bluuebunny/crossref_metadata_2025 huggingface dataset:
United States federal indebtedness and fiscal policy trade‐offs
Authors: Gokhale Jagadeesh , Smetters Kent
Published: October 2024

Projected federal spending and taxes are distributed by birth year, gender, race, and lifetime education, using the Congressional Budget Office's 10‐year budget estimates and the Penn Wharton Budget Models' microsimulation. This enables measurement of conventional federal fiscal imbalance (FI): $162.6 trillion in present value, which is six‐fold larger than current debt held by the public. FI implies a shortfall of 26.1% in federal taxes, alternatively, an excess of 33.4% of federal expenditures. The equi‐proportional shortfall of expenditures plus taxes equals 14.6%. Excluding taxes and transfers of some groups, such as the elderly, increases the measured shortfall.
Improving Process‐Based Modelling to Simulate the Effects of Low‐Temperature Stress During Pre‐Anthesis on the Quality Characteristics of Wheat Grains
Authors: Ji Wenbin , Osman Raheel , Ma Jifeng , Jiang Xingtian , Wang Longqin , Xiao Liujun , Tang Liang , Cao Weixing , Zhu Yan , Liu Bing , Liu Leilei
Published: October 2024

Low temperatures in late spring pose a potential threat to the maintenance of grain yield and quality. Despite the importance of protein and starch in wheat quality, they are often overlooked in models addressing climate change effects. In this study, we conducted multiyear environment‐controlled phytotron experiments and observed adverse effects resulting from low‐temperature stress (LTS) on plant carbon and nitrogen dynamics, grain protein and starch formation, and sink capacity. We quantified the relationships between low temperature during the jointing and booting stages and plant nitrogen uptake, grain nitrogen accumulation, grain starch accumulation, grain setting, and potential grain weight using source–sink relationship‐based methods. The LTS factor was introduced to account for the cultivar‐specific to LTS at different growth stages. Compared with the original model, the improved model produced fewer errors when simulating aboveground nitrogen accumulation, grain protein concentration, grain starch concentration, grain starch yield, grain number, and grain weight under LTS, with reductions of 60%, 71%, 73%, 58%, 50% and 65%, respectively. The improvements in the model enhance its mechanism and applicability in assessing short‐term successive frost effects on wheat grain quality. Furthermore, when using the improved model, special attention should be given to the low‐temperature sensitivity parameters.
Root Circumnutation Reduces Mechanical Resistance to Soil Penetration
Authors: Leuther Frederic , Iseskog Daniel , Keller Thomas , Larsbo Mats , Pandey Bipin K. , Colombi Tino
Published: October 2024

Root circumnutation, the helical movement of growing root tips, is a widely observed behaviour of plants. However, our mechanistic understanding of the impacts of root circumnutation on root growth and soil exploration is limited. Here, we deployed a unique combination of penetrometer measurements, X‐ray computed tomography and time‐lapse imaging, and cavity expansion modelling to unveil the effects of root circumnutation on the mechanical resistance to soil penetration. To simulate differences in circumnutation amplitude and frequency occurring among plant species, genotypes and environmental conditions, we inserted cone penetrometers with varying bending stiffness into soil samples that were subjected to orbital movement at different velocities. We show that greater circumnutation intensity, determined by a greater circumnutation frequency in conjunction with a larger circumnutation amplitude, decreased the mechanical resistance to soil penetration. Cavity expansion theory and X‐ray computed tomography provided evidence that increased circumnutation intensity reduces friction at the cone‐soil interface, indicating a link between root circumnutation and the ability of plants to overcome mechanical constraints to root growth. We conclude that circumnutation is a key component of root foraging behaviour and propose that genotypic differences in circumnutation intensity can be leveraged to adapt crops to soils with greater mechanical resistance.
Coexpression Regulation of New and Ancient Genes in the Dynamic Transcriptome Landscape of Stem and Rhizome Development in “Bainianzhe”—An Ancient Chinese Sugarcane Variety Ratooned for Nearly 300 Years
Authors: Li Peiting , Yang Ruiting , Liu Jiarui , Huang Chaohua , Huang Guoqiang , Deng Zuhu , Zhao Xinwang , Xu Liangnian
Published: October 2024

The sucrose yield in sugarcane largely depends on stem morphology, including length, diameter and sugar content, making sugarcane stem a key trait in breeding. The “Bainianzhe” variety from Songxi County, Fujian Province, possesses both aerial stems and rhizomes, providing a unique model for studying stem development. We performed a spatiotemporal transcriptomic analysis of the base, middle and apical sections of both aerial stems and rhizomes. The analysis categorized transcriptomes by developmental stage—base, middle and apical—rather than environmental differences. Apical segments were enriched with genes related to cell proliferation, while base segments were linked to senescence and fibrosis. Gene regulatory networks revealed key TFs involved in stem development. Orphan genes may be involved in rhizome development through coexpression networks. Plant hormones, especially genes involved in ABA and GAs synthesis, were highly expressed in rhizomes. Thiamine‐related genes were also more prevalent in rhizomes. Furthermore, the apical segments of rhizomes enriched in photosynthesis‐related genes suggest adaptations to light exposure. Low average temperatures in Songxi have led to unique cold acclimation in Bainianzhe, with rhizomes showing higher expression of genes linked to unsaturated fatty acid synthesis and cold‐responsive calcium signalling. This indicates that rhizomes may have enhanced cold tolerance, aiding in the plant's overwintering success.
Dialetheism and the countermodel problem
Authors: Fjellstad Andreas , Martin Ben
Published: October 2024

