China Science & Technology Forum

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Hungry? A Newly Discovered Neural Circuit May Be to Blame
NEUROSCIENCE NEWS JULY 5, 2018
Summary: Researchers have identified a subset of neurons in a region of the hypothalamus that play a critical role in regulating feeding and appetite in mice.

Source: AAAS.

A particular subset of neurons located in an enigmatic region of the hypothalamus plays a central role in regulating feeding and body weight in mice, a new study reveals. The results illuminate a previously unknown neural mechanism of feeding regulation and offer new perspectives on understanding changes in appetite.

Knowledge of the function of a region of the hypothalamus called the nucleus tuberalis lateralis, or NTL, is scarce, though scientists seek to better understand it as damage to this brain region in patients results in marked declines in appetite, and in rapid loss in body weight.

To further explore any role the NTL may have in regulation of feeding and body weight, Sarah Xinwei Luo and colleagues observed the behavior of somatostatin (SST) neurons in the NTL using a mouse model.

The authors found that the SST neurons were activated by both hunger (following overnight food deprivation) and after administration of the hunger hormone, ghrelin. Selective activation and deactivation of the neurons, using both drugs and optogenetics, demonstrated that eating behavior could be controlled – activation increased eating behavior, while inhibition significantly reduced it.

Total elimination of the neurons altogether resulted in decreased daily food intake as well as gradual weight gain.

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According to the study’s findings, SST neurons are required for controlling healthy eating and body weight. NeuroscienceNews.com image is in the public domain.

According to the study’s findings, SST neurons are required for controlling healthy eating and body weight.

In a related Perspective, Sabrina Diano notes that Luo et al.’s results are highly relevant – efforts to affect body weight and other physiological impairments associated with aberrant feeding behaviors, like obesity or anorexia nervosa, have been futile.

Despite the translational uncertainty between the neural circuitry of mice and humans, Luo et al.’s results are novel and warrant further investigation, says Diano.

Original Research: Abstract for “Regulation of feeding by somatostatin neurons in the tuberal nucleus” by Sarah Xinwei Luo, Ju Huang, Qin Li, Hasan Mohammad, Chun-Yao Lee, Kumar Krishna, Alison Maun-Yeng Kok, Yu Lin Tan, Joy Yi Lim, Hongyu Li, Ling Yun Yeow, Jingjing Sun, Miao He, Joanes Grandjean, Sreedharan Sajikumar, Weiping Han, and Yu Fu in Science. Published July 5 2018.
doi:10.1126/science.aar4983



Hungry? A Newly Discovered Neural Circuit May Be to Blame - Neuroscience News

 

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Evaluations aim to help innovation
By Zhang Zhihao | China Daily | Updated: 2018-07-06 09:54

New ways of measuring performance of top talent, projects offer many benefits

To promote innovation, China has launched its most detailed performance evaluation systems so far for talented researchers, institutes and projects, officials said on Thursday. The system will be more streamlined and efficient, they said.

The systems are part of recent reforms to cut bureaucracy in the auditing, evaluation and managerial process of scientific research and projects, according to new guidelines, which were issued recently by the general offices of the Communist Party of China Central Committee and the State Council.

"The new evaluation systems are the most comprehensive and detailed mechanisms to date," said He Defang, director of the department of policy, regulation and supervision of the Ministry of Science and Technology.

"These types of institutional reforms are typically proposed by departments, but this time it is straight from the top, which proves that State leaders are paying more attention to science-related government affairs."

Earlier evaluation reforms began nearly two decades ago, but they lacked clear, enforceable guidelines, which led to issues ranging from cumbersome paperwork to conflicts of interest, He said. The situation began to improve in 2013 as more government departments began experimenting with policies to reduce bureaucratic workload.

At the same time, most science evaluations tend to focus on individual projects, but China lacked both general and mid- to long-range evaluations about the role of research institutions and the social benefits of their output, he said.

Zhang Xu, deputy director of the ministry's department of innovation and development, said the new evaluation systems aim to optimize management, unleash the potential of scientists, clarify roles and research directions for research institutes and increase their capability to better serve national needs.

The new systems will also integrate different types of evaluations across various levels, including self-evaluations and institutional, departmental and third-party evaluations, leading to more balanced and objective results, Zhang said.

Each research institute will create a charter that acts as a set of basic governing principles and the basis for evaluations, Zhang said. The main items of the charter include research targets, responsible fields and national duty.

The results of an evaluation will have more weight in policy formation, project planning, talent recruitment and other major decisions related to the functions of the institute, Zhang said, adding that the legal entity for the institutes will be granted more power to make such decisions.

More practical criteria - such as socioeconomic benefits - will be added into a scientists' evaluations' for promotions, He said.

Legacy criteria, such as awards and the number of published papers, will serve only as references and not deciding factors, as in past evaluations.

"After all, it is unfair to hold back a capable surgeon's promotion because he spent all his time doing surgery and not writing papers," He said.

As for institutes, success will be measured by their end products and social impact, not just department size or budget, He said. Users of the technology will have greater say in the evaluation.

Xie Xin, deputy director of the ministry's department of resource allocation and management, said the reform will also strengthen the credibility of evaluations and the reviewers, with a zero-tolerance stance on fraud.

 

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Chinese Researchers Develop Meter-scale Single-wall Carbon Nanotube Thin Films

Meter-scale single-wall carbon nanotube (SWCNT) thin films with an excellent optoelectrical performance has been developed for the first time by Chinese researchers from Institute of Metal Research, Chinese academy of sciences.

