bluuebunny/crossref_metadata_2025 huggingface dataset:
Normative Growth Modeling of Cortical Thickness Identify Neuroanatomical Variability and Distinct Subtypes in Brainstem Tumor Patients
Authors: Jia Heyuan , Wang Kaikai , Zhang Peng , Zhang Mingxin , Mai Yiying , Chu Congying , Yin Xuntao , Fan Lingzhong , Zhang Liwei
Published: August 2024

Background

Brainstem tumors can cause structural brain changes, but the resulting heterogeneity within wholebrain structure is not well-studied. This study examines cortical thickness to identify patterns of structural alterations and explore underlying biological subtypes and their associations with clinical factors.

Materials and Methods

This study involved 124 pediatric brainstem tumor patients, aged 4-18 years. Cortical thickness was measured using CAT12 segmentation of 3D T1-weighted structural MRI. A normative model was established using data from 849 healthy children. Deviations in cortical thickness were estimated, and patients were classified into two subtypes using spectral clustering. Clinical statistical analyses were conducted with SPSS 26.0.

Results

The normative model revealed significant heterogeneity in cortical thickness deviations, which correlated with tumor size and growth patterns. Focal tumors primarily caused negative deviations (t = 3.14, p = 0.02). There was a significant positive correlation between extreme positive deviations and tumor volume (r = 0.214, p = 0.010), and between extreme negative deviations and progression-free survival (r = 0.39, p = 0.008). Two subtypes were identified: Subtype 1, consisting of diffuse tumors with extreme positive deviations, and Subtype 2, consisting of focal tumors with extreme negative deviations. Subtype and tumor growth pattern significantly influenced duration (p < 0.01). The Kaplan-Meier survival curves for Subtype 1 and Subtype 2 demonstrated a significant difference in survival probabilities over time (p = 0.03).

Conclusion

Overall, this study identifies two major patterns of cortical thickness changes in brainstem tumor patients, enhancing our understanding of their relationship with cortical morphology. The findings suggest that cortical thickness alterations could serve as valuable biomarkers for predicting progression-free survival, which is crucial for clinical assessment and personalized treatment strategies. This research provides new insights into the physiological mechanisms by which brainstem tumors affect brain structure, supporting more precise clinical interventions and efficacy monitoring in the future.
Fertility Transition in India, 1985-2020: Selection of the Aggregation Function Matters
Authors: Chaurasia Aalok Ranjan
Published: August 2024

This paper analyses fertility transition in India during 1985-2020 based on the data from the official sample registration system. The analysis reveals that fertility transition in the country is contingent upon the way age-specific fertility rates are aggregated into a single composite indicator of fertility. When the simple arithmetic mean of age-specific fertility rates is used as a composite indicator of fertility, fertility in India has decreased almost linearly. However, when the geometric mean of age-specific fertility rates is used as the composite indicator of fertility, fertility transition in India appears to have stalled the period 2011-2013. The analysis also reveals that the change in marital fertility accounted for only about 35 per cent of the change in the simple arithmetic mean of age-specific fertility rates but more than half of the change in the geometric mean of age-specific fertility rates. The paper suggests that fertility transition should not be analysed in terms of the trend in the simple arithmetic mean of age-specific fertility rates or, equivalently, total fertility rate but should be analysed in terms of the trend in the geometric mean of age-specific fertility rates.
Perceptual super-resolution in multiple sclerosis MRI
Authors: Giraldo Diana L. , Khan Hamza , Pineda Gustavo , Liang Zhihua , Lozano Alfonso , Wijmeersch Bart Van , Woodruff Henry C. , Lambin Philippe , Romero Eduardo , Peeters Liesbet M. , Sijbers Jan
Published: August 2024

Magnetic resonance imaging (MRI) is crucial for diagnosing and monitoring of multiple sclerosis (MS) as it is used to assess lesions in the brain and spinal cord. However, in real-world clinical settings, MRI scans are often acquired with thick slices, limiting their utility for automated quantitative analyses. This work presents a single-image super-resolution (SR) reconstruction framework that leverages SR convolutional neural networks (CNN) to enhance the through-plane resolution of structural MRI in people with MS (PwMS). Our strategy involves the supervised fine-tuning of CNN architectures, guided by a content loss function that promotes perceptual quality, as well as reconstruction accuracy, to recover high-level image features. Extensive evaluation with MRI data of PwMS shows that our SR strategy leads to more accurate MRI reconstructions than competing methods. Furthermore, it improves lesion segmentation on low-resolution MRI, approaching the performance achievable with high-resolution images. Results demonstrate the potential of our SR framework to facilitate the use of low-resolution retrospective MRI from real-world clinical settings to investigate quantitative image-based biomarkers of MS.
Alzheimer's Disease Classification Confidence of Individuals using Deep Learning on Heterogeneous Data
Authors: Alausa Afolabi Salami , Sanchez-Bornot Jose M , Asadpour Abdoreza , McClean Paula L , Wong-Lin KongFatt
Published: August 2024

