bluuebunny/crossref_metadata_2025 huggingface dataset:
Transcriptional repression and enhancer decommissioning silence cell cycle genes in postmitotic tissues
Authors: Fogarty Elizabeth A. , Buchert Elli M. , Ma Yiqin , Nicely Ava B. , Buttitta Laura A.
Published: May 2024

The mechanisms that maintain a non-cycling status in postmitotic tissues are not well understood. Many cell cycle genes have promoters and enhancers that remain accessible even when cells are terminally differentiated and in a non-cycling state, suggesting their repression must be maintained long term. In contrast, enhancer decommissioning has been observed for rate-limiting cell cycle genes in theDrosophilawing, a tissue where the cells die soon after eclosion, but it has been unclear if this also occurs in other contexts of terminal differentiation. In this study, we show that enhancer decommissioning also occurs at specific, rate-limiting cell cycle genes in the long-lived tissues of theDrosophilaeye and brain, and we propose this loss of chromatin accessibility may help maintain a robust postmitotic state. We examined the decommissioned enhancers at specific rate-limiting cell cycle genes and show that they encode dynamic temporal and spatial expression patterns that include shared, as well as tissue-specific elements, resulting in broad gene expression with developmentally controlled temporal regulation. We extend our analysis to cell cycle gene expression and chromatin accessibility in the mammalian retina using a published dataset, and find that the principles of cell cycle gene regulation identified in terminally differentiatingDrosophilatissues are conserved in the differentiating mammalian retina. We propose a robust, non-cycling status is maintained in long-lived postmitotic tissues through a combination of stable repression at most cell cycle gens, alongside enhancer decommissioning at specific rate-limiting cell cycle genes.

Highlights

In long-lived postmitoticDrosophilatissues, most cell cycle genes retain accessible chromatin despite persistent transcriptional downregulation.

Cell cycle genes with accessible enhancers remain activatable during terminal differentiation, suggesting their repression must be continuously maintained in the postmitotic state.

Long-lived postmitotic tissues decommission enhancers at specific, rate-limiting cell cycle genes in a developmentally regulated manner.

Genome-wide enhancer identification performed in cell culture misses many developmentally dynamic enhancersin vivo.

Decommissioned enhancers at cell cycle genes include shared and tissue-specific elements that in combination, result in broad gene expression with temporal regulation.

The principles of cell cycle gene regulation identified inDrosophilaare conserved in the mammalian retina.
Proteomic Profiling of Mesenchymal Stem Cell-Derived Extracellular Vesicles: Impact of Isolation Methods on Protein Cargo
Authors: Abyadeh Morteza , Mirshahvaladi Shahab , Assar Kashani Sara , A. Paulo Joao , Amirkhani Ardeshir , Mehryab Fatemeh , Seidi Homeira , Moradpour Niloufar , Jodeiryjabarzade Sheyda , Mirzaei Mehdi , Gupta Vivek , Shekari Faezeh , Hosseini Salekdeh Ghasem
Published: May 2024

Extracellular vesicles (EVs) are nanosized vesicles with a lipid bilayer that are secreted by cells and play a critical role in cell-to-cell communication. Despite the promising reports regarding their diagnostic and therapeutic potential, the utilization of EVs in the clinical setting is limited due to insufficient information about their cargo and a lack of standardization in isolation and analysis methods. Considering protein cargos in EVs as key contributors to their therapeutic potency, we conducted a tandem mass tag (TMT) quantitative proteomics analysis of three subpopulations of mesenchymal stem cell (MSC)-derived EVs obtained through three different isolation techniques: ultracentrifugation (UC), high-speed centrifugation (HS), and ultracentrifugation on sucrose cushion (SU). Subsequently, we checked EV marker expression, size distribution, and morphological characterization, followed by bioinformatic analysis. The bioinformatic analysis of the proteome results revealed that these subpopulations exhibit distinct molecular and functional characteristics. The choice of isolation method impacts the proteome of isolated EVs by isolating different subpopulations of EVs. Specifically, EVs isolated through the high-speed centrifugation (HS) method exhibited a higher abundance of ribosomal and mitochondrial proteins. Functional apoptosis assays comparing isolated mitochondria with different EV isolation methods revealed that HS-EVs, but not other EVs, induced early apoptosis in cancer cells. On the other hand, EVs isolated using the sucrose cushion (SU) and ultracentrifugation (UC) methods demonstrated a higher abundance of proteins primarily involved in the immune response, cellLJcell interactions, and extracellular matrix interactions. Our analyses unveil notable disparities in proteins and associated biological functions among EV subpopulations, underscoring the importance of meticulously selecting isolation methods and resultant EV subpopulations based on the intended application.
Helping behavior is associated with increased affiliative behavior, activation of the prosocial brain network and elevated oxytocin receptor expression in the nucleus accumbens
Authors: Hazani R. , Breton J.M. , Trachtenberg E. , Kantor B. , Maman A. , Bigelman E. , Cole S. , Weller A. , Ben-Ami Bartal I.
Published: May 2024

