China Science & Technology Forum

[JSCh]

Plant scientists plan massive effort to sequence 10,000 genomes
By Dennis Normile Jul. 27, 2017 , 8:00 AM

SHENZEN, CHINA—Hopes of sequencing the DNA of every living thing on Earth are taking a step forward with the announcement of plans to sequence at least 10,000 genomes representing every major clade of plants and eukaryotic microbes. Chinese sequencing giant BGI and the China National GeneBank (CNGB) held a workshop yesterday on the sidelines of the International Botanical Congress, being held this week in BGI's hometown of Shenzhen, to discuss what they are calling the 10KP plan. About 250 plant scientists participated in the discussions and "are raring to go," says Gane Ka-Shu Wong, a genomicist and bioinformaticist at University of Alberta in Edmonton, Canada.

The 10KP plan will be a key part of the Earth BioGenome Project (EBP), an ambitious and still evolving scheme to get at least rough sequence data on the 1.5 million eukaryotic species, starting with detailed sequences of one member of each of the 9000 eukaryotic families. The effort to sequence plants is moving ahead a bit faster than other aspects of EBP "because plant scientists are more collaborative," Wong says jokingly.

The 10KP plan is also building on a previous 1000 plant (1KP) transcriptome project. That effort, launched in 2012 and now nearing completion, was also led by BGI, where Wong is an associate director.

"One thing we focused on (for 1KP) was sampling phylogenetic diversity, not just crops and model organisms," Wong says. That strategy will continue with 10KP. The transcriptome project has resulted in more than 50 papers, with the overall summary publication still to come. A lot of the analysis has focused on plant evolution. One surprise was that important transcription factors previously thought to have evolved as land plants colonized terrestrial habitats can actually be traced back to green algae, says Michael Melkonian, a botanist at the University of Cologne in Germany. Screening green algae also turned up new light-sensitive proteins that neuroscientists now use to study how different neurons interact and better understand neurological functioning.

Whereas the 1KP project only tackled the transcriptome, or all the messenger RNA expressed by an organism, 10KP will produce completely new sequences of the entire genome. And scientists expect an even larger bonanza of fundamental insights and economic spin-offs. The 10KP project "is 1KP on steroids," says Douglas Soltis, a plant biologist at the Florida Museum of Natural History at the University of Florida in Gainesville. He adds that one "wonderful thing" about the project is that it will provide reference genomes for "the numerous plant researchers studying nonmodel systems," he says. The project will also present "an unprecedented opportunity to address fundamental questions about plant evolution," says Stephen Smith, an evolutionary biologist at the University of Michigan in Ann Arbor. Study targets are expected to include the role of genome duplication, the correlation between genomic and morphological changes, and how rates of evolution changed over time.

One challenge Smith points to is the need to develop new means of analyzing and synthesizing sequencing information. "Existing tools and methods are unable to handle the extraordinary scale of the data," he says. Wong says another bottleneck will be dealing with the paperwork needed to comply with legal requirements of shipping plant material across borders, as well as complying with the Nagoya Protocol, an international pact that seeks to ensure the fair and equitable sharing of genetic resources. On the other hand, gathering specimens is easier than for other areas of genetics. "You don't have to chase down some animal, you can usually just go to a botanical garden," Wong says.

Xu Xun, who leads technical development for BGI, says the company and CNBG will cover the sequencing costs but "scientists will have to find their own funding for collecting samples and for analysis." As for timing, Wong says they hope to gather the samples in the next 2 years and "we hope to wrap up the sequencing and analysis in 5 years."

"We're ready to start sequencing yesterday," Wong says. And plant scientists are eager. After the meeting yesterday in Shenzhen, "several people came up already wanting to send samples," he says.


Plant scientists plan massive effort to sequence 10,000 genomes | Science | AAAS

 

[JSCh]

Effects of a major drug target regulated through molecular 'codes'
July 27, 2017

Rhodopsinarrestin. Credit: Parker de Waal, Xu Laboratory, Van Andel Research Institute

A team spearheaded by Van Andel Research Institute scientists has answered a long-standing question that may lead to more effective drugs with fewer side effects for diseases ranging from heart failure to cancer.

The findings, published today in Cell, reveal for the first time components of a G protein-coupled receptor (GPCR) named rhodopsin bound to a signaling molecule called arrestin, both crucial pieces of the body's intricate cellular communication network. The new discovery further refines a landmark 2015 Nature article that first described the structure of the two molecules in complex together.