Making accurate diagnosis of Alzheimer's disease (AD) is crucial for effective treatment and management. Although deep learning has been applied to AD classification, it is typically performed at group level, the data used are not sufficiently heterogeneous and comprehensive, and decision confidence is not evaluated at individual (single patient) level. This paper proposed a more practical deep learning approach that not only detects AD stages of individuals, but also provides its corresponding confidence estimation. In particular, in addition to a convolutional neural network (CNN), we incorporated a softmax confidence metric based on the network's output activity to evaluate its classification confidence. Further, we applied this approach to a heterogeneous and comprehensive data that comprised cognitive and functional assessments, tau-PET and MRI neuroimaging, medical/family history, demographic, and APoE genotype. Importantly, we utilised leave-one-out cross-validation to train the CNN and classify an individual's healthy control, mild cognitive impairment or AD state, while concurrently estimating each output decision's confidence. We showed that, over different confidence softmax temperature values, CNN could attain classification accuracies at 83-85% for the three classes while having robust confidence scores of 78-83%. Further improvement in confidence breakdown was achieved using the optimal temperature value in confidence evaluation, with higher confidence scores for correct than error decisions. Overall, the computed classification confidence of an individual may aid clinicians and other stakeholders in understanding the reliability of the model's decision outcome and offer better trust. The implication of this work may extend to other classification applications, in which the confidence level of a single deep learning-based decision can be evaluated.
Optimization and performance analytics of global aircraft-based wastewater surveillance networks
Authors: St-Onge Guillaume , Davis Jessica T. , Hébert-Dufresne Laurent , Allard Antoine , Urbinati Alessandra , Scarpino Samuel V. , Chinazzi Matteo , Vespignani Alessandro
Published: August 2024

Aircraft wastewater surveillance has been proposed as a novel approach to monitor the global spread of pathogens. Here we develop a computational framework to provide actionable information for designing and estimating the effectiveness of global aircraft-based wastewater surveillance networks (WWSNs). We study respiratory diseases of varying transmission potentials and find that networks of 10 to 20 strategically placed wastewater sentinel sites can provide timely situational awareness and function effectively as an early warning system. The model identifies potential blind spots and suggests optimization strategies to increase WWSNs effectiveness while minimizing resource use. Our findings highlight that increasing the number of sentinel sites beyond a critical threshold does not proportionately improve WWSNs capabilities, stressing the importance of resource optimization. We show through retrospective analyses that WWSNs can significantly shorten the detection time for emerging pathogens. The presented approach offers a realistic analytic framework for the analysis of WWSNs at airports.
Shared Genetic Liability across Systems of Psychiatric and Physical Illness
Authors: Lawrence Jeremy M. , Foote Isabelle F. , Breunig Sophie , Schaffer Lukas S. , Mallard Travis T. , Grotzinger Andrew D.
Published: August 2024

Epidemiological literature has shown that there are extensive comorbidity patterns between psychiatric and physical illness. However, our understanding of the multivariate systems of relationships underlying these patterns is poorly understood. Using Genomic SEM and Genomic E-SEM, an extension for genomic exploratory factor analysis that we introduce and validate, we evaluate the extent to which latent genomic factors from eight domains, encompassing 76 physical outcomes across 1.9 million cases, evince genetic overlap with previously identified psychiatric factors. We find that internalizing, neurodevelopmental, and substance use factors are broadly associated with increased genetic risk sharing across all physical illness domains. Conversely, we find that a compulsive factor is protective against circulatory and metabolic illness, whereas genetic risk sharing between physical illness factors and psychotic/thought disorders was limited. Our results reveal pervasive risk sharing between specific groups of psychiatric and physical conditions and call into question the bifurcation of psychiatric and physical conditions.
Associations between genetic HPV 16 diversity and cervical cancer prognosis
Authors: Patury Patrícia , Russomano Fábio B. , Martins Luiz F.L. , Moreira Miguel Angelo Martins , Carvalho Raquel B.M. , Kappaun Nádia R. C. , de Almeida Liz Maria
Published: August 2024

Introduction

Cervical cancer (CC) arises as a result of chronic and persistent female genitalia infection by different oncogenic human papillomaviruses (HPV). The incidence of this disease is still high in developing countries such as Brazil, where the diagnosis is often made in advanced stages. HPV 16 is the most common type of CC worldwide. Studies concerning the association of different HPV 16 lineages with overall and disease-free CC survival rates can contribute to further understanding the behavior of different HPV 16 lineages concerning the prognosis of CC cases.

Objective

Assess the CC prognosis of patients treated in a Brazilian institution with regard to HPV16 strains.

Methods

Data were obtained from a prospective cohort of 334 CC patients recruited between July 2011 and March 2014 and treated at the Brazilian National Cancer Institute (INCA), in Rio de Janeiro, Brazil. HPV 16 lineages were identified in tumor tissue samples. Genetic HPV 16 diversity comprised 218 cases of lineage A, 10 of lineage B, 10 of lineage C and 96 of lineage D. In addition to HPV 16 lineages, age, histopathological type, staging, and treatment completion were evaluated regarding CC prognosis.

