China Science & Technology Forum

[JSCh]

Posted: Apr 18, 2018
Nanotechnology takes steps towards artificial retinas

(Nanowerk Spotlight) Sensory substitution with flexible electronics is one of the intriguing fields of research that takes place in nanotechnology labs around the world. Scientists already fabricate electronic devices that can replicate, to some degree, some of the human senses, such as touch (electronic skin – e-skin), smell (e-nose), and taste (e-tongue).

In line with this focus on human senses, in the future artificial retinas integrated with the human body may not only repair damaged vision but also expand it to see a wider range wavelengths (e.g. ultraviolet light).

The human retina is a film-shaped tissue behind the vitreous body in the eye. Photosensitive cells in the retina convert incoming light energy into bioelectric signals that are carried to the brain by the optic nerve.

Researchers in China now have demonstrated a new self-powered brain-linked vision electronic skin (e-skin) for mimicking the human retina.

"The general idea of our device design of brain-linked vision electronic skin is constructing an integrated flexible system including photodetector array, information analyzer, signal transmitter, and electricity power unit," Xinyu Xue, a professor at the College of Sciences at Northeastern University, Shenyang, tells Nanowerk. "While various research groups already have reported flexible photo detecting electronics, a battery-free, flexible and efficient power-supply unit remains an important bottleneck of the flexible vision e-skin. Another problem is to input the photo detecting signal into the brain for participating in the vision perception and relevant behavior intervention."

Optical images of the vision e-skin. (Reprinted with permission by Wiley-VCH Verlag)

Xue and collaborators from University of Electronic Science and Technology of China Chengdu and Shenzhen Institutes of Advanced Technology have published their findings in Advanced Functional Materials ("A Self-Powered Brain-Linked Vision Electronic-Skin Based on Triboelectric-Photodetecing Pixel-Addressable Matrix for Visual-Image Recognition and Behavior Intervention")

"Our self-powered vision e-skin is different from traditional complex integrated systems and combines the electricity-generating, photo-detecting, and neurobionics of signal transmission into one single chemical/physical process," explains Xue. "In this process, the photo detecting units in the e-skin harvest human-motion energy and output triboelectric signals containing the photo detecting information, acting as both the power source and the photo detecting signal for mimicking vision."

A novelty in this work is that the triboelectric and photo detecting effects are coupled in one single process.

The team's novel fabrication process employs, in successive order: standard photolithography; printed circuit board technique; PDMS soft-template method; electron beam evaporation process; and electrochemical polymerization. The resulting film device is a polypyrrole/polydimethysiloxane (Ppy/PDMS) triboelectric photo detecting pixel-addressable matrix.

"Our new fabrication technique can lower the production cost of traditional complex sensory-substitution systems and can be easily extended to various brain–machine interaction applications," Xue points out.

Fabrication process of the e-skin. (Reprinted with permission by Wiley-VCH Verlag)

To demonstrate the workings of their self-powered vision e-skin, the scientists attached it to the corner of a person's eye and . The motion of blinking eyes generated enough output power of the triboelectric generator to power the device and, in this test setting, detect UV illumination.

"The e-skin can map single-point and multi-point illumination stimuli (visual-image recognition) via the multichannel data acquisition method," says Xue. "In the next stages of our work, we will investigate self-powered multi-perception e-skin, including tactility, gustation, olfaction and audition. And we will also try to further investigate the brain-device interaction for practical purposes."

By Michael Berger – Michael is author of two books by the Royal Society of Chemistry: Nano-Society: Pushing the Boundaries of Technology and Nanotechnology: The Future is Tiny. Copyright © Nanowerk


Nanotechnology takes steps towards artificial retinas | Nanowerk Spotlight

 

[JSCh]

Characterizing ‘keyhole’ is first step to fighting obesity at the cellular level
Apr. 18, 2018, 1:11 PM

An international team has uncovered the potential to beat obesity at the cellular level, characterizing for the first time a complex, little-understood receptor type that, when activated, shuts off hunger.

Jens Meiler, professor of chemistry and pharmacology at Vanderbilt University, said pharmaceutical companies long have attempted to develop a small-molecule drug that could do just that. But until now, nobody knew exactly what the receptor looked like, making it nearly impossible to design the key to activating it.

​

Jens Meiler’s team determined the first crystal structure for a neuropeptide Y receptor, deciphering the thousands of carbon, oxygen, nitrogen and other atoms involved with it and how they bind to one another. (Brian Bender/Vanderbilt University)

Finding the “keyhole”
The team determined the first crystal structure for a neuropeptide Y receptor, deciphering the thousands of carbon, oxygen, nitrogen and other atoms involved with it and how they bind to one another. Meiler and a Ph.D. student in his laboratory, Brian J. Bender, translated the inherently low-quality data about the atoms’ coordinates to build accurate computer models of both the inactive receptor and what it looks like when activated.

“This is a very important milestone in the drug discovery process,” Meiler said. “The big contribution of this paper is to list the atoms with all the specific coordinates of where they are sitting in space and where they are bound to each other. We’ve actually found where there are little pockets in the structure where we can build a small molecule to bind.

