The Kynix Blog

In 2014, when University of Wisconsin-Madison engineers announced in the journal Nature Communications that they had developed transparent sensors for use in imaging the brain, researchers around the world took notice.Then the requests came flooding in. "So many research groups started asking us for these devices that we couldn't keep up," says Zhenqiang (Jack) Ma, the Lynn H. Matthias Professor and Vilas Distinguished Achievement Professor in electrical and computer engineering at UW-Madison.Ma's group is a world leader in developing revolutionary flexible electronic devices. The see-through, implantable micro-electrode arrays were light years beyond anything ever created.Although he and collaborator Justin Williams, the Vilas Distinguished Achievement Professor in biomedical engineering and neurological surgery at UW-Madison, patented the technology through the Wisconsin Alumni Research Foundation, they saw its potential for advancements in research. "That little step has already resulted in an explosion of research in this field," says Williams. "We didn't want to keep this technology in our lab. We wanted to share it and expand the boundaries of its applications."As a result, in a paper published Thursday (Oct. 13, 2016) in the journal Nature Protocols, the researchers have described in great detail how to fabricate and use transparent graphene neural electrode arrays in applications in electrophysiology, fluorescent microscopy, optical coherence tomography, and optogenetics. "We described how to do these things so we can start working on the next generation," says Ma.Now, not only are the UW-Madison researchers looking at ways to improve and build upon the technology, they also are seeking to expand its applications from neuroscience into areas such as research of stroke, epilepsy, Parkinson's disease, cardiac conditions, and many others. And they hope other researchers do the same."This paper is a gateway for other groups to explore the huge potential from here," says Ma. "Our technology demonstrates one of the key in vivo applications of graphene. We expect more revolutionary research will follow in this interdisciplinary field."Reference:GP1S036PKGS-00GXP1-RRB-3R0232-50  

It's hardly a character flaw, but organic transistors—the kind envisioned for a host of flexible electronics devices—behave less than ideally, or at least not up to the standards set by their rigid, predictable silicon counterparts. When unrecognized, a new study finds, this disparity can lead to gross overestimates of charge-carrier mobility, a property key to the performance of electronic devices.If measurements fail to account for these divergent behaviors in so-called "organic field-effect transistors" (OFETs), the resulting estimates of how fast electrons or other charge carriers travel in the devices may be more than 10 times too high, report researchers from the National Institute of Standards and Technology (NIST), Wake Forest University and Penn State University. The team's measurements implicate an overlooked source of electrical resistance as the root of inaccuracies that can inflate estimates of organic semiconductor performance.Already used in light-emitting diodes, or LEDs, electrically conductive polymers and small molecules are being groomed for applications in flexible displays, flat-panel TVs, sensors, "smart" textiles, solar cells and "Internet of Things" applications. Besides flexibility, a key selling point is that the organic devices—sometimes called "plastic electronics"—can be manufactured in large volumes and far more inexpensively than today's ubiquitous silicon-based devices.A key sticking point, however, is the challenge of achieving the high levels of charge-carrier mobility that these applications require. In the semiconductor arena, the general rule is that higher mobility is always better, enabling faster, more responsive devices. So chemists have set out to hurry electrons along. Working from a large palette of organic materials, they have been searching for chemicals—alone or in combination—that will up the speed limit in their experimental devices.Just as for silicon semiconductors, assessments of performance require measurements of current and voltage. In the basic transistor design, a source electrode injects charge into the transistor channel leading to a drain electrode. In between sits a gate electrode that regulates the current in the channel by applying voltage, functioning much like a valve.Typically, measurements are analyzed according to a longstanding theory for silicon field-effect transistors. Plug in the current and voltage values and the theory can be used to predict properties that determine how well the transistor will perform in a circuit.Results are rendered as a series of "transfer curves." Of particular interest in the new study are curves showing how the drain current changes in response to a change in the gate electrode voltage. For devices with ideal behavior, this relationship provides a good measure of how fast charge carriers move through the channel to the drain."Organic semiconductors are more prone to non-ideal behavior because the relatively weak intermolecular interactions that make them attractive for low-temperature processing also limit the ability to engineer efficient contacts as one would for state-of-the-art silicon devices," says electrical engineer David Gundlach, who leads NIST's Thin Film Electronics Project. "Since there are so many different organic materials under investigation for electronics applications, we decided to step back and do a measurement check on the conventional wisdom."Using what Gundlach describes as the semiconductor industry's "workhorse" measurement methods, the team scrutinized an OFET made of single-crystal rubrene, an organic semiconductor with a molecule shaped a bit like a microscale insect. Their measurements revealed that electrical resistance at the source electrode—the contact point where current is injected into the OFET— significantly influences the subsequent flow of electrons in the transistor channel, and hence the mobility.In effect, contact resistance at the source electrode creates the equivalent of a second valve that controls the entry of current into the transistor channel. Unaccounted for in the standard theory, this valve can overwhelm the gate—the de facto¬ regulator between the source and drain in a silicon semiconductor transistor—and become the dominant influence on transistor behavior.At low gate voltages, this contact resistance at the source can overwhelm device operation. Consequently, model-based estimates of charge-carrier mobility in organic semiconductors may be more than 10 times higher than the actual value, the research team reports.Hardly ideal behavior, but the aim of the study, the researchers write, is to improve "understanding of the source of the non-ideal behavior and its impact on extracted figures of merit," especially charge-carrier mobility. This knowledge, they add, can inform efforts to develop accurate, comprehensive measurement methods for benchmarking organic semiconductor performance, as well as guide efforts to optimize contact interfaces.Reference:2SA1987C4706FJA4213RTU 