Results

Median patient age was 48 years old. The most common histopathological type was squamous cell carcinoma (82.3%), followed by adenocarcinoma. Locally advanced disease staging was the most frequently detected, represented by similar stage II and III percentages (36.2% and 37.7%), followed by initial stage I (19.2%) and stage IV presenting distant disease (6.9%). Only 187 patients completed CC treatment. Age, histological type, staging, and treatment completion were associated with a higher risk of death, which was not observed for the HPV 16 lineage variable. With regard to age, each one year of life increase led to about a 1% increase in risk of death. Other histopathological types (poorly differentiated carcinoma, adenosquamous, neuroendocrine and sarcoma) were associated with a higher risk of death compared to adenocarcinoma. Squamous cell carcinoma also represented a higher risk of death compared to adenocarcinoma, albeit non-statistically significant. Patients diagnosed in advanced stages exhibited a higher risk of death, and those who did not complete treatment exhibited an over 2-fold increased risk of death.

Conclusion

This study found no associations between HPV 16 lineages A, B, C and D and CC prognosis.
A new clade of pararetroviruses distantly related to hepadnaviruses and nackednaviruses
Authors: Buigues Jaime , Viñals Adrià , Martínez-Recio Raquel , Monrós Juan S. , Cuevas José M. , Sanjuán Rafael
Published: August 2024

Group VII of the Baltimore classification comprises reverse-transcribing, non-integrated DNA viruses, also known as pararetroviruses. These include the hepadnaviruses, a family of small enveloped DNA viruses that infect vertebrates, but also a sister family of non-enveloped fish viruses, the nackednaviruses. Here we describe the complete sequence of a new pararetrovirus found in the feces of an insectivorous bat. This virus encodes a core protein and a reverse transcriptase but no envelope protein. A database search identified a viral sequence from a permafrost sample as its closest relative. The two viruses form a cluster that occupies a basal phylogenetic position relative to hepadnaviruses and nackednaviruses, with an estimated divergence time of 500 million years. These findings may lead to the definition of a new viral family and support the hypothesis that ancestral animal pararetroviruses were non-enveloped.
Microcystins are critical for the toxicMicrocystisto survive long-term nitrogen starvation
Authors: Lian Xiao-Ya , Qiu Guo-Wei , Zheng Wen-Can , Shang Jin-Long , Xu Hai-Feng , Dai Guo-Zheng , Gan Nan-Qin , Zhang Zhong-Chun , Qiu Bao-Sheng
Published: August 2024

Toxic cyanobacterial blooms have expanded and intensified on a global scale, but the physiological role of microcystins during bloom development is not fully resolved. Here, we show that microcystin production can increase the survival and resuscitation rate ofMicrocystisafter long-term nitrogen starvation. Our results showed that microcystin production could enable toxicMicrocystisto accumulate more carbon reserves under nitrogen limitation, which is critical to support the survival of cells under stressful conditions. Further analysis showed that genes involved in microcystin synthesis were significantly upregulated at the initial phase of recovery, which could help toxicMicrocystisto strengthen glycogen catabolism and fuel recovery. The close genetic traits betweenMicrocystisstrains suggest the strategies observed here might be highly conserved. Our findings imply how toxicMicrocystisestablish a competitive advantage over non-toxic species and provide new insight into the seasonal dynamic of theMicrocystispopulation in natural environment.

IMPORTANCE

Microcystins are the most abundant cyanotoxins released during harmful algal blooms. While the factors controlling microcystin production have been widely studied, the function of these toxic secondary metabolites under changing environments remains poorly understood. Here we proved that microcystins are critical to toxicMicrocystisto maintaining carbon metabolism under long-term nitrogen starvation and subsequent recovery. Compared to the non-toxic strains, microcystin-producingMicrocystisexhibit a higher viability and resuscitation rate after prolonged nitrogen starvation, which is consistent with the dominance of these species at the early stage of cyanobacterial blooms. Our findings shed light on the genetic traits that drive population succession during bloom development, which is important for the modeling and prediction of harmful cyanobacterial blooms.
Transcriptomic Meta-analysis Identifies Long Non-Coding RNAs Mediating Zika’s Oncolytic Impact in Glioblastoma Multiforme
Authors: Kousa Youssef A. , Singh Shriya , Horvath Allison , Tomasso Federica , Nazarian Javad , Henderson Lisa , Mansour Tamer A.
Published: August 2024

Glioblastoma multiforme (GBM) is an aggressive and lethal form of brain cancer with few effective treatments. In this context, Zika virus has emerged as a promising therapeutic agent due to its ability to selectively infect and kill GBM cells. To elucidate these mechanisms and expand the landscape of oncolytic virotherapy, we pursued a transcriptomic meta-analysis comparing the molecular signatures of Zika infection in GBM and neuroblastoma (NBM). Over-representation analysis of dysregulated coding genes showed significant enrichment of tumor necrosis factor (TNF), NF-κB, and p53 signaling pathways. A refined list of long non-coding RNAs consistently dysregulated in Zika-infected GBMs was also developed. Functional review of these candidates revealed their potential regulatory role in Zika-mediated oncolysis. We performed validation of the less-researched targets in adult and pediatric GBM cell lines and found significant differential regulation, as predicted. Altogether, our results provide novel insights into the molecular mechanisms underlying the effect of Zika on GBM. We highlight potential therapeutic targets that could be further interrogated to improve the efficacy of tumor cell death and the utility of Zika as an adjuvant virotherapy for GBM and other related cancers.
Differential regulation of BAX and BAK apoptotic activity revealed by a novel small molecule
Authors: Li Kaiming , Yap Yu Q. , Moujalled Donia M. , Sumardy Fransisca , Khakham Yelena , Georgiou Angela , Jahja Michelle , Lew Thomas E. , De Silva Melanie , Luo Meng-Xiao , Gong Jia-nan , Roberts Andrew W. , Yuan Zheng , Birkinshaw Richard W. , Czabotar Peter E. , Lowes Kym , Huang David C. S. , Kile Benjamin T. , Wei Andrew H. , Dewson Grant , van Delft Mark F. , Lessene Guillaume
Published: August 2024

