identify needs to be paid special attention.Wondering if the birds displayed similar tendencies when interacting with other animals besides humans, the team repeated the experiment using bird calls instead of human voices. Because carrion crows tend to live and interact with other birds in the crow family, the team recorded calls from jackdaws and magpies, both of which are also considered highly intelligent. This time, when they played back the recordings for the carrion crows, they got the opposite reaction. The birds responded more clearly to the calls of other birds that they’d heard many times as opposed to calls from birds they’d never heard before. In this instance, the researchers suggest that the carrion crows on occasion team up with other such birds in cooperative efforts to find food or sound the alarm when threats are identified. This confirms prior work by other groups that had found that corvids (birds in the crow family) tend to work purposely with some birds when foraging, while ignoring others.The team suggests that the behaviors exhibited by the carrion crows in the experiments likely help crows survive in both their natural environment and in those they share with human beings. Citation: Crows found able to distinguish between human voices (2012, May 16) retrieved 18 August 2019 from https://phys.org/news/2012-05-crows-distinguish-human-voices.html Corvus brachyrhynchos or Corvus caurinus. Image: Wikipedia. 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.
Photograph of a printed WORM memory bank with 26 bits, with an optical microscope image of the bit layout at right. The bit size is approximately 200 x 300 micrometers. Image credit: Leppäniemi, et al. ©2012 IOP Publishing Ltd Copyright 2012 Phys.org 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. (a) A questionnaire card with a printed 12-bit WORM memory bank, flexible battery, and LED. (b) Roll-to-roll printing of the WORM memory banks for the card with VTT’s “ROKO” printing line. (c) WORM memory bank pre-sintering and the readout device. Image credit: Leppäniemi, et al. ©2012 IOP Publishing Ltd In terms of stability, the researchers observed the onset of a slow decline in the resistance after being stored for four months in the dark with a desiccant at ambient conditions. The decline resulted from the less-stable ‘0’ state due to self-sintering, which decreased its resistance. However, even after the 19 months of monitoring time, the researchers described the bits as maintaining a good ‘0’ state stability. In contrast, when exposed to a high temperature of 85 °C (185 °F) and a high relative humidity of 85%, the resistance underwent a rapid drop in less than three hours.To demonstrate a simple application of the WORM memory, the researchers, together with Stora Enso Oyj, manufactured 1,000 electrical questionnaire cards for the Printed Electronics Europe 2011 conference that attendees used to vote for the best booth at the conference. A flexible printed battery supplied the small write voltage (less than 10 volts), and an LED inside the card indicated the successful push of a button. The questionnaire cards represent just one possible use of the WORM memory, which the researchers hope to further improve in the future.“The goal is to provide printed memory addressing logic and reach higher bit amounts,” Leppäniemi said. “Also, improving the long-term stability via proper encapsulation requires further attention.” In this way, the technique allows for selectively and irreversibly modifying the resistance of the bits, enabling a WORM memory function. As the scientists explained, such a memory has important advantages for real-world use.“The advantage of the memory lies in the processability,” Leppäniemi told Phys.org. “The memories can be printed with high-throughput methods and the bit properties can be tailored by changing the composition of the bit ink. Also, the resistive memory provides simple, non-destructive readout when compared, for example, to printable ferroelectric random access memories.” 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: Nanotechnology The researchers, Jaakko Leppäniemi, Tomi Mattila, Terho Kololuoma, Mika Suhonen, and Ari Alastalo at the VTT Technical Research Centre of Finland, have published their paper on the WORM memory printing process in a recent issue of Nanotechnology.The WORM memory is a resistive memory in which data is written using a high-resistive ‘0’ state and a low-resistive ‘1’ state. Readout can be performed with a device that measures the different resistances by physical contact or capacitively by sweeping over the memory without making contact. To realize a resistive WORM memory, the researchers prepared bits out of a silver nanopaste mixture that combines the advantages of two different commercial inks by Advanced Nano Products Ltd. One of the inks, called DGP, has the advantage of being writable with moderate electrical power, but has the disadvantage of instability due to the high-resistive ‘0’ state losing resistance. The second ink, called DGH, has the opposite properties: it requires a high electrical power for writing but has improved long-term stability. Although neither ink by itself is optimal for making memory bits, the researchers found that combining them offers the best of both worlds: moderate electrical power for writing and good long-term stability. (Phys.org) — In an attempt to lower the cost of making flexible write-once-read-many (WORM) memory devices, a team of researchers from Finland has developed a fabrication process that can mass-print thousands of these memories on a flexible substrate. Since they cannot be rewritten, WORM memories are particularly useful for tamper-proof applications, such as electronic voting and storing medical records. Magnetic random-access memory based on new spin transfer technology achieves higher storage density More information: Jaakko Leppäniemi, et al. “Roll-to-roll printed resistive WORM memory on a flexible substrate.” Nanotechnology 23 (2012) 305204 (12pp). DOI: 10.1088/0957-4484/23/30/305204 Citation: Roll-to-roll process prints thousands of cheap, flexible memory elements (2012, July 31) retrieved 18 August 2019 from https://phys.org/news/2012-07-roll-to-roll-thousands-cheap-flexible-memory.html When combined, the two inks form a self-organized network, which allows the researchers to tune the initial conductivity and ‘0’ state resistance of the bits. The researchers could control the resistance by controlling how sintered and close together the nanoparticles are: resistance is high when the particles are unsintered and well separated, but decreases when the particles sinter and coalesce. To control the inter-particle distance, the researchers employed nanoparticles encapsulated with ligands to prevent agglomeration and create the high-resistive ‘0’ state. To decrease the resistance, and thus switch from the ‘0’ state to the ‘1’ state, the researchers removed the encapsulation by heating with electrical current. The heat melts the ligand, which allows the unencapsulated particles to coalesce and sinter, where they achieve higher conductivity and lower resistance. (a) Illustration of the roll-to-roll printing process. After printing, the roll containing the WORM memory banks is fed into a die cutter, and some of the cut WORM memory banks are laminated. (b) VTT’s roll-to-roll printing line “ROKO.” Image credit: Leppäniemi, et al. ©2012 IOP Publishing Ltd Explore further
Chrome OS screen Pwnium is a competition to challenge the brightest minds in security to find browser vulnerabilities and attack them. They missed victory at this year’s Pwnium competition, focused on Google’s Chrome OS. As their target machine, they were given the Samsung Series 5 550 Chromebook, running the latest version of Chrome. The researchers were allowed to use any software available on the system including kernel and drivers to carry out attacks. The strings attached to the reward were that winners would have been expected to list, for Google, the vulnerabilities used in the attack, as well as any code used. Although there were no clear winners, Google said some attempts were impressive enough to merit attention. “We did not receive any winning entries but we are evaluating some work that may qualify as partial exploits.”Money paid or not, Google wins. A spokesperson said that events like this keep Chrome users safe, and also said that Google appreciated the efforts of researchers who help Google out in this safety effort.In a March 7 Google+ post, Google added, “Pwnium competitions continue to inspire us as some of the brightest minds in security show off their creativity & engineering skills. We can’t wait to see who will take home a piece of the $3.14 million ‘pi’, and help us enhance security for Chrome and the Internet overall.”In a subsequent update, when it became clear there was no winner, the Google announcement said, “We are evaluating some work that may qualify as partial exploits… see you next time!” Explore further © 2013 Phys.org Citation: Chrome OS thwarts attack attempts in Pwnium challenge (2013, March 11) retrieved 18 August 2019 from https://phys.org/news/2013-03-chrome-os-thwarts-pwnium.html More information: plus.google.com/+chrome/posts/TRotibBewk9 (Phys.org) —Hackers at a please-hack-me contest at the CanWest security conference in Vancouver, BC, went home empty-handed. The contest during the Vancouver three-day conference on digital security ended up with enlightened participants capable of attempts nonetheless missing out on a massive pile of cash—the bounty was $3.14159 million—the reward for their efforts if successful. They were unable to break into Google’s Chrome OS. This Pwnium 3 contest invited hackers to penetrate any holes they could find in the Chrome operating system. Bringing Chrome to Android more than wishful thinking 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: technicalillusions.com/www.kickstarter.com/projects/t … ile-ar-and-vr-system (Phys.org) —Hardware and software designers Jeri Ellsworth and Rick Johnson have designed what they call a projected augmented reality system—called the castAR, it appears to