Error Source of a Sea-ice Model Varies with Season: Study (Earth Science)

Arctic sea-ice has been rapidly declining in recent decades, which can exert significant impacts on global weather and climate through interactions with the atmosphere and oceans. In addition, the Arctic shipping routes are a shortcut to connect major countries in the Northern Hemisphere. The Arctic region is also rich in natural resources and biological resources.

Schematic diagram of the sea-ice simulation error sources of a regional configuration of MITgcm (Image by SUN Yue)

Simulation of the Arctic sea-ice can provide valuable information for Arctic shipping as well as climate studies. Therefore, it is urgent to evaluate the ability to simulate Arctic sea-ice and diagnose the sources of simulation errors.

A research team led by Prof. ZHENG Fei from the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences evaluated the sea-ice simulations of the Arctic regional ocean-ice coupling configuration of the Massachusetts Institute of Technology general circulation model (MITgcm) to address the issue of error source identification.

“We evaluated the model’s performance in the Arctic cold season (March) and warm season (September), and found the model performances are different in the two months,” said Prof. ZHENG. “Due to the uncertainty of the model, the model’s insufficient response to the signal of atmospheric forcings, and the insufficient response to the ocean boundary signal, there were disagreements between the simulations and observations in both March and September.”

According to their paper published in Advances in Atmospheric Sciences, the characteristics of seasonally varying model error sources could be fully considered by means of an ensemble approach, so as to achieve the goal of improving the simulation and prediction of Arctic sea-ice in different seasons in future work.

Reference: Zheng, F., Sun, Y., Yang, Q. et al. Evaluation of Arctic Sea-ice Cover and Thickness Simulated by MITgcm. Adv. Atmos. Sci. 38, 29–48 (2021). https://link.springer.com/article/10.1007/s00376-020-9223-6 https://doi.org/10.1007/s00376-020-9223-6

Provided by Chinese Academy of Sciences

Waste to Treasure: Crayfish Shells to Store Energy (Biology)

As a spicy night snack in China, the crayfish has showed its great potential in the energy sector. Prof. ZHU Xifeng’s team from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) made it possible to use crayfish shell as the biological template for high-performance supercapacitors. This work was published on Carbon.

From shell and high fraction of bio-oil (HB), the supercapacitor material hierarchical porous carbons (HPCs) are made. (Image by LUO Zejun et al.)

Compared with other high-performance materials, biomass has long been regarded as promising for its environmental-friendliness and extensive resources. However, practical application of biomass is restricted by their relatively rare efficient storage sites, low diffusion kinetics and the need for huge amount of premade nano templates.

To solve the problems, the researchers innovatively introduced crayfish shells to get the biological template.

Shells were dried, ground and pretreated in an alkaline solution to retrieve templates, which were then mixed with the heavy fraction of bio-oil derived from agricultural waste to manufacture hierarchical porous carbons, a kind of supercapacitor material.

The compounded product delivered magnificent capacitance of 351 F/g thanks to its ultrahigh specific surface area, large total pore volume and reasonable content of oxygen atoms, which are of importance to a capacitor.

Besides, the symmetric supercapacitors assembled by the synthetic samples showed a superior energy density of 20 Wh/kg at a power density of 350W/kg, preceding other biomass materials.

This method possesses an environmentally friendly solution for the power storage problem of the rapid-growing wearable displays, electric vehicles and smartphones.

Reference: Zejun Luo, Ning Lin, Mengchao Sun, Yusong Wang, Xifeng Zhu, “Synthesis of 3D-interconnected hierarchical porous carbon from heavy fraction of bio-oil using crayfish shell as the biological template for high-performance supercapacitors”, Carbon, Volume 173, 2021, Pages 910-917, ISSN 0008-6223,
https://doi.org/10.1016/j.carbon.2020.11.083.
http://www.sciencedirect.com/science/article/pii/S0008622320311623

Provided by University of Science and Technology of China

Experiments First Verify Distributed Quantum Phase Estimation (Quantum)

Prof. PAN Jianwei and colleages from University of Science and Technology of China (USTC) of the Chinese Academy of Sciences (CAS) have achieved experimental verification of distribution quantum phase estimation for the first time. This work, which “constitutes a significant milestone” by the reviewer, was published on Nature Photonics.

