Tag Archives: #communication

Could Corals Use Sound to Communicate? (Biology)

New evidence suggests corals may have genes involved in receiving or emitting sound

Corals are part of a highly complex ecosystem, but it remains a mystery if and how they might communicate within their biological community. In a new study, researchers found evidence of sound-related genes in corals, suggesting that the marine invertebrates could use sound to interact with their surroundings.

Coral reefs make up less than 1% of the ocean floor yet support more than 25% of all marine life. Around the world, coral reefs are being threatened by climate change, ocean acidification, diseases, overfishing and pollution. A better understanding of coral communication could help inform policies that aim to protect this critical ecosystem.

“A growing number of studies have shown that trees can communicate, and that this communication is important for ecosystems such as rain forests,” said Camila Rimoldi Ibanez, a high school student in the dual enrollment program at South Florida State College. “Coral reefs are often referred to as the rainforests of the sea because of the habitat they provide for a wide variety of plants and animals. Thus, we wanted to find out how coral communicates.”

Ibanez will present the new findings at the American Society for Biochemistry and Molecular Biology annual meeting during the virtual Experimental Biology (EB) 2021 meeting, to be held April 27-30. Her mentor is James Hawker, PhD, dean of arts and sciences at South Florida State College.

Camila Rimoldi Ibanez works with extracted coral DNA in the lab. © Camila Rimoldi Ibanez and James Hawker, South Florida State College

Many organisms that live in coral reefs perceive sound and use it to find their way to the reefs. Based on this information, the researchers decided to look for the presence of genes related to the reception and/or emission of sound in the coral Cyphastrea. Using PCR amplification, the researchers found probable evidence that two of the four genes they examined may be present in coral DNA. The genes they found — TRPV and FOLH-1 — are used for sound emission or reception in sea anemones and freshwater polyps, respectively.

In addition to performing more testing, the researchers want to sequence the TRPV and FOLH-1 genes they found to add additional evidence that these genes, or genes related to them, are present in coral.

“As we learn more about the negative impacts of sound in different kinds of ecosystems, it is vital that we set policies to protect and manage human noises in natural environments,” said Ibanez. “The more we know about how corals communicate, the better we can develop restoration and conservation projects to help corals as they face bleaching epidemics and other threats.”

Camila Rimoldi Ibanez will present the findings in poster R4543 (abstract). Contact the media team for more information or to obtain a free press pass to access the meeting.

Featured image: Researchers performed PCR amplification on extracted coral DNA mixed with primers for four genes related to sound emission or reception. If a gene is present, it will be amplified by PCR and can be detected by agarose gel electrophoresis as DNA bands of a specific size. The DNA bands showed probable presence of TRPV and FOLH-1 genes in coral DNA. © Camila Rimoldi Ibanez and James Hawker, South Florida State College

Provided by Experimental Biology

Force Transmission Between Cells Orchestrates Collective Cellular Motion (Biology)

How do the billions of cells communicate in order to perform tasks? The cells exert force on their environment through movement – and in doing so, they communicate. They work as a group in order to infiltrate their environment, perform wound healing and the like. They sense the stiffness or softness of their surroundings and this helps them connect and organize their collective effort. But when the connection between cells is distrubeddisturbed, a situation just like when cancer is initiated, can appear.

Assistant Professor Amin Doostmohammadi at the Niels Bohr Institute, University of Copenhagen has investigated the mechanics of cell movement and connection in an interdisciplinary project, collaborating with biophysicists in France, Australia, and Singapore, using both computer modelling and biological experiments. The result is now published in Nature Materials.

Amin Doostmohammadi explains: “We need to understand how cells translate this “knowledge from sensing” at the individual cell level and transform it into action on the collective level. This is still kind of a black box in biology – how do cell talk to their neighbors and act as a collective?”

The force of surrounding tissue dictates cell behavior

Individual cells have a contractile mode of motion: they pull on the surface they are located on to move themselves forward. However, cells lining up cavities and surfaces in our body, like the tubes of blood vessels or the cells at the surface of organs, are able to generate extensile forces. They do the opposite, they stretch instead of contract – and they form strong connections with their neighbors. Contractile cells are able to switch to becoming extensile cells, when coming into contact with their neighbors. If, for instance, when contractile cells sense a void or an empty space, like when a wound appears, they can loosen their cell – cell connection, become more individual, and when healing the wound, they form strong connections with their neighbors again, becoming extensile, closing the gap, so to speak.