According to some dialetheists, we ought to reject the distinction between object and meta‐languages. Given that dialetheists advocate truth‐value gluts within their object‐language, whether in order to solve the liar paradox or for some other reason, this rejection of the object‐/meta‐language distinction comes with the commitment to use a glutty metatheory. While it has been pointed out that a glutty metatheory brings with it expressive deficiencies, we highlight here another complication arising from the use of a glutty metatheory, this time evidential in nature. According to this countermodel problem, while the thoroughgoing dialetheist who embraces a glutty metatheory can justify their acceptance of a rule of inference's invalidity using countermodels, to justify their renunciation of an unwanted rule they actually require the means to warrant their rejection of the rule's validity—which cannot be supplied by countermodels based on a standard dialetheic semantics. We end by sketching out a possible solution for the thoroughgoing dialetheist using a bilaterialist semantics.
SMARCB1‐deficient malignant neoplasm of the pancreas with heterogeneous morphologies that cannot be classified into existing histologic types
Authors: Kouchi Yusuke , Sakai Nozomu , Harada‐Kagitani Sakurako , Eto Ryotaro , Mishima Takashi , Takano Shigetsugu , Nasu Katsuhiro , Ikeda Jun‐ichiro , Ohtsuka Masayuki , Kishimoto Takashi
Published: October 2024

A 50‐year‐old male with a pancreatic tail tumor underwent distal pancreatectomy. At 14 and 27 months after the primary surgery, metachronous liver metastases were identified and partial hepatectomies were performed for each. Pathologic findings of the primary pancreatic tumor were heterogeneous, but they essentially categorized into two components based on their cytologic features: (i) clear cell component and (ii) epithelioid cell component. The metastatic hepatic tumor was entirely composed of the epithelioid cell component. SMARCB1 expression was lost by immunohistochemistry and heterozygous deletion of SMARCB1 was identified by fluorescence in situ hybridization for both the primary and metastatic tumors. Targeted DNA sequencing of a metastatic hepatic tumor sample was performed and SMARCB1 loss was identified. Based on the morphologic, immunohistochemical, and molecular analyzes, the present case was difficult to classify into any of the existing entities. SMARCB1 deficiency might play a key role in the tumorigenesis.
Changes in social relationships from 26 to 34 years of age in adults born very preterm
Authors: Gonen Elif , Twilhaar E Sabrina , Baumann Nicole , Busch Barbara , Bartmann Peter , Wolke Dieter
Published: October 2024

Background

Very preterm and/or very low birthweight (VP/VLBW; <32 weeks' gestation and/or <1500 g birthweight) individuals rated their partner and peer relationships lower than term‐born individuals in emerging adulthood, but their quality of relationships with parents has been rarely investigated. Moreover, it is unclear whether previously reported differences in social relationship characteristics persist or lessen from emerging to established adulthood.

Objectives

To investigate changes in social relationship characteristics in VP/VLBW adults compared to term‐born adults from 26 to 34 years and whether the association between VP/VLBW and social relationship characteristics varies according to sex.

Methods

In this prospective whole‐population birth cohort study in South Bavaria, Germany, social relationship characteristics with parents, partners and peers, and overall social relationships across these domains were evaluated with a Life Course Interview at 26 and 34 years. Interview items related to these domains were extracted and scored as 0 (optimal) and 1 (non‐optimal). Each score was summed into domain‐specific composite scores and standardised according to the total sample.

Results

Participants included 262 VP/VLBW (52.7% males) and 230 term‐born individuals (47.0% males). VP/VLBW adults had lower overall social relationship scores than term‐born adults (β = −.61, 95% CI −0.85, −0.37). Specifically, partner (β = −.50, 95% CI−0.74, −0.27) and peer relationship scores (β = −.55, 95% CI−0.78, −0.32) were lower than those of term‐born adults, but scores did not differ for parent relationships. On average, partner (β = .25, 95% CI 0.14, 0.35) and peer relationship scores increased (β = .16, 95% CI 0.03, 0.29), while parent relationship scores decreased (β = −.64, 95% CI−0.79, −0.49) from 26 to 34 years. These changes were similar for VP/VLBW and term‐born individuals.