Distributed metrology is a key tool to measure several locations from remote simultaneously with high precision, one typical task of which is the monitoring on stress field and temperature field of bridge and airplane.

In line with the development of quantum technology, metrology also entered quantum era. When targeting on measurement of multiple parameters distributed in space, distributed quantum metrology can enhance the sensitivity of measurements beyond the classical limits.

However, researchers are wondering how to achieve entangled states for optimal precision of multiparameter measurement, which was known as the ultimate Heisenberg limit.

In this study, PAN’s team designed the optimal measurement scheme using entangled photons, and demonstrated measurement of individual phase shifts and their average. The precision went beyond the theory limit of classical sensor.

Experimental setup on distributed estimation of quantum phase. (Image by LIU Lizheng et al.)

By considering both photon entanglement and coherence, Prof. PAN’s team further demonstrated linear combination of multiple phase shifts with the total number of parameters to measure up to 21. This combined scheme both enlarged the number of measurable parameters and enhanced the precision compared with using photon entanglement only.

This research assessed the precision of measurement in different entanglement strategies and provided the verification of the benefit of entanglement and coherence for distributed quantum metrology. It lays a foundation for future application of high-precision distributed quantum metrology.

Reference: Liu, LZ., Zhang, YZ., Li, ZD. et al. Distributed quantum phase estimation with entangled photons. Nat. Photonics (2020). https://www.nature.com/articles/s41566-020-00718-2 https://doi.org/10.1038/s41566-020-00718-2

Provided by University of Science and Technology of China

Combined Approach Could Boost Breast Cancer Immunotherapy, Study Suggests (Medicine)

Activating an immune signaling pathway best known for fighting viral and bacterial infections can boost the ability of genetically engineered T cells to eradicate breast cancer in mice, according to a new study by researchers at the University of North Carolina. The study, to be published December 31 in the Journal of Experimental Medicine (JEM), suggests that CAR T cells, which are already used to treat certain blood cancers in humans, may also be successful against solid tumors if combined with other immunotherapeutic approaches.

A diagram showing the various strategies that could enhance the activity of CAR T cells against breast cancer. © 2020 Xu et al. Originally published in Journal of Experimental Medicine. https://doi.org/10.1084/jem.20200844

Chimeric antigen receptor (CAR) T cells are a type of white blood cell that have been genetically engineered to recognize and attack cancer cells expressing specific proteins on their surface. They have been successfully used to treat patients with B cell lymphomas and are currently undergoing clinical trials for the treatment of many other types of blood cancer. “However, the clinical activity of CAR T cells in patients or animal models with solid tumors has been modest,” says Jonathan S. Serody, the Elizabeth Thomas Professor of Medicine, Microbiology, and Immunology and Director of the Cellular Therapy Program at the University of North Carolina School of Medicine.

CAR T cells may be less effective against solid tumors because they have to migrate into the tumors and then survive long enough to kill all of the tumor cells. Moreover, the cells and molecules surrounding tumors are often immunosuppressive, activating an immune checkpoint that causes the CAR T cells to lose their activity.

In the new study, Serody and colleagues tested several strategies to boost the effectiveness of CAR T cells in a mouse model of breast cancer. One effective strategy was to simultaneously treat the mice with drugs, such as cGAMP, that activate the STING pathway, an immune cell signaling pathway that normally induces inflammation in response to invading viruses or bacteria. Activating the STING pathway created a proinflammatory environment within the mouse tumors, improving the CAR T cells’ ability to accumulate and attack the tumor cells. The accumulation was particularly great when the mice were infused with CAR T cells that produce the immune signaling molecule IL-17A, compared with CAR T cells generated using standard techniques.

Serody and colleagues determined that the CAR T cells’ attack could be sustained for longer periods if the mice were also treated with therapeutic antibodies that deplete immunosuppressive cells from the tumor environment and prevent the immune checkpoint from deactivating the CAR T cells. The researchers found that combining all of these approaches led to the complete eradication of breast tumors.

