bluuebunny/crossref_metadata_2025 huggingface dataset:
Metagenomics analysis of mice gut microbiome to unravel the role of metal exposure and piperine
Authors: Kaur Ravidarshdeep , Singh Dhirendra Pratap , Rawal Rakesh
Published: February 2024

The gut and intestinal microbiota consists of trillions of microorganisms inhabiting the human gastrointestinal tract. It plays a crucial role in human health leading to understanding the dynamic crosstalk of host-microbe interaction in the gut and has become necessary for the detection, prevention, or therapy of diseases. Gut microbiota deviations are linked with many diseases, suggesting that various pathways involved in immunity, energy, lipid, and glucose metabolism are affected. Further, it is also altered by external insults such as metal toxicity, antibiotics and pesticides. Heavy metals like arsenic, mercury, cadmium and chromium are some of the well-studied classes of environmental pollutants. Mouse models have become the model of choice for most studies in this emerging field, as they allow perturbations in the gut microbiota to be studied in a controlled experimental setup. Here, we investigate the composition and diversity of intestinal microbes utilizing cecal samples from different intervention groups: arsenic exposure (As(III)), arsenic and piperine co-administration (As +Pp), piperine per se and control group. We obtained DNA samples from these groups and performed PCR amplification and sequencing of the 16S V3-V4 region. The findings showed shift in microbial composition and abundance among different intervention groups, revealing taxa that may contribute to the microbial diversity.
Judicial Opinion 129
Authors: Arahal David R. , Bull Carolee T. , Christensen Henrik , Chuvochina Maria , Dedysh Svetlana N. , Fournier Pierre-Edouard , Konstantinidis Konstantinos T. , Parker Charles T. , Ventosa Antonio , Young Peter , Göker Markus
Published: February 2024

Opinion 129 addresses the status of Firmicutes corrig. Gibbons and Murray 1978 (Approved Lists 1980). The name has the category ‘division’ and was included in the Approved Lists of Bacterial Names, although that category had previously been removed from the International Code of Nomenclature of Bacteria (1975 revision onwards). When the category ‘phylum’ was introduced into the International Code of Nomenclature of Prokaryotes (ICNP) in 2021, equivalence between ‘phylum’ and ‘division’ was not stipulated. Since the definition of the taxonomic categories and their relative order is one of the principal tasks of every code of nomenclature, the inclusion of Firmicutes corrig. Gibbons and Murray 1978 in the Approved Lists was an error. The name is either not validly published or illegitimate because its category is not covered by the ICNP. If Firmicutes corrig. Gibbons and Murray 1978 (Approved Lists 1980) was a validly published phylum name, it would be illegitimate because it would contravene Rule 8, which does not permit any deviation from the requirement to derive a phylum name from the name of the type genus. Since Firmicutes corrig. Gibbons and Murray 1978 is also part of a ‘misfitting megaclassification’ recognized in Opinion 128, the name is rejected, without any pre-emption regarding a hypothetically validly published name Firmicutes at the rank of phylum. Gracilicutes Gibbons and Murray 1978 (Approved Lists 1980) and Anoxyphotobacteriae Gibbons and Murray 1978 (Approved Lists 1980) are also rejected. The validly published phylum names have a variety of advantages over their not validly published counterparts and cannot be replaced with ad hoc names suggested in the literature. To ease the transition, it is recommended to mention the not validly published phylum names which strongly deviate in spelling from their validly published counterparts along with the latter in publications during the next years.
Closing the genome of unculturable cable bacteria using a combined metagenomic assembly of long and short sequencing reads
Authors: Hiralal Anwar , Geelhoed Jeanine S. , Hidalgo-Martinez Silvia , Smets Bent , van Dijk Jesper R. , Meysman Filip J. R.
Published: February 2024

Many environmentally relevant micro-organisms cannot be cultured, and even with the latest metagenomic approaches, achieving complete genomes for specific target organisms of interest remains a challenge. Cable bacteria provide a prominent example of a microbial ecosystem engineer that is currently unculturable. They occur in low abundance in natural sediments, but due to their capability for long-distance electron transport, they exert a disproportionately large impact on the biogeochemistry of their environment. Current available genomes of marine cable bacteria are highly fragmented and incomplete, hampering the elucidation of their unique electrogenic physiology. Here, we present a metagenomic pipeline that combines Nanopore long-read and Illumina short-read shotgun sequencing. Starting from a clonal enrichment of a cable bacterium, we recovered a circular metagenome-assembled genome (5.09 Mbp in size), which represents a novel cable bacterium species with the proposed name Candidatus Electrothrix scaldis. The closed genome contains 1109 novel identified genes, including key metabolic enzymes not previously described in incomplete genomes of cable bacteria. We examined in detail the factors leading to genome closure. Foremost, native, non-amplified long reads are crucial to resolve the many repetitive regions within the genome of cable bacteria, and by analysing the whole metagenomic assembly, we found that low strain diversity is key for achieving genome closure. The insights and approaches presented here could help achieve genome closure for other keystone micro-organisms present in complex environmental samples at low abundance.
Shigella sonnei utilises colicins during inter-bacterial competition
Authors: Leung P. B. , Matanza X. M. , Roche B. , Ha K. P. , Cheung H. C. , Appleyard S. , Collins T. , Flanagan O. , Marteyn B. S. , Clements A.
Published: February 2024

