Tech

Scientists at the University of Southampton and University of Edinburgh have developed a flexible underwater robot that can propel itself through water in the same style as nature's most efficient swimmer - the Aurelia aurita jellyfish.

The findings, published in Science Robotics, demonstrate that the new underwater robot can swim as quickly and efficiently as the squid and jellyfish which inspired its design, potentially unlocking new possibilities for underwater exploration with its lightweight design and soft exterior.

Co-author Dr Francesco Giorgio-Serchi, Lecturer and Chancellor's Fellow, at the School of Engineering, University of Edinburgh, said: "The fascination for organisms such as squid, jellyfish and octopuses has been growing enormously because they are quite unique in that their lack of supportive skeletal structure does not prevent them from outstanding feats of swimming."

The "cost of transport" is used to compare efficiencies of species across biology, and by this measure the jellyfish is the most efficient animal in nature, easily beating running and flying animals and bony fish.

The new robot was developed at the University of Southampton and is the first submersible to demonstrate the benefits of using resonance for underwater propulsion. Resonance refers to large vibrations that occur when applying a force at the ideal frequency, like pushing a child on a swing. This allows the robot to use very little power but generate large water jets to push itself forward.

The simple but effective mechanism consists of rubber membrane enclosing eight 3D-printed flexible ribs, which together form a 'propulsive bell'. A small piston in the top half of the robot taps this bell repeatedly so that it expands and then springs back. This mimics a jellyfish's swimming technique and produced the jets of fluid to propel the robot through the water. When the piston operates at with the correct frequency - the natural resonance for the components - the robot can move at one body length per second and match the efficiency of the Aurella aurita jellyfish.

The latest tests show the new robot is ten to fifty times more efficient than typical small underwater vehicles powered by propellers. This increased efficiency, combined with the additional benefits of the robot's soft, flexible exterior would make it ideal for operating near sensitive environments such as a coral reef, archaeological sites, or even in waters crowded with swimmers.

Co-author Thierry Bujard, a Masters student in Naval Architecture at the University of Southampton, designed and built the robot in a matter of months. Thierry said, "Previous attempts to propel underwater robots with jetting systems have involved pushing water through a rigid tube but we wanted to take it further so we brought in elasticity and resonance to mimic biology. I was really surprised by the results, I was confident that the design would work but the efficiency of the robot was much greater than I expected."

Dr Gabriel Weymouth, Associate Professor in the University's School of Engineering, who supervised the project added, "The great thing about using resonance is that we can achieve large vibrations of the propulsive bell with a very small amount of power; we just need to poke it out of shape and let the elasticity and inertia do the rest. This has allowed us to unlock the efficiency of propulsion used by sea creatures that use jets to swim.

"The last decade has seen a surge in research into flexible and biologically-inspired robots, such as Boston Dynamic's "Big Dog", because they can be much more versatile than standard industry robots. This research demonstrates that these concepts can also be applied to underwater robotics.

"There are still many challenges and exciting possibilities to explore with soft underwater robotic technologies. We are now looking to extend the concept behind this robot to a fully manoeuvrable and autonomous underwater vehicle capable of sensing and navigating its environment."

Over the past 20 years, scientists have been developing metamaterials, or materials that don't occur naturally and whose mechanical properties result from their designed structure rather than their chemical composition. They allow researchers to create materials with specific properties and shapes. Metamaterials are still not widely used in everyday objects, but that could soon change. Tian Chen, a post-doc at two EPFL labs - the Flexible Structures Laboratory, headed by Pedro Reis, and the Geometric Computing Laboratory, headed by Mark Pauly - has taken metamaterials one step further, developing one whose mechanical properties can be reprogrammed after the material has been made. His research appears in Nature.

A single material with several mechanical functions

"I wondered if there was a way to change the internal geometry of a material's structure after it's been created," says Chen. "The idea was to develop a single material that can display a range of physical properties, like stiffness and strength, so that materials don't have to be replaced each time. For example, when you twist your ankle, you initially have to wear a stiff splint to hold the ankle in place. Then as it heals, you can switch to a more flexible one. Today you have to replace the entire splint, but the hope is that one day, a single material can serve both functions."

Silicon and magnetic powder

Chen's metamaterial is made of silicon and magnetic powder and has a complicated structure that allows mechanical properties to vary. Each cell within the structure behaves like an electrical switch. "You can activate and deactivate individual cells by applying a magnetic field. That modifies the internal state of the metamaterial, and consequently its mechanical properties," says Chen. He explains that his programmable material is analogous to computer devices like hard drives. These devices contain bits of data that can be written to and read from in real time. The cells in his programmable metamaterial, called m-bits, work like the bits in a hard drive - they can be switched on, making the material stiffer, or off, making it more flexible. And researchers can program various combinations of on and off to give the material exactly the mechanical properties they need at any given time.

To develop his material, Chen drew on methods from both computer science and mechanical engineering. "That's what makes his project so special," says Pauly. Chen also spent a considerable amount of time testing his material in each of its different states. He found that it could indeed be programmed to achieve various degrees of stiffness, deformation and strength.

