bluuebunny/crossref_metadata_2025 huggingface dataset:
Attuning to a changing ocean
Authors: Stenseth Nils Chr. , Payne Mark R. , Bonsdorff Erik , Dankel Dorothy J. , Durant Joël M. , Anderson Leif G. , Armstrong Claire W. , Blenckner Thorsten , Brakstad Ailin , Dupont Sam , Eikeset Anne M. , Goksøyr Anders , Jónsson Steingrímur , Kuparinen Anna , Våge Kjetil , Österblom Henrik , Paasche Øyvind
Published: August 2020

The ocean is a lifeline for human existence, but current practices risk severely undermining ocean sustainability. Present and future social−ecological challenges necessitate the maintenance and development of knowledge and action by stimulating collaboration among scientists and between science, policy, and practice. Here we explore not only how such collaborations have developed in the Nordic countries and adjacent seas but also how knowledge from these regions contributes to an understanding of how to obtain a sustainable ocean. Our collective experience may be summarized in three points: 1) In the absence of long-term observations, decision-making is subject to high risk arising from natural variability; 2) in the absence of established scientific organizations, advice to stakeholders often relies on a few advisors, making them prone to biased perceptions; and 3) in the absence of trust between policy makers and the science community, attuning to a changing ocean will be subject to arbitrary decision-making with unforeseen and negative ramifications. Underpinning these observations, we show that collaboration across scientific disciplines and stakeholders and between nations is a necessary condition for appropriate actions.
KAT5 acetylates cGAS to promote innate immune response to DNA virus
Authors: Song Ze-Min , Lin Heng , Yi Xue-Mei , Guo Wei , Hu Ming-Ming , Shu Hong-Bing
Published: August 2020

Significance

cGAS is a protein which senses the infected viral DNA in the cytosol. Sensing of viral DNA by cGAS signals an innate immune response to virus. How cGAS is regulated by posttranslational modifications is still not fully understood. In this study, we found that the acetyltransferase KAT5 mediated acetylation of the N terminus of cGAS after infection of DNA virus, such as herpes simplex virus 1. This modification of cGAS causes its higher affinity to viral DNA and therefore promotes innate antiviral response. This study helps to understand the delicate regulatory mechanisms of innate antiviral response. Manipulation of these mechanisms may help to develop novel therapeutics for infectious and inflammatory diseases.
Superconductivity in undoped BaFe
2
As
2
by tetrahedral geometry design
Authors: Kang Jong-Hoon , Kim Jong-Woo , Ryan Philip J. , Xie Lin , Guo Lu , Sundahl Chris , Schad Jonathon , Campbell Neil , Collantes Yesusa G. , Hellstrom Eric E. , Rzchowski Mark S. , Eom Chang-Beom
Published: August 2020

Significance

The results demonstrated here show superconductivity in the antiferromagnetic BaFe
2
As
2
without chemical substitution, by atomic level control of local structure through epitaxial superlattice design. The interfacial interactions modify the FeAs
4
tetrahedra via systematic control of tetragonal and orthorhombic structures, inducing superconductivity. This indicates structure and dimensionality play an important role in the superconducting properties in Fe-based superconductors, and opens a path to structural manipulation of superconductivity in ultrathin layers of Fe-based materials. This is likely to play a major role in understanding and developing Fe-based superconductors.
Efficient and nontoxic biomolecule delivery to primary human hematopoietic stem cells using nanostraws
Authors: Schmiderer Ludwig , Subramaniam Agatheeswaran , Žemaitis Kristijonas , Bäckström Alexandra , Yudovich David , Soboleva Svetlana , Galeev Roman , Prinz Christelle N. , Larsson Jonas , Hjort Martin
Published: August 2020

Significance

Primary stem cells are difficult to transfect, and their viability and function are impaired by traditional transfection methods. We show that nanostraws can be used to deliver RNA to primary human hematopoietic stem cells without any detectable negative effects. Nanostraw-treated cells show no alterations in gene expression and fully retain their proliferative capacity and their potential to regenerate blood cells of different lineages in vivo. This nonperturbative transfection method can benefit functional studies and clinical applications where minimal impact on stem cell function and viability is required.
Significant Zr isotope variations in single zircon grains recording magma evolution history
Authors: Guo Jing-Liang , Wang Zaicong , Zhang Wen , Moynier Frédéric , Cui Dandan , Hu Zhaochu , Ducea Mihai N.
Published: August 2020

Significance

Zircon, a common accessory mineral in crustal rocks, records plentiful and critical information on the Earth’s history. The isotopes of its major component, Zr, could be another powerful but unexplored tracer. We apply high-precision, high–spatial-resolution, in situ laser ablation Zr isotope measurements of magmatic zircons in continental arc plutonic rocks. Single zircon grains show impressive internal zoning with lighter Zr isotopes in the core but heavier ones toward the rim, solving a fundamental but controversial issue on how zircon fractionates Zr isotope in evolving magmas. Our results also reveal a strong temperature dependence of Zr isotopic fractionation. The Zr isotope is thus very promising in deciphering the differentiation history of magmatic systems and possibly the continental crust through time.
Covariation of fetal skull and maternal pelvis during the perinatal period in rhesus macaques and evolution of childbirth in primates
Authors: Kawada Mikaze , Nakatsukasa Masato , Nishimura Takeshi , Kaneko Akihisa , Morimoto Naoki
Published: August 2020

