bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating the CTDIvol with helical acquisitions: Results from a national generalizability study
Authors: Barreto Izabella L. , Gress Dustin A. , Leon Stephanie M. , Schwarz Bryan C. , Kobistek Robert J. , Mahesh M. , Tomlinson James A. , Dillon Chad M. 
Published: December 2024

AbstractBackgroundWhile many clinical computed tomography (CT) protocols use helical scanning, the traditional method for measuring the volume CT Dose Index (CTDIvol) requires modifying the helical protocol to perform a single axial rotation. This modification can present challenges and mismatched settings across various scanner models.PurposeThis study investigates the generalizability of a helical methodology for estimating CTDIvol across a diverse range of participants, CT scanner models, and protocol parameters.MethodsA web‐based platform collected axial and helical CTDIvol measurements from 24 medical physicists who submitted 569 data sets obtained using four CT protocols on scanners from seven CT manufacturers. Various parameters were tested for tube voltage (70–140 kVp), rotation time (0.25–1.50 s), beam width (8–80 mm), and pitch (0.29–3.0) settings. Measurements from the two methodologies were assessed for reproducibility using three repeated exposures and then compared to each other and to the scanner‐displayed CTDIvol. Agreement between the methodologies was assessed using Bland–Altman analysis, linear regression, paired t‐tests, and a paired two one‐sided tests (TOST) procedure with equivalence margins of 5% of the mean protocol CTDIvol. The impact of beam width and pitch on measurement accuracy was assessed using linear regression analysis and an independent t‐test.ResultsThis study demonstrated better measurement reproducibility with the helical method (p < 0.05) and excellent concordance between helical and axial measurements (CCC > 0.99), with an average difference of ‐0.61 mGy (limits of agreement: ‐4.54 and 3.32). The TOST analysis confirmed that the measurement methods were statistically equivalent within the defined equivalence margins. The number of measurements that differed from the displayed CTDIvol by more than ± 20% was 10 for the axial method and 22 for the helical method. We did not identify a linear correlation between measurement accuracy and beam width or pitch (R2 < 0.06). However, differences between axial and helical methods were significant for protocols with beam widths up to 40 mm versus those greater than 40 mm, as well as for protocols with pitch factors up to 1.0 compared to those greater than 1.0 (p < 0.001).ConclusionUtilizing the same equipment currently used for measuring CTDIvol and a simple measurement setup, the helical method offers an alternative measurement methodology that can be seamlessly implemented by medical physicists and adopted by regulatory and accrediting bodies for routine quality control of CT scanners.
On the Observation of Glucose–Insulin Models
Authors: Röbenack Klaus , Gerbet Daniel 
Published: December 2024

AbstractThe glucose–insulin subsystem has been modeled in different ways as a low‐dimensional dynamical system. These models consist of various parameters, which are fitted such that the model coincides with specific experiments. For individuals with the Diabetes Mellitus syndrome model‐based controllers for insulin injection have been proposed. These controllers, however, require the knowledge of the model parameters as well as the full systems state, which must be estimated as well. In addition, the system is disturbed by, in general, unknown carbohydrate intake. From a control‐theoretic point of view, the state estimation using only the measurable glucose concentration is an observer problem. Due to the nonlinearity of the system, its observability is more difficult to test. There may also be some points in the state space, where the system is not locally observable for some parameters tuples. Those issues are important for a robust observer design. In this contribution, several observers are discussed for the widely used Bergman minimal model. These include unknown‐input observers that make use of the special systems structure as well as observers based on the observability canonical form with different embedding dimensions. The canonical form is computed by algebraic methods.
Process parameters optimization of double‐vacuum‐bag technology for carbon fiber/resin composites
Authors: Ren Liangliang , Zhang Deyuan 
Published: December 2024