Conclusions

Patterns of change for the improved partner and peer but worsening parental social relationship scores were common across VP/VLBW and term‐born adults, but differences between the two groups persisted from 26 to 34 years.
Damping Optimization in Locally Resonant Metastructures via Hybrid GA-PSO Algorithms and Modal Analysis
Authors: Alimohammadi Hossein , Vassiljeva Kristina , HosseinNia S. Hassan , Ellervee Peeter , Petlenkov Eduard
Published: October 2024

This study explores the optimization of bandgap characteristics in locally resonant metastructures through advanced artificial intelligence (AI) and optimization algorithms, focusing on the accurate estimation of resonator damping ratios. By developing a novel mathematical framework for metastructure analysis, this research diverges from traditional methods, offering a more nuanced approach to bandgap manipulation. This research significantly improves metastructure modeling accuracy by precisely estimating resonator and structural damping ratios, enhancing model fidelity crucial for analysis, control strategies, and design optimization. Through a combination of model simulations and experimental validation, the efficacy of the Hybrid Genetic Algorithm-Particle Swarm Optimization (GA-PSO) algorithm is demonstrated, highlighting its potential for practical applications in engineering metastructures. This paper not only provides a robust method for estimating damping ratios but also opens new avenues for future research, including the application of machine learning techniques and the development of intelligent materials. The findings of this study contribute to the foundational understanding necessary for the advancement of mathematical modeling metamaterials, with broad implications for industries where precise vibration control is crucial.
Design Optimization of Mechanism-Free Ornithopters Based on a Coupled State-Space Model
Authors: Shan Xin , Katibeh Mohammad , Bilgen Onur
Published: October 2024

A so-called solid-state (i.e., mechanism-free) ornithopter can be achieved by utilizing induced-strain actuators such as piezoelectric material-based devices — specifically piezocomposite devices. Such ornithopters with induced-strain actuated wings eliminate the need for electromagnetic motors and conventional power transmission mechanisms, potentially saving weight and energy consumption, improving reliability and flexibility, and reducing overall mechanical complexity. Given the complexity of such system, featuring a high number of design variables and nonlinearities, achieving an optimized configuration is crucial.

In their previous research, the authors developed a novel model to account for dynamic two-way coupling and nonlinearities using a state space representation for mechanism-free ornithopters. The model considered (1) two-way fluid-structure interaction, (2) body-wing coupling, and (3) wing bend-twist coupling. Based on the state space representation of the ornithopter, the current paper focuses on a design optimization framework utilizing a multi-objective genetic algorithm. The design variables considered include ornithopter body inertia, piezocomposite device positions and orientations, excitation voltage, frequency, etc. The optimization algorithm is initially validated for convergence using established test functions. Subsequently, the optimization procedure is carried out for multiple case studies with a variation of fitness metrics that represent the aerodynamic and structural performance of the ornithopter. The selected objective functions encompass structural metrics such as wing weight and compliance, as well as aerodynamic metrics such as lift and thrust force amplitudes.
Impact of Fabrication Process Variations on Epoxy Shape Memory Polymer Mechanical Properties Across Temperature Gradients
Authors: Vallejo Ciro Maria Isabel , Carvajal Loaiza Manuel Jose , Pankey Gage , Restrepo Vanessa
Published: October 2024

Shape Memory Polymers (SMPs) are versatile polymeric materials that are able to undergo reversible shape changes triggered by external stimuli like temperature, electric current, UV light, and magnetic fields. Epoxy Shape Memory Polymers (ESMPs), a subset of SMPs, are notably influenced by compositional changes. While previous studies focused on the response of thermal and mechanical properties based on composition changes, understanding how the fabrication process affects mechanical performance remains limited. This research addresses the mentioned gap, by systematically evaluating the mechanical properties at different temperatures, and particularly considering variations in time and temperature during the curing process of the ESMP. Using the Taguchi method, an L9 orthogonal array design was employed with a signal-to-noise quality characteristic analysis. Ninety ESMP samples with consistent composition but varying curing and post-curing parameters were produced. ESMP molar ratio was chosen for a glass transition temperature of 36°C, enabling sample programming by body temperature. Tensile testing at different environmental conditions revealed significant impacts of fabrication process on the ESMP mechanical behavior. Longer curing and post-curing times and higher temperatures increased stiffness and strength, while shorter processing times at lower temperatures decreased these properties. Maintaining the manufacturing parameters and testing the samples at higher temperature reduced the stiffness, strength, and strain at failure. These findings facilitate customized fabrication for applications requiring variable properties, particularly in active mechanical interfaces responding to external stimuli.
Neural Network-Based Sensorless Control of a Shape Memory Alloy Actuator
Authors: Koshiya Krunal Jagdishbhai , Rizzello Gianluca , Motzki Paul
Published: October 2024

Shape memory alloy (SMA) wires can be used as actuators when heated above their austenite finish temperature, as their length reduces because of a phase transformation from martensite to austenite. During phase transformation, changes in electrical properties such as the wire resistance can be correlated to changes in wire length, thus enabling the self-sensing operation mode. This effect can be used to implement sensorless closed-loop control, where the mechanical feedback is provided by a position estimation obtained through the wire resistance. Self-sensing-based control has a significant advantage over sensor-based control, as it removes the need of additional electro-mechanical transducers into the control system. Due to strong nonlinearities intrinsic to SMA behavior, the relationship between resistance and wire elongation is often complex and hysteretic, making the practical implementation of self-sensing architectures in SMA rather challenging.