Defective apoptosis mediated by BAK or BAX underlies various human pathologies including autoimmune and degenerative conditions. The mitochondrial channel protein VDAC2 interacts with BAK and BAX through a common interface to either inhibit BAK or to facilitate BAX apoptotic activity. Using a newly developed small molecule (WEHI-3773) that inhibits the interaction between VDAC2 and BAK or BAX, we reveal contrasting effects on BAX and BAK apoptotic activity. WEHI-3773 inhibits apoptosis mediated by BAX by blocking VDAC2-mediated BAX recruitment to mitochondria. Conversely, WEHI-3773 primes BAK for apoptosis by impairing its inhibitory sequestration by VDAC2 on the mitochondrial membrane. In cells expressing both BAX and BAK, repressing their association with VDAC2 promotes apoptosis, because once BAK is activated, it further activates BAX through a feed-forward mechanism. In some leukemias, mutation or loss of BAX is a key driver of resistance to the BH3-mimetic anti-cancer drug venetoclax. Strikingly, promoting BAK-mediated killing by small molecule dissociation of the VDAC2 interaction can overcome this resistance in different leukemia models. These data reveal a hitherto unappreciated level of coordination of BAX and BAK apoptotic activity through their interaction with VDAC2 that may be targeted therapeutically.
Hao-Fountain syndrome protein USP7 controls neuronal differentiation via BCOR-ncPRC1.1
Authors: Wolf van der Meer Joyce , Larue Axelle , van der Knaap Jan A. , Chalkley Gillian E. , Sijm Ayestha , Beikmohammadi Leila , Kozhevnikova Elena N. , van der Vaart Aniek , Tilly Ben C. , Bezstarosti Karel , Dekkers Dick H. W. , Doff Wouter A. S. , van de Wetering-Tieleman P. Jantine , Lanko Kristina , Barakat Tahsin Stefan , Allertz Tim , van Haren Jeffrey , Demmers Jeroen A. A. , Atlasi Yaser , Verrijzer C. Peter
Published: August 2024

Pathogenic variants in the ubiquitin-specific protease 7 (USP7) gene cause a neurodevelopmental disorder called Hao-Fountain syndrome. However, which of USP7’s pleiotropic functions are relevant for neurodevelopment remains unclear. Here, we present a combination of quantitative proteomics, transcriptomics and epigenomics to define the USP7 regulatory circuitry during neuronal differentiation. USP7 activity is required for the transcriptional programs that direct both differentiation of embryonic stem cells into neural stem cells, and the neuronal differentiation of SH-SY5Y neuroblastoma cells. USP7 controls the dosage of the Polycomb H2AK119ub1 ubiquitin ligase complexes ncPRC1.1 and ncPRC1.6. Loss-of-function experiments revealed that BCOR-ncPRC1.1, but not ncPRC1.6, is a key effector of USP7 during neuronal differentiation. Indeed, BCOR-ncPRC1.1 mediates a major portion of USP7-dependent gene regulation during this process. Besides providing a detailed map of the USP7 regulome during neurodifferentiation, our results suggest that USP7 and ncPRC1.1-associated neurodevelopmental disorders involve dysregulation of a shared epigenetic network.
Compensating slice emittance growth in high brightness photoinjectors using sacrificial charge
Authors: Li W. H. , Bartnik A. C. , Fukasawa A. , Kaemingk M. , Lawler G. , Majernik N. , Rosenzweig J. B. , Maxson J. M.
Published: August 2024

Achieving maximum electron beam brightness in photoinjectors requires detailed control of the 3D bunch shape and precise tuning of the beam focusing. Even in state-of-the-art designs, slice emittance growth due to nonlinear space charge forces and partial nonlaminarity often remains non-negligible. In this work, we introduce a new means to linearize the transverse slice phase space: a sacrificial portion of the bunch’s own charge distribution, formed into a wavebroken shock front by highly nonlinear space charge forces within the gun, whose downstream purpose is to dynamically linearize the desired bunch core. We show that linearization of an appropriately prepared bunch can be achieved via strongly nonlaminar focusing of the sacrificial shock front, while the inner core focuses laminarly. This leads to a natural spatial separation of the two distributions: a dense core surrounded by a diffuse halo of sacrificial charge that can be collimated. Multiobjective genetic algorithm optimizations of the ultracompact x-ray free electron laser injector employ this concept, and we interpret it with an analytic model that agrees well with the simulations. In simulation, we demonstrate a final bunch charge of 100 pC, peak current ∼30 A, and a sacrificial charge of 150 pC (250 pC total emitted from cathode) with normalized emittance growth of <20  nm rad due to space charge. This implies a maximum achievable brightness approximately an order of magnitude greater than existing free electron laser injector designs.