“cGAMP is in clinical trials for the treatment of patients with cancer, there are multiple ongoing clinical trials using approaches to inhibit immunosuppressive cells for patients with malignant disease, and there are clinical trials currently evaluating the combination of CAR T cells with immune checkpoint blockade,” Serody says. “Together therefore, our data suggest a viable strategy for boosting CAR T activity in solid tumors.”

Reference: Nuo Xu, Douglas C. Palmer, Alexander C. Robeson, Peishun Shou, Hemamalini Bommiasamy, Sonia J. Laurie, Caryn Willis, Gianpietro Dotti, Benjamin G. Vincent, Nicholas P. Restifo, Jonathan S. Serody; STING agonist promotes CAR T cell trafficking and persistence in breast cancer. J Exp Med 1 February 2021; 218 (2): e20200844. doi: https://doi.org/10.1084/jem.20200844 https://rupress.org/jem/article-abstract/218/2/e20200844/211644/STING-agonist-promotes-CAR-T-cell-trafficking-and?redirectedFrom=fulltext

Provided by Rockefeller University Press

St Petersburg University Scientists Discover an Ancient Island Arc in the Kyrgyz Tien Shan

Researchers have discovered in the Tien Shan mountains a specific complex of rocks that formed in the Cambrian ocean about 500 million years ago.

The scientists from St Petersburg University began to study the geology of Central Asia in the middle of the 20th century. Multi-year research and rich field experience have made it possible to create the world’s leading school of thought in the geology of the Tien Shan at the University. At present, work continues with active collaboration with scientists throughout the world.

(a) Tectonic units of the Tien Shan in Kyrgyzstan; (b) schematic geological map of the Songkultau area © SPbU

One of the recent discoveries of the international research team is the discovery of this specific rock assemblage that is characteristic of modern oceanic island arcs. The rocks of this complex, found in the Songkultau Mountains in Kyrgyzstan, were formed in the Cambrian ocean about 500 million years ago. This is confirmed by the find of adakites. These are the rocks first described from Adak Island, which is part of the Aleutian island arc in the North Pacific Ocean.

‘Studying the conditions of formation of ancient rocks is necessary not only for a better understanding of the geological history of the region. It is important to know this for more practical purposes, especially given that large ore deposits are often associated with adakites, an example of which are the famous copper and gold deposits in Chile,’ said Dmitry Konopelko, Head of the research team, Associate Professor at St Petersburg University.

Double rainbow over ancient island arc assemblages discovered in the Tien Shan mountains © SPbU

The unique composition of Songkultau granites captured the scientists’ attention during regional mapping work carried out in 2007. According to Professor Reimar Seltmann, Head of the Centre for Russian and Central Eurasian Mineral Studies (CERCAMS) at the Natural History Museum in London, this prompted additional research, which led to the discovery of previously unknown fragments of the island arc complex. Professor Johan De Grave from Ghent University in Belgium and Professor Stijn Glorie from the University of Adelaide in Australia were involved in field work in the Tien Shan mountains. Analytical measurements and processing of field data were carried out by: Inna Safonova, a research associate at Novosibirsk State University; and Alla Dolgopolova from the Natural History Museum London. They did it under the guidance of Professor Min Sun in the laboratories of the University of Hong Kong.

The discovery of previously unknown fragments of an ancient island arc in the Kyrgyz Tien Shan is only one of the recent discoveries made within the framework of current projects: IGCP 662 Project ‘Orogenic Architecture and Crustal Growth from Accretion to Collision’ and grant from the Ministry of Education and Science of the Russian Federation 4.Y26.31.0018. They are aimed at deciphering the structures of the Central Asian Orogenic Belt, which is one of the largest ancient mountain systems on Earth.

Reference: http://dx.doi.org/10.1016/j.gsf.2020.08.006

Provided by Saint Petersburg State University

Bionic Idea Boosts Lithium-ion Extraction (Chemistry)

Lithium is an energy-critical element that is considered to be a geopolitically significant resource. However, the supply of lithium may not be enough to meet continuously increasing demand. As a result, scientists are looking for new ways to extract lithium ions.

Metal ion sieving using a bioinspired nanochannel membrane (Image by XIN Weiwen)

Ion selective membranes have already been used extensively for water treatment and ion sieving in electrodialysis technology. However, conventional membranes exhibit low and useless Li⁺ selectivity, making them insufficient for meeting industry requirements.

