bluuebunny/crossref_metadata_2025 huggingface dataset:
Network reconstruction of social networks based on the public information
Authors: Li Ren-De , Guo Qiang , Ma Hao-Tian , Liu Jian-Guo
Published: March 2021

The structure of a social network plays a crucial role for dynamic analysis, which is invisible in most scenes. In this paper, we present a model for reconstructing the social network by taking into account the public opinion diffusion dynamic model for specific agenda. First, the initial polarity attitude of users i for the agenda, oi, is set in the range [−1,1], where negative and positive attitudes are set as −1 and 1, respectively, while 0 means that user i’s attitude is uncertain. Second, we present an optimization model for detecting the relationship among each pair of users based on the generated public observable information. The experimental results for four synthetic networks and three real-world social networks show that the reconstruction accuracy depends on the uncertainty of the initial attitudes greatly. This work is helpful for revealing the structure of social networks in terms of public information.
Diffuse field cross-correlation in a programmable-metasurface-stirred reverberation chamber
Authors: del Hougne Philipp , Sol Jérôme , Mortessagne Fabrice , Kuhl Ulrich , Legrand Olivier , Besnier Philippe , Davy Matthieu
Published: March 2021

Programmable metasurfaces can endow complex scattering environments with reconfigurability. Here, we make use of these configurational degrees of freedom to retrieve the impulse response between two passive antennas via cross-correlation techniques. An ensemble of stirred chaotic wave fields in a reverberation chamber (RC) can play the role of thermal noise in passive Green's function retrieval. Instead of using a conventional mechanical mode stirrer, we generate the ensemble of RC configurations with random configurations of a programmable metasurface. We adapt the data processing of the diffuse field cross-correlation technique to this stirring mechanism, which is, given the size of the RC, nominally inefficient, and we investigate the convergence of the cross-correlated signals toward the impulse response. Finally, we apply our scheme to phaseless imaging in complex propagation environments, with potential applications in indoor context-awareness.
Coherent state transfer between superconducting qubits via stimulated Raman adiabatic passage
Authors: Li Danyu , Zheng Wen , Chu Ji , Yang Xiaopei , Song Shuqing , Han Zhikun , Dong Yuqian , Wang Zhimin , Yu Xiangmin , Lan Dong , Zhao Jie , Li Shaoxiong , Tan Xinsheng , Yu Yang
Published: March 2021

Coherent quantum state transfer is a vital step in quantum information processing. Based on the stimulated Raman adiabatic passage (STIRAP), we realize robust quantum state transfer between two superconducting qubits, mediated by a tunable coupler. Utilizing parametric coupling techniques, we construct the STIRAP Hamiltonian by modulating the coupler frequency. A population transfer fidelity of 95.1 (±2.0)% is achieved and is consistent with the numerical simulation result of 95.4%. By preparing the initial state in the maximal superposition state of one qubit, we research how the phase of the transferred state is related to the modulation pulses. We also find that the transfer process is robust against the fluctuation of modulation frequency. Numerical simulation confirms that our state transfer scheme is more robust than non-adiabatic protocols.
Structural and electronic properties of C60 fullerene network self-assembled on metal-covered semiconductor surfaces
Authors: Mihalyuk A. N. , Utas T. V. , Eremeev S. V. , Hsing C. R. , Wei C. M. , Zotov A. V. , Saranin A. A.
Published: March 2021

Using first-principles density functional theory calculations, we made an accurate structural characterization of the C60 superstructures self-assembled on the Tl-adsorbed Si(111) and Ge(111) surfaces, which finds a good agreement with the recent scanning tunneling microscopy observations. Our band structure calculations revealed the semi-metallic character of the C60/Tl/Si(111) system, while the C60/Tl/Ge(111) system was found to show up the pronounced metallic character due to the cascade of the flat bands lying in the vicinity of the Fermi level. The latter is a fingerprint for strong correlation effects in the C60/Tl/Ge(111) system, which makes it a promising object for studying electrical transport phenomena and opens the prospects for its application in the molecular-based electronic devices. We elucidated the details of the molecule–substrate and intermolecular interactions and discussed the character of a charge transfer in both systems.
A time-resolved, in-chamber x-ray pinhole imager for Z
Authors: Webb Timothy J. , Ampleford David , Ball Christopher R. , Gomez Matthew R. , Lake Patrick W. , Maurer Andrew , Presura Radu
Published: March 2021

We have commissioned a new time-resolved, x-ray imaging diagnostic for the Z facility. The primary intended application is for diagnosing the stagnation behavior of Magnetized Liner Inertial Fusion (MagLIF) and similar targets. We have a variety of imaging systems at Z, both time-integrated and time-resolved, that provide valuable x-ray imaging information, but no system at Z up to this time provides a combined high-resolution imaging with multi-frame time resolution; this new diagnostic, called TRICXI for Time Resolved In-Chamber X-ray Imager, is meant to provide time-resolved spatial imaging with high resolution. The multi-frame camera consists of a microchannel plate camera. A key component to achieving the design goals is to place the instrument inside the Z vacuum chamber within 2 m of the load, which necessitates a considerable amount of x-ray shielding as well as a specially designed, independent vacuum system. A demonstration of the imaging capability for a series of MagLIF shots is presented. Predictions are given for resolution and relative image irradiance to guide experimenters in choosing the desired configuration for their experiments.
Hyperuniform disordered distribution metasurface for scattering reduction
Authors: Zhang Haoyang , Cheng Qiao , Chu Hongchen , Christogeorgos Orestis , Wu Wen , Hao Yang
Published: March 2021

