bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovation in mining: what are the challenges and opportunities along the value chain for Latin American suppliers?
Authors: Calzada Olvera Beatriz
Published: February 2021

The mining industry, considered a traditional and conservative industry with respect to innovation, finds itself at a turning point due to the increasingly complex challenges, such as declining ore grades. These challenges have created an imperative to innovate. Parallel to the above, several digital innovations are being implemented in many mining operations across the globe. Not only do these provide solutions to the existing problems but also radically transform mining processes, increasing efficiency, profitability, and the ability to comply with stricter regulations. The incorporation of mature and incipient technologies into the mining industry has opened up many opportunities for long-established firms as well as knowledge-based start-ups. This includes potential suppliers in countries where mining accounts for a significant share of the GDP but the development of productive linkages remains suboptimal, as in Latin American countries. While in recent years, some suppliers in Latin America have made important contributions to increasing innovation in the mining industry, most suppliers in the region have not been able to do so. This paper provides an overview of the innovation paradigm of the mining sector from a global perspective, i.e., how innovation processes take place in countries with a long-established technological leadership in the mining sector, such as Australia and Canada. Given the importance of suppliers in this process, a special attention is paid to innovation in various stages of the supply chain. This is in order to provide a departure point for identifying windows of opportunity for equipment and service suppliers in Latin America.
Data-driven model order reduction for granular media
Authors: Wallin Erik , Servin Martin
Published: February 2021

We investigate the use of reduced-order modelling to run discrete element simulations at higher speeds. Taking a data-driven approach, we run many offline simulations in advance and train a model to predict the velocity field from the mass distribution and system control signals. Rapid model inference of particle velocities replaces the intense process of computing contact forces and velocity updates. In coupled DEM and multibody system simulation, the predictor model can be trained to output the interfacial reaction forces as well. An adaptive model order reduction technique is investigated, decomposing the media in domains of solid, liquid, and gaseous state. The model reduction is applied to solid and liquid domains where the particle motion is strongly correlated with the mean flow, while resolved DEM is used for gaseous domains. Using a ridge regression predictor, the performance is tested on simulations of a pile discharge and bulldozing. The measured accuracy is about 90% and 65%, respectively, and the speed-up range between 10 and 60.
Effective thermal conductivity in granular media with devolatilization: the Lattice Boltzmann modelling
Authors: Grucelski Arkadiusz
Published: February 2021

Flow thermomechanics in reactive porous media is of importance in industry including the thermal processing of fossil fuel (coking understood as a slow pyrolysis) involving devolatilisation. On the way to provide a detailed description of the process, a multi-scale approach was chosen to estimate effective transport coefficients. For this case the Lattice Boltzmann method (LBM) was used due to its advantages to accurately model multi-physics and chemistry in a random geometry of granular media. After account for earlier studies, the paper presents description of the model with improved boundary conditions and a benchmark case. Results from meso-scale LBM calculations are presented and discussed regarding the spatial resolution and the choice of relaxation parameter along its influence on the accuracy compared with empirical formulae. Regarding the estimation of effective thermal conductivity coefficient it is shown that occurrence of devolatilization has a crucial effect by reducing heat transfer. Some quantitative results characterise the propagation of thermal front; also presented is the evolution of effective thermal conductivity. The work is a step forward towards a physically sound simulation of thermal processing of fossil fuel.
Accept and apply diversity? An exploratory study of the attitudes towards diversity of students of STEM subjects
Authors: Genkova Petia , Schreiber Henrik
Published: February 2021

German universities are obligated to guarantee a fair learning environment for students with diverse features. They also must prepare students for a highly diverse working environment. This means to develop awareness for diversity and to train intercultural competence. The present study takes an exploratory look at the extent to which diversity awareness is established among science, technology, engineering, and mathematics (STEM) students and which barriers for the academic success students with a migration background perceive. To counteract discrepancies between the current state and the need for diversity awareness at universities, it identifies areas with room for improvement regarding the dealing with cultural diversity. Structured interviews with 31 STEM students were carried out and analyzed using qualitative content analysis. The interviews revealed differences in the awareness of diversity between students with and without a migration background. Results showed that there are barriers for STEM students with migration backgrounds which potentially reduce their academic success. Those barriers result from a lack of acceptance of cultural diversity and insufficient social integration and were especially apparent in insufficient language skills, orientation difficulties, and a lower degree of social integration. On the other hand, there is a need for both students with and without a migration background to promote competence and raise awareness for diversity. Furthermore, the role of social support as a resource became apparent.
Circular Agreements—Exploring the Role of Agreements and Deals as a Political Tool for a Circular Economy
Authors: Johansson Nils
Published: February 2021

A problem for a circular economy, embedded in its policies, tools, technologies and models, is that it is driven by the interests and needs of producers, rather than customers and users. This opinion paper focuses on an alternative form of governance—agreements, which thanks to their bargaining approach brings actors from across the value chain into the policy process. The purpose of this opinion paper is to uncover and analyse the potential of such agreements for a circular economy. Circular agreements aim at increasing the circulation of materials and are an emerging form of political governance within the EU. These agreements have different names, involve different actors and govern in different ways. However, circular agreements seem to work when other types of regulations fail to establish circulation. These agreements bring actors together and offer a platform for negotiating how advantages and disadvantages can be redistributed between actors in a way that is more suitable for a circular economy. However, circular agreements are dependent on other policy instruments to work and can generate a free-rider problem with uninvolved actors. The agreements may also become too detailed and long term, which leads to problem shifting and lock-ins, respectively.
Qui sont les élèves à besoins éducatifs particuliers?
Authors: Noël Isabelle
Published: February 2021