--> https://phys.org/news/2017-07-effects-major-drug-molecular-codes.html

X. Edward Zhou, Yuanzheng He, Parker W. de Waal, Xiang Gao, Yanyong Kang, Ned Van Eps, Yanting Yin, Kuntal Pal, Devrishi Goswami, Thomas A. White, Anton Barty, Naomi R. Latorraca, Henry N. Chapman, Wayne L. Hubbell, Ron O. Dror, Raymond C. Stevens, Vadim Cherezov, Vsevolod V. Gurevich, Patrick R. Griffin, Oliver P. Ernst, Karsten Melcher, H. Eric Xu. Identification of Phosphorylation Codes for Arrestin Recruitment by G Protein-Coupled Receptors. Cell, 2017; 170 (3): 457 DOI: 10.1016/j.cell.2017.07.002

 

[Bussard Ramjet]

Effects of a major drug target regulated through molecular 'codes'
July 27, 2017

Rhodopsinarrestin. Credit: Parker de Waal, Xu Laboratory, Van Andel Research Institute

A team spearheaded by Van Andel Research Institute scientists has answered a long-standing question that may lead to more effective drugs with fewer side effects for diseases ranging from heart failure to cancer.

The findings, published today in Cell, reveal for the first time components of a G protein-coupled receptor (GPCR) named rhodopsin bound to a signaling molecule called arrestin, both crucial pieces of the body's intricate cellular communication network. The new discovery further refines a landmark 2015 Nature article that first described the structure of the two molecules in complex together.

--> https://phys.org/news/2017-07-effects-major-drug-molecular-codes.html

X. Edward Zhou, Yuanzheng He, Parker W. de Waal, Xiang Gao, Yanyong Kang, Ned Van Eps, Yanting Yin, Kuntal Pal, Devrishi Goswami, Thomas A. White, Anton Barty, Naomi R. Latorraca, Henry N. Chapman, Wayne L. Hubbell, Ron O. Dror, Raymond C. Stevens, Vadim Cherezov, Vsevolod V. Gurevich, Patrick R. Griffin, Oliver P. Ernst, Karsten Melcher, H. Eric Xu. Identification of Phosphorylation Codes for Arrestin Recruitment by G Protein-Coupled Receptors. Cell, 2017; 170 (3): 457 DOI: 10.1016/j.cell.2017.07.002

View attachment 414440​

Shouldn't really be in this section.

More than 90% authors are Americans.

 

[JSCh]

IBP Scientists Reveal Molecular Mechanism for RNA-Guided RNA Cleavage by Cas13a
Jul 28, 2017

Almost all archaea and half of bacteria possess Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and CRISPR-associated genes (Cas) adaptive immune systems, which protect microbes from the foreign nucleic acids. Cas13a is a newly identified effector of Class 2 and type VI CRISPR-Cas system. Cas13a was found to be a single-component programmable RNA-guided RNA-targeting CRISPR effector, protecting the host from the RNA viruses. Upon recognition of its RNA target, activated Cas13a engages in "collateral" cleavage of any free RNA in solution. However, the molecular mechanism of RNA-guided RNA cleavage is unknown.

In the study published online in Cell, research team led by Prof. WANG Yanli and Prof. ZHANG Xinzheng at the institute of Biophysics of the Chinese Academy of Sciences solved the 3.08 Å crystal structure of Leptotrichia buccalis (Lbu) Cas13a bound to crRNA and its target RNA, as well as the 3.2 Å cryo-EM structure of the LbuCas13a-crRNA complex.

These structural studies revealed that LbuCas13a adopts a bilobed architecture consisting of an α-helical REC lobe and a NUC lobe. The crRNA and target RNA form duplex RNA, located in a positively-charged central channel of the NUC lobe.

Interestingly, Cas13a protein and crRNA undergo significant conformational change upon target RNA binding. Researchers found that the guild-target RNA duplex formation triggers the conserved catalytic residues in HEPN1 domain to move towards the HEPN2 domain, activating the HEPN catalytic site of Cas13a. The activated Cas13a cleaves any single-stranded RNA in solution in a sequence non-specific manner.

Therefore, LIU's studies revealed a unique molecular mechanism by which Cas13a protein cleaves both single-stranded target RNA and collateral RNAs, resulting in cell death in bacteria. This altruistic cell suicide mediated by Cas13a is likely essential for evolution bacteria evolution.

Together with their earlier studies, they revealed that Cas13a has two separate catalytic sites for its two interdependent RNase activities. The HEPN1 domain and HEPN2 domain are responsible for RNA cleavage. The Helical-1 and HEPN2 domains may be also involved in pre-crRNA stabilization and processing. The HEPN2 domain appears to catalyze pre-crNA processing in Lbu, while the Helical-1 domain is critical for pre-crRNA processing in Leptotrichia shahii (Lsh).

These structural studies provide critical insights into the molecular mechanism of target RNA recognition and activation of Cas13a, which will significantly facilitate the research on this type VI CRISPR-Cas system and pave the way towards better development and utilizing of the RNA editing tool.

The research was funded by Natural Science Foundation of China, the Chinese Ministry of Science and Technology, and the Strategic Priority Research program of the Chinese Academy of Sciences, the National Thousand (Young) Talents Program from the Office of Global Experts Recruitment in China.