be unlike anything else being sold today. It’ a special pair of glasses, an infrared embedded surface and a magic wand—it allows for looking at and making changes to what looks to the user, like a holographic image. After a lot of design, testing and building, they’ve come up with a prototype that serves as the basis for a new Kickstarter project. Explore further The eyeglasses have very tiny projectors placed above each eye that project an animated image onto a special mat. A sensor just above the nose lets the system know where the person is looking and sensors in the mat keep track of where things are that are placed or moved by the person running the system. To visualize the system, imagine placing a plastic mat on the table in front of you—when you look down at it, you see a three-dimensional animated world dropping down “into” the table. To control what happens in that virtual world, you use your wand, like a mouse with a desktop computer. More impressive is that more than one person can don glasses and use the same mat at the same time—it can be shared by two people sitting across from one another—each with their own private view of the virtual world—quite naturally leading to gaming. To demonstrate, Ellsworth and Johnson set up a three dimensional version of dungeons and dragons. Adding to the surreal experience is that when players move their heads, they get a different perspective of the projected imagery, just as if they were watching something real happening on their kitchen table. It’s a truly impressive system—one that will very likely be made for sale to the public relatively soon as interest in the Kickstarter project has been pushing the dollar amount needed very quickly towards the goal of $400,000. Game system castAR debuts at Maker Faire Citation: Duo create castAR projected augmented reality system, post it on Kickstarter (2013, October 15) retrieved 18 August 2019 from https://phys.org/news/2013-10-duo-castar-augmented-reality-kickstarter.html © 2013 Phys.org The system also comes with an optional attachment for the glasses that blot out the real world allowing for a fully immersive 3D augmented reality system. Also, additional mats can be added to the system, increasing the physical size of the virtual world. Ellsworth and Johnson suggest that given the right resources, the mats could conceivably cover the floor, walls, and ceiling in a room, creating a holodeck. 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: Simultaneous submicrometric 3D imaging of the micro-vascular network and the neuronal system in a mouse spinal cord, Scientific Reports (2015) 5:8514, doi:10.1038/srep08514 Citation: Tomorrow’s tomography today: Simultaneous 3D imaging of vascular and neuronal networks in mouse spinal cord tissue (2015, March 6) retrieved 18 August 2019 from https://phys.org/news/2015-03-tomorrow-tomography-today-simultaneous-3d.html Exploring X-ray phase tomography with synchrotron radiation 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. Dr. Alessia Cedola discussed the paper that she, Dr. Michela Fratini and their co-authors published in Scientific Reports. The scientists had to address two related challenges, Cedola tells Phys.org, these being (1) showing that X-ray high-resolution phase-contrast tomography allows the simultaneous visualization of three-dimensional vascular and neuronal networks of ex vivo mouse spinal cord at scales spanning from millimeters to hundreds of nanometers without using contrast agent, sectioning, or destructive sample preparation; and (2) imaging single elements of these networks, such as microcapillaries and micrometric nerve fibers, axon-bundles and neuron soma. “Due to its potential ability to reveal the structures that generate poor contrast by common x-ray absorption techniques, we used SXrPCμT to simultaneously obtain 3D images of microvascularization and spinal cord neurology in a healthy mouse,” she explains. In fact, she notes that SXrPCμT is roughly 1,000 more sensitive to hydrogen, carbon, nitrogen, and oxygen than absorption-contrast X-ray imaging – and moreover has several additional advantages derived from its ability to provide high-resolution images that allow 3D reconstruction without damaging tissue samples.Cedola points out that better contrast can be achieved by imaging the phase modulation induced by an object in a coherent or partially coherent beam. “Different techniques have been developed to exploit phase contrast in the X-ray regime. A simple yet effective phase contrast method for hard X-rays is based upon inline imaging after free space propagation: When synchrotron X-rays illuminate the sample, variations in optical path length produce slight local deviations of the X-ray beam. In absorption radiography the detector is generally placed close enough to the sample that these variations are unnoticed – but on the contrary, when a free space propagation distance is allowed between sample and detector, the recorded image contains the information on the sample structure in the form of a pattern of interference fringes. Therefore, specific