In this paper, we present a self-sensing-based control of an SMA wire actuator in which a neural network is used to estimate the displacement by using electrical properties. The estimated displacement is further used as feedback to a PI control system, allowing in turn to implement sensorless closed-loop control on an experimental prototype. The performance of the self-sensing-based PI control is compared to laser sensor based PI control, in which position feedback is provided by a laser sensor.
The Physics of Bio-Inspired Covert Flaps As Flight Control Devices
Authors: Zekry Diaa A. , Wissa Aimy A.
Published: October 2024

Covert-inspired flaps are novel feather-inspired aerodynamic control surfaces that enable stability augmentation and maneuvering in small-scale Uncrewed Aerial Vehicles (sUAVs), especially for tailless configurations. For the first time, this paper uses time-averaged particle image velocity (PIV) to reveal the effect of static covert-inspired flaps on the flow field when simultaneously deflected on a wing’s upper (suction) and lower (pressure) surfaces. Compared to a flap deployed on a single side, the simultaneously deflected flaps enhance the modulation range of the aerodynamic response (i.e., lift, drag, and pitching moment), making them more effective as control surfaces. Results reveal two categories explaining why the modulation range of the simultaneous deflection response is larger than each side deflection alone. Limit-bounded cases, where the response is within the bounds of the single-sided experiments, and limit-expanding cases, where the interaction between the suction and pressure sides flaps is crucial. Limit-expanding cases are associated with flow fields with increased wake size or flow features that cannot be reconstructed from the suction-only or pressure-only flow fields. Using the velocity fields, we also show that superposition better predicts post-stall responses than pre-stall responses because the flow features present in the wake of the post-stall flow are similar between suction-only, pressure-only, and simultaneous deflection experiments. Finally, we show that the post-stall flow is more sensitive to pressure side flaps than suction side flaps due to significant flow changes occurring at the pressure side when the pressure side flap is deflected, which can increase the size of the wake and significantly alter the response. The results from the flow fields support the data-driven aerodynamic models that express the lift, drag, and pitching moment as a function of the flow and flap parameters.
Systematic Design of Adaptive Connectors Based on Shape Memory Alloys for Electrical Vehicles
Authors: Hofer Andreas , Pagel Kenny , Langbein Sven , Lembke Dietrich , Lehmann Dirk , Drossel Welf-Guntram
Published: October 2024

Fast charging of electric vehicles (EVs) plays a critical role in the adoption of EVs and thereby in the transition from fossil fuels to renewable energy sources in the transportation sector. However, there are significant limitations to the maximum electrical power that can be transferred during the charging process. One of the biggest challenges is the high electrical contact resistance (ECR) between the charging plug and the vehicle inlet, which leads to significant waste heat generation and associated energy loss. These factors not only affect the efficiency of the charging process, but also carry the risk of damage to the connector system and the EV.

In response to these challenges, this paper proposes a novel approach for an adaptive connector based on thermal shape memory alloys (SMAs). The proposed adaptive connector is designed to increase contact forces only during the charging process, effectively mitigating ECR while ensuring compatibility with existing charging infrastructure. As a result, this technology promises to unlock higher transmission power capabilities and significantly reduce charging times. An integral aspect of this proposed solution is the inherent ability of SMA-based connectors to self-activate in response to the initial high ECR, generating joule heating that triggers the SMA actuator. This eliminates the need for additional power or active actuator control, allowing for a streamlined and energy efficient charging process.

This paper outlines a systematic design framework for the implementation of adaptive connectors, including comprehensive integration of SMA actuators and meticulous optimization strategies tailored to ensure efficient and reliable fast charging of EVs. Evaluation and validation of the system’s effectiveness is underway through trials using combined charging systems (CCS) Type 2 connectors tailored for High Power Charging (HPC) applications, which can accommodate charging powers of up to 500kW. Through these concerted efforts, this research aims to drive the evolution of fast charging technology, catalyzing the widespread adoption of electric vehicles and accelerating the transition to sustainable transportation solutions.
Energy-Efficient Multi Smart Materials Based Actuator Demonstrator Combining Shape Memory Alloy Wires With Electrostatic Clutches
Authors: Venkatachalam Vignesh , Gorges Tom , Bruch Daniel , Nalbach Sophie , Rizzello Gianluca , Motzki Paul
Published: October 2024

This paper presents an actuator demonstrator showcasing a combination of shape memory alloy (SMA) wires and electrostatic (ES) clutches in a multi smart materials based actuator system. Shape memory alloy actuators demonstrate high energy densities and can transmit large actuation forces. However, they suffer from low energy efficiency due to the fact that they are thermal actuators. This drawback inhibits the adoption of SMA actuators in position-holding applications, for example, grasping objects using a robot hand. ES clutches can overcome this drawback of SMA actuators due to their high energy efficiency and ability to withstand high frictional shear stresses. A combination of the two actuator systems combining large actuation forces provided by SMA actuators with the energy-efficient actuation of ES clutches can be used in applications requiring the holding of a desired position or configuration. A demonstrator showcasing a combination of SMA wires with ES clutches demonstrating two different actuation modes: a linear actuator module and an SMA wire-actuated continuum robot is presented here. This demonstrator aims to showcase the versatility of this multi smart materials based actuator system in different actuation scenarios thereby opening further research avenues for smart materials based hybrid actuator systems for energy-efficient actuation.
Production and Validation of Non-Planar Electroplated 3D Printed Circuit Boards
Authors: Simonson Kevin , Valdes Alexander , Narvaez Diana , Newell Brittany
Published: October 2024