Many research horizons

Programmable metamaterials are akin to machines, such as robots, that employ complicated, energy-intensive electronic mechanisms. With his research, Chen aims to find the right balance between static materials and machines. Reis sees a lot of potential for further research using Chen's technology. "We could design a method for creating 3D structures, since what we've done so far is only in 2D," Reis says. "Or we could shrink the scale to make even smaller metamaterials." Chen's discovery marks a fundamental step forward, as it is the first time scientists have developed a truly reprogrammable mechanical metamaterial. It opens up many exciting avenues for research and cutting-edge industrial applications.

There are high hopes for the next generation of high energy-density lithium metal batteries, but before they can be used in our vehicles, there are crucial problems to solve. An international research team led by Chalmers University of Technology, Sweden, has now developed concrete guidelines for how the batteries should be charged and operated, maximising efficiency while minimising the risk of short circuits.

Lithium metal batteries are one of several promising concepts that could eventually replace the lithium-ion batteries which are currently widely used - particularly in various types of electric vehicles.

The big advantage of this new battery type is that the energy density can be significantly higher. This is because one electrode of a battery cell - the anode - consists of a thin foil of lithium metal, instead of graphite, as is the case in lithium-ion batteries. Without graphite, the proportion of active material in the battery cell is much higher, increasing energy density and reducing weight. Using lithium metal as the anode also makes it possible to use high-capacity materials at the other electrode - the cathode. This can result in cells with three to five times the current level of energy-density.

The big problem, however, is safety. In two recently published scientific articles in the prestigious journals Advanced Energy Materials and Advanced Science, researchers from Chalmers University of Technology, together with colleagues in Russia, China and Korea, now present a method for using the lithium metal in an optimal and safe way. It results from designing the battery in such a way that, during the charging process, the metal does not develop the sharp, needle-like structures known as dendrites, which can cause short circuits, and, in the worst cases, lead to the battery catching fire. Safety during charging and discharging is the key factor.

"Short circuiting in lithium metal batteries usually occurs due to the metal depositing unevenly during the charging cycle and the formation of dendrites on the anode. These protruding needles cause the anode and the cathode to come into direct contact with one another, so preventing their formation is therefore crucial. Our guidance can now contribute to this," says researcher Shizhao Xiong at the Department of Physics at Chalmers.

There are a number of different factors that control how the lithium is distributed on the anode. In the electrochemical process that occurs during charging, the structure of the lithium metal is mainly affected by the current density, temperature and concentration of ions in the electrolyte.

The researchers used simulations and experiments to determine how the charge can be optimised based on these parameters. The purpose is to create a dense, ideal structure on the lithium metal anode.

"Getting the ions in the electrolyte to arrange themselves exactly right when they become lithium atoms during charging is a difficult challenge. Our new knowledge about how to control the process under different conditions can contribute to safer and more efficient lithium metal batteries," says Professor Aleksandar Matic from Chalmers' Department of Physics.

In the strawberry nursery industry, a nursery's reputation relies on their ability to produce disease- and insect-free plants. The best way to produce clean plants is to start with clean planting stock. Many nurseries struggle with angular leaf spot of strawberry, a serious disease that can result in severe losses either by directly damaging the plant or indirectly through a violation of quarantine standards within the industry.

Angular leaf spot is caused by the bacterial pathogen Xanthomonas fragariae. Current management strategies rely primarily on the application of copper compounds after planting. Aside that these compounds are not applied until after the pathogen has had some time to establish, these products are also short-lived and can result in phytotoxicity.

Heat is another technique used to kill pathogens in plants and is typically applied prior to planting when the pathogen population is presumably at its lowest. However, heat treatments are often too harsh on plants, stunting their growth or killing them. Heat can also further spread pathogens if applied as a hot water treatment.

"One of the main problems with using heat to treat plants is that the temperature is also damaging to the tissues of most plants," explained Bill Turechek, a plant pathologist at the USDA in Florida. "This is why heat treatments are most often applied as seed treatments or on dormant woody tissues that tend to be more tolerant of the treatment."

Turechek and colleagues set out to develop a new heat-based treatment that would kill pathogens without hurting the plant. When asked what most excited them about their research and their new method, Turechek responded, "That it works! By introducing a lower-temperature conditioning step and using steam rather than hot water, we produced plants that were better able to withstand the higher temperature treatment designed to destroy the pathogen."

The new method uniquely uses a two-step process. The first step is a conditioning heat treatment that induces production of protective proteins and other molecules in the plant. The second step involves the application of a lethal temperature that kills the pathogen while doing little damage to the plant. This method, which applies heat via aerated steam, also reduces the spread of pathogens that might not have been killed in hot water treatments and subsequently dispersed in the bath water.

For the strawberry industry, this new method provides a safe way to eliminate pathogens and pests and should result in reduced pesticide applications and increased fruit quality and yield.

While this method was designed to target the pathogen that causes angular leaf spot, it has been shown to be effective against fungal pathogens, some nematodes, and insect pests.

"In other words, this treatment looks to have a broad spectrum of activity against numerous microbial, insect, and mite pests," Turechek explained. This protocol should be applicable to many other commodities.

A new type of ultra-efficient, nano-thin material could advance self-powered electronics, wearable technologies and even deliver pacemakers powered by heart beats.