algorithms have to be used to retrieve from this pattern the morphological distribution of absorption and phase within the object.””This makes it possible image spinal cord microarchitecture and its 3D distribution – a hopeless task with conventional X-ray techniques,” Cedola continues. “In particular, the results reported in our paper are unique in that they simultaneously provide a detailed three-dimensional analysis of the microvascular network,” or μVN, “as well as the relevant interactions with neural cells in the healthy mouse’s spinal cord – and to do so without any contrast agent. Our resolution allows us to discriminate the smallest capillaries and neuronal morphology with neither invasive contrast agents nor aggressive sample preparations, thus minimizing the possibility of data misinterpretation.” The scientists then compare these results with conventional histological sections of the same sample and region. In order to unequivocally identify the microvascular network, similar samples are measured with and without a prepared contrast agent called Microfill – a lead-containing radiopaque (that is, opaque to X-rays or similar radiation) silicone rubber. When the contrast agent is not used, the μVN can be imaged with great accuracy, which in turn lets the researchers investigate its spatial distribution. Journal information: Scientific Reports (Phys.org)—Given that blood supply to the brain and spinal cord is fundamental to central nervous system (CNS) physiology and pathology, it’s not surprising that trauma and disease in spinal cord blood vessels and neurons lead to a range of neurodegenerative pathologies and other serious consequences. However, current imaging tools do not generate sufficient dimensionality, resolution, contrast and other factors critical to investigating neurodegenerative pathologies and spinal-cord-injuries, as well as to understanding the relationship between vascular and neuronal systems. Neural population investigation: a) White/grey matter interface, imaged with inverted color, of a thick slab selected in the anterior horn of the lumbar-sacral spinal cord. b) Nissl staining, c) Hematoxylin/eosin staining and d) Immunohistochemical analysis of SMI-32, a marker of motor neurons, at the white/grey matter interface of the anterior horn of the lumbar-sacral spinal cord. e) Magnification of a single neuronal cell. Zoom of image f) SMI-32 labeled cells and g) hematoxylin/eosin staining showing a single neuronal cell. Credit: Fratini, M. et al. Simultaneous submicrometric 3D imaging of the micro-vascular network and the neuronal system in a mouse spinal cord. Sci. Rep. 5, 8514; DOI:10.1038/srep08514 (2015). Copyright © 2015, Rights Managed by Nature Publishing Group. Licensed under CC BY 4.0. a) X-ray Phase Contrast Tomography reconstructed volume of 1.2 mm thick of the lumbar-sacral region of the spinal cord. The image is obtained at a spatial resolution of 0.64 mm without contrast agent at TOMCAT beamline. The inset is a sketch of the imaged volume of the spinal cord. b) Nissl staining of the lumbar-sacral spinal cord. c) Immunohistochemical analysis of SMI-32, a marker of motor neurons, in the lumbar-sacral region of the spinal cord. d) Detail of the radial vessels of one of the vascular tree penetrating the gray matter. e) Immunohistochemistry of laminin, a marker of blood vessels, in the anterior portion of the lumbar-sacral spinal cord obtained at different levels. The red arrows in a) and b) indicate the central spinal cord canal. Credit: Fratini, M. et al. Simultaneous submicrometric 3D imaging of the micro-vascular network and the neuronal system in a mouse spinal cord. Sci. Rep. 5, 8514; DOI:10.1038/srep08514 (2015). Copyright © 2015, Rights Managed by Nature Publishing Group. Licensed under CC BY 4.0. Specifically,Micrometric-scale imaging of brain tissue such as Scanning Electron Microscopy (SEM) provide 2D images of neurons or vessels, and moreover require invasive sample preparationPost-mortem techniques also use SEM, but cannot be used to perform quantitative analyses Two-photon microscopy and other more recently-introduced methods provide 3D information but have limited penetration depth and target area sizeMagnetic Resonance Imaging (MRI) or Positron Emission Tomography (PET) allow for both structural and functional imaging, but cannot investigate microvascular networks due to spatial resolution limitationsMR angiography and volumetric-computed tomography are robust 3D imaging techniques but cannot visualize small vessels Conventional X-ray angiography also has a detection limit preventing it from imaging micrometric vessels and capillariesHigh-resolution X-ray synchrotron phase contrast tomography (XSPCT) can achieve 3D imaging of microvascular networks, but to date has required a contrast agent to visualize both microcapillaries and neuron morphologyHowever, in a recent interdisciplinary multisite study conducted at the Italian National Research Council, Enrico Fermi Centre, and other sites in Italy; European Synchrotron Radiation Facility, France; Paul Scherrer