Multi-material 3D Printing is an emerging technology that allows users to create more complex and more functional products using multiple filament options. Many methods and systems are currently used to accomplish a multi-material print and the machines capable of this process have improved significantly in recent years. Electroplating is a process that allows for thin layers of metal to be deposited onto conductive substrates. It is achieved through an electrical-chemical reaction where an anode of a sacrificial material is charged alongside a cathode of the desired object to be plated while they are both submerged in an electrolytic solution. Passing a current through the solution for an extended period of time allows for ions of the sacrificial anode to attach to the cathode and form a uniform layer. Combining these two manufacturing processes allows for the creation of non-planar, electrically conductive traces, or Printed Circuit Boards (PCBs). For this work samples were printed on a Lulzbot Pro Dual Extruder model with a traditional Polylactic Acid (PLA) filament and an electrically conductive PLA filament in an orientation that allowed smooth, continuous traces to be manufactured. The specimens were then submerged as the cathode in a copper-sulfate electroplating solution alongside a specified amount of copper proportionate to the surface area that was coated for a set duration to produce a copper layer on the traces. A frequency response analysis (FRA) was performed with the electroplated sample. Using this FRA data, the resonant frequency was quantified to show where and how strongly the frequency-based impedance affects the circuit’s performance. In conjunction with FRA, a Wheatstone Bridge was constructed in accordance with IEEE Std118-1978 to measure the resistance of the trace to characterize the resistivity of the material. These values were compared with results from standard copper. using statistical methods.
Modelling of Dielectric Elastomer Multiactuator Networks As Cooperative Systems
Authors: Jiao Chen , Tripathi Ashwani Sharan , Marschner Uwe , Richter Andreas , Henke Ernst-Friedrich Markus
Published: October 2024

Collaborative multi-actuator systems represent a promising avenue for the development of visionary applications such as robotics, medical appliances, and advanced user interfaces. Among various technologies, Dielectric Elastomer (DE) transducers exhibit synergistic properties conducive to cooperative systems. The same material can fulfill different tasks, such as actuation, sensing, or energy harvesting. Combining multiple DE actuators and DE switches can enable similar soft structures to implement basic logic and storage functions. In this paper, we present a mathematical model for a DE transducer network capable of complex actuation tasks. Drawing from our research on DE sensors and actuators, we have developed a model that integrates DE components to simulate multi-actuator networks. Multiple DE switches are interconnected through logic unit designs to achieve complex electro-mechanical behaviors. We predict the multiple outputs of a single input pulse voltage for a highly integrated inverter system through simulation. It opens more possibilities in the application field of cooperative multi-actuator systems.
Ambient pressure x-ray photoelectron spectroscopy study on the initial atomic layer deposition process of platinum
Authors: Kokkonen E. , Nieminen H.-E. , Rehman F. , Miikkulainen V. , Putkonen M. , Ritala M. , Huotari S. , Schnadt J. , Urpelainen S.
Published: October 2024

The initial adsorption of MeCpPtMe3 is investigated using synchrotron-based ambient pressure x-ray photoelectron spectroscopy (XPS). The experiments are done on a native oxide-covered Si substrate. In addition, a reaction with O2 and the created Pt surface was investigated. Inspiration for the reaction studies was found from atomic layer deposition of metallic Pt, process that uses the same compounds as precursors. With time-resolved XPS, we have been able to observe details of the deposition process and especially see chemical changes on the Pt atoms during the initial deposition of the Pt precursor. The change of the binding energy of the Pt 4f core level appears to occur on a different timescale than the growth of the active surface sites. The very long pulse of the Pt precursor resulted in a metallic surface already from the beginning, which suggest chemical vapor deposition-like reactions occurring between the surface and the precursor molecules in this experiment. Additionally, based on the XPS data measured after the Pt precursor pulse, we can make suggestions for the reaction pathway, which point toward a scenario that leaves carbon from the MeCpPtMe3 precursor on the surface. These carbon species are then efficiently removed by the subsequent coreactant pulse, leaving behind a mostly metallic Pt film.
Impact of monolayer WS2 surface properties on the gate dielectrics formation by atomic layer deposition
Authors: Lin Zaoyang , Dekelver Sven , Cott Daire , Groven Benjamin , Sergeant Stefanie , Conard Thierry , Wu Xiangyu , Morin Pierre , Lin Dennis , Lockhart de la Rosa Cesar Javier , Kar Gouri Sankar , Delabie Annelies
Published: October 2024