SWCNTs have been considered one of the most promising candidates for flexible and transparent electronic devices due to their extraordinary mechanical, electrical, and optical properties. The production of high-quality SWCNT thin films by an efficient and scalable method has become a key issue for their practical application in electronics. However, two major obstacles remain for the research and development of macro-electronics based on SWCNT thin films. First, the size of fabricated SWCNT films is usually limited to the square centimeter scale, and the batch processing used is not scalable. Second, the optoelectrical performance of SWCNT films remains unsatisfactory due to the introduction of impurities and structural defects during the fabrication processes. Therefore, the production of high-quality SWCNT thin films by an efficient and scalable process remains a big challenge.

Recently, the researchers from Institute of Metal Research, Chinese academy of Sciences (IMR, CAS), proposed a continuous synthesis, deposition, and transfer technique for the fabrication of high-quality SWCNT thin films of meter-scale dimension with excellent optoelectrical performance. Large-area, flexible, and transparent all-CNT thin-film transistors (TFTs) and various integrated circuits (ICs) were also fabricated to demonstrate the potential use of these SWCNT thin films in large-area, flexible, and transparent electronics. These results have been published on 28 June, 2018 in Advanced Materials (doi: 10.1002/adma.201802057).

SWCNTs are continuously synthesized by a floating catalyst chemical vapor deposition technique, and then deposited on a moving membrane filter forming SWCNT thin films. The length of the SWCNT film is unlimited, because the as-deposited film is transferred onto a flexible poly(ethylene terephthalate) substrate with the aid of a roll-to-roll transfer system, and the membrane filter can be repeatedly used for the SWCNT film collection. More importantly, as there are no impurities and defects introduced in the production processes, the SWCNT films have an excellent optoelectrical performance including a low sheet resistance of 65 Ω/□ with a transmittance of 90% at a wavelength of 550 nm. Using these SWCNT thin films, all-CNT TFTs and ICs including 101-stage ring oscillators have been constructed that show excellent performance and uniformity.

“The present method enables us first to achieve continuous production including the growth, deposition, transfer and re-deposition of SWCNTs.” the paper’s co-first authors, WANG Bing-Wei and JIANG Song said. “The meter-scale high-quality SWCNT films and the devices fabricated from them will pave the way for future development of large-scale, flexible, and transparent electronics based on SWCNT thin films.”

Figure 1. Preparation of meter-scale SWCNT thin films. a) Schematic showing the apparatus designed for the synthesis, deposition, and transfer of SWCNT films. b) A photograph of the home-made apparatus (scale bar, 0.5 m). c) A SWCNT thin film transferred on a flexible PET substrate with a length of more than 2 m. d) A roll of uniform SWCNT thin film on the PET substrate (scale bar, 0.1 m). e) Finite-element simulation of the dependence of Vout on Vfree for an inlet gas velocity Vin = 0.068 m s-1. f) Simulation results showing a uniform velocity distribution in the gas stream in the filtration system at the equilibrium state. (Image by IMR)

Figure 2. Characterization of the as-prepared SWCNT thin films. a) Transmittance and b) sheet resistance mapping, demonstrating good uniformity of the films. c) A comparison of our SWCNT transparent conductive film with previous results. (Image by IMR)

Figure 3. All-CNT TFTs. a) Photograph of all-CNT TFT device fabricated on a flexible PEN substrate. b) Optical transmittance of the PEN substrate (black line) and the all-CNT device fabricated on the substrate (red line). Inset: optical microscopy image of a buried-gate all-CNT TFT (scale bar, 100 μm). c) Schematic cross-section of a buried-gate all-CNT TFT on a PEN substrate. (Image by IMR)

Figure 4. All-CNT logic gates and ring oscillators. a) Circuit diagram of a two-input XOR logic gate. b) Optical microscopy image of an XOR logic gate fabricated on a flexible PEN substrate (scale bar, 100 μm). c) Input–output characteristics of the XOR logic gate. d) Optical microscopy image of a 101-stage ring oscillator fabricated on a flexible PEN substrate (scale bar, 500 μm). e) Output characteristics of the ring oscillator at VDD = -4.4 V. (Image by IMR)



Chinese Researchers Develop Meter-scale Single-wall Carbon Nanotube Thin Films----Institute of Metal Research, Chinese Academy of Sciences

 

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PUBLIC RELEASE: 6-JUL-2018
Chinese scientists achieve success in nitrogen metallization
CHINESE ACADEMY OF SCIENCES HEADQUARTERS


The team developed its own pulsed-laser heating system and ultra-fast optical detection technology. CREDIT: YAO Jie

A Chinese research team announced it has successfully metallized nitrogen at extreme conditions. This exciting result was published in Nature Communications on July 6.

The team, working at the Institute of Solid State Physics at the Hefei Institutes of Physical Science (CASHIPS), developed its own pulsed-laser heating system and ultra-fast optical detection technology to conduct the experiment.

Nitrogen represents about 78 percent of air by volume. Normally, it maintains in a pretty stable molecular gas state without any color or odor. But nitrogen was expected to present quite different properties with exposure to extreme conditions.

For instance, it is believed to turn into a metal in the core of our Earth, and is considered to be one of the most energetic materials in existence.

For years, scientists have been struggling to synthesize a series of materials with extremely high energy based on nitrogen, especially polymeric and metallic nitrogen.

Moreover, it is especially relevant to explore metallic nitrogen at extremely high pressures and temperatures given the challenges of reliable achievement of another equally important material, metallic hydrogen, which is predicted to be a room-temperature superconductor.

In fact, many attempts were made via a variety of methods in previous studies, such as static pressure research with diamond anvil cell and dynamic pressure studies with a gas gun.

The previous results contributed some specific sights into the "hologram" of pressure-temperature-state corresponding information of nitrogen but limited.

"The key is to understand the whole pressure-temperature conditions concerning the transition from molecular nitrogen to metallic nitrogen," said Alexander Goncharov, a member of China's "Thousand Talent Program," who leads a study team. Goncharov also noted that a particular challenge in this kind of study is the mechanism of insulator-to-metal transition, and the existence and location of the critical point where the transition character changes.