The mammalian colon is one of the most densely populated habitats currently recognised, with 1011–1013 commensal bacteria per gram of colonic contents. Enteric pathogens must compete with the resident intestinal microbiota to cause infection. Among these enteric pathogens are Shigella species which cause approximately 125 million infections annually, of which over 90 % are caused by Shigella flexneri and Shigella sonnei. Shigella sonnei was previously reported to use a Type VI Secretion System (T6SS) to outcompete E. coli and S. flexneri in in vitro and in vivo experiments. S. sonnei strains have also been reported to harbour colicinogenic plasmids, which are an alternative anti-bacterial mechanism that could provide a competitive advantage against the intestinal microbiota. We sought to determine the contribution of both T6SS and colicins to the anti-bacterial killing activity of S. sonnei. We reveal that whilst the T6SS operon is present in S. sonnei, there is evidence of functional degradation of the system through SNPs, indels and IS within key components of the system. We created strains with synthetically inducible T6SS operons but were still unable to demonstrate anti-bacterial activity of the T6SS. We demonstrate that the anti-bacterial activity observed in our in vitro assays was due to colicin activity. We show that S. sonnei no longer displayed anti-bacterial activity against bacteria that were resistant to colicins, and removal of the colicin plasmid from S. sonnei abrogated anti-bacterial activity of S. sonnei. We propose that the anti-bacterial activity demonstrated by colicins may be sufficient for niche competition by S. sonnei within the gastrointestinal environment.
Extracellular vesicles alter trophoblast function in pregnancies complicated by COVID-19
Authors: Golden Thea N. , Mani Sneha , Linn Rebecca L. , Leite Rita , Trigg Natalie A. , Wilson Annette , Anton Lauren , Mainigi Monica , Conine Colin C. , Kaufman Brett A. , Strauss Jerome F. , Parry Samuel , Simmons Rebecca A.
Published: February 2024

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and resulting coronavirus disease (COVID-19) causes placental dysfunction, which increases the risk of adverse pregnancy outcomes. While abnormal placental pathology resulting from COVID-19 is common, direct infection of the placenta is rare. This suggests that pathophysiology associated with maternal COVID-19, rather than direct placental infection, is responsible for placental dysfunction and alteration of the placental transcriptome. We hypothesized that maternal circulating extracellular vesicles (EVs), altered by COVID-19 during pregnancy, contribute to placental dysfunction. To examine this hypothesis, we characterized maternal circulating EVs from pregnancies complicated by COVID-19 and tested their effects on trophoblast cell physiologyin vitro. We found that the gestational timing of COVID-19 is a major determinant of circulating EV function and cargo.In vitrotrophoblast exposure to EVs isolated from patients with an active infection at the time of delivery, but not EVs isolated from Controls, altered key trophoblast functions including hormone production and invasion. Thus, circulating EVs from participants with an active infection, both symptomatic and asymptomatic cases, can disrupt vital trophoblast functions. EV cargo differed between participants with COVID-19 and Controls, which may contribute to the disruption of the placental transcriptome and morphology. Our findings show that COVID-19 can have effects throughout pregnancy on circulating EVs and circulating EVs are likely to participate in placental dysfunction induced by COVID-19.
Mechanical convergence in mixed populations of mammalian epithelial cell
Authors: Gauquelin Estelle , Kuromiya Keisuke , Namba Toshinori , Ikawa Keisuke , Fujita Yasuyuki , Ishihara Shuji , Sugimura Kaoru
Published: February 2024

Tissues consist of cells with different molecular and/or mechanical properties. Measuring the forces and stresses in mixed-cell populations is essential for understanding the mechanisms by which tissue development, homeostasis, and disease emerge from the cooperation of distinct cell types. However, many previous studies have primarily focused their mechanical measurements on dissociated cells or aggregates of a single-cell type, leaving the mechanics of mixed-cell populations largely unexplored. In the present study, we aimed to elucidate the influence of interactions between different cell types on cell mechanics by conducting in situ mechanical measurements on a monolayer of mammalian epithelial cells. Our findings revealed that while individual cell types displayed varying magnitudes of traction and intercellular stress before mixing, these mechanical values shifted in the mixed monolayer, becoming nearly indistinguishable between the cell types. Moreover, by analyzing a mixed-phase model of active tissues, we identified physical conditions under which such mechanical convergence is induced. Overall, the present study underscores the importance of in situ mechanical measurements in mixed-cell populations to deepen our understanding of the mechanics of multi-cellular systems.
Polyamine-mediated sensitization ofKlebsiella pneumoniaeto macrolides through a dual mode of action
Authors: Adams Joshua M. E. , Moulding Peri B. , El-Halfawy Omar M.
Published: February 2024

