bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of carbon interstitial-related defect levels by thermal injection of carbon into n-type 4H-SiC
Authors: Karsthof Robert , Etzelmüller Bathen Marianne , Kuznetsov Andrej , Vines Lasse
Published: January 2022

Electrical properties of point defects in 4H-SiC have been studied extensively, but those related to carbon interstitials (Ci) have remained elusive until now. Indeed, when introduced via ion irradiation or implantation, signatures related to Ci observed by deep level transient spectroscopy tend to overlap with those of other primary defects, making the direct identification of Ci-related levels difficult. Recent literature has suggested to assign the so-called M center, often found in as-irradiated 4H-SiC, to charge state transitions of the Ci defect in different configurations. In this work, we have introduced excess carbon into low-doped n-type 150 μm thick 4H-SiC epilayers by thermal annealing, with a pyrolyzed carbon cap on the sample surface acting as a carbon source. Because the layers exhibited initially low concentrations of carbon vacancies ([VC]=1011cm), this enabled us to study the case of complete VC annihilation and formation of defects due to excess carbon, i.e., carbon interstitials Ci and their higher-order complexes. We report on the occurrence of several new levels upon C injection, which are likely Ci-related. Their properties are different from those found for the M center, which point toward a different microscopic identity of the detected levels. This suggests the existence of a rich variety of Ci-related defects. The study will also help generating new insights into the microscopic process of VC annihilation during carbon injection processes.
Mechanism for the rare fluctuation that powers protein conformational change
Authors: Wu Shanshan , Ma Ao
Published: January 2022

Most functional processes of biomolecules are rare events. Key to a rare event is the rare fluctuation that enables the energy activation process that precedes and powers crossing of the activation barrier. However, the physical nature of this rare fluctuation and how it enables energy activation and subsequently barrier crossing are unknown. We developed a novel metric, the reaction capacity pC, that rigorously defines the beginning and parameterizes the progress of energy activation. This enabled us to identify the rare fluctuation as a special phase-space condition that is necessary and sufficient for initiating systematic energy flow from the non-reaction coordinates into the reaction coordinates. The energy activation of a prototype biomolecular isomerization reaction is dominated by kinetic energy transferring into and accumulating in the reaction coordinates, administered by inertial forces alone. This mechanism for energy activation is fundamentally different from the mechanism suggested by Kramers theory.
Numerical study of the effect of surface topography on atomization performance in geometrically sensitive areas of centrifugal nozzles
Authors: Shen Lixin , Qin La , Fang Gangyi , Xing Fei , Chan Shining
Published: January 2022

Integral three-dimensional printing of aeroengine fuel nozzles is an emerging trend. However, the large relative roughness of the internal flow paths created by this processing method is problematic. To study the influence of the rough surface morphology on atomization performance in geometrically sensitive areas of centrifugal nozzles, this paper describes numerical simulations of the atomization process of five nozzle models with rough orifice sections. The simulation framework considers a coupled internal and external flow in stages. The macroscopic morphology of the numerically calculated spray field is found to be consistent with experimental results, with maximum errors in the Sauter mean diameter, spray angle, and flow rate of just 8.7%, 3.7%, and 6.1%, respectively. The numerical results show that the nozzle's rough surface morphology in geometrically sensitive areas has a non-negligible impact on the liquid film velocity fluctuations, primary breakup, and secondary atomization characteristics. Indeed, the effect on primary breakup is large, with the maximum difference between the five rough-surface models reaching 22.9%. The effect on secondary atomization is small, with a maximum difference of just 5.7% except in the number of droplets, which has a maximum difference of 22.1%. Among the five rough-surface models, the atomization characteristics of the smooth model differ greatly from those of the real model, whereas a power-function model best reflects the real surface morphology. This study provides new ideas for nozzle performance prediction and optimization, and provides a reference for engineering applications of three-dimensional printed centrifugal nozzles.
Polarity reversal of resistance response to trace H2 gas in the air between asymmetrically shaped electrodes on rutile-TiO2 single crystal
Authors: Suzuki T. T. , Ohgaki T. , Adachi Y. , Sakaguchi I.
Published: January 2022

We investigated the resistance response to trace hydrogen gas in the air between the asymmetrically shaped point contact- (Pt tip) and plane contact- (Al thin-film) electrodes formed in-plane on a rutile TiO2 single crystal at 673 K. It was found that the polarity of the resistance response, that is, the increase or the decrease of the resistance by exposing to hydrogen, reverses depending on the bias voltage polarity. This reversal mechanism of the resistance response was analyzed from the electrical conduction properties and the depth profile of the oxygen tracer (18O) in the electric field-induced diffusion. The central mechanism is proposed to be the oxygen transfer reaction at the Pt/TiO2 interface, accompanied by the modulation of the positively charged-oxygen vacancy concentration, thus the resistance between the two terminals. It is also proposed that the proton hinders the transfer reaction at the interface; and hence, the resistance increases by exposing to hydrogen with biasing the positive voltage to the Pt tip electrode. The application of this reversal of the resistance response for separating hydrogen and ethanol in the trace gas sensing is discussed, which is quite limited for a conventional semiconductor gas sensor.
Ultra-slow and arrested density-fluctuations as precursor of spatial heterogeneity
Authors: Lira-Escobedo J. , Vélez-Cordero J. R. , Ramírez-González Pedro E.
Published: January 2022