Inflammation is a good thing when it's fighting off infection, but too much can lead to autoimmune diseases or cancer. In efforts to dampen inflammation, scientists have long been interested in CC chemokine receptor 2 (CCR2)—a protein that sits on the surface of immune cells like an antenna, sensing and transmitting inflammatory signals that spur cell movement toward sites of inflammation. Researchers at the Skaggs School of Pharmacy and Pharmaceutical Sciences at University of California San Diego have now determined the 3D structure of CCR2 simultaneously bound to two inhibitors. Understanding how these molecules fit together may better enable pharmaceutical companies to develop anti-inflammatory drugs that bind and inhibit CCR2 in a similar manner.CCR2 and associated signaling molecules are known to play roles in a number of inflammatory and neurodegenerative diseases, including multiple sclerosis, asthma, diabetic nephropathy and cancer. Many drug companies have attempted to develop drugs that target CCR2, but none have yet made it to market."So far drugs that target CCR2 have consistently failed in clinical trials," said Tracy Handel, PhD, professor in the Skaggs School of Pharmacy. "One of the biggest challenges is that, to work therapeutically, CCR2 needs to be turned 'off' and stay off completely, all of the time. We can't afford ups and downs in its activity. To be effective, any small molecule drug that inhibits CCR2 would have to bind the receptor tightly and stay there. And that's difficult to do."Handel led the study with Irina Kufareva, PhD, project scientist at Skaggs School of Pharmacy, and Laura Heitman, PhD, of Leiden University. The study's first author is Yi Zheng, PhD, postdoctoral researcher also at Skaggs School of Pharmacy.CCR2 spans the membrane of immune cells. Part of the receptor sticks outside the cell and part sticks inside. Inflammatory molecules called chemokines bind the external part of CCR2 and the receptor carries that signal to the inside of the cell. Inside the cell, CCR2 changes shape and binds other communication molecules, such as G proteins, triggering a cascade of activity. As a result, the immune cells move, following chemokine trails that lead them to places in the body where help is needed.In this study, the researchers used a technique known as X-ray crystallography to determine the 3D structure of CCR2 with two molecules bound to it simultaneously—one at each end.That's a huge accomplishment because, Kufareva said, "Receptors that cross the cell membrane are notoriously hard to crystalize. To promote crystallization, we needed to alter the amino acid sequence of CCR2 to make the receptor molecules assemble in an orderly fashion. Otherwise, when taken out of the cell membrane, they tend to randomly clump together. "Handel, Kufareva and team also discovered that the two small molecules binding CCR2 turn the receptor "off" by different but mutually reinforcing mechanisms. One of the small molecules binds the outside face of the receptor and blocks binding of the natural chemokines that normally turn the receptor "on." The other small molecule binds the face of the receptor inside the cell, where the G protein normally binds, preventing inflammatory signal transmission. According to Handel, the latter binding site has never been seen before.   