Dans cet article, nous questionnons la notion de besoins éducatifs particuliers, utilisée actuellement en Suisse, en revenant sur ses fondements historiques et en développant les principaux enjeux et problématiques qu’elle soulève. Nous présentons ensuite les résultats d’une recherche compréhensive visant à décrire les facteurs qui incitent les enseignants à signaler un élève pour une mesure d’aide renforcée de pédagogie spécialisée (MAR) durant la scolarité obligatoire dans un canton suisse. À partir de l’analyse de contenu des fiches de signalement pour une MAR produites durant l’année scolaire 2016-2017, ainsi que d’entretiens compréhensifs menés auprès d’enseignants titulaires, nous montrons en quoi il y a une part d’aléatoire dans le fait d’être désigné pour une MAR et discutons de façon critique le rôle de l’institution scolaire et de ses acteurs dans ce processus.
Bad Habits: Habit, Idleness, and Race in Hegel
Authors: Zambrana Rocío
Published: February 2021

Recent discussions of Hegel's conception of second nature, specifically focused on Hegel's notion of habit (Gewohnheit), have greatly advanced our understanding of Hegel's views on embodied normativity. This essay examines Hegel's account of embodied normativity in relation to his assessment of good and bad habits. Engaging Hegel's account of the rabble (Pöbel) in thePhilosophy of Rightand Frank Ruda's assessment of Hegel's rabble, this essay traces the relation between ethicality, idleness and race in Hegel. In being a figure of refusal in its affirmation of idleness, the rabble disallows the progressive revision of the project of modernity central to Hegel's philosophy. Hegel's discussion of the rabble is thus key to assessing the production of race within Hegel's notion of ethical life.
The multilevel effectiveness of entrepreneurial leadership: A meta-analysis
Authors: Lin Qin , Yi Lingfeng
Published: February 2021

The effectiveness of entrepreneurial leadership (EL) at different levels has been widely recognized by scholars who have carried out substantial exploration; however, the empirical studies on the effectiveness of EL are scattered and their results are mixed. This study aims to organize these findings, advance knowledge about the multilevel effectiveness of EL and clarify the heterogeneity in the relationship between EL and effectiveness outcomes. Based on a systematic review of the extant literature and the construction of an integrated framework, this study examines the influence of EL on effectiveness outcomes at multiple levels and the moderators of this relationship through meta-analysis of 35 empirical studies including 35 independent samples. The results show that EL can improve effectiveness outcomes at different levels of organization, team and individual; cultural context obviously moderates this relationship, whereas the moderating effects of enterprise type and EL measure are all not significant. This study helps to determine the specific association of EL with effectiveness outcomes at different levels, and identify important factors influencing this relationship, which broadens the understanding of leadership effectiveness and provides certain value for enterprises to give full play to the role of EL at all levels.
Anxious parents show higher physiological synchrony with their infants
Authors: Smith C. G. , Jones E. J. H. , Charman T. , Clackson K. , Mirza F. U. , Wass S. V.
Published: February 2021

Background

Interpersonal processes influence our physiological states and associated affect. Physiological arousal dysregulation, a core feature of anxiety disorders, has been identified in children of parents with elevated anxiety. However, little is understood about how parent–infant interpersonal regulatory processes differ when the dyad includes a more anxious parent.

Methods

We investigated moment-to-moment fluctuations in arousal within parent-infant dyads using miniaturised microphones and autonomic monitors. We continually recorded arousal and vocalisations in infants and parents in naturalistic home settings across day-long data segments.

Results

Our results indicated that physiological synchrony across the day was stronger in dyads including more rather than less anxious mothers. Across the whole recording epoch, less anxious mothers showed responsivity that was limited to ‘peak’ moments in their child's arousal. In contrast, more anxious mothers showed greater reactivity to small-scale fluctuations. Less anxious mothers also showed behaviours akin to ‘stress buffering’ – downregulating their arousal when the overall arousal level of the dyad was high. These behaviours were absent in more anxious mothers.

Conclusion

Our findings have implications for understanding the differential processes of physiological co-regulation in partnerships where a partner is anxious, and for the use of this understanding in informing intervention strategies for dyads needing support for elevated levels of anxiety.
Preserving cardinals and weak forms of Zorn’s lemma in realizability models
Authors: Fontanella Laura , Geoffroy Guillaume
Published: February 2021

We develop a technique for representing and preserving cardinals in realizability models, and we apply this technique to define a realizability model of Zorn’s lemma restricted to an ordinal.
RE-THINKING RACIALIZATION
Authors: Uyan Deniz
Published: February 2021