A prosocial response to others in distress is increasingly recognized as a natural behavior for many social species, from humans to rodents. While prosocial behavior is more frequently observed towards familiar conspecifics, even within the same social context some individuals are more prone to help than others. For instance, in a rat helping behavior test, rats can release a distressed conspecific trapped inside a restrainer by opening the restrainer door. Typically, rats are motivated to release a trapped cagemate, and consistently release the trapped rat (‘openers’), yet around 30% do not open the restrainer (‘non-openers’). To characterize the difference between these populations, behavioral and neural activity were compared between opener and non-opener rats tested with a trapped cagemate in the helping test. Behaviorally, openers showed significantly more social affiliative behavior both before and after door-opening compared to non-openers. Analysis of brain-wide neural activity based on the immediate early gene c-Fos revealed increased activity in openers in the previously identified prosocial neural network compared to non-openers. The network includes regions associated with empathy in humans (somatosensory cortex, insula, cingulate cortex and frontal cortex), and motivation and reward regions such as the nucleus accumbens. Oxytocin receptor mRNA expression levels were higher in the accumbens but not the anterior insula. Several transcription control pathways were also significantly upregulated in openers’ accumbens. These findings indicate that prosocial behavior may be predicted by affiliative behavior and activity in the prosocial neural network and provide targets for the investigation of causal mechanisms underlying prosocial behavior.

Significance Statement

Prosocial behavior is observed in many social species, including rodents, yet the determinants underlying why some animals help and others do not is poorly understood. Here, we show behavioral and neural differences between prosocial and non-prosocial pairs in a rat helping behavior test, with increased social interaction and nucleus accumbens oxytocin receptor gene expression in animals that helped.
A Comparative Study of Explainability Methods for Whole Slide Classification of Lymph Node Metastases using Vision Transformers
Authors: Rahnfeld Jens , Naouar Mehdi , Kalweit Gabriel , Boedecker Joschka , Dubruc Estelle , Kalweit Maria
Published: May 2024

Recent advancements in deep learning (DL), such as transformer networks, have shown promise in enhancing the performance of medical image analysis. In pathology, automated whole slide imaging (WSI) has transformed clinical workflows by streamlining routine tasks and diagnostic and prognostic support. However, the lack of transparency of DL models, often described as “black boxes”, poses a significant barrier to their clinical adoption. This necessitates the use of explainable AI methods (xAI) to clarify the decision-making processes of the models. Heatmaps can provide clinicians visual representations that highlight areas of interest or concern for the prediction of the specific model. Generating them from deep neural networks, especially from vision transformers, is non-trivial, as typically their self-attention mechanisms can lead to overconfident artifacts. The aim of this work is to evaluate current xAI methods for transformer models in order to assess which yields the best heatmaps in the histopathological context. Our study undertakes a comparative analysis for classifying a publicly available dataset comprising of N=400 WSIs of lymph node metastases of breast cancer patients. Our findings indicate that heatmaps calculated from Attention Rollout and Integrated Gradients are limited by artifacts and in quantitative performance. In contrast, removal-based methods like RISE and ViT-Shapley exhibit better qualitative attribution maps, showing better results in the well-known interpretability metrics for insertion and deletion. In addition, ViT-Shapley shows faster runtime and the most promising, reliable and practical heatmaps. Incorporating the heatmaps generated from approximate Shapley values in pathology reports could help to integrate xAI in the clinical workflow and increase trust in a scalable manner.
A low pre-existing anti-NS1 humoral immunity to DENV is associated with microcephaly development after gestational ZIKV exposure
Authors: Castro-Trujillo Sebastián , Mejía William R. , Segura Katherine , Vega Rocío , Salgado Doris , Fonseca Carlos E. , Ortiz Ángela M. , Perdomo-Celis Federico , Bosch Irene , Narváez Carlos F.
Published: May 2024

Background

Gestational Zika virus (ZIKV) infection is associated with the development of congenital Zika syndrome (CZS), which includes microcephaly and fetal demise. The magnitude and quality of orthoflavivirus-specific humoral immunity have been previously linked to the development of CZS. However, the role of ZIKV NS1-specific humoral immunity in mothers and children with prenatal ZIKV exposure and CZS remains undefined. In addition, considering that most of the at-risk population lives in dengue virus (DENV)-endemic areas, it is not clear what is the association between pre-existing DENV NS1-specific humoral immunity and CZS.

Methods

Here, we studied 328 mothers and children with a clinical diagnosis and seropositivity for ZIKV infection during pregnancy, included during the 2015-2016 ZIKV epidemic in Colombia. We also performed clinical evaluation and pediatric neurological follow-up. The relative levels of circulating NS1-specific IgM and IgG against ZIKV and DENV were evaluated in mothers and children, and the association with the development of microcephaly was analyzed.

Results

DENV and ZIKV IgG-NS1 antibodies in pregnant women were placentally transferred, and this passage and its duration in children depended on the maternal levels of the antibodies. We reported that higher concentrations of pre-existing DENV, but not ZIKV IgG-NS1 antibodies, were associated with a reduced risk of CZS-related microcephaly. Also, we observed that the IgM-NS1 response presents as long-term and has a minor association with poor outcomes.