Significance

Childbirth is frequently difficult for humans due to a cephalocaudally short and dorsoventrally deep pelvis necessary for upright bipedality and a large neonatal brain. A tight fit between the neonatal head and maternal pelvic dimensions is, however, found not only in humans, but also in some other primate taxa. The rhesus macaques show human-like cephalopelvic proportions. We show that forms of the fetal skull and maternal pelvis during the perinatal period covary in ways to relax the obstructions of childbirth in rhesus macaques. This indicates that morphological covariation of the fetal skull and maternal pelvis could have evolved not only in humans, but also in other primates in parallel, or it could be an example of a catarrhine synapomorphy.
Divergence of rodent and primate medial frontal cortex functional connectivity
Authors: Schaeffer David J. , Hori Yuki , Gilbert Kyle M. , Gati Joseph S. , Menon Ravi S. , Everling Stefan
Published: August 2020

Significance

The question of the whether rodent and primate medial frontal cortex (MFC) share similar functional organization, and whether the rodent medial frontal cortex is functionally analogous to the primate lateral prefrontal cortex (LPFC) is a contentious issue. Here, we probe this long-standing question by comparing whole-brain functional connectivity of the MFC in rodents, nonhuman primates (marmosets), and humans. The results demonstrated a remarkably similar intrinsic functional organization of the MFC across the three species, but clear differences between rodent and primate MFC whole-brain connectivity. Furthermore, in contrast to the common proposal that the rat MFC is functionally analogous with the primate LFC, our results demonstrate clear differences between the rodent MFC and primate LFC interareal functional connectivity.
Immune signatures of prodromal multiple sclerosis in monozygotic twins
Authors: Gerdes Lisa Ann , Janoschka Claudia , Eveslage Maria , Mannig Bianca , Wirth Timo , Schulte-Mecklenbeck Andreas , Lauks Sarah , Glau Laura , Gross Catharina C. , Tolosa Eva , Flierl-Hecht Andrea , Ertl-Wagner Birgit , Barkhof Frederik , Meuth Sven G. , Kümpfel Tania , Wiendl Heinz , Hohlfeld Reinhard , Klotz Luisa
Published: August 2020

Significance

Multiple sclerosis is an autoimmune disease shaped by genetic and environmental factors. Because of the heterogeneity of the human population, it has been difficult to identify “immune signatures” of the disease. Here we investigated a cohort of identical twin pairs who are discordant for multiple sclerosis. In each twin pair, the immune signatures were remarkably similar, pointing to a strong influence of shared genetic and environmental factors. However, when we focused on a subgroup of seemingly healthy cotwins who showed subtle signs of “subclinical neuro-inflammation,” we identified a distinct signature of memory T cells. Insight into the immunological mechanisms associated with the initiation of the disease is relevant not only to the therapy but also for prevention of the disease.
Selenoprotein N is an endoplasmic reticulum calcium sensor that links luminal calcium levels to a redox activity
Authors: Chernorudskiy Alexander , Varone Ersilia , Colombo Sara Francesca , Fumagalli Stefano , Cagnotto Alfredo , Cattaneo Angela , Briens Mickael , Baltzinger Mireille , Kuhn Lauriane , Bachi Angela , Berardi Andrea , Salmona Mario , Musco Giovanna , Borgese Nica , Lescure Alain , Zito Ester
Published: August 2020

Significance

Selenoprotein N (SEPN1) is a type II transmembrane protein of the endoplasmic reticulum (ER) that senses luminal calcium through an EF-hand domain. On calcium depletion, a SEPN1 oligomer, prevalent under basal calcium concentrations, dissociates to generate a monomeric polypeptide that has enhanced redox trapping potential for its target the calcium pump, SERCA2, as well as for many additional interactors, indicating enhanced reductase activity. Our studies not only support that SEPN1 is one of the long-sought reductases of the ER, but also identify a feedback mechanism through which SEPN1 senses the luminal calcium level to modulate downstream signal transduction. Our results suggest that SEPN1 regulates the SERCA-mediated replenishment of ER calcium stores, a crucial mechanism for excitation-contraction coupling in skeletal muscle.
The motley drivers of heat and cold exposure in 21st century US cities
Authors: Broadbent Ashley Mark , Krayenhoff Eric Scott , Georgescu Matei
Published: August 2020

Significance

We present climate projections of population-weighted heat and cold exposure that directly and simultaneously account for greenhouse gas (GHG) and urban development-induced warming. Previous population heat and cold exposure estimates have not accounted for urban development-induced climate impacts, have neglected interactions between urban development-induced warming and GHG-induced climate change, and have used fixed temperature thresholds that may be inappropriate for some cities. We develop a more detailed and nuanced definition of extreme heat and cold exposure through key innovations, and our predicted exposure is substantially greater than previous assessments. Our results demonstrate that Sunbelt cities are projected to undergo the largest relative increase in population heat exposure to locally defined extreme heat conditions during the 21st century.
Root angle modifications by the
DRO1
homolog improve rice yields in saline paddy fields
Authors: Kitomi Yuka , Hanzawa Eiko , Kuya Noriyuki , Inoue Haruhiko , Hara Naho , Kawai Sawako , Kanno Noriko , Endo Masaki , Sugimoto Kazuhiko , Yamazaki Toshimasa , Sakamoto Shingo , Sentoku Naoki , Wu Jianzhong , Kanno Hitoshi , Mitsuda Nobutaka , Toriyama Kinya , Sato Tadashi , Uga Yusaku
Published: August 2020

