bluuebunny/crossref_metadata_2025 huggingface dataset:
Laminar swirling slender pipe flows
Authors: Sauer Vinicius M. , Fachini Fernando F.
Published: October 2024

Swirling flows are extensively used to enhance mixing in chemical and physical processes. Although many fundamental studies involve decaying laminar swirls in circular ducts with constant area—for which several theoretical descriptions exist—converging and diverging pipe sections are often employed, demanding the extension of the analysis to swirling laminar flows in pipes with varying areas. This work analytically investigates axial swirl decay in laminar axisymmetric flows in converging and diverging pipes at moderate Reynolds numbers. The theoretical model extends the classical theory for laminar low swirling flows in straight pipes with impermeable walls to pipes with slowly varying areas. Inlet Reynolds number and converging/diverging angle effects are analyzed for incompressible axisymmetric laminar flows in slender pipes (lengths much greater than the radius). Results show that diverging pipes enhance the swirl decay rate, whereas converging systems have a weakening effect for flows with the same inlet Reynolds number. Conversely, increasing the inlet angle in converging flows decreases the decay rate, whereas larger diverging pipe inlet angles promote swirl decay. A simplified eigenvalue analysis shows that the relationship between the swirl decay lengths in diverging (ℓd,div), straight (ℓd,st), and converging (ℓd,conv) pipes is given by ℓd,div<ℓd,st<ℓd,conv for flows with similar inlet Reynolds numbers. Comparisons with numerical simulations show that the model predictions are almost exact for nondimensional pipe lengths up to 5×10−2 times the inlet Reynolds number. Approximating the axial velocity profile through a fully developed function representative of laminar flows with heat transfer through the walls shows that the narrower axial velocity profile in diverging flows increases viscous effects, enhancing the swirl decay rate. On the contrary, the flatter axial velocity profile in converging pipes further extends the decay length.
A new variational characterization of the Fučik spectrum for the Kirchhoff-type problem and applications
Authors: Rong Ting , Li Fuyi
Published: October 2024

We focus on the equation −∫Ω|∇u|2Δu=α(u+)3+β(u−)3 in Ω with the boundary condition u = 0 on ∂Ω, where Ω is a smooth bounded domain in RN for N = 1, 2, 3, α,β∈R, u+ = max{u, 0} and u− = min{u, 0}. Denote the Fučik spectrum by Σ, which is defined as a set comprising those (α,β)∈R2 such that the above equation has a nontrivial solution. The main goal of this study is to provide a new variational characterization for a class of curves in Σ. As an application, we establish the existence results for nonresonance and resonance problems related to these curves.
Study on the model for shock wave and bubble load of deep-sea explosion
Authors: Xing Jin-Hao , Zhang A-Man , Wang Shi-Ping , Li Shi-Min , Liu Yun-Long
Published: October 2024

The accurate estimation of deep-sea explosion loads is challenging due to the extreme conditions such as the ultra-hydrostatic pressure. The traditional Geers–Hunter model has acceptable accuracy in calculating underwater explosion load in conventional water depth, but it is not effective in deep-sea explosions. The model established by Zhang is applied to the underwater explosion load calculation in ultra-deep water. The model's accuracy is validated by both the deep-sea and the conventional explosion experimental results published and the Eulerian finite element method numerical results. The results show that, compared to the Geers–Hunter model, the present model can not only accurately calculate the conventional conditions, but also has better accuracy for calculating deep-sea explosion shock wave and bubble load, by providing more accurate shock wave attenuation and smoother connection between shock wave stage and bubble pulsation stage in deep sea.
Mechanism of double droplets off-center impact
Authors: Liu Zhe , Shi Shi-Hua , Gao Shu-Rong , Wei Bo-Jian , Yang Yan-Ru , Wang Xiao-Dong
Published: October 2024