Weakening cell connection can be the hallmark of cancer initiation

The cells connect to their neighbors by adherens junctions. They connect their internal cytoskeleton to one another and become able to transmit forces through the strong contacts. “So we asked ourselves what would happen if we prohibited the cells from making this strong connection – and it turned out that extensile, strongly connected cells turned into contractile cells with weaker connections. This is significant, because the loss of this contact is the hallmark of cancer initiation. The cells losing contact start behaving more as individuals and become able to infiltrate their surroundings. This process also happens when an embryo develops, but the key difference here is that when the healthy cells have achieved their goal, like forming an organ, they go back to their original form. Cancer cells do not. They are on a one way street”, Amin Doostmohammadi says.

The basic action and reaction of cells are determined by surroundings and communication

How cells “decide” when to go from one form to another is a complicated mix of reacting to their environment, changes in the chemical composition of it, the mechanical stiffness or softness of the tissue – and many proteins in the cells are involved in the process. The key finding of this study is that this reaction to surroundings is constantly shifting: There is a constant cross-talk between cell – surroundings and cell – cell, and this is what determines the actions and reactions of the cells.

Are treatments for cancer within the scope of this new understanding in cell mechanics?

“We must always be careful, when talking about a serious and very complex disease like cancer”, Amin Doostmohammadi says. “But what we can say is that this study brings us one step closer to understanding the basic mechanics of cell behavior, when the cells go from the normal behavior to the aggressive, cancer type cell behavior. So, one of the big questions this study raises is if we might be able to target the mechanics of the cells by some form of therapy or treatment, instead of targeting the DNA or chemical composition of the cells themselves? Could we target the environment instead of the cells? This is basic research, connecting physics and biology, into the mechanics of cell behavior, based on their sensing and responding to the surroundings and coordinating their effort – our improved understanding of this may well lead to new therapies, and there are trials going on at the moment at a preliminary stage”.

Link to the scientific article: https://www.nature.com/articles/s41563-021-00919-2

Featured image: Mixed cell populations autonomously sort themselves into separate domains: islands of extensile cells with normal cell-cell contacts (purple) surrounded by contractile cells that have weakened cell-cell contacts (green). © University of Copenhagen

Reference: Balasubramaniam, L., Doostmohammadi, A., Saw, T.B. et al. Investigating the nature of active forces in tissues reveals how contractile cells can form extensile monolayers. Nat. Mater. (2021). https://doi.org/10.1038/s41563-021-00919-2

Provided by University of Copenhagen

Boosting Fiber Optics Communications With Advanced Quantum- enhanced Receiver (Engineering)

Technology could avert capacity crunch by enhancing bandwidth while reducing energy consumption

Fiber optic technology is the holy grail of high-speed, long-distance telecommunications. Still, with the continuing exponential growth of internet traffic, researchers are warning of a capacity crunch.

In AVS Quantum Science, by AIP Publishing, researchers from the National Institute of Standards and Technology and the University of Maryland show how quantum-enhanced receivers could play a critical role in addressing this challenge.

The scientists developed a method to enhance receivers based on quantum physics properties to dramatically increase network performance while significantly reducing the error bit rate (EBR) and energy consumption.

Fiber optic technology relies on receivers to detect optical signals and convert them into electrical signals. The conventional detection process, largely as a result of random light fluctuations, produces “shot noise,” which decreases detection ability and increases EBR.

To accommodate this problem, signals must continually be amplified as pulsating light becomes weaker along the optic cable, but there is a limit to maintaining adequate amplification when signals become barely perceptible.

Quantum-enhanced receivers that process up to two bits of classical information and can overcome the shot noise have been demonstrated to improve detection accuracy in laboratory environments. In these and other quantum receivers, a separate reference beam with a single-photon detection feedback is used so the reference pulse eventually cancels out the input signal to eliminate the shot noise.

The researchers’ enhanced receiver, however, can decode as many as four bits per pulse, because it does a better job in distinguishing among different input states.

To accomplish more efficient detection, they developed a modulation method and implemented a feedback algorithm that takes advantage of the exact times of single photon detection. Still, no single measurement is perfect, but the new “holistically” designed communication system yields increasingly more accurate results on average.

“We studied the theory of communications and the experimental techniques of quantum receivers to come up with a practical telecommunication protocol that takes maximal advantage of the quantum measurement,” author Sergey Polyakov said. “With our protocol, because we want the input signal to contain as few photons as possible, we maximize the chance that the reference pulse updates to the right state after the very first photon detection, so at the end of the measurement, the EBR is minimized.”

The article “Practical quantum-enhanced receivers for classical communication” is authored by Ivan Burenkov, M.V. Jabir, and Sergey V. Polyakov. The article appears in AVS Quantum Science (DOI: 10.1116/5.0036959) and can be accessed at https://aip.scitation.org/doi/10.1116/5.0036959.