Significance

Genetically improving the root system architectures of plants is an effective strategy for developing climate-resilient crops. In this study, we revealed that a cloned rice quantitative trait locus associated with root growth angle,
qSOR1
, is a
DRO1
homolog involved in root gravitropic responses. The loss-of-function allele
qsor1
resulted in roots that developed on the soil surface and enabled plants to avoid the reducing stress found in saline paddy soils and, consequently, increased yields. We show that the
DRO1
homologs could be useful for the controlled breeding of root system architectures that are adapted to the abiotic stress conditions caused by global climate change.
Diel variability of methane emissions from lakes
Authors: Sieczko Anna K. , Duc Nguyen Thanh , Schenk Jonathan , Pajala Gustav , Rudberg David , Sawakuchi Henrique O. , Bastviken David
Published: August 2020

Significance

Methane (CH
4
) emissions from lakes are significant, yet still highly uncertain and a key bottleneck for understanding the global methane budget. Current lake flux estimates do not account for diel variability of CH
4
flux. Here, we apply a high-resolution spatiotemporal measurement approach in multiple lakes and report extensive data on variability between day and night lake CH
4
emissions. Our results demonstrate a clear and consistent diel pattern with more than twofold higher daytime fluxes. We show that it is critical to include diel variability to correctly estimate and extrapolate lake CH
4
flux, and that present northern lake emissions may have been overestimated by 15%.
Psychological foundations of human status allocation
Authors: Durkee Patrick K. , Lukaszewski Aaron W. , Buss David M.
Published: August 2020

Significance

Social status is a universal and consequential dimension of variation within human groups. Multiple prominent theories have been proposed to explain how status is allocated, but extant evidence is insufficient to adjudicate between their conflicting predictions. Here we show that distinctions between each theory hinge on the relative importance of four key affordance dimensions: benefit-generation ability, benefit-generation willingness, cost-infliction ability, and cost-infliction willingness. Each theory makes a different prediction about the role of each affordance in status allocation. We test these competing predictions to explain status allocations across 14 nations. We found that benefit-generation affordances uniquely predicted status allocations across nations, whereas cost-infliction affordances were weak or null competing predictors.
NusG controls transcription pausing and RNA polymerase translocation throughout the
Bacillus subtilis
genome
Authors: Yakhnin Alexander V. , FitzGerald Peter C. , McIntosh Carl , Yakhnin Helen , Kireeva Maria , Turek-Herman Joshua , Mandell Zachary F. , Kashlev Mikhail , Babitzke Paul
Published: August 2020

Significance

Transcription can be transiently halted by pausing of RNAP, which provides additional time for gene regulatory events to occur. NusG is a universally conserved transcription elongation factor that was known to stimulate pausing at two positions in the
Bacillus subtilis
genome, both of which regulated expression of the downstream gene. Using genome-wide sequencing of nascent RNA, we identified thousands of pause sites in
B. subtilis
including 1,600 NusG-dependent pause sites. NusG induces pausing of RNAP in response to a conserved TTNTTT sequence motif in the nontemplate DNA strand within the paused transcription bubble. NusG-dependent pausing was confirmed at several pause sites in vitro. NusG-dependent pausing in the
ribD
riboswitch decreases the concentration of flavin mononucleotide required to regulate
ribD
expression.
TheAtoh7remote enhancer provides transcriptional robustness during retinal ganglion cell development
Authors: Miesfeld Joel B. , Ghiasvand Noor M. , Marsh-Armstrong Brennan , Marsh-Armstrong Nicholas , Miller Eric B. , Zhang Pengfei , Manna Suman K. , Zawadzki Robert J. , Brown Nadean L. , Glaser Tom
Published: August 2020

Significance

Vertebrate retinal ganglion cells (RGCs) transmit all visual signals from the eye to the brain, are the pathogenic target in glaucoma, and require the Atoh7 competence factor to develop from multipotent progenitors.Atoh7transcription is controlled by dualcisregulatory elements, including a remote shadow enhancer (SE). In humans, loss of the SE causes NCRNA disease, with congenital blindness due to optic nerve aplasia. We generated a mouseAtoh7SE deletion model and analyzed its effects on transcription, retinal histology, and chromatin architecture. The mutant mice express 80% lessAtoh7mRNA but retain optic nerves, unlike NCRNA patients. By systematically varying dosage in a genotypic series, we show how the dual enhancers maintain robust plasticity during RGC genesis.
Color-neutral, semitransparent organic photovoltaics for power window applications
Authors: Li Yongxi , Guo Xia , Peng Zhengxing , Qu Boning , Yan Hongping , Ade Harald , Zhang Maojie , Forrest Stephen R.
Published: August 2020

Significance

We demonstrate a semitransparent organic photovoltaic cell that achieves a power conversion efficiency of 10.8% and visible transparency of ∼50% using a nonfullerene acceptor (NFA) featuring strong near-infrared (NIR) absorption and simple synthesis. Contrary to expectations, stronger NIR absorption and closer molecular packing are obtained by employing an additive in these partially, instead of fully fused, rigid NFAs. By combining NIR-absorbing material sets with an optical outcoupling structure as well as transparent electrode, we overcome the trade-offs between efficiency, transparency, and device appearance. These results surpass other semitransparent solar cell technologies based on organic and other thin-film materials systems, showing a promising future for ST-OPVs as power-generating windows and other solar energy harvesting applications.
Rapid formation of human immunodeficiency virus-like particles
Authors: Bednarska Joanna , Pelchen-Matthews Annegret , Novak Pavel , Burden Jemima J. , Summers Peter A. , Kuimova Marina K. , Korchev Yuri , Marsh Mark , Shevchuk Andrew
Published: August 2020