Two-dimensional transition metal dichalcogenides (2D TMDs), such as MoS2 and WS2, have emerged as promising channel materials for future generation transistors. However, carbon-based surface contaminants pose a significant challenge in the formation of high-quality metal–oxide–semiconductor gate stacks for 2D TMDs. Carbon-based surface contaminants are known to be present even on directly grown 2D TMDs that have not been in contact with polymers. These organic contaminants affect precursor adsorption during atomic layer deposition (ALD) of gate dielectrics on 2D TMDs and as such the 2D-dielectric interface. This study examines the effectiveness of predeposition annealing in mitigating carbon-based contaminants while maintaining the integrity of a directly grown WS2 monolayer on a SiO2 substrate. We show that a WS2 monolayer on a SiO2/Si substrate remains stable during vacuum annealing at temperatures up to 400 °C. Water contact angle measurements and x-ray photoelectron spectroscopy confirm that the surface concentration of carbon starts to decrease at 150 °C. Thermal anneal improves the surface coverage of Al2O3 for both conventional chemisorption-based ALD and physisorbed-precursor-assisted ALD processes by facilitating more effective Al2O3 nucleation on the WS2 monolayer. The impact of predeposition anneal on the Al2O3 growth behavior in both processes can be explained by changes in surface contaminant levels. Our results underscore the importance of surface pretreatment in dielectric deposition on 2D TMDs and demonstrate that predeposition anneal is an effective method to enhance ALD-based dielectric deposition on directly grown 2D TMDs.
Expanded geographic distribution for two
Legionella pneumophila
sequence types of clinical concern
Authors: Hamlin Jennafer A. P. , Kozak-Muiznieks Natalia A. , Mercante Jeffrey W. , Rishishwar Lavanya , Norris Emily T. , Gaines Anna B. , Ishaq Maliha K. , Winchell Jonas M. , Willby Melisa J.
Published: October 2024

Legionella pneumophila
serogroup 1 sequence types (ST) 213 and 222, a single-locus variant of ST213, were first detected in the early 1990s in the Midwest United States (U.S.) and the late 1990s in the Northeast U.S. and Canada. Since 1992, these STs have increasingly been implicated in community-acquired sporadic and outbreak-associated Legionnaires’ disease (LD) cases. We were interested in understanding the change in LD frequency due to these STs and identifying genetic features that differentiate these STs from one another. For the geographic area examined here (Mountain West to Northeast) and over the study period (1992–2020), ST213/222-associated LD cases identified by the Centers for Disease Control and Prevention increased by 0.15 cases per year, with ST213/222-associated LD cases concentrated in four states: Michigan (26%), New York (18%), Minnesota (16%), and Ohio (10%). Additionally, between 2002 and 2021, ST222 caused at least five LD outbreaks in the U.S.; no known outbreaks due to ST213 occurred in the U.S. during this time. We compared the genomes of 230 ST213/222 isolates and found that the mean of the average nucleotide identity (ANI) within each ST was high (99.92% for ST222 and 99.92% for ST213), with a minimum between ST ANI of 99.50% and a maximum of 99.87%, indicating low genetic diversity within and between these STs. While genomic features were identified (e.g., plasmids and CRISPR-Cas systems), no association explained the increasing geographic distribution and prevalence of ST213 and ST222. Yet, we provide evidence of the expanded geographical distribution of ST213 and ST222 in the U.S.

IMPORTANCE

Since the 1990s, cases of Legionnaires’ disease (LD) attributed to a pair of closely related
Legionella pneumophila
variants, ST213 and ST222, have increased in the U.S. Furthermore, between 2002 and 2021, ST222 caused at least five outbreaks of LD in the U.S., while ST213 has not been linked to any U.S. outbreak. We wanted to understand how the rate of LD cases attributed to these variants has changed over time and compare the genetic features of the two variants. Between 1992 and 2020, we determined an increase of 0.15 LD cases ascribed to ST213/222 per year in the geographic region studied. Our research shows that these STs are spreading within the U.S., yet most of the cases occurred in four states: Michigan, New York, Minnesota, and Ohio. Additionally, we found little genetic diversity within and between these STs nor could specific genetic features explain their geographic spread.
Rapid and sensitive detection of
Mycobacterium tuberculosis
using nested multi-enzyme isothermal rapid amplification in a single reaction
Authors: Chang Yingchao , Zhang Mi , Liu Gaowen , Wu Xinlin , Yan Qiaolu , Yang Cuixian , Liu Li , Feng Yue , Xia Xueshan
Published: October 2024

Tuberculosis (TB) remains a major global health problem, and there is an urgent need for rapid, sensitive, and easy-to-use diagnostic technologies to improve TB diagnosis. In this study, we developed the nested multi-enzyme isothermal rapid amplification (nestMIRA) assay for TB. We designed several pairs of primers and probes targeting the IS6110 sequence of
Mycobacterium tuberculosis
(Mtb) and performed combinatorial testing to optimize the performance of the TB nestMIRA assay. The reaction can be performed at a constant temperature of approximately 40°C and completed within 30 minutes in the same tube without opening the central cap. There has been no cross-reactivity with common
non-tuberculous mycobacteria
(NTB) and respiratory pathogens. The TB nestMIRA assay has a minimum detection limit of 5 copies/μL for H37Rv genomic DNA and a limit of quantification of 100 CFU/ml. To test the diagnostic performance of the TB nestMIRA assay, we conducted a 163-person clinical cohort study using comprehensive reference standards as the gold standard for clinical diagnosis. Our study showed that TB nestMIRA performed slightly better than GeneXpert MTB/RIF (Xpert) (85.27% vs. 82.17%) and significantly better than culture (55.81%) and acid-fast bacillus (AFB) smear (38.76%). The TB nestMIRA assay offers speed, specificity, sensitivity, and convenience. We believe that it has the potential to be a rapid alternative for TB diagnosis, particularly in resource-limited settings.