Published by the American Physical Society
2024
Decoherence by warm horizons
Authors: Wilson-Gerow Jordan , Dugad Annika , Chen Yanbei
Published: August 2024

Recently Danielson, Satishchandran, and Wald (DSW) have shown that quantum superpositions held outside of Killing horizons will decohere at a steady rate. This occurs because of the inevitable radiation of soft photons (gravitons), which imprint a electromagnetic (gravitational) “which-path” memory onto the horizon. Rather than appealing to this global description, an experimenter ought to also have a local description for the cause of decoherence. One might intuitively guess that this is just the bombardment of Hawking/Unruh radiation on the system, however simple calculations challenge this idea—the same superposition held in a finite temperature inertial laboratory does not decohere at the DSW rate. In this work we provide a local description of the decoherence by mapping the DSW setup onto a worldline-localized model resembling an Unruh-DeWitt particle detector. We present an interpretation in terms of random local forces which do not sufficiently self-average over long times. Using the Rindler horizon as a concrete example we clarify the crucial role of temperature, and show that the Unruh effect is the only quantum mechanical effect underlying these random forces. A general lesson is that for an environment which induces Ohmic friction on the central system (as one gets from the classical Abraham-Lorentz-Dirac force, in an accelerating frame) the fluctuation-dissipation theorem implies that when this environment is at finite temperature it will cause steady decoherence on the central system. Our results agree with DSW and provide the complementary local perspective.

Published by the American Physical Society
2024
Page curves in holographic superconductors
Authors: Xu Yuanceng , Wang Dong , Pan Qiyuan
Published: August 2024

Considering a doubly holographic model, we study the black hole information paradox for the eternal AdSd-RN black hole coupled to and in equilibrium with a d-dimensional conformal bath whose state has been deformed by the charged scalar field coupled to a U(1) gauge field. Without a brane, the spontaneous symmetry breaking of the gauge field on boundary systems can induce a second-order phase transition of the charged scalar field at the critical temperature, known as holographic superconductors. The bath deformation can significantly change its entanglement dynamics with the black hole, resulting in variations in the Page curve and Page time. Our results indicate that characteristic parameters of the Page curve, such as entanglement velocity, initial area difference and Page time, can be used as suitable probes to detect superconducting phase transitions. In particular, the entanglement velocity can also probe both Kasner flows and Josephson oscillations. When keeping the endpoint of the radiation region fixed at twice the critical Page point, the entanglement velocity (the internal backreaction) has a more significant influence on the Page time compared to the initial area difference (the external backreaction).

Published by the American Physical Society
2024
Rotational holographic transport from Kerr-Newman-AdS black hole
Authors: Meert Pedro , Nastase Horatiu
Published: August 2024

We consider rotational holographic transport in strongly coupled 2+1-dimensional systems, from the point of view of 3+1-dimensional gravity. We consider the moment of inertia I as a kind of transport coefficient, identified with the moment of inertia of a charged rotating black hole in AdS4 background. In the low-temperature region, we find the behavior of the density I/A with temperature T and angular velocity Ω and find a quadratic behavior for

∂

(

I

/

A

)

/

∂

Ω

with T, in the presence of some charge Q.

Published by the American Physical Society
2024
Random telegraph processes with nonlocal memory
Authors: Apostolov S. S. , Usatenko O. V. , Yampol'skii V. A. , Melnyk S. S. , Grigolini P. , Krokhin A.
Published: August 2024

We study two-state (dichotomous, telegraph) random ergodic continuous-time processes with dynamics depending on their past. We take into account the history of the process in an explicit form by introducing integral nonlocal memory term into conditional probability function. We start from an expression for the conditional transition probability function describing additive multistep binary random chain and show that the telegraph processes can be considered as continuous-time interpolations of discrete-time dichotomous random sequences. An equation involving the memory function and the two-point correlation function of the telegraph process is analytically obtained. This integral equation defines the correlation properties of the processes with given memory functions. It also serves as a tool for solving the inverse problem, namely for generation of a telegraph process with a prescribed pair correlation function. We obtain analytically the correlation functions of the telegraph processes with two exactly solvable examples of memory functions and support these results by numerical simulations of the corresponding telegraph processes.

Published by the American Physical Society
2024
Origin of Magnetism in a Supposedly Nonmagnetic Osmium Oxide
Authors: Agrestini S. , Borgatti F. , Florio P. , Frassineti J. , Fiore Mosca D. , Faure Q. , Detlefs B. , Sahle C. J. , Francoual S. , Choi J. , Garcia-Fernandez M. , Zhou K.-J. , Mitrović V. F. , Woodward P. M. , Ghiringhelli G. , Franchini C. , Boscherini F. , Sanna S. , Moretti Sala M.
Published: August 2024

A supposedly nonmagnetic 5d1 double perovskite oxide is investigated by a combination of spectroscopic and theoretical methods, namely, resonant inelastic x-ray scattering, x-ray absorption spectroscopy, magnetic circular dichroism, and multiplet ligand-field calculations. We found that the large spin-orbit coupling admixes the 5d t2g and eg orbitals, covalency raises the 5d population well above the nominal value, and the local symmetry is lower than Oh. The obtained electronic interactions account for the finite magnetic moment of Os in this compound and, in general, of 5d1 ions. Our results provide direct evidence of elusive Jahn-Teller distortions, hinting at a strong electron-lattice coupling.