Significance

Currently, our knowledge of individual virus particle assembly kinetics is based solely on studies of the dynamics of fluorescent puncta corresponding to the viral structural protein called Gag labeled with fluorescent proteins (e.g., green fluorescent protein [GFP]) observed by fluorescence microscopy in membranes of cells. However, GFP tagging affects virus particle assembly and release. We directly measured topological changes during HIV-like particle assembly and found that they can reach full size in 20 s and release in 0.5 to 3 min. Compared to previous estimates of ∼8-min assembly time and 30- to 60-min release time, this is more than 10 times faster. In our opinion this is a highly important discovery that challenges current views on virus replication mechanisms.
NTRK2
methylation is related to reduced PTSD risk in two African cohorts of trauma survivors
Authors: Vukojevic Vanja , Coynel David , Ghaffari Navid R. , Freytag Virginie , Elbert Thomas , Kolassa Iris-Tatjana , Wilker Sarah , McGaugh James L. , Papassotiropoulos Andreas , de Quervain Dominique J.-F.
Published: August 2020

Significance

In the present study we investigated the epigenetic pattern of genes involved in the regulation of glucocorticoid receptor signaling in two African populations of heavily traumatized individuals. The strongest link between regional methylation and posttraumatic stress disorder (PTSD) risk and symptoms was observed for
NTRK2
, which has been shown to play an important role in memory formation.
NTRK2
methylation was not related to trauma load, suggesting that methylation differences preexisted the trauma. Furthermore,
NTRK2
methylation was found to be related to memory and memory-related brain activity in healthy nontraumatized individuals. The present findings suggest that epigenetic modifications of
NTRK2
are involved in memory modulation in health, and in influencing risk and symptoms of PTSD in case of traumatic experiences.
A specialized population of Periostin-expressing cardiac fibroblasts contributes to postnatal cardiomyocyte maturation and innervation
Authors: Hortells Luis , Valiente-Alandi Iñigo , Thomas Zachary M. , Agnew Emma J. , Schnell Dan J. , York Allen J. , Vagnozzi Ronald J. , Meyer Evan C. , Molkentin Jeffery D. , Yutzey Katherine E.
Published: August 2020

Significance

During the postnatal period, the heart undergoes important changes, including cardiomyocyte cell-cycle arrest and loss of regenerative capacity. While other cell types have been better characterized, the information related to postnatal cardiac fibroblasts (CFs) is limited. Here, we report a specialized population of highly proliferative periostin-expressing (Postn+) fibroblasts in the early postnatal heart that become quiescent at P30. In comparison, P7 Tcf21+ fibroblasts have distinct gene expression from Postn+ CFs. Notably, Postn+ CFs express proliferation and neuronal-related genes, while Tcf21+ CFs preferentially express extracellular-matrix–related genes. Ablation of Postn+ cells leads to reduced cardiomyocyte growth, mitotic activity, and binucleation with increased sympathetic nerve area. Thus Postn+ cells represent a specialized developmental CF population critical for postnatal cardiac maturation.
How a B family DNA polymerase has been evolved to copy RNA
Authors: Choi Woo Suk , He Peng , Pothukuchy Arti , Gollihar Jimmy , Ellington Andrew D. , Yang Wei
Published: August 2020

Significance

RTX is a reverse transcriptase evolved in vitro from the B family DNA polymerase KOD. Structural analyses of RTX in complex with either a DNA duplex or an RNA–DNA hybrid and comparison with the apo, binary, and ternary complex structures of the original KOD polymerase shed light on how to engineer and alter substrate specificity of enzymes. Among the 16 substitutions that result in the reverse transcriptase activity, only six occur at the substrate-binding surface, and the others change domain–domain interfaces in the polymerase to enable RNA–DNA hybrid binding and reverse transcription. The intrinsically flexible Thumb domain seems to play a major role in accommodating the RNA–DNA hybrid product distal to the active site.
Constraining crustal silica on ancient Earth
Authors: Keller C. Brenhin , Harrison T. Mark
Published: August 2020

Significance

On geologic timescales, Earth’s habitable climate is maintained by a negative feedback process wherein atmosphericCO2is consumed by reaction with silicate rocks during erosion and weathering. However, relative to modern continental crust, many models propose an ancient crust that was thinner, denser, and significantly lower in silica for the first 1 to 2 billion years of Earth history. Like modern oceanic crust, such mafic crust would likely be poorly exposed to the atmosphere, resulting in a less climatically stable early Earth. We find that two geologic processes (mantle cooling and atmospheric oxidation) significantly compromise some previous methods for estimating ancient crustal composition. Accounting for these factors results in estimates much closer to the composition of modern continental crust.
The glutathione peroxidase 8 (GPX8)/IL-6/STAT3 axis is essential in maintaining an aggressive breast cancer phenotype
Authors: Khatib Anees , Solaimuthu Balakrishnan , Ben Yosef Michal , Abu Rmaileh Areej , Tanna Mayur , Oren Gidi , Schlesinger Frisch Michal , Axelrod Jonathan H. , Lichtenstein Michal , Shaul Yoav D.
Published: August 2020