AbstractDouble‐vacuum‐bag (DVB) process, as an effective out‐of‐autoclave (OoA) technology, can manufacture composite materials with low void content and high mechanical properties. Therefore, this paper aimed to achieve low void content, the effects of pressure difference between inner and outer bags, dwelling temperature, and dwelling time on the void of composite laminates were studied based on orthogonal experimental method. The void content and morphology of laminates were statistically analyzed, by observing the microscopic images of the samples on cross‐section. The results show that the pressure difference between the inner and outer bags has a significant impact on the void content and morphology, while the dwelling temperature and dwelling time have little effect. In addition, with the variance analysis and extreme difference analysis, the optimal process parameters were determined as follows: pressure difference between inner and outer bags was 0 MPa, dwelling temperature was 110°C, and dwelling time was 15 min. The void content of composite laminates manufactured under these parameters is 0.07%, less than 1% requirement for aerospace components, and interlaminar shear strength (ILSS) is 110 MPa, which is 54.93% higher than the single‐vacuum‐bag (SVB) process. Generally, the void content and ILSS reached the level of hot press process with 0.6 MPa.Highlights
Influence of different DVB process parameters on void were studied.
Void content manufactured with the optimal DVB process parameters was less than 1%.
ILSS of laminate with the optimal DVB process parameters was equal as hot press process.
Bio‐based epoxidized natural rubber nanocomposites for high‐performance tire tread applications
Authors: Zhao Luan , Liu Ling , Li Hanyu , Zhang Yuxi , Zhang Liqun 
Published: December 2024

AbstractIn this work, epoxidized natural rubber (ENR) with low epoxide degrees is synthesized through in situ epoxidation and then blended with TESPT‐modified silica to obtain the corresponding nanocomposites (ENR‐x/silica). It is found the filler‐rubber interaction is significantly enhanced by the ring‐opening reaction between silanol groups on silica and epoxy groups of ENR macromolecular chain. Therefore, wet‐skid resistance, fuel efficiency, abrasion resistance, and moduli of the ENR‐x/silica nanocomposites are superior to those of NR/silica nanocomposites. ENR‐15/silica demonstrates a balanced “magic triangle” performance, with wet‐skid resistance increasing by 74%, abrasion resistance improving by 17%, and rolling resistance decreasing by 29%, in relative to NR/silica.Highlights
ENR with low epoxide degrees is synthesized by in situ epoxidation.
Epoxy groups enhance the silica dispersion and filler–rubber interaction.
ENR‐15/silica shows the lowest rolling resistance.
Wet‐skid and abrasion resistance increase with increasing epoxide degree.
ENR/silica with TESPT composites show excellent performance as tire tread.
Effects of allosteric effectors on oxygen binding to crystals of hemoglobin in the R‐quaternary structure
Authors: Shibayama Naoya 
Published: December 2024

AbstractMuch is known about how allosteric effectors influence the equilibrium between the relaxed (R) and tense (T) states of hemoglobin (Hb), but little is known about how and to what extent the effectors lower the intrinsic O2 affinity of each allosteric state, especially the R‐state. Here, we provide a thorough characterization of the O2 equilibria of effector‐bound and unbound R‐quaternary form crystals of horse Hb without a quaternary structural switching. In the absence of effectors, R crystals of horse Hb were shown to bind O2 noncooperatively with a very high affinity virtually identical to that of R crystals of human Hb. We found that the effector bezafibrate (BZF) and its derivative L35 lower the overall O2 affinity of R crystals by approximately a factor of 3 and 2, respectively, while both maintaining noncooperative oxygenation. These effects are observed regardless of whether the effectors are co‐crystallized or soaked into the effector‐free protein crystals with a different lattice, confirming that the observed affinity reduction is induced by the BZF derivatives and not by crystal packing forces. Our findings, combined with available co‐crystal structural data, suggest that the BZF derivatives lower the O2 affinity of the R‐quaternary structure of Hb through structural constraints imposed by a quaternary shift slightly toward T. Additionally, since no co‐crystal of R‐state Hb with the effector inositol hexakisphosphate (IHP) is available, we only present an IHP‐soaking experiment showing little change in O2 affinity, and poor IHP binding to the R crystal structure of horse Hb is suggested.
Flexible Spline Models for Blinded Sample Size Reestimation in Event‐Driven Clinical Trials
Authors: Mori Tim , Komukai Sho , Hattori Satoshi , Friede Tim 
Published: December 2024