Dynamical heterogeneities in glass-forming liquids subjected to cooling processes are studied by a theoretical framework based on the non-equilibrium self-consistent generalized Langevin equation theory. This theory predicts that slow cooling rates permit the relaxation to the equilibrium state distinguished by a homogeneous local density. In contrast, fast cooling rates provoke dynamically arrested density-fluctuations and the establishment of permanent spatial heterogeneities even in the presence of density gradients. We further show that the dynamics toward the arrested state has two steps: a truncated relaxation followed by a second relaxation of the diluted part of the system.
Noble–Abel/first-order virial equations of state for gas mixtures resulting from multiple condensed reactive materials combustion
Authors: Neron Loann , Saurel Richard
Published: January 2022

The Noble–Abel (NA) equation of state (EOS) is widely used in the interior ballistics of guns as well as rocket propulsion computations. Its simplicity and accuracy are key points for intensive computations with hyperbolic two-phase flow models considered in interior ballistics codes. An alternative formulation is examined in the present contribution through a first-order virial (VO1) equation of state. Appropriate methods for the determination of related parameters, such as specific gas constant, co-volume, and condensed material energy, for both formulations (NA and VO1) are presented. For this, a combination of closed bomb vessel experiments and thermochemical code computations is needed. An extended VO1 EOS with temperature-dependent specific heat is examined. Then, its extension to multiple reactive materials is addressed. Examples are examined for each formulation (NA and VO1) and comparisons are done with the Becker–Kistiakowsky–Wilson (BKW) EOS as reference. Several conclusions have emerged. First, a consideration of the specific heat temperature dependance in computations of the interior ballistics of guns appeared insignificant. Second, VO1 appeared to be more accurate than NA, particularly when gas density is beyond the range used for EOS parameter determination. Last, regarding mixtures of condensed reactive materials, producing burnt gas mixtures, NA again appeared to be less accurate than VO1. However, its formulation is explicit, while VO1 requires numerical solving of a non-linear equation, with consequences on computational cost.
Dynamic molecular conformational change leading to energy transfer in F8-5% BSP copolymer revealed by single-molecule spectroscopy
Authors: Yan Hao , Tseng Tzu-Wei , Omagari Shun , Hamilton Iain , Nakamura Tomonori , Vacha Martin , Kim Ji-Seon
Published: January 2022

Polyfluorene-based copolymers such as poly(9,9-dioctylfluorene)-alt-5% [bis-N,N′-(4-butylphenyl)-bis-N,N′-phenyl-1,4-phenylenediamine] (F8-5% BSP) are efficient blue-emitting polymers with various electronic phases: F8 blue-emitting glassy phase, F8 ordered more red-emitting β-phase, and F8/BSP charge transfer (CT) state. Polymer light-emitting device performance and color purity can be significantly improved by forming β-phase segments. However, the role of the β-phase on energy transfer (ET) among glassy F8, β-phase, and F8/BSP CT state is unclear. Herein, we identify dynamic molecular conformation-controlled ET from locally excited states to either the CT state or β-phase in light-emitting copolymers. By conducting single-molecule spectroscopy for single F8-5% BSP chains, we find inefficient intra-chain ET from glassy segments to the CT state, while efficient ET from the glassy to the β-phase. Spontaneous and reversible CT on–off emission is observed both in the presence and absence of the β-phase. The density functional theory calculations reveal the origin of the on-chain CT state and indicate this CT emission on–off switching behavior could be related to molecule torsional motion between BSP and F8 units. The population of the CT state by ET can be increased via through-space interaction between the F8 block and the BSP unit on a self-folded chain. Temperature-dependent single-molecule spectroscopy confirms such interaction showing a gradual increase in intensity of the CT emission with the temperature. Based on these observations, we propose the dynamic molecular motion-induced conformation change as the origin of the glassy-to-CT ET, and thermal energy may provide the activation for such a change to enhance the ET from glassy or β-phases to the CT state.
Effects of purifiers on the airborne transmission of droplets inside a bus
Authors: Yang Yafeng , Wang Yiping , Tian Linli , Su Chuqi , Chen Zhixin , Huang Yuanyi
Published: January 2022

During an airborne infectious disease outbreak, bus passengers can be easily infected by the dispersion of exhaled droplets from an infected passenger. Therefore, measures to control the transport of droplets are necessary, such as a mask or purifier. The current research examined aerosol transport in a bus with air-conditioning. To determine the dispersion path, deposition distribution, and droplet escape time, the computational fluid dynamics were used to predict the flow field and the dispersion of droplets considering the effects of droplet size, location of the infected person, and purifier type. In addition, based on the viability and the number of virus particles in a droplet, the total number of virus particles inhaled by passengers over a 4-h journey was obtained by the superposition method. The Wells–Riley equation was then used to assess the infection risk of the passengers in the bus cabin. The results showed that droplets with a size of 1–20 μm have essentially the same deposition characteristics, and the location of the infected passenger affects the distribution of droplets' transport and the effectiveness of a purifier in removing droplets. A purifier can effectively remove droplets from passengers' coughs and reduce the infection risk of passengers. The performance of the smaller purifiers is not as stable as that of the larger purifiers, and the performance is influenced by the airflow structure where the infected passenger is located.
Rapid radiation in a highly diverse marine environment
Authors: Hench Kosmas , Helmkampf Martin , McMillan W. Owen , Puebla Oscar
Published: January 2022