JIANG Shuqing, the first author of the paper as well as a scientist working with CASHIPS, said the team scanned the hologram of the properties of nitrogen at a pretty wide range of extreme conditions from 0 to 170 GPa and up to about 8000 K, using the team's self-developed experimental system.

"This allowed us to determine the pressure-temperature region of metallic nitrogen. It's generally above 125 GPa and 2500 K," said JIANG. "The result provided us detailed information on insulator-to-metal transition in nitrogen."

JIANG said the team believes these observations create a better understanding of the interplay between molecular dissociation, melting, and metallization, thus revealing features that are also common in hydrogen.



Chinese scientists achieve success in nitrogen metallization | EurekAlert! Science News

 

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China-made flow meter to replace foreign versions for oil, gas mining at lower cost
By Liu Xuanzun Source:Global Times Published: 2018/7/10 23:03:40

China has successfully developed an underwater wet gas flow meter that is expected to replace imported ones in the development of deep sea oil and gas fields, its developer said.

Tianjin University's School of Electrical and Information Engineering said the underwater wet gas flow meter is the world's first to use ultrasonic technology.

China will no longer be dependent on foreign underwater flow meters after the domestically-made one is used in two years, Xu Ying, head of the flow meter's development team, told the Global Times.

The meter is crucial to developing deep sea oil gas fields. When extracting oil and gas, they are usually mixed together. The volume of the mixed wet gas must be measured in real time by a flow meter to avoid overflowing caused by low pressure, and to prolong the fields' service life, Xu said.

It is important for China to master related technologies, as about half of the world's oil and gas resources will come from the ocean in the future, Science and Technology Daily reported Tuesday.

Compared to foreign products, which are based on gamma ray technology, the new domestic product is based on ultrasonic technology, which will considerably reduce costs, Xu said.

She added that foreign products usually cost Chinese buyers a few million dollars per unit to import, but the domestic one is expected to only cost about $500,000.

Although the technology behind the flow meter is different, it's functionally the same and the quality is comparable to imported ones, Xu said.

 

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Research gets new impetus
By XU WEI | China Daily | Updated: 2018-07-11 07:33

The State Council's decision to give greater autonomy to researchers has been widely hailed as the country seeks breakthroughs in key technologies.

According to a decision at a State Council executive meeting chaired by Premier Li Keqiang last Wednesday, researchers will be given greater control over their personnel, finance and other resources to boost enthusiasm and inject greater vitality into innovation.

Cheng Shujun, a professor with the School of Medicine at Shanghai Jiao Tong University, said the new measures rolled out by the State Council, China's Cabinet are an indicator of greater trust and respect shown to researchers.

"We have to respect the pursuit of researchers and trust their integrity. Right now too much oversight is being placed on researchers," he said.

It was decided at the meeting that government management of scientific research will be reformed so that no repeated filing of materials is required in the national scientific and technological management information system.

Examinations, evaluations and audits of various kinds will be reduced, and researchers will be allowed to purchase professional services, such as accounting, to free them from tedious chores.

The measures came as Chinese leaders made repeated calls for the country to achieve innovative breakthroughs.

"Right now we should streamline administration more thoroughly to further spur the enthusiasm of researchers and free them from the burdensome approvals and tedious chores," the premier said at the meeting.

More trust and respect will be given to researchers and other experts as well with greater autonomy to use their funds. Researchers will be allowed to change their technical routes on the condition that their research directions and targets remain unchanged, the meeting has decided.

More salary incentives will be offered to researchers who take part in tasks leading to breakthroughs in key technologies, and the annual salary mechanism will be introduced for research team leaders and high-calibre talents.

An evaluation mechanism that prioritizes results and performances will be established. Failure in programs due to uncertain factors in science will be treated differently from those that result from academic misconduct. Fraud and counterfeiting behaviors will be stringently punished.

The percentage of indirect funds for basic research will be improved so that the budget for scientific research programs will be simplified.

Li said at the meeting that the development of science and technology, especially high-end technologies, ultimately depends on brainpower, rather than the purchase of equipment.

"We need to create a more enabling environment for scientists and provide them broader space for exploration," he said.

Li also required officials from relevant central government departments to come up with concrete measures to give researchers greater autonomy.

"The more specific the better," he said.

"It is a barrier as well as a bonanza. We must unlock the various restraints for researchers as early as possible and enable them to devote themselves to their areas of research whole-heartedly," the premier said.

Li Meng, vice-minister of science, told a press briefing on Friday that authorities will introduce a peer review evaluation mechanism for researchers who are devoted to basic research.

Evaluations will also prioritize the quality of papers that researchers publish, rather than the number of papers, as well as their representative works and its contributions and influence.

"The premise of all the measures we rolled out is to give full respect to researchers as well as scientific principles," he said.

Wang Dongjie, a researcher with the Agricultural Information Research Institute of the Chinese Academy of Agricultural Sciences, said it is important to give researchers enough patience and freedom to explore their research directions.

"Currently the research mechanism requires new outcomes each year from researchers.

"It makes it difficult for them to focus on a single direction of research, a prerequisite for achieving innovative results," he said.

He noted that administrative orders weigh too much in scientific research, and it is often the case that researchers are placed under the leadership of officials without much know-how of research areas.

Cheng, the professor, said implementation of the measures decided at the executive meeting is also crucial.

"Innovation can only be fostered by lessening restraints in formalities, improving services for them and freeing their minds," he said.