Metasurfaces with spatially varying reflection phases have promised great possibilities in realizing diffusion-like backward scattering. However, most studies in the field of metasurface reflectors focus on the diffusion generated by a phase gradient from unit cells in periodic grids. In this paper, we propose a general idea of integrating the concept of a hyperuniform disordered structure to realize a metasurface, where the effect of the spatial distribution is taken into account to realize more diffusion. A V-shaped structure is utilized as the unit cell for the metasurface to realize two kinds of elements with a phase difference of 180°. The metasurface is generated by distributing the unit cells according to a hyperuniform disordered distribution, and we compared its performance with a metasurface comprised of the same unit cells, distributed on a fixed periodic lattice. Both simulation and experimental results demonstrate that the metasurface with the hyperuniform disorder performs better than the periodic metasurface by enlarging the operating bandwidth with a significant reduction in the radar cross section of the surface. When the frequency operating frequency increases, only one reflected beam is observed for the metasurfaces based on hyperuniform disordered distribution, which is in contrast to the periodic metasurface where several multiple reflected beams are observed.
Compositional and phase dependence of elastic modulus of crystalline and amorphous Hf1-xZrxO2 thin films
Authors: Fields Shelby S. , Olson David H. , Jaszewski Samantha T. , Fancher Chris M. , Smith Sean W. , Dickie Diane A. , Esteves Giovanni , Henry M. David , Davids Paul S. , Hopkins Patrick E. , Ihlefeld Jon F.
Published: March 2021

The elastic moduli of amorphous and crystalline atomic layer-deposited Hf1-xZrxO2 (HZO, x = 0, 0.31, 0.46, 0.79, 1) films prepared with TaN electrodes on silicon substrates were investigated using picosecond acoustic measurements. The moduli of the amorphous films were observed to increase between 211 ± 6 GPa for pure HfO2 and 302 ± 9 GPa for pure ZrO2. In the crystalline films, it was found that the moduli increased upon increasing the zirconium composition from 248 ± 6 GPa for monoclinic HfO2 to 267 ± 9 GPa for tetragonal ZrO2. Positive deviations from this increase were observed for the Hf0.69Zr0.31O2 and Hf0.54Zr0.46O2 compositions, which were measured to have moduli of 264 ± 8 GPa and 274 ± 8 GPa, respectively. These two compositions contained the largest fractions of the ferroelectric orthorhombic phase, as assessed from polarization and diffraction data. The biaxial stress states of the crystalline films were characterized through sin2(ψ) x-ray diffraction analysis. The in-plane stresses were all found to be tensile and observed to increase with the increasing zirconium composition, between 2.54 ± 0.6 GPa for pure HfO2 and 5.22 ± 0.5 GPa for pure ZrO2. The stresses are consistent with large thermal expansion mismatches between the HZO films and silicon substrates. These results demonstrate a device-scale means to quantify biaxial stress for investigation on its effect on the ferroelectric properties of hafnia-based materials.
Greenhouse gas emissions and net ecosystem carbon budget from tobacco-planted soil with different organic amendments
Authors: Yao Pengwei , Pan Haodong , Qin Yihe , Zhang Zhen , Wang Jing , Li Xueli , Liu Xiaoping , Wang Peng , Ye Xiefeng
Published: March 2021

Inputs of organic materials are recommended to increase soil carbon (C) sequestration and crop growth. However, organic amendments may increase greenhouse gas (GHG) emissions. To comprehensively evaluate the effect of organic amendments on the net ecosystem C budget (NECB) and net global warming potential (net GWP) in a successive tobacco cultivation system, methane (CH4) and nitrous oxide (N2O) fluxes and main components of the NECB under different treatments were measured in a pot experiment. The experiment with cultivated tobacco plants included five treatments: no fertiliser (NF), NPK, NPK plus wheat straw, NPK plus sesame cake (NPKC) and NPK plus biochar made from tobacco stalks. The results of NECB and estimated SOC changes implied that the tobacco-cultivated ecosystems acted as a C source under the NF, NPK and NPKC treatments, whereas the systems acted as a C sink with the application of straw and biochar. N2O emissions were significantly increased by 53.7% and 96.2% in soils amended with straw and sesame cake respectively. Biochar addition had no effect on N2O emissions. CH4 uptake was not affected by organic amendments. As a result, the application of straw and biochar significantly decreased the net GWP and GHG intensity, but sesame cake amendments had no such significant effects. Therefore, in comparison to the other treatments, the straw and biochar treatments were more effective GHG mitigation practices that increased the yield and NECB in the tobacco cultivation system, and this was especially true for the biochar treatment.
CD47 blockade reduces the pathologic features of experimental cerebral malaria and promotes survival of hosts with
Plasmodium
infection
Authors: Torrez Dulgeroff Laughing Bear , Oakley Miranda S. , Tal Michal C. , Yiu Ying Ying , He Joy Q. , Shoham Maia , Majam Victoria , Okoth Winter A. , Malla Pallavi , Kumar Sanjai , Weissman Irving L.
Published: March 2021