Significance

Adaptive radiation, the evolutionary process whereby a lineage diversifies over a short period of time, often occurs in geographically isolated or newly formed habitats where colonizing species encounter unoccupied niches and reduced selective pressures. Rapid radiations may also occur in diverse and complex environments, but these cases are less well documented. Here, we show that the hamlets, a group of Caribbean reef fishes, radiated within the last 10,000 generations in a burst of diversification that ranks among the fastest in fishes. Genomic analysis suggests that color pattern diversity is generated by different combinations of alleles at a few genes with large effect. Such a modular genomic architecture of diversification is emerging as a common denominator to a variety of radiations.
Surrogate gradients for analog neuromorphic computing
Authors: Cramer Benjamin , Billaudelle Sebastian , Kanya Simeon , Leibfried Aron , Grübl Andreas , Karasenko Vitali , Pehle Christian , Schreiber Korbinian , Stradmann Yannik , Weis Johannes , Schemmel Johannes , Zenke Friedemann
Published: January 2022

Significance

Neuromorphic systems aim to accomplish efficient computation in electronics by mirroring neurobiological principles. Taking advantage of neuromorphic technologies requires effective learning algorithms capable of instantiating high-performing neural networks, while also dealing with inevitable manufacturing variations of individual components, such as memristors or analog neurons. We present a learning framework resulting in bioinspired spiking neural networks with high performance, low inference latency, and sparse spike-coding schemes, which also self-corrects for device mismatch. We validate our approach on the BrainScaleS-2 analog spiking neuromorphic system, demonstrating state-of-the-art accuracy, low latency, and energy efficiency. Our work sketches a path for building powerful neuromorphic processors that take advantage of emerging analog technologies.
Genomic and transcriptomic analyses of the subterranean termite
Reticulitermes speratus
: Gene duplication facilitates social evolution
Authors: Shigenobu Shuji , Hayashi Yoshinobu , Watanabe Dai , Tokuda Gaku , Hojo Masaru Y. , Toga Kouhei , Saiki Ryota , Yaguchi Hajime , Masuoka Yudai , Suzuki Ryutaro , Suzuki Shogo , Kimura Moe , Matsunami Masatoshi , Sugime Yasuhiro , Oguchi Kohei , Niimi Teruyuki , Gotoh Hiroki , Hojo Masaru K. , Miyazaki Satoshi , Toyoda Atsushi , Miura Toru , Maekawa Kiyoto
Published: January 2022

Significance

Gene duplication is a major source of evolutionary innovation and is associated with the increases in biological complexity and adaptive radiation. Termites are model social organisms characterized by a sophisticated caste system. We analyzed the genome of the Japanese subterranean termite, an ecologically and economically important insect acting as a destructive pest. The analyses revealed the significance of gene duplication in social evolution. Gene duplication associated with caste-biased gene expression was prevalent in the termite genome. Many of the duplicated genes were related to social functions, such as chemical communication, social immunity, and defense, and they were often expressed in caste-specific organs. We propose that gene duplication facilitates social evolution through regulatory diversification leading to caste-biased expression and functional specialization.
Extra-pair paternity explains cooperation in a bird species
Authors: Krams Indrikis A. , Mennerat Adèle , Krama Tatjana , Krams Ronalds , Jõers Priit , Elferts Didzis , Luoto Severi , Rantala Markus J. , Eliassen Sigrunn
Published: January 2022

Significance

In many monogamous species, a substantial proportion of offspring is sired by other males than the one providing care at the nest. Although females often solicit extra-pair mating, the benefits of extra-pair copulations to females are not fully understood. In this study on pied flycatchers, we tested whether extra-pair paternity in neighboring nests may have affected the likelihood that males helped defend extra-pair offspring against predators. We found that extra-pair sires were more often engaged and invested more heavily in cooperative predator defense than males without extra-pair offspring. For female flycatchers, extra-pair mating may thus be an adaptive strategy for enhancing offspring survival and breeding success.
Rad54 and Rdh54 prevent Srs2-mediated disruption of Rad51 presynaptic filaments
Authors: Meir Aviv , Crickard J. Brooks , Kwon Youngho , Sung Patrick , Greene Eric C.
Published: January 2022

Significance

Homologous DNA recombination is an essential pathway necessary for the repair of double-stranded DNA breaks. Defects in this pathway are associated with hereditary breast cancer, ovarian cancer, and cancer-prone syndromes. Although essential, too much recombination is also bad and can lead to genetic mutations. Thus, cells have evolved “antirecombinase” enzymes that can actively dismantle recombination intermediates to prevent excessive recombination. However, our current understanding of how antirecombinases are themselves regulated remains very limited. Here, we study the antirecombinase Srs2 and its regulation by the recombination accessory factors Rad54 and Rdh54. Our data suggest that Rad54 and Rdh54 act synergistically to function as key regulators of Srs2, thus serving as “licensing factors” that enable timely progression of DNA repair.
Why sequence all eukaryotes?
Authors: Blaxter Mark , Archibald John M. , Childers Anna K. , Coddington Jonathan A. , Crandall Keith A. , Di Palma Federica , Durbin Richard , Edwards Scott V. , Graves Jennifer A. M. , Hackett Kevin J. , Hall Neil , Jarvis Erich D. , Johnson Rebecca N. , Karlsson Elinor K. , Kress W. John , Kuraku Shigehiro , Lawniczak Mara K. N. , Lindblad-Toh Kerstin , Lopez Jose V. , Moran Nancy A. , Robinson Gene E. , Ryder Oliver A. , Shapiro Beth , Soltis Pamela S. , Warnow Tandy , Zhang Guojie , Lewin Harris A.
Published: January 2022