The X-ray diffraction data were collected at beamlines BL-17U and BL-19U at the Shanghai Synchrotron Radiation Facility. The cryo-EM data were collected at the Center for Biological Imaging.

The Crystal Structure of LbuCas13a-crRNA-target RNA Ternary Complex (Image by IBP)


IBP Scientists Reveal Molecular Mechanism for RNA-Guided RNA Cleavage by Cas13a---Chinese Academy of Sciences

 

[JSCh]

28 July 2017
Smart glasses let you turn off the lights in the blink of an eye

Lights please
Elisabeth Schmitt/Getty

By Lakshmi Supriya

Blink and the lights go out. A sensor on a pair of glasses that can pick up the motion of your skin when you blink could be used to switch the lights on and off, or to help those with limited or no mobility write messages on a computer.

“The good thing about the technology is the high sensitivity, which may become particularly useful in places where the motion is very limited,” says Ambarish Ghosh at the Indian Institute of Science, who wasn’t involved in the research.

Blink to scroll
The sensor, called a triboelectric generator, is thin enough to fit on the arms of a pair of glasses. It is made from multiple polymer layers with a coating of metal that acts as an electrode. Each time someone blinks, the motion of skin to the side of the eye causes the polymer layers to touch and release, generating an electrical signal. One, two or three consecutive blinks can be used to scroll through the alphabet to spell out a message on a computer, for example.

This signal can be transmitted through a wire or wirelessly, leading to the potential hands-free operation of various appliances, including cellphones. It could also aid people who have limited or no mobility of limbs because of accidents or conditions such as Lou Gehrig’s disease.

The glasses were created by Zhong Lin Wang at the Georgia Institute of Technology and his colleagues at the Chinese Academy of Sciences in Beijing. They first demonstrated the principle of harvesting energy using the triboelectric effect in 2013.

However, blinking is involuntary, and unless you enjoy a disco effect, it may turn appliances off and on when you don’t want them to. “You can set a threshold for the switch,” says Wang. Only when the signal is higher than the threshold, which means you really have to blink hard, can the switch be triggered.

This could be useful in many different applications, says Ghosh, such as using the motion of other muscles or in systems that may require constant monitoring, both biological and non-biological.

The team now plans to use the sensor on other parts of the body to explore its potential in intelligent robotics applications. Wang says that if they can improve the level of the signal generated, the entire system can be self-powered.


Smart glasses let you turn off the lights in the blink of an eye | New Scientist

Xianjie Pu, Hengyu Guo, Jie Chen, Xue Wang, Yi Xi, Chenguo Hu and Zhong Lin Wang. Eye motion triggered self-powered mechnosensational communication system using triboelectric nanogenerator. Science Advances 2017: DOI: 10.1126/sciadv.1700694

 

[JSCh]

Posted: Jul 29, 2017
Amplification on a chip: Research raises hope for erbium-based integrated photonics device

(Nanowerk News) ASU researcher Cun-Zheng Ning has made another breakthrough using the rare-earth metal erbium as the gain material for an optical amplifier, this time with an achievement that will enable its use for the first time with small chip optical technologies. The discovery attains a decades-long goal in the field of photonic integration, in which different small optical components are tightly combined for better performance and ease of fabrication.

Details of the new optical amplification were published in the July online edition of Nature Photonics ("Giant optical gain in a single-crystal erbium chloride silicate nanowire").

Ning, an electrical engineer, and Hao Sun from China’s Tsinghua University and their teams have succeeded in raising erbium's optical gain from the typical low level of a few dB to over 100 dB per centimeter of propagation. The significant increase in optical gain will make it possible for erbium-based materials to be integrated on a chip for optical amplifiers and lasers.

Read more: Amplification on a chip: Research raises hope for erbium-based integrated photonics device

#####​

Posted: Jul 29, 2017
Single molecular layer and thin silicon beam enable nanolaser operation at room temperature

(Nanowerk News) For the first time, researchers have built a nanolaser that uses only a single molecular layer, placed on a thin silicon beam, which operates at room temperature. The new device, developed by a team of researchers from Arizona State University and Tsinghua University, Beijing, China, could potentially be used to send information between different points on a single computer chip. The lasers also may be useful for other sensing applications in a compact, integrated format.

“This is the first demonstration of room-temperature operation of a nanolaser made of the single-layer material,” said Cun-Zheng Ning, an ASU electrical engineering professor who led the research team. Details of the new laser are published in the July online edition of Nature Nanotechnology ("Room-temperature continuous-wave lasing from monolayer molybdenum ditelluride integrated with a silicon nanobeam cavity").