“Before, it was like trying to design a key without knowing the shape of the keyhole.”

Their findings are published today in the journal Nature. Other authors include researchers from the Chinese Academy of Sciences in Shanghai and Leipzig University in Germany.

Next steps
The next step in this molecular-level research is target validation: proving that the receptor really does control hunger. Past studies revealed that when the receptor is blocked from functioning in mice, they become obese.

“Once you eat, you produce this peptide, it activates the receptor, and then you don’t feel hungry anymore and you stop eating,” Meiler said. “The idea here is that we could upregulate this receptor with a small molecule and create this feeling of not being hungry, so that you eat less.”

Meiler said the Nature paper is part of a much larger, ongoing study that already has produced starting points for the development of potential small-molecule therapeutics.

The breakthrough is possible through a long-standing international collaboration between Vanderbilt and Leipzig Universities with Bender spending months conducting experiments in Leipzig and several scientists from Leipzig traveling to Vanderbilt. The student exchange is supported by the Max Kade Foundation and the National Science Foundation (OISE 1157751). The research at Vanderbilt University is supported by the National Institute of Health (R01 DK097376, R01 GM080403), and the National Science Foundation (CHE 1305874).



Characterizing ‘keyhole’ is first step to fighting obesity at the cellular level | Vanderbilt News | Vanderbilt University

Zhenlin Yang, Shuo Han, Max Keller, Anette Kaiser, Brian J. Bender, Mathias Bosse, Kerstin Burkert, Lisa M. Kögler, David Wifling, Guenther Bernhardt, Nicole Plank, Timo Littmann, Peter Schmidt, Cuiying Yi, Beibei Li, Sheng Ye, Rongguang Zhang, Bo Xu, Dan Larhammar, Raymond C. Stevens, Daniel Huster, Jens Meiler, Qiang Zhao, Annette G. Beck-Sickinger, Armin Buschauer, Beili Wu. Structural basis of ligand binding modes at the neuropeptide Y Y1 receptor. Nature, 2018; DOI: 10.1038/s41586-018-0046-x​

 

[JSCh]

18 April 2018
Flexible TVs and high performance wearable smart tech one step closer

Flexible televisions, tablets and phones as well as ‘truly wearable’ smart tech are a step closer thanks to a nanoscale transistor created by researchers at The University of Manchester and Shandong University in China.

The international team has developed an ultrafast, nanoscale transistor – known as a thin film transistor, or TFT, - made out of an oxide semiconductor. The TFT is the first oxide-semiconductor based transistor that is capable of operating at a benchmark speed of 1 GHz. This could make the next generation electronic gadgets even faster, brighter and more flexible than ever before.

A TFT is a type of transistor usually used in a liquid crystal display (LCD). These can be found in most modern gadgets with LCD screens such as smart phones, tablets and high-definition televisions.

How do they work? LCD features a TFT behind each individual pixel and they act as individual switches that allow the pixels to change state rapidly, making them turn on and off much more quickly.

But most current TFTs are silicon-based which are opaque, rigid and expensive in comparison to the oxide semiconductor family of transistors which the team from the UK and China are developing. Whilst oxide TFTs will improve picture on LCD displays, it is their flexibility that is even more impressive.

Aimin Song, Professor of Nanoelectronics in the School of Electrical & Electronic Engineering, The University of Manchester, explains: “TVs can already be made extremely thin and bright. Our work may help make TV more mechanically flexible and even cheaper to produce.

“But, perhaps even more importantly, our GHz transistors may enable medium or even high performance flexible electronic circuits, such as truly wearable electronics.

"Wearable electronics requires flexibility and in many cases transparency, too. This would be the perfect application for our research. Plus, there is a trend in developing smart homes, smart hospitals and smart cities – in all of which oxide semiconductor TFTs will play a key role.”
Prof Aimin Song, Professor of Nanoelectronics

"Wearable electronics requires flexibility and in many cases transparency, too. This would be the perfect application for our research.

“Plus, there is a trend in developing smart homes, smart hospitals and smart cities – in all of which oxide semiconductor TFTs will play a key role.”

Oxide-based technology has seen rapid development when compared to its silicon counterpart which is increasingly close to some fundamental limitations. Prof Song says there has been fast progress in oxide-semiconductors in recent years and extensive efforts have been made in order to improve the speed of oxide-semiconductor-based TFTs.

So much so some oxide-based technology has already started replacing amorphous silicon in some gadgets. Prof Song thinks these latest developments have brought commercialisation much closer.

He added: “To commercialise oxide-based electronics there is still a range of research and development that has to be carried out on materials, lithography, device design, testing, and last but not the least, large-area manufacturing. It took many decades for silicon technology to get this far, and oxides are progressing at a much faster pace.

“Making a high performance device, like our GHz IGZO transistor, is challenging because not only do materials need to be optimised, a range of issues regarding device design, fabrication and tests also have to be investigated. In 2015, we were able to demonstrate the fastest flexible diodes using oxide semiconductors, reaching 6.3 GHz, and it is still the world record to date. So we’re confident in oxide-semiconductor based technologies.”