Significance

The cancer-dependent metabolic rewiring is mainly associated with the synthesis of building blocks that are needed to fulfill the proliferating cell metabolic requirements. However, the proliferation-independent instructive role of metabolic enzymes in tumor plasticity is still unclear. Here, we introduce glutathione peroxidase 8 (GPX8) as a metabolic enzyme that regulates cancer aggressiveness. We found that lack of GPX8 suppresses the aggressive phenotype and stemness features of the tumor cells. Mechanistically, these cells express a nonfunctional IL-6 receptor, which fails to interact with IL-6. This impaired binding hinders the activation of the downstream JAK/STAT3 signaling pathway, thereby inhibiting cancer cells transition to aggressive phenotypes. Thus, we present this GPX8/IL-6/STAT3 axis as a prototype of metabolic enzymes regulating cancer aggressiveness-associated signaling pathways.
Autoantibodies against central nervous system antigens in a subset of B cell–dominant multiple sclerosis patients
Authors: Kuerten Stefanie , Lanz Tobias V. , Lingampalli Nithya , Lahey Lauren J. , Kleinschnitz Christoph , Mäurer Mathias , Schroeter Michael , Braune Stefan , Ziemssen Tjalf , Ho Peggy P. , Robinson William H. , Steinman Lawrence
Published: August 2020

Significance

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS). B cells play a key role in MS immunopathology, as demonstrated by the success of B cell-directed therapies; however, the target antigen of MS remains unknown. Using a combination of ELISpot-based prescreening of peripheral blood mononuclear cells followed by investigation of antibody specificity with a CNS antigen array, we identified a population of MS patients characterized by a highly active B cell response. These individuals with MS, who have active B cell responses, exhibited heterogeneous interindividual anti-CNS antibody responses, although the antigenic specificity of the antibodies remained stable over time for each individual.
Extended dilation of the radiocarbon time scale between 40,000 and 48,000 y BP and the overlap between Neanderthals and
Homo sapiens
Authors: Bard Edouard , Heaton Timothy J. , Talamo Sahra , Kromer Bernd , Reimer Ron W. , Reimer Paula J.
Published: August 2020

The new radiocarbon calibration curve (IntCal20) allows us to calculate the gradient of the relationship between
14
C age and calendar age over the past 55 millennia before the present (55 ka BP). The new gradient curve exhibits a prolonged and prominent maximum between 48 and 40 ka BP during which the radiocarbon clock runs almost twice as fast as it should. This radiocarbon time dilation is due to the increase in the atmospheric
14
C/
12
C ratio caused by the
14
C production rise linked to the transition into the Laschamp geomagnetic excursion centered around 41 ka BP. The major maximum in the gradient from 48 to 40 ka BP is a new feature of the IntCal20 calibration curve, with far-reaching impacts for scientific communities, such as prehistory and paleoclimatology, relying on accurate ages in this time range. To illustrate, we consider the duration of the overlap between Neanderthals and
Homo sapiens
in Eurasia.
Pancreatic cancer SLUGged
Authors: Josselsohn Rachel H. , Tuveson David A.
Published: August 2020

In this issue of JEM, Recouvreux et al. (https://doi.org/10.1084/jem.20200388) describe the role of nutrient sensing in the induction of epithelial–mesenchymal transition. Glutamine-deficient pancreatic cancer cells up-regulate classic EMT regulator Slug, providing a link between nutrient stress and metastasis.
Probing primordial stochastic gravitational wave background with multi-band astrophysical foreground cleaning
Authors: Pan Zhen , Yang Huan
Published: August 2020

The primordial stochastic gravitational wave background (SGWB) carries first-hand messages of early-universe physics, possibly including effects from inflation, preheating, cosmic strings, electroweak symmetry breaking, and etc. However, the astrophysical foreground from compact binaries may mask the SGWB, introducing difficulties in detecting the signal and measuring it accurately. In this paper, we propose a foreground cleaning method taking advantage of gravitational wave observations in other frequency bands. We apply this method to probing the SGWB with space-borne gravitational wave detectors, such as the laser interferometer space antenna (LISA). We find that the spectral density of the LISA-band astrophysical foreground from compact binaries (black holes and neutron stars) can be predicted with percent-level accuracy assuming 10-years’ observations of third-generation GW detectors, e.g., cosmic explorer. While this multi-band method does not apply to binary white dwarfs (BWDs) which usually merger before entering the frequency band of ground-based detectors, we limit our foreground cleaning to frequency higher than ∼5 mHz, where all galactic BWDs can be individually resolved by LISA and the shape of the spectral density of the foreground from extragalactic BWDs can be reconstructed and/or modeled with certain uncertainties. After the foreground cleaning, LISA’s sensitivity to the primordial SGWB will be substantially improved for either two LISA constellations where SGWB can be measured by cross correlating their outputs or only one constellation with three spacecrafts where SGWB can be measured by contrasting the responses of a signal channel and a null channel.
Influence of the residual gas damping noise in the test of the gravitational inverse-square law
Authors: Ke Jun , Luo Jie , Tan Yu-Jie , Shao Cheng-Gang
Published: August 2020