Featured image: Illustration showing how single-photon detection is used for feedback. Once correct parameters for the reference beam are established, the input state is extinguished. © Ivan Burenkov

Provided by American Institute of Physics

Does Galactic Internet Exists? When Humans Could Be Able To Build Theirs? (Astronomy)

Maccone in his recent paper showed that galactic internet could be made possible by star gravitational lensing and it may already existed

Friends, according to general relativity, all stars are endowed with a powerful focusing effect called “gravitational lensing”. This means that plane electromagnetic waves reaching the proximity of a (spherical) star from a distant radio source are deflected by the star gravity field and made to focus on the opposite side, as shown in Figure 1.

Fig 1: Geometry of the Sun gravitational lens with the minimal focal length of 550 AU (= 3.17 light days = 13.75 times beyond Pluto’s orbit) and the FOCAL spacecraft position beyond the minimal focal length. © Maccone

550 AU ≈ 3.171 light days is the minimal distance from the Sun’s center that the FOCAL spacecraft must reach to get magnified pictures of sources located on the other side of the Sun with respect to the spacecraft position. Also, a simple and important consequence is that all points on the straight line beyond this minimal focal distance are foci too. In fact, the light rays passing by the Sun further than the minimum distance have smaller deflection angles and thus come together at an even greater distance from the Sun. Thus, it is not necessary to stop the FOCAL spacecraft at 550 AU. It can go on to almost any distance beyond and focalize as well or better. The further it goes beyond 550 AU the better it is, since the less distorted are the radio waves by the Sun Corona fluctuations. These are, in short, all FOCAL missions.

Now, Claudio Maccone in his recent paper, disclosed that Galactic Internet is already in existence, if all stars are exploited as gravitational lenses and was created long ago by civilizations more advanced than ours.

Recently, Maccone published two papers in which he mathematically described the “radio bridges” created by the gravitational lens of the Sun and of any nearby star like Alpha Centauri A, or Barnard’s star, or Sirius. The result is that it is indeed possible to communicate between the solar system and a nearby interstellar system with modest signal powers if two FOCAL mission as set up: 1) One by Humans at least at 550 AU from the Sun in the opposite direction to the selected star, and 2) one by ETs at the minimal focal distance of their own star in the direction opposite to the Sun. He showed that civilization much more advanced than Humans in the Galaxy might already have created such a network of cheap interstellar links: a truly GALACTIC INTERNET that Humans will be unable to access as long as they won’t have access to the magnifying power of their own star, the Sun, i.e. until they will be able to reach the minimal focal distance of 550 AU by virtue of their own FOCAL space missions.

Now, he studied another possibility: how to create the future interstellar radio links between the solar system and any future interstellar probe by utilizing the gravitational lens of the Sun as a huge antenna. In particular, he studied the Bit Error Rate (BER) across interstellar distances with and without using the gravitational lens effect of the Sun. The conclusion is that only when we will exploit the Sun as a gravitational lens we will be able to communicate with our own probes (or with nearby Aliens) across the distances of even the nearest stars to us in the Galaxy, and that at a reasonable Bit Error Rate.

He also studied the radio bridge between the Sun and any other Star that is made up by the two gravitational lenses of both the Sun and that Star. The alignment for this radio bridge to work is very strict, but the powersaving is enormous, due to the huge contributions of the two stars’ lenses to the overall antenna gain of the system (shown by me below). For instance, he studied in detail: 1) The Sun–Alpha Cen A radio bridge (2) The Sun–Barnard’s Star radio bridge (3) The Sun–Sirius A radio bridge (4) The radio Bridge between the Sun and any sun–like star located in the Galactic Bulge. (5) The radio Bridge between the Sun and a sun–like star located in the Galactic Bridge. Lets have a closer look on all these radio bridges.

1) The Sun–Alpha Cen A radio bridge

Fig 2 © Maccone

Figure 2 shows the Bit Error Rate (BER) for the double-gravitational-lens system giving the radio bridge between the Sun and Alpha Cen A. In other words, there are two gravitational lenses in the game here: the Sun one and the Alpha Cen A one, and two 12-meter FOCAL spacecrafts are supposed to have been put along the two-star axis on opposite sides at or beyond the minimal focal distances of 550 AU and 749 AU, respectively. This radio bridge has an OVERALL GAIN SO HIGH that a miserable 10¯4 watt transmitting power is sufficient to let the BER get down to zero, i.e. to have perfect telecommunications! Fantastico! Notice also that the scale of the horizontal axis is logarithmic, and the trace is yellowish since the light of Alpha Cen A is yellowish too. This will help us to distinguish this curve from the similar curve for the Barnard’s Star, that is a small red star 6 light years away, as we study next.