The flexible and printable piezoelectric material, which can convert mechanical pressure into electrical energy, has been developed by an Australian research team led by RMIT University.

It is 100,000 times thinner than a human hair and 800% more efficient than other piezoelectrics based on similar non-toxic materials.

Importantly, researchers say it can be easily fabricated through a cost-effective and commercially scalable method, using liquid metals.

Lead researcher Dr Nasir Mahmood said the material, detailed in a new Materials Today study, was a major step towards realising the full potential of motion-driven, energy-harvesting devices.

"Until now, the best performing nano-thin piezoelectrics have been based on lead, a toxic material that is not suitable for biomedical use," Mahmood, a Vice-Chancellor's Research Fellow at RMIT, said.

"Our new material is based on non-toxic zinc oxide, which is also lightweight and compatible with silicon, making it easy to integrate into current electronics.

"It's so efficient that all you need is a single 1.1 nanometre layer of our material to produce all the energy required for a fully self-powering nanodevice."

The material's potential biomedical applications include internal biosensors and self-powering biotechnologies, such as devices that convert blood pressure into a power source for pacemakers.

The nano-thin piezoelectrics could also be used in the development of smart oscillation sensors to detect faults in infrastructure like buildings and bridges, especially in earthquake-prone regions.

Examples of energy-harvesting technologies that could be delivered by integrating the new material include smart running shoes for charging mobile phones and smart footpaths that harness energy from footsteps.

Flexible nanogenerator: how the material is made

The new material is produced using a liquid metal printing approach, pioneered at RMIT.

Zinc oxide is first heated until it becomes liquid. This liquid metal, once exposed to oxygen, forms a nano-thin layer on top - like the skin on heated milk when it cools.

The metal is then rolled over a surface, to print off nano-thin sheets of the zinc oxide "skin".

The innovative technique can rapidly produce large-scale sheets of the material and is compatible with any manufacturing process, including roll-to-roll (R2R) processing.

The researchers are now working on ultrasonic detectors for use in defence and infrastructure monitoring, as well as investigating the development of nanogenerators for harvesting mechanical energy.

"We're keen to explore commercial collaboration opportunities and work with relevant industries to bring future power-generating nanodevices to market," Mahmood said.

A research team led by Nagoya University in Japan has found that blood pressure, the hematocrit (the percentage of red blood cells in blood), and serum cholesterol levels change in patients with Parkinson's disease long before the onset of motor symptoms. This finding, which was recently published online in Scientific Reports, may pave the way for early diagnosis and treatment of the disease.

Parkinson's disease, the second most common disease affecting the nervous system after Alzheimer's disease, is caused by a deficiency in a neurotransmitter called dopamine. It is known that more than half of all dopaminergic neurons are already lost in patients with Parkinson's disease in the stage wherein they experience motor symptoms such as tremors, stiffness, and slowness of movement. In addition, previous studies have shown that non-motor symptoms, such as constipation, rapid eye movement sleep behavior disorder, impairment of the sense of smell, and depression, emerge in patients with Parkinson's disease10 to 20 years before the onset of motor symptoms.

These results suggest that Parkinson's disease develops decades before the onset of motor symptoms. "If we can detect biological changes in the patients' bodies well before the onset of the motor symptoms, we can start medical treatments in an early stage," says Professor Masahisa Katsuno of the Graduate School of Medicine at Nagoya University. From this perspective, the research team led by Prof. Katsuno and Katsunori Yokoi, the lead author and graduate student at Nagoya University, focused on the results of general health checkups, which are carried out among individuals yearly in Japan.

The team analyzed multiple years of data from the checkups of 22 male and 23 female patients with Parkinson's disease whose checkup results before the onset of motor symptoms were available. For comparison, the team also used data from the checkups of 60 male and 60 female healthy individuals who underwent checkups for at least four years.

The researchers first compared the baseline values of each checkup item between patients with Parkinson's disease and healthy individuals separately by sex. In male patients, the weight, body mass index, hematocrit, total and low-density cholesterol levels, and serum creatinine levels were lower than those in healthy male individuals. In female patients, the levels of blood pressure and an enzyme called aspartate aminotransferase were higher, while other items' values were lower compared to those in healthy female individuals.

Next, the researchers examined longitudinal changes in the checkup items in patients with Parkinson's disease before the onset of motor symptoms. As a result, they found that in the premotor stage, blood pressure levels are increased in female patients, whereas total and low-density cholesterol levels and the hematocrit are decreased in male patients. Regarding other checkup items, no significant changes were observed.

"In this study, we found that blood pressure, hematocrit, and serum cholesterol levels are potential biomarkers of Parkinson's disease before the onset of its motor symptoms," says Prof. Katsuno. "This finding indicates that general health checkups can help detect early signs of developing Parkinson's disease." In this context, his team is now pursuing studies to identify individuals who are at high risk for the disease based on checkup examinees. "We are also conducting clinical trials of medication in the individuals who are considered, based on their checkup data, to be at high risk for Parkinson's, in an attempt to prevent the development of the disease in them."