Many theories, such as the unification theories that would include gravitation, predict deviations from Newtonian inverse-square law (ISL) at short range. Many high precision experiments have been performed, but additional experiments are still of high scientific importance. Here, we discuss the torque thermal noise caused by residual gas damping, especially the effect of squeeze-film damping, in a proposed ISL experiment at the range of tens of microns. In such experiments, torsion pendulums are usually used to probe the torque interactions between the detector and the attractor, of which the thermal noise should be considered carefully due to the high sensitivity. By introducing a thermal accommodation coefficient, we can accurately model the torque noise of the residual gas damping as a combination of elastic and inelastic collisions. The results show that the noise will increase significantly at short separations between the pendulum and the surrounding components. In particular, when the separation is smaller than 40 μm, the squeeze-film damping may be larger than the internal damping of the pendulum used in present experiments, and become the fundamental limit for the experiments in the shorter range.
A second order Calderón’s method with a correction term and a priori information
Authors: Shin Kwancheol , Mueller Jennifer L
Published: August 2020

Calderón’s method is a direct linearized reconstruction method for the inverse conductivity problem with the attribute that it can provide absolute images of both conductivity and permittivity with no need for forward modeling. In this work, an explicit relationship between Calderón’s method and the D-bar method is provided, facilitating a ‘higher-order’ Calderón’s method in which a correction term is included, derived from the relationship to the D-bar method. Furthermore, a method of including a spatial prior is provided. These advances are demonstrated on simulated data and on tank data collected with the ACE1 EIT system.
Positron scattering and transport in liquid helium
Authors: Cocks D G , McEachran R P , Boyle G J , Cheng E , White R D
Published: August 2020

In previous papers we have proposed a method for the ab initio calculation of fully differential cross-sections for electron scattering in liquids and applied it to liquid argon, xenon and krypton. In this paper, we extend the procedure to the consideration of positron scattering in liquid helium, which is complicated by the annihilation process as well as the fact that the electron definition for the region ‘owned’ by a target atom used previously does not have a positron analogue. We explore several physically motivated definitions to obtain effective positron scattering in the dense fluid. We find that our calculations of a pure helium system cannot precisely match experimental measurements, however by including a small admixture (<0.1%) of an impurity, we can obtain reasonable agreement in the dense gas phase. In contrast, the comparison between our calculations and liquid phase measurements is less satisfactory. This provides motivation to explore further multiple scattering effects in the theory.
The use of oscillator-strength sum rules for evaluating the angular-momentum dependence of the blackbody-radiation-induced broadening and shift of Rydberg-state energy levels
Authors: Glukhov I L , Kamenski A A , Ovsiannikov V D
Published: August 2020

First evaluations of the blackbody-radiation (BBR)-induced shift and broadening of highly excited Rydberg states were based on the account of only the first term of the expansion for the Planck’s distribution in powers of the ratio of the BBR-photon energy to the environmental thermal energy. The corresponding asymptotic expression for the shift is proportional to a sum rule for the oscillator strengths, which is identical for all states, independently of their principal and angular-momentum quantum numbers. The broadening appeared proportional to the sum of the oscillator-strength first moments, which is dependent on only the principal quantum number, being independent of the state’s angular momentum. In this article, we demonstrate that the account of higher-order terms of the Planck’s distribution expansion provides corrections revealing the dependence of asymptotic shift and broadening on the Rydberg-state principal and angular-momentum quantum numbers. The strongest corrections are observed for states with low angular momenta, in agreement with earlier performed numerical calculations. Sum rules for higher moments of oscillator strengths are used for evaluating the corrections for the BBR-induced broadening and shift of Rydberg-state energy levels in neutral atoms and ions of arbitrary nuclear charge Z.
Ion beam modification of the Ni-Si solid-phase reaction: The influence of substrate damage and nitrogen impurities introduced by ion implantation
Authors: van Stiphout K , Geenen F A , Santos N M , Miranda S M C , Joly V , Demeulemeester J , Mocuta C , Comrie C M , Detavernier C , Pereira L M C , Temst K , Vantomme A
Published: August 2020

We report on the growth of thin NiSi films via the thermal reaction of Ni layers (13–35 nm) with Si(100) substrates modified by ion implantation. By introducing substrate damage or nitrogen impurities prior to the solid-phase reaction, several properties of the NiSi films can be modified: the formation temperature, texture, diffusion-limited growth rate and morphological stability. As some of the modifications to the NiSi films are rooted in the early silicide phases preceding the NiSi phase, particularly its formation temperature, special attention is devoted to the growth of the amorphous Ni-Si alloy and the crystalline δ-Ni2Si and θ-Ni2Si phases.

We employed a number of experimental techniques, including in situ synchrotron x-ray diffraction (XRD), in situ Rutherford backscattering spectrometry (RBS), in situ sheet resistance measurements, ex situ ion beam channelling and ex situ pole figure measurements. We show that both the formation temperature of the NiSi films and the intensity of epitaxial and axiotaxial components of the NiSi texture can be either lowered or raised by selecting appropriate implantation conditions. Agglomeration of the NiSi films at high temperature (> 700 °C) can be slowed down, either by slowing down the mobility of the Ni and Si atoms, or by removing the morphologically destabilizing axiotaxial texture. Our results emphasize the strong interwoven nature of phase formation, texture and morphological degradation. We illustrate that the kinetics of the early stages of thin film reactions consist of more than just diffusion, i.e. nucleation can also play a crucial role.
Modelling of time development of cylindrical underwater spark channel in compressible viscous liquid
Authors: Kolacek Karel , Stelmashuk Vitaliy , Tuholukov Andrii , Hoffer Petr , Schmidt Jiri , Straus Jaroslav , Frolov Alexandr , Oliva Eduardo
Published: August 2020