2) The Sun – Barnard’s Star radio bridge

Fig 3 © Maccone

Fig. 3 shows the Bit Error Rate (BER) for the double-gravitational-lens of the radio bridge between the Sun and Alpha Cen A (yellowish curve) plus the same curve for the radio bridge between the Sun and Barnard’s star (reddish curve, just as Barnard’s star is a reddish star): for it, 10¯3 watt are needed to keep the BER down to zero, because the gain of Barnard’s star is so small when compared to the Alpha Centauri A’s.

(3) The Sun–Sirius A radio bridge

Fig 4 © Maccone

Fig. 4 shows the Bit Error Rate (BER) for the double-gravitational-lens of the radio bridge between the Sun and Alpha Cen A (yellowish curve) plus the same curve for the radio bridge between the Sun and Barnard’s star (reddish curve, just as Barnard’s star is a reddish star) plus the same curve of the radio bridge between the Sun and Sirius A (blue curve, just as Sirius A is a big blue star). From this blue curve we see that only 10¯4 watt are needed to keep the BER down to zero, because the gain of Sirius A is so big when compared the gain of the Barnard’s star that it “jumps closer to Alpha Cen A’s gain” even if Sirius A is so much further out than the Barnard’s star! In other words, the star’s gain and its size combined matter even more than its distance.

(4) The radio Bridge between the Sun and any sun–like star located in the Galactic Bulge

Fig 5 © Maccone

Fig. 5 shows Bit Error Rate (BER) for the double-gravitational-lens of the radio bridge between the Sun and Alpha Cen A (orangish curve) plus the same curve for the radio bridge between the Sun and Barnard’s star (reddish curve, just as Barnard’s star is a reddish star) plus the same curve of the radio bridge between the Sun and Sirius A (blue curve, just as Sirius A is a big blue star). In addition, to the far right we now have the pink curve showing the BER for a radio bridge between the Sun and another Sun (identical in mass and size) located inside the Galactic Bulge at a distance of 26,000 light years. The radio bridge between these two Suns works and their two gravitational lenses works perfectly (i.e. BER = 0) if the transmitted power is higher than about 1000 watts.

(5) The radio Bridge between the Sun and a sun–like star located in the Galactic Bridge

Fig 6 © Maccone et al.

Fig. 6 shows the four Bit Error Rate (BER) curves plus the new cyan curve appearing here on the far right: this is the BER curve of the radio bridge between the Sun and another Sun just the same but located somewhere in the Andromeda Galaxy M 31. Notice that this radio bridge would work fine (i.e. with BER = 0) if the transmitting power was at least 107 watt = 10 Megawatt. This is not as “crazy” at it might seem if one remembers that recently the discovery of the first extrasolar planet in the Andromeda Galaxy was announced, and the method used for the detection was just GRAVITATIONAL LENSING !

Finally, he found the information channel capacity for each of the above radio bridges (shown in table 1), putting thus a physical constraint to the amount of information transfer that will be possible even by exploiting the stars as gravitational lenses.

Table 1. Channel Capacities for all five information channels made up by the radio bridges between the Sun and another star. The second and third column give the Channel Capacity for bandwidth equal to 1 Hz (typical SETI case) and 1 kHz (sometimes used in SETI also), respectively. © Maccone

Thus, author reached on conclusions:

(1) A Galactic Internet constructed by advanced Aliens by exploiting the gravitational lenses of stars may already exist in the Galaxy.

(2) The Channel Capacity for each radio bridge between any couple of communicating stars has an upper physical limit (in bits/sec), given by

{1/ln(2)} × {P_r/k_b × T_r),

where, ‘_’ is base, P_r is the received signal power, T_r is the noise temperature of the receiving antenna (radiotelescope) and k_b is Boltzmann’s constant.

3) This Galactic Internet is currently inaccessible to Humans since Humans have not yet reached the minimal focal sphere of the Sun at 550 AU (and beyond, to, say, 1000 AU) by virtue of suitable FOCAL spacecrafts.

4) Even after the focal sphere of the Sun at 550 AU will have been reached by FOCAL spacecrafts, these must be aligned with the star sending the ET signals towards the Sun. Thus, the construction of some sort of “Dyson sphere for telecommunications” around the Sun at 550 AU by future, more advanced Humans might be advisable to put us in touch with the rest of the Galaxy for the first time.

Reference: Claudio Maccone, “Galactic internet made possible by star gravitational lensing”, ArXiv, pp. 1-6, 2021. https://arxiv.org/abs/2103.11483

Copyright of this article totally belongs to our author S. Aman. One is allowed to reuse it only by giving proper credit either to him or to us

Pushed to the Limit: A CMOS-based Transceiver For Beyond 5G Applications at 300 GHz (Engineering)

Scientists at Tokyo Institute of Technology and NTT Corporation develop a novel CMOS-based transceiver for wireless communications at the 300 GHz band, enabling future beyond-5G applications. Their design addresses the challenges of operating CMOS technology at its practical limit and represents the first wideband CMOS phased-array system to operate at such elevated frequencies.