Chemicals bacteria encounter at the infection site could shape their stress and antibiotic responses; such effects are typically undetected in standard lab conditions. Polyamines are small molecules typically overproduced by the host during infection and have been shown to alter bacterial stress responses. We sought to determine the effect of polyamines on the antibiotic response ofKlebsiella pneumoniae, a Gram-negative priority pathogen. Interestingly, putrescine and other natural polyamines sensitizedK. pneumoniaeto azithromycin, a macrolide protein translation inhibitor typically used for Gram-positive bacteria. This synergy was further potentiated in the physiological buffer, bicarbonate. Chemical genomic screens suggested a dual mechanism whereby putrescine acts at the membrane and ribosome levels. Putrescine permeabilized the outer membrane ofK. pneumoniae(NPN and β-lactamase assays) and the inner membrane (Escherichia coliβ-galactosidase assays). Chemically and genetically perturbing membranes led to a loss of putrescine-azithromycin synergy. Putrescine also inhibited protein synthesis in anE. coli-derived cell-free protein expression assay simultaneously monitoring transcription and translation. Profiling the putrescine-azithromycin synergy against a combinatorial array of antibiotics targeting various ribosomal sites suggested that putrescine acts as tetracyclines targeting the 30S ribosomal acceptor site. Next, exploiting the natural polyamine-azithromycin synergy, we screened a polyamine analog library for azithromycin adjuvants, discovering four azithromycin synergists with activity starting from the low micromolar range and mechanisms similar to putrescine. This work sheds light on the bacterial antibiotic responses under conditions more reflective of those at the infection site and provides a new strategy to extend the macrolide spectrum to drug-resistantK. pneumoniae.
Designing monomeric IFNγ: the significance of domain-swapped dimer structure in IFNγ immune responses
Authors: Goto Yota , Miyafusa Takamitsu , Honda Shinya
Published: February 2024

IFNγ can initiate immune responses by inducing the expression of major histocompatibility complex molecules, suggesting its potential for cancer immunotherapy. However, it also has an immunosuppressive function that limits its application as a therapeutic agent. IFNγ has a characteristic domain-swapped dimer structure with two of the six α-helices exchanged with each other. As we hypothesized that the contrasting functions of IFNγ could be attributed to its unique domain-swapped structure, we designed monomeric IFNγ by transforming the domain-swapped dimer structure of wild-type IFNγ. We conjectured the evolution of this domain-swapped dimer and hypothesized that the current IFNγ structure emerged through shortening of the loop structure at the base of the swapped domain and the accumulation of hydrophobic amino acids at the newly generated interface during domain-swapping. We then designed and generated a stable monomeric IFNγ by retracing this evolutionary process, complementing the lost loop structure with a linker and replacing the accumulated hydrophobic amino acids with hydrophilic ones. We determined that the designed variant was a monomer based on molecular size and number of epitopes and exhibited activity in cell-based assays. Notably, the monomeric IFNγ showed a qualitatively similar balance between immunostimulatory and immunosuppressive gene expression as wild-type IFNγ. This study demonstrates that the structural format of IFNγ affects the strength of its activity rather than regulating the fate of downstream gene expression.
Tissue resident cells differentiate S. aureus from S. epidermidis via IL-1beta following barrier disruption in healthy human skin disruption in healthy human skin
Authors: Lang Julia C. , Brutscher Andreas , Ehrstrom Marcus , Melican Keira
Published: February 2024

The Staphylococcus species are a dominant part of the human skin microbiome and present across all body sites. Staphylococcus epidermidis is a ubiquitous skin commensal, while S. aureus is thought to colonize at least 30% of the population. S. aureus are not only colonizers but a leading cause of skin and soft tissue infections and a critical healthcare concern. To understand how healthy human skin may differentiate commensal bacteria, such as S. epidermidis, from the potential pathogen methicillin-resistant S. aureus (MRSA), we use ex vivo human skin models that allows us to study this host-bacterial interaction in the most clinically relevant environment. Our work highlights the role of the outer stratum corneum as a protective physical barrier against invasion by colonizing Staphylococci. We show how the structural cells of the skin can internalize and respond to different Staphylococci with increasing sensitivity. Disruption of the protective stratum corneum triggered an increased and discriminative immune response led by strong IL-1beta expression. We identified and localized tissue resident Langerhans cells (LCs) as a potential source of this IL-1beta and go on to show a dose dependent response of MUTZ-LCs to S. aureus but not S. epidermidis. This suggests an important role of LCs in sensing and discriminating between bacteria in healthy human skin. This work provides a detailed snapshot of how human skin differentiates between friend and potential foe. With the rise in antibiotic resistance, understanding the innate immune response of healthy skin may help us find ways to enhance or manipulate these natural defenses to help prevent invasive infection.
A UL26-PIAS1 complex antagonizes anti-viral gene expression during Human Cytomegalovirus infection
Authors: Ciesla Jessica Helen , Huang Kai-Lieh , Wagner Eric J. , Munger Joshua
Published: February 2024