Read more: Single molecular layer and thin silicon beam enable nanolaser operation at room temperature

 

[JSCh]

Optical lens can transfer digital information without loss
July 28, 2017 by Lisa Zyga

​

This optical field pattern resulting from the Talbot effect and the self-focusing property can be used to encode thirty-six bits of digital data. Credit: Wang et al. ©2017 American Physical Society

(Phys.org)—Researchers have designed an optical lens that exhibits two properties that so far have not been demonstrated together: self-focusing and an optical effect called the Talbot effect that creates repeating patterns of light. The researchers showed that the combination of these two properties can be used to transfer an encoded digital signal without information loss, which has potential applications for realizing highly efficient optical communication systems.

The scientists, Xiangyang Wang and Hui Liu at Nanjing University, Huanyang Chen at Xiamen University, along with their coauthors, have published a paper on the new lens, called a "conformal lens," in a recent issue of Physical Review Letters.

This type of a conformal lens, which is also known as a Mikaelian lens, arose from the field of transformation optics, which is based on the idea that lenses can direct light in analogy with how the curved geometry of spacetime bends light in general relativity.

The main goal of the study was to design a conformal lens that works simultaneously in two different regimes: the geometry optics regime, in which light is treated as a particle, and the wave optics regime, which also accounts for the wave-like properties of light.

Working in both regimes is challenging because the two regimes have two seemingly opposing requirements for the size of the working wavelengths. On one hand, the working wavelengths must be much smaller than the size of the lens, but at the same time they must be larger than the basic units that make up the lens.

To address this challenge, the researchers started with a Maxwell's fish-eye lens, which dates back to the 1850s, as the basis for the conformal lens. They explained that trying to realize a lens with the desired properties using conventional transformation optics is very challenging, in part due its demands on a three-dimensional medium. On the other hand, conformal transformation optics places demands on a two-dimensional medium, which eases the fabrication requirements.

"Although transformation optics can be used to design many novel optical devices, it is usually very difficult to use in practical systems, especially in the visible regime," Liu told Phys.org. "In our work, we have established a feasible experiment platform to obtain conformation transformation optical devices."

After constructing the conformal lens, the researchers demonstrated that the lens exhibits both self-focusing, which is a property of geometric optics, and the Talbot effect, which is a property of wave optics. In this way, the device connects the two distinct realms of geometry optics and wave optics.

Most interesting for potential applications is that the conformal Talbot effect displayed here is very different from the ordinary Talbot effect in other media due to the additional self-focusing property. One of the biggest differences is that, unlike the ordinary Talbot effect which experiences boundary diffraction, the conformal Talbot effect does not.

As a result of its lack of diffraction, the conformal Talbot effect can be used to transfer encoded optical patterns over long distances with a very small amount of distortion. The researchers expect that this ability could lead to a highly efficient method of transferring digital information in future high-speed optical communication systems with no information loss.

"We can send a stream of optical digits '0' and '1' by parallel communication, which is much faster than the serial communication used in regular optical waveguides or optical fibers," Liu said. "The conformal Talbot effect can help reduce transmission errors because of its non-diffractive properties and good self-focusing of the field patterns."

In the future, the researchers plan to explore various potential applications of conformal transformation optics, such as designing novel integrated photonic chips that can transport and process information in micro-optical circuits. These "conformal photonic chips" may one day be used in future quantum computers.

"We hope conformal transformation optics can be used in quantum simulators and quantum computers in the future," Chen said. "We also plan to mimic the quantum effects in the curved space of general relativity using conformal transformation optics, such as the horizon of a black hole and Hawking radiation."

More information: Xiangyang Wang et al. "Self-Focusing and the Talbot Effect in Conformal Transformation Optics." Physical Review Letters. DOI: 10.1103/PhysRevLett.119.033902

Abstract
Transformation optics has been used to propose various novel optical devices. With the help of metamaterials, several intriguing designs, such as invisibility cloaks, have been implemented. However, as the basic units should be much smaller than the working wavelengths to achieve the effective material parameters, and the sizes of devices should be much larger than the wavelengths of illumination to work within the light-ray approximation, it is a big challenge to implement an experimental system that works simultaneously for both geometric optics and wave optics. In this Letter, by using a gradient-index microstructured optical waveguide, we realize a device of conformal transformation optics (CTO) and demonstrate its self-focusing property for geometry optics and the Talbot effect for wave optics. In addition, the Talbot effect in such a system has a potential application to transfer digital information without diffraction. Our findings demonstrate the photon controlling ability of CTO in a feasible experiment system.
​

https://phys.org/news/2017-07-optical-lens-digital-loss.html

 

[JSCh]

China releases world's fastest and most accurate DNA sequencer
By Xu Xiaotong
2017-08-01 13:21 GMT+8

Chinese-made third generation DNA sequencer GenoCare was released on Monday in the city of Shenzhen in south China's Guangdong Province.