This paper seeks to scrutinize the most recent definition of racialization, as proposed by Adam Hochman, and interrogate its utility as a productive analytic for social scientists. Due to theoretical conflations between race and racism, and analytical conflations of groupness and category, racialization functions as a tautological descriptive rather than an agenda-setting theoretical framework for scholars studying race. The most recent definition of the concept cannot, and does not try to, account for a mechanism for the process of racialization. Such an accounting is a necessary component of any conceptualization that aims to help identify the origins of racialization. Second, in the absence of locating an agent or mechanism, the concept is tautologized: racialization, with an inability to locate a mechanism, offers itself up as the mechanism. Third, this tautologizing leads to a profound conflation of racialization offered as both a descriptive and a causal concept. Not only does this conflation halt the analytic capacity of the term as it applies to social scientific uses, but this conflation proves harmful for the anti-realist agenda as proposed by Hochman. By conflating analyses of causality with description, the latest definition of racialization unknowingly countersigns a uniquely American ideological conception of race; that is, the latest definition allows a description of the appearance of race to stand in for an explanation for race.
Impacts of Transboundary Dust Transport on Aerosol Pollution in the Western Yangtze River Delta Region, China: Insights Gained From Ground‐Based Lidar and Satellite Observations
Authors: Yang Hao , Fang Zhiyuan , Cao Ye , Xie Chenbo , Zhou Tian , Wang Bangxin , Xing Kunming , Lolli Simone
Published: February 2021

Dust storms pose a serious threat to air quality and public health through large‐scale, long‐distance transport. In early April 2018, two severe dust storm events occurred in the Taklimakan and Gobi Deserts in northwestern China. The advected air‐masses containing dust traveled eastward over long distances reaching the western Yangtze River Delta region (WYRDR) with local PM10 peak concentrations of 190 and 410 μg/m3 on April 6 and April 11, 2018, respectively. Satellite remote sensing and ground‐based lidar observations showed that the first dust event was transported to WYRDR at an altitude of <5 km, while the second transport height was at an altitude of <3 km. The first one was accompanied with the dry‐cold air mass in the northwest moving eastward and southward. By comparison, in the second event, the dust aerosols were mixed with anthropogenic aerosols from southwestern China. Meanwhile, as southerly warm‐humid air flows prevailed at near‐surface layer over the WYRDR in the second event, the associated higher relative humidity potentially induced hygroscopic growth of polluted dust aerosols, resulting in explosive growth of PM10. In addition, the average depolarization ratio of aerosols over WYRDR on April 6 was 0.3, while on April 11 it was 0.2, indicating that the previous pollution event featured more obvious nonspherical characteristics of aerosols. Our findings provide scientific evidence that transboundary dust events and resultant local PM10 pollution are closely related to various transport trajectories of dust aerosols as well as the local vertical wind profiles and surface humidity conditions.
Effects of the Plasmapause on the Radial Propagation of Fast Magnetosonic Waves: An Analytical Approach
Authors: Yu Xiongdong , Yuan Zhigang , Ouyang Zhihai , Yao Fei
Published: February 2021

In this study, analytical approximation is used to solve the wave equations near the plasmapause boundary layer in order to examine the validity of ray tracing approach for fast magnetosonic (MS) wave propagations, and then analytical solutions for electromagnetic fields of MS waves through the plasmapause boundary layer are provided for the first time. Both theoretical calculations from the analytical expressions and observations of Van Allen Probes have indicated that electric fields of MS waves decrease rapidly but magnetic fields increase rapidly when propagating across the plasmapause boundary layer from the outside. Considering effects of the plasmapause width and wave frequency, parameter analysis has shown that when the width of the plasmapause boundary layer is narrow in comparison with the wavelength of MS waves, a significant part of waves will be reflected. In these circumstances, the WKB approximation and then ray tracing method might become invalid, and analytical approach provided in this paper could be utilized to solve the wave equation.
Role of Equatorial Fountain for the Delayed Response of Thermosphere O1D 630.0 nm Dayglow Over the Dip Equator During an X‐Class Flare
Authors: Vineeth C. , Ambili K. M. , Pant T. K. , Subrahmanyam K. V.
Published: February 2021

This paper reports, for the “first time,” the delayed response of O1D 630.0 nm dayglow emissions over Trivandrum (8.5°N, 77°E, 0.5°N dip lat.), a geomagnetic dip equatorial station in India, to the noontime X‐class solar flare event of July 30, 2005. The dayglow measurements were made using a unique dayglow photometer operating at three wavelengths. The Equatorial Electrojet induced magnetic field, measured using a proton precession magnetometer, showed a magnetic spike having ∼90 nT enhancement during this flare with a time delay of ∼7.2 min. A noteworthy observation is that unlike to the conventional belief, the O1D 630.0 nm dayglow over the dip equator exhibited a fourfold enhancement during the noontime flare after a time delay of ∼45 min. Analysis of satellite measured electron density and modeling simulations indicate that the thermospheric O1D 630.0 nm dayglow emission over the dip equatorial region during a solar flare is primarily driven by the electrodynamics, rather than the direct solar control. This finding is new, unique and very important for the studies related to plasma‐neutral coupling and also for modeling studies on the equatorial thermosphere‐ionosphere region is concerned.
In Which Magnetotail Hemisphere is a Satellite? Problems Using in Situ Magnetic Field Data
Authors: De Spiegeleer A. , Hamrin M. , Gunell H. , Pitkänen T. , Chong S.
Published: February 2021