Viral disruption of innate immune signaling is a critical determinant of productive infection. The Human Cytomegalovirus (HCMV) UL26 protein prevents anti-viral gene expression during infection, yet the mechanisms involved are unclear. We used TurboID-driven proximity proteomics to identify putative UL26 interacting proteins during infection to address this issue. We find that UL26 forms a complex with several immuno-regulatory proteins, including several STAT family members and various PIAS proteins, a family of E3 SUMO ligases. Our results indicate that UL26 prevents STAT phosphorylation during infection and antagonizes transcriptional activation induced by either interferon alpha (IFNA) or tumor necrosis factor alpha (TNFalpha). Additionally, we find that the inactivation of PIAS1 sensitizes cells to inflammatory stimulation, resulting in an anti-viral transcriptional environment that mirrors DeltaUL26 infection. Further, PIAS1 is important for HCMV cell-to-cell spread, which depends on the presence of UL26, suggesting that the UL26-PIAS1 interaction is vital for modulating intrinsic anti-viral defense.
Genetic potential for aerobic respiration and denitrification in globally distributed respiratory endosymbionts
Authors: Speth Daan R , Zeller Linus M , Graf Jon S , Overholt Will A , Kuesel Kirsten , Milucka Jana
Published: February 2024

The endosymbiont Candidatus Azoamicus ciliaticola generates ATP for its eukaryotic host, an anaerobic ciliate of the Plagiopylea class, fulfilling a function analogous to mitochondria in other eukaryotic cells. The discovery of this respiratory endosymbiosis has major implications for both evolutionary history and ecology of microbial eukaryotes. However, with only a single species described, knowledge of its environmental distribution and diversity is limited. Here we report four new complete, circular metagenome assembled genomes (cMAGs) representing respiratory endosymbionts inhabiting groundwater in California, Ohio, and Germany. These cMAGs form two lineages comprising a monophyletic clade within the uncharacterized gammaproteobacterial order UBA6186, enabling evolutionary analysis of their key protein complexes. Strikingly, all four novel cMAGs encode a cytochrome cbb3 oxidase, which indicates the capacity for both aerobic and anaerobic respiration. Accordingly, we detect these respiratory endosymbionts in diverse habitats worldwide, thus significantly expanding the ecological scope of this respiratory symbiosis.
Structural and biochemical characterization of an encapsulin-associated rhodanese fromAcinetobacter baumannii
Authors: Benisch Robert , Giessen Tobias W.
Published: February 2024

Rhodanese-like domains (RLDs) represent a widespread protein family canonically involved in sulfur transfer reactions between diverse donor and acceptor molecules. RLDs mediate these transsulfuration reactions via a transient persulfide intermediate, created by modifying a conserved cysteine residue in their active sites. RLDs are involved in various aspects of sulfur metabolism, including sulfide oxidation in mitochondria, iron-sulfur cluster biogenesis, and thio-cofactor biosynthesis. However, due to the inherent complexity of sulfur metabolism caused by the intrinsically high nucleophilicity and redox sensitivity of thiol-containing compounds, the physiological functions of many RLDs remain to be explored. Here, we focus on a single domainAcinetobacter baumanniiRLD (Ab-RLD) associated with a desulfurase encapsulin which is able to store substantial amounts of sulfur inside its protein shell. We determine the 1.6 Å x-ray crystal structure of Ab-RLD, highlighting a homodimeric structure with a number of unusual features. We show through kinetic analysis that Ab-RLD exhibits thiosulfate sulfurtransferase activity with both cyanide and glutathione acceptors. Using native mass spectrometry andin vitroassays, we provide evidence that Ab-RLD can stably carry a persulfide and thiosulfate modification and may employ a ternary catalytic mechanism. Our results will inform future studies aimed at investigating the functional link between Ab-RLD and the desulfurase encapsulin.
Efficacy of Topical Strategies to Prevent the Onset of Root Caries Lesions, In vitro.
Authors: Valenzuela-Ramos Ricardo , Leon Soraya , Giacaman Rodrigo A
Published: February 2024

Preventive fluoride-based topical products, such as silver diamine fluoride (SDF) and others with chlorhexidine have been widely used as a strategy for preventing dental caries lesions, at all ages. Whether they are effective against root caries is less clear. Aim: To evaluate the efficacy of various dental products in preventing root caries lesions, using a biological model of root caries. Methodology: An experimental in vitro study was devised using a validated model with biofilms of Streptococcus mutans formed on bovine root dentin slabs. Slabs were divided into 5 experimental groups: (1) 1% chlorhexidine gel, (2) 22,600 ppm fluoride varnish, (3) 5000 ppm fluoride toothpaste, (4) 38% SDF and (5) negative control (0.9% NaCl). After the experimental phases, biofilms were detached from the dentin slabs to assess biomass and the number of viable cells (CFU). Demineralization of dentin slabs was evaluated by laser fluorescence and surface Knoop microhardness loss. Results: Dentin slabs treated with SDF did not significantly differ in surface microhardness loss compared to those treated with 1% chlorhexidine gel (p>0.05). However, both materials showed significantly lower surface demineralization than the rest of the groups. SDF had a higher impact on the properties of Streptococcus mutans biofilms. Conclusion: SDF seems more effective than other materials in preventing root caries lesions in a highly cariogenic environment.
Complementarity in which-path resonant Auger scattering
Authors: Liu Ji-Cai , Gel'mukhanov Faris , Polyutov Sergey , Krasnov Pavel , Kimberg Victor
Published: February 2024