India has an energy problem. It currently relies heavily on coal and consumer demand is expected to double by 2040, making its green energy targets look out of reach. Part of the solution could come from harvesting energy from footsteps, say Hari Anand and Binod Kumar Singh from the University of Petroleum and Energy Studies in Dehradun, India. Their new study, published in the De Gruyter journal Energy Harvesting and Systems, shows that Indian attitudes towards power generated through piezoelectric tiles are overwhelmingly positive.

Cities like Delhi and Mumbai are famously crowded, especially at railway stations, temples and big commercial buildings. This led researchers to wonder whether piezoelectric tiles, which produce energy through mechanical pressure, could turn this footfall into something useful.

Piezoelectric tiles are made using special materials, such as crystals and ceramics, in which electric charge builds up when mechanical stress is applied - such as a foot pressing down.

Anand and Singh ran a survey in which they explored how people in India view the reliability of their household power and what their attitudes were towards generating their own electricity. They also asked participants how much they walked on average and whether they would consider implementing piezoelectric tiles into their homes.

They found that more than one in five people suffered frequent power-cuts in their area, highlighting the potential benefits of household energy generators such a piezoelectric tiles. Around 40% of respondents said they walked for more than three hours a day, and roughly 70% were willing to produce their own electricity using their feet.

The researchers also suggest that while household tiles can be used to solve problems of energy reliability and generation for individual families, piezoelectric tiles will also be a good investment for public or commercial areas with heavy footfall. They estimate that for the cost of a single 1 kW solar panel, three times more power could be generated a year using piezoelectric tiles.

"As a gadget, the piezoelectric tiles can be attractive home décor that will also help in producing household electricity," says Singh. "In this paper the output generated through the piezoelectric tiles has been studied in comparison with solar power generation."

As the efficiency and durability of piezoelectric tiles improve and as the need for green solutions becomes more urgent, the researchers predict that this type of energy production will experience a boom on the green energy market.

Whether consciously or unconsciously, automotive firms time their product recalls to minimize stock price penalties, resulting in unnecessary delays and clusters of subsequent recalls by other companies, according to new research from the University of Notre Dame.

An initial recall by one firm prompts clusters of additional recalls in close proximity by competitor firms, according to "Hiding in the Herd: The Product Recall Clustering Phenomenon," forthcoming in Manufacturing and Service Operations Management from Kaitlin Wowak, assistant professor of IT, analytics, and operations at Notre Dame's Mendoza College of Business.

According to the study, "Automobile recalls seem to be announced after inexplicable delays. Toyota's unintended acceleration recall and General Motors' (GM) ignition switch recall are two noteworthy examples, which were associated with 37 and 124 deaths, respectively. In both cases, consumers' lives were put at risk while firms hesitated to announce a recall, even after they were aware of the serious product defects. This study offers one potential explanation for recall delays: recall clustering."

The researchers analyzed 3,117 auto recalls over a 48-year period (1966-2013) using a model to investigate recall clustering, while categorizing recalls as leading or following within a cluster.

"We show that 73 percent of announced recalls within those 48 years occurred in clusters," Wowak said. "On average, a recall cluster forms after a 16-day gap in which no recalls are announced. Clusters persist for 34 days and consist of 7.6 following recalls."

The study states, "On August 21, 2017, Ford announced a recall due to leaky fuel tank valves, which was quickly followed in the subsequent days by a fuel tank recall from Honda and an oil hose recall from Chrysler. Similar groupings of recall announcements by competitors in close temporal proximity have been covered extensively by the popular press. This suggests that recall announcements may not be triggered solely by individual firms' product quality defect awareness, but may also be influenced by competitor recalls, a phenomenon that to our knowledge no prior research has investigated."

The team also found significant stock penalties associated with being the first to recall.

"Leading recalls are associated with as high as a 67 percent larger stock market penalty than following recalls," Wowak explained. "The market penalty for a following recall shortly after the leading recall is less than the market penalty for a following recall towards the end of the cluster. And the stock market penalty faced by a leading recall grows as the time since the end of the last cluster increases. That is, as the time between the last following recall of one cluster and the leading recall of the subsequent cluster increases, so too does the market penalty for the leading recall of the subsequent cluster."

The study examined how the National Highway Traffic Safety Administration (NHTSA) manages recalls compared to another major U.S. regulatory agency that oversees recalls, the Food and Drug Administration (FDA). The researchers obtained FDA recall data for drug and medical devices from 2003 to 2012 that included a mandatory, firm-provided defect awareness date along with a recall initiation date, which allows the FDA to measure the actual time to recall, making it harder for firms to delay a recall decision.

"The NHTSA does not require firms to provide defect awareness dates," Wowak said. "However, requiring auto firms to report the date that they first became aware of a defect may discourage them from hiding in the herd and prompt them to make more timely and transparent recall decisions, reducing the prevalence of clustering, which creates unnecessary delays in removing harmful products from the market."

Cancer cells are smart when it comes to anti-cancer drugs, evolving and becoming resistant to even the strongest chemotherapies over time. To combat this evasive behavior, researchers have developed a method named D2O-probed CANcer Susceptibility Test Ramanometry (D2O-CANST-R) to see, at single-cell/organelle level, how pharmaceuticals induce cancer cell death and how cancer cells adapt.