In Earth's magnetotail plasma sheet, the sunward‐tailward Bx component of the magnetic field is often used to separate the region above and below the cross‐tail current sheet. Using a three‐dimensional magneto‐hydrodynamic simulation, we show that high‐speed flows do not only affect the north‐south magnetic field component (causing dipolarization fronts), but also the sunward‐tailward component via the formation of a magnetic dent. This dent is such that, in the Northern Hemisphere, the magnetic field is tailward while in the Southern Hemisphere, it is earthward. This is opposite to the expected signatures where Bx > 0 (Bx < 0) above (below) the neutral sheet. Therefore, the direction of the magnetic field cannot always be used to identify in which hemisphere an in situ spacecraft is located. In addition, the cross‐tail currents associated with the dent is different from the currents in a tail without a dent. From the simulation, we suggest that the observation of a dawnward current and a tailward magnetic tension force, possibly together with an increase in the plasma beta, may indicate the presence of a magnetic dent. To exemplify, we also present data of a high‐speed flow observed by the Cluster mission, and we show that the changing sign of Bx is likely due to such a dent, and not to the spacecraft moving across the neutral sheet.
Whistlers in the Plasmasphere
Authors: Streltsov Anatoly V.
Published: February 2021

We study packages of VLF whistler‐mode waves observed by the Van Allen Probes satellites in the equatorial plasmasphere. We demonstrate that the main mechanism providing localization of these waves inside relatively broad (>1 RE across the ambient magnetic field) magnetospheric regions is a combined effect of the transverse gradients in the plasma density and the ambient magnetic field. The criterion for the wave trapping by these gradients is the same as for the wave trapping inside a high‐density duct with a symmetric, Gaussian‐like profile of the density in the uniform magnetic field. This criterion can be used to determine the parallel wavelength of the wave with a known frequency trapped by the density and magnetic field inhomogeneities with known parameters. The developed theoretical approach demonstrates a good, quantitative agreement with the observations. The analytical results have been confirmed with comprehensive, time‐dependent simulations of the electron‐MHD model.
Regional and Urban Column CO Trends and Anomalies as Observed by MOPITT Over 16 Years
Authors: Hedelius Jacob K. , Toon Geoffrey C. , Buchholz Rebecca R. , Iraci Laura T. , Podolske James R. , Roehl Coleen M. , Wennberg Paul O. , Worden Helen M. , Wunch Debra
Published: February 2021

Atmospheric carbon monoxide (CO) concentrations have decreased since the beginning of the century, and the rate of decrease depends on the region. Depending on how regions are chosen, their boundaries may not always align with where there are differences in trends. To address this, we calculate trends within 0.4° × 0.4° grid cells independently throughout the globe using satellite CO retrievals from the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument from 2002 to 2017. These trends are found with the caveat that there are large singular biomass burning events somewhere nearly every year, and we include examples of large column CO anomalies during sporadic but large burning events in the North American and Eurasian boreal forests, the Amazon, Africa, and Indonesia. CO trends behave similarly within regions that span about a few thousand kilometers. Using TransCom region definitions, we find average trends between −0.9 and 0.1 ppb year−1 (about −0.9 to 0.1% year−1) for 2002–2017. Over 5‐year subsets, trends in TransCom regions vary between −3.6 and 1.8 ppb year−1. This substantial spatial and temporal variability in trends is in agreement with other studies. With an understanding of regional trends, we compare with trends from urban areas. Generally, CO trends within urban areas are indistinguishable from regional trends. This may be because of a combination of noise in the data, the large footprint for MOPITT, or because anthropogenic CO reduction measures were implemented before the MOPITT record began. We provide case studies for a few cities, such as Los Angeles, and find long‐term variation in the rate of change of column CO.
Snow Avalanche Detection and Source Constraints Made Using a Networked Array of Infrasound Sensors
Authors: Johnson J. B. , Anderson J. F. , Marshall H. P. , Havens S. , Watson L. M.
Published: February 2021

We studied a triggered snow avalanche (∼60 s in duration and with ∼1,100 m run‐out) using a network of infrasound arrays and time‐synced video, with the objective of understanding the relationship between infrasound generation and flow dynamics. Using standard array processing techniques, we compared the infrasound source back azimuths with the avalanche flow path identified by frame‐differenced, geo‐referenced video. Results show that infrasound records begin with direct arrivals followed by echoes from the avalanche‐triggering explosions and these decay within 35 s of the detonations. Subsequent infrasound, which lasts 20–30 s, could then be attributed exclusively to the avalanche. These infrasound detections, and their triangulated source locations, progress downhill over time and the most intense infrasound appears to originate from a steep, mid‐path cliff band, where the avalanche reached speeds in excess of 30 m/s and accelerations of more than 5 m/s2. The recorded infrasound was compared to two candidate source models extracted from video: total flow motion and advancing flow motion. Advancing source locations were compared to acoustic intensity time series using a nonnegative least squares inversion to solve for, and to quantify, time‐varying infrasound source intensity. We observed that certain portions of the flow, most notably the early stages and the end stages (when the powder cloud was expanding and settling) were infrasonically quiet.
Variable inter and intraspecies alkaline phosphatase activity within single cells of revived dinoflagellates
Authors: Girault Mathias , Siano Raffaele , Labry Claire , Latimier Marie , Jauzein Cécile , Beneyton Thomas , Buisson Lionel , Del Amo Yolanda , Baret Jean-Christophe
Published: February 2021