Different types of Young's double-slit experiments contain a significant amount of both particle and wave information running from full-particle to full-wave knowledge depending on the experimental conditions. We study the Young's double-slit interference in resonant Auger scattering from homonuclear diatomic molecules where opposite Doppler shifts for the dissociating atomic slits provide path information. Different quantitative formulation of Bohr's complementarity principle—path information vs interference—is applied to two types of resonant Auger scattering experiments, with fixed-in-space and randomly oriented molecules. Special attention is paid to the orientational dephasing in conventional Auger experiments with randomly oriented molecules. Our quantitative formulation of the complementarity is compared with the formulation made earlier by Greenberger and Yasin [D. M. Greenberger and A. Yasin, ].

Published by the American Physical Society
2024
Nonlinear optovibronics in molecular systems
Authors: Zhang Q. , Asjad M. , Reitz M. , Sommer C. , Gurlek B. , Genes C.
Published: February 2024

We analytically tackle optovibronic interactions in molecular systems driven by either classical or quantum light fields. In particular, we examine a simple model of molecules with two relevant electronic levels, characterized by potential landscapes with different positions of minima along the internuclear coordinates and of varying curvatures. Such systems exhibit an electron-vibron interaction, which can be composed of linear and quadratic terms in the vibrational displacement. By employing a combination of conditional displacement and squeezing operators, we present analytical expressions based on a quantum Langevin equations approach, to describe the emission and absorption spectra of such nonlinear molecular systems. Furthermore, we examine the imprint of the quadratic interactions onto the transmission properties of a cavity-molecule system within the collective strong-coupling regime of cavity quantum electrodynamics.

Published by the American Physical Society
2024
Sampling-free computation of finite temperature material properties in isochoric and isobaric ensembles using the mean-field anharmonic bond model
Authors: Dsouza Raynol , Poul Marvin , Huber Liam , Swinburne Thomas D. , Neugebauer Jörg
Published: February 2024

The recently introduced mean-field anharmonic bond model has shown remarkable accuracy in predicting finite temperature free energies for certain potential models of fcc crystals without thermodynamic sampling. In this work, we extend the model to treat modern machine learning potentials in both isochoric and isobaric ensembles while preserving existing vibrational correlations and ensuring thermodynamic self-consistency. Testing against molecular dynamics simulations of bulk fcc Al and Cu, we find free energies with an accuracy of a few meV/atom up to the melting temperature under typical operating pressures, with similar accuracy for thermal expansion. Our sampling-free estimation is universally superior to the quasiharmonic approximation for less than ten percent of the computational cost and many orders of magnitude more efficient than thermodynamic integration. We discuss applications of the method in modern computational materials science workflows.

Published by the American Physical Society
2024
Emergent Chern-Simons interactions in 3+1 dimensions
Authors: Stålhammar M. , Rudneva D. , Hansson T. H. , Wilczek F.
Published: February 2024

Parity-violating superconductors can support a low-dimension local interaction that becomes, upon condensation, a purely spatial Chern-Simons term. Solutions to the resulting generalized London equations can be obtained from solutions of the ordinary London equations with a complex penetration depth, and suggest several remarkable physical phenomena. The problem of flux exclusion by a sphere brings in an anapole moment, the problem of current-carrying wires brings in an azimuthal magnetic field, and the problem of vortices brings in currents along the vortices. We demonstrate that interactions of this kind, together with a conceptually related dimensionally reduced Chern-Simons interaction, can arise from physically plausible microscopic interactions.

Published by the American Physical Society
2024
New approach to the 3-momentum regularization of the in-medium one- and two-fermion line integrals with applications to cross sections in the Nambu–Jona-Lasinio model
Authors: Pereira Renan Câmara , Costa Pedro , Providência Constança , Moreira João
Published: February 2024

We propose the 3-momentum sphere intersection regularization applied to the one- and two-fermion line integrals at finite temperature and chemical potential. The quark-antiquark polarization function in this new regularization approach is equivalent to the usual 3-momentum regularization, when the absolute value of the external 3-momentum of the polarization is zero. Additionally, it respects the particle-antiparticle symmetry of meson states in the Nambu–Jona-Lasinio (NJL) model for all values of temperature and chemical potential. Without this symmetry, in-medium cross sections calculated in the 3-momentum regularized NJL model are not consistent. To demonstrate the difference between the usual 3-momentum regularization with the one proposed in this work, we study the quark-quark and quark-antiquark cross sections in both regularization schemes. To this end we use the standard SU(3) NJL model, with four- and six-quark interactions. We observe major quantitative and qualitative differences when comparing quark-quark cross sections in both schemes. The quark-antiquark cross sections, on the other hand, are very similar in both regularizations, owning to the equivalence between the regularizations when the absolute value of the external 3-momentum is zero.