Published by the American Physical Society
2024
Bridging the small and large in twisted transition metal dichalcogenide homobilayers: A tight binding model capturing orbital interference and topology across a wide range of twist angles
Authors: Crépel Valentin , Millis Andrew
Published: August 2024

Many of the important phases observed in twisted transition metal dichalcogenide homobilayers are driven by short-range interactions, which should be captured by a local tight binding description since no Wannier obstruction exists for these systems. Yet, published theoretical descriptions have been mutually inconsistent, with honeycomb lattice tight binding models adopted for some twist angles, triangular lattice models adopted for others, and with tight binding models forsaken in favor of band projected continuum models in many numerical simulations. Here, we derive and study a minimal model containing both honeycomb orbitals and a triangular site that represents the band physics across a wide range of twist angles. The model provides a natural basis to study the interplay of interaction and topology in these heterostructures. It elucidates from generic features of the bilayer the sequence of Chern numbers occurring as twist angle is varied, and the microscopic origin of the magic angle at which flat-band physics occurs. At integer filling, the model successfully captures the Chern ferromagnetic and van Hove-driven antiferromagnetic insulators experimentally observed for small and large angles, respectively, and allows a straightforward calculation of the magnetoelectric properties of the system.

Published by the American Physical Society
2024
Collective rovibronic dynamics of a diatomic gas coupled by cavity
Authors: Krupp Niclas , Vendrell Oriol
Published: August 2024

We consider an ensemble of homonuclear diatomic molecules coupled to the two polarization directions of a Fabry-Pérot cavity via fully quantum simulations. Accompanied by analytical results, we identify a coupling mechanism mediated simultaneously by the two perpendicular polarizations, and inducing polaritonic relaxation towards molecular rotations. This mechanism is related to the concept of light-induced conical intersections (LICIs). However, unlike LICIs, these nonadiabatic pathways are of a collective nature, since they depend on the intermolecular orientation of all electronic transition dipoles in the polarization plane. Notably, this rotational mechanism directly couples the bright upper and lower polaritonic states, and it stays in direct competition with the collective relaxation towards dark states.

Published by the American Physical Society
2024
Photonic cellular automaton simulation of relativistic quantum fields: Observation of
Zitterbewegung
Authors: Suprano Alessia , Zia Danilo , Polino Emanuele , Poderini Davide , Carvacho Gonzalo , Sciarrino Fabio , Lugli Matteo , Bisio Alessandro , Perinotti Paolo
Published: August 2024

Quantum cellular automaton (QCA) is a model for universal quantum computation and a natural candidate for digital quantum simulation of relativistic quantum fields. Here we introduce the first photonic platform for implementing QCA simulation of a free relativistic Dirac quantum field in 1+1 dimension, through a Dirac quantum cellular automaton (DQCA). Encoding the field position degree of freedom in the orbital angular momentum (OAM) of single photons, our state-of-the-art setup experimentally realizes eight steps of a DQCA, with the possibility of having complete control over the input OAM state preparation and the output measurement making use of two spatial light modulators. Therefore, studying the distribution in the OAM space at each step, we were able to reproduce the time evolution of the free Dirac field observing the , an oscillatory movement extremely difficult to see in a real-case experimental scenario that is a signature of the interference of particle and antiparticle states. The accordance between the expected and measured oscillations certifies the simulator performances, paving the way towards the application of photonic platforms to the simulation of more complex relativistic effects.

Published by the American Physical Society
2024
Transport cocktails for cancer therapeutics
Authors: Kavousanakis Michail E. , Bhatavdekar Omkar , Bastiaannet Remco , Kevrekidis Yannis , Sofou Stavroula
Published: August 2024

Beyond biological cell heterogeneity, evidenced by different resistances to therapeutics, “delivery heterogeneity” crucially limits treatment efficacy for advanced solid tumors: variations in therapeutic drug delivery to different tumor areas (perivascular, perinecrotic) leading to nonuniform drug concentrations/doses and to unsuccessful treatment (cancer cell kill). Short-range (40–80 µm), high energy (1–5 MeV) α particles successfully address the biological heterogeneity: the double-strand DNA breaks they cause make them impervious to cell resistance mechanisms. Multiresponsive nanocarriers and/or engineered antibody-drug-conjugates are elegant approaches to delivering such α-particle emitters. Delivery heterogeneity, however, remains a challenge in established (i.e., large, vascularized) tumors. Remarkably, delivery properties enabling efficacy at the cell scale (targeting selectivity, affinity, cell drug uptake) may act against spatial delivery uniformity at the tumor scale (binding-site barrier effect). We have previously demonstrated, in different mouse models, that spatial delivery uniformity, key to the effective killing of solid tumors, can be achieved utilizing combinations of different, distinct delivery carriers of the same emitter, but with different, complementary delivery properties, “leaving no cancer cell behind.” We build first principles reaction-transport models (quantitatively informed by experiments) that explain the “geographically complementary” behaviors of such carrier cocktails, and help optimally design these cocktails and their delivery protocols.