Life on Earth has evolved from initial simplicity to the astounding complexity we experience today. Bacteria and archaea have largely excelled in metabolic diversification, but eukaryotes additionally display abundant morphological innovation. How have these innovations come about and what constraints are there on the origins of novelty and the continuing maintenance of biodiversity on Earth? The history of life and the code for the working parts of cells and systems are written in the genome. The Earth BioGenome Project has proposed that the genomes of all extant, named eukaryotes—about 2 million species—should be sequenced to high quality to produce a digital library of life on Earth, beginning with strategic phylogenetic, ecological, and high-impact priorities. Here we discuss why we should sequence all eukaryotic species, not just a representative few scattered across the many branches of the tree of life. We suggest that many questions of evolutionary and ecological significance will only be addressable when whole-genome data representing divergences at all of the branchings in the tree of life or all species in natural ecosystems are available. We envisage that a genomic tree of life will foster understanding of the ongoing processes of speciation, adaptation, and organismal dependencies within entire ecosystems. These explorations will resolve long-standing problems in phylogenetics, evolution, ecology, conservation, agriculture, bioindustry, and medicine.
Standards recommendations for the Earth BioGenome Project
Authors: Lawniczak Mara K. N. , Durbin Richard , Flicek Paul , Lindblad-Toh Kerstin , Wei Xiaofeng , Archibald John M. , Baker William J. , Belov Katherine , Blaxter Mark L. , Marques Bonet Tomas , Childers Anna K. , Coddington Jonathan A. , Crandall Keith A. , Crawford Andrew J. , Davey Robert P. , Di Palma Federica , Fang Qi , Haerty Wilfried , Hall Neil , Hoff Katharina J. , Howe Kerstin , Jarvis Erich D. , Johnson Warren E. , Johnson Rebecca N. , Kersey Paul J. , Liu Xin , Lopez Jose Victor , Myers Eugene W. , Pettersson Olga Vinnere , Phillippy Adam M. , Poelchau Monica F. , Pruitt Kim D. , Rhie Arang , Castilla-Rubio Juan Carlos , Sahu Sunil Kumar , Salmon Nicholas A. , Soltis Pamela S. , Swarbreck David , Thibaud-Nissen Françoise , Wang Sibo , Wegrzyn Jill L. , Zhang Guojie , Zhang He , Lewin Harris A. , Richards Stephen
Published: January 2022

A global international initiative, such as the Earth BioGenome Project (EBP), requires both agreement and coordination on standards to ensure that the collective effort generates rapid progress toward its goals. To this end, the EBP initiated five technical standards committees comprising volunteer members from the global genomics scientific community: Sample Collection and Processing, Sequencing and Assembly, Annotation, Analysis, and IT and Informatics. The current versions of the resulting standards documents are available on the EBP website, with the recognition that opportunities, technologies, and challenges may improve or change in the future, requiring flexibility for the EBP to meet its goals. Here, we describe some highlights from the proposed standards, and areas where additional challenges will need to be met.
EBP-Colombia and the bioeconomy: Genomics in the service of biodiversity conservation and sustainable development
Authors: Huddart Joseph E. A. , Crawford Andrew J. , Luna-Tapia Arturo L. , Restrepo Silvia , Di Palma Federica
Published: January 2022

The 2016 Peace Agreement has increased access to Colombia’s unique ecosystems, which remain understudied and increasingly under threat. The Colombian government has recently announced its National Bioeconomic Strategy (NBS), founded on the sustainable characterization, management, and conservation of the nation's biodiversity as a means to achieve sustainability and peace. Molecular tools will accelerate such endeavors, but capacity remains limited in Colombia. The Earth Biogenome Project's (EBP) objective is to characterize the genomes of all eukaryotic life on Earth through networks of partner institutions focused on sequencing either specific taxa or eukaryotic communities at regional or national scales. Colombia’s immense biodiversity and emerging network of stakeholders have inspired the creation of the national partnership “EBP-Colombia.” Here, we discuss how this Colombian-driven collaboration between government, academia, and the private sector is integrating research with sustainable, environmentally focused strategies to develop Colombia’s postconflict bioeconomy and conserve biological and cultural diversity. EBP-Colombia will accelerate the uptake of technology and promote partnership and exchange of knowledge among Colombian stakeholders and the EBP’s global network of experts; assist with conservation strategies to preserve Colombia’s vast biological wealth; and promote innovative approaches among public and private institutions in sectors such as agriculture, tourism, recycling, and medicine. EBP-Colombia can thus support Colombia’s NBS with the objective of sustainable and inclusive development to address the many social, environmental, and economic challenges, including conflict, inequality, poverty, and low agricultural productivity, and so, offer an alternative model for economic development that similarly placed countries can adopt.
Threatened Species Initiative: Empowering conservation action using genomic resources
Authors: Hogg Carolyn J. , Ottewell Kym , Latch Peter , Rossetto Maurizio , Biggs James , Gilbert Andrew , Richmond Sarah , Belov Katherine
Published: January 2022