Significance

Novel therapies are urgently needed that can ameliorate the clinical syndromes of cerebral malaria, the most severe consequences of
Plasmodium
infection, and thereby reduce malaria fatality. Monoclonal antibodies that target CD47, a “don’t eat me” signal, have been demonstrated to enhance cellular clearance of cancer cells by promoting macrophage phagocytosis. We sought to adopt this therapeutic strategy to ameliorate the clinical syndromes associated with cerebral malaria with the goals of reducing disease-associated morbidity and mortality. We demonstrate that CD47 blockade by anti-CD47 injection leads to survival from cerebral malaria in mice.
A functional screen identifies transcriptional networks that regulate HIV-1 and HIV-2
Authors: Pedro Kyle D. , Agosto Luis M. , Sewell Jared A. , Eberenz Kimberly A. , He Xianbao , Fuxman Bass Juan I. , Henderson Andrew J.
Published: March 2021

Significance

Understanding mechanisms that control HIV expression will provide insight into HIV replication, latency, and pathogenesis. In particular, HIV latency, which is a major barrier to a cure, is maintained by combinatorial mechanisms that regulate transcription. A functional screen was employed to explore transcriptional networks that regulate HIV. These studies identified novel transcription factors that influence HIV transcription and provided an appreciation into intrinsic networks that influence transcriptional activation and repression of different HIV strains.
Antigenic cartography reveals complexities of genetic determinants that lead to antigenic differences among pandemic GII.4 noroviruses
Authors: Kendra Joseph A. , Tohma Kentaro , Ford-Siltz Lauren A. , Lepore Cara J. , Parra Gabriel I.
Published: March 2021

Significance

The GII.4 genotype of human noroviruses accounts for the majority of gastroenteritis outbreaks worldwide. This predominance is characterized by the chronological emergence of new variants in response to immune pressure. We performed a comprehensive analysis on a large panel of GII.4 viruses to investigate the genetic determinants of antigenic diversification. Using immunoassays and neutralization data, we observed major changes to antigenic properties over the course of GII.4 evolution and increased intervariant cross-reactivity across contemporary viruses. Antigenic cartography and sequence analyses indicated a minimum number of coevolving amino acid changes on the structural protein necessary for the emergence of antigenically distinct variants. These insights could facilitate the monitoring and characterization of emerging GII.4 noroviruses and the development of cross-protective vaccines.
Chloride-dependent conformational changes in the GlyT1 glycine transporter
Authors: Zhang Yuan-Wei , Uchendu Stacy , Leone Vanessa , Bradshaw Richard T. , Sangwa Ntumba , Forrest Lucy R. , Rudnick Gary
Published: March 2021

Significance

The NSS (neurotransmitter sodium symporter) or SLC6 family comprises a group of plasma membrane transport proteins that includes transporters for amino acid and amine neurotransmitters. Transporters in this family use transmembrane ion gradients as driving forces for intracellular accumulation of their substrates. Although all NSS transporters use Na
+
ions for transport, a large subset also requires Cl
−
ions. Na
+
is known to act at two sites on these proteins to stabilize an outward-open conformation and to interact with substrate to facilitate transition to an inward-open conformation, but the role of Cl
−
has not previously been established. We show here how Cl
−
acts independently from substrate to facilitate the conversion of an NSS transporter for glycine from outward- to inward-open states.
Cadherin cis and trans interactions are mutually cooperative
Authors: Thompson Connor J. , Vu Vinh H. , Leckband Deborah E. , Schwartz Daniel K.
Published: March 2021

Significance

Cadherin-mediated intercellular adhesion involves both cis and trans interactions between cadherin extracellular domains. It has been hypothesized that the combination of these cis and trans interactions is critical for the formation of macroscopic adhesions. Here, we have used single-molecule microscopy to show that cis and trans interactions are mutually cooperative, in that cis interactions directly increase the stability of trans bonds and trans interactions similarly increase the stability of cis bonds. Furthermore, we show that this cooperativity directly results in cadherin accumulation to form macroscopic intermembrane junctions. This cooperativity occurs at the molecular level and suggests that trans dimers are allosterically stabilized by individual cis interactions. These results provide mechanistic insight into cadherin junction assembly, independent of cytoplasmic interactions.
Neuromechanical wave resonance in jellyfish swimming
Authors: Hoover Alexander P. , Xu Nicole W. , Gemmell Brad J. , Colin Sean P. , Costello John H. , Dabiri John O. , Miller Laura A.
Published: March 2021

Significance

Despite a relatively simple nervous system, jellyfish manage a broad range of motion from a distributed set of pacemakers, which initiate action potentials that form a wave of muscular activation to drive the bell motion. In this interdisciplinary study, we find that successful turning maneuvers are dependent on the speed of this activation wave. Using a three-dimensional computational fluid–structure interaction model, we demonstrate that setting the activation wave speed near the bell’s material wave speed, from the elastic wave equation, yields the strongest turning and margin hyperextension. This suggests an undescribed neuromechanical constraint on the bell, an important finding pertinent to the actuation of biomimetic vehicles and tissue-engineered pumps, as well as the biology of locomotion in flexible animals.
Cryo-EM structure and kinetics reveal electron transfer by 2D diffusion of cytochrome
c
in the yeast III-IV respiratory supercomplex
Authors: Moe Agnes , Di Trani Justin , Rubinstein John L. , Brzezinski Peter
Published: March 2021