Adaptation of cell populations to environmental changes is mediated by phenotypic variability at the single-cell level. Enzyme activity is a key factor in cell phenotype and the expression of the alkaline phosphatase activity (APA) is a fundamental phytoplankton strategy for maintaining growth under phosphate-limited conditions. Our aim was to compare the APA among cells and species revived from sediments of the Bay of Brest (Brittany, France), corresponding to a pre-eutrophication period (1940’s) and a beginning of a post-eutrophication period (1990’s) during which phosphate concentrations have undergone substantial variations. Both toxic marine dinoflagellate Alexandrium minutum and the non-toxic dinoflagellate Scrippsiella acuminata were revived from ancient sediments. Using microfluidics, we measured the kinetics of APA at the single-cell level. Our results indicate that all S. acuminata strains had significantly higher APA than A. minutum strains. For both species, the APA in the 1990’s decade was significantly lower than in the 1940’s. For the first time, our results reveal both inter and intraspecific variabilities of dinoflagellate APA and suggest that, at a half-century timescale, two different species of dinoflagellate may have undergone similar adaptative evolution to face environmental changes and acquire ecological advantages.
Tunable thermo-reversible bicontinuous nanoparticle gel driven by the binary solvent segregation
Authors: Xi Yuyin , Lankone Ronald S. , Sung Li-Piin , Liu Yun
Published: February 2021

Bicontinuous porous structures through colloidal assembly realized by non-equilibrium process is crucial to various applications, including water treatment, catalysis and energy storage. However, as non-equilibrium structures are process-dependent, it is very challenging to simultaneously achieve reversibility, reproducibility, scalability, and tunability over material structures and properties. Here, a novel solvent segregation driven gel (SeedGel) is proposed and demonstrated to arrest bicontinuous structures with excellent thermal structural reversibility and reproducibility, tunable domain size, adjustable gel transition temperature, and amazing optical properties. It is achieved by trapping nanoparticles into one of the solvent domains upon the phase separation of the binary solvent. Due to the universality of the solvent driven particle phase separation, SeedGel is thus potentially a generic method for a wide range of colloidal systems.
Power-law coarsening in network-forming phase separation governed by mechanical relaxation
Authors: Tateno Michio , Tanaka Hajime
Published: February 2021

A space-spanning network structure is a basic morphology in phase separation of soft and biomatter, alongside a droplet one. Despite its fundamental and industrial importance, the physical principle underlying such network-forming phase separation remains elusive. Here, we study the network coarsening during gas-liquid-type phase separation of colloidal suspensions and pure fluids, by hydrodynamic and molecular dynamics simulations, respectively. For both, the detailed analyses of the pore sizes and strain field reveal the self-similar network coarsening and the unconventional power-law growth more than a decade according toℓ ∝ t1/2, whereℓis the characteristic pore size andtis the elapsed time. We find that phase-separation dynamics is controlled by mechanical relaxation of the network-forming dense phase, whose limiting process is permeation flow of the solvent for colloidal suspensions and heat transport for pure fluids. This universal coarsening law would contribute to the fundamental physical understanding of network-forming phase separation.
Anti-inflammatory dopamine- and serotonin-based endocannabinoid epoxides reciprocally regulate cannabinoid receptors and the TRPV1 channel
Authors: Arnold William R. , Carnevale Lauren N. , Xie Zili , Baylon Javier L. , Tajkhorshid Emad , Hu Hongzhen , Das Aditi
Published: February 2021

The endocannabinoid system is a promising target to mitigate pain as the endocannabinoids are endogenous ligands of the pain-mediating receptors—cannabinoid receptors 1 and 2 (CB1 and CB2) and TRPV1. Herein, we report on a class of lipids formed by the epoxidation of N-arachidonoyl-dopamine (NADA) and N-arachidonoyl-serotonin (NA5HT) by epoxygenases. EpoNADA and epoNA5HT are dual-functional rheostat modulators of the endocannabinoid-TRPV1 axis. EpoNADA and epoNA5HT are stronger modulators of TRPV1 than either NADA or NA5HT, and epoNA5HT displays a significantly stronger inhibition on TRPV1-mediated responses in primary afferent neurons. Moreover, epoNA5HT is a full CB1 agonist. These epoxides reduce the pro-inflammatory biomarkers IL-6, IL-1β, TNF-α and nitrous oxide and raise anti-inflammatory IL-10 cytokine in activated microglial cells. The epoxides are spontaneously generated by activated microglia cells and their formation is potentiated in the presence of anandamide. Detailed kinetics and molecular dynamics simulation studies provide evidence for this potentiation using the epoxygenase human CYP2J2. Taken together, inflammation leads to an increase in the metabolism of NADA, NA5HT and other eCBs by epoxygenases to form the corresponding epoxides. The epoxide metabolites are bioactive lipids that are potent, multi-faceted molecules, capable of influencing the activity of CB1, CB2 and TRPV1 receptors.
Cryo-EM structures of engineered active bc1-cbb3 type CIII2CIV super-complexes and electronic communication between the complexes
Authors: Steimle Stefan , van Eeuwen Trevor , Ozturk Yavuz , Kim Hee Jong , Braitbard Merav , Selamoglu Nur , Garcia Benjamin A. , Schneidman-Duhovny Dina , Murakami Kenji , Daldal Fevzi
Published: February 2021