Communication at higher frequencies is a perpetually sought-after goal in electronics because of the greater data rates that would be possible and to take advantage of underutilized portions of the electromagnetic spectrum. Many applications beyond 5G, as well as the IEEE802.15.3d standard for wireless communications, call for transmitters and receivers capable of operating close to or above 300 GHz.

Unfortunately, our trusty CMOS technology is not entirely suitable for such elevated frequencies. Near 300 GHz, amplification becomes considerably difficult. Although a few CMOS-based transceivers for 300 GHz have been proposed, they either lack enough output power, can only operate in direct line-of-sight conditions, or require a large circuit area to be implemented.

To address these issues, a team of scientists from Tokyo Institute of Technology (Tokyo Tech), in collaboration with NTT Corporation (NTT), proposed an innovative design for a 300 GHz CMOS-based transceiver (Figure 1). Their work will be presented in the Digests of Technical Papers in the 2021 IEEE ISSCC (International Solid-State Circuits Conference), a conference where the latest advances in solid-state and integrated circuits are exposed.

One of the key features of the proposed design is that it is bidirectional; a great portion of the circuit, including the mixer, antennas, and local oscillator, is shared between the receiver and the transmitter (Figure 2). This means the overall circuit complexity and the total circuit area required are much lower than in unidirectional implementations.

Figure 2. Proposed bidirectional phased-array transceiver architecture © Tokyo Institute of Technology

Another important aspect is the use of four antennas in a phased array configuration. Existing solutions for 300 GHz CMOS transmitters use a single radiating element, which limits the antenna gain and the system’s output power. An additional advantage is the beamforming capability of phased arrays, which allows the device to adjust the relative phases of the antenna signals to create a combined radiation pattern with custom directionality. The antennas used are stacked “Vivaldi antennas,” which can be etched directly onto PCBs, making them easy to fabricate.

The proposed transceiver uses a subharmonic mixer, which is compatible with a bidirectional operation and requires a local oscillator with a comparatively lower frequency. However, this type of mixing results in low output power, which led the team to resort to an old yet functional technique to boost it. Professor Kenichi Okada from Tokyo Tech, who led the study, explains: “Outphasing is a method generally used to improve the efficiency of power amplifiers by enabling their operation at output powers close to the point where they no longer behave linearly—that is, without distortion. In our work, we used this approach to increase the transmitted output power by operating the mixers at their saturated output power.” Another notable feature of the new transceiver is its excellent cancellation of local oscillator feedthrough (a “leakage” from the local oscillator through the mixer and onto the output) and image frequency (a common type of interference for the method of reception used).

The entire transceiver was implemented in an area as small as 4.17 mm2. It achieved maximum rates of 26 Gbaud for transmission and 18 Gbaud for reception, outclassing most state-of-the-art solutions. Excited about the results, Okada remarks: “Our work demonstrates the first implementation of a wideband CMOS phased-array system that operates at frequencies higher than 200 GHz.” Let us hope this study helps us squeeze more juice out of CMOS technology for upcoming applications in wireless communications!

Featured image: Chip micrograph of 300 GHz-band phased-array transceiver implemented by 65 nm CMOS © Tokyo Institute of Technology

Reference: Ibrahim Abdo, Carrel da Gomez, Chun Wang, Kota Hatano, Qi Li, Chenxin Liu, Kiyoshi Yanagisawa, Ashbir Aviat Fadila, Jian Pang, Hiroshi Hamada, Hideyuki Nosaka, Atsushi Shirane, Kenichi Okada, “A 300GHz-Band Phased-Array Transceiver Using Bi-Directional Outphasing and Hartley Architecture in 65nm CMOS
[Technical paper are released at February 5 5:00 PM (PST), Live Q&As : February 17th 8:38 AM PST]”, Proceedings of the 2021 IEEE ISSCC (International Solid-State Circuits Conference), Session 22.2: Terahertz for Communication and Sensing
February 17th 8:30 AM (PST), 2021 IEEE International Solid-State Circuits Conference (ISSCC 2021) https://underline.io/log-in?eventId=74&redirectUrl=%2Fevents%2F74%2Fsessions%2F2402%2Flecture%2F13632-22.2—a-300ghz-band-phased-array-transceiver-using-bi-directional-outphasing-and-hartley-architecture-in-65nm-cmos

Provided by Tokyo Institute of Technology

What We See Shapes, What We Hear (Psychology)

People often move their hands up and down to ‘highlight’ what they are saying. Are such ‘beat gestures’ important for communication? Hans Rutger Bosker from the Max Planck Institute for Psycholinguistics and David Peeters from Tilburg University created words with an ambiguous stress pattern and asked listeners what they heard (DIScount or disCOUNT?). The beat gestures people saw influenced what they heard, showing that listeners quickly integrate verbal and visual information during speech recognition.