With full automation, the machine, developed by a research team from the Southern University of Science and Technology, can sequence samples of human genomes in less than 30 minutes with an accuracy up to 99.7 percent, making it one of the fastest and most precise DNA sequencers in the world.

The sequencer is the first of its kind that can be applied to clinical practice.

Prof. He Jiankui, leader of the research team, said the sequencer is expected to lower the cost of DNA sequencing of any person from the current 1,000 US dollars to 100 US dollars, enabling everyone to enjoy benefits brought by accurate treatment from DNA sequencing.

The core technology of GenoCare is single-molecule fluorescence sequencing. The machine detects single-molecule fluorescence by employing total internal reflection microscopy, together with sequencing-by-synthesis chemistry.

 

[Bussard Ramjet]

China releases world's fastest and most accurate DNA sequencer
By Xu Xiaotong
2017-08-01 13:21 GMT+8

Chinese-made third generation DNA sequencer GenoCare was released on Monday in the city of Shenzhen in south China's Guangdong Province.

With full automation, the machine, developed by a research team from the Southern University of Science and Technology, can sequence samples of human genomes in less than 30 minutes with an accuracy up to 99.7 percent, making it one of the fastest and most precise DNA sequencers in the world.

The sequencer is the first of its kind that can be applied to clinical practice.

Prof. He Jiankui, leader of the research team, said the sequencer is expected to lower the cost of DNA sequencing of any person from the current 1,000 US dollars to 100 US dollars, enabling everyone to enjoy benefits brought by accurate treatment from DNA sequencing.

The core technology of GenoCare is single-molecule fluorescence sequencing. The machine detects single-molecule fluorescence by employing total internal reflection microscopy, together with sequencing-by-synthesis chemistry.

The headline is misleading.

In the video it says, "one of the fastest and most precise."

Anyways, I have very limited knowledge about DNA sequencing technology, so I will wait and watch and let market determine the value of the machine.

 

[JSCh]

Growing Nearly Perfect Graphene At Scale
Using copper foils as a substrate for carbon deposition, scientists in Korea and China have devised an inexpensive technique to grow large graphene sheets

AsianScientist (Aug. 2, 2017) - A team of scientists from Korea and China have developed a method to synthesize large sheets of monolayer single-crystal graphene. They report their findings in the journal Science Bulletin.

Boasting high conductivity, strength and flexibility, graphene was proposed as one of the most likely substitutes for silicon and other materials. Polycrystalline graphene is formed by randomly oriented graphene islands, which decrease its quality. On the other hand, a honeycomb-shaped monolayer of carbon atoms, uniform throughout the whole material, offers exceptional properties to single-crystal graphene.

Currently, scientists can grow meter-sized polycrystalline graphene and smaller single-crystal graphene, ranging from 0.01 mm2 to a few square centimeters. The synthesis of large single-crystal graphene at a low cost has been considered a critical goal of graphene synthesis.

In this study, a team of researchers led by Professor Ding Feng and Professor Rodney Ruoff at the Center for Multidimensional Carbon Materials within the Institute for Basic Science reported the synthesis of a large sheet of monolayer single-crystal graphene.

The researchers grew graphene on the surface of a 5 × 50 cm2 copper foil, which was transformed into a single-crystal copper foil by heating to approximately 1,030 degrees Celcius. A temperature slope from hot to cold moved the so-called grain boundary onward, creating a perfect single crystal. During the heating and cooling treatment, copper atoms migrated inside the material, arranging into an ordered structure with fewer defects.

Then, using another technique called chemical vapor deposition, millions of parallel graphene islands were formed on the copper foil surface. As more carbon atoms deposit on the foil, the islands kept on growing until they coalesced and formed a very-close-to-perfect single-crystal graphene layer that covered the entire available surface.

“The secret to obtaining single-crystal graphene of a very large size is to have a perfect single crystal copper as a base to start with. Large single-crystal copper foils are not available in the market, so labs must build it with their own means,” explained Ding.

The team’s findings allow a leap forward in graphene production, advancing from a technique that synthesizes a few square centimeters of single-crystal graphene in a couple of hours, to an optimized method that allows the creation of an almost-perfect (> 99.9 percent aligned) 5 × 50 cm2 single-crystal graphene in just 20 minutes.

Moreover, the low production costs, comparable to commercially available lower quality polycrystalline graphene films, could expand its usability. The method is expected to stimulate further fundamental work on graphene and related materials, including large scale folding of graphene sheets, similar to paper, creating origami-like or kirigami-like shapes, which could be applied to future flexible circuits.

“The dream of many scientists is to make graphene the material of the future, to replace silicon,” Ding said. “We are exploring the best material on which to grow graphene and using copper as a substrate for other interesting 2D materials.”