Respiratory electron transport complexes are organized as individual entities or combined as large supercomplexes (SC). Gram-negative bacteria deploy a mitochondrial-like cytochrome (cyt) bc1 (Complex III, CIII2), and may have specific cbb3-type cyt c oxidases (Complex IV, CIV) instead of the canonical aa3-type CIV. Electron transfer between these complexes is mediated by soluble (c2) and membrane-anchored (cy) cyts. Here, we report the structure of an engineered bc1-cbb3 type SC (CIII2CIV, 5.2 Å resolution) and three conformers of native CIII2 (3.3 Å resolution). The SC is active in vivo and in vitro, contains all catalytic subunits and cofactors, and two extra transmembrane helices attributed to cyt cy and the assembly factor CcoH. The cyt cy is integral to SC, its cyt domain is mobile and it conveys electrons to CIV differently than cyt c2. The successful production of a native-like functional SC and determination of its structure illustrate the characteristics of membrane-confined and membrane-external respiratory electron transport pathways in Gram-negative bacteria.
Potential health and economic impacts of dexamethasone treatment for patients with COVID-19
Authors: Águas Ricardo , Mahdi Adam , Shretta Rima , Horby Peter , Landray Martin , White Lisa ,   the CoMo Consortium, Arifi Fatima , Zhumalieva Chynar , Lubis Inke N. D. , Monteiro Antoninho Benjamin , Moldokmatova Ainura , Chen Siyu , Estebesova Aida , Hussain Mofakhar , Lata Dipti , Bakare Emmanuel A. , Getachew Biniam , Sahak Mohammad Nadir , Chanthavilay Phetsavanh , Nji Akindeh M. , Aung Yu Nandar , Hupert Nathaniel , Tun Sai Thein Than , Pan-Ngum Wirichada , Sarin K. C. , Harsono Handoyo , Eybpoosh Sana , Coutinho Renato Mendes , Omoleke Semeeh A. , Nwosu Amen-Patrick , Luangasanatip Nantasit , Kutmanova Ainura , Dooronbekova Aizhan , Ximenes Antonio , Monteiro Merita , Celhay Olivier , Adib Keyrellous , Salim Amel H. , Yunanda Yuki , Fariba Mahnaz Hossain , Azzeri Amirah , Hancock Penny , Bekrizadeh Hakim , Saeedzai Sayed Ataullah , Alona Ivana , Mzumara Grace Wezi , Martins Joao , Herrera-Diestra Jose L. , Sharifi Hamid , Abdyldaev Talant , Jamshidi Babak , Hairi Noran Naqiah , Nasir Naima , Zaman Rashid U. , Obiesie Sopuruchukwu , Kraenkel Roberto A. , Letchford Nicholas , Alves Lucsendar Raimunda Fernandes , Adele Sandra , Suárez-Idueta Lorena , Advani Nicole , Marzouk Manar , Mabombo Viviana , Mukambetov Aibek , Aderoba Adeniyi Kolade , Tbalasubramaniam Bpriya Lakshmy , de Colombi Nicole Feune , Niha Maria Angela Varela , Obando Francisco , Wattanasri Parinda , Saralamba Sompob , Shabaruddin Fatiha , Shimul Shafiun Nahin , Dahlui Maznah , Naidoo Reshania , Franco Caroline , Klein Michael G. , Kubatova Aisuluu , Jabin Nusrat , Kyaw Shwe Sin , Freitas Luzia Tomas , Pokharel Sunil , Ariana Proochista , Mercado Chris Erwin G. , Ibragimov Shamil , Medina John Robert C. , Namedre Mesulame
Published: February 2021

Dexamethasone can reduce mortality in hospitalised COVID-19 patients needing oxygen and ventilation by 18% and 36%, respectively. Here, we estimate the potential number of lives saved and life years gained if this treatment were to be rolled out in the UK and globally, as well as the cost-effectiveness of implementing this intervention. Assuming SARS-CoV-2 exposure levels of 5% to 15%, we estimate that, for the UK, approximately 12,000 (4,250 - 27,000) lives could be saved between July and December 2020. Assuming that dexamethasone has a similar effect size in settings where access to oxygen therapies is limited, this would translate into approximately 650,000 (240,000 - 1,400,000) lives saved globally over the same time period. If dexamethasone acts differently in these settings, the impact could be less than half of this value. To estimate the full potential of dexamethasone in the global fight against COVID-19, it is essential to perform clinical research in settings with limited access to oxygen and/or ventilators, for example in low- and middle-income countries.
Large-area integration of two-dimensional materials and their heterostructures by wafer bonding
Authors: Quellmalz Arne , Wang Xiaojing , Sawallich Simon , Uzlu Burkay , Otto Martin , Wagner Stefan , Wang Zhenxing , Prechtl Maximilian , Hartwig Oliver , Luo Siwei , Duesberg Georg S. , Lemme Max C. , Gylfason Kristinn B. , Roxhed Niclas , Stemme Göran , Niklaus Frank
Published: February 2021