When politicians address an audience, they typically highlight important words with beat gestures, for example by moving their hands up and down. In fact, we all seem to do it: Such ‘flicks of the hands’ are among the most common gestures in everyday conversations. People align these gestures very precisely to the prominent words in speech. But do beat gestures help listeners to understand the speaker? Hans Rutger Bosker (Max Planck Institute for Psycholinguistics and Radboud University) and David Peeters (Tilburg University) tested whether what we see shapes what we hear.

“In face-to-face communication, language entails much more than just speech”, explains senior investigator Hans Rutger Bosker. “Speakers make use of different channels (mouth, hands, and face) to get a message across. We want to understand how listeners make use of these different streams of information when they are listening to someone.” In a well-known illusion called the ‘McGurk effect’ , people hear a sound (like the ‘b’ in ‘ba’) as a different sound (for instance ‘pa’ or ‘fa’), depending on the lip movements they see. But is there also a manual McGurk effect? Does what we hear depend on the gestures we see?

Plato or plateau?

To investigate this question, the researchers chose a set of Dutch words that differed only in stress pattern. For instance, the word “PLAto”—with stress on the first syllable—refers to the philosopher from ancient Greece. However, “plaTO”, pronounced with stress on the second syllable, refers to a plateau. Participants watched a video of Bosker producing the words (with ambiguous stress) while making beat gestures (“Now I say the word … plato”). Participants then had to decide which word they heard (PLAto or plaTEAU?). Would it matter whether beat gestures occurred at the first or second syllable?

Listeners were more likely to hear stress on a syllable if there was a beat gesture on that syllable. This ‘manual McGurk effect’ occurred for both words and non-words (“BAAGpif” or “baagPIF”?). Even more surprisingly, beat gestures influenced what vowel people heard (long or short ‘a’ in ‘baagpif / bagpif’), as vowel length is typically associated with the stress pattern of a word.

“Listeners listen not only with their ears, but also with their eyes”, says Bosker. “These findings are the first to show that beat gestures influence which speech sounds you hear”. Bosker and Peeters think that the effect of beat gestures may be even bigger in real life, when speech is less clear than in the lab. In noisy listening conditions, visual beat gestures might be even more important for successful communication. “So wash your hands, and use them”, Bosker adds jokingly.

“Our findings also have the potential to enrich human-computer interaction and improve multimodal speech recognition systems. It seems clear that such systems should take into account more than just speech”, Bosker concludes. “We will follow up on the study by using virtual reality to test how specific these effects are—are they induced by beat gestures only or also by other types of communicative cues, such as head nods and eyebrow movements.”

Reference: Hans Rutger Bosker & David Peeters, “Beat gestures influence which speech sounds you hear”, Royal Society Publishing, 2021. https://doi.org/10.1098/rspb.2020.2419 https://royalsocietypublishing.org/doi/10.1098/rspb.2020.2419

Provided by Max Planck Institute for Psycholinguistics

Newly Developed GaN based MEMS Resonator Operates Stably Even at High Temperature (Material Science)

Promising as a highly sensitive oscillator toward 5G communication.

Liwen Sang, independent scientist at International Center for Materials Nanoarchitectonics, National Institute for Materials Science (also JST PRESTO researcher) developed a MEMS resonator that stably operates even under high temperatures by regulating the strain caused by the heat from gallium nitride (GaN).

Figure 1. The device processing for the double-clamped GaN bridge resonator on Si substrate. Figure Caption: (1) The as-grown GaN epitaxial film on Si substrate. Except for the AlN buffer layer, no strain removal layer is used. (2) Spin coating of the photoresist on the GaN-on-Si sample. (3) Laser lithography to define the pattern for the double clamped bridge configuration. (4) Plasma etching to remove the GaN layer without photo resist. (5) Chemical etching to release Si under the GaN layer. Therefore, the air gap is formed. (6) The final device structure of the double clamped bridge resonator. We use the laser doppler method to measure the frequency shift and resolution under different temperatures. © Liwen Sang

High-precision synchronization is required for the fifth generation mobile communication system (5G) with a high speed and large capacity. To that end, a high-performance frequency reference oscillator which can balance the temporal stability and temporal resolution is necessary as a timing device to generate signals on a fixed cycle. The conventional quartz resonator as the oscillator has the poor integration capability and its application is limited. Although a micro-electromechanical system (MEMS)*1 resonator can achieve a high temporal resolution with small phase noise and superior integration capability, the silicon (Si)-based MEMS suffers from a bad stability at higher temperatures.