 

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Snake arm robot debuts at CIROS2018
By Wu Yong | chinadaily.com.cn | Updated: 2018-07-11 15:06

A robot with snake-shaped arms developed by Siasun Robot and Automation Co Ltd. [Photo provided to chinadaily.com.cn]

At the CIROS2018 robot exhibition, Siasun Robot and Automation Co Ltd premiered to the world its newly developed robot with snake-shaped arms, unveiling its uniqueness on the spot.

The company uses the concept of bionics to get inspiration from the dexterity of the snake. The specificity of the shape and its working mode are both completely different from traditional discrete articulated robots. This kind of robot adopts an end-following control method, which greatly improves the flexibility and adaptability of the robot and makes it more suitable for working in extremely harsh conditions.

With 12 joints and 24+1 degrees of freedom, the product can smoothly and flexibly avoid obstacles, and can also be operated by remote control. The product is mainly used in narrow spaces and harsh environments. The robot can use different tools to complete many complex tasks. These include drilling in the narrow environment of the wing rib compartment of aircraft, maintenance of reactor cooling pipelines in nuclear power plants, investigation of military targets over a field of view, and rescuing trapped people at earthquake sites.

 

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Scientists Produce Ultrahigh-charge Relativistic Electron Beams in Laser-solid Interaction
Jul 10, 2018

Laser-plasma based accelerators have undergone rapid development in the last three decades. Owing to the characteristics of plasma, the accelerating gradient of laser-plasma accelerators is thousands of times higher than that of the traditional radio frequency accelerators. This shrinks the kilometer scale large facilities to tabletop, stimulating the study of laser-plasma accelerators worldwide due to the compactness and low cost.

However, currently, the laser-plasma accelerators meet a serious bottleneck. It cannot produce electron beams with high charge and small divergence angle simultaneously.

In laser-gases interaction, the divergence angle can be very small while the beam charge is limited to only tens of picocoulombs. In laser-soild interaction, the beam charge could reach a few nanocoulombs, but with very large divergence angles, unfortunately.

Recently, MA Yong, ZHAO Jiarui, Li Yifei and Li Dazhang in Prof. CHEN Liming and Prof. ZHANG jie's group from Institute of Physics, Chinese Academy of Sciences, have produced relativistic electron beams with extremely high beam charge and small divergence angle.

In their experiment, the super-intense (200 TW) ultra-short (1 ps) Titan laser at Lawrence Livermore National Laboratory was irradiated at copper target, producing relativistic electron beams with an extremely high charge of 100 nanocoulombs level and divergence angle smaller than 3 degrees.

The researchers found out that the generation of such electron beams can be well controlled by adjusting the laser contrast and the laser energy. They also revealed a new electron acceleration mechanism in laser-solid interaction by performing computational numerical simulations.

Owing to the sub-picoseconds pulse duration, the peak current of such electron beams reaches over 100 kA. Moreover, the brightness of the beam can be as high as 1016 A/m2, which is comparable to the highest of traditional accelerators around the world.

If deposit all the energy into high-Z materials, for example, Au, the resulting energy density can be as high as 1012 J/m3. Therefore, this kind of electron beam source could be an ideal tool to drive warm and even hot dense matters.

It might also find wide applications in seeding high-flux γ-ray source, single-shot electron radiography and even serving as an ignitor in fast ignition for inertial confinement fusion.

This study entitled "Ultrahigh-charge electron beams from laser-irradiated solid surface" was published in PNAS.

The study was supported by the National Science Foundation, the Ministry of Science and Technology of China and the Chinese Academy of Sciences.

Fig. 1 Experimental setup. (Image by Institute of Physics)

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Fig.2 Angular distribution of the electron beams. (Image by Institute of Physics)​

Fig. 3 Depends of electron beam charge and divergence angle on laser contrast. (Image by Institute of Physics)

Fig. 4 Numerical simulations. (Image by Institute of Physics)



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Scientists Produce Ultrahigh-charge Relativistic Electron Beams in Laser-solid Interaction---Chinese Academy of Sciences

 

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Wireless Sensors Are To Be Self-Powered And Self-Identified Instantaneously When Triggered Mechanically
by Jikui Luo

Sensors are a type of transducer that can convert, measure, and change information into electrical signals for analysis, monitoring, etc, and can be used to measure the temperature, pressure, etc. of physical variables, such as pH value, gas chemical concentration, glucose concentration, etc., of biochemical variables.

Sensors, particularly wireless sensor networks, are the foundation of the modern Internet of Things (IoT), artificial intelligence, robotics, smart manufacturing, smart buildings, etc, but most of them require electricity to operate and additional electronics for wireless transmission of sensing information and have no identity by themselves. Batteries are commonly used to power wireless sensors, but it requires frequency replacement, which is not a cost-effective or viable/practical method for remote areas or sensors in harsh environments.

Nanogenerator technologies have been explored to power wireless sensors locally by utilizing piezoelectric, pyroelectric, electromagnetic, and triboelectric effects that harvest energy from the ambient environment. However, the existing nanogenerators typically require rectification diodes and energy storage units to store the electricity and to regulate the voltage to power the wireless sensor chip. As a result, nanogenerators have very low power conversion/utilization efficiency. On the other hand, current wireless communication chips require high power to operate, in the order of several milli-watts though in a short period of time, which the nanogenerators are normally unable to meet.

To fulfill the power demand for the wireless sensor chip(s), the nanogenerator embedded in the system needs to work for a relatively long period of time before the wireless transmission process takes place, which results in severe information loss or only a tiny proportion of sensing information that can be sent out for analysis. This becomes even more severe when the nanogenerator performs sensing tasks simultaneously. Although the sensor ID issue can be solved by integrating radio frequency ID (RFID) on the chip or using a special device, such as surface acoustic wave sensor which has ID capability, the ID information can only be obtained through passive triggering.