Significance

In the last steps of food oxidation in living organisms, electrons are transferred to oxygen through the membrane-bound respiratory chain. This electron transfer is mediated by mobile carriers, such as membrane-bound quinone and water-soluble cytochrome
c
. The latter transfers electrons from respiratory complex III to complex IV. In yeast, these complexes assemble into III
2
IV
1/2
supercomplexes, but its role has remained enigmatic. This study establishes a functional role for this supramolecular assembly in the mitochondrial membrane. We used cryo-EM and kinetic studies to show that cytochrome
c
shuttles electrons by two-dimensional diffusion, sliding along the surface of III
2
IV
1/2
. The structural arrangement of III
2
IV
1/2
supercomplexes suggests a mechanism to regulate cellular respiration.
Emergent robustness of bacterial quorum sensing in fluid flow
Authors: Dalwadi Mohit P. , Pearce Philip
Published: March 2021

Significance

Bacteria control multicellular behaviors through a process called quorum sensing (QS). Because QS signaling molecules diffuse between cells, they are susceptible to removal by external fluid flow, which is a ubiquitous feature of bacterial habitats ranging from the lungs, gut, and nasal passage to rivers, lakes, and oceans. It is therefore vital to account for realistic flow conditions when assessing the functional role of QS genetic networks. By systematically connecting cell- and population-level processes, our theory demonstrates and quantifies how positive feedback in QS networks allows bacterial populations to overcome spatiotemporal chemical gradients caused by steady or intermittent external fluid flow and to orchestrate robust collective responses in complex environments.
Ultrafast nanometric imaging of energy flow within and between single carbon dots
Authors: Nguyen Huy A. , Srivastava Indrajit , Pan Dipanjan , Gruebele Martin
Published: March 2021

Significance

Carbon dots are promising fluorescent nanomaterials, but their fluorescence yield is fairly low when measured in the bulk. By observing single dots directly using femtosecond single-nanometer resolution imaging, we find that some carbon dots fluoresce exceedingly well and others not at all. We propose a simple mechanism, which suggests that near-perfect fluorescence yield is possible by improved separation or synthesis, as indeed quantum yields of carbon dots have been improving.
Theory of bulk photovoltaic effect in Anderson insulator
Authors: Ishizuka Hiroaki , Nagaosa Naoto
Published: March 2021

Significance

Localization and its effect on electronic transport is a key for understanding the properties of disordered systems. In this work, we theoretically study the bulk photovoltaic effect in Anderson insulators, which occurs when a weak dissipation exists. Despite the localization of all wavefunctions, the photocurrent is nearly independent of the impurity strength when it is smaller than the bandwidth. This current vanishes in the absence of dissipation, while it reaches a value comparable to that of the clean limit with a dissipation expected at room temperature, assuming electron–phonon interaction causes the dissipation. These results are consistent with a recent experiment in SbSI. The results open a direction for designing efficient optical devices with a suppressed carrier backflow.
Ki-67 regulates global gene expression and promotes sequential stages of carcinogenesis
Authors: Mrouj Karim , Andrés-Sánchez Nuria , Dubra Geronimo , Singh Priyanka , Sobecki Michal , Chahar Dhanvantri , Al Ghoul Emile , Aznar Ana Bella , Prieto Susana , Pirot Nelly , Bernex Florence , Bordignon Benoit , Hassen-Khodja Cedric , Villalba Martin , Krasinska Liliana , Fisher Daniel
Published: March 2021

Significance

Ki-67 is a nuclear protein present in all proliferating vertebrate cells and is widely used as a marker in clinical cancer histopathology. However, its cellular functions have remained largely mysterious, and whether it plays any roles in cancer was unknown. In this work, we show genetically that Ki-67 is not required for cell proliferation in tumors, but it is required for all stages of carcinogenesis. The effects on cell transformation, tumor growth, metastasis, and drug sensitivity correlate with genome-scale changes in gene expression that modify cellular programs implicated in cancer. Thus, Ki-67 expression is advantageous for cancer cells, but it comes with an Achilles’ heel: it makes them more visible to the immune system.
Signs and words
Authors: Sandler Wendy
Published: March 2021

Natural sign languages both constrain and expand
our understanding of the nature of words. In each modality, words
can be used in isolation, have meanings or grammatical functions,
and are identifiable by their prosodic form. Such shared properties
constrain the universal definition of the word. The differences,
such as pervasive simultaneity and iconicity in sign word structure
and word formation, compared to linearity and arbitrariness typical
of spoken words, expand our conception of what a word can be.
Investigation of an emerging sign language reveals just how
fundamental the word is to language, and shows how morphological
complexity begins as an abstract pattern. Sign languages introduce a
tension between constraining and expanding the definitive properties
of words, offering a more nuanced understanding of this most basic
unit of linguistic structure.
Multi-layered default in Ripano
Authors: Loporcaro Michele , Paciaroni Tania
Published: March 2021