Chinese scientists have recently made progress in the preparation and application of a bioinspired material that is capable of achieving controlled ion transport and sieving, especially for lithium-ion extraction.

This work, published in Matter, was completed by Prof. WEN Liping’s team at the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences and Prof. ZHANG Qianfan’s team from Beihang University.

In this research, scientists utilized nanofibers, such as from natural silk and polyethyleneimine, to decorate 2D nanosheets. Inspired by the biological structure in nature, the 2D nanosheets are self-assembled layer-by-layer to form a nacre-like stacked structure. The composited membrane acts as an ion-gating heterojunction with opposite charges and asymmetrical nanochannels.

“To be more detailed, the composited membrane shows higher toughness than other reported materials and natural nacre structures. The membrane is also able to efficiently control interlayer spacing and achieve stable ordered nanostructures,” said Prof. WEN.

The typical brick-and-mortar structure formed by nanofibers and nanosheets exhibits a long-time use in solutions. Meanwhile, the confined dehydration and charge-exclusion effects conduct Li⁺ through composited channels rapidly.

Experimental and theoretical results indicate Li⁺ shows an excellent permeation rate that is far higher than Na⁺, K⁺, Mg²⁺ and Ca²⁺ due to its small radius and low charge. Compared with mobilities in bulk, Li⁺ remains basically consistent with the bulk value. In stark contrast, other ions become less mobile than Li⁺ in bulk.

The methodology of using tailor-made 2D membranes with chemical, geometrical, and electrostatic heterostructures allows further exploration of nanofluidic phenomena inside nanochannel membranes for water treatment or power generation.

This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, and the Strategic Priority Research Program of the Chinese Academy of Sciences.

References: Weiwen Xin, Chao Lin, Lin Fu, Qianfan Zhang, Lei Jiang, Liping Wen, “Nacre-like Mechanically Robust Heterojunction for Lithium-Ion Extraction”, Matter, 2020. https://doi.org/10.1016/j.matt.2020.12.003 https://www.cell.com/matter/fulltext/S2590-2385(20)30672-X?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS259023852030672X%3Fshowall%3Dtrue

Provided by Chinese Academy of Sciences

Half-aperture Prototype of Superconducting Combined-function Magnet Completes Cryogenic Test

The half-aperture Canted-Cosine-Theta (CCT) superconducting Quadrupole-Sextupole-Combined-Function magnet prototype, which is independently developed by the High Intensity heavy-ion Accelerator Facility (HIAF) team, has completed its first time full-load current excitation test on December 25.

Fig.1. The half-aperture prototype of superconducting combined-function CCT magnet. (Image by LIANG Yu)

The prototype reached the design value of 500A for quadrupole coil and of 385A for sextupole coil respectively. Its magnetic field gradient and field quality also reach the design values, according to researchers from the Institute of Modern Physics.

The success of the prototype indicates the feasibility and reliability of the CCT-type combined-function magnet structure and technology.

As a high energy fragment separator with the maximum magnetic rigidity of 25Tm, HIAF Fragmentation Separator will apply the innovative CCT combined-function magnet technology. The CCT superconducting magnet is thus one of the key technologies of HIAF.

Fig.2. Cryogenic test site of the prototype. (Image by MEI Enming)

The successful development and testing of the half-aperture prototype indicate that the project team has mastered the core technology of former fabrication, coil winding and epoxy impregnation.

The technical prototype has also laid a good foundation for the batch processing of CCT superconducting magnets and is of great significance for the advancement of high-energy and miniaturization of heavy-ion accelerator devices in the future.

Provided by Chinese Academy of Sciences

Researchers Reveal Effects of Magnetic Activity on Mass Transfer of Binary (Astronomy)

Algol-type binary systems consist of a B-A-F type main-sequence primary component and an F-G-K type giant or subgiant secondary component.

© Xiang Dong et al.

According to the explanation of the Algol paradox, the initially more massive component evolves to fill the Roche lobes first and transfer material to another component, which results in the inversion of mass ratio and the formation of the Algol-type systems. Hence, mass transfer plays an important role in the evolution of this kind of binary system.