A new type of instantaneous, self-powered, self-identified wireless sensors have been developed jointly by a group of scientists from China and Britain, by utilizing triboelectric effect/device and resonant circuit integration. The sensor device produces power, wireless sensing, and identity information when it is pressed (triggered) by an external force and then transmits the signal wirelessly. The sensor device has instantaneous energy harvesting, sensing, identity generation and wireless signal transmission four functions simultaneously. The sensor is a standalone device with no need for energy supply, yet it responds to every trigger without losing any sensing information and does not need a rectification circuit, energy storage units, microprocessor, wireless communication, etc; it is totally different from the existing self-powered sensors, or passive RFIDs and surface acoustic wave sensors. It is a true self-powered wireless sensor with identity.

As TENGs are sensitive to force (pressure, stress), vibration, impact, displacement, shape change, humidity, temperature, chemicals of environment, etc, they can be made to be the sensors for the corresponding variable measurements, therefore, potential applications of these type of novel sensors are very broad, and can be used in IoT, intelligent manufacturing, smart infrastructures, agriculture and transportation, automation, security, anti-intruders, head-counting, and games, to name a few, yet the devices are simple in structure and fabrication and can be manufactured by many types of insulator materials at very low cost.

Figure 1. Schematic drawing and an equivalent circuit of the instantaneously self-powered wireless sensors with identity; it consists of a TENG, a micromechanical switch, a resonant circuit and a wireless transmission and reception device.

The device consists of a triboelectric nanogenerator (TENG) which is also a sensor, a capacitor-inductor oscillating circuit in parallel with the TENG and a wireless transmitter. A micromechanical switch is integrated with the TENG which has a synchronized movement with the TENG, but with a reduced period for the TENG to release accumulated charges to boost the voltage and power outputs of the TENG up to 1300V and 800mW, and reduce the output impedance by several orders of magnitudes. These allow output effectively coupled to the oscillating circuit to generate a very strong damping resonant signal (up to VPP=600V) which contains sensing and device identity (resonant frequency) information. The oscillating signal is then coupled to the transmitter (red laser in this work, and could be changed to an RF transmitter) for long distance wireless communication. The scientists have demonstrated the capability of the self-powered sensor for wireless humidity and force (pressure) sensing with the identity attached for up to 5 meters, and the wireless transmission distance can be improved greatly by utilizing better optical alignment, lens, and blue lasers.

These findings are described in the article entitled Triboelectric effect based instantaneous self-powered wireless sensing with self-determined identity, recently published in the journal Nano Energy. This work was conducted by Jinkai Chen (Hangzhou Dianzi University, Zhejiang University), Weipeng Xuan (Hangzhou Dianzi University), Pengfei Zhao (University of Bolton), Umar Farooq, Peng Ding, Hao Jin, Xiaozhi Wang, and Shurong Dong (Zhejiang University), Wuliang Yin (University of Manchester), Yongqing Fu (Northumbria University), and Jikui Luo (Hangzhou Dianzi University, University of Bolton).



Wireless Sensors Are To Be Self-Powered And Self-Identified Instantaneously When Triggered Mechanically | Science Trends

 

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Researchers found evidence of early human ancestors in a cliff-hanger expedition at Shangchen, in the Loess Plateau of China. ZHAOYU ZHU
Our ancestors may have left Africa hundreds of thousands of years earlier than thought
By Ann Gibbons
Jul. 11, 2018 , 1:00 PM

More than 2 million years ago, our ancestors were already world travelers, trekking all the way from Africa to Asia, according to stone tools found on a cliff face in north-central China. The age of the tools suggests that the forebears of modern humans left Africa at least 250,000 years earlier than thought; it also supports a minority view that a key human ancestor, Homo erectus, may have originated in Asia, not in Africa.

Until now, the oldest evidence of human ancestors outside of Africa was in Dmanisi, Georgia. Here, fossils of short people thought to be early H. erectus date back to about 1.85 million years—just after the species appears in Africa. The oldest evidence of early human activity in China and Indonesia has been fossils and stone tools that date to 1.5 million to 1.7 million years ago, including a skullcap of H. erectus from a site just 4 kilometers south of the newly dated tools. This trail of stones and bones has suggested that after the earliest members of our own genus Homo appeared about 2.8 million years ago in Ethiopia, they didn’t leave until 2 million years ago or so—and made it to eastern Asia even later.

Now, evidence from the site of Shangchen, in the Loess Plateau approximately 1200 kilometers southwest of Beijing, is shaking up that view. On the steep cliff faces of a gully at Shangchen, a Chinese team unearthed 96 stone points, flakes, and cores that were probably used to carve up animal bones or to smash them open for marrow. Antelope, deer, and pig bones were found with the tools.

The same team, led by geologist Zhaoyu Zhu of the Guangzhou Institute of Geochemistry at the Chinese Academy of Sciences, spent years nailing down dates for the layers of sediments in which the tools were embedded. The sediments at Shangchen lack volcanic minerals, which provide the gold standard for radiometric dating methods and are plentiful in Africa. Instead, the researchers used paleomagnetic dating—which detects known reversals in Earth’s magnetic field that are recorded in ancient rock—and found that the stone tools range in age from 1.6 million to 2.1 million years ago. This indicates hominins—the family that includes humans and our ancestors—got out of Africa at least a quarter of a million years earlier than thought, and occupied Shangchen on and off for more than 850,000 years, the team reports today in Nature.

This quartzite flake tool dates back to more than 2 million years in China. ZHAOYU ZHU

“The dates are convincing,” says geochronologist Andrew Roberts of the Australian National University in Canberra, who was not part of the team. Geoarchaeologist Reid Ferring of the University of North Texas in Denton, who dated the Dmanisi site, says the paper makes a “good case for occupations older than Dmanisi.”