The research, conducted by the Qingdao Institute of Bioenergy and Bioprocess Technology (QIBEBT) of the Chinese Academy of Sciences (CAS), was published on Jan. 12 in Analytical Chemistry, a journal of the American Chemical Society.

"Understanding the mechanism of cellular response to drugs and pharmaceutical therapies is crucial to improving cancer treatment," said paper author XU Jian, director of the Single-Cell Center at QIBEBT. He explained that cancer cells can resist chemotherapy by changing metabolic activity for adaptation to drug stress, but exactly how this happens is poorly understood. "Approaches are needed to rapidly illuminate the particular effects of a drug on metabolic activity of cancer cells. This is clinically important as precise and personal administration of cancer chemotherapy is crucial for saving cancer patients' lives."

Maryam Hekmatara, a PhD student of XU, and her workmates paired a powerful algorithm with Raman spectroscopy, which involves using a laser to excite photons in a sample to reveal structural information, including interactions. They examined how rapamycin, an anti-cancer drug, changed the metabolic activity in a human cancer cell line and in yeast.

Their method revealed the changes small organelles inside the cells made in energy use and consumption. With a resolution capability of less than one micrometer - the width of a human hair is typically 80 to 100 micrometers, for comparison - the approach has the potential to reveal the metabolism in a cancer cell with very fine details.

"The method is able to rapidly and precisely track and distinguish changes in lipid and protein metabolic-inhibitory effect of rapamycin," Hekmatara said, noting the method takes just days compared to traditional tests that can take much longer to see if an individual patient's cells will respond favorably to a drug. "It is also very precise, as it can distinguish cancer cell responses to drugs at the single cell and single organelle resolution, which is crucial for understanding why the drug is - or is not - effective."

The researchers plan to further study how cells become resistant, as well as further develop their method as a personalized approach to determine the most effective anti-cancer drug for a patient.

Summary

Ultra-small nanomedicines of approximately 18 nm were fabricated by dynamic ion-pairing between Y-shaped block copolymers and nucleic acid drugs, such as siRNA and antisense drugs.

Chemically modified and double-stranded oligonucleotides dramatically enhanced the stability of the ultra-small nanomedicines in the blood circulation.

The ultra-small size allows for high permeability in cancer tissues by slipping through the cracks in tumor vasculatures and stromal tissues.

Clinical trials and preclinical studies using the developed ultra-small nanomedicines are proceeding for cancer therapy.

Published in the website of Journal of Controlled Release on January 6.

https://doi.org/10.1016/j.jconrel.2021.01.001

Main body

January 19, 2021 - Kawasaki in Japan: The Innovation Center of NanoMedicine (Director General: Prof. Kazunori Kataoka, Location: Kawasaki-City in Japan, Abbreviation: iCONM) recently developed an ultra-small nanomedicines called Unit Polyion Complex (uPIC)* in collaboration with a group led by Prof. Kanjiro Miyata in Department of Material Engineering, Graduate School of Engineering, The University of Tokyo. uPICs with a diameter of about 18 nm have an excellent permeability in cancer tissues, and thus, they are expected to selectively deliver small nucleic acid drugs to intractable cancers, such as brain tumors with very narrow capillaries and pancreatic cancer coated with tissue called fibrous stroma.

Nucleic acid drugs**, such as messenger RNA (mRNA), small interfering RNA (siRNA), and antisense oligonucleotides (ASO), have the advantage of being easier to manufacture and less costly than antibody drugs. However, they are rapidly decomposed by nucleases when they are injected into human. Recently, a variety of nanomedicines are developed to overcome this drawback. In particular, lipid-based nanomedicines are highlighted as mRNA vaccines that prevent new coronavirus infections, even though lipid component-mediated adverse events, such as anaphylactic shock, remain to be further investigated. For the nucleic acid delivery, we are focusing on the development of polymeric nanomedicines***, which are composed of non-biological components to avoid the risk of immunological responses.

uPICs are formed through an electrostatic interaction between "Y-shaped block copolymers (YBCs) comprising branched poly(ethylene glycol) and cationic polylysine" and "a single molecule of nucleic acid drugs". Since uPICs carry only one molecule of oligonucleotide, their size (~18 nm) can be adjusted to be dramatically smaller than that of existing nanomedicines using lipids (~100 nm). Another feature is that uPICs maintain a dynamic equilibrium with free YBCs,* allowing for the excellent stability of uPICs in the bloodstream. Due to these two features, ultra-small size and high stability, uPICs are able to deliver oligonucleotides to brain tumors equipped with the blood-brain tumor barrier. In the paper published in J. Control. Release on January 6, we focused on the structure of oligonucleotides in order to further enhance the stability of uPICs in the blood. As a result, we succeeded in significantly extending the blood half-lives of uPICs through two approaches: (1) using chemically modified nucleic acids and (2) changing oligonucleotides from single-strand to double-strand via hybridization. The obtained results show the great potential of nanomedicine for the oligonucleotide delivery. Clinical trials and preclinical research using uPICs have been already launched, and it is expected that excellent nanomedicines will be produced one after another in near future.