Flexible TVs and high performance wearable smart tech one step closer | University of Manchester

Yiming Wang, Jin Yang, Hanbin Wang, Jiawei Zhang, He Li, Gengchang Zhu, Yanpeng Shi, Yuxiang Li, Qingpu Wang, Qian Xin, Zhongchao Fan, Fuhua Yang, Aimin Song. Amorphous-InGaZnO Thin-Film Transistors Operating Beyond 1 GHz Achieved by Optimizing the Channel and Gate Dimensions. IEEE Transactions on Electron Devices, 2018; 1 DOI: 10.1109/TED.2018.2807621​

 

[JSCh]

Porous Salts for Fuel Cells: Organic salts with high proton conductivity
Thursday, April 19, 2018 8:52 am EDT

Scientists have developed a new class of crystalline porous organic salts with high proton conductivity for applications such as proton-exchange membranes for fuel cells. As reported in the journal Angewandte Chemie, polar channels that contain water play a critical role in proton conduction. At about 60 °C and high humidity, their proton conductivity is one of the best yet found in a porous material.

Porous organic materials are potentially useful for many applications, including catalytic systems, separation processes, and gas storage. Although these framework-like structures vary greatly, they have one thing in common: their components are connected through covalent bonds. Porous organic salts, on the other hand, are a new class of materials with components held together by ionic bonds, the attractive forces between positive and negatively charged ions. They are challenging to produce because their pores usually collapse; the ionic bonds of previously known organic salts are not strong enough to stabilize a porous structure.

Researchers working with Teng Ben at Jilin University (Changchun, China) have now successfully combined organic bases and acids to produce salts with very strong bonds and defined crystalline structures that form stable pore systems. These highly porous solids have the highest inner surface area ever found in an organic salt. The scientists demonstrated a significant correlation between the strength of the ionic bonds and the stability of the pore structure.

The pores in the salts form one-dimensional channels and can hold water. The water molecules are bound to each other and to the charged groups through hydrogen bonding. These aspects give the salts their unusually high proton conductivity. Materials with high proton conductivity have become the focus of attention because they are good electrolytes for fuel cells. In a fuel cell, two half reactions of a chemical reaction occur while physically separated. The most popular version uses the reaction oxygen and hydrogen to form water. In this case, the two cells must exchange protons (positively charged hydrogen atoms) through an electrolyte—usually through a proton-conducting polymer membrane. Scientists have been searching for more efficient, robust electrolytes. These new salts may be candidates. They are very stable at higher temperatures and their proton conductivity increases as the temperature rises.

In conventional polymer membranes, proton transport occurs through water-containing channels through which the protons within the network are transferred from one molecule to the next through hydrogen bonded water molecules. In the salts, the transport mechanism is different. Calculations indicate that the protons are sent through the channels by “courier”: A water molecule binds a proton and diffuses through the channel, releasing the proton on the other side.

Cite and link: Teng Ben et al., Angewandte Chemie International Edition, 10.1002/anie.201800423. doi.org/10.1002/anie.201800423



Porous Salts for Fuel Cells: Organic salts with high proton conductivity | Wiley News Room – Press Releases, News, Events & Media

 

[LKJ86]

2018.4.20

 

[JSCh]

Int'l team launches project to sequence DNA of all complex life on Earth
Source: Xinhua | 2018-04-24 07:10:33 | Editor: huaxia

The Earth BioGenome Project aims to sequence all eukaryotic species. This superkingdom of life includes all organisms except bacteria and archaea. (Xinhua/CREDIT: Graphic by Mirhee Lee)

WASHINGTON, April 23 (Xinhua) -- An international consortium of scientists is proposing the most ambitious project in the history of biology: sequencing the DNA of all known eukaryotic species on Earth.

The initiative, described on Monday in the Proceedings of the National Academy of Sciences, is led by a coordinating council with members from the United States, the European Union, China, Brazil, Canada, Australia and some African countries.

The benefits of the monumental project promise to be a complete transformation of the scientific understanding of life on Earth and a vital new resource for global innovations in medicine, agriculture, conservation, technology and genomics.

The central goal of the Earth BioGenome Project (EBP) is to understand the evolution and organization of life on our planet by sequencing and functionally annotating the genomes of 1.5 million known species of eukaryotes, a massive group that includes plants, animals, fungi and other organisms whose cells have a nucleus that houses their chromosomal DNA.

To date, the genomes of less than 0.2 percent of eukaryotic species or fewer than 15,000 species have been sequenced, according to 24 interdisciplinary authors.

The project also seeks to reveal some of the estimated 10 to 15 million unknown species of eukaryotes, most of which are single cell organisms, insects and small animals in oceans.

Researchers estimated the proposed initiative will take 10 years and cost approximately 4.7 billion U.S. dollars.

Scientists compared it to the hugely successful precedent of the Human Genome Project. It costed roughly 4.8 billion in today's dollars and generated an estimated return-on-investment ratio of 141-to-one.