Institut, Switzerland; and other research facilities, scientists demonstrated that Synchrotron X-Ray Phase Contrast Microtomography (SXrPCμT) – a combination of high-resolution X-ray Phase Contrast Tomography and the coherence of a Synchrotron X-ray source – achieves high image contrast and enables high-resolution 3D visualization of ex vivo mouse spinal cord microvascular and neuronal in the same image. (Synchrotron X-ray tomography employs phase contrast imaging to exploit a difference in the refractive index between a detail and its surroundings, which causes a phase shift between the light that travels through the sample; ex vivo refers to experimentation or measurements done in or on tissue from an organism in an external environment with the minimum alteration of natural conditions.) Moreover, SXrPCμT accomplishes this without contrast agents (thereby increasing accuracy), sectioning or destructive sample-preparation. In addition to CNS disorders and traumatic spinal cord injuries, the researchers say that their experimental approach has significant potential in the investigation of a large number of ex vivo pre-clinical studies; might benefit biomedical, pre-clinical and clinical applications; and, perhaps unexpectedly, can be applied to the study of cultural heritage, where applications could include multiscale 3D imaging of morphology of fossils, opaque amber, prehistoric bones, and the virtual unrolling of unpublished ancient fragile papyrus writings. “Thanks to the collaboration between CNR, Centro Fermi and European advanced synchrotron radiation facilities, like ID 17 at ESRF (France) and Tomcat at PSI (Switzerland), it was possible to obtain high-quality phase contrast images,” Cedola says, adding that the use of advanced techniques with synchrotron X-rays was complemented by state-of-the-art image reconstruction algorithms. “Our work focuses on an interdisciplinary research,” Cedola tells Phys.org. “We engage biomedical science and physics with the intent to focus on the translation of modern X-ray physics concepts to pre-clinical applications. In addition, we believe that our paper demonstrates the potentialities of the synchrotron X-ray phase contrast microtomography technique, showing that it can be applied to a large number of ex vivo pre-clinical studies.”In their paper, the scientists describe their approach as being very well-suited for pre-clinical investigation of neurodegenerative pathologies and spinal-cord-injuries. “Neurodegenerative diseases, such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, multiple sclerosis, and Huntington’s disease, represent a most prevalent health problem worldwide,” Cedola notes. “The main goal of this project is to develop a solid method for pre-clinical research in this field,” pointing out that there is growing interest in high-resolution imaging techniques for the investigation of several pathological markers. “Our framework allows for a direct, quantitative estimation of the most important morphological and topological parameters characterizing the vascular and neuronal networks in the spinal cord. In particular, the 3D spinal cord geometry obtained using SXrPCμT will provide an innovative framework aiding the regular application in the pre-clinical practice to, for example, select the best treatment.”The paper also addresses the various ways in which their approach can be applied to resolve the entangled relationship between vascular and neuronal systems. “Neurons, astrocytes, glia, and microvessels seem to constitute an integrated functional unit, whose primary purpose is to maintain the homeostasis of the brain’s microenvironment,” Cedola says. “Furthermore, it was found that alterations of the CNS vascular regulatory mechanisms lead to brain dysfunction and diseases, including cancer, ischemia” – in which insufficient blood flow to the brain leads to cerebral hypoxia (insufficient oxygen supply) and, in turn, neuronal cell death or stroke – “edema, damage to white matter, and other neurodegenerative pathologies. Thanks to these high-resolution techniques making it possible to simultaneously visualize the distribution and interactions of vascular and neuronal networks in various tissue types, we may finally resolve the relationship between the microvascular and neuronal systems. This promises significant progress in understanding the neuronal and vascular physiology of neurodegenerative diseases, leading advances in regenerative medicine for the treatment of traumatic spinal cord diseases.”Moving forward, Cedola tells Phys.org that the study of central nervous system disorders and traumatic spinal cord injuries are the most significant examples of the next steps we plan to take in our research. “In addition,” she continues, “the study of the spinal cord system can be of immediate and fruitful application in the medical field and in particular in the investigation and treatment of neuro-degenerative diseases, such as multiple sclerosis, and spinal cord injuries. Recently, for example,” she illustrates, “traumatic diseases of the spinal cord have been