Published by the American Physical Society
2024
Accurate and efficient Bloch-oscillation-enhanced atom interferometry
Authors: Fitzek F. , Kirsten-Siemß J.-N. , Rasel E. M. , Gaaloul N. , Hammerer K.
Published: August 2024

Bloch oscillations of atoms in optical lattices are a powerful technique that can dramatically boost the sensitivity of atom interferometers to a wide range of signals by large momentum transfer. To leverage this method to its full potential, an accurate theoretical description of losses and phases is required, going beyond existing treatments. Here, we present a comprehensive theoretical framework for Bloch-oscillation-enhanced atom interferometry and verify its accuracy through comparison with a numerical solution of the Schrödinger equation. Our approach establishes design criteria to reach the fundamental efficiency and accuracy limits of large momentum transfer using Bloch oscillations and allows us, in a broader context, to define the fundamental efficiency limit of the transport of neutral atoms using optical lattices. We compare these limits to the capabilities of current state-of-the-art experiments and make projections for the next generation of quantum sensors.

Published by the American Physical Society
2024
Cauchy universality and random billiards
Authors: Artuso Roberto , Zamora Dario Javier
Published: August 2024

Motion in bounded domains represents a paradigm in several settings: from billiard dynamics, to random walks in a finite lattice, with applications to relevant physical, ecological, and biological problems. A remarkable universal property, involving the average of return times to the boundary, has been theoretically proposed and experimentally verified in quite different contexts. We discuss here mechanisms that lead to violations of universality, induced by boundary effects and we also emphasize the role played by replacing straight lines with random walks in this framework. We suggest that our analysis should be relevant where nonhomogeneity appears in the stationary probability distribution in bounded domain.

Published by the American Physical Society
2024
From Design to Device: Challenges and Opportunities in Computational Discovery of
p
-Type Transparent Conductors
Authors: Woods-Robinson Rachel , Morales-Masis Monica , Hautier Geoffroy , Crovetto Andrea
Published: August 2024

A high-performance p-type transparent conductor (TC) does not yet exist but could lead to advances in a wide range of optoelectronic applications and enable new architectures for, e.g., next-generation photovoltaic (PV) devices. High-throughput computational material screenings have been a promising approach to filter databases and identify new p-type TC candidates and some of these predictions have been experimentally validated. However, most of these predicted candidates do not have experimentally achieved properties on par with n-type TCs used in solar cells and therefore have not yet been used in commercial devices. Thus, there is still a significant divide between transforming predictions into results that are actually achievable in the laboratory and an even greater lag in scaling predicted materials into functional devices. In this perspective, we outline some of the major disconnects in this materials discovery process—from scaling computational predictions into synthesizable crystals and thin films in the laboratory to scaling laboratory-grown films into real-world solar devices—and share insights to inform future strategies for TC discovery and design.

Published by the American Physical Society
2024
Quantum Computing for High-Energy Physics: State of the Art and Challenges
Authors: Di Meglio Alberto , Jansen Karl , Tavernelli Ivano , Alexandrou Constantia , Arunachalam Srinivasan , Bauer Christian W. , Borras Kerstin , Carrazza Stefano , Crippa Arianna , Croft Vincent , de Putter Roland , Delgado Andrea , Dunjko Vedran , Egger Daniel J. , Fernández-Combarro Elias , Fuchs Elina , Funcke Lena , González-Cuadra Daniel , Grossi Michele , Halimeh Jad C. , Holmes Zoë , Kühn Stefan , Lacroix Denis , Lewis Randy , Lucchesi Donatella , Martinez Miriam Lucio , Meloni Federico , Mezzacapo Antonio , Montangero Simone , Nagano Lento , Pascuzzi Vincent R. , Radescu Voica , Ortega Enrique Rico , Roggero Alessandro , Schuhmacher Julian , Seixas Joao , Silvi Pietro , Spentzouris Panagiotis , Tacchino Francesco , Temme Kristan , Terashi Koji , Tura Jordi , Tüysüz Cenk , Vallecorsa Sofia , Wiese Uwe-Jens , Yoo Shinjae , Zhang Jinglei
Published: August 2024

Quantum computers offer an intriguing path for a paradigmatic change of computing in the natural sciences and beyond, with the potential for achieving a so-called quantum advantage—namely, a significant (in some cases exponential) speedup of numerical simulations. The rapid development of hardware devices with various realizations of qubits enables the execution of small-scale but representative applications on quantum computers. In particular, the high-energy physics community plays a pivotal role in accessing the power of quantum computing, since the field is a driving source for challenging computational problems. This concerns, on the theoretical side, the exploration of models that are very hard or even impossible to address with classical techniques and, on the experimental side, the enormous data challenge of newly emerging experiments, such as the upgrade of the Large Hadron Collider. In this Roadmap paper, led by CERN, DESY, and IBM, we provide the status of high-energy physics quantum computations and give examples of theoretical and experimental target benchmark applications, which can be addressed in the near future. Having in mind hardware with about 100 qubits capable of executing several thousand two-qubit gates, where possible, we also provide resource estimates for the examples given using error-mitigated quantum computing. The ultimate declared goal of this task force is therefore to trigger further research in the high-energy physics community to develop interesting use cases for demonstrations on near-term quantum computers.