"The Earth BioGenome Project will give us insight into the history and diversity of life and help us better understand how to conserve it," said Gene Robinson, director of the Carl R. Woese Institute for Genomic Biology at the University of Illinois who chairs the project.

Advances in technology have made the project feasible. The cost of whole genome sequencing has declined to about 1,000 dollars for a draft-quality sequence of human genome size and about 30,000 dollars for a reference-quality assembly of the chromosomes of an average eukaryotic genome.

With advances in high-performance computing, data storage and bioinformatics, the high throughput assembly and characterization of genomes is now feasible, according to the researchers.

The completed project is expected to require about one exabyte (one billion gigabytes) of digital storage capacity.

The working group also sees the project as being essential for developing new drugs for infectious and inherited diseases as well as creating new biological synthetic fuels, biomaterials, and food sources for growing human population.

The Earth BioGenome Project also plans to capitalize on the "citizen scientist" movement to collect specimens.

The project will likely enable the development of new technologies, such as portable genetic sequencers and instrumented drones that can go out, identify samples in the field, and bring those samples back to the laboratory.

 

[Adam WANG SHANGHAI MEGA]

China to commercialize 5G technology by second half of 2019
Source: Xinhua| 2018-04-23 22:33:09|Editor: yan



FUZHOU, April 23 (Xinhua) -- China will apply 5G technology to terminal devices as early as the second half of 2019, leading to the primary commercialization of the technology in the near future, according to an official with the Ministry of Industry and Information Technology (MIIT).

"China started 5G research experiments in 2016, and entered the third stage of system verification this year," Wen Ku, head of the MIIT information and communication department, said at the ongoing first Digital China Summit in Fuzhou, capital of east China's Fujian Province.

China has launched 5G cooperation mechanisms with Japan, the Republic of Korea, the European Union and the United States, with international companies joining the research and development, he said.

Wen said device manufacturers such as Huawei and Ericsson had participated in development of 5G products to help create a complete 5G industrial chain.

Given the significantly greater speed -- up to 10 gigabits per second -- that 5G offers, the next-generation ultra-fast networks will see ways of life change more than in the 4G era, in virtually everything from how we "interact" with our cars to how we use the products in our homes.

KEY WORDS:5G

 

[JSCh]

Chinese scientists sequence antimalarial plant genes, finding way to extract more medicine
Source: Xinhua| 2018-04-25 00:14:39|Editor: yan


WASHINGTON, April 24 (Xinhua) -- Chinese researchers reported on Tuesday in the journal Molecular Plant a high-quality draft genome sequence of Artemisia annua, a Chinese shrub producing a potent antimalarial compound Artemisinin and a way to extract more antimalarial medicine from the plant.

The findings can be used to metabolically engineer plant lines that produce higher levels of artemisinin as the low amount of artemisinin produced in the leaves of this sweet wormwood does not meet the global demand.

"Nearly half of the world's population is at risk of malaria," said senior study author Tang Kexuan with Shanghai Jiao Tong University. "Our strategy for the large-scale production of artemisinin will meet the increasing demand for this medicinal compound and help address this global health problem."

According to the World Health Organization, malaria affected approximately 216 million people in 91 countries in 2016 and caused an estimated 445,000 deaths worldwide that year alone.

The best available treatment for malaria is artemisinin-based combination therapy. In addition to its antimalarial activity, therapeutic effects of artemisinin have been reported for cancer, tuberculosis, and diabetes.

However, the supply of artemisinin is limited because this medicinal compound typically makes up only 0.1 percent to 1.0 percent of the dry weight of Artemisia annua leaves.

FINDING PROTEIN-CODING GENES

To fully harness this compound's therapeutic potential, researchers have developed metabolic engineering strategies aimed at enhancing the expression of artemisinin biosynthetic pathway genes.

These efforts failed to generate Artemisia annua lines that produced high levels of artemisinin, though, primarily because they focused on modifying gene expression only upstream or downstream of the artemisinin biosynthetic pathway.

A major hurdle for metabolic engineering strategies has been the lack of reference genome sequences and limited information about the genes involved in regulating artemisinin biosynthesis.

Tang and his collaborators generated a high-quality draft assembly of the 1.74 gigabase Artemisia annua genome, which contains 63,226 protein-coding genes, one of the largest numbers among sequenced plant species.

It took several years to complete the genome sequence due to its large size and high complexity.

The study added a wealth of information about Asteraceae, one of the largest families of plants consisting of more than 23,600 species of herbs, shrubs, and trees distributed throughout the world, including many with considerable medicinal, ornamental, and economic importance.

"A major impediment to the exploitation of the Asteraceae resources in basic and breeding sciences has been the absence of reference genome sequences; to date, only the sunflower and chrysanthemum genomes have been released," Tang said.

"The Artemisia annua genome and transcriptome data we provide here will be a valuable asset for fundamental biological research on plant evolution and other topics as well as applied breeding programs," Tang said.

EXTRACTING MORE MEDICINE

The Artemisia annua genome sequence provided new insights into the entire metabolic pathway involved in artemisinin biosynthesis. Analysis of the protein-coding genes and gene expression patterns revealed the regulatory networks underlying artemisinin biosynthesis.