Another key finding is that the new dates show that “already before 2 million years, hominins were able to cope with a range of environmental conditions,” says archaeologist Wil Roebroeks of Leiden University in the Netherlands, who is not a member of the team. During the long span of occupations at Shangchen, which is about the same latitude as Kabul, the climate fluctuated from warm and wet to cold and dry. “They must have been freezing their buns off,” adds paleoanthropologist Rick Potts of the Smithsonian Institution’s National Museum of Natural History in Washington, D.C.

The early dates suggest hominins were already remarkably adaptable by 2.1 million years ago—even though they had not yet evolved the even bigger brains, long legs, or more advanced tools like hand axes seen in later humans. Although the identity of these early globetrotters is unknown, the new dates raise the possibility that H. erectus wasn’t the first hominin to leave Africa. Chinese and Georgian scholars have long argued that a more primitive species of hominin got out of Africa and gave rise to H. erectus in Asia. And now, these early tools show hominins were in China far before H. erectus appeared in Africa—and early enough for a new species to evolve. In fact, “H. erectus may have evolved in Eurasia and migrated to Africa,” Ferring says.


Our ancestors may have left Africa hundreds of thousands of years earlier than thought | Science | AAAS

Zhaoyu Zhu, Robin Dennell, Weiwen Huang, Yi Wu, Shifan Qiu, Shixia Yang, Zhiguo Rao, Yamei Hou, Jiubing Xie, Jiangwei Han, Tingping Ouyang. Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago. Nature (2018). DOI: 10.1038/s41586-018-0299-4​

 

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Mice Study Implicates Fat as Obesity Cause
Jul 13, 2018

What we eat plays a big role in our ability to regulate our body weight. Over time, however, different ideas have emerged about the most important dietary factors that cause us to put on weight.

During the 1980s and 1990s, it was widely accepted that the most important factor in weight gain is the fat content of our diets. However, in the new millennium it was suggested that this focus on fat was misplaced, and that, in fact, the main factor driving obesity was our carbohydrate intake – notably, our intake of refined carbohydrates like sugars.

Several hugely popular books were published in this period suggesting that eating fat might actually protect us from obesity.

Most recently, however, attention has turned to protein, with the hypothesis that people eat food mostly to obtain protein rather than energy.

According to this idea, when the protein content of our diet falls, we eat more food to meet our target protein intake. That makes us consume too many calories and we get fat. Since our food consists of fat, protein and carbohydrates – and at different times all three have been implicated in making us obese – it is difficult to know what to eat to stay slim.

Part of the problem is that it is very difficult to do human studies that control food intake long enough to determine what dietary factors cause weight gain. Studies on animals similar to us, however, can suggest possible answers.

Now scientists at the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences in Beijing and the University of Aberdeen in Scotland have performed the largest study of its kind to resolve what components of the diet cause mice to put on body fat. The study was published today in the journalCELL Metabolism.

The study included 30 different diets that varied in their fat, carbohydrate (sugar) and protein contents. Mice of five different strains were fed these diets for 3 months, which is equivalent to 9 years in humans.

In total, over 100,000 measurements were made of the mice’s body weight changes and their body fat was measured using a micro MRI machine. The result of this enormous study was unequivocal – the only thing that made the mice get fat was eating more fat in their diets. Carbohydrates, including up to 30% of calories coming from sugar, had no effect.

Combining sugar with fat had no more impact than fat alone. There was no evidence that low protein (down to 5% of the total calories) stimulated greater intake, suggesting there is no protein target. The researchers believe that dietary fat caused weight gain because fat in the diet uniquely stimulated the reward centers in the brain, thus causing greater intake of calories.

Professor John Speakman, who led the study, said "A clear limitation of this study is that it is based on mice rather than humans. However, mice have lots of similarities to humans in their physiology and metabolism, and we are never going to do studies where the diets of humans are controlled in the same way for such long periods. So the evidence it provides is a good clue to what the effects of different diets are likely to be in humans."


Mice Study Implicates Fat as Obesity Cause---Chinese Academy of Sciences

Sumei Hu, Lu Wang, Dengbao Yang, Li Li, Jacques Togo, Yingga Wu, Quansheng Liu, Baoguo Li, Min Li, Guanlin Wang, Xueying Zhang, Chaoqun Niu, Jianbo Li, Yanchao Xu, Elspeth Couper, Andrew Whittington-Davies, Mohsen Mazidi, Lijuan Luo, Shengnan Wang, Alex Douglas, John R. Speakman. Dietary Fat, but Not Protein or Carbohydrate, Regulates Energy Intake and Causes Adiposity in Mice. Cell Metabolism (2018). DOI: 10.1016/j.cmet.2018.06.010
​

Credit: Cell Press​

 

[JSCh]

15 Sri Lankan students awarded scholarships to study oceanology, marine sciences in China
Source: Xinhua| 2018-07-12 16:41:38|Editor: huaxia


COLOMBO, July 12 (Xinhua) -- Fifteen Sri Lankan university students have been awarded scholarships by the Chinese Academy of Sciences (CAS) to pursue higher studies on climatology and oceanography in a bid to strengthen the education ties between China and Sri Lanka.

The scholarships were handed over on Wednesday under the "Belt and Road" Master Fellowship Program. The program was operated by the China-Sri Lanka Joint Center for Education and Research (CSL-CER), which is based on the South China Sea Institute of Oceanology of the CAS.

Out of the 15 students, three students have been awarded scholarships to pursue their PhD degree while the remaining 12 will pursue their master's degree.

This is the third year that the CAS has awarded these scholarships to Sri Lankan university students.

The students this year are selected from the University of Ruhuna, the University of Peradeniya, the University of Sabaragamuwa, the University of Jaffna and the University of Wayamba.