This chapter deals with morphological and
syntactic defaults in Ripano (Italo-Romance), using the toolkit of
Network Morphology and Canonical Typology. Analyzing noun and
adjective inflection, we propose a unitary inheritance hierarchy for
nominals which features a general default plus overrides specifying
class-specific rules of exponence. The hierarchy accounts for gender
assignment along with inflectional classes, as Ripano has
overwhelmingly overt gender. This also offers the link to the
syntax, because in Ripano overt gender is not context-free but
depends on syntactic context, a property never described for any
other language of the world. We show that one can distinguish a
normal vs an exceptional-case default and conclude on how these
relate to the morphological default established in the inheritance
hierarchy.
COVID-19: A Catalyst for Change in Telehealth Service Delivery for Opioid use Disorder Management
Authors: Mehtani Nicky J. , Ristau Jessica T. , Snyder Hannah , Surlyn Colleen , Eveland Joanna , Smith-Bernardin Shannon , Knight Kelly R.
Published: March 2021

Background

COVID-19 has exacerbated income inequality, structural racism, and social isolation—issues that drive addiction and have previously manifested in the epidemic of opioid-associated overdose. The co-existence of these epidemics has necessitated care practice changes, including the use of telehealth-based encounters for the diagnosis and management of opioid use disorder (OUD).

Methods

We describe the development of the “Addiction Telehealth Program” (ATP), a telephone-based program to reduce treatment access barriers for people with substance use disorders staying at San Francisco's COVID-19 Isolation and Quarantine (I&Q) sites. Telehealth encounters were documented in the electronic medical record and an internal tracking system for the San Francisco Department of Public Health (SFDPH) COVID-19 Containment Response. Descriptive statistics were collected on a case series of patients initiated on buprenorphine at I&Q sites and indicators of feasibility were measured.

Results

Between April 10 and May 25, 2020, ATP consulted on the management of opioid, alcohol, GHB, marijuana, and stimulant use for 59 I&Q site guests. Twelve patients were identified with untreated OUD and newly prescribed buprenorphine. Of these, all were marginally housed, 67% were Black, and 58% had never previously been prescribed medications for OUD. Four self-directed early discharge from I&Q—1 prior to and 3 after initiating buprenorphine. Of the remaining 8 patients, 7 reported continuing to take buprenorphine at the time of I&Q discharge and 1 discontinued. No patients started on buprenorphine sustained significant adverse effects, required emergency care, or experienced overdose.

Conclusions

ATP demonstrates the feasibility of telephone-based management of OUD among a highly marginalized patient population in San Francisco and supports the implementation of similar programs in areas of the U.S. where access to addiction treatment is limited. Legal changes permitting the prescribing of buprenorphine via telehealth without the requirement of an in-person visit should persist beyond the COVID-19 public health emergency.
Adverse Childhood Experiences and the Onset of Aggression and Criminality in a Forensic Inpatient Sample
Authors: Stinson Jill D. , Quinn Megan A. , Menditto Anthony A. , LeMay Carrie C.
Published: March 2021

Offenders and persons with serious mental illness experience disproportionate exposure to Adverse Childhood Experiences (ACEs). This study examines prevalence, distribution, and correlates of ACEs in 182 male and female forensic psychiatric inpatients in secure care. Descriptive statistics, chi-squares analysis, ANOVA, and logistic regression were used to describe ACEs by race and gender and to identify associations between ACEs and onset of aggression, arrest, and psychiatric hospitalization. Participants evidenced significant exposure to ACEs, with significant differences by race and gender. ACE score, race, and foster care or investigations of child abuse were significant predictors of outcomes related to aggression and criminality.
Plasmodium falciparum–specific IgM B cells dominate in children, expand with malaria, and produce functional IgM
Authors: Hopp Christine S. , Sekar Padmapriya , Diouf Ababacar , Miura Kazutoyo , Boswell Kristin , Skinner Jeff , Tipton Christopher M. , Peterson Mary E. , Chambers Michael J. , Andrews Sarah , Lu Jinghua , Tan Joshua , Li Shanping , Doumbo Safiatou , Kayentao Kassoum , Ongoiba Aissata , Traore Boubacar , Portugal Silvia , Sun Peter D. , Long Carole , Koup Richard A. , Long Eric O. , McDermott Adrian B. , Crompton Peter D.
Published: March 2021

IgG antibodies play a role in malaria immunity, but whether and how IgM protects from malaria and the biology of Plasmodium falciparum (Pf)–specific IgM B cells is unclear. In a Mali cohort spanning infants to adults, we conducted longitudinal analyses of Pf- and influenza-specific B cells. We found that Pf-specific memory B cells (MBCs) are disproportionally IgM+ and only gradually shift to IgG+ with age, in contrast to influenza-specific MBCs that are predominantly IgG+ from infancy to adulthood. B cell receptor analysis showed Pf-specific IgM MBCs are somatically hypermutated at levels comparable to influenza-specific IgG B cells. During acute malaria, Pf-specific IgM B cells expand and upregulate activation/costimulatory markers. Finally, plasma IgM was comparable to IgG in inhibiting Pf growth and enhancing phagocytosis of Pf by monocytes in vitro. Thus, somatically hypermutated Pf-specific IgM MBCs dominate in children, expand and activate during malaria, and produce IgM that inhibits Pf through neutralization and opsonic phagocytosis.
Multimeric antibodies from antigen-specific human IgM+ memory B cells restrict Plasmodium parasites
Authors: Thouvenel Christopher D. , Fontana Mary F. , Netland Jason , Krishnamurty Akshay T. , Takehara Kennidy K. , Chen Yu , Singh Suruchi , Miura Kazutoyo , Keitany Gladys J. , Lynch Eric M. , Portugal Silvia , Miranda Marcos C. , King Neil P. , Kollman Justin M. , Crompton Peter D. , Long Carole A. , Pancera Marie , Rawlings David J. , Pepper Marion
Published: March 2021