Published by the American Physical Society
2024
Toward distinguishing Dirac from Majorana neutrino mass with gravitational waves
Authors: King Stephen F. , Marfatia Danny , Rahat Moinul Hossain
Published: February 2024

We propose a new method toward distinguishing the Dirac versus Majorana nature of neutrino masses from the spectrum of gravitational waves (GWs) associated with neutrino mass genesis. Motivated by the principle of generating small neutrino masses without tiny Yukawa couplings, we assume generic seesaw mechanisms for both Majorana and Dirac neutrino masses. For Majorana neutrinos, we further assume a spontaneously broken gauged U(1)B−L symmetry, independently of the type of Majorana seesaw mechanism, which gives a cosmic string induced GW signal flat over a wide range of frequencies. For Dirac neutrinos, we assume the spontaneous breaking of a Z2 symmetry, the minimal symmetry choice associated with all Dirac seesaw mechanisms, which is softly broken, generating a peaked GW spectrum from the annihilation of the resulting domain walls. In fact, the GW spectra for all types of Dirac seesaws with such a broken Z2 symmetry are identical, subject to a mild caveat. As an illustrative example, we study the simplest respective type-I seesaw mechanisms, and show that the striking difference in the shapes of the GW spectra can help differentiate between these Dirac and Majorana seesaws, complementing results of neutrinoless double beta decay experiments. We also discuss detailed implications of the recent NANOGrav data for Majorana and Dirac seesaw models.

Published by the American Physical Society
2024
Orientation memory of magnetic dipoles
Authors: Oblak Blagoje , Seraj Ali
Published: February 2024

We study the precession caused by electromagnetic radiation on a magnetic dipole located far from the source. As we show, this entails a net rotation of the dipole in the plane orthogonal to the direction of wave propagation, providing an electromagnetic analogue of gyroscopic gravitational memory. Like its gravitational cousin, the precession rate falls off with the square of the distance to the source, and is related to electric-magnetic duality and optical helicity on the celestial sphere. We use a multipolar expansion to compute the memory effect due to localized sources such as moving point charges, and highlight its occurrence in setups that break parity symmetry.

Published by the American Physical Society
2024
Parisi’s hypercube, Fock-space fluxes, and the microscopics of
near−AdS2/near−CFT1
duality
Authors: Berkooz Micha , Jia Yiyang , Silberstein Navot
Published: February 2024

Parisi’s hypercube model describes a charged particle hopping on a d-dimensional hypercube with disordered background fluxes in the large d limit. It was noted previously [Jia and Verbaarschot, ] that the hypercube model at leading order in 1/d has the same spectral density as the double-scaled Sachdev-Ye-Kitaev (DS-SYK) model. In this work we identify the set of observables that have the same correlation functions as the DS-SYK model, demonstrating that the hypercube model is an equally good microscopic model for near−AdS2/near−CFT1 holography. Unlike the SYK model, the hypercube model is not p-local. Rather, we note that the shared feature between the two models is that they both have a large amount of disordered but uniform fluxes on their Fock-space graphs, and we propose this is a broader characterization of near−CFT1 microscopics. Moreover, we suggest that the hypercube model can be viewed as the operator growth model of the DS-SYK model. We explain some universality in subleading corrections and relate them to bulk vertices. Finally, we revise a claim made in the aforementioned reference about the existence of a spectral gap.

Published by the American Physical Society
2024
Dual-species Bose-Einstein condensates of
Na23
and
K41
with tunable interactions
Authors: Chang Jaeryeong , Lee Sungjun , Kim Yoonsoo , Lim Younghoon , Park Jee Woo
Published: February 2024

We report the creation of dual-species Bose-Einstein condensates (BECs) of Na23 and K41. Favorable background scattering lengths enable efficient sympathetic cooling of K41 via forced evaporative cooling of Na23 in a plugged magnetic trap and an optical dipole trap. The 1/e lifetime of the thermal mixture in the stretched hyperfine state exceeds 5 s in the presence of background scattering. At the end of evaporation, we create dual BECs in the immiscible phase, with about 3×105 Na23 atoms surrounding 5×104 K41 atoms. To further enable the tuning of the interspecies interaction strength, we locate multiple Feshbach resonances at magnetic fields up to 100 G. The broadest s-wave resonance located at 73.4(3) G features a favorable width of 1.8(2) G. This work sets the stage for the creation of ultracold gases of strongly dipolar bosonic Na23K41 molecules as well as the exploration of many-body physics in bosonic Na23−K41 mixtures.