treated with regeneration methods, making evident the utility of a tool able to verify the effectiveness of treatments during the testing phase.”Looking further into the future, when asked how their research might contribute to the effort to create an integrated structural/function connectome of the entire brain, Cedola replies that “the possibility to obtain 3D quantification of the vascular and neural networks and, by means of their characteristic and real geometry using SXrPCμT and specific algorithms, will be employed to refine current vascular and neuronal models. “That said, while we’re not directly involved with efforts such as the NIH Human Connectome Project or the Harvard/MGH-UCLA consortium Human Connectome Project, we’ve used their data and collaborate with several of their members.” © 2015 Phys.org VN investigation: a) X-ray Phase Contrast Tomography reconstructed volume of lumbar-sacral region of the spinal cord. The image, obtained with a pixel size of 0.64 mm without contrast agent at TOMCAT beamline, was segmented to show the capillaries and the nerve fibers. b) Magnified region of a): the vessels are red and the nerve fibers are green. c) Immunohistochemical analysis of laminin, a marker of blood vessels, in the lumbar-sacral spinal cord showing a coronal section of the vascular system. d) Immunohistochemical analysis of myelin basic protein (MBP), a marker of the myelin sheath of nerve fibers in the spinal cord. Credit: Fratini, M. et al. Simultaneous submicrometric 3D imaging of the micro-vascular network and the neuronal system in a mouse spinal cord. Sci. Rep. 5, 8514; DOI:10.1038/srep08514 (2015). Copyright © 2015, Rights Managed by Nature Publishing Group. Licensed under CC BY 4.0. Explore further
Scientists entangling quantum particles and even whole atoms have been in the news a lot over the past couple of years, conducting experiments with the goal of attempting to better understand the strange phenomenon—and much has been learned. But as scientists figure out how to entangle two particles at ever-greater distances, there are questions about the size of objects that can be entangled. Schrödinger’s cat has come up in several such discussions as theorists and those in the applied fields seek to determine if it might be possible to cause a whole cat to occupy two places at once. In this new work, the team at Stanford has, perhaps, muddied the water even more, as they have extended the record for supposition from a mere one centimeter to just over a half-meter.They did it by creating a Bose-Einstein condensate cloud of 10,000 rubidium atoms inside of a super-chilled chamber, all initially in the same state. Next, the used lasers to push the cloud up into the 10-meter-high chamber, which also caused the atoms to enter one or the other of a given state. As the cloud reached the top of the chamber, the researchers noted that the wave function was a half-and-half mixture of the given states and represented positions that were 54 centimeters apart. When the cloud was allowed to fall back to the bottom of the chamber, the researchers confirmed that atoms appeared to have fallen from two different heights, proving that the cloud was held in a superposition state.The team acknowledges that while their experiment has led to a new record for superposition at the macroscopic scale, it still was done with individual atoms; thus, it is unclear if superposition will work with macroscopic objects. A team of researchers working at Stanford University has extended the record for quantum superposition at the macroscopic level from one to 54 centimeters. In their paper published in the journal Nature, the team describes the experiment they conducted, their results and also discuss what their findings might mean for researchers looking to find the cut-off point between superposition as it applies to macroscopic objects versus those that only exist at the quantum level. Nature has also published an editorial on the study, describing the experiment and summarizing the results. Citation: New half-meter record for quantum superposition at macroscopic level (2015, December 29) retrieved 18 August 2019 from https://phys.org/news/2015-12-half-meter-quantum-superposition-macroscopic.html © 2015 Phys.org Physicists propose measure of macroscopicity; Schrodinger’s cat scores a 57 This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further More information: T. Kovachy et al. Quantum superposition at the half-metre scale, Nature (2015). DOI: 10.1038/nature16155AbstractThe quantum superposition principle allows massive particles to be delocalized over distant positions. Though quantum mechanics has proved adept at describing the microscopic world, quantum superposition runs counter to intuitive conceptions of reality and locality when extended to the macroscopic scale1, as exemplified by the thought experiment of Schrödinger’s cat. Matter-wave interferometers, which split and recombine wave packets in order to observe interference, provide a way to probe the superposition principle on macroscopic scales4 and explore the