*uPIC (unit polyion complex) : Nanomedicines consisting of one molecule of oligonucleotide and one or two molecules of Y-shaped block copolymer(s), of which the size is approximately 18 nm and is in dynamic equilibrium with free Y-shaped block copolymers in human body. See the demonstration film => https://youtu.be/E90zF6_gL28

S. Watanabe, K. Hayashi, K. Toh, H. J. Kim, X. Liu, H. Chaya, S. Fukushima, K. Katsushima, Y. Kondo, S. Uchida, S. Ogura, T. Nomoto, H. Takemoto, H. Cabral, H. Kinoh, H. Y. Tanaka, M. R. Kano, Y. Matsumoto, H. Fukuhara, S. Uchida, M. Nangaku, K. Osada, N. Nishiyama, K. Miyata and K. Kataoka, "In vivo rendezvous of small nucleic acid drugs with charge-matched block catiomers to target cancers" Nature Communications 10, 1894 (2019) (https://www.nature.com/articles/s41467-019-09856-w)

**Nucleic acid drugs : A drug that treats a disease by acting on the gene (DNA) that causes a specific disease and the mRNA transcribed from it by controlling the transcription and expression of genetic information. Various drugs are studied and developed, such as antisense drugs that bind to nucleic acids that serve as genetic information and inhibit the transcription, and siRNA that cleaves mRNA and causes it to lose its function.

See http://www.nihs.go.jp/mtgt/section-1/related%20materials/0-19.pdf

***Polymeric nanomedicines : Micelles (nano-micelles) with a diameter of several tens of nm formed by associating amphipathic polymers with various functional molecules in water.

H. Cabral, K. Miyata, K. Osada, K. Kataoka, "Block copolymer micelles in nanomedicine applications" Chem. Rev.118 (14) 6844-6892 (2018) (DOI: 10.1021/acs.chemrev.8b00199)

Every year around 734 million tons of wheat straw are produced worldwide, a large amount of waste, which is cheap and has had no well-defined use until now. Recently, the RNM-271 Chemical Engineering and FQM-383 NANOVAL Organic Chemistry research groups at the University of Córdoba have been able to give a new use to this agricultural excess material, by using it as the foundation in order to manufacture polyurethane foams.

Also known as foam rubber, this plastic material, often manufactured from petroleum by-products, is extremely versatile within the industry and has multiple uses in the construction and automobile sectors as a sealant as well as a thermal and acoustic insulator.

The new paper, published on the cover of Polymers, and on which Chile's Advanced Polymers Research Center (CIPA) also participated, has found a new purpose for this wheat waste. After this waste is liquefied, polyols are obtained. These polyols are one of the key compounds that play a role in the chemical reaction that makes polyurethane foams.

To date, castor oil has been one of the main candidates in the race to obtain sustainable polyurethane foam that does not require petroleum. The issue, as explained by one of the main authors of the paper, Esther Rincón, is that this vegetable oil "does not offer complete hardness and dryness once exposed to air", one of the keys to proper rubber foam formation.

For this reason, the new research proposed substituting 50% of this castor oil for wheat straw, with results that offer up very similar characteristics to those generated by traditional manufacturing processes that use non-renewable compounds: "We were able to obtain very desirable parameters in the manufacturing of foam, converting 96% of the wheat used with an almost maximum performance", explains Esther Rincón. In addition, as pointed out by the researcher, they obtained higher levels of biodegradability than those reached by the products currently on the market, meaning that this material takes less time to decompose.

Use in plant nurseries

While these new polyurethane foams could have infinite applications and even be manufactured with other kinds of biomass, the research group, in the second stage of their study, will use them in plant nurseries to help with plant growth. "Instead of watering the plant, and with the aim of dealing with drought problems and preventing overwatering, we would inject the water into the foam so that the plant can consume it as needed", explains the researcher.

An international consortium of scientists, initiated by Reinhard Kienberger, Professor of Laser and X-ray Physics at the Technical University of Munich (TUM), several years ago, has made significant measurements in the femtosecond range at the U.S. Stanford Linear Accelerator Center (SLAC).

However, on these miniscule timescales, it is extremely difficult to synchronize the X-ray pulse that sparks a reaction in the sample on the one hand and the laser pulse which 'observes' it on the other. This problem is called timing jitter, and it is a major hurdle in ongoing efforts to perform time-resolved experiments at XFELs with ever-shorter resolution.

Now, a large international research team has developed a method to get around this problem at XFELs and demonstrated its efficacy by measuring a fundamental decay process in neon gas.

Good timing can avoid radiation damage

Many biological systems - and some non-biological ones - suffer damage when they are excited by an X-ray pulse from an XFEL. One of the causes of damage is the process known as Auger decay. The X-ray pulse ejects photoelectrons from the sample, leading to their replacement by electrons in outer shells. As these outer electrons relax, they release energy which can later induce the emission of another electron, known as an Auger electron.

Radiation damage is caused by both the intense X-rays and the continued emission of Auger electrons, which can rapidly degrade the sample. Timing this decay would help to evade radiation damage in experiments studying different molecules. In addition, Auger decay is a key parameter in studies of exotic, highly excited states of matter, which can only be investigated at XFELs.