Growing Nearly Perfect Graphene At Scale | Asian Scientist Magazine | Science, Technology and Medicine News Updates From Asia

Xiaozhi Xu, Zhihong Zhang, Jichen Dong, Ding Yi, Jingjing Niu, Muhong Wu, Li Lin, Rongkang Yin, Mingqiang Li, Jingyuan Zhou, Shaoxin Wang, Junliang Sun, Xiaojie Duan, Peng Gao, Ying Jiang, Xiaosong Wu, Hailin Peng, Rodney S. Ruoff, Zhongfan Liu, Dapeng Yu, Enge Wang, Feng Ding, Kaihui Liu. Ultrafast epitaxial growth of metre-sized single-crystal graphene on industrial Cu foil. Science Bulletin, 2017; DOI: 10.1016/j.scib.2017.07.005

Abstract
A foundation of the modern technology that uses single-crystal silicon has been the growth of high-quality single-crystal Si ingots with diameters up to 12 inches or larger. For many applications of graphene, large-area high-quality (ideally of single-crystal) material will be enabling. Since the first growth on copper foil a decade ago, inch-sized single-crystal graphene has been achieved. We present here the growth, in 20 min, of a graphene film of (5 × 50) cm2 dimension with >99% ultra-highly oriented grains. This growth was achieved by: (1) synthesis of metre-sized single-crystal Cu(1 1 1) foil as substrate; (2) epitaxial growth of graphene islands on the Cu(1 1 1) surface; (3) seamless merging of such graphene islands into a graphene film with high single crystallinity and (4) the ultrafast growth of graphene film. These achievements were realized by a temperature-gradient-driven annealing technique to produce single-crystal Cu(1 1 1) from industrial polycrystalline Cu foil and the marvellous effects of a continuous oxygen supply from an adjacent oxide. The as-synthesized graphene film, with very few misoriented grains (if any), has a mobility up to ∼23,000 cm2 V−1 s−1 at 4 K and room temperature sheet resistance of ∼230 Ω/□. It is very likely that this approach can be scaled up to achieve exceptionally large and high-quality graphene films with single crystallinity, and thus realize various industrial-level applications at a low cost.​

 

[rendong]

China's Leading Silicon Photonics Platform Developed by IMECAS
Recently, the Integrated Circuit Advanced Process Center of Institute of Microelectronics of Chinese Academy of Sciences (IMECAS) released silicon photonics platform based on 8-inch Complementary Metal Oxide Semiconductor (CMOS) process line, which marks a significant increase in R & D capability in the field of silicon photonics in China.

Silicon photonics technology is a new technology developed under the trend of integration of microelectronics and optoelectronics in the post Moore Era. It utilizes mature CMOS technology and platform, and develops optoelectronic devices and chips based on silicon-based materials.

Silicon photonics not only has the urgent application demand in the field of optical communication and optical interconnection, but also is the potential technology to realize the optical interconnection and optical computer in the future. For a long time, China lacks perfect silicon photonic technology platform, which restricts the development of silicon photonics technology to a great extent.

Since 2015, IMECAS has begun to develop silicon photonics process technology based on the 8-inch CMOS process line. The Institute has developed a complete set of silicon photonic process modules. A series of silicon photonic devices including single-mode waveguide, Y branch, optical cross device, coupled grating, tunable attenuator, germanium detector and modulator have been successfully demonstrated.

The Process Design Kit (PDK) based on the platform has been released. The Institute is providing the service of Multi Project Wafer (MPW) process for domestic customers.

This silicon photonics platform is the first platform which provides a complete process of silicon photonic chip in China.

 

[JSCh]

Study Reveals How to Reprogram Cells in our Immune System
The discovery could improve treatments for autoimmune diseases and cancer
Gladstone Press Release / August 2, 2017

SAN FRANCISCO, CA—When the immune system is imbalanced, either due to overly active cells or cells that suppress its function, it causes a wide range of diseases, from psoriasis to cancer. By manipulating the function of certain immune cells, called T cells, researchers could help restore the system’s balance and create new treatments to target these diseases.

Scientists at the Gladstone Institutes revealed, for the first time, a method to reprogram specific T cells. More precisely, they discovered how to turn pro-inflammatory cells that boost the immune system into anti-inflammatory cells that suppress it, and vice versa.

The researchers studied two types of cells called effector T cells, which activate the immune system to defend our body against different pathogens, and regulatory T cells, which help control the immune system and prevent it from attacking healthy parts of its environment.

“Our findings could have a significant impact on the treatment of autoimmune diseases, as well as on stem cell and immuno-oncology therapies,” said Gladstone Senior Investigator Sheng Ding, PhD, who is also a professor of pharmaceutical chemistry at the University of California, San Francisco.

By drawing on their expertise in drug discovery, Ding’s team identified a small-molecule drug that can successfully reprogram effector T cells into regulatory T cells. Their study, published in the renowned journal Nature, describes in detail a metabolic mechanism that helps convert one cell type into another.

