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Feeling extra sweaty from a summer heat wave? Don’t worry — not all your perspiration has to go to waste. In a paper publishing July 13 in the journal Joule, researchers have developed a new device that harvests energy from the sweat on — of all places — your fingertips. To date, the device is the most efficient on-body energy harvester ever invented, producing 300 millijoules (mJ) of energy per square centimeter without any mechanical energy input during a 10-hour sleep and an additional 30 mJ of energy with a single press of a finger. The authors say the device represents a significant step forward for self-sustainable wearable electronics.
“Normally, you want maximum return on investment in energy. You don’t want to expend a lot of energy through exercise to get only a little energy back,” says senior author Joseph Wang (@JWangnano), a nanoengineering professor at the University of California San Diego. “But here, we wanted to create a device adapted to daily activity that requires almost no energy investment — you can completely forget about the device and go to sleep or do desk work like typing, yet still continue to generate energy. You can call it ‘power from doing nothing.'”
Previous sweat-based energy devices required intense exercise, such as a great deal of running or biking, before the user sweated enough to activate power generation. But the large amount of energy consumed during exercise can easily cancel out the energy produced, often resulting in energy return on investment of less than 1%.
In contrast, this device falls into what the authors call the “holy grail” category of energy harvesters. Instead of relying on external, irregular sources like sunlight or movement, all it needs is finger contact to collect more than 300 mJ of energy during sleep — which the authors say is enough to power some small wearable electronics. Since no movement is needed, the ratio between harvested energy and invested energy is essentially infinite.
It may seem odd to choose fingertips as the source of this sweat over, say, the underarms, but in fact, fingertips have the highest concentration of sweat glands compared to anywhere else on the body.
“Generating more sweat at the fingers probably evolved to help us better grip things,” says first co-author Lu Yin (@YinLu_CLT), a nanoengineering PhD student working in Wang’s lab. “Sweat rates on the finger can reach as high as a few microliters per square centimeter per minute. This is significant compared to other locations on the body, where sweat rates are maybe two or three orders of magnitude smaller.”
The device the researchers developed in this study is a type of energy harvester called a biofuel cell (BFC) and is powered by lactate, a dissolved compound in sweat. From the outside, it looks like a simple piece of foam connected to a circuit with electrodes, all of which is attached to the pad of a finger. The foam is made out of carbon nanotube material, and the device also contains a hydrogel that helps maximize sweat absorption.
“The size of the device is about 1 centimeter squared. Its material is flexible as well, so you don’t need to worry about it being too rigid or feeling weird. You can comfortably wear it for an extended period of time,” says Yin.
Within the device, a series of electrochemical reactions occur. The cells are equipped with a bioenzyme on the anode that oxidizes, or removes electrons from, the lactate; the cathode is deposited with a small amount of platinum to catalyze a reduction reaction that takes the electron to turn oxygen into water. Once this happens, electrons flow from the lactate through the circuit, creating a current of electricity. This process occurs spontaneously: as long as there is lactate, no additional energy is needed to kickstart the process.
Separate from but complementary to the BFC, piezoelectric generators — which convert mechanical energy into electricity — are also attached to the device to harvest up to 20% additional energy. Relying on the natural pinching motion of fingers or everyday motions like typing, these generators helped produce additional energy from barely any work: a single press of a finger once per hour required only 0.5 mJ of energy but produced over 30 mJ of energy, a 6,000% return in investment.
The researchers were able to use the device to power effective vitamin C- and sodium-sensing systems, and they are optimistic about improving the device to have even greater abilities in the future, which might make it suitable for health and wellness applications such as glucose meters for people with diabetes. “We want to make this device more tightly integrated in wearable forms, like gloves. We’re also exploring the possibility of enabling wireless connection to mobile devices for extended continuous sensing,” Yin says.
“There’s a lot of exciting potential,” says Wang. “We have ten fingers to play with.”