Research team delivers pioneering and highly accurate approach

To chart Auger decay the scientists used a technique dubbed self-referenced attosecond streaking, which is based on mapping the electrons in thousands of images and deducing when they were emitted based on global trends in the data.

For the first application of their method, the team used neon gas, where the decay timings have been inferred in the past. After exposing both photoelectrons and Auger electrons to an external 'streaking' laser pulse, the researchers determined their final kinetic energy in each of tens of thousands of individual measurements.

"Crucially, in each measurement, the Auger electrons always interact with the streaking laser pulse slightly later than the photoelectrons displaced initially, because they are emitted later," says Prof. Reinhard Kienberger, who helped to develop the experiment's design. "This constant factor forms the foundation of the technique." By combining so many individual observations, the team was able to construct a detailed map of the physical process, and thereby determine the characteristic time delay between the photo- and Auger emission.

Streaking method leads to success

The required high time resolution is made possible by the so-called streaking method. "This technique is successfully applied in our laboratory. In several preliminary papers of our group, we have performed time-resolved measurements on free-electron lasers using the streaking method," says TUM PhD student Albert Schletter, co-author of the publication. "Using this method, we were able to measure the delay between X-ray ionization and Auger emission in neon gases with the highest precision," explains lead author Dan Haynes of Hamburg's Max Planck Institute for the Structure and Dynamics of Matter.

The researchers are hopeful that self-referenced streaking will have a broader impact in the field of ultrafast science. "Self-referenced streaking may facilitate a new class of experiments benefitting from the flexibility and extreme intensity of XFELs without compromising on time resolution," adds co-author Markus Wurzer, who is a PhD student of Prof. Kienberger.

INSECTS The spirea aphid, Aphis spiraecola, an invasive pest, has been discovered for the first time in Denmark by University of Copenhagen researchers. The extent of its current distribution remains unknown, but in time, it could prove to be a troublesome pest for Danish apple growers.

Aphis

Whether the discovery of this aphid in Denmark is an isolated incident, or if the species has made itself at home due to a milder climate, remains unknown to the researchers. Closer investigation is needed. Photo: UCPH/Uni.Budapest

In a collaboration with colleagues at the University of Budapest, University of Copenhagen researchers have analysed and compared a number of samples of green aphids from apples around the world and discovered a new apple-loving pest in Denmark.

The bright greenish yellow spirea aphid--Aphis spiraecola-- which most likely originates in East Asia, has gradually become a widespread pest in tropical and temperate regions around the planet. While it is especially problematic for citrus and apple trees, it can attack many other plant species. The aphid has been in the United States for the last 100 years and was discovered in Mediterranean countries in 1939. However, the spirea aphid has never been witnessed in the Nordic countries before.

"It is a serious pest that is more well known in countries a touch warmer than Denmark and is particularly harmful to citrus crops. It was identified in Germany in 2000, and the Baltic states a few years later. Now, it is here in Denmark. So, this is definitely something that we need to keep an eye on, as it could prove to be problematic for Danish apple growers," warns Associate Professor Lene Sigsgaard of the University of Copenhagen's Department of Plant and Environmental Sciences. For the past 20 years, Sigsgaard has researched natural predators and pest regulation in apple and other species.

Sucks nourishment out of the plants upon which it poos

Fact Box

Species: Aphis spiraecola Patch, also known as the spirea aphid or green citrus aphid (Hemiptera, Aphididae)

Physical appearance: Bright greenish yellow to apple green aphid easily confused with the green apple aphid (Aphis pomi), yet with minor morphological differences. The aphid often occurs in mixed colonies of other aphids.

Origin: Probably East Asia

Distribution: Now widespread over tropical and temperate regions worldwide. Can be spread with plant material. Winged generations during spring and late summer allow the species to spread themselves.

Host plants: Spirea, citrus, and apples are primary hosts where eggs are laid. The species also attacks other seed fruits, stone fruits, etc., and in the tropics, species including cocoa. The aphid can live on at least 20 different plant genera, making it very polyphagous.

Life: Across most of its range, the species reproduces asexually year-round (females give birth to new females without mating). In Denmark, the vast majority of aphid species winter as eggs, except for the peach aphid. Whether this new species will winter in Denmark as eggs or aphids in large numbers is unknown.

Impact: Commonly attacks citrus and apple trees. Aphids suck nourishment from plants. Sooty mold growing in honeydew can decrease a plant's ability to photosynthesize. The aphid causes apple leaves to curl and may cause the tips of branches to produce abnormally little growth. Severely-infested leaves become small, bright and may fall prematurely. Symptoms are similar to those caused by green apple aphids.

Viruses: The species is a virus vector for several species including CTV on citrus and plum pox virus.

Read the research article: https://static-curis.ku.dk/portal/files/253648977/108_2020_PPS.pdf

Aphids have specialised mouth parts designed to pierce and suck nourishment from plants. Their liquid excrement, honeydew, is characterized by sticky areas on leaves and fruit. Sooty mold spores are captured by and can grow in the sticky honeydew coating a leaf, causing affected leaves to become dark, which blocks sunlight and reduces photosynthesis.