In this study, a new finite-difference cylindrical model of long underwater spark is developed that allows us to numerically calculate the time evolution of the underwater spark channel from a given power input. A one dimensional simulation starts in the breakdown moment. The whole time development is divided into time steps of equal duration. The investigated region consists of a homogeneous cylindrical central column filled with weakly ionized vapour and its atomic fragments, and co-axial cylindrical liquid slabs of equal thickness in the beginning. In each time step, some energy (experimentally given and reduced by losses spent on dissociation, excitation, and ionization) is delivered into the central plasma column. This energy is partly irradiated, out-conducted, spent on mechanical work, and/or used for an increase of inner energy of the plasma column. This ambiguity enables us in future to fit, e.g. the plasma column diameter at the end of energy input to its experimental value. The model shows that plasma channel expansion generates a primary pressure wave propagating with supersonic velocity, and a subsequent secondary pressure wave that propagates with sound velocity. An advantage of this approach is that the present solution with constant coefficients can be relatively easily upgraded to a solution with variable coefficients.
Interface charge accumulation dynamics in 3D and quasi-2D perovskite solar cells
Authors: Liu Guilin , Zhou Ning , Tan Shunquan , Zhang Juchen , Chen Qi , Zhou Huanping
Published: August 2020

Perovskite solar cells (PSCs) have rapidly developed in recent years with the advantages of high efficiency and low cost. Although PSCs are the fastest-advancing solar technology to date, bottlenecks such as J–V hysteresis have limited the further development significantly. In this work, we have investigated the in-depth mechanism of hysteresis in both three-dimensional (3D) and quasi-2D (Q-2D) planar p-i-n PSCs. We conducted scanning-rate-dependent and temperature-dependent measurements to distinguish the ion migration and the capacitive charging. The coefficient for capacitance and pseudocapacitance from the J–V curves are further employed to analysis the hysteresis. It is found that both capacitance and ion migration contribute to the J–V hysteresis, but play different roles in 3D and Q-2D perovskite devices. In 3D PSCs, the ion migration has substantial impacts on the J–V hysteresis, wherein ions are tending to move. While in the Q-2D PSCs, the capacitance extends the characteristic charging time, which is mainly responsible for J–V hysteresis. These findings will help to effectively suppress the hysteresis for 3D and Q-2D PSCs, eventually benefiting device performance and long term stability.
Graphite films/carbon fiber fabric/ polyurethane composites with ultrahigh in-plane thermal conductivity and enhanced mechanical properties
Authors: Ren Liucheng , Ren Yanjuan , Zhang Yafei , Orzechowski Kazimierz , Kułacz Karol , Pocheć Michał , Bai Shu-Lin
Published: August 2020

Thermally conductive composites have attracted great attention in virtue of their crucial role in thermal management. In this work, laminated composites were prepared by laying graphite films (GF) and carbon fiber fabrics (CF) in a certain order, then penetrating thermoplastic polyurethane (TPU), finally hot-pressing. In order to enhance the inter-layer strength, the graphite films were perforated with arrays of 1 mm holes in diameter which have intervals of 4 mm and permit the seeping of liquid TPU through them. The in-plane thermal conductivity (TC) of composite reaches 242 W m−1 K−1 with the loading of 25 vol% GF and 60 vol% CF, which is 1210 times that of pure TPU. The great improvement of TC is ascribed to the thermal conductive pathways formed by continuous GF with ultrahigh TC. The addition of CF enhances markedly the mechanical properties of composites. Bending strength and modulus of composites are 5.56 and 17.09 times that of pure TPU, respectively. The proposed design and manufacture method are facile and effective to obtain polymeric composites simultaneously with high TC and good mechanical properties.
Shape control of piezoelectric bimorph by piezo response function and global optimization algorithms: a comparative study
Authors: Sumit  , Shukla Rahul , Sinha A K
Published: August 2020

In this paper shape control optimization of piezoelectric bimorph is done by piezo response function (PRF) and global optimization technique. PRF is used to formulate the optimization problem and global optimization algorithm is used to minimize the error between the target and the achieved shape. The performance of four global optimization techniques, simulated annealing (SA), genetic algorithm, particle swarm optimization and teacher learning based optimization are compared for the shape control of piezoelectric bimorph. 28 piezoelectric actuators are used in the piezoelectric bimorph to generate the sinusoidal profile, elliptical profile and arbitrary deformation profile by the external load. PRF is calculated by solving finite element model of piezoelectric bimorph and, optimization of electric potential with safety limit is done to achieve the target profiles by using all the aforementioned optimization techniques. SA gives best value of the objective function. At optimum electrode potential, the target and, achieved sinusoidal, elliptical and arbitrary deformation profiles obtained by SA at 5 × 107 computation, matches closely with root mean square (RMS) errors of 0.72, 12.18 and 28.86 nm, respectively. Subsequently, a robust and fully reproducible method for the shape control of piezo actuated deformable mirrors and smart structures is developed.
Guidance on Bayesian uncertainty evaluation for a class of GUM measurement models
Authors: Demeyer S , Fischer N , Elster C
Published: August 2020