Conclusions

The development of microcephaly in children prenatally exposed to ZIKV is associated with low plasma levels of placentally transferred, pre-existing DENV IgG-NS1 antibodies. These data are compatible with a protective role of anti-NS1 IgG antibodies against ZIKV infection during pregnancy and highlight the promising role of NS1 as an orthoflavivirus vaccine target in high-risk populations.
Evolution of the sex-determination geneDoublesexwithin the termite lineage
Authors: Fujiwara Kokuto , Miyazaki Satoshi , Maekawa Kiyoto
Published: May 2024

The molecular mechanism of sex determination has long been considered conserved in insects. However, recent studies of hemimetabolous insects have challenged this notion. One notable example is termites. InReticulitermes speratus, a homolog of sex determination gene,Doublesex(RsDsx), exhibits characteristics that are distinct from those of other insects, including sister-group cockroaches. It comprises a single exon, contains only doublesex/mab-3 DNA-binding domain (DM) but lacks a conserved oligomerization domain (OD), and exhibits transcriptional activity only in males. To investigate whether these characteristics are widespread within the termite lineage, we identifiedDsxhomologs in three different families. The loss of the conserved OD sequences was observed in all termite species examined, whereas the number of exons and expression patterns between sexes varied among families. Particularly, distinctive differences inDsxwere found in species from the Archotermopsidae and Kalotermitidae, both of which have a linear caste developmental pathway. Our findings indicate that diversification ofDsxstructure and expression patterns may have contributed to ecological diversification, such as caste developmental pathways, within the termite lineage.
Repeated fasting events sensitize enhancers, transcription factor activity and gene expression to support augmented ketogenesis
Authors: Korenfeld Noga , Charni-Natan Meital , Bruse Justine , Goldberg Dana , Marciano-Anaki Dorin , Rotaro Dan , Gorbonos Tali , Radushkevitz-Frishman Talia , Polizzi Arnaud , Nasereddin Abed , Bar-Shimon Meirav , Fougerat Anne , Guillou Hervé , Goldstein Ido
Published: May 2024

Mammals withstand frequent and prolonged fasting periods due to hepatic production of ketone bodies. Because the fasting response is transcriptionally-regulated, we asked whether enhancer dynamics impose a transcriptional program during recurrent fasting and whether this generates effects distinct from a single fasting bout. We found that mice undergoing alternate-day fasting (ADF) respond profoundly differently to a following fasting bout compared to mice first experiencing fasting. Hundreds of genes enabling ketogenesis are ‘sensitized’ (induced more strongly by fasting following ADF). Liver enhancers regulating these genes are also sensitized and harbor increased binding of PPARα, the main ketogenic transcription factor. ADF leads to augmented ketogenesis compared to a single fasting bout in wild-type, but not hepatocyte-specific PPARα-deficient mice. Thus, we found that past fasting events are ‘remembered’ in hepatocytes, sensitizing their enhancers to the next fasting bout and augment ketogenesis. Our findings shed light on transcriptional regulation mediating adaptation to repeated signals.
When does a parasite become a disease? eDNA unravels complex host-pathogen dynamics across environmental stress gradients in wild salmonid populations
Authors: Eloïse Duval , Simon Blanchet , Erwan Quéméré , Lisa Jacquin , Charlotte Veyssière , Géraldine Loot
Published: May 2024

Infectious diseases stem from disrupted interactions among hosts, parasites, and the environment. Both abiotic and biotic factors can influence infection outcomes by shaping the abundance of a parasite’s infective stages, as well as the host’s ability to fight infection. However, disentangling these mechanisms within natural ecosystems remains challenging. Here, combining environmental DNA analysis and niche modeling at a regional scale, we uncovered the biotic and abiotic drivers of a lethal infectious disease of salmonid fish, triggered by the parasiteTetracapsuloides bryosalmonae.We found that the occurrence and abundance of the parasite in the water—i.e., the propagule pressure— were mainly correlated to the abundances of its two primary hosts, the bryozoanFredericella sultanaand the fishSalmo trutta, but poorly to local abiotic environmental stressors. In contrast, the occurrence and abundance of parasites within fish hosts—i.e., proxies for disease emergence—were closely linked to environmental stressors (water temperature, agricultural activities, dams), and to a lesser extent to parasite propagule pressure. These results suggest that pathogen distribution alone cannot predict the risk of disease in wildlife, and that local anthropogenic stressors may play a pivotal role in disease emergence among wild host populations, likely by compromising the hosts’ ability to fight the parasite. Our study sheds light on the intricate interplay between biotic and abiotic factors in shaping pathogen distribution and raises concerns about the effects of global change on disease emergence.
Purinergic Signaling Drives Multiple Aspects of Rotavirus Pathophysiology
Authors: Engevik Kristen A. , Scribano Francesca J. , Gebert J. Thomas , Hyser Joseph M.
Published: May 2024