ABSTRACTIn event‐driven trials, the target power under a certain treatment effect is maintained as long as the required number of events is obtained. The misspecification of the survival function in the planning phase does not result in a loss of power. However, the trial might take longer than planned if the event rate is lower than assumed. Blinded sample size reestimation (BSSR) uses non‐comparative interim data to adjust the sample size if some planning assumptions are wrong. In the setting of an event‐driven trial, the sample size may be adjusted to maintain the chances to obtain the required number of events within the planned time frame. For the purpose of BSSR, the survival function is estimated based on the interim data and often needs to be extrapolated. The current practice is to fit standard parametric models, which may however not always be suitable. Here we propose a flexible spline‐based BSSR method. Specifically, we propose to carry out the extrapolation based on the Royston–Parmar spline model. To compare the proposed procedure with parametric approaches, we carried out a simulation study. Although parametric approaches might seriously over‐ or underestimate the expected number of events, the proposed flexible approach avoided such undesirable behavior. This is also observed in an application to a secondary progressive multiple sclerosis trial. Overall, if planning assumptions are wrong this more robust flexible BSSR method could help event‐driven designs to more accurately adjust recruitment numbers and to finish on time.
Optimal distributions of growing‐type initial perturbations for ensemble forecasts: Theory and application in the Lorenz‐96 model
Authors: Ji Chaopeng , Qin Bo , Mu Mu , Ma Junjie , Fang Xianghui , Feng Jie , Wang Qiang 
Published: December 2024

AbstractEnsemble forecasts are frequently utilized to assess the uncertainties of prediction systems. There is a consensus that generating initial perturbations with specific structures is more conducive to characterizing the growth dynamics of analysis errors, demonstrating higher forecast skills. However, the widely used methods, such as linear singular vectors (SVs) and orthogonal conditional nonlinear optimal perturbations (O‐CNOPs) exhibit strong linear‐assumption dependence and the overestimation of growing properties for analysis errors, respectively, severely limiting the ability to capture analysis errors and forecast skills. To tackle these challenges, a theoretical framework is established to solve the optimal distribution of the nonlinear growing‐type initial perturbations by variational inference (VI) incorporated with the concept of CNOPs, marked as VI‐CNOPs. As the distribution is obtained, diverse initial perturbations for ensemble forecasts can be easily sampled in it. To evaluate the reliability of VI‐CNOPs, a series of ensemble forecast experiments are then conducted using the Lorenz‐96 model. We compare the deterministic and probabilistic forecast skills of VI‐CNOPs, O‐CNOPs, and SVs under various optimization durations. The results reveal that, as the optimization durations extend, the forecast skills of VI‐CNOPs progressively improve, consistently outperforming O‐CNOPs and SVs. This trend remains consistent across various forecast lead times. Further analysis reveals that VI‐CNOPs more effectively capture the covariance matrix of analysis errors, aligning with the fundamental concept of perturbation generation methods for ensemble forecasts. Moreover, unlike O‐CNOPs and SVs, VI‐CNOPs do not require the utilization of adjoint and tangent linear models, largely expanding its application. These results indicate the novelty and efficacy of VI‐CNOPs for ensemble forecasts.
Simulation of a Three‐Nucleons System Transition on Quantum Circuits
Authors: Nigro Luca , Barbieri Carlo , Prati Enrico 
Published: December 2024