Based on the genomic and transcriptomic data, the researchers identified novel genes involved in regulating artemisinin biosynthesis. By simultaneously increasing the activity of three genes, namely HMGR, FPS, and DBR2, spanning the entire artemisinin biosynthetic pathway, the researchers generated Artemisia annua lines that produced high artemisinin levels, 3.2 percent of the dry weight of the leaves.

Leveraging these findings, Tang and his team have sent artemisinin-rich seed samples to Madagascar, the African country that grows the most Artemisia annua, for a field trial.

"We hope our research can enhance the global supply of artemisinin and lower the price from the plant source," Tang said.

 

[JSCh]

Your behavior in Starbucks may reveal more about you than you think
By Dennis Normile
Apr. 25, 2018 , 2:15 PM

How you behave in Starbucks may reveal something about whether your ancestors grew wheat or rice. That’s the conclusion of a new study in China, which finds that people descended from wheat farmers—who largely rely on themselves—typically drink coffee alone, whereas descendants of rice growers—who must work with their community to build complex irrigation fields—tend to sip in groups. These differences persist, even if a person has moved to a city and their family hasn’t farmed or grown rice for generations.

"I find the study very persuasive," says Richard Nisbett, a sociologist at the University of Michigan in Ann Arbor who was not involved in the work. "It certainly is plausible that the differences between cultures are carried across generations even though the practices that gave rise to the culture are now rare.”

Psychologists generally agree that—by very rough measure—Western cultures allow individuality to thrive, whereas most Asian cultures emphasize group responsibility. One line of thinking traces these traits back to early farming practices. Wheat farmers—such as those living in China’s north—can grow their crop pretty much on their own. But it takes a village to build the irrigation systems that flood China’s southern rice paddies. And because rice farming takes about twice as much work per hectare as wheat, early rice farming communities gave rise to cooperative systems of labor. The argument goes on to say that millennia later, these differences in behavior persist.

Thomas Talhelm, a sociologist at the University of Chicago in Illinois, decided to test those theories in an unlikely place: Starbucks. The team observed nearly 9000 people in 256 coffee shops, including local operations and international chains such as Starbucks. They ran their experiment in six cities: Beijing and Shenyang, in China's northern wheat belt; and the southern cities of Shanghai, Nanjing, Guangzhou, and Hong Kong, all in the traditional rice-growing region. Sure enough, on weekdays, roughly 10% more people were drinking their lattes alone in the wheat region than in the rice region. On weekends, that difference dropped to about 5%. (The researchers don’t have an explanation, this is their observation.)

In a second experiment, Talhelm and his team got creative. Psychological studies have also found that when individualists run into a problem they are likely to try to change the situation, he says, whereas collectivists are more likely to adapt themselves to the circumstances. So in selected Starbucks shops, the team set up a chair trap. They would position two chairs so that their backs were separated by the width of the researcher's hips. Patrons walking through the store would have to either move the chairs or turn sideways to squeeze through them. Most of the 678 Starbucks patrons just squeezed on through. But whereas only 6% of the southerners moved the chairs, 16% of the northerners did. (Follow-up questions by the researchers found that about 90% of the people in the Starbucks shops were from the respective local rice or wheat cultural region.)

The fact that these differences appeared among mostly middle-class city people suggests that rice-wheat differences are still alive and well in modern China, the authors conclude today in Science Advances.

Nisbett thinks the study did its job. "The chair technique is clever," he says, adding that it’s far superior to observational research, survey-based research, and studies in the lab.

Zhou Xiaoyu, an economist at Friedrich-Alexander University in Erlangen, Germany, who is originally from Beijing, agrees. "I believe they have done a good job at demonstrating that rice versus wheat farming has profound effects on cultural norms."

Talhelm says his team is considering trying a similar study in India, where there is also a split between rice- and wheat-growing areas. Unlike the different regions in China, where there are north-south climatic differences, the differing regions in India are all in similar climatic zones. Climate is a variable that could influence culture, so taking that issue out of the equation could answer the question of whether colder climes induce individualism.

Talhelm notes that the results also raise questions about expectations that Chinese would become more individualistic as they modernized, grew wealthy, and congregated in cities. He notes the cities in the southern rice areas are wealthier, more crowded, and more developed than the northern cities of Beijing and Shenyang. Yet the northerners still appear to be more individualistic. "People’s farming legacies seem to be more important than [gross domestic product] in explaining their everyday behavior," he says.


Your behavior in Starbucks may reveal more about you than you think | Science | AAAS

After observing the behaviors of customers in cafes in several modern Chinese cities, researchers report that people from rice-growing regions showed interdependent behaviors, like sitting in groups or squeezing themselves through narrowly placed chairs, whereas people from wheat-growing regions more often displayed individualistic behaviors, sitting alone or actively moving chairs that blocked their way. CREDIT: Carla Schaffer / AAAS

 

[JSCh]

FOR IMMEDIATE RELEASE
ACS News Service Weekly PressPac: Wed Apr 25 11:29:59 EDT 2018
Rabies trick could help treat Parkinsons Disease
“Targeted Brain Delivery of Rabies Virus Glycoprotein 29-Modified Deferoxamine- Loaded Nanoparticles Reverses Functional Deficits in Parkinsonian Mice”
ACS Nano

The rabies virus wreaks havoc on the brain, triggering psychosis and death. To get where it needs to go, the virus must first trick the nervous system and cross the blood brain barrier — a process that makes it of interest in drug design. Now, scientists report in ACS Nano a way to exploit the rabies virus machinery to deliver a Parkinson's disease medication directly to the brain.