Rotavirus causes life-threatening diarrhea in children, resulting in ∼200,000 deaths/year. The current treatment during infection is Oral Rehydration Solution which successfully replenishes fluids but does not alleviate diarrhea volume or severity. As a result, there is an urgent need to better understand rotavirus pathophysiology and develop more effective pediatric therapeutics. Rotavirus primarily infects the tips of small intestinal villi, yet has far-reaching effects on cell types distant from infected cells. We recently identified that rotavirus infected cells release the purinergic signaling molecule ADP, which activates P2Y1 receptors on nearby uninfected cellsin vitro. To elucidate the role of purinergic signaling via P2Y1 receptors during rotavirus infectionin vivo, we used the mouse-like rotavirus strain D6/2 which generates a severe infection in mice. C57BL/6J mouse pups were given an oral gavage of D6/2 rotavirus and assessed over the course of 5-7 days. Beginning at day 1 post infection, infected pups were treated daily by oral gavage with saline or 4 mg/kg MRS2500, a selective P2Y1 antagonist. Mice were monitored for diarrhea severity, diarrhea incidence, and viral shedding. Neonatal mice were euthanized at days 3 and 5 post-infection and small intestine was collected to observe infection. MRS2500 treatment decreased the severity, prevalence, and incidence of rotavirus diarrhea. Viral stool shedding, assessed by qPCR for rotavirus gene levels, revealed that MRS2500 treated pups had significantly lower viral shedding starting at day 4 post infection compared to saline treated pups, which suggests P2Y1 signaling may enhance rotavirus replication. Finally, we found that inhibition of P2Y1 with MRS2500 limited transmitted rotavirus diarrhea to uninfected pups within a litter. Together, these results suggest that P2Y1 signaling is involved in the pathogenesis of a homologous murine rotavirus strain, making P2Y1 receptors a promising anti-diarrheal, anti-viral therapeutic target to reduce rotavirus disease burden.
Compartmentalized CRISPR Reactions (CCR) for High-Throughput Screening of Guide RNA Potency and Specificity
Authors: Supakar Tinku , Herring-Nicholas Ashley , Josephs Eric A.
Published: May 2024

CRISPR ribonucleoproteins (RNPs) use a variable segment in their guide RNA (gRNA) called a spacer to determine the DNA sequence at which the effector protein will exhibit nuclease activity and generate target-specific genetic mutations. However, nuclease activity with different gRNAs can vary considerably, in a spacer sequence-dependent manner that can be difficult to predict. While computational tools are helpful in predicting a CRISPR effector’s activity and/or potential for off-target mutagenesis with different gRNAs, individual gRNAs must still be validated in vitro prior to their use. Here, we present compartmentalized CRISPR reactions (CCR) for screening large numbers of spacer/target/off-target combinations simultaneously in vitro for both CRISPR effector activity and specificity, by confining the complete CRISPR reaction of gRNA transcription, RNP formation, and CRISPR target cleavage within individual water-in-oil microemulsions. With CCR, large numbers of the candidate gRNAs (output by computational design tools) can be immediately validated in parallel, and we show that CCR can be used to screen hundreds of thousands of extended gRNA (x-gRNAs) variants that can completely block cleavage at off-target sequences while maintaining high levels of on-target activity. We expect CCR can help to streamline the gRNA generation and validation processes for applications in biological and biomedical research.
Structures of native SV2A reveal the binding mode for tetanus neurotoxin and anti-epileptic racetams
Authors: Schenck Stephan , Laeremans Toon , Steyaert Jan , Brunner Janine D.
Published: May 2024

The synaptic vesicle glycoprotein 2A (SV2A) is abona fidesynaptic vesicle (SV) constituent of controversial function with homology to the major facilitator superfamily (MFS) and essential in vertebrate neurotransmission. Despite its high medical relevance as the target of the anti-epileptic drug Levetiracetam (LEV) and as receptor for clostridial neurotoxins (CNTs), among them several botulinum neurotoxin (BoNT) serotypes and potentially tetanus neurotoxin (TeNT), we lack detailed insight about these molecular interactions. We purified native SV2A from brain and subjected it to a structural analysis to advance our understanding of drug-binding to this enigmatic protein and explore structurally uncharacterized toxin-SV2A interfaces. Our analysis uncovered that TeNT binds SV2 proteins strikingly different from BoNT/A and delivers visual evidence for the dual receptor hypothesis through structurally resolved, co-purified gangliosides in the complex. The structures provide compelling support for SV2A as the protein receptor for TeNT in central neurons, recapitulate the geometry of CNT binding to dipartite SV2-ganglioside receptors on neuronal surfaces in a membrane-like constellation and have implications for toxin-engineering through a previously unknown SV2A-toxin interface. Further, a LEV-bound structure of SV2A reveals the drug-interacting residues and delineates a putative substrate pocket in SV2A. Our work provides an explanation for the SV2-isoform-specificity of LEV and its derivatives and paves the way for improved design of anti-convulsant drugs in epilepsy treatment.
AR coactivators, CBP/p300, are critical mediators of DNA repair in prostate cancer
Authors: Sardar Sumaira , McNair Christopher M. , Ravindranath Lakshmi , Chand Saswati N. , Yuan Wei , Bogdan Denisa , Welti Jon , Sharp Adam , Ryan Natalie K. , Schiewer Matthew J. , DeArment Elise G. , Janas Thomas , Su Xiaofeng A. , Butler Lisa M. , de Bono Johann S. , Frese Kris , Brooks Nigel , Pegg Neil , Knudsen Karen E. , Shafi Ayesha A.
Published: May 2024