Integrating two-dimensional (2D) materials into semiconductor manufacturing lines is essential to exploit their material properties in a wide range of application areas. However, current approaches are not compatible with high-volume manufacturing on wafer level. Here, we report a generic methodology for large-area integration of 2D materials by adhesive wafer bonding. Our approach avoids manual handling and uses equipment, processes, and materials that are readily available in large-scale semiconductor manufacturing lines. We demonstrate the transfer of CVD graphene from copper foils (100-mm diameter) and molybdenum disulfide (MoS2) from SiO2/Si chips (centimeter-sized) to silicon wafers (100-mm diameter). Furthermore, we stack graphene with CVD hexagonal boron nitride and MoS2 layers to heterostructures, and fabricate encapsulated field-effect graphene devices, with high carrier mobilities of up to $$4520\;{\mathrm{cm}}^2{\mathrm{V}}^{ - 1}{\mathrm{s}}^{ - 1}$$
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. Thus, our approach is suited for backend of the line integration of 2D materials on top of integrated circuits, with potential to accelerate progress in electronics, photonics, and sensing.
The tight Second Law inequality for coherent quantum systems and finite-size heat baths
Authors: Łobejko Marcin
Published: February 2021

In classical thermodynamics, the optimal work is given by the free energy difference, what according to the result of Skrzypczyk et al. can be generalized for individual quantum systems. The saturation of this bound, however, requires an infinite bath and ideal energy storage that is able to extract work from coherences. Here we present the tight Second Law inequality, defined in terms of the ergotropy (rather than free energy), that incorporates both of those important microscopic effects – the locked energy in coherences and the locked energy due to the finite-size bath. The former is solely quantified by the so-called control-marginal state, whereas the latter is given by the free energy difference between the global passive state and the equilibrium state. Furthermore, we discuss the thermodynamic limit where the finite-size bath correction vanishes, and the locked energy in coherences takes the form of the entropy difference. We supplement our results by numerical simulations for the heat bath given by the collection of qubits and the Gaussian model of the work reservoir.
Quantitative single-protein imaging reveals molecular complex formation of integrin, talin, and kindlin during cell adhesion
Authors: Fischer Lisa S. , Klingner Christoph , Schlichthaerle Thomas , Strauss Maximilian T. , Böttcher Ralph , Fässler Reinhard , Jungmann Ralf , Grashoff Carsten
Published: February 2021

Single-molecule localization microscopy (SMLM) enabling the investigation of individual proteins on molecular scales has revolutionized how biological processes are analysed in cells. However, a major limitation of imaging techniques reaching single-protein resolution is the incomplete and often unknown labeling and detection efficiency of the utilized molecular probes. As a result, fundamental processes such as complex formation of distinct molecular species cannot be reliably quantified. Here, we establish a super-resolution microscopy framework, called quantitative single-molecule colocalization analysis (qSMCL), which permits the identification of absolute molecular quantities and thus the investigation of molecular-scale processes inside cells. The method combines multiplexed single-protein resolution imaging, automated cluster detection, in silico data simulation procedures, and widely applicable experimental controls to determine absolute fractions and spatial coordinates of interacting species on a true molecular level, even in highly crowded subcellular structures. The first application of this framework allowed the identification of a long-sought ternary adhesion complex—consisting of talin, kindlin and active β1-integrin—that specifically forms in cell-matrix adhesion sites. Together, the experiments demonstrate that qSMCL allows an absolute quantification of multiplexed SMLM data and thus should be useful for investigating molecular mechanisms underlying numerous processes in cells.
In3SbTe2 as a programmable nanophotonics material platform for the infrared
Authors: Heßler Andreas , Wahl Sophia , Leuteritz Till , Antonopoulos Antonios , Stergianou Christina , Schön Carl-Friedrich , Naumann Lukas , Eicker Niklas , Lewin Martin , Maß Tobias W. W. , Wuttig Matthias , Linden Stefan , Taubner Thomas
Published: February 2021

The high dielectric optical contrast between the amorphous and crystalline structural phases of non-volatile phase-change materials (PCMs) provides a promising route towards tuneable nanophotonic devices. Here, we employ the next-generation PCM In3SbTe2 (IST) whose optical properties change from dielectric to metallic upon crystallization in the whole infrared spectral range. This distinguishes IST as a switchable infrared plasmonic PCM and enables a programmable nanophotonics material platform. We show how resonant metallic nanostructures can be directly written, modified and erased on and below the meta-atom level in an IST thin film by a pulsed switching laser, facilitating direct laser writing lithography without need for cumbersome multi-step nanofabrication. With this technology, we demonstrate large resonance shifts of nanoantennas of more than 4 µm, a tuneable mid-infrared absorber with nearly 90% absorptance as well as screening and nanoscale “soldering” of metallic nanoantennas. Our concepts can empower improved designs of programmable nanophotonic devices for telecommunications, (bio)sensing and infrared optics, e.g. programmable infrared detectors, emitters and reconfigurable holograms.
Divergent rhodium-catalyzed electrochemical vinylic C–H annulation of acrylamides with alkynes
Authors: Xing Yi-Kang , Chen Xin-Ran , Yang Qi-Liang , Zhang Shuo-Qing , Guo Hai-Ming , Hong Xin , Mei Tian-Sheng
Published: February 2021