IMPORTANCE

In this study, we have successfully developed a method called nested multi-enzyme isothermal rapid amplification (nestMIRA) for the detection of
Mycobacterium tuberculosis
(Mtb). This method involves a two-step thermostatic amplification process in the same tube and can be read using fluorescence and lateral flow dipstick (LFD) assays. It is known to be rapid, specific, and highly sensitive. Our method has shown promising results in the detection of clinical specimens, and we believe that it can be a valuable tool for the rapid detection of Mtb in a clinical setting.
Device-measured vigorous intermittent lifestyle physical activity (VILPA) and major adverse cardiovascular events: evidence of sex differences
Authors: Stamatakis Emmanuel , Ahmadi Matthew , Biswas Raaj Kishore , del Pozo Cruz Borja , Thøgersen-Ntoumani Cecilie , Murphy Marie H , Sabag Angelo , Lear Scott , Chow Clara , Gill Jason M R , Hamer Mark
Published: October 2024

Background

Vigorous intermittent lifestyle physical activity (VILPA) refers to brief bouts of intense physical activity embedded into daily life.

Objective

To examine sex differences in the dose–response association of VILPA with major adverse cardiovascular events (MACE) and its subtypes.

Methods

Using multivariable-adjusted cubic splines, we examined the associations of daily VILPA duration with overall MACE and its subtypes (incident myocardial infarction, heart failure and stroke) among non-exercisers (individuals self-reporting no leisure-time exercise and no more than one recreational walk per week) in the UK Biobank. We also undertook analogous analyses for vigorous physical activity among exercisers (individuals self-reporting participation in leisure-time exercise and/or recreational walking more than once a week).

Results

Among 13 018 women and 9350 men, there were 331 and 488 all MACE, respectively, over a 7.9-year follow-up. In women, daily VILPA duration exhibited a near-linear dose–response association with all MACE, myocardial infarction and heart failure. In men, dose-reponse curves were less clear with less evidence of statistical signifigance. Compared with women with no VILPA, women’s median daily VILPA duration of 3.4 min was associated with hazard ratios (HRs; 95% confidence intervals) of 0.55 (0.41 to 0.75) for all MACE and 0.33 (0.18 to 0.59) for heart failure. Women’s minimum doses of 1.2–1.6 min of VILPA per day were associated with HRs of 0.70 (0.58 to 0.86) for all MACE, 0.67 (0.50 to 0.91) for myocardial infarction, and 0.60 (0.45 to 0.81) for heart failure. The equivalent analyses in UK Biobank’s accelerometry sub-study exercisers suggested no appreciable sex differences in dose–response.

Conclusions

Among non-exercising women, small amounts of VILPA were associated with a substantially lower risk of all MACE, myocardial infarction and heart failure. VILPA may be a promising physical activity target for cardiovascular disease prevention, particularly in women unable or not willing to engage in formal exercise.
Low physical fitness indicates future injury, mental health, menstrual cycle disruptions, and burnout in female emergency service personnel and healthcare providers
Authors: Edwards Chris M. , Puranda Jessica L. , Miller Émilie , MacDonald Meaghan L. , Aboudlal Mohamed , Adamo Kristi B.
Published: October 2024

Musculoskeletal injury (MSKi), depression, anxiety, and burnout place a considerable burden on emergency services personnel and healthcare providers (HCP). Physical fitness is related to both mental and physical health in these populations, but females in these are hugely underrepresented in this literature. As female representation in first-responder and HCP roles increases, the need for female-specific research is needed. This study examines physical fitness as a short-term indicator of future reproductive health, MSKi, and mental health for females employed as first-responders or HCP. Thirteen first-responders and 29 HCP completed an initial health and demographics questionnaire, a comprehensive physical assessment (e.g., bone mineral density, muscular strength, muscular endurance, muscular power, flexibility, and aerobic capacity), and a health questionnaire 6–7 months after the physical testing. We found that (i) bone mineral density, relative upper body strength, and lower body power were related to sustaining future MSKi, (ii) better lower body endurance and flexibility were related to future menstrual cycle disruptions, and (iii) low bone mineral density was related to future self-reported burnout and Patient Health Questionnaire score ≥ 10. Physical fitness characteristics can be helpful indicators of future MSKi risk, menstrual cycle disruptions, and mental health status in females employed in arduous occupations.
Non-parametric reconstruction of the fine structure constant with galaxy clusters
Authors: Ferreira Marcelo , Holanda Rodrigo F. L. , Gonzalez Javier E. , Colaço L. R. , Nunes Rafael C.
Published: October 2024