Castration resistant prostate cancer (CRPC) remains an incurable disease stage with ineffective treatments options. Here, the androgen receptor (AR) coactivators CBP/p300, which are histone acetyltransferases, were identified as critical mediators of DNA damage repair (DDR) to potentially enhance therapeutic targeting of CRPC. Key findings demonstrate that CBP/p300 expression increases with disease progression and selects for poor prognosis in metastatic disease. CBP/p300 bromodomain inhibition enhances response to standard of care therapeutics. Functional studies, CBP/p300 cistrome mapping, and transcriptome in CRPC revealed that CBP/p300 regulates DDR. Further mechanistic investigation showed that CBP/p300 attenuation via therapeutic targeting and genomic knockdown decreases homologous recombination (HR) factorsin vitro,in vivo, and in human prostate cancer (PCa) tumorsex vivo. Similarly, CBP/p300 expression in human prostate tissue correlates with HR factors. Lastly, targeting CBP/p300 impacts HR-mediate repair and patient outcome. Collectively, these studies identify CBP/p300 as drivers of PCa tumorigenesis and lay the groundwork to optimize therapeutic strategies for advanced PCa via CBP/p300 inhibition, potentially in combination with AR-directed and DDR therapies.
A 3D whole-face movement analysis system to uncover underlying physiology in mice
Authors: Daruwalla Kyle , Martin Irene Nozal , Frankel Andrew , Naglič Diana , Ahmad Zainab , Hou Xun Helen
Published: May 2024

Synchronous movements of the entire face, from chewing to grimacing, offer significant insights into internal physiological processes. Mice, with discernible facial responses and evolutionarily conserved mammalian facial movement control circuits, provide an ideal model to unravel the link between facial movement and internal physiological states in mammals. However, existing frameworks lack the spatial or temporal resolution to track motion of the entire mouse face, due to its small and conical form factor. We introduce Cheese3D, a computer vision system that first captures high-speed 3D motion of the entire mouse face (including ears, eyes, whisker pad, jaw, while covering both sides of the face) using a calibrated six-camera array. The interpretable framework extracts dynamics of anatomically-meaningful 3D facial features in absolute world units at sub-millimeter precision. The precise face-wide motion data generated by Cheese3D provides clear physiological insights, as shown by proof-of-principle experiments predicting time under anesthetic from subtle facial patterns, and inferring tooth and muscle anatomy from fast chewing motions. Cheese3D can serve as a discovery tool that renders facial movements highly interpretable as a read-out of otherwise hidden internal states.
Profiling genetically driven alternative splicing across the Indonesian Archipelago
Authors: Ibeh Neke , Kusuma Pradiptajati , Crenna Darusallam Chelzie , Malik Safarina , Sudoyo Herawati , McCarthy Davis J. , Romero Irene Gallego
Published: May 2024

One of the regulatory mechanisms influencing the functional capacity of genes is alternative splicing (AS). Previous studies exploring the splicing landscape of human tissues have shown that AS has contributed to human biology, especially in disease progression and the immune response. Nonetheless, this phenomenon remains poorly characterised across human populations, and it is unclear how genetic and environmental variation contribute to alternative splicing. Here, we examine a set of 115 Indonesian samples from three traditional island populations spanning the genetic ancestry cline that characterizes Island Southeast Asia. We conduct a global AS analysis between islands to ascertain the degree of functionally significant AS events and their consequences. Using a hierarchical event-based statistical model, we detected over 1,000 significant differential AS events across all comparisons. Additionally, we identify over 6,000 genetic variants associated with changes in splicing (splicing quantitative trait loci; sQTLs), some of which are driven by Papuan-like genetic ancestry, and only show partial overlap with other publicly available sQTL datasets derived from other populations. Computational predictions of RNA binding activity revealed that a fraction of these sQTLs directly modulate the binding propensity of proteins involved in the splicing regulation of immune genes. Overall, these results contribute towards elucidating the role of genetic variation in shaping gene regulation in one of the most diverse regions in the world.
Feasibility of a strong focusing synchrotron for cold neutron beams
Authors: Lee S. Y. , Nguyen L. K.
Published: May 2024

We study the feasibility of storing cold neutron beams in a strong focusing synchrotron. We also propose an alternating-current (ac) dipole magnet to be used as a neutron acceleration device and a pulsed quadrupole as a neutron beam kicker for injection and extraction. The ac acceleration device can provide adiabatic capture, acceleration, or deceleration of neutron beams. It seems feasible to design a high-quality neutron synchrotron for many future neutron beam applications, such as neutron life time measurements, monoenergetic neutron scattering experiments, and pencil neutron beam applications. This synchrotron can also be used as an injector for a neutron accumulator ring.