Parkinson's disease, the slow degeneration of the brain cells that control movement, affects about a million Americans, according to the Parkinson's Foundation, and has no cure. While the exact cause of Parkinson's disease is unknown, a common feature of the illness is the accumulation of iron in neurons, inflicting damage and cell death. Some doctors are now using a metal-grabbing compound called deferoxamine to sop up the excess iron in patients, but high doses are needed due to the drug's limited capacity to enter the brain, bringing on serious side effects. To lower the effective dose, Yan-Zhong Chang, Xin Lou, Guangjun Nie, and colleagues wanted to take advantage of a key part of the rabies virus to usher deferoxamine into the brain.

Glycoprotein 29 is a part of the rabies virus that binds to a brain cell receptor and crosses the blood brain barrier. The researchers attached glycoprotein 29 to a nanoparticle stuffed full of deferoxamine. Then, they injected the iron-grabbing nanoparticles into mouse models of Parkinson's disease. The iron levels in the mouse brains dropped, reducing the brain damage and reversing the disease symptoms, without noticeable side effects. Since all of the components in the therapeutic agent are already approved for use in the clinic, the researchers are looking toward human trials.

The authors acknowledge funding from National Natural Science Foundation of China, the National Distinguished Young Scientists program, the Innovation Research Group of the National Natural Science Foundation, the Key Research Project of Frontier Science of the Chinese Academy of Sciences, Queensland−Chinese Academy of Sciences Collaborative Science Fund and Beijing Municipal Science & Technology Commission.

Note: ACS does not conduct research, but publishes and publicizes peer-reviewed scientific studies.



Rabies trick could help treat Parkinsons Disease - American Chemical Society

 

[JSCh]

Scanning Electron Microscope image shows a few of the carefully designed shaped of the chalcogenide glass deposited on a clear substrate. The shapes, which the researchers call “meta-atoms,” determine how mid-infrared light is bent when passing through the material.
Courtesy of the researchers

Improving mid-infrared imaging and sensing
Artificial optical materials could allow cheaper, flatter, more efficient detectors for night vision and other uses.

David L. Chandler | MIT News Office
April 26, 2018

A new way of taking images in the mid-infrared part of the spectrum, developed by researchers at MIT and elsewhere, could enable a wide variety of applications, including thermal imaging, biomedical sensing, and free-space communication.

The mid-infrared (mid-IR) band of electromagnetic radiation is a particularly useful part of the spectrum; it can provide imaging in the dark, trace heat signatures, and provide sensitive detection of many biomolecular and chemical signals. But optical systems for this band of frequencies have been hard to make, and devices using them are highly specialized and expensive. Now, the researchers say they have found a highly efficient and mass-manufacturable approach to controlling and detecting these waves.

The findings are reported in the journal Nature Communications, in a paper by MIT researchers Tian Gu and Juejun Hu, University of Massachusetts at Lowell researcher Hualiang Zhang, and 13 others at MIT, the University of Electronic Science and Technology of China, and the East China Normal University.

The new approach uses a flat, artificial material composed of nanostructured optical elements, instead of the usual thick, curved-glass lenses used in conventional optics. These elements provide on-demand electromagnetic responses and are made using techniques similar to those used for computer chips. “This kind of metasurface can be made using standard microfabrication techniques,” Gu says. “The manufacturing is scalable.”

He adds that “there have been remarkable demonstrations of metasurface optics in visible light and near-infrared, but in the mid-infrared it’s moving slowly.” As they began this research, he says, the question was, since they could make these devices extremely thin, “Could we also make them efficient and low-cost?” That’s what the team members say they have now achieved.

The new device uses an array of precisely shaped thin-film optical elements called “meta-atoms” made of chalcogenide alloy, which has a high refractive index that can form high-performance, ultrathin structures called meta-atoms. These meta-atoms, with shapes resembling block letters like I or H, are deposited and patterned on an IR-transparent substrate of fluoride. The tiny shapes have thicknesses that are a fraction of the wavelengths of the light being observed, and collectively they can perform like a lens. They provide nearly arbitrary wavefront manipulation that’s not possible with natural materials at larger scales, but they have a tiny fraction of the thickness, and thus only a tiny amount of material is needed. “It’s fundamentally different from conventional optics,” he says.

The process “allows us to use very simple fabrication techniques,” Gu explains, by thermally evaporating the material onto the substrate. They have demonstrated the technique on 6-inch wafers with high throughput, a standard in microfabrication, and “we’re looking at even larger-scale manufacturing.”