Dynamics of double-droplet off-centered impact on a superhydrophobic substrate is investigated. The effects of the distance between droplets, off-centered distance as well as the Weber number on the impact dynamics are systematically investigated by lattice Boltzmann method simulations. For the off-centered impact of double droplets, two distinct regions are identified, i.e., the contact time increasing region (TIR) and the decreasing region (TDR). For TIR, the liquid film exhibits a “butterfly-like” shape during the spreading and then recoils toward the center, while for TDR, the liquid film presents a “rod-like” shape and then retracts toward the ends of the rod, leading a pancake bounce pattern. Considering the mechanism of the redistribution of liquid volume and the asymmetric of the liquid film, the quantitative expression of contact time for TIR is established. Based on this, the mechanism of the interaction between droplets is further studied to calibrate the expression of the contact time by introducing the center distance between droplets, which is certificated to be used in a large range of distances between droplets, off-centered distance, and the Weber number.
Microscopic view on the polarization-resolved S-SHG intensity of the vapor/liquid interface of pure water
Authors: Le Breton G. , Loison C. , Vynck K. , Benichou E. , Bonhomme O.
Published: October 2024

Second harmonic generation (SHG) is a nonlinear optical phenomenon where two photons at the frequency ω combine to form a single photon at the second-harmonic frequency 2ω. Since that second-order process is very weak in bulk isotropic media, optical SHG responses of interfaces provide a powerful and versatile technique to probe the molecular structure and dynamics of liquid interfaces. Both local dipole contributions and non-local quadrupole contributions can be interesting to investigate different properties of the interface, such as the molecular orientation or the charge density. However, a major difficulty is to comprehend the link between the S-SHG intensity and molecular details. This article reports a numerical approach to model the polarization-resolved SHG intensities of a model vapor/liquid interface of pure water. The influence of the interfacial local environment on the hyperpolarizability is taken into account using quantum mechanical/molecular mechanics calculations. The numerical predictions are in very good agreement with experiments. We detail the hypotheses made during the modeling steps and discuss the impact of various factors on the modeled SHG intensities, including the description of the exciting field in the interfacial layer, the effect of neighboring molecules on the second-harmonic polarization, and the presence of an additional static electric field at the interface.
Fluid–structure interaction analysis of curved wedges entering into water
Authors: Sun Shi-Li , Sun Jia-Yu , Wang Shuang , Li Ying-Hong , Ren Hui-Long
Published: October 2024

The water entry of wedges with curvature differs significantly from that of linear wedges, which have been fully investigated and formulated. The safety and integrity of structures prompt an urgent investigation into the mechanism by which the curvature affects slamming loads and structural responses during water entry. This study examines the slamming force characteristics, pressure distributions, fluid jet evolutions, and structural response behaviors of two-dimensional curved wedge sections, considering five different curvatures and two panel thicknesses. A two-way coupling fluid–structure interaction (FSI) solver has been proposed within an open-source framework. The FSI solver was validated against published literature to ensure its high-fidelity. The small deadrise angle results in a more complicated time-domain characteristics for the slamming pressure, with a gradual transition from a single peak to a double peak. The half-peak pressure duration time were defined, and the quantitative results reveal that the hydroelastic effect of the linear wedge is significantly higher than the curved wedges. When considering the geometric curvature, the elastic wedges do not consistently reduce the peak slamming pressure and lengthen the pulse time. Additionally, large deformations generated by the panel vibrations alter the evolutionary pattern of the fluid jet. In contrast to the linear wedge, the structural responses of the curved wedges show distinctive two-stage behaviors.
Data-driven multi-objective optimization of aerodynamics and aeroacoustics in dual Savonius wind turbines using large eddy simulation and machine learning
Authors: Fatahian Hossein , Mishra Rakesh , Jackson Frankie. F. , Fatahian Esmaeel
Published: October 2024