Published by the American Physical Society
2024
Tuning superconductivity and spin-vortex instabilities in
CaKFe4As4
through in-plane antisymmetric strains
Authors: Valadkhani Adrian , Céspedes Belén Zúñiga , Mandloi Salony , Xu Mingyu , Schmidt Juan , Bud'ko Sergey L. , Canfield Paul C. , Valentí Roser , Gati Elena
Published: May 2024

Lattice strains of appropriate symmetry have served as an excellent tool to explore the interaction of superconductivity in the iron-based superconductors with orthorhombic-nematic and stripe spin-density-wave (SSDW) order. In this Letter, we contribute to a broader understanding of the coupling of strain to superconductivity and competing normal-state orders by studying CaKFe4As4 under large, in-plane strains of B1g and B2g symmetry. In contrast to the majority of iron-based superconductors, pure CaKFe4As4 exhibits superconductivity with a relatively high transition temperature of Tc∼35K in proximity of a noncollinear, tetragonal, hedgehog spin-vortex crystal (SVC) order. Through experiments and calculations, we demonstrate an anisotropic in-plane strain response of Tc and the favored SVC configuration in CaKFe4As4. This supports a scenario, in which the change in spin fluctuations dominates the strain response of superconducting Tc. Overall, by suggesting moderate B2g strains as an effective parameter to change the stability of SVC and SSDW, we outline a pathway to a unified phase diagram of iron-based superconductivity.

Published by the American Physical Society
2024
Energy hierarchies governing quarkonium dynamics in heavy ion collisions
Authors: Sharma Rishi , Singh Balbeer
Published: May 2024

In this paper, we critically examine hierarchies between the energy scales that determine quarkonium dynamics in the quark gluon plasma. A particularly important role is played by the ratio of the binding energy of species (Eb) and the medium scales; temperature (T) and Debye mass (mD). It is well known that if these ratios are much larger than 1 then the dominant process governing quarkonium evolution is dissociation by thermal gluons (gluodissociation). On the other hand, if the ratio Eb/T is much smaller than one then quarkonium dynamics is dominated by screening and Landau damping of the exchanged gluons. Here we show that over most of the evolution, the scale hierarchies do not fall in either limit and one needs to use the full structure of the gluonic spectral function to follow the dynamics of the QQ¯ pair. This has a significant bearing when we follow the quantum dynamics of quarkonia in the medium. The inverse medium relaxation time is also ≈T and if Eb is comparable (or larger) in magnitude to T, the quantum evolution of QQ¯ is nonlocal in time within the Brownian approximation.

Published by the American Physical Society
2024
Breaking and resurgence of symmetry in the non-Hermitian Su-Schrieffer-Heeger model in photonic waveguides
Authors: Slootman E. , Cherifi W. , Eek L. , Arouca R. , Bergholtz E. J. , Bourennane M. , Smith C. Morais
Published: May 2024

Symmetry is one of the cornerstones of modern physics and has profound implications in different areas. In symmetry-protected topological systems, symmetries are responsible for protecting surface states, which are at the heart of the fascinating properties exhibited by these materials. When the symmetry protecting the edge mode is broken, the topological phase becomes trivial. By engineering losses that break the symmetry protecting a topological Hermitian phase, we show that a new genuinely non-Hermitian symmetry emerges, which protects and selects one of the boundary modes: the topological monomode. Moreover, the topology of the non-Hermitian system can be characterized by an effective Hermitian Hamiltonian in a higher dimension. To corroborate the theory, we experimentally investigated the non-Hermitian one- and two-dimensional SSH models using photonic lattices and observed dynamically generated monomodes in both cases. We classify the systems in terms of the (non-Hermitian) symmetries that are present and calculate the corresponding topological invariants.

Published by the American Physical Society
2024
High-Order Randomized Compiler for Hamiltonian Simulation
Authors: Nakaji Kouhei , Bagherimehrab Mohsen , Aspuru-Guzik Alán
Published: May 2024

Hamiltonian simulation is known to be one of the fundamental building blocks of a variety of quantum algorithms such as its most immediate application, that of simulating many-body systems to extract their physical properties. In this work, we present qSWIFT, a high-order randomized algorithm for Hamiltonian simulation. In qSWIFT, the required number of gates for a given precision is independent of the number of terms in the Hamiltonian, while the systematic error is exponentially reduced with regard to the order parameter. In this respect, our qSWIFT is a higher-order counterpart of the previously proposed quantum stochastic drift protocol (qDRIFT), the number of gates in which scales linearly with the inverse of the precision required. We construct the qSWIFT channel and establish a rigorous bound for the systematic error quantified by the diamond norm. qSWIFT provides an algorithm to estimate given physical quantities by using a system with one ancilla qubit, which is as simple as other product-formula-based approaches such as regular Trotter-Suzuki decompositions and qDRIFT. Our numerical experiment reveals that the required number of gates in qSWIFT is significantly reduced compared to qDRIFT. In particular, the advantage is significant for problems where high precision is required; e.g., to achieve a systematic relative propagation error of 10−6, the required number of gates in third-order qSWIFT is 1000 times smaller than that of qDRIFT.