Testing possible variations in fundamental constants of nature is a crucial endeavor in observational cosmology. This paper investigates potential cosmological variations in the fine structure constant ($$\alpha $$
α
) through a non-parametric approach, using galaxy cluster observations as the primary cosmological probe. We employ two methodologies based on galaxy cluster gas mass fraction measurements derived from X-ray and Sunyaev–Zeldovich observations, along with luminosity distances from type Ia supernovae. We also explore how different values of the Hubble constant ($$H_0$$

H
0

) impact the variation of $$\alpha $$
α
across cosmic history. When using the Planck satellite’s $$H_0$$

H
0

observations, a constant $$\alpha $$
α
is ruled out at approximately the 3$$\sigma $$
σ
confidence level for $$z \lesssim 0.5$$

z
≲
0.5

. Conversely, employing local estimates of $$H_0$$

H
0

restores agreement with a constant $$\alpha $$
α
.
Singularities of worldsheets along framed particle trajectories in Minkowski three-space
Authors: Zhang Zihan , Fan Xiaoming , Wang Zhigang
Published: October 2024

Modeling the worldsheets along the trajectory (a string) of a point particle (a 0-brane) as two timelike surfaces in 3-subspace of Minkowskian spacetime, respectively, the work aims at analyzing the topological structures of these two worldsheets along the trajectory of the point particle from the view point of singularity theory. Different from the regular curves, the traveling trajectory (modeled as framed timelike curve) of the particle is allowed to be singular, two worldsheets are generated by the traveling trajectories of the particle. As applications of singularity theory, we classify the singularities of these two worldsheets along the traveling trajectory of the particle. Using the approach of the unfolding theory in singularity theory, we find two new geometric invariants which are useful for characterizing the local topological structures of singularities of these two worldsheets along the particle. It is revealed that there exist cuspidal edge type and swallowtail type of singularities for these two worldsheets under the appropriate conditions of geometric invariants. Meanwhile, it is also pointed out that the types of singularities of these two worldsheets have a close relationships to the order of contacts between these two worldsheets and two timelike planes, respectively. Finally, some examples are presented to interpret our theoretical results.
Dynamics of a Discrete Population Model
Authors: Li Mingshan , Xie Naiming , Shi Lei , Huang Xiaojun
Published: October 2024

In order to explore the influences of the strong Allee effect on population evolution in two-patch environments, this paper constructs a population model with discrete diffusion and analyzes its dynamics. Using the center manifold theorem, we discuss the codimension-one bifurcation, such as flip bifurcation, of the model. The qualitative structures and stability of the model at the degenerate fixed point are obtained from the approximation of flow. Based on the theoretical analysis results, we investigate the influences of the strong Allee effect and diffusion on population evolution. The qualitative structures of degenerate fixed point and numerical simulation show that the strong Allee effect will make the population tend to a stable size when the two initial population patch sizes are equal and exceed a threshold. But the stable size of population does not exceed the carrying capacity, depending on the constant Allee effect and carrying capacity, which differ from the conclusion of logistic model that population size tends to the carrying capacity. However, if the two initial population patches are equal in size and below this threshold, or if the sizes of the initial population patches are unequal, the population size will decrease. The fixed point becomes degenerate with respect to the strong Allee effect causing the population tend to a stable size below carrying capacity, which exacerbates the complexity of population evolution.
Polarimetric thermoacoustic imaging
Authors: Long Jiawei , Liang Zheng , Tu Yihang , Xie Shimeng , Huang Lin , Li En
Published: October 2024

Thermoacoustic imaging (TAI) contrast comes from different electrical properties (EPs) of microwave absorption. However, the relationship between the permittivity distribution and the electric field polarization limits the application of TAI in some extent. Here, we present a polarimetric thermoacoustic imaging (pTAI) system based on a rotary waveguide. By optimizing a rotary waveguide (insertion loss < 0.2[Formula: see text]dB, return loss > 15[Formula: see text]dB at 3[Formula: see text]GHz), the excitation wave emitted from a horn antenna can rotate freely in the direction of polarization. The multi-polarization pulsed microwave signal is used to evoke the thermoacoustic signals (TAS) of samples in different polarimetric directions. The simulation for pTAI with a multi-directional sample is first obtained. Then, we rotated the rotary waveguide at 10∘/s and experimentally demonstrated the performance of pTAI by imaging three randomly placed soy sauce tubes and ex vivo beef. This study suggests that pTAI has potential for dielectric properties “diffusion” mapping, for example, provides conductivity tensor mapping of brain and muscle.
HOW DOES TRADE IN DIGITALLY DELIVERED SERVICES AFFECT EMPLOYMENT IN AFRICA?
Authors: RAKOTONDRAZAKA TOJO HERILANTO , XU LINGLI
Published: October 2024

The rapid advancement of technology and the increasing accessibility of the Internet are driving changes in various economic activities, including international trade. This study explores the relationship between digital trade and employment across 30 African countries from 2009 to 2020, with a particular focus on the role of digitally delivered services as a proxy for digital trade. Utilizing panel data and employing PCSE and IV-2SLS estimation techniques, the findings reveal that while the expansion of digitally delivered services may contribute to a reduction in formal employment, it also fosters growth in the industrial and services sectors, while exerting downward pressure on employment in agriculture. These results are robust and highlight the sector-specific dynamics of digital trade’s impact on labor markets.