Speaking at the handing over ceremony, Professor. Gamini Senanayake, vice chancellor of the University of Ruhuna, said it was vital that Sri Lankan students pursue their higher studies in oceanography, as Sri Lanka being an island country deepens mostly on its sea.

However, he said Sri Lanka lacked the human resources to explore the opportunities of the ocean.

As Sri Lanka also faced natural hazards such as heavy rains every year followed by strong winds, it was vital that Sri Lanka studied the ocean surrounding it, Senanayake said.

"Being a very friendly nation, China has always helped us in various fields and especially the Chinese Academy of Sciences has a very big programme ongoing with Sri Lanka. We thank them for that as it benefits our students," Senanayake said.

Professor Mohan de Silva, Chairman of the University Grants Commission, said it was important for Sri Lankan students to pursue a higher education in marine sciences and oceanography, as it would benefit the island country.

"We are glad that the University of Ruhuna along with the CAS is taking efforts to develop this expertise in this country," de Silva said.

Rivindu Vithana, a PhD student awarded the scholarship, said it was a great honour for her to be accepted to study in a prestigious Chinese university. She assured that she would use this opportunity diligently and with care to enhance her knowledge.

 

[JSCh]

Single-celled architects inspire new nanotechnology
July 16, 2018

Diatoms are tiny, unicellular creatures, inhabiting oceans, lakes, rivers and soils. Through their respiration, they produce close to a quarter of the oxygen on Earth, nearly as much as the world’s tropical forests. In addition to their ecological success across the planet, they have a number of remarkable properties. Diatoms live in glasslike homes of their own design, visible under magnification in an astonishing and aesthetically beautiful range of forms.

Researchers have found inspiration in these microscopic, jewel-like products of nature since their discovery in the late 18th century. In a new study, Arizona State University scientists led by Professor Hao Yan, in collaboration with researchers from the Shanghai Institute of Applied Physics of the Chinese Academy of Sciences and Shanghai Jiaotong University led by Professor Chunhai Fan, have designed a range of diatom-like nanostructures.

A selection of nanostructures built using DNA origami, alongside naturally occurring diatoms — single-celled organisms that come in many beautiful and elaborate forms. They are ubiquitous inhabitants of the world's lakes, rivers and oceans. A scale shows the sizes of the nanostructures and diatoms. Graphic by Shireen Dooling

To achieve this, they borrow techniques used by naturally occurring diatoms to deposit layers of silica — the primary constituent in glass — in order to grow their intricate shells. Using a technique known as DNA origami, the group designed nanoscale platforms of various shapes to which particles of silica, drawn by electrical charge, could stick.

The new research demonstrates that silica deposition can be effectively applied to synthetic, DNA-based architectures, improving their elasticity and durability. The work could ultimately have far-reaching applications in new optical systems, semiconductor nanolithography, nano-electronics, nano-robotics and medical applications, including drug delivery.

Yan is the Milton D. Glick Distinguished Professor of Chemistry and Biochemistry and directs the Biodesign Center for Molecular Design and Biomimetics. The group’s findings are reported in the advanced online of the journal Nature.

Researchers like Yan and Fan create sophisticated nanoarchitectures in two and three dimensions, using DNA as a building material. The method, known as DNA origami, relies on the base-pairing properties of DNA’s four nucleotides, whose names are abbreviated A,T, C and G.

The ladder-like structure of the DNA double helix is formed when complementary strands of nucleotides bond with each other — the C nucleotides always pairing with Gs and the As always pairing with Ts. This predictable behavior can be exploited in order to produce a virtually limitless variety of engineered shapes, which can be designed in advance. The nanostructures then self-assemble in a test tube.

Base-pairing properties of DNA were used to construct tiny structures that accumulated a silica outer skeleton similar to shell-building organisms known as diatoms. Image courtesy of the Yan Lab

In the new study, researchers wanted to see if architectures designed with DNA, each measuring just billionths of a meter in diameter, could be used as structural frameworks on which diatom-like exoskeletons composed of silica could grow in a precise and controllable manner. Their successful results show the power of this hybrid marriage of nature and nanoengineering, which the authors call DNA Origami Silicification (DOS).

“Here, we demonstrated that the right chemistry can be developed to produce DNA-silica hybrid materials that faithfully replicate the complex geometric information of a wide range of different DNA origami scaffolds. Our findings established a general method for creating biomimetic silica nanostructures,” Yan said.

Among the geometric DNA frameworks designed and constructed in the experiments were 2D crosses, squares, triangles and DOS-diatom honeycomb shapes as well as 3D cubes, tetrahedrons, hemispheres, toroid and ellipsoid forms, occurring as single units or lattices.

Once the DNA frameworks were complete, clusters of silica particles carrying a positive charge were drawn electrostatically to the surfaces of the electrically negative DNA shapes, accreting over a period of several days, like fine paint applied to an eggshell. A series of transmission- and scanning-electron micrographs were made of the resulting DOS forms, revealing accurate and efficient diatom-like silicification.

The method proved effective for silicification of framelike, curved and porous nanostructures ranging in size from 10-1000 nanometers (the largest structures are roughly the size of bacteria). Precise control over silica shell thickness is achieved simply by regulating the duration of growth.

The hybrid DOS-diatom nanostructures were initially characterized using a pair of powerful tools capable of unveiling their tiny forms, Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM). The resulting images reveal much clearer outlines for the nanostructures after the deposition of silica.

The method of nanofabrication is so precise, researchers were able to produce triangles, squares and hexagons with uniform pores measuring less than 10 nm in diameter — by far the smallest achieved to date, using DNA origami lithography. Further, the technique outlined in the new study equips researchers with more accurate control over the construction of 3D nanostructures in arbitrary forms that are often challenging to produce through existing methods.