Multimeric immunoglobulin-like molecules arose early in vertebrate evolution, yet the unique contributions of multimeric IgM antibodies to infection control are not well understood. This is partially due to the difficulty of distinguishing low-affinity IgM, secreted rapidly by plasmablasts, from high-affinity antibodies derived from later-arising memory cells. We developed a pipeline to express B cell receptors (BCRs) from Plasmodium falciparum–specific IgM+ and IgG+ human memory B cells (MBCs) as both IgM and IgG molecules. BCRs from both subsets were somatically hypermutated and exhibited comparable monomeric affinity. Crystallization of one IgM+ MBC-derived antibody complexed with antigen defined a linear epitope within a conserved Plasmodium protein. In its physiological multimeric state, this antibody displayed exponentially higher antigen binding than a clonally identical IgG monomer, and more effectively inhibited P. falciparum invasion. Forced multimerization of this IgG significantly improved both antigen binding and parasite restriction, underscoring how avidity can alter antibody function. This work demonstrates the potential of high-avidity IgM in both therapeutics and vaccines.
MICROSCOPE. mission analysis, requirements and expected performance
Authors: Touboul Pierre , Rodrigues Manuel , Métris Gilles , Chhun Ratana , Robert Alain , Baghi Quentin , Hardy Emilie , Bergé Joel , Boulanger Damien , Christophe Bruno , Cipolla Valerio , Foulon Bernard , Guidotti Pierre-Yves , Huynh Phuong-Anh , Lebat Vincent , Liorzou Françoise , Pouilloux Benjamin , Prieur Pascal , Reynaud Serge
Published: March 2021

The MICROSCOPE mission aimed to test the weak equivalence principle (WEP) to a precision of 10−15. The WEP states that two bodies fall at the same rate on a gravitational field independently of their mass or composition. In MICROSCOPE, two masses of different compositions (titanium and platinum alloys) are placed on a quasi-circular trajectory around the Earth. They are the test-masses of a double accelerometer. The measurement of their accelerations is used to extract a potential WEP violation that would occur at a frequency defined by the motion and attitude of the satellite around the Earth. This paper details the major drivers of the mission leading to the specification of the major subsystems (satellite, ground segment, instrument, orbit…). Building upon the measurement equation, we derive the objective of the test in statistical and systematic error allocation and provide the mission’s expected error budget.
The Fourier–Bessel expansion: application to experimental probes of gravity and feeble short-range interactions
Authors: Lee J G , Adelberger E G , Marcoline F V , Terrano W A , Heckel B R
Published: March 2021

Two Eöt–Wash torsion balance instruments exploited optimized Fourier–Bessel geometries to test the short-distance properties of gravity and to constrain exotic dipole–dipole and monopole–dipole interactions. We discuss efficient analytic techniques for computing the expected torques in those instruments arising from Newtonian and Yukawa interactions between unpolarized test bodies and dipole–dipole and monopole–dipole torques on polarized test-bodies. We consider systematic effects induced by weak external magnetic fields on the nominally unpolarized test-bodies. We also present a new Fourier–Bessel expansion for inverse-power-law (IPL) potentials and use this to calculate the expected IPL signals in our recent short-distance test of the gravitational inverse-square law. Our results slightly improve limits on inverse-5th-power law potentials.
Electron impact single ionization differential cross sections of W (6s), W (5d), W (5p) and W (4f)
Authors: Purohit G
Published: March 2021

Electron-induced triple differential cross sections (TDCSs) have been obtained for the few outer sub-shells of tungsten atoms, namely W (6s), W (5d), W (5p) and W (4f). Tungsten and related materials have been recommended as the prime candidates for wall materials in fusion plasma devices. The electron-induced cross-section data are strongly required for the diagnostics and modeling of plasma in such devices. We observe that the trends of TDCSs obtained for the ionization of W (5d) sub-shells are very different from the TDCSs of W (6s), W (5p) and W (4f) in terms of binary and recoil peak locations as well as in the change of magnitude of TDCS with an increasing value of momentum transfer which is due to the open d-shell. The angle and energy-resolved cross-section data of tungsten atoms may be of vital importance in order to understand the spectroscopy of W atoms as wall materials as well as an impurity.
Squeezed light generation in cascaded optomechanical systems
Authors: Wang Yue-Yuan , Yi Zhen , Yan Yan , Gu Wen-Ju
Published: March 2021

We theoretically investigate the enhancement of the degree and bandwidth of squeezed states of light generated in cascaded optomechanical (OM) systems. With the obtained recursion relation of the generalized output quadratures, it is possible to realize cascaded OM systems operated simultaneously in a deamplification situation for the same quadrature with a frequency-dependent phase shift between cascaded systems. Due to the cumulative OM interaction, the degree of squeezing can be significantly improved and nearly independent of frequencies. Thus the squeezing frequency band is notably broadened. Moreover, the squeezing bandwidth can be further broadened through tuning the detunings between laser and cavity frequencies. Finally, the influence of optical losses on squeezing due to the inefficient transmission between cascaded systems is also taken into account, which degrades the squeezing via introducing uncorrelated vacuum noises. However, a better squeezed state is still achievable compared to that generated in single OM system.
First-principles study of ultrafast dynamics of Dirac plasmon in graphene
Authors: Novko Dino
Published: March 2021