AbstractQuantum computers have proven to be effective in simulating many quantum systems. Simulating nuclear processes and state preparation poses significant challenges, even for traditional supercomputers. This study demonstrates the feasibility of a complete simulation of a nuclear transition, including the preparation of both ground and first excited states. To tackle the complexity of strong interactions between two and three nucleons, the states are modeled on the tritium nucleus. Both the initial and final states are represented using quantum circuits with variational quantum algorithms and inductive biases. Describing the spin‐isospin states requires four qubits, and a parameterized quantum circuit that exploits a total of 16 parameters is initialized. The estimated energy has a relative error of 2% for the ground state and 10% for the first excited state of the system. The simulation estimates the transition probability between the two states as a function of the dipole polarization angle. This work marks a first step toward leveraging digital quantum computers to simulate nuclear physics.
Spin Pumping in Epitaxial Ge1‐xSnx Alloys
Authors: Longo Emanuele , Concepción Omar , Mantovan Roberto , Fanciulli Marco , Myronov Maksym , Bonera Emiliano , Pedrini Jacopo , Buca Dan , Pezzoli Fabio 
Published: December 2024

AbstractThe use of Ge1‐xSnx semiconductor alloys is generating significant interest in the scientific community due to their precisely tunable Sn content. This tunability makes them particularly attractive for applications in photonics, electronics, and, more recently, spintronics. Room‐temperature emission and detection of spin currents are observed in Ge1‐xSnx/Co hybrids through spin‐pumping ferromagnetic resonance. Experiments conducted over a wide range of compositions and strains show that spin current injection is enhanced in Ge1‐xSnx solid solutions compared to elemental Ge. The magnetization dynamics reveal an intriguing scenario where the Gilbert damping constant and the spin mixing conductance display a non‐monotonic behavior. The maximum spin‐pumping efficiency occurs at a Sn molar fraction of ≈10 at.% and remains unaffected by the elastic strain built up in Ge1‐xSnx films through epitaxial growth on Ge‐buffered Si substrates. These findings highlight the non‐trivial dependence of alloy scattering in defining spin accumulation and relaxation mechanisms, providing insightful information on phenomena at the forefront of spintronics and quantum technology research.
Ultrastable Seawater Oxidation at Ampere‐level Current Densities with Corrosion‐resistant CoCO3/CoFe Layered Double Hydroxide Electrocatalyst
Authors: Yao Yongchao , Zou Chang , Sun Shengjun , Guo Yaxin , Hong Shaohuan , Cai Zhangping , Yang Chengli , Zhuang Weihua , Luo Fengming , Hamdy Mohamed S. , Ibrahim Fatma A. , Gong Feng , Li Yanan , Sun Xuping , Hu Wenchuang (Walter) 
Published: December 2024

AbstractHydrogen is an essential energy resource, playing a pivotal role in advancing a sustainable future. Electrolysis of seawater shows great potential for large‐scale hydrogen production but encounters challenges such as electrode corrosion caused by chlorine evolution. Herein, a durable CoCO3/CoFe layered double hydroxide (LDH) electrocatalyst is presented for alkaline seawater oxidation, showcasing resistance to corrosion and stable operation exceeding 1,000 h at a high current density of 1 A cm−2. The results indicate that CoCO3 within the electrocatalyst undergoes conversion into CoOOH and releases CO32− during electrolysis. The incorporation of CO32− within its layers and the anchoring of the electrocatalyst's surface prevent the adverse adsorption of chloride ions, enhancing resistance to chloride ion corrosion, thereby protecting the active sites of the electrocatalyst effectively.
Economic policy uncertainty and the Kimchi premium in the cryptocurrency market
Authors: Cho Dooyeon , Lee Kyung‐woo 
Published: December 2024