Published by the American Physical Society
2024
Influence of magnetism on vertical hopping transport in CrSBr
Authors: Lin Xiaohanwen , Wu Fan , López-Paz Sara A. , von Rohr Fabian O. , Gibertini Marco , Gutiérrez-Lezama Ignacio , Morpurgo Alberto F.
Published: February 2024

We investigate the c-direction conduction in CrSBr in the linear regime, which is not accessible in other van der Waals (vdW) magnetic semiconductors, because of the unmeasurably low current. The resistivity, which is 108−1011 times larger than in the a and b directions, exhibits magnetic state dependent thermally activated and variable range hopping transport. In the spin-flip phase at 2 T, the activation energy is 20 meV lower than in the antiferromagnetic state due to a downshift of the conduction band edge, in agreement with calculations. In the variable range hopping regime, the average hopping length decreases from twice the interlayer distance to the interlayer distance at 2 T because in the antiferromagnetic state the large exchange energy impedes electrons hopping between adjacent layers. Our work demonstrates that the linear transport regime provides new information about electronic processes in vdW magnetic semiconductors and shows how magnetism influences these processes both in real and reciprocal space.

Published by the American Physical Society
2024
Synthesis and crystal structures of bis[1-oxopyridin-2-olato(1−)]bis(pentafluorophenyl)silicon(IV)–tetrahydrofuran–pentane (2/1/1), bis[1-oxopyridin-2-olato(1−)]bis(p-tolyl)silicon(IV), and dimesitylbis[1-oxopyridin-2-olato(1−)]silicon(IV)
Authors: Kraft Bradley M. , Brennessel William W. , Andrews Jordan W. , Viggiani Michael T. , Kittrell Nathan F. , Heckman Matthew T.
Published: February 2024

The neutral organosilicon(IV) complex, (C6F5)2Si(OPO)2 (OPO = 1-oxopyridin-2-one, C5H4NO2), was synthesized from (C6F5)2Si(OCH3)2 and 2 equiv. of 1-hydroxypyridin-2-one in tetrahydrofuran (THF). Single crystals grown from the diffusion of n-pentane into a THF solution were identified as a THF hemisolvate and an n-pentane hemisolvate, (C6F5)2Si(OPO)2·0.5THF·0.5C5H12 (1). p-Tolyl2Si(OPO)2 (2) and mesityl2Si(OPO)2 (3) crystallized directly from reaction mixtures of 2 equiv. of Me3Si(OPO) with p-tolyl2SiCl2 and mesityl2SiCl2, respectively, in acetonitrile. The oxygen-bonded carbon and nitrogen atoms of the OPO ligands in 1, 2, and 3 were modeled as disordered indicating co-crystallization of up to three possible diastereomers in each. Solution NMR studies support the presence of exclusively the all-cis isomer in 1 and multiple isomers in 2. Poor solubility of 3 limited its characterization in solution.
Empowering families traveling with young children: a transformative service research perspective
Authors: An Jiyoon
Published: February 2024

Purpose

This study aims to explore families that travel with children, as focuses on vulnerabilities, resource constraints and service exclusion through the lens of transformative service research (TSR). This paper investigates: how the experienced vulnerability of these families is shaped by structural, interpersonal and intrapersonal constraints, and how the constraints influence the family tourist-resource interaction in the air travel service encounter.

Design/methodology/approach

In total, 2,855 reviews of the family tourists with children were analyzed with text mining, t-test and multidimensional scaling using the interpretive language R to answer the research questions with analyses on unstructured (e.g. text) and structured (e.g. consumer rating) data.

Findings

The findings of the empirical investigation answered how experienced vulnerability is shaped by structural, interpersonal and intrapersonal resource constraints and the types of family tourist-resource interaction in the travel service encounter to understand the resource constraints. The findings of this paper help examine family tourism experiences from a value formation perspective to unfold how stakeholders interact to form value while increasing and decreasing their well-being by the value of co-creation and co-destruction.

Originality/value

This research helps advance the TSR’s service inclusion framework by enabling opportunities, offering choice, relieving suffering and fostering happiness with empirical findings in travel service encounters. These findings are particularly insightful to family tourists with children struggling with unfair access and treatment in aeromobility service encounters, which may help enhance the well-being of individuals and communities.
Sharing the ownership in Peru and Mexico: the case of a French MNE prompting the SDGs achievement
Authors: Aubert Nicolas , Cordova Miguel , Hernandez Gonzalo
Published: February 2024

Purpose

This study aims to investigate how a French multinational enterprise (MNE) is developing employee stock ownership (ESO) in its subsidiaries in Peru and Mexico, both Latin American countries with deep social and economic inequalities.

Design/methodology/approach

This is a qualitative case study which conducted interviews with representatives of the French MNE and its subsidiaries in Peru and Mexico.

Findings

The employee stock purchase plans offered by the company to its employees support the achievement of the sustainable development goals (SDGs) 1, 8 and 10 in these countries.

Social implications

The authors argue that MNEs could become flagships in the SDG achievement in emerging economies.

Originality/value

By contributing to better workplace outcomes and enhanced corporate performance, ESO is in line with SDG 8. ESO also fulfills SDGs 1 and 10 by allowing employees to build up savings and wealth, whose lack is the main source of inequality and poverty. Reciprocity and binary economics theories explain these relationships.
Evaluation of risk factors affecting the safety of coal mine construction projects using an integrated DEMATEL-ISM approach
Authors: Shi Xiaobo , Liu Yan , Ma Kunkun , Gu Zixin , Qiao Yaning , Ni Guodong , Ojum Chibuzor , Opoku Alex , Liu Yong
Published: February 2024

Purpose

The purpose is to identify and evaluate the safety risk factors in the coal mine construction process.