Exploring low-loss two-dimensional plasmon modes is considered central for achieving light manipulation at the nanoscale and applications in plasmonic science and technology. In this context, pump–probe spectroscopy is a powerful tool for investigating these collective modes and the corresponding energy transfer processes. Here, I present a first-principles study on non-equilibrium Dirac plasmon in graphene, wherein damping channels under ultrafast conditions are still not fully explored. The laser-induced blueshift of plasmon energy is explained in terms of thermal increase of the electron–hole pair concentration in the intraband channel. Interestingly, while damping pathways of the equilibrium graphene plasmon are entirely ruled by scatterings with acoustic phonons, the photoinduced plasmon predominantly transfers its energy to the strongly coupled hot optical phonons, which explains the experimentally-observed tenfold increase of the plasmon linewidth. The present study paves the way for an in-depth theoretical comprehension of plasmon temporal dynamics in novel two-dimensional systems and heterostructures.
Fission fragment mass yields of Th to Rf even-even nuclei *
Authors: Pomorski Krzysztof , Blanco José M. , Kostryukov Pavel V. , Dobrowolski Artur , Nerlo-Pomorska Bożena , Warda Michał , Xiao Zhi-Gang , Chen Yong-Jing , Liu Li-Le , Tian Jun-Long , Diao Xin-Yue , Wu Qiang-Hua
Published: March 2021

Fission properties of the actinide nuclei are deduced from theoretical analysis. We investigate potential energy surfaces and fission barriers and predict the fission fragment mass yields of actinide isotopes. The results are compared with experimental data where available. The calculations were performed in the macroscopic-microscopic approximation with the Lublin-Strasbourg Drop (LSD) for the macroscopic part, and the microscopic energy corrections were evaluated in the Yukawa-folded potential. The Fourier nuclear shape parametrization is used to describe the nuclear shape, including the non-axial degree of freedom. The fission fragment mass yields of the nuclei considered are evaluated within a 3D collective model using the Born-Oppenheimer approximation.
Neural activity shaping utilizing a partitioned target pattern
Authors: Spencer Martin J , Kameneva Tatiana , Grayden David B , Burkitt Anthony N , Meffin Hamish
Published: March 2021

Electrical stimulation of neural tissue is used in both clinical and experimental devices to evoke a desired spatiotemporal pattern of neural activity. These devices induce a local field that drives neural activation, referred to as an activating function or generator signal. In visual prostheses, the spread of generator signal from each electrode within the neural tissue results in a spread of visual perception, referred to as a phosphene. Objective. In cases where neighbouring phosphenes overlap, it is desirable to use current steering or neural activity shaping strategies to manipulate the generator signal between the electrodes to provide greater control over the total pattern of neural activity. Applying opposite generator signal polarities in neighbouring regions of the retina forces the generator signal to pass through zero at an intermediate point, thus inducing low neural activity that may be perceived as a high-contrast line. This approach provides a form of high contrast visual perception, but it requires partitioning of the target pattern into those regions that use positive or negative generator signals. This discrete optimization is an NP-hard problem that is subject to being trapped in detrimental local minima. Approach. This investigation proposes a new partitioning method using image segmentation to determine the most beneficial positive and negative generator signal regions. Utilizing a database of 1000 natural images, the method is compared to alternative approaches based upon the mean squared error of the outcome. Main results.
Under nominal conditions and with a set computation limit, partitioning provided improvement for 32% of these images. This percentage increased to 89% when utilizing image pre-processing to emphasize perceptual features of the images. The percentage of images that were dealt with most effectively with image segmentation increased as lower computation limits were imposed on the algorithms. Significance. These results provide a new method to increase the resolution of neural stimulating arrays and thus improve the experience of visual prosthesis users.
Inferring functional connectivity through graphical directed information
Authors: Young Joseph , Neveu Curtis L , Byrne John H , Aazhang Behnaam
Published: March 2021

Objective. Accurate inference of functional connectivity is critical for understanding brain function. Previous methods have limited ability distinguishing between direct and indirect connections because of inadequate scaling with dimensionality. This poor scaling performance reduces the number of nodes that can be included in conditioning. Our goal was to provide a technique that scales better and thereby enables minimization of indirect connections. Approach. Our major contribution is a powerful model-free framework, graphical directed information (GDI), that enables pairwise directed functional connections to be conditioned on the activity of substantially more nodes in a network, producing a more accurate graph of functional connectivity that reduces indirect connections. The key technology enabling this advancement is a recent advance in the estimation of mutual information (MI), which relies on multilayer perceptrons and exploiting an alternative representation of the Kullback–Leibler divergence definition of MI. Our second major contribution is the application of this technique to both discretely valued and continuously valued time series. Main results. GDI correctly inferred the circuitry of arbitrary Gaussian, nonlinear, and conductance-based networks. Furthermore, GDI inferred many of the connections of a model of a central pattern generator circuit in Aplysia, while also reducing many indirect connections. Significance. GDI is a general and model-free technique that can be used on a variety of scales and data types to provide accurate direct connectivity graphs and addresses the critical issue of indirect connections in neural data analysis.
Thermographic reconstruction of heat load on the first wall of Wendelstein 7-X due to ECRH shine-through power
Authors: Corre Y. , Gaspar J. , Marsen S. , Moseev D. , Stange T. , Boscary J. , Drewelow P. , Gao Y. , Jakubowski M. , Hillairet J. , Laqua H.P. , Lechte C. , Moncada V. , Niemann H. , Preynas M. , Puig Sitjes A.
Published: March 2021