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Scientists at Tokyo Institute of Technology have developed a computational method based on large-scale molecular dynamics simulations to predict the cell-membrane permeability of cyclic peptides using a supercomputer. Their protocol has exhibited promising accuracy and may become a useful tool for the design and discovery of cyclic peptide drugs, which could help us reach new therapeutic targets inside cells beyond the capabilities of conventional small-molecule drugs or antibody-based drugs.
Cyclic peptide drugs have attracted the attention of major pharmaceutical companies around the world as promising alternatives to conventional small molecule-based drugs. Through proper design, cyclic peptides can be tailored to reach specific targets inside cells, such as protein-protein interactions, which are beyond the scope of small molecules. Unfortunately, it has proven notoriously difficult to design cyclic peptides with high cell-membrane permeability — that is, cyclic peptides that can easily diffuse through the lipid bilayer that delimits the inside and outside of a cell.
In an effort to resolve this bottleneck, scientists at the Middle Molecule IT-based Drug Discovery Laboratory (MIDL) have been working on a computational method for predicting cell-membrane permeability. Established in September 2017, MIDL is one of the “Research Initiatives” at Tokyo Institute of Technology (Tokyo Tech) that goes beyond the boundaries of departments. Under the support of the Program for Building Regional Innovation Ecosystems of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), MIDL has been working with the city of Kawasaki to industrialize a framework for discovering middle molecule-based drugs — cyclic peptide drugs and nucleic acid drugs larger than conventional small-molecule drugs but smaller than antibody-based drugs — by combining computational drug design and chemical synthesis technology.
In a recent study published in the Journal of Chemical Information and Modeling, Professor Yutaka Akiyama and colleagues from MIDL and Tokyo Tech have developed a protocol for predicting the cell-membrane permeability of cyclic peptides using molecular dynamics simulations. Such simulations constitute a widely accepted computational approach for predicting and reproducing the dynamics of atoms and molecules by sequentially solving Newton’s laws of motion at short time intervals. However, even a single simulation for predicting the permeability of a cyclic peptide with only eight amino acids takes a tremendous amount of time and resources. “Our study marks the first time comprehensive simulations were performed for as many as 156 different cyclic peptides,” highlights Prof. Akiyama, “The simulation of each cyclic peptide using the protocol we developed took about 70 hours per peptide using 28 GPUs on the TSUBAME 3.0 supercomputer at Tokyo Tech.”
The researchers verified the predicted permeability values with experimentally derived ones and confirmed an acceptable correlation coefficient of R = 0.63 under the best conditions, showcasing the potential of their protocol. Moreover, after a detailed analysis of the peptide conformation and energy values obtained from the trajectory data, Prof. Akiyama’s team found that the strength of the electrostatic interactions between the atoms constituting the cyclic peptide and the surrounding media, namely lipid membrane and water molecules, are strongly related to the membrane permeability value. The simulations also revealed the way in which peptides permeate through the membrane by changing their orientation and conformation according to their surroundings. “Our results shed some light on the mechanisms of cell-membrane permeability and provide a guideline for designing molecules that can get inside cells more efficiently. This will greatly contribute to the development of next-generation peptide drugs,” remarks Prof. Masatake Sugita, the first author of the study.
The researchers are already working on a more advanced simulation protocol that will enable more accurate predictions. They are also trying to incorporate artificial intelligence into the picture by adopting deep learning techniques, which could increase both accuracy and speed. Considering that cyclic peptides could unlock many therapeutic targets for diseases that are difficult to treat, let us hope that scientists at MIDL and Tokyo Tech succeed in their endeavors!
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The absorption of energy from laser light by free electrons in a liquid has been demonstrated for the first time. Until now, this process was observed only in the gas phase. The findings, led by Graz University of Technology, open new doors for ultra-fast electron microscopy.
The investigation and development of materials crucially depends on the ability to observe smallest objects at fastest time scales. The necessary spatial resolution for investigations in the (sub-)atomic range can be achieved with electron microscopy. For the most rapid processes, however, proceeding within a few femtoseconds (quadrillionths of a second), the time resolution of conventional electron microscopes is insufficient. To improve the time duration of electron pulses, electrons would have to be selected within a shorter time window — in analogy to a camera shutter, which controls the exposure time in photography.