transition to classical physics. In such experiments, large wave-packet separation is impeded by the need for long interaction times and large momentum beam splitters, which cause susceptibility to dephasing and decoherence1. Here we use light-pulse atom interferometry to realize quantum interference with wave packets separated by up to 54 centimetres on a timescale of 1 second. These results push quantum superposition into a new macroscopic regime, demonstrating that quantum superposition remains possible at the distances and timescales of everyday life. The sub-nanokelvin temperatures of the atoms and a compensation of transverse optical forces enable a large separation while maintaining an interference contrast of 28 per cent. In addition to testing the superposition principle in a new regime, large quantum superposition states are vital to exploring gravity with atom interferometers in greater detail. We anticipate that these states could be used to increase sensitivity in tests of the equivalence principle, measure the gravitational Aharonov–Bohm effect, and eventually detect gravitational waves and phase shifts associated with general relativity. Journal information: Nature Fountain interferometer. Credit: Nature (2015). DOI: 10.1038/nature16155
Kolkata: Four teenaged boys drowned in a pond at Jamuria in West Burdwan on Friday morning. Police said the victims are Raj Keshri, Aman Shaw, Prince Keshri and Om Keshri. Police said Raj and Prince were brothers and they were friends of Aman and Om. They were visiting a relative of Om where the incident took place. Police came to know from the people who had witnessed the incident that they went to take a bath in a pond in the area. Also Read – Heavy rain hits traffic, flightsTwo of them accidentally fell in the pond and the other two jumped to save them. But none of them were aware of the depth of the water body and it resulted in the incident. Locals went to the spot hearing their cry for help. They tried to save them but the boys were senseless when they were brought out of the pond. Police also went to the spot. Hundreds of people gathered around the pond.They were taken to a hospital where they were declared brought dead. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedPolice have initiated a probe in this connection and spoke to the locals.Cops are trying to find out whether there was any foul play behind the incident. A senior police officer said though nothing suspicious was found in the preliminary investigation, they are looking into all aspects of the case to ascertain whether there was any foul play behind the incident. Police have initiated a probe in this regard.
Kolkata: With continuous apathy of the Centre in addressing the problem of river bank erosion in Bengal, the Mamata Banerjee government has decided to invest Rs 107 crore to check erosion at vulnerable areas along Ganga and Padma rivers. Rajib Banerjee, the state Irrigation minister, said: “We will be investing Rs 107 crore to check erosion of the banks of river Ganga and Padma.”The work that will be carried out by investing the money, will be completed by the end of March 2019. Hundreds of people will get relieved as they would no longer have to worry about their houses getting washed away by strong currents. Also Read – Heavy rain hits traffic, flightsIt may be mentioned that in 2017-18, the state Irrigation department had invested Rs 72.1 crore to check erosion at different points along the rivers and with the investment of another Rs 107 crore, a stretch of 15 km will be concretised, so that the soil does not get eroded any more.It may be recalled that around 37 spots were identified, where erosion of river banks is a serious problem and hampers the normal lives of people.The most vulnerable points out of these spots have been identified, where the work will be carried out initially so that it doesn’t cause further loss to property as agricultural land was also washed away at many places due to erosion of river banks. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAfter completion of the concretisation and strengthening of the river banks at such vulnerable locations, the same task will also be gradually taken up elsewhere in due course of time, so the problem is ironed out at all the spots.It may be mentioned that Padma river divides Murshidabad in Bengal and Bangladesh. So, the erosion of river bank also leads to threat to national security as there have been instances when river bank close to Border Out Post (BOP) of Border Security Force was washed away. BSF jawans maintain vigil on Bangladesh on the other side of the river from the BOP. On the other hand, a stretch of river Ganga divides Malda with the neighbouring states on its west. So, erosion of river bank has come up as a serious issue, causing inconvenience to the local residents.Banerjee said: “We had approached the state government several times. But it fell on deaf ears. So, the state government has taken up the responsibility to ensure safety of the people who reside along the river, by checking possibilities of erosion.”