Globally, 15,521 animal species are listed as threatened by the International Union for the Conservation of Nature, and of these less than 3% have genomic resources that can inform conservation management. To combat this, global genome initiatives are developing genomic resources, yet production of a reference genome alone does not conserve a species. The reference genome allows us to develop a suite of tools to understand both genome-wide and functional diversity within and between species. Conservation practitioners can use these tools to inform their decision-making. But, at present there is an implementation gap between the release of genome information and the use of genomic data in applied conservation by conservation practitioners. In May 2020, we launched the Threatened Species Initiative and brought a consortium of genome biologists, population biologists, bioinformaticians, population geneticists, and ecologists together with conservation agencies across Australia, including government, zoos, and nongovernment organizations. Our objective is to create a foundation of genomic data to advance our understanding of key Australian threatened species, and ultimately empower conservation practitioners to access and apply genomic data to their decision-making processes through a web-based portal. Currently, we are developing genomic resources for 61 threatened species from a range of taxa, across Australia, with more than 130 collaborators from government, academia, and conservation organizations. Developed in direct consultation with government threatened-species managers and other conservation practitioners, herein we present our framework for meeting their needs and our systematic approach to integrating genomics into threatened species recovery.
Darwinian genomics and diversity in the tree of life
Authors: Stephan Taylorlyn , Burgess Shawn M. , Cheng Hans , Danko Charles G. , Gill Clare A. , Jarvis Erich D. , Koepfli Klaus-Peter , Koltes James E. , Lyons Eric , Ronald Pamela , Ryder Oliver A. , Schriml Lynn M. , Soltis Pamela , VandeWoude Sue , Zhou Huaijun , Ostrander Elaine A. , Karlsson Elinor K.
Published: January 2022

Genomics encompasses the entire tree of life, both extinct and extant, and the evolutionary processes that shape this diversity. To date, genomic research has focused on humans, a small number of agricultural species, and established laboratory models. Fewer than 18,000 of ∼2,000,000 eukaryotic species (<1%) have a representative genome sequence in GenBank, and only a fraction of these have ancillary information on genome structure, genetic variation, gene expression, epigenetic modifications, and population diversity. This imbalance reflects a perception that human studies are paramount in disease research. Yet understanding how genomes work, and how genetic variation shapes phenotypes, requires a broad view that embraces the vast diversity of life. We have the technology to collect massive and exquisitely detailed datasets about the world, but expertise is siloed into distinct fields. A new approach, integrating comparative genomics with cell and evolutionary biology, ecology, archaeology, anthropology, and conservation biology, is essential for understanding and protecting ourselves and our world. Here, we describe potential for scientific discovery when comparative genomics works in close collaboration with a broad range of fields as well as the technical, scientific, and social constraints that must be addressed.
Balancing openness with Indigenous data sovereignty: An opportunity to leave no one behind in the journey to sequence all of life
Authors: Mc Cartney Ann M. , Anderson Jane , Liggins Libby , Hudson Maui L. , Anderson Matthew Z. , TeAika Ben , Geary Janis , Cook-Deegan Robert , Patel Hardip R. , Phillippy Adam M.
Published: January 2022

The field of genomics has benefited greatly from its “openness” approach to data sharing. However, with the increasing volume of sequence information being created and stored and the growing number of international genomics efforts, the equity of openness is under question. The United Nations Convention of Biodiversity aims to develop and adopt a standard policy on access and benefit-sharing for sequence information across signatory parties. This standardization will have profound implications on genomics research, requiring a new definition of open data sharing. The redefinition of openness is not unwarranted, as its limitations have unintentionally introduced barriers of engagement to some, including Indigenous Peoples. This commentary provides an insight into the key challenges of openness faced by the researchers who aspire to protect and conserve global biodiversity, including Indigenous flora and fauna, and presents immediate, practical solutions that, if implemented, will equip the genomics community with both the diversity and inclusivity required to respectfully protect global biodiversity.
Evidence of magnetism-induced topological protection in the axion insulator candidate EuSn
2
P
2
Authors: Pierantozzi Gian Marco , De Vita Alessandro , Bigi Chiara , Gui Xin , Tien Hung-Ju , Mondal Debashis , Mazzola Federico , Fujii Jun , Vobornik Ivana , Vinai Giovanni , Sala Alessandro , Africh Cristina , Lee Tien-Lin , Rossi Giorgio , Chang Tay-Rong , Xie Weiwei , Cava Robert J. , Panaccione Giancarlo
Published: January 2022

Significance

Understanding the mutual influence between magnetic and topological properties in a solid system is a fundamental challenge for quantum materials research. The so-called axion insulator is one such case, with exotic properties related to the magnetoelectric effect. In this work, by combining chemical and magnetic-state sensitive electron and X-ray spectroscopies with first-principle calculations we reveal that EuSn
2
P
2
holds the characteristics of an axion insulator and displays “hidden” electronic properties arising from its layer-dependent ferromagnetic character. As a function of the termination, we observe specific electronic states, holding a spin arrangement representative of a topological insulator. Furthermore, the direction of magnetization enables topological protection, a key property related to axion-based physics.
Lipid membranes modulate the activity of RNA through sequence-dependent interactions
Authors: Czerniak Tomasz , Saenz James P.
Published: January 2022