This new approach to reprogram T cells could have several medical applications. For instance, in autoimmune disease, effector T cells are overly activated and cause damage to body. Converting these cells into regulatory T cells could help reduce the hyperactivity and return balance to the immune system, thus treating the root of the disease.

In addition, the study could improve therapies using stem cells. At least in theory, producing regulatory T cells could promote immune tolerance and prevent the body from rejecting newly-transplanted cells.

“Our work could also contribute to ongoing efforts in immuno-oncology and the treatment of cancer,” explained Tao Xu, postdoctoral scholar in Ding’s laboratory and first author of the study. “This type of therapy doesn’t target the cancer directly, but rather works on activating the immune system so it can recognize cancer cells and attack them.”

Many cancers take control of regulatory T cells to suppress the immune system, creating an environment where tumors can grow without being detected. In such cases, the team’s findings could be used to transform regulatory T cells into effector T cells to strengthen the immune system so it can better recognize and destroy cancer cells.

The research was supported by the Gladstone Institutes.

Other authors of this study include Katerina Akassoglou, Kai Liu, Min Xie, Jae Kyu Ryu, Ke Li, Tianhua Ma, Haixia Wang, Saiyong Zhu, Nan Cao, and Yu Zhang from Gladstone; Edward M. Driggers, Kelly M. Stewart, and Dongwei Zhu from Agios Pharmaceuticals; and Chen Dong, Xiaohu Wang, and Lu Ni from Tsinghua University in China.
https://gladstone.org/about-us/press-releases/study-reveals-how-reprogram-cells-our-immune-system


Study Reveals How to Reprogram Cells in our Immune System | Gladstone Institutes

Tao Xu, Kelly M. Stewart, Xiaohu Wang, Kai Liu, Min Xie, Jae Kyu Ryu, Ke Li, Tianhua Ma, Haixia Wang, Lu Ni, Saiyong Zhu, Nan Cao, Dongwei Zhu, Yu Zhang, Katerina Akassoglou, Chen Dong, Edward M. Driggers, Sheng Ding. Metabolic control of TH17 and induced Treg cell balance by an epigenetic mechanism. Nature, 2017; DOI: 10.1038/nature23475

 

[JSCh]

Lightweight Catalyst for Artificial Photosynthesis: Carbonitride aerogels mediate the photocatalytic conversion of water
Nanochemistry meets macrostructures: Chinese scientists report the synthesis of a macroscopic aerogel from carbonitride nanomaterials which is an excellent catalyst for the water-splitting reaction under visible-light irradiation. The study published in the journal Angewandte Chemie adds new opportunities to the material properties of melamine-derived carbonitrides.

Friday, August 4, 2017 7:05 am EDT

Melamine can be polymerized with formaldehyde to give a highly durable and light resin, but it can also condensed to form nanostructures of carbonitride materials. These assemblies made of carbon and nitrogen combine the honeycomb-like electronically active network of graphene with some extra functionality of nitrogen. Searching for ways to assemble these nanostructures into a stable macroscopic architecture, Xinchen Wang and his team at Fuzhou University in China have now prepared a catalytically highly active and stable lightweight material, which serves well in artificial photosynthesis and offers very interesting structural and electronic properties.

Aerogels are gels but without water—up to ninety-nine percent of their structure is air. This porosity gives them a huge surface ideal for catalytic or sensory application. As carbonitrides are materials with very interesting nanostructure and graphene-like properties but nitrogen functionality, it has long be sought to bring them into a controlled macroscopic assembly. "Since CN is rich in nitrogen-containing groups, it is expected that CN may have interesting assembly behaviors like proteins or peptides in biological systems," the authors said.

The enhanced surface area and higher number of catalytic sites would make these aerogels highly functional macroscopic materials. Employing only physical interparticle forces intrinsic to the nanoparticles, the scientists prepared the aerogel by making a colloidal aqueous solution of carbonitride nanoparticles to settle first into a hydrogel, then converting it into a stable aerogel by a conventional freeze-drying technology. "This method has several advantages, including scalability for mass production and low cost," the authors said. In combination with a platinum co-catalyst, the aerogel was much better a photocatalyst for hydrogen evolution than the bulk carbonitride, and hydrogen peroxide was generated from pure water under visible-light irradiation when the bulk carbonitride failed.

Thus, by joining forces of chemical and physical characteristics from the nano- to the macroscale, they have created a new lightweight material with excellent catalytic prospects. This promising application of melamine building blocks points the way forward to new materials, and is far apart from the well-established mass production of the light and durable, but not so thermostable melamine plastic dishes.