In principle, this temporal selection is possible with extremely short laser pulses through a process called laser-assisted electron scattering (LAES). In this process, electrons can absorb energy from the light field during collisions with atoms of the sample under investigation. “Structural information is provided by all electrons, but those that have a higher energy level can be assigned to the time window in which the light pulse was present. With this method, it is possible to select a short time window from the long electron pulse and thus improve the time resolution,” explains Markus Koch, professor at the Institute of Experimental Physics at Graz University of Technology. So far, however, LAES processes have only been observed in the gas phase, despite their investigation for about 50 years.
Markus Koch and his team, in collaboration with researchers from Photonics Institute at Vienna University of Technology and the Institute of Chemistry at Tokyo Metropolitan University, have now demonstrated for the first time that laser-assisted electron scattering can also be observed in condensed matter, specifically in superfluid helium.
Superfluid helium leading to success
The TU Graz researchers performed the experiment in a superfluid helium droplet of few nanometer diameter (3-30 nm), into which they loaded single atoms (indium or xenon) or molecules (acetone) that served as an electron source — a field of expertise at the institute. “The free electrons can move almost without friction within the droplet and absorb more energy in the light field than they lose in collisions with the helium atoms,” says Leonhard Treiber, the PhD student in charge of the experiment. The resulting acceleration allows for the observation of much faster electrons.
The experiments could be interpreted in cooperation with Markus Kitzler-Zeiler, an expert for strong-field processes at TU Wien, and the LAES process was confirmed through simulations by Reika Kanya from Tokyo Metropolitan University. The results were published in Nature Communications.
In the future, the LAES process will be studied within thin films of various materials, also produced inside helium droplets, in order to determine important parameters such as the optimal film thickness or the favourable intensity of the laser pulses for application in an electron microscope.
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Materials provided by Graz University of Technology. Original written by Christoph Pelzl. Note: Content may be edited for style and length. More

Artificial microswimmers have received much attention in recent years. By mimicking microbes which convert their surrounding energy into swimming motions, these particles could soon be exploited for many important applications. Yet before this can happen, researchers must develop methods to better control the trajectories of individual microswimmers in complex environments. In a new study published inEPJ E, Shubhadeep Mandal at the Indian Institute of Technology Guwahati (India), and Marco Mazza at the Max Planck Institute for Dynamics and Self-Organisation in Göttingen (Germany) and Loughborough University (UK), show how this control could be achieved using exotic materials named ‘nematic liquid crystals’ (LCs) — whose viscosity and elasticity can vary depending on the direction of an applied force.

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A new model tracking the vertical movement of algae-covered microplastic particles offers hope in the fight against plastic waste in our oceans.
Research led by Newcastle University’s Dr Hannah Kreczak is the first to identify the processes that underpin the trajectories of microplastics below the ocean surface. Publishing their findings in the journal Limnology and Oceanography the authors analysed how biofouling — the accumulation of algae on the surface of microplastics, impacts the vertical movement of buoyant particles.
The researchers found that particle properties are the biggest factor in determining the period and characteristics of the repetitive vertical movement below the surface, while the algal population dynamics determine the maximum depth reached. Their findings also show that the smallest particles are extremely sensitive to algal cell attachment and growth, suggesting they are always submerged at depths surrounding the base of the euphotic zone, the layer closer to the surface that receives enough light to support photosynthesis, or could become trapped in large algal colonies.
In general, the results suggest that a higher concentration of biofouled microplastic is expected to be found subsurface, close to the euphotic zone depth rather than at the ocean’s surface.
Microplastics (fragments with a diameter smaller than 5mm) make up 90% of the plastic debris found at the ocean surface and the amount of plastic entering our ocean is significantly larger than the estimates of floating plastic on the surface of the ocean. However, it is not exactly known what happens to these particles once they enter the ocean, and 99% of microplastics within our ocean are considered missing.