Significance

Lipids, which are essential for life and one of the most ancient biomolecules, can spontaneously self-assemble to form membranous bilayers, theoretically providing a surface that can serve to concentrate, protect, and regulate RNAs. Here, we show that direct RNA–lipid interactions can modulate ribozyme activity in a lipid-dependent manner. We further demonstrate that RNA–lipid binding is influenced by nucleotide content and base pairing of RNAs. This yields an essential framework for engineering RNA–lipid systems that can be regulated based on sequence specificity and introduces a mechanism for riboregulation in cellular, synthetic, and prebiotic systems.
Atomic structure of Lanreotide nanotubes revealed by cryo-EM
Authors: Pieri Laura , Wang Fengbin , Arteni Ana-Andreea , Vos Matthijn , Winter Jean-Marie , Le Du Marie-Hélène , Artzner Franck , Gobeaux Frédéric , Legrand Pierre , Boulard Yves , Bressanelli Stéphane , Egelman Edward H. , Paternostre Maité
Published: January 2022

Significance

The spectacular developments in cryoelectron microscopy involving new cameras, new microscopes, and new software make it possible today to routinely determine the atomic structures of a large range of molecular assemblies. This has allowed us to solve the atomic structure of nanotubes formed from a peptide, Lanreotide. Its gel, Somatuline, is used as a synthetic growth hormone inhibitor in the treatment of both acromegaly and cancers. The self-assembled nanotube results in a slow release form of the peptide, important pharmacologically. The nanotube structure shows an unexpected complexity and highlights the still unpredictable chemical and physicochemical determinants driving peptide self-assembly.
Documentation in specialised contexts
Authors: Mar Sánchez Ramos María del
Published: January 2022

Existing training programmes in the field of public service interpreting and translation (PSIT) do not to focus on how best to develop students’ lexical competence and corpora-based search skills. This paper reports the design, implementation and evaluation of a novel corpus-based module intended to develop Spanish postgraduate PSIT students’ lexical competence and search strategies. Adopting a mixed-methods quasi-experimental design, we administered a pre- and post-test to both an experimental group and a control group to collect quantitative data and determine whether the corpus-based module contributes to improving participants’ lexical competence and search strategies. Semi-structured focus groups were conducted to collect qualitative data, which were thematically analysed. The findings indicate that a corpus-based methodology significantly improves PSIT students’ skills in these areas, leading to the conclusion that such an approach should be adopted more widely in PSIT pedagogy.
Correlation of stacking fault energy with deformation mechanism in Cu–(2, 20)Zn alloys
Authors: Wei Huan , Jia Jianwen , Du Huayun , Zhou Caizhi , Wei Yinghui , Hou Lifeng
Published: January 2022

Copper–zinc alloys with different zinc contents contain different stacking fault energies (SFE). The influence of SFE on the deformation mechanism during surface mechanical attrition treatment was studied in this work. Research results indicate that the deformation mechanism directly correlated with the SFE in Cu–Zn alloys. Deformation twinning plays a paramount role during original deformation in Cu–20Zn (19 mJ/m2). However, for Cu–2Zn alloy with low-medium SFE (38 mJ/m2), the deformation mechanism is dominated by the dislocation slipping. Microbands are the predominant microstructural features in large strain and high strain rate regions for both Cu–Zn alloys in the present study. They are likely to be formed by the splitting of the high-density dislocation walls.
The Lorentz group and the Kronecker product of matrices
Authors: Larsson Jonas , Larsson Karl
Published: January 2022

The group

S
L

(

2
,
C

)

of all complex 2 × 2 matrices with determinant one is closely related to the group

L

+

↑

of real 4 × 4 matrices representing the restricted Lorentz transformations. This relation, sometimes called the spinor map, is of fundamental importance in relativistic quantum mechanics and has applications also in general relativity. In this paper we show how the spinor map may be expressed in terms of pure matrix algebra by including the Kronecker product between matrices in the formalism. The so-obtained formula for the spinor map may be manipulated by matrix algebra and used in the study of Lorentz transformations.
High-temperature-resistant frequency selective metasurface with low-frequency diffusion and high-frequency transmission
Authors: Liang Cheng-Peng , Zhang Xiao , Fan Long-Zhen , Zhou Ming-Xing , Leung ShuWai , Wang Ya-Nan , Li Fei-Fei , Poo Yin
Published: January 2022

This paper presents a high-temperature-resistant frequency selective metasurface with wide-band low-backward scattering at lower frequencies and wide-band efficient transmission at higher frequencies. The metasurface consists of three functional layers: lagging made of a low-loss insulation tile, a diffusive metasurface and a frequency-selective surface (FSS). The diffusion metasurface is comprised of various specially arranged square rings, where meander lines are integrated, ensuring transmission at higher frequencies. Seperated by a piece of honeycomb paper, a triple-layer coupled-resonator spatial filter FSS is placed below the diffusive metasurface. Based on the phase cancellation technique and dual-resonance transmission, a 10 dB reduction of radar cross section is achieved from 2.45 GHz to 11.55 GHz and a wide-band transmission lower than 1 dB is obtained in 17.33–19.08 GHz. In addition, a standard thermal test and subsequent electromagnetic test show that our sample maintains good performance after being heated at 500 °C for 5 s. This work opens a new route for designing frequency-selective metasurfaces with high temperature resistance.
Study on the characteristics of a photonic crystal sensor with rectangular lattice based on bound states in the continuum
Authors: Wang Zhan , Xue Qi , Zhao SaiLi , Zhang XiaoRong , Liu HuiMin , Sun XiaoHong
Published: January 2022