A research team led by Prof. QIAN Shengbang from the Yunnan Observatories of the Chinese Academy of Sciences analyzed the magnetic activity of interacting binaries and revealed its effects on the mass transfer of the binary. The study was published in The Astronomical Journal on Dec. 23.

The researchers analyzed the binary system KIC 06852488. Its primary component is a δ Sct-type pulsating star in the main-sequence stage, and its secondary component is a late-type component with a strong magnetic activity.

They found that the variation of the two maxima in the light curve was related with a same cycle length ~2000 days and a 180°phase difference, and the variation of the secondary maxima coincided with the O-C curve of primary light minima.

“The variation of light curve of KIC 06852488 is strongly correlated with the variation of O-C curve,” said SHI Xiangdong, first author of the study.

After analyzing the Kepler and Transiting Exoplanet Survey Satellite (TESS) light curves, the researchers detected that this binary is a semi-detached system with a mass ratio 0.46. The secondary component is filling its critical Roche lobe.

“The variation of the O’Connell effect could be explained by an evolving hot spot on the primary component and an evolving cool spot on the secondary component, and their positions are almost symmetrical with the inner Lagrange L1 point,” said Prof. QIAN. This reveals that the mass transfer of the binary may be related to the magnetic activity.

The flares, pulsation of component, mass transfer and spot activity make the system a natural astrophysics laboratory for studying the interaction of binary mass transfer, stellar pulsation and magnetic activity.

Reference: Xiang-dong Shi, Sheng-bang Qian, Lin-jia Li, and Nian-ping Liu, “Flaring and Spot Activities on the Semi-detached Binary System KIC 06852488”, AJ 161 (46), 2020. https://iopscience.iop.org/article/10.3847/1538-3881/abccd7

Provided by Chinese Academy of Sciences

3D Simulation Helps Revealing Accretion Process in Progenitor of Tycho’s Supernova (Astronomy)

Dr.JIAO Chengliang from Yunnan Observatories of the Chinese Academy of Sciences, collaborating with Prof. XUE Li’s group from Xiamen University, performed three-dimensional (3D) simulations of the accretion flow in the progenitor of Tycho’s supernova, which helps identifying the physical properties of the accretion process.

Images of density at the final time of the simulation run for B = 5.44×10³G. (Image by JIAO Chengliang)

The study was published in Monthly Notices of the Royal Astronomical Society on Nov. 27.

Type Ia supernovae (SNe Ia) plays an important role in astrophysics, especially in cosmology and galactic chemical evolution. SNe Ia can be triggered by a carbon-oxygen white dwarf (CO WD) accreting sufficient material from a non-degenerate companion star, i.e. the single-degenerate (SD) model.

Tycho’s supernova (SN) is a famous SN. Recent observations of its remnant suggests that the SN ejecta should have evolved in a bubble blown by a latitude-dependent wind, yet how this wind is formed is still not very clear.

The researchers studied the wind structure in different situations. They found that when the magnetic field in the accreted material was negligible, outflowing wind was concentrated near the equatorial plane. When the magnetic field had energy equipartition with internal energy, polar wind was comparable with the equatorial wind.

A carefully chosen magnetic field between the above two cases can roughly reproduce the latitude-dependent wind required to form the peculiar periphery of Tycho’s SN remnant. This magnetic field may contain the tangled magnetic field in the accreted material obtained from the surface of the companion star, as well as contributions from the WD.

The study reveals the importance of magnetic field in the progenitor of Tycho’s SN. It also provides a new source of mass-loss, other than the mass-loss caused by hydrogen and helium flashes on the WD surface, which are often considered in binary evolution researches.

The mass-loss ratio is extremely large (above 90 percent) in the simulation, yet it is consistent with researches in accretion physics, and this outflow only lasts for a limited time before the SN explosion, so it does not handicap the mass accumulation of the WD much.

Reference: Li Xue, Cheng-Liang Jiao, Yuan Li, Three-dimensional simulations of accretion flow in the progenitor of Tycho’s supernova, Monthly Notices of the Royal Astronomical Society, , staa3696, https://academic.oup.com/mnras/article-abstract/501/1/664/6007743?redirectedFrom=fulltext https://doi.org/10.1093/mnras/staa3696

Provided by Chinese Academy of Sciences