AbstractWe construct a new daily measure of uncertainty about economic policy for Korea. The economic policy uncertainty (EPU) index is extracted from the reporting about economic policy in major Korean newspapers. We then investigate how daily EPU affects the Kimchi premium, which is the ratio of the Bitcoin price in Korea to that in the United States, adjusted for the exchange rate. Our findings indicate that an increase in Korea's EPU makes Bitcoin more expensive in Korea, while the U.S. dollar strengthens against the Korean won. The stronger appreciation of the U.S. dollar outweighs the increase in Bitcoin prices, thereby lowering the Kimchi premium. Similarly, an increase in U.S. EPU has comparable but weaker effects. The appreciation of the U.S. dollar almost entirely offsets the higher relative price of Bitcoin in Korea, resulting in no significant impact on the Kimchi premium from changes in U.S. EPU. In addition, the results suggest that the Kimchi premium tends to rise with increased trading volume in Korea but decreases as trading volume increases in the United States. We also document that while the Kimchi premium is positively associated with Bitcoin price volatility in Korea, it is not significantly related to that in the United States.
Numerical treatments for peristaltic transport of Johnson‐Segalman nanofluid through a vertical divergence irregular channel in the presence of inclined magnetic field and double‐diffusive
Authors: Hussein Sameh A. , Ahmed Sameh E. , Arafa Anas A. M. , Elshekhipy Abdelhafeez A. 
Published: December 2024

AbstractThis paper presents a computational study for the peristaltic pumping within vertical irregular divergence channels filled with magnetic Johnson—Segalman nanofluid. Various configurations of the outer boundaries are considered, namely, square wave, multi‐sinusoidal wave, trapezoidal wave, and triangular wave. An inclined magnetic field together with nanoparticles and mass concentrations is considered. Influences of the Dufour and Soret numbers are examined, and the cases of low Reynolds number and long wavelength are applied. All the computations are obtained numerically using Mathematica symbolical software (ND‐Solve), and the obtained results are presented in terms of the axial velocity , heat transfer rate , nanoparticle fraction profile , concentration profile , temperature profile , extra stress tensor , pressure gradient , pressure rise , and stream function . The major outcomes revealed that the square wave shape gives higher pressure gradients near the inlet and outlet parts while the multi‐sinusoidal wave gives periodic behaviors of . Also, the maximizing in thermophoresis parameter is better to obtain a higher rate of heat transfer while the increase in thermo‐diffusion and diffusion thermo effects causes a reduction in the rate of heat transfer. The discipline of biological and medical engineering, particularly for nanofluid peristaltic pumps, can benefit from the practical uses of such a model, which can be used to simulate the small vessel transport of particles in hemodynamics.
Almost-Commutative Manifolds and Gauge Theories
Authors: van Suijlekom Walter D. 
Published: December 2024

AbstractIn this chapter we analyze the gauge theories corresponding (in the sense of Chap. 7) to a special class of noncommutative manifolds, to wit almost-commutative, or AC manifolds. We will see that this class leads to the usual gauge theories in physics. After identifying the gauge group, the gauge fields and the scalar fields, we compute the spectral action that yields the Lagrangian of physical interest.
Beyond the Standard Model: Pati–Salam Unification
Authors: van Suijlekom Walter D. 
Published: December 2024

AbstractOne of the pressing questions at this point is whether noncommutative geometry may point to new physics beyond the Standard Model. The success of the spectral construction of the Standard Model, predicting its particle content, including gauge fields, Higgs fields as well as a singlet whose vev gives Majorana mass to the right handed neutrino, is a strong signal that we are on the right track. However, the mismatch between the predicted range of the Higgs mass and the experimentally observed value suggests that we should reconsider the path we took.
Finite Real Noncommutative Spaces
Authors: van Suijlekom Walter D. 
Published: December 2024

AbstractIn this chapter, we will enrich the finite noncommutative spaces as analyzed in the previous chapter with a real structure. For one thing, this makes the definition of a finite spectral triple more symmetric by demanding the inner product space H be an $$A-A$$

A
-
A

-bimodule, rather than just a left A-module.