In this paper, a sensor model of a photonic crystal with a rectangular lattice is proposed and its sensing characteristics based on bound states in the continuum are studied using the finite element method. Using the different resonances of the rectangular lattice in two axes, the resonance line-width can be adjusted by the polarization direction of incident light. This structure can achieve a sensitivity of 148 nm RIU−1 and the figure of merit above 821 RIU−1, which shows a great potential in high-quality sensors, filter, laser line-width modulation as well as measurement of angle and angular velocity.
Majorana neutrinos, exceptional Jordan algebra, and mass ratios for charged fermions
Authors: Bhatt Vivan , Mondal Rajrupa , Vaibhav Vatsalya , Singh Tejinder P
Published: January 2022

We provide theoretical evidence that the neutrino is a Majorana fermion. This evidence comes from assuming that the standard model and beyond-standard-model physics can be described through division algebras, coupled to quantum dynamics. We use the division algebras scheme to derive mass ratios for the standard model charged fermions of three generations. The predicted ratios agree well with the observed values if the neutrino is assumed to be Majorana. However, the theoretically calculated ratios completely disagree with known values if the neutrino is taken to be a Dirac particle. Towards the end of the article we discuss prospects for unification of the standard model with gravitation if the assumed symmetry group of the theory is E
6, and if it is assumed that space-time is an 8D octonionic space-time, with 4D Minkowski space-time being an emergent approximation. Remarkably, we find evidence that the precursor of classical gravitation, described by the symmetry SU(3)grav × SU(2)R × U(1)grav is the right-handed counterpart of the standard model SU(3)color × SU(2)L × U(1)
Y
. This provides the theoretical justification for the mass-ratios analysis based on the eigenvalues of the exceptional Jordan algebra.
Spin accumulation and spin Hall effect in a two-layer system with a thin ferromagnetic layer
Authors: Zhuravlev Mikhail , Alexandrov Artem , Vedyayev Anatoly
Published: January 2022

Spin accumulation and spin current are phenomena that enhance the functionality of the devices operating with charge and spin. We calculated them for the system consisting of a ferroelectric barrier and a thin ferromagnetic layer when the current flows parallel to the interface. We assume Dresselhaus and Rashba spin–orbit coupling linear in electron wave number. We demonstrate that spin accumulation and spin current can be manipulated by changing the direction of the magnetization of the FM layer with respect to the crystallographic axes of the ferroelectric barrier.
A novel inductive angular displacement sensor based on time-grating
Authors: Sun Shizheng , Lv Ze , Han Yu , He Zeyin , Zhang Junming
Published: January 2022

The paper proposes a novel inductive angular displacement sensor to measure large-diameter hollow rotating mechanical components in large science facilities. The sensor design includes a stator, a rotor with two layers of windings. The stator is fabricated according to the dimension of the rotor, which is the large-diameter hollow rotary mechanical components. Based on the principle of electromagnetic induction, the theoretical model of the proposed sensor is acquired by mathematical equations in detail. The proposed sensor design ensures integration of the large-diameter hollow rotating mechanical components with the stator, and solves the problem that the sensors cannot be coaxially installed in the closed-loop control process of large mechanical rotating parts. The performance of the sensor is evaluated by tests of the prototype sensor fabricated by printed circuit board technology, which manifests the effectiveness of the proposed sensor. The results demonstrate the value of original dynamic relative error is ±97.6″ over 0°–360° range, and the measurement error mainly includes first-order and second-order harmonic components. Therefore, the original errors are reduced by optimizing the angular displacement algorithm of the sensor, optimized results demonstrate the final relative accuracy of the sensor is ±3.5″ over the 0°–360° measurement range.
Detection of trace volatile organic compounds in spiked breath samples: a leap towards breathomics
Authors: Ray Bishakha , Parmar Saurabh , Vijayan Varsha , Vishwakarma Satyendra , Datar Suwarna
Published: January 2022

Breathomics is the future of non-invasive point-of-care devices. The field of breathomics can be split into the isolation of disease-specific volatile organic compounds (VOCs) and their detection. In the present work, an array of five quartz tuning fork (QTF)-based sensors modified by polymer with nanomaterial additive has been utilized. The array has been used to detect samples of human breath spiked with ∼0.5 ppm of known VOCs namely, acetone, acetaldehyde, octane, decane, ethanol, methanol, styrene, propylbenzene, cyclohexanone, butanediol, and isopropyl alcohol which are bio-markers for certain diseases. Polystyrene was used as the base polymer and it was functionalized with 4 different fillers namely, silver nanoparticles-reduced graphene oxide composite, titanium dioxide nanoparticles, zinc ferrite nanoparticles-reduced graphene oxide composite, and cellulose acetate. Each of these fillers enhanced the selectivity of a particular sensor towards a certain VOC compared to the pristine polystyrene-modified sensor. Their interaction with the VOCs in changing the mechanical properties of polymer giving rise to change in the resonant frequency of QTF is used as sensor response for detection. The interaction of functionalized polymers with VOCs was analyzed by FTIR and UV–vis spectroscopy. The collective sensor response of five sensors is used to identify VOCs using an ensemble classifier with 92.8% accuracy of prediction. The accuracy of prediction improved to 96% when isopropyl alcohol, ethanol, and methanol were considered as one class.
A modified model to estimate the screening current-induced magnetic field of a REBCO magnet
Authors: Tang Yunkai , Liu Donghui , Li Dongke , Yong Huadong , Zhou Youhe
Published: January 2022