In the present study, a high-quality GaN epitaxial film was fabricated on a Si substrate using metal organic chemical vapor deposition (MOCVD)*2 to fabricate the GaN resonator. The strain engineering was proposed to improve the temporal performance. The strain was achieved through utilizing the lattice mismatch and thermal mismatch between GaN and Si substrate. Therefore, GaN was directly grown on Si without any strain-removal layer. By optimizing the temperature decrease method during MOCVD growth, there was no crack observed on GaN and its crystalline quality is comparable to that obtained by the conventional method of using a superlattice strain-removal layer.

Figure 2. (a) The temperature coefficient of frequency (TCF) of the GaN resonator at different temperature; (b) The quality factor of the GaN resonator at different temperature
The temporal stability of a resonator is defined by temperature coefficient of frequency (TCF). TCF indicates a change of the resonance frequency with changing temperature. For the Si MEMS resonator, its intrinsic TCF is ~ -30ppm/K. Several methods were proposed to reduce the TCF of Si resonator, but the quality factors of the system were greatly degraded. The quality factor of a resonator in the system can be used to determine the frequency resolution. A high quality factor is required for the accurate frequency reference. The developed GaN resonator in this work can simultaneously achieve a low TCF and high quality factor up to 600 K. The TCF is as low as -5 ppm/K. The quality factor is more than 105, which is the highest one ever reported in GaN system. © Liwen Sang

The developed GaN-based MEMS resonator was verified to operate stably even at 600K. It showed a high temporal resolution and good temporal stability with little frequency shift when the temperature was increased. This is because the internal thermal strain compensated the frequency shift and reduce the energy dissipation. Since the device is small, highly sensitive and can be integrated with CMOS technology, it is promising for the application to 5G communication, IoT timing device, on-vehicle applications, and advanced driver assistance system.

The research was supported by JST’s Strategic Basic Research Program, Precursory Research for Embryonic Science and Technology(PRESTO). This result was presented at the IEEE International Electron Devices Meeting (IEDM2020) held online on December 12-18, 2020, titled “Self-Temperature-Compensated GaN MEMS Resonators through Strain Engineering up to 600 K.”

(1) Micro-electro mechanical systems (MEMS)

A device where mechanical components, sensors, actuators, and electrical circuit are integrated on a substrate, such as semiconductor, glass, or organic material through microfabrication technology. For the main component, three-dimensional shape and movable structures are built through etching.

(2) Metal organic chemical vapor deposition (MOCVD)

A useful crystal growth method to build a wafer for compound semiconductors. Organometallic compounds of the Group III and Group V are simultaneously provided to the heated crystalline surface of the substrate to achieve epitaxial growth.

Provided by Japan Science and Technology Agency

Designer Cytokine Makes Paralyzed Mice Walk Again (Medicine)

Using gene therapy, a research team has succeeded for the first time in getting mice to walk again after a complete cross-sectional injury. The nerve cells produced the curative protein themselves.

Two to three weeks after treatment, the previously paralyzed mice began to walk.  © Lehrstuhl für Zellphysiologie

To date, paralysis resulting from spinal cord damage has been irreparable. With a new therapeutic approach, scientists from the Department for Cell Physiology at Ruhr-Universität Bochum (RUB) headed by Professor Dietmar Fischer have succeeded for the first time in getting paralyzed mice to walk again. The keys to this are the protein hyper-interleukin-6, which stimulates nerve cells to regenerate, and the way how it is supplied to the animals. The researchers published their report in the Journal Nature Communications from15 January 2021.

When the communication breaks down

Spinal cord injuries caused by sports or traffic accidents often result in permanent disabilities such as paraplegia. This is caused by damage to nerve fibers, so-called axons, which carry information from the brain to the muscles and back from the skin and muscles. If these fibers are damaged due to injury or illness, this communication is interrupted. Since severed axons in the spinal cord can’t grow back, the patients suffer from paralysis and numbness for life. To date, there are still no treatment options that could restore the lost functions in affected patients.

Designer protein stimulates regeneration

In their search for potential therapeutic approaches, the Bochum team has been working with the protein hyper-interleukin-6. “This is a so-called designer cytokine, which means it doesn’t occur like this in nature and has to be produced using genetic engineering,” explains Dietmar Fischer. His research group already demonstrated in a previous study that hIL-6 can efficiently stimulate the regeneration of nerve cells in the visual system.

In their current study, the Bochum team induced nerve cells of the motor-sensory cortex to produce hyper-Interleukin-6 themselves. For this purpose, they used viruses suitable for gene therapy, which they injected into an easily accessible brain area. There, the viruses deliver the blueprint for the production of the protein to specific nerve cells, so-called motoneurons. Since these cells are also linked via axonal side branches to other nerve cells in other brain areas that are important for movement processes such as walking, the hyper-interleukin-6 was also transported directly to these otherwise difficult to access essential nerve cells and released there in a controlled manner.