Published by the American Physical Society
2024
Understanding the link between supervisor and co-worker support, job characteristics, work engagement and employee resilience: evidence from Uganda
Authors: Nabawanuka Hamidah , Ekmekcioglu Emre Burak
Published: May 2024

Purpose

The purpose of this study is to investigate the relationship between support (i.e. supervisor support (SS) and co-worker support (CS)), job characteristics (job autonomy, job complexity and skill variety) and work engagement (WE). Furthermore, the study examined whether there is a mediating effect of employee resilience (ER) on the aforementioned variables.

Design/methodology/approach

Data were collected from employees working in SMEs in Uganda. A sample of 324 responses was used for data analysis. Structural equation modelling and bootstrapping procedures were used to test the hypothesized relationships.

Findings

The study findings confirmed that SS, CS and job characteristics were positively related to WE. The study revealed that SS, job autonomy, job complexity and skill variety were found to foster WE through ER. Yet, CS was found not to have an indirect impact on WE through ER.

Research limitations/implications

Because this study was conducted using a cross-sectional research methodology, it makes it hard to draw causal inferences.

Originality/value

This study’s findings contribute to the existing body of literature on WE and job characteristics and also adds to the growing body of research on ER.
Knowledge management drivers and its results: a quantitative study in a public higher education institution
Authors: Alves Juliano Nunes , Cogo Moisés Pivetta , Klein Leander Luiz , Pereira Breno Augusto Diniz
Published: May 2024

Purpose

The purpose of this study was to evaluate the influence of knowledge management (KM) drivers on perceived KM results in a public higher education institution. A structured theoretical model based on leadership, people, processes, knowledge processes, technology, learning and KM results was developed and tested.

Design/methodology/approach

A survey was conducted with the employees of a public higher education institution where an administrative reform was initiated. A valid sample of 257 respondents was obtained. The data were obtained from the application of a structured questionnaire based on the KM drivers and their results. A five-point Likert-type scale was used to measure respondents' answers. The main data analysis technique was structural equation modeling.

Findings

The results indicate knowledge processes, leadership and people factors have a positive and significant impact on KM results. On the other hand, organizational processes, technology and learning factors were not significant. However, the service length of servants in the institution influences the perception of knowledge drivers.

Practical implications

Public institutions should be attentive to people with more time of service because they may have difficulties with technological advances, reorganization of processes and adaptation to new ways of sharing knowledge.

Originality/value

This study advances on the analysis of KM results in the public sector and tests the moderation effect of time of service.
Knowledge sharing and NPD performance for UK cross – border M&A firms: the moderating role of behavior and outcome controls
Authors: Lee Hanna , Um Ki-Hyun
Published: May 2024

Purpose

This paper aims to explore how the effect of knowledge sharing through mergers and acquisitions (M&As) on new product development (NPD) performance is contingent upon two different types of control mechanisms: behavior control and outcome control.

Design/methodology/approach

Leveraging the theory from transaction cost economics, this study provides answers regarding the roles of behavior and outcome controls. The hypotheses were tested empirically across a sample of 143 UK cross-border M&A firms.

Findings

The results provide the increasing call for an integrative perspective and theory in the M&A literature in that knowledge sharing through M&As is deemed decisive for NPD performance, and while both control mechanisms are effective, behavior control is more effective in enhancing NPD performance than outcome control.

Originality/value

The relevant M&A studies lack insights into the use of control mechanisms as a way to monitor the target firm’s behavior and performance and reduce the risk of its opportunistic behavior. Appreciating the need for M&A literature that elaborates control strategy and structure, this study incorporates behavior control and outcome control into M&A mechanisms.
Medical secretaries’ fears and opportunities in an increasingly digitalised workplace environment
Authors: Qvarfordt Maria , Lagrosen Stefan , Nilsson Lina
Published: May 2024

Purpose

The purpose of this mixed-methods study was to explore how medical secretaries experience digital transformation in a Swedish healthcare organisation, with a focus on workplace climate and health.

Design/methodology/approach

Data were collected using a sequential exploratory mixed-methods design based on grounded theory, with qualitative data collection (a Quality Café and individual interviews) followed by quantitative data collection (a questionnaire).

Findings

Four categories with seven underlying factors were identified, emphasising the crucial need for effective organisation of digital transformation. This is vital due to the increased knowledge and skills in utilising technology. The evolving roles and responsibilities of medical secretaries in dynamic healthcare settings should be clearly defined and acknowledged, highlighting the importance of professionality. Ensuring proper training for medical secretaries and other occupations in emerging techniques is crucial, emphasising equal value and knowledge across each role. Associations were found between some factors and the health of medical secretaries.

Research limitations/implications

This study adds to the knowledge on digital transformation in healthcare by examining an important occupation. Most data were collected online, which may be a limitation of this study.

Practical implications

Several aspects of the medical secretaries’ experiences were identified. Knowledge of these is valuable for healthcare managers to make digital transformation more effective while avoiding excessive strain on medical secretaries.