The devices transmit 80 percent of the mid-IR light with optical efficiencies up to 75 percent, representing significant improvement over existing mid-IR metaoptics, Gu says. They can also be made far lighter and thinner than conventional IR optics. Using the same method, by varying the pattern of the array the researchers can arbitrarily produce different types of optical devices, including a simple beam deflector, a cylindrical or spherical lens, and complex aspheric lenses. The lenses have been demonstated to focus mid-IR light with the maximum theoretically possible sharpness, known as the diffraction limit.

These techniques allow the creation of metaoptical devices, which can manipulate light in more complex ways than what can be achieved using conventional bulk transparent materials, Gu says. The devices can also control polarization and other properties.

Mid-IR light is important in many fields. It contains the characteristic spectral bands of most types of molecules, and penetrates the atmosphere effectively, so it is key to detecting a wide range of substances such as in environmental monitoring, as well as for military and industrial applications, the researchers say. Since most ordinary optical materials used in the visible or near-infrared bands are totally opaque to these wavelengths, mid-IR sensors have been complex and expensive to make. So the new approach could open up entirely new potential applications, including in consumer sensing or imaging products, Gu says.

The research was funded by the Defense Advanced Research Projects Agency (DARPA), under the Extreme Optics and Imaging Program, and the National Natural Science Foundation of China.



Improving mid-infrared imaging and sensing | MIT News

Li Zhang, Jun Ding, Hanyu Zheng, Sensong An, Hongtao Lin, Bowen Zheng, Qingyang Du, Gufan Yin, Jerome Michon, Yifei Zhang, Zhuoran Fang, Mikhail Y. Shalaginov, Longjiang Deng, Tian Gu, Hualiang Zhang, Juejun Hu. Ultra-thin high-efficiency mid-infrared transmissive Huygens meta-optics. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-03831-7​

 

[JSCh]

Unlocking rice gene diversity for food security
25 April 2018

A new study published in the Nature journal opens the possibility to accelerate rice breeding to achieve food security for some of the world’s most vulnerable rice farmers.

The groundbreaking research on Genomic variation in 3,010 diverse accessions of Asian cultivated rice maps the largest set of genomic variants for a crop species.

“This information leads to faster and more accurate development of varieties suited to various agricultural environments, especially for unfavorable rice-growing areas where the poorest and most vulnerable farmers reside. Plant breeders can make more intelligent choices in selecting traits for improved varieties that farmers can cultivate, which leads to food and nutrition security, “ says Dr. Jacqueline Hughes, International Rice Research Institute Deputy Director General for Research. “This is how advancements in rice science can impact the lives of millions of farmers and consumers,” she added.

A collaboration among IRRI, the Institute of Crop Sciences of the Chinese Academy of Agricultural Sciences (CAAS), BGI-Shenzhen, and 13 other partner institutions, the research will enable scientists to discover new gene variants and characterize known genes for important traits, such as the natural ability of a particular variety to resist diseases and withstand floods, drought, and salty water. Additionally, molecular breeders could use the genetic markers to select rice plants that are more likely to carry a desired trait before they are planted in the field.

“What could previously take up to 40 years from trait discovery to varietal development can now only take just a few years,” says Dr. Ruaraidh Sackville Hamilton, IRRI principal scientist and head of the International Rice Genebank at IRRI.

“In addition, we are also able to make the breeding process more efficient and precise, being more responsive in delivering varieties with traits that can adapt to the increasingly complex production environment, reduce environmental impact, produce higher yield with less resources, and the changing needs and demands of consumers,” Dr. Hamilton added.

This recent research revealed that, among the 3,000 rice genomes, there are significant variations in gene content and immense sequence variation. Researchers identified more than 10,000 new rice genes and over 29 million simple variations throughout the genome. Additionally, within the two major rice variety groups, the analysis revealed the existence of previously unreported populations that are unique to specific geographic origins. Other evidence revealed that Asian rice was domesticated multiple times thousands of years ago.

According to Dr. Kenneth McNally, IRRI senior scientist, this is the largest set of genomic variants discovered for a crop species that is freely and publicly available for plant breeders and scientists across the world. It already serves as material for training a new generation of plant biologists.

Dr. Zhikang Li, a collaborating scientist from CAAS, reported that the research results have ushered in a “new era of genome- and information-based breeding.” He added that it has been a vital and extensive resource for CAAS scientists as they work on large-scale trait discovery and allelic mining, identifying parents for breeding programs, and establishing a comprehensive genome-based trait database for future rice improvement.

According to Dr. Hei Leung, IRRI principal scientist and geneticist, there is still considerable work to be done to discover and understand other rice genomic variations in the collection of the International Rice Genebank at IRRI and other collections around the world.

“Next, we will explore the largely untapped diversity in wild rice species. This will greatly aid in defining genotype-phenotype relationships as well as improving our understanding of plant biology. To achieve this goal, we must continue the spirit of providing access to new information to the global community.” said Dr. Hei Leung.


IRRI - Unlocking rice gene diversity for food security

 

[cirr]

突破新纪录！清华大学首次实现25个独立接口间的量子纠缠

2018-04-27 20:43:33字号：A- A A+来源：科技日报

关键字:量子纠缠 量子计算机

科技日报4月27日消息，记者27日从清华大学获悉，该校交叉信息研究院段路明研究组在量子信息领域取得重要进展，首次实现25个量子接口之间的量子纠缠。相比于之前加州理工学院研究组保持的4个量子接口之间纠缠的世界纪录，段路明团队将纠缠的量子接口数目提高了约6倍。该成果相关论文近日发表在《科学·进展》上。

量子接口用于实现量子信息在光子和存储粒子（通常为原子）之间的相互转化，是连接量子存储器或量子计算单元与光量子通信通道间的重要界面。段路明介绍道，对量子网络而言，量子接口相当于现有的网络接口，量子接口越多，意味着更多的量子设备可以接入量子网络。“量子信息领域的最终目标是要实现量子互联网，而量子接口是量子互联网的基本元器件之一，能相互纠缠的接口越多越好。”

他进一步阐述道，在量子信息科学中，光子拥有最快的传输速度，是传播量子信息的最佳载体，而原子拥有很长的量子相干时间，被广泛应用于量子信息的存储。量子接口将光子和存储原子链接起来，实现量子信息在不同在载体间的高效相互转换。

量子接口虽然重要，但增加其纠缠数量难度巨大。2010年，著名量子信息和量子光学专家Kimble研究组实现4个量子接口之间的纠缠，此后多年在纠缠接口的数量上无重大进展。

“我们研发了新颖的二维量子接口阵列，解决了相关技术问题，可以方便地实现多个量子接口间的纠缠。”段路明说。研究人员通过光束复分技术，独立寻址并相干调控5 *5的量子接口阵列，制备了多体量子纠缠态，在25个量子接口之间，实验利用纠缠判据以高信度证明至少存在22体以上的真实纠缠，刷新了量子接口纠缠数量的世界纪录。审稿人对这一工作评价为，”这是一个创纪录的纠缠个数，也是构建第一个量子网络过程中的一个重要里程碑。“

段路明表示，接下来将致力于继续增加纠缠接口数量，同时进一步提高接口之间的纠缠质量。

该论文第一作者为清华大学交叉信息研究院博士研究生濮云飞，通讯作者为段路明，其他作者包括该学院博士研究生蒋楠、常炜、李畅、张胜及美国密西根大学博士研究生吴宇恺。该项目得到教育部、科技部以及清华大学的经费支持。

@Bussard Ramjet

 

[JSCh]

HKU claims to have developed new drug to prevent and treat HIV
2018-04-29 09:59 GMT+8

A team from Hong Kong University (HKU) claimed on Thursday that they have invented an antibody drug that can effectively prevent human immunodeficiency virus (HIV) infections and eliminate infected cells in mice.

After eight years’ research, the team, led by Professor Chen Zhiwei, director of HKU’s Aids Institute, found that by injecting the drug, which is an engineered tandem bispecific broadly neutralizing antibody's named ‘BiIA-SG’, to humanized mice, HIV particles can be blocked from entering target cells, making it impossible to be infected with the virus, according to a press release by HKU.

Currently, patients who are infected with HIV need to take a combination of three anti-retroviral drugs every day to suppress the virus, otherwise the “level of the virus would rebound”, Chen said at a press conference.

But in the research, when the drug is injected into a group of infected mice, it was found that the viral load dropped significantly to “an almost undetectable level” for at least four weeks before 58 percent of the mice exhibited signs of a viral rebound, which leads to a promising efficacy of eliminating HIV-I infected cells in humanized mice - rodents which carry human genes, tissues and cells.

Graphic abstract of the drug BiIA-SG. / Photo via Journal of Clinical Investigation

The research team’s goal, Chen said, was to lengthen the period of protection offered by its new antibody drug.

However, the team has so far only tested the drug on mice, but is now looking to experiment on larger animals such as monkeys, before conducting clinical trials on humans.

The findings of the study have been published in the Journal of Clinical Investigation, a peer-reviewed biomedical research journal published by the American Society for Clinical Investigation.

(Cover photo to courtesy: Hong Kong University)

 

[TaiShang]

Construction begins on advanced photon science facility
Xinhua, April 28, 2018

Construction started Friday in Shanghai on a facility designed to capture the real-time movement of particles.

The hard X-ray free electron laser facility, created with a total investment of nearly 9.5 billion yuan (1.5 billion U.S. dollars), is located in a national scientific center in Zhangjiang in Shanghai.

"It is like a high-speed, super clear camera. It can 'film' molecules, atoms, and electrons," said Zhu Zhiyuan, general manager of the project with Shanghai Tech University. "It can capture their real-time movements and play them back slowly, enabling scientists to figure out details of complex chemical reactions."

It is 3,110-meters long, including 2,795 meters of underground tunnel.

Traditional facilities of photon science can only take still photographs of particles.

"The facility is expected to offer unprecedented scientific opportunities, including solving the mystery of life and designing new medicines," said Zhao Zhentang, chief scientist of the project.