Experiments have shown that the actual value of the magnetic field in a magnet wound by rare-earth (RE) Ba2Cu3O7−x
tape during operation is less than its design value due to the effect of the screening current-induced magnetic field (SCMF). Several simulation methods have been used to calculate the SCMF. In this paper, a modified model is proposed to estimate the SCMF of a magnet based on the previous simple model. The inductance correction and field-dependent critical current density are considered in the modified model. Two parameters, the reversal and Nagaoka coefficients, are introduced in the model. The former is used to track the location of the minimum SCMF value in the charging process and the latter is applied to correct the induction of the magnet. The numerical results indicate that the SCMF estimated by the modified model is in agreement with those from experiments and the finite element method. Moreover, the effects of electromagnetic and geometrical parameters on the reversal and Nagaoka coefficients are also investigated. Finally, the model is extended to estimate the SCMF of a no-insulation magnet.
Magnetosonic waves in ion trapped semiconductor chip plasma with effect of exchange correlation potential and relativistic degeneracy
Authors: Safdar A , Mushtaq A , Usman S , Aman-ur-Rehman
Published: January 2022

The generalized dispersion relation for the propagation of magnetohydrodynamic (MHD) waves in Cd+ ion trapped semiconductor electron-hole-ion plasmas is studied with effect of quantum corrections. The important ingredients of these corrections occurred due to Bohm potential, relativistic degeneracy, exchange-correlation potential and spin magnetization and have significant impact on the dispersion properties of perpendicular and oblique modes of MHD wave. The derived results are numerically analyzed by using the numerical parameters of GaAs, GaSb, GaN, and InP semiconductors plasmas. From the numerical analysis it is observed that for higher number density, the phase speed of magnetosonic wave is larger for the InP semiconductor, while for low number density plasma region, it gives lower values for GaAs semiconductor. Similarly the phase speed of magnetosonic wave for GaAs decreases with applied magnetic field for different regime of number density. Due to exchange-correlation potential it is found that the frequencies of magnetosonic waves are blue-shifted means that it has magnified the phase speed. It is also shown that frequency of oblique MHD wave for GaAs semiconductor plasmas increases (decreases) with number density of electrons (holes). The relativistic degeneracy term (γ) for given number density is numerically calculated (1.00011 ∼ 1.0058) for all the above-mentioned semiconductors and it is observed that due to its mild numerical value it has not significant impact on graphical manipulation. The Alfven speed for above compound semiconductors with B
0 ≤ 104
G is also calculated which are in the permissible range of order 104 cm/s to 107 cm/s. The results are helpful to understand the energy transport in semiconductor plasma in the presence of magnetic field.
Development of an analytical model of work function modulated GAA MOSFET for electrostatic performance analysis
Authors: Bhol Krutideepa , Nanda Umakanta , Jena Biswajit , Tayal Shubham , Biswal Sudhansu M
Published: January 2022

This paper describes a continuous and almost linearly modulated work-function adjustment between 4.8–4.2eV using Hf-Mo binary alloy. The work-function modulated (WM) metal gate is applied to a gate all around MOSFET (GAA) for better electrostatic control. The threshold voltage is tuned by linearly modulating the gate metal work function. The threshold voltage extracted for dual-GAA MOSFET is initially 0.705 V. However, introducing work-function modulation, the threshold voltage is shifted to 0.620 V for WMGAA and 0.632 V for dual-WMGAA MOSFET. The simulation results validate the benefits of using work-function modulated metal gate in place of normal metal gate in terms of electron mobility, threshold voltage (Vth), and drain current (Id). An improved device performance with reduced short channel effect shows the capability of this device for various circuit applications.
Synthesis of Ti3C2Tx MXene from the Ti3AlC2 MAX phase with enhanced optical and morphological properties by using ammonia solution with the in-situ HF forming method
Authors: Ashok Anamika , Saseendran Swathy B , Asha A S
Published: January 2022

Liquid phase exfoliation of Ti3C2Tx MXene using LiF/HCl mix, forming HF in situ, has been modified by the addition of NH4OH. The base assisted dilution and extraction of MXene enables a quick control over pH and improves the structural, morphological and optical properties of the compound. The formation of a buffer compound NH4F, reduces the oxidation on the surface of MXene and etches off the residual MAX phase, by attacking Al. The structural features of the prepared NH4OH added Ti3C2Tx MXene are remarkably better than the HF etched samples, with the characteristic MXene peak in XRD being emphasized in the former. The addition of ammonia solution improves the milder in situ HF etching technique, by giving the characteristic open accordion structure to the compound, making the compound easy to delaminate and more stable against oxidation in ambient atmosphere.