At last week's IEEE International Electron Devices Meeting (IEDM) in San Francisco (USA), imec, the world-leading research and innovation hub in nano-electronics and digital technology and Holst Centre debuted a miniaturized sensor that simultaneously determines pH and chloride (Cl-)levels in fluid. This innovation is a must have for accurate long-term measurement of ion concentrations in applications such as environmental monitoring, precision agriculture and diagnostics for personalized healthcare. The sensor is an industry first and thanks to the SoC (system on chip) integration it enables massive and cost-effective deployments in Internet-of-Things (IoT) settings. Its innovative electrode design results in a similar or better performance compared to today's standard equipment for measuring single ion concentrations and allows for additional ion tests.Sensors based on ion-selective membranes are considered the gold standard to measure ion concentrations in many applications, such as water quality, agriculture, and analytical chemistry. They consist of two electrodes, the ion-sensitive electrode with the membrane (ISE) and a reference electrode (RE). When these electrodes are immersed in a fluid, a potential is generated that scales with the logarithm of the ion activity in the fluid, forming a measure for the concentration. However, the precision of the sensor depends on the long-term stability of the miniaturized RE, a challenge that has now been overcome."The common issue with such designs is the leaching of ions from the internal electrolyte, causing the sensor to drift over time," stated Marcel Zevenbergen, senior researcher at imec/Holst Centre. "To suppress such leaching, we designed and fabricated an RE with a microfluidic channel as junction and combined it with solid-state iridium oxide (IrOx) and silver chloride (AgCl) electrodes fabricated on a silicon substrate, respectively as indicating electrodes for pH and Cl-. Our tests demonstrated this to be a long-term stable solution with the sensor showing a sensitivity, accuracy and response time that are equal or better than existing solutions, while at the same time being much smaller and potentially less expensive.""We are providing groundbreaking sensing and analytics solutions for the IoT," stated John Baekelmans, Managing Director of imec in The Netherlands. "This new multi-ion sensor is one in a series that Holst Centre is currently developing with its partners to form the senses of the IoT. For each sensor, the aim is to leapfrog the current performance of the state-of-the-art sensors in a mass-producible, wireless, energy optimized and miniaturized package."Reference:ADXRS620BBGZLPY410ALTRL3GD20HTR  

An ISA100 Wireless-based field wireless vibration sensor from Yokogawa has the ability to quickly update data as well as a long battery life. ISA100 Wireless is a technology that is based on the ISA100.11a standard. It includes ISA100.11a-2011 communications, an application layer with process control industry standard objects, device descriptions and capabilities, a gateway interface, infrared provisioning, and a backbone router.By providing real-time updates on vibration levels in plant facilities, the new sensor helps users quickly detect equipment anomalies and enables predictive maintenance.With a field wireless system, plant field devices and analysers are able to communicate wirelessly with host-level monitoring and control systems.The rising need to improve productivity and enhance safety by collecting more data on plant operations is driving the demand for field wireless devices, which can be installed even in difficult to access locations.Field wireless devices have the added advantage of reducing installation costs.Vibration sensors are useful for the condition monitoring and predictive maintenance of plant machinery such as compressors, pumps, and motors.Conventional methods for monitoring vibration include the use of vibration sensors that rely on wired communications with a host system, and patrols by maintenance staff to collect vibration data.With the widening use of field wireless systems and the need to reduce installation costs, there is an increasing demand for wireless vibration sensors.Since releasing the world’s first ISA100 Wireless-based field wireless devices and wireless systems, Yokogawa has expanded its lineup of field wireless devices that measure temperature, pressure, flow rate, and the like.This new vibration sensor will meet the company’s customers’ needs for a device that can provide the quick updates on vibration levels needed to detect anomalies at an early stage.The principal components of this field wireless vibration sensor are the FN510 field wireless multifunction module, the LN01 piezoelectric type acceleration sensor, and the FN110 field wireless communication module.Via a gateway device, the FN510 uses the ISA100 Wireless communications protocol to exchange data with a host-level system such as a DCS. The data collected with this vibration sensor enables plant operators and maintenance staff to monitor vibration levels in real time. Both explosion-proof and non-explosion-proof types are available.Reference:D7E-1BU-27135-0001005447-1   

A new line of 1.85-, 2.4- and 2.92-mm waveguide-to-coax adapters offer operating ranges up to 65 GHz. Meeting the requirement for a transition from coax to waveguide, or vice versa, the adapters’ targeted applications include satellite communications, wireless communications, industrial, test and measurement, and defense systems. The new line includes 10 adapters that include millimeter-wave frequency ranges with models in the K-band (18 to 26.5 GHz) up to the V-band (50 to 65 GHz). The adapters offer VSWR as low as 1.29:1, while also providing insertion loss performance as low as 0.3 dB. Waveguide sizes available for these new models include WR-42, WR-28, WR-22, WR-19 and WR-15. The adapters feature a right-angle configuration. Those with 2.92-mm connectors use a UG-style square waveguide flange; 2.4-mm and 1.85-mm connector versions use a UG-style circular waveguide flange. Both male and female connector options are available in each frequency band. Reference:AE-SP28U1MSP-TS430PM64AAC164336