In this paper we provide guidance on a Bayesian uncertainty evaluation for a large class of GUM measurement models covering linear and non-linear models. Bayesian analysis takes advantage of useful prior knowledge on the measurand, which is often available from a metrologist’s genuine expertise and opinion, or from previous experiments and which is neither taken into account by the GUM nor by its Supplement 1. For the considered class of measurement models, we establish the equivalence with the related statistical models and derive analytical expressions of the posterior distribution for an appropriate family of prior distributions, which allows one to gain insight into the result of the Bayesian uncertainty evaluation. We extend this work to the formulation of arbitrary prior distributions for the measurand and provide some guidance to set hyperparameter values within a class of priors based on elicitation techniques, so that the resulting priors reflect the prior knowledge. Posterior distributions are calculated by Markov Chain Monte Carlo methods. We apply the Bayesian uncertainty evaluation to the mass calibration example of Supplement 1 and compare our results with those obtained by the GUM and its Supplement 1. In order to study the impact of the choice of method for this example, we carry out a sensitivity analysis of the results with respect to the choice of prior. We show a virtually strong effect of the prior distribution which results in reduced uncertainty estimates for a small number of observations. When using noninformative priors, we obtain results comparable to those achieved by GUM-S1. Python code is made available that enables a Bayesian uncertainty evaluation also in other applications covered by the considered class of GUM measurement models.
Dynamics of interacting bubbles located in the center and vertices of regular polyhedra
Authors: Aganin I A , Davletshin A I
Published: August 2020

The dynamics of spherical gas bubbles located in the center and vertices of regular polyhedra under a sharp pressure increase in liquid is studied. Before the pressure rise, the liquid and the bubbles are at rest, the liquid pressure is 1 bar, the radii of the bubbles are 0.25 mm. The liquid pressure rises by 3 bar. For comparison, the configurations with one bubble in the center of a sphere and the others stochastically distributed inside it are also considered. In all the cases, the initial minimum distance between the centers of the bubbles does not exceed 5 mm. A mathematical model is used, in which the dynamics of the bubbles is governed by second-order ordinary differential equations in the radii of the bubbles and the position-vectors of their centers. It is shown that in all the bubble configurations considered, the amplitude of the pressure oscillations in the central bubble decreases nonmonotonically. With a sufficiently large number of peripheral bubbles, the change in the amplitude begins with a phase of its significant increase. With a rise in the number of the peripheral bubbles, the oscillation frequency of all bubbles decreases.
The influence of the capacitive coupled radio-frequency discharge on flax fiber
Authors: Aazanova A , Abutalipovaand L N , Khisamiyeva LG
Published: August 2020

The article presents the results of a study of the effect of radio-frequency (RF) capacitive plasma discharge at low pressure on flax textile fiber. The study object was a standard bleached and boiled flax yarn. In the considered modes, plasma treatment does not significantly affect the cellulosic component of flax fiber. However, the results of scanning electron microscopy showed signs of etching on the samples of bleached yarn. The results of x-ray diffraction demonstrated slight increase of the proportion of the crystalline phase. This is due to selective etching amorphous sections of the fibers surface. The results of determining the lignin content showed that it is relatively resistant to the action of RF plasma discharge and plays a protective role in relation to cellulose. However, damage (etching) of the fibers surface facilitates the rapid penetration of water into the fiber; therefore, lignin passes from fiber to aqueous solutions faster. The increase of the capillarity by 2–3 times, and the increase of the colourability and the breaking load of flax yarn by 25% are the technological effects of plasma processing of flax fiber (in the considered modes).
Wastewater disinfection methods
Authors: Akhatov M F , Kayumov R R , Valeeva R R , Mardanov R R
Published: August 2020

This article presents the results of experimental studies on wastewater disinfection using various methods. Proven use of ozone as an oxidizing agent is the most “clean” method compared to other methods.
Research of the influence of a hydrocarbon coating on the operational stability of membrane fabric
Authors: Vishnevskaya O V , Voznesensky E F , Vishnevsky V V , Shaekhov M F , Nizamova D K , Ahverdiev R F , Tihonova N V , Mahotkina L Y
Published: August 2020

The effect of the hydrocarbon coating on the operational stability of membrane tissues is investigated. Coating on membrane tissues was obtained by plasma-chemical vapor deposition of the products of polymerization and decomposition of acetylene. As a result, the resulting coating allows to: increase resistance to multi-cycle abrasive impact by 9,9-30,1%, while the resistance of the textile base to light, washing, dry and wet friction does not deteriorate; increase tensile strength by 5,7-13,4%; increase elongation to 11,0-18,4%. The stability of fixation of organosilicon impregnation in the structure of the textile base after modification in a nonequilibrium low-temperature plasma increases to 45,5%.
Determination of factors influencing the speed of moving arcs by rectanine electrodes
Authors: Gabdrakhmanov Az T , Israphilov I H , Galiakbarov A T , Gabdrakhmanova T F
Published: August 2020

A mathematical description of the gas motion in an electric discharge moving in the interelectrode gap under the action of the Lorentz force, considers in this paper. The presented model of the electric arc allows one to calculate the magnetic field acting on the charges in the discharge and to explain the occurrence of the arc shunting effect when moving along the electrodes.
Changes in the surface structure of nanostructured ceramics YBa2Cu3O7-y after exposure to a plasma stream
Authors: Gadzhimagomedov S Kh , Palchaev D K , Murlieva J Kh , Gadzhiev M Kh , Ragimkhanov G B , Demirov N A , Emirov R M , Rabadanova A E , Saypulaev P M
Published: August 2020

The paper presents the results of a study of the surface structure of nanostructured superconducting ceramics YBa2Cu3O7-y (YBCO) before and after short-term exposure to a plasma stream. Exposure to the plasma stream changes the structure of the ceramic surface and the oxygen content in it, and also slightly increases the average crystallite size.