This new model has the potential to understand the distribution of fouled plastics in the ocean and therefore the ecological impact, particularly in areas of high concentration.
Dr Hannah Kreczak, EPSRC Doctoral Prize Fellow at Newcastle University’s School of Mathematics, Statistics and Physics, said: “Mathematical modelling has been extremely beneficial in identifying hot-spots for marine plastic pollution on the ocean surface. I hope this research can be a constructive step in understanding the impact plastic pollution has below the surface and aid in the effort towards a more sustainable ocean.”
Co-Author Dr Andrew Baggaley, Lecturer in Applied Mathematics at the School of Mathematics, Statistics and Physics, added: “This is an exciting first step in our project to develop a comprehensive modelling framework to understand the transport of microplastic particles and their distribution in the oceans.”
Future research by the team will focus on the fluid motion in the ocean mixed layer, to allow for even more complete assessment of microplastic vertical distributions in the ocean.
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Just as helicopter traffic reporters use their “bird’s eye view” to route drivers around roadblocks safely, radiation oncologists treating a variety of cancers can use new guidelines developed by a West Virginia University researcher to reduce mistakes in data transfer and more safely treat their patients.
Ramon Alfredo Siochi — the director of medical physics at WVU — led a task group to help ensure the accuracy of data that dictates a cancer patient’s radiation therapy. The measures he and his colleagues recommended in their new report safeguard against medical errors in a treatment that more than half of all cancer patients receive.
“The most common mistake that happens in radiation oncology is the transfer of information from one system to another,” Siochi, the associate chair for the School of Medicine’s Department of Radiation Oncology, said. “This report gives you a good, bird’s-eye view of the way data is moving around in your department.”
“How frequently do these accidents occur? I think one estimate I saw was that three out of every 100 patients might have an error, but it doesn’t necessarily harm them. Now, I don’t know what the incidence rate is of errors that are quote-unquote ‘near misses’ — when an error happens before it hits the patient — but I would imagine it is much higher.
Siochi recently chaired the Task Group of Quality Assurance on External Beam Treatment Data Transfer, a division of the American Association of Physicists in Medicine.
The group was formed in response to news coverage of radiation overdoses caused by faulty data transfer.
“In 2010, it was reported in the New York Times that a patient [in a New York City hospital] was overdosed with radiation because the data somehow didn’t transfer properly from one system to another,” Siochi said. “Long story short, the patient received a lethal dose of radiation to his head that went on for three days undetected. Now, that falls into the general class of many things happening that were not standard practice. But it could have been avoided.”
Radiation therapy is used to treat a variety of cancers, including cancers of the lung, pancreas, prostate, breast, brain and bladder. Depending on a cancer’s type or stage, radiation may cure it, shrink it or stop it from coming back.
But as the complexity of radiation therapy has grown — making it possible to target cancers that would once have been too difficult to treat — so too has the amount of data that goes into treatment machines. With more data comes more opportunity for errors.
When Siochi started practicing radiation oncology physics — in the 1990s — this data evoked a tree-lined residential street more than the six-lane highway it brings to mind today.
“It was very analog,” he said. “We’re talking maybe 20 parameters that you would need to check on a plan, and you would put it all on a paper chart. But I once did a calculation — to do an order of magnitude — and now we’re talking about 100,000 parameters. It’s just impossible for a human to check.”
The group’s report — which earned the approval of AAPM and the Science Council — makes that volume of parameters less overwhelming. It explains how data is transferred among various systems used in radiation therapy, and it suggests ways that medical physicists can test the data’s integrity throughout the process, contributing to safer treatments.
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A KAIST research team and collaborators revealed a newly developed hydrogel-based flexible brain-machine interface. To study the structure of the brain or to identify and treat neurological diseases, it is crucial to develop an interface that can stimulate the brain and detect its signals in real time. However, existing neural interfaces are mechanically and chemically different from real brain tissue. This causes foreign body response and forms an insulating layer (glial scar) around the interface, which shortens its lifespan.