α-Pyridones and α-pyrones are ubiquitous structural motifs found in natural products and biologically active small molecules. Here, we report an Rh-catalyzed electrochemical vinylic C–H annulation of acrylamides with alkynes, affording cyclic products in good to excellent yield. Divergent syntheses of α-pyridones and cyclic imidates are accomplished by employing N-phenyl acrylamides and N-tosyl acrylamides as substrates, respectively. Additionally, excellent regioselectivities are achieved when using unsymmetrical alkynes. This electrochemical process is environmentally benign compared to traditional transition metal-catalyzed C–H annulations because it avoids the use of stoichiometric metal oxidants. DFT calculations elucidated the reaction mechanism and origins of substituent-controlled chemoselectivity. The sequential C–H activation and alkyne insertion under rhodium catalysis leads to the seven-membered ring vinyl-rhodium intermediate. This intermediate undergoes either the classic neutral concerted reductive elimination to produce α-pyridones, or the ionic stepwise pathway to produce cyclic imidates.
Replication dynamics of recombination-dependent replication forks
Authors: Naiman Karel , Campillo-Funollet Eduard , Watson Adam T. , Budden Alice , Miyabe Izumi , Carr Antony M.
Published: February 2021

Replication forks restarted by homologous recombination are error prone and replicate both strands semi-conservatively using Pol δ. Here, we use polymerase usage sequencing to visualize in vivo replication dynamics of HR-restarted forks at an S. pombe replication barrier, RTS1, and model replication by Monte Carlo simulation. We show that HR-restarted forks synthesise both strands with Pol δ for up to 30 kb without maturing to a δ/ε configuration and that Pol α is not used significantly on either strand, suggesting the lagging strand template remains as a gap that is filled in by Pol δ later. We further demonstrate that HR-restarted forks progress uninterrupted through a fork barrier that arrests canonical forks. Finally, by manipulating lagging strand resection during HR-restart by deleting pku70, we show that the leading strand initiates replication at the same position, signifying the stability of the 3′ single strand in the context of increased resection.
The metabolic impact of small intestinal nutrient sensing
Authors: Duca Frank A. , Waise T. M. Zaved , Peppler Willem T. , Lam Tony K. T.
Published: February 2021

The gastrointestinal tract maintains energy and glucose homeostasis, in part through nutrient-sensing and subsequent signaling to the brain and other tissues. In this review, we highlight the role of small intestinal nutrient-sensing in metabolic homeostasis, and link high-fat feeding, obesity, and diabetes with perturbations in these gut-brain signaling pathways. We identify how lipids, carbohydrates, and proteins, initiate gut peptide release from the enteroendocrine cells through small intestinal sensing pathways, and how these peptides regulate food intake, glucose tolerance, and hepatic glucose production. Lastly, we highlight how the gut microbiota impact small intestinal nutrient-sensing in normal physiology, and in disease, pharmacological and surgical settings. Emerging evidence indicates that the molecular mechanisms of small intestinal nutrient sensing in metabolic homeostasis have physiological and pathological impact as well as therapeutic potential in obesity and diabetes.
SARS-CoV-2 antibody prevalence in England following the first peak of the pandemic
Authors: Ward Helen , Atchison Christina , Whitaker Matthew , Ainslie Kylie E. C. , Elliott Joshua , Okell Lucy , Redd Rozlyn , Ashby Deborah , Donnelly Christl A. , Barclay Wendy , Darzi Ara , Cooke Graham , Riley Steven , Elliott Paul
Published: February 2021

England has experienced a large outbreak of SARS-CoV-2, disproportionately affecting people from disadvantaged and ethnic minority communities. It is unclear how much of this excess is due to differences in exposure associated with structural inequalities. Here, we report from the REal-time Assessment of Community Transmission-2 (REACT-2) national study of over 100,000 people. After adjusting for test characteristics and re-weighting to the population, overall antibody prevalence is 6.0% (95% CI: 5.8-6.1). An estimated 3.4 million people had developed antibodies to SARS-CoV-2 by mid-July 2020. Prevalence is two- to three-fold higher among health and care workers compared with non-essential workers, and in people of Black or South Asian than white ethnicity, while age- and sex-specific infection fatality ratios are similar across ethnicities. Our results indicate that higher hospitalisation and mortality from COVID-19 in minority ethnic groups may reflect higher rates of infection rather than differential experience of disease or care.
Lighting up solid states using a rubber
Authors: Li Zhongyu , Wang Yanjie , Baryshnikov Gleb , Shen Shen , Zhang Man , Zou Qi , Ågren Hans , Zhu Liangliang
Published: February 2021

It is crucial and desirable to develop green and high-efficient strategies to regulate solid-state structures and their related material properties. However, relative to solution, it is more difficult to break and generate chemical bonds in solid states. In this work, a rubbing-induced photoluminescence on the solid states of ortho-pyridinil phenol family was achieved. This rubbing response relied on an accurately designed topochemical tautomerism, where a negative charge, exactly provided by the triboelectric effect of a rubber, can induce a proton transfer in a double H-bonded dimeric structure. This process instantaneously led to a bright-form tautomer that can be stabilized in the solid-state settings, leading to an up to over 450-fold increase of the fluorescent quantum yield of the materials. The property can be repeatedly used due to the reversibility of the tautomerism, enabling encrypted applications. Moreover, a further modification to the structure can be accomplished to achieve different properties, opening up more possibilities for the design of new-generation smart materials.