Applied in one area, effective in several areas

“Thus, gene therapy treatment of only a few nerve cells stimulated the axonal regeneration of various nerve cells in the brain and several motor tracts in the spinal cord simultaneously,” points out Dietmar Fischer. “Ultimately, this enabled the previously paralyzed animals that received this treatment to start walking after two to three weeks. This came as a great surprise to us at the beginning, as it had never been shown to be possible before after full paraplegia.”

The research team is now investigating to what extent this or similar approaches can be combined with other measures to optimize the administration of hyper-Interleukin-6 further and achieve additional functional improvements. They are also exploring whether hyper-interleukin-6 still has positive effects in mice, even if the injury occurred several weeks previously. “This aspect would be particularly relevant for application in humans,” stresses Fischer. “We are now breaking new scientific ground. These further experiments will show, among other things, whether it will be possible to transfer these new approaches to humans in the future.”


The German Research Foundation funded the study.

Reference: Marco Leibinger, Charlotte Zeitler, Philipp Gobrecht, Anastasia Andreadaki, Günter Gisselmann, Dietmar Fischer: Transneuronal delivery of hyper-IL-6 enables functional recovery after severe spinal cord injury in mice, in: Nature Communications, 2021, DOI: 10.1038/s41467-020-20112-4 https://www.nature.com/articles/s41467-020-20112-4.epdf?sharing_token=1L_RjSE659ZFb7yqsUGy-NRgN0jAjWel9jnR3ZoTv0OD8EQi1GjIW5gGDxjo-0Niib1_NxvZ9syX2oTgThU9LWEQ_SWzZNz2uSgzH2N0AJC0VcKPe9iU22saALcedvJ7aBE8dqO_QM6HgFKw0lGYYA2kTzGarGG0L_7RQ-TKF_w%3D

Provided by Ruhr Universität Bochum

First Measurement Device Independent Quantum Key Distribution Experiment to Secure Communication (Physics)

PAN Jianwei and colleagues PENG Chengzhi and ZHANG Qiang, from University of Science and Technology of China of the Chinese Academy of Sciences (CAS), collaborating with WANG Xiangbin from Tsinghua University and YOU Lixing from Shanghai Institute of Microsystems of CAS, realized the measurement device independent quantum key distribution (MDI-QKD) experiment based on long-distance free space channel for the first time. The study was published online in Physics Review Letter.

Experiment setup. It shows the top view of the experimental layout at the Pudong area, Shanghai. (Image by CAO Yuan et al.) 

Due to the fact that the atmospheric turbulence in free space channel destroys the spatial mode, it is necessary to use single-mode optical fiber for spatial filtering before interferometry. The low coupling efficiency and intensity fluctuation are the two major difficulties in this experiment.

The researchers in this study developed an adaptive optics system with strong turbulence resistance based on the stochastic gradient descent algorithm, which improved the total channel efficiency of dual links by about 4~10 times.

The rapid fluctuation of light intensity challenges clock synchronization and optical frequency comparison methods in the traditional optical fiber system to apply.

To tackle the synchronization problem, the researchers adopted a super stable crystal oscillator as the independent clock source at three experimental points and measuring the real-time feedback of the pulse arrival time, which achieves am accuracy of 32 ps.

The hydrogen cyanide molecular absorption cell was deployed at the both coding ends to calibrate the optical frequency and assured the frequency difference of the interference light was less than 10 MHz, achieving frequency locking.

The above breakthroughs helped to realize the first free space MDI-QKD experiment in Shanghai urban atmospheric channel. The length of the two channels is 7.7 km and 11.5 km respectively and the distance between two communication ends is 19.2 km.

This study provides the possibility of realizing more complex quantum information processing tasks based on long-distance quantum interference in free space channel. It is one step closer to “a global internet invulnerable to hackers may be a ways off,” according to an article published in the website of American Physical Society.

Reference: Yuan Cao, Yu-Huai Li, Kui-Xing Yang, Yang-Fan Jiang, Shuang-Lin Li, Xiao-Long Hu, Maimaiti Abulizi, Cheng-Long Li, Weijun Zhang, Qi-Chao Sun, Wei-Yue Liu, Xiao Jiang, Sheng-Kai Liao, Ji-Gang Ren, Hao Li, Lixing You, Zhen Wang, Juan Yin, Chao-Yang Lu, Xiang-Bin Wang, Qiang Zhang, Cheng-Zhi Peng, and Jian-Wei Pan, “Long-Distance Free-Space Measurement-Device-Independent Quantum Key Distribution”, Phys. Rev. Lett. 125, 260503 – Published 23 December 2020. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.125.260503

Provided by Chinese Academy of Sciences