Savonius rotor is a popular form of vertical-axis wind turbine (VAWT) for small-scale and urban applications because of its straightforward design and self-starting ability. Dual VAWTs present challenges in terms of wake interactions and noise, particularly in urban areas. Optimizing these parameters is essential for future wind energy adoption. This research is the first to analyze how the interaction of wakes from adjacent rotors, combined with a deflector, affects both the aerodynamic performance and noise levels of dual Savonius rotors. Large Eddy Simulation is applied, as it effectively captures detailed turbulent wind flows and their interactions with wind turbines. A multi-objective optimization method combining Machine Learning and Computational Fluid Dynamics (CFD) is developed to optimize rotors for maximum power efficiency and minimum noise, considering their wake interactions with a unique deflector system. First, the influence of geometric parameters on aerodynamics and aeroacoustics characteristics of rotors is analyzed, and the database is generated using Design of Experiment approach. Next, the CFD model is replaced by Artificial Neural Network (ANN) model established for predicting rotor performances. A Multi-Objective Genetic Algorithm method is used to optimize aerodynamics and aeroacoustics characteristics of rotors. Finally, optimal design parameters are identified from the Pareto front using the technique for order of preference by similarity to ideal solution decision-making method. The ANN model demonstrated high accuracy with an RANN2 of 0.995 and 0.971 for the average power coefficient (CP) and overall sound pressure level (OSPL) predictions, respectively. Multi-objective optimization revealed the best configuration of the deflector with bleed jets, improving the average CP up to 57.5% and reducing OSPL to an almost 5.2% compared to the dual rotor case at TSR = 0.8.
Dynamics of non-Newtonian droplets eccentrically impacting hydrophobic spherical surfaces
Authors: Cai Jialiang , Ma Jiliang , Chen Xiaoping , Liu Daoyin , Liang Cai , Pan Suyang
Published: October 2024

In this study, the dynamic behaviors of non-Newtonian fluid droplets with shear-thinning properties eccentrically impacting hydrophobic particle surfaces are investigated through a combination of numerical simulations and experiments. The simulation integrates the dynamic contact angle and a non-Newtonian fluid power-law model within the volume of fluid model framework. The effects of apparent viscosity (η), impact velocity (v0), and dimensionless eccentricity parameter (B) on the dynamic behaviors of non-Newtonian droplets are analyzed. Furthermore, the study offers insight into the progression of pressure distribution, kinetic energy, and liquid viscosity across droplets during the entire impact process. An energy balance analysis, which includes kinetic energy, surface energy, potential energy, and viscous dissipation, is employed to elucidate the fundamental physical mechanisms that govern the dynamics of eccentric impacts of non-Newtonian droplets. Finally, a model (Recr D* = −95.7 + 11 450.6e−B/0.18) is proposed to predict the adhesion or detachment of shear-thinning droplets eccentrically impacting hydrophobic particle surfaces.
Single-cell resolution of intestinal regeneration in pythons without crypts illuminates conserved vertebrate regenerative mechanisms
Authors: Westfall Aundrea K. , Gopalan Siddharth S. , Kay Jarren C. , Tippetts Trevor S. , Cervantes Margaret B. , Lackey Kimberly , Chowdhury Saiful M. , Pellegrino Mark W. , Castoe Todd A.
Published: October 2024

Canonical models of intestinal regeneration emphasize the critical role of the crypt stem cell niche to generate enterocytes that migrate to villus ends. Burmese pythons possess extreme intestinal regenerative capacity yet lack crypts, thus providing opportunities to identify noncanonical but potentially conserved mechanisms that expand our understanding of regenerative capacity in vertebrates, including humans. Here, we leverage single-nucleus RNA sequencing of fasted and postprandial python small intestine to identify the signaling pathways and cell–cell interactions underlying the python’s regenerative response. We find that python intestinal regeneration entails the activation of multiple conserved mechanisms of growth and stress response, including core lipid metabolism pathways and the unfolded protein response in intestinal enterocytes. Our single-cell resolution highlights extensive heterogeneity in mesenchymal cell population signaling and intercellular communication that directs major tissue restructuring and the shift out of a dormant fasted state by activating both embryonic developmental and wound healing pathways. We also identify distinct roles of BEST4+ enterocytes in coordinating key regenerative transitions via NOTCH signaling. Python intestinal regeneration shares key signaling features and molecules with mammalian gastric bypass, indicating that conserved regenerative programs are common to both. Our findings provide different insights into cooperative and conserved regenerative programs and intercellular interactions in vertebrates independent of crypts which have been otherwise obscured in model species where temporal phases of generative growth are limited to embryonic development or recovery from injury.
Effects of heating rate and sintering temperature on the tensile properties of sintered γ-Ti/Al nanoparticle chains
Authors: Zhang Huadian , Jiang Qingrui , Han Yiwei , Fiske Michael R , Edmunson Jennifer E , Jiang Shan
Published: October 2024