"Aphids can affect a plant in several ways. Among other things, they suck nourishment from plants, energy that would have otherwise been used to produce new shoots and fruits. This stresses plants and can reduce yields in both the current and following season," explains Lene Sigsgaard.

While the rosy apple aphid is currently enemy number one in Danish apple orchards, the bright green spiraea aphid could cause problems too. Only the future can tell what this little sucker's ultimate impact will be.

Virus spreaders

Aphis spiraecola is a virus vector on citrus fruit and can also spread plum pox virus, also called Sharka, which has yet to be observed in Denmark.

Whether the discovery of this aphid in Denmark is an isolated incident, or if the species has made itself at home due to a milder climate, remains unknown to the researchers. Closer investigation is needed.

Its natural predators, which typically keep aphid populations in check and limit damage, could help to regulate this invasive new aphid.

With increased biodiversity in and around orchards and fields, readily catalyzed by planting flowering hedges and flower rows, populations of natural predators such as ladybirds, green lacewings, spiders, kissing bugs and parasitoid wasps can be supported to combat and reduce aphid populations.

Half of all young people treated for severe obesity have neuropsychiatric problems, according to a new study by researchers from Lund University and Gothenburg, Sweden, among others. Two thirds of the teens suffered from some type of mental health problem, as reported by themselves or their parents.

Both obesity and mental illness have increased among young people during the 2000s. Researchers have long observed a connection between obesity and ADHD/depression/eating disorders, but it has seldom been studied.

The present study involved 48 teenagers (73% girls), with an average age of 15 and an average BMI of 42, which is severe obesity. Half of the participants received medical treatment for obesity, while the other half underwent surgery.

The teenagers' parents completed questionnaires to measure their children's symptoms of ADHD and autism. The adolescents themselves responded to questions about binge eating and symptoms of depression.

The results show that over half of the parents estimated that their teenagers had difficulties resembling ADHD and/or autism, despite only a few of them having been previously diagnosed with these conditions.

"Symptoms of ADHD mean that the person has difficulty with impulse control. This increases the risk of eating without being hungry and the tendency to opt for quick solutions such as fast food", says Kajsa Järvholm, a psychology researcher at Lund University and the University of Gothenburg.

"People on the autism spectrum are sometimes more selective in their eating than others. They only accept certain dishes but may eat more of them as a result", she says.

One fifth of the adolescents reported suffering symptoms of depression. One third of them reported problems with binge eating, which is a loss of control resulting in the person eating large quantities of food in a short time.

"Contrary to our expectations, the adolescents with neuropsychiatric difficulties did not have more problems with binge eating and depression than the other adolescents in the group", says Järvholm.

Altogether, the information provided by the parents and adolescents revealed that two thirds of the patients in the study had difficulties arising from neuropsychiatric problems, binge eating and/or depression.

The researchers believe that the findings reveal a need to personalise treatments for adolescents with severe obesity as the majority also reported mental illness.

Researchers in the UK and the United States have succeeded in 'fine tuning' a new thermoplastic biomaterial to enable both the rate at which it degrades in the body and its mechanical properties to be controlled independently.

The material, a type of polyester, has been designed for use in soft tissue repair or flexible bioelectronics by a team at the University of Birmingham in the UK and Duke University in the US.

Materials that successfully replicate the necessary elasticity and strength of biological tissues but which also biodegrade over an appropriate timescale are extremely difficult to engineer. This is because the chemistry used to produce a material's mechanical properties will also typically govern the rate at which it degrades.

In a new advance, the team has now shown how the addition of succinic acid - a product found naturally within the body - can be used to control the degradation rate.

In a new study, published in Nature Communications, researchers showed how the polyester biomaterial degrades gradually over a period of four months, with healthy tissues growing into and eventually replacing the implant. Tests in rats were also carried out to confirm the material's biocompatibility and safety.

By varying the amounts of succinic acid the team could control the rate at which water penetrates the material and hence the degradation speed. Usually, the structural changes that increase degradation speed would cause a loss of strength, but this material has been designed with specific stereochemistry that mimics natural rubber and allow its mechanical properties to be finely controlled. This means any loss of strength can be compensated for by making suitable stereochemical adjustments. This is a significant advance that has so far not been achieved in any other degradable biomaterial.

Co-author of the study Professor Andrew Dove explains: "Biological tissues are complex with varying elastic properties. Efforts to produce synthetic replacements that have the right physical characteristics and that can also degrade in the body have been ongoing for decades.

"Part of the challenge is that a 'one-size-fits-all' approach doesn't work. Our research opens up the possibility of engineering biological implants with properties that can be fine-tuned for each specific application."

Professor Matthew Becker, who holds dual appointments in chemistry and mechanical engineering and materials science at Duke, notes that the biomaterials and regenerative medicine communities have been severely limited to a few materials which lack the diversity of properties reported in this study. "The materials we have developed offer a real advance in the ongoing search for new biomaterials. The tunable nature of the material makes it suitable for a range of different applications, from replacement bone to vascular stents to wearable electronics. Additional work to prove the biocompatibility of the material and its use in more advanced demonstration is ongoing."