Electron cyclotron resonance heating (ECRH) is a powerful and flexible plasma heating technique that serves as the main heater at Wendelstein 7-X (W7-X) and will be used at ITER for start-up, heating, current drive and mitigation of plasma instabilities. In the case of poor or degraded microwave absorption, which is expected in the O2-mode heating scenario, a significant part of the beam directly hits the wall, leading to local overheating and potential damage. The ECRH shine-through power is mostly reflected onto the targets; only a small fraction is really absorbed through ohmic losses (typically 3% for graphite at 140 GHz). The ohmic losses do not only depend on the material properties and the frequency, but also on the polarization of the wave and the angle of incidence. This paper presents a thermographic analysis of ECRH experiments at W7-X, including heat load and temperature simulations of the first wall that include ECRH shine through. Two O-mode ECRH experiments with both a high temperature rise of the first wall and different angles of beam incidence on the wall’s surface are depicted. One experiment has 775 kW of power modulation (5 Hz) with mixed polarization (45% O-mode, 55% X-mode) and an EC beam angle almost normal to the first wall. The second has 550 kW of steady EC power with O-mode polarization, a shallow beam angle and increased power absorption by the material. It is shown that infrared thermography is a useful tool for measuring shine-through power and protecting wall components.
I-mode in non-deuterium plasmas in ASDEX Upgrade
Authors: Bonanomi N. , Angioni C. , Silvagni D. , Happel T. , Plank U. , Gil L. , Schneider P.A. , Puetterich T. , EUROFusion MST1 Team the , ASDEX Upgrade Team the
Published: March 2021

The I-mode confinement regime in non-deuterium plasmas has been investigated in the ASDEX Upgrade tokamak. We report the first experimental observations on the existence and the main characteristics of this regime in hydrogen and helium plasmas and compare them with deuterium I-modes. Hydrogen features a higher power threshold to enter I-mode and a higher electron edge pressure at the L- to I-mode transition with respect to deuterium. Furthermore, all the hydrogen I-modes obtained exhibit pedestal relaxation events (PRE). The I-mode power window in hydrogen is found to be 2–3 times larger than in deuterium. This property allows a better characterization of PRE and to differentiate them from type-III ELMs. Helium I-modes feature properties which are similar to those of deuterium I-modes. The analysis on the minimum of the edge radial electric field E
r shows a correlation between the E
r minimum, the net input power and the ion diamagnetic term in the ion radial force balance. Indications of the dominant role of the edge ion temperature in the evolution of the radial electric field with increasing input power are also reported.
Testing predictions of electron scale turbulent pedestal transport in two DIII-D ELMy H-modes
Authors: Guttenfelder W. , Groebner R.J. , Canik J.M. , Grierson B.A. , Belli E.A. , Candy J.
Published: March 2021

In this paper, we present linear and nonlinear gyrokinetic analyses in the pedestal region of two DIII-D ELMy H-mode discharges using the CGYRO code. The otherwise matched discharges employ different divertor configurations to investigate the impact of varying recycling and particle source on pedestal profiles. Linear gyrokinetic simulations find electrostatic ion-scale instabilities (ion temperature gradient and trapped electron modes, ITG–TEM) are present just inside the top of the pedestal with growth rates that are enhanced significantly by parallel velocity shear. In the sharp gradient region, E × B shearing rates are comparable or larger than ion scale growth rates, suggesting the suppression of ITG–TEM modes in this region. Instead, the electron temperature profiles are found to be correlated with and just above the electron temperature gradient (ETG) instability thresholds. Using gradients varied within experimental uncertainties, nonlinear electron-scale gyrokinetic simulations predict electron heat fluxes from ETG turbulence, that when added to neoclassical (NC) ion thermal transport simulated by NEO, account for 30%–60% of the total experimental heat flux. In addition, the NC electron particle flux is found to contribute significantly to the experimental fluxes inferred from SOLPS-ITER analysis. Additional nonlinear gyrokinetic simulations are run varying input gradients to develop a threshold-based reduced model for ETG transport, finding a relatively simple dependence on η
e = L
ne/L
Te. Predictive transport simulations are used to validate this pedestal-specific ETG model, in conjunction with a model for NC particle transport. In both discharges, the predicted electron temperatures are always overpredicted, indicative of the insufficient stiffness in the ETG pedestal model to account for all of the experimental electron thermal transport. In the case of the closed divertor discharge with lower particle source, the predicted electron density is close to the experiment, consistent with the magnitude of NC particle transport in that discharge. However, the density profiles are overpredicted in the open divertor discharge (larger particle source), due to insufficient model transport. The implications for other mechanisms accounting for the remainder of transport in the sharp gradient region in the two discharges are discussed.