Originality/value

Medical secretaries are expected to contribute to the digitalisation of healthcare. However, minimal research has been conducted on the role of medical secretaries in workplace digitalisation, focusing on workplace roles and its dynamics.
CIV-MIL integration in the transformation of the EU healthcare network: a dual-gain strategy
Authors: Frassini Jacopo
Published: May 2024

Purpose

This article aims to address the need for a more structured partnership between civilian and military healthcare, particularly in the context of cross-border threats in the EU. While both systems are driven by the same goal of providing high-quality healthcare services and achieving optimal patient outcomes, they operate under different national approaches and resources.

Design/methodology/approach

Two recent crises are presented as examples that highlight the necessity of cooperation between civilian and military medical systems. The Covid-19 Pandemic and the Ukrainian Conflict are described based on the experience gathered by the author as a member of the NATO Centre of Excellence for Military Medicine and form the base to shape a broader perspective on the future of civil-military interaction in healthcare at the European Union level.

Findings

The ability to deliver coordinated responses during crises depend on the level of interoperability, preparation and mutual understanding. To improve synergies, a structured partnership should be established, prioritizing common standards of care and shared best practices. Integrating military and civilian healthcare pathways can be especially beneficial in situations where patients are moved from the point of injury or sickness across different military and civilian structures to receive the most appropriate treatment and rehabilitation for their conditions.

Originality/value

The relationship between military and civilian healthcare systems is often discussed at multinational level, but a clear focus is lacking concerning their shared mission, distinct functions and potential for cross-border collaboration.
Exploring the linkages among green digital transformation capability, ambidextrous green learning and sustainability performance: a case study of manufacturing firms in Taiwan
Authors: Huang Chih-Hsuan , Huang Yi-Chun
Published: May 2024

Purpose

This study proposes an innovative concept of green digital transformation capability (GDTC) and explores the interrelationships among GDTC, ambidextrous green learning (AGL) and sustainability performance (SP) from multiple perspectives.

Design/methodology/approach

Survey questionnaires were distributed to Taiwanese firms engaged in various sectors, including electrical and information, metal and precision machinery, rubber material, chemical, daily necessity and food and beverage manufacturing, resulting in 306 valid responses. Structural equation modeling in SPSS v26 was used to test the hypotheses. Furthermore, we analyzed the mediating effects using SPSS PROCESS.

Findings

The results demonstrated that GDTC affected SP both directly and indirectly through exploratory and exploitative green learning. Furthermore, this study revealed the pathways through which GDTC influenced the SP of Taiwanese manufacturing firms.

Research limitations/implications

This study is limited to Taiwanese manufacturing firms. Future studies should expand their sample size to explore digital transformation (DT) practices in various regions and industries.

Social implications

The DTs in manufacturing have profound social implications, emphasizing that companies should consider economic, social and environmental sustainability during digitalization.

Originality/value

This study introduces a novel concept of GDTC and provides important theoretical insights and practical implications for the intersection of DT and sustainability perspective. These findings will offer valuable guidance to companies seeking sustainable development in the digital era.
Navigating political minefields: applying frames of reference of the employment relation to access negotiations to workplace ethnographies
Authors: Stefan Jana , Hirst Alison , Guerci Marco , Toraldo Maria Laura
Published: May 2024

Purpose

This paper aims to help workplace ethnographers navigate and reflect on primary access negotiations by scrutinising two of the concepts mentioned in the call for papers on this special issue: workplace relations and tensions. We introduce the frames of reference (FoRs) concept as used in the field of employment relations to the ethnographic community. We propose that the implicit frames of gatekeeper and researcher influence what they deem interesting for research, thus influencing the content of access negotiations. Moreover, we propose that tensions typically emerge when gatekeepers and ethnographers do not share the same frame of the employment relationship (ER).

Design/methodology/approach

We explore the ER through Fox’s (1966, 1974) framework, taking inspiration from Budd et al. (2022), who applied FoRs to employer–employee relations. We adapt the framework to the relationships between workplace ethnographers and gatekeepers by theorising the characteristics of ideal types of gatekeepers and workplace ethnographers and exploring possible implications for when they meet in access negotiations. We distil lessons learnt from previous research by drawing on illustrative examples from the literature to suggest strategies for interacting with gatekeepers when tensions emerge, providing a pragmatic application of our contribution.

Findings

Assuming that their FoR of the ER contributes to what they find to be of practical relevance/academic interest, we suggest that a (mis)match of gatekeepers’ and workplace ethnographers’ FoRs can lead to tensions between workplace ethnographers and gatekeepers, either remaining latent or becoming salient. We propose three possible strategies as to how to navigate these tensions during primary access negotiations.

Originality/value

Whilst previous research has mainly focused on the ethnographer as an individual who needs to give gatekeepers a reassuring and enticing impression, we discuss how an important structural factor, an organisation’s ER setup, may influence access. We thus bring an important yet hitherto neglected aspect of organisational life into the debate on the pragmatic realities of ethnography, contributing to the discussion of how to navigate the tension between the “practical” need to convince gatekeepers and the need to fulfil one’s own standards of rigorous research and ethics.