To solve this problem, the research team of Professor Seongjun Park developed a ‘brain-mimicking interface’ by inserting a custom-made multifunctional fiber bundle into the hydrogel body. The device is composed not only of an optical fiber that controls specific nerve cells with light in order to perform optogenetic procedures, but it also has an electrode bundle to read brain signals and a microfluidic channel to deliver drugs to the brain.
The interface is easy to insert into the body when dry, as hydrogels become solid. But once in the body, the hydrogel will quickly absorb body fluids and resemble the properties of its surrounding tissues, thereby minimizing foreign body response.
The research team applied the device on animal models, and showed that it was possible to detect neural signals for up to six months, which is far beyond what had been previously recorded. It was also possible to conduct long-term optogenetic and behavioral experiments on freely moving mice with a significant reduction in foreign body responses such as glial and immunological activation compared to existing devices.
“This research is significant in that it was the first to utilize a hydrogel as part of a multifunctional neural interface probe, which increased its lifespan dramatically,” said Professor Park. “With our discovery, we look forward to advancements in research on neurological disorders like Alzheimer’s or Parkinson’s disease that require long-term observation.”
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Scientists have discovered a novel way to classify magnetized plasmas that could possibly lead to advances in harvesting on Earth the fusion energy that powers the sun and stars. The discovery by theorists at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) found that a magnetized plasma has 10 unique phases and the transitions between them might hold rich implications for practical development.
The spatial boundaries, or transitions, between different phases will support localized wave excitations, the researchers found. “These findings could lead to possible applications of these exotic excitations in space and laboratory plasmas,” said Yichen Fu, a graduate student at PPPL and lead author of a paper in Nature Communications that outlines the research. “The next step is to explore what these excitations could do and how they might be utilized.”
Possible applications
Possible applications include using the excitations to create current in magnetic fusion plasmas or facilitating plasma rotation in fusion experiments. However, “Our paper doesn’t consider any practical applications,” said physicist Hong Qin, co-author of the paper and Fu’s advisor. “The paper is the basic theory and the technology will follow the theoretical understanding.”
In fact, “the discovery of the 10 phases in plasma marks a primary development in plasma physics,” Qin said. “The first and foremost step in any scientific endeavor is to classify the objects under investigation. Any new classification scheme will lead to improvement in our theoretical understanding and subsequent advances in technology,” he said.
Qin cites discovery of the major types of diabetes as an example of the role classification plays in scientific progress. “When developing treatments for diabetes, scientists found that there were three major types,” he said. “Now medical practitioners can effectively treat diabetic patients.”
Fusion, which scientists around the world are seeking to produce on Earth, combines light elements in the form of plasma — the hot, charged state of matter composed of free electrons and atomic nuclei that makes up 99 percent of the visible universe — to release massive amounts of energy. Such energy could serve as a safe and clean source of power for generating electricity.
The plasma phases that PPPL has uncovered are technically known as “topological phases,” indicating the shapes of the waves supported by plasma. This unique property of matter was first discovered in the discipline of condensed matter physics during the 1970s — a discovery for which physicist Duncan Haldane of Princeton University shared the 2016 Nobel Prize for his pioneering work.
Robust and intrinsic
The localized plasma waves produced by phase transitions are robust and intrinsic because they are “topologically protected,” Qin said. “The discovery that this topologically protected excitation exists in magnetized plasmas is a big step forward that can be explored for practical applications,” he said.
For first author Fu, “The most important progress in the paper is looking at plasma based on its topological properties and identifying its topological phases. Based on these phases we identify the necessary and sufficient condition for the excitations of these localized waves. As for how this progress can be applied to facilitate fusion energy research, we have to find out.”
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Materials provided by DOE/Princeton Plasma Physics Laboratory. Original written by John Greenwald. Note: Content may be edited for style and length. More