One property of natural diatoms of great interests to nanoengineers like Yan and Fan is the specific strength of their silica shells. Specific strength refers to a material’s resistance to breakage relative to its density. Scientists have found that the silica architectures of diatoms are not only inspiringly elegant but exceptionally tough. Indeed, the silica exoskeletons enveloping diatoms have the highest specific strength of any biologically produced material, including bone, antlers and teeth.

In the current study, researchers used AFM to measure the resistance to breakage of their silica-augmented DNA nanostructures. Like their natural counterparts, these forms showed far greater strength and resilience, displaying a 10-fold increase in the forces they could withstand, compared with the unsilicated designs, while nevertheless retaining considerable flexibility.

The study also shows that the enhanced rigidity of DOS nanostructures increases with their growth time. As the authors note, these results are in agreement with the characteristic mechanical properties of biominerals produced by nature, coupling impressive durability with flexibility.

A final experiment involved the design of a new 3D tetrahedral nanostructure using gold nanorods as supportive struts for a DOS fabricated device. This novel structure was able to faithfully retain its shape compared with a similar structure lacking silication that deformed and collapsed.

The research opens a pathway for nature-inspired innovations in nanotechnology in which DNA architectures act as templates that may be coated with silica or perhaps other inorganic materials, including calcium phosphate, calcium carbonate, ferric oxide or other metal oxides, yielding unique properties.

“We are interested in developing methods to create higher-order hybrid nanostructures. For example, multi-layered/multi-component hybrid materials may be achieved by a stepwise deposition of different materials to further expand the biomimetic diversity,” Fan said.

Such capabilities will open up new opportunities to engineer highly programmable solid-state nanopores with hierarchical features, new porous materials with designed structural periodicity, cavity and functionality, plasmonic and meta-materials. The bio-inspired and biomimetic approach demonstrated in this paper represents a general framework for use with inorganic device nanofabrication that has arbitrary 3D shapes and functions and offers diverse potential applications in fields such as nano-electronics, nano-photonics, and nano-robotics.

This project was supported by National Science Foundation of China (21390414, 21329501, 21603262 and 21675167), National Key R&D Program of China (2016YFA0201200, 2016YFA0400900), Key Research Program of Frontier Sciences, CAS (QYZDJ-SSW-SLH031). L.W., C.F. and H.Y. thank National Key R&D Program of China (2016YFA0400900) and UCB Pharma, H.Y, F.Z and Y. L. thank funding from US National Science Foundation, Office of Naval Research, Army Research Office, National Institutes of Health, and Department of Energy for financial supports.



Single-celled architects inspire new nanotechnology | ASU Now: Access, Excellence, Impact

Xiaoguo Liu, Fei Zhang, Xinxin Jing, Muchen Pan, Pi Liu, Wei Li, Bowen Zhu, Jiang Li, Hong Chen, Lihua Wang, Jianping Lin, Yan Liu, Dongyuan Zhao, Hao Yan, Chunhai Fan. Complex silica composite nanomaterials templated with DNA origami. Nature (2018); DOI: 10.1038/s41586-018-0332-7​

 

[JSCh]

Scientists Develop New Generation of Deep-ultraviolet Nonlinear Optical Materials
Jul 17, 2018

KBe2BO3F2 (KBBF) has been the only practically usable deep ultraviolet (DUV) nonlinear optical (NLO) crystal so far that can generate DUV coherent light by the direct second harmonic generation. However, the commercial production and applications are hindered by its layering habit.

Recently, Prof. YE Ning’s group at Fujian Institute of Research on the Structure of Matter of Chinese Academy of Sciences designed and synthesized two new excellent DUV NLO crystals NH4Be2BO3F2(ABBF) and γ-Be2BO3F (γ-BBF) based on the structure of KBBF. The results were published in Angew. Chem. Int. Ed.

These two crystals were found to perfectly inherit the favorable structure merits of KBBF.

For ABBF, the N-H···F hydrogen bonds were found to effectively overcome the layering habit. As to γ-BBF, the in-site excision of A-site atoms (NH4+ or K+) was found to make the adjacent layers bridged directly by Be-F ionic bond, showing strong interlayer bonding.

Besides, they revealed that the UV cut-off edges, birefringences and second-harmonic generation effects of ABBF and γ-BBF are very close to or even better than KBBF, making their shortest type I phase-matching (PM) second-harmonic wavelength (λPM) down to 173.9 nm and 146 nm, respectively.

Their excellent DUV laser output potential demonstrated a breakthrough in the field of deep ultraviolet nonlinear optical crystal.


Scientists Develop New Generation of Deep-ultraviolet Nonlinear Optical Materials---Chinese Academy of Sciences

 

[JSCh]

Snake arm robot debuts at CIROS2018
By Wu Yong | chinadaily.com.cn | Updated: 2018-07-11 15:06

A robot with snake-shaped arms developed by Siasun Robot and Automation Co Ltd. [Photo provided to chinadaily.com.cn]

At the CIROS2018 robot exhibition, Siasun Robot and Automation Co Ltd premiered to the world its newly developed robot with snake-shaped arms, unveiling its uniqueness on the spot.

The company uses the concept of bionics to get inspiration from the dexterity of the snake. The specificity of the shape and its working mode are both completely different from traditional discrete articulated robots. This kind of robot adopts an end-following control method, which greatly improves the flexibility and adaptability of the robot and makes it more suitable for working in extremely harsh conditions.

With 12 joints and 24+1 degrees of freedom, the product can smoothly and flexibly avoid obstacles, and can also be operated by remote control. The product is mainly used in narrow spaces and harsh environments. The robot can use different tools to complete many complex tasks. These include drilling in the narrow environment of the wing rib compartment of aircraft, maintenance of reactor cooling pipelines in nuclear power plants, investigation of military targets over a field of view, and rescuing trapped people at earthquake sites.