This paper presents the results of molecular dynamics simulations that were performed to numerically study the laser sintering process and mechanical behavior of γ-Ti/Al bimetallic alloy nanoparticles (NPs). The study systematically investigates the effects of heating rate and sintering temperature on the resultant uniaxial tensile performances of the sintered NPs. A chain model was formed by connecting three pre-equilibrated Ti/Al NPs via necks during solid-state sintering. The solid-state sintered chain samples were heated to 1798 K using four different heating rates (0.04, 0.2, 0.5, and 1.0 K ps−1). After high-temperature relaxation of selected sintering temperature cases (e.g. 398 K, 598 K, etc. with a 200 K interval) for 10 ns, the heat sintered chain samples underwent a solidification process with a cooling rate of 0.08 K ps−1 and maintained at 298 K for an additional 1 ns. The resulting sintered chain products were then subjected to uniaxial tension at a strain rate of 0.0001 ps−1. The thermodynamic properties and crystallographic deformation were investigated during the sintering and subsequent tension processes. Analysis of the yield strengths obtained from the tension tests revealed a statistically significant correlation between the tensile strength of the sintered NPs and the pre-established sintering temperatures at each temperature. This observation indicates that higher sintering temperatures strengthen the neck connections within the NP-chains, leading to greater tensile strength. The higher sintering temperatures can reinforce the neck during high-temperature relaxation. It is worth noting that the effect of heating rates on mechanical properties was less pronounced when the sintering temperature was constant.
The role of Rh spacer layer thickness on the noncollinear interlayer exchange coupling
Authors: Demirci Erdem , Aksu Perihan , Öztürk Mustafa
Published: October 2024

The relationship between noncollinear interlayer exchange coupling (IEC) and magnetic anisotropic behavior in Fe/Rh/Fe trilayers is studied in detail by using magneto-optical Kerr effect and anisotropic magnetoresistance techniques. It is found that the Rh spacer layer(SL) thickness strongly affect IEC and magnetic anisotropy in these trilayers. The role of Rh SL thickness is shown in the oscillatory behavior in the magnitude of the magnetic anisotropy, the transition from uniaxial to four-fold-like anisotropy, the shift of easy axis for magnetic anisotropy and the unusual increasing in the sheet resistance. As a outcome of this study we discuss the underlying mechanism based on the noncollinear IEC across the Fe/Rh/Fe interlayer. As a result, it has been shown that the noncollinear IEC can be controlled by the various Rh spacer thickness in nonmagnetic transition layer.
Efficacy of a hybrid take home and in class summative assessment for the postsecondary physics classroom
Authors: Stonaha Paul , Douglas Stephanie T
Published: October 2024

Assigning course grades to students requires obtaining accurate measures of the students’ understanding and knowledge of the topic. The induced stress from a traditional summative assessment is known to negatively impact student grades, confounding the connection between knowledge and test grades. Documented approaches to reduce stress during examinations can lead to a distracting testing environment (two-stage tests) or are subject to cheating (take-home tests). We have developed a hybrid take-home/in-class exam that avoids such difficulties. We present herein the responses from student surveys conducted after each exam. The results of the surveys indicate that the hybrid exam method reduces test anxiety while improving students’ self-reported mastery of physics, as compared to traditional in-class summative assessments. These findings are significant at the p < 0.05 level. Lastly, we discuss the difficulties encountered in applying this test approach.
Monte Carlo damage models of different complexity levels predict similar trends in radiation induced DNA damage
Authors: Thompson Shannon J , Prise Kevin M , McMahon Stephen J
Published: October 2024

Introduction. Ion therapies have an increased relative biological effectiveness (RBE) compared to x-rays, but this remains poorly quantified across different radiation qualities. Mechanistic models that simulate DNA damage and repair after irradiation could be used to help better quantify RBE. However, there is large variation in model design with the simulation detail and number of parameters required to accurately predict key biological endpoints remaining unclear. This work investigated damage models with varying detail to determine how different model features impact the predicted DNA damage. Methods. Damage models of reducing detail were designed in TOPAS-nBio and Medras investigating the inclusion of chemistry