Design/methodology/approach

The text mining technique was applied in the stage of safety risk factor identification. The association rules method was used to obtain associations with safety risk factors. Decision-Making Trial and Evaluation Laboratory (DEMATEL) and Interpretative Structural Modeling (ISM) were utilized to evaluate safety risk factors.

Findings

The results show that 18 safety risk factors are divided into 6 levels. There are 12 risk transmission paths in total. Meanwhile, unsafe behavior and equipment malfunction failure are the direct causes of accidents, and inadequate management system is the basic factor that determines the safety risk status.

Research limitations/implications

Due to the limitation of the computational matrix workload, this article only categorizes numerous lexical items into 18 factors. Then, the workshop relied on a limited number of experts; thus, the findings may be potentially biased. Next, the accident report lacks a universal standard for compilation, and the use of text mining technique may be further optimized. Finally, since the data are all from China, subsequent cross-country studies should be considered.

Social implications

The results can help China coal mine project managers to have a clear understanding of safety risks, efficiently carry out risk hazard identification work and take timely measures to cut off the path of transmission with risks identified in this study. This helps reduce the economic losses of coal mining enterprises, thus improving the safety standards of the entire coal mining industry and the national standards for coal mine safety policy formulation.

Originality/value

Coal mine construction projects are characterized by complexity and difficulties in construction. Current research on the identification and assessment of safety risk factors in coal mine construction is insufficient. This study combines objective and systematic research approaches. The findings contribute to the safety risk management of China coal mine construction projects by providing a basis for the development of safety measures.
Application of simulation and virtual reality to production learning
Authors: Ruiz de la Torre Acha Aitor , Rio Belver Rosa María , Fernandez Aguirrebeña Javier , Merlo Christophe
Published: February 2024

Purpose

This study explores the impact of new technologies, such as simulation and virtual reality, on the pedagogy and learning of engineering students. It aims to compare the effectiveness of these digital tools against traditional teaching methods in enhancing student learning experiences.

Design/methodology/approach

Utilizing a quantitative research approach, the study involved third-year engineering students from the “Production Management” course at the School of Engineering of Vitoria-Gasteiz. Data were collected through an ad hoc questionnaire and analyzed using SPSS software, focusing on student satisfaction, challenges in adopting new technologies and the evolving roles of students and teachers.

Findings

The research highlighted several key aspects. Firstly, it identified the need for adapting teaching methods to incorporate new technologies effectively. Secondly, the integration of simulation and virtual reality was found to facilitate a deeper understanding of real-world problems, as students could engage with these issues in a simulated, virtual environment. Finally, the study emphasized the importance of pedagogical approaches that leverage these technologies to increase student involvement and motivation. The results suggest a positive impact of digital tools on the learning process in engineering education.

Research limitations/implications

The study’s scope was limited to one course within a single institution, suggesting the need for broader research across various disciplines and educational settings.

Originality/value

This research offers valuable insights into the integration of simulation and virtual reality in engineering education, underscoring their potential to enhance the learning experience and knowledge acquisition among students.
Financial knowledge and responsible credit card behavior: exploring mediators and moderators
Authors: Chen Fuzhong , Jiang Guohai , Gu Mengyi
Published: February 2024

Purpose

Under the background of low consumer financial knowledge and accumulated credit card liabilities, this study investigates the relationship between financial knowledge and responsible credit card behavior using data from the 2019 China Household Finance Survey (CHFS). From the perspective of consumer economic well-being, this study defines accruing credit card debt to buy houses and cars when loans with lower interest rates are available as irresponsible credit card behavior.

Design/methodology/approach

This study uses probit regressions to examine the association between financial knowledge and responsible credit card behavior because the dependent variable is a dummy variable. To alleviate endogeneity problems, this study uses instrument variables and Heckman’s two-step estimation. Furthermore, to explore the potential mediators in this process, this study follows the stepwise regression method. Finally, this study introduces interaction terms to examine whether this association differs in different groups.

Findings

The results indicate that financial knowledge is conducive to increasing the probability of responsible credit card behavior. Mediating analyses reveal that the roles of financial knowledge occur by increasing the degree of concern for financial and economic information and the propensity to plan. Moderating analyses show that the effects of financial knowledge on responsible credit card behavior are stronger among risk-averse consumers and in regions with favorable digital access.

Originality/value

This study measures responsible credit card behavior from the perspective of the consumer’s well-being, which enriches practical implications for consumer finance. Furthermore, this study explores the potential mediators influencing the process of financial knowledge that affects responsible credit card behavior and identifies moderators to conduct heterogeneous analyses, which helps comprehensively understand the nexus between financial knowledge and credit card behavior. By achieving these contributions, this study helps to curb the adverse effects of irresponsible credit card behavior on consumers’ well-being and the economic system and helps policymakers promote financial knowledge to fully prevent irresponsible credit card behavior.