Published by the American Physical Society
2024
The corrosion analysis of X80 pipeline steel welded joint using wire beam electrode and numerical simulation methods
Authors: Dou Xiaohui , Li Yadong , Zhang Xinwei , Wang Shengnan , Cheng Yang , Yao Wanpeng , Zhang Dalei , Li Yan
Published: August 2024

Purpose

The purpose of this study is to characterize the galvanic corrosion behavior of a simulated X80 pipeline steel welded joint (PSWJ) reconstructed by the wire beam electrode (WBE) and numerical simulation methods.

Design/methodology/approach

The galvanic corrosion of an X80 PSWJ was studied using WBE and numerical simulation methods. The microstructures of the coarse-grained heat affected zone, fine-grained heat affected zone and intercritical heat affected zone were simulated in X80 pipeline steel via Gleeble thermomechanical simulation processing.

Findings

Comparing the corrosion current density of coupled and isolated weld metal (WM), base metal (BM) and heat-affected zone (HAZ), the coupled WM exhibited a higher corrosion current density than isolated WM; the coupled BM and HAZ exhibited lower corrosion current densities than isolated BM and HAZ. The results exhibited that the maximum anodic galvanic current fitted the Gumbel distribution. Moreover, the numerical simulation results agreed well with the experimental data.

Originality/value

This study provides insight into corrosion evaluation of heterogeneous welded joints by a combination of experiment and simulation. The method of reconstruction of the welded joint has been proven to be a feasible approach for studying the corrosion behavior of the X80 PSWJ with high spatial resolution.
The power control and efficiency optimization strategy of dynamic wireless charging system for multiple electric vehicles
Authors: Zhang Ming , Zhang Hantao , Tao WeiYe , Yang Yan , Sang Yingjun
Published: August 2024

Purpose

This study aims to solve the problem that both the speed and the required driving power of electric vehicles (EVs) will change during the dynamic wireless charging (DWC) process, making it difficult to charge EVs with a constant power considering the overall efficiency of DWC system, the numbers of EVs and the power supply capacity. Therefore, this paper proposes the power control and efficiency optimization strategies for multiple EVs.

Design/methodology/approach

The wireless power charging system for multiple loads with a structure of double-sided LCC compensation topology is established. The expressions of optimal transmission efficiency and optimal equivalent impedance are derived. Taking the Tesla Model 3 as an example, a method to determine the number of EVs allowed by one transmitter coil and the overall charging power is proposed considering EV speed, power supply capacity, safe braking distance and overall efficiency. Then, the power control strategy, which can adapt to the changes of EV speed and the efficiency optimization strategy under different numbers of EVs are proposed.

Findings

In this paper, a method to determine the numbers of EVs allowed by one transmitter coil and the overall charging power is proposed considering EVs speed, power supply capacity, safe braking distance and overall efficiency. The accuracy of the charging power is good enough and the overall efficiency reaches a maximum of 91.79% when the load resistance changes from 5Ω to 20Ω.

Originality/value

In this paper, the power control and efficiency optimization strategy of DWC system for multiple EVs are proposed. Specifically, a method of designing the number of EVs and charging power allowed by one transmitter coil considering the factors of EV speed, power supply capacity, safe braking distance and overall efficiency is designed. The overall efficiency of the experiment reaches a maximum of 91.79% after adopting the optimization strategy.
The measurement of fraud perception of investors and the mediating effect of risk aversion: the case of crypto assets
Authors: Özçelik Musa , Kurt Ganite
Published: August 2024

Purpose

This study aims to gain a new perspective on auditing by measuring investors’ fraud perception and to reveal the necessity of increasing individuals’ fraud perception by determining the effect of fraud perception on the intention to invest in crypto assets from the investor’s perspective.

Design/methodology/approach

As part of this quantitative research, a survey was conducted on individuals residing in Türkiye and aged 18 years and above through a convenience sampling method. A total of 446 participants were included in the study. The data collected was analyzed using the partial least squares-variance based structural equation modeling (PLS-SEM) method using the SmartPLS program.

Findings

Fraud perception causes individuals to be more risk-averse and reduces their intention to invest in crypto assets. At the same time, it has been observed that risk-averse individuals have lower intention to invest in crypto assets. According to the results of the mediating effect analysis, risk aversion behavior partially mediates between the fraud perception and the intention to invest in crypto assets. Among the emotions, only fear increases risk aversion behavior. Among the personality traits, extroversion and openness to experience personality traits reduce risk aversion behavior, whereas neuroticism personality traits increase the intention to invest in crypto assets.

Originality/value

In an environment where traditional auditing activities are insufficient, increasing investors’ perceptions of fraud can reduce fraud-related losses. In this context, to the best of the authors’ knowledge, the present study might be among the first to investigate the impact of individuals’ perceptions of fraud on their investment intentions in crypto assets.