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Cite and link: Xinchen Wang et al., Angewandte Chemie International Edition, 10.1002/anie.201705926. doi.org/10.1002/anie.201705926



Lightweight Catalyst for Artificial Photosynthesis: Carbonitride aerogels mediate the photocatalytic conversion of water | Wiley News Room – Press Releases, News, Events & Media

 

[JSCh]

Light, strong alloy may alter design of aircraft
By WANG HONGYI | China Daily | Updated: 2017-08-07 03:57

A new kind of nano material developed by domestic researchers is expected to become the next-generation aviation material and boost the development of the country's homegrown large passenger aircraft.

The nano ceramic aluminum alloy was developed by the research team from the School of Materials Science and Engineering at Shanghai Jiao Tong University.

Light in weight, such new material has the characteristics of high rigidity, high strength, fatigue resistance, low expansion and high temperature resistance.

Instead of the traditional physical method of mixing the ceramic and aluminum alloy, researchers put the nano ceramic particles into aluminum alloy through an innovative chemical process. During the process, the size, shape, and distribution of the particles were controlled.

This helped improve the rigidity and strength of the new material. At the same time, the processing and manufacturing performance of aluminum alloy remains, said Professor Wang Haowei, who led the project.

"The nano ceramic aluminum alloy material helps break the bottleneck of large-scale application in engineering," Wang said.

The university's scientists started the basic research in the field in the early 1990s, Wang said, and they have made a lot of experiments in developing the new material over the years.

"Compared with titanium alloy and high-temperature alloy, the performance of aluminum alloy with 3D printing technology is much lower. The 3D printing components made of nano ceramic aluminum alloy can achieve the performance of forgings," Wang said.

So far, the new material has already been used in the Tiangong-1 and Tiangong-2 space labs, quantum satellites and meteorological satellites. It also has been used in key components of automotive internal-combustion engines, which not only reduces weight efficiency, but also saves energy, reduces emissions and improves safety.

Wang said researchers are stepping up their cooperation with Commercial Aircraft Corp of China to promote the use of such new materials in large aircraft.

"The advances in aviation development are closely connected to the progress of materials, and we are closely watching the development and performance of the new material," said Wu Guanghui, vice-president of COMAC, the general designer of C919, the first homegrown large passenger aircraft

Wu said the nano ceramic aluminum alloy material is still being tested, and is expected to be used in the C919 aircraft, replacing some of current components, which were imported.

A new material innovation center was established at the university last week, which aims to further boost the industrialization of the nano ceramic aluminum alloy material. Based on Wang's research team, the center was jointly established by the Huaibei government of Anhui province, Shanghai Jiao Tong University, Shanghai JuneYao Group and Anhui Xiangbang Composite Material Co.

In 2013, the Huaibei government established a midterm test and manufacturing base with an annual production capacity of more than 1,000 metric tons, and it also founded the Anhui Xiangbang Composite Material Co. The production of such material aims to meet large-scale applications in aerospace, aviation and auto industries.

 

[JSCh]

XIEG Drone Team Completes First Geological Monitoring in Sarez Lake
Aug 08, 2017

A UAV (unmanned aerial vehicle) team with the Xinjiang Institute of Ecology and Geography (XIEG) of the Chinese Academy of Sciences recently finished their first aerial photography mission at the Sarez Lake of Tajikistan on its geological monitoring of Usoy.

This is the first time for the team to complete aerial monitoring of geological status in the Sarez Lake area which locates deep in the inaccessible Pamir Mountains and is therefore hard for obtaining high-precision geological data due to its high altitude and bad traffic condition.

The five-member team operates their UAV for a day-and-half aerial photography mission as high as 5,000 meters above the Sarez Lake, and obtained a large quantity of geological data for further hazard monitoring.

Sarez Lake was formed in 1911 after an earthquake measuring 7.7 on the Richter scale. The earthquake caused a landslide of 2.2 km3, which formed the five kilometers long, 3.2 kilometers wide Usoy Dam. It is the tallest dam in the World, with a height about 600 meters.

The lake’s stability has been an internationally concerned question, considering local seismic activity and the fact that Sarez is located in one of the most earthquake-prone regions in the World. According to scientists, Usoy would be unsteady if an earthquake occurred in the future. Potential flooding poses a threat not only on the population of Tajikistan, but also inhabitants of Afghanistan, Uzbekistan and Turkmenistan.

The team captured more than 3,600 photos of the dam area about 70 km2 during the flights in one and a half days. Among them, over 1,500 photos are orthographic shooting with a 20-centimeter resolution and about 2100 oblique shooting with resolution of 10 centimeters.

This is the first time for Chinese scientists to carry out on-spot monitoring on Sarez Lake area, and has set a record for the XIEG drone team’s field operation.

The mission is one of many tasks of a cooperated project by XIEG and the Institute of Geology, Seismological Construction and Seismology of the Academy of Sciences of the Republic of Tajikistan. The project aims to provide scientific support for disaster warning of flood and landslide in Usoy dam through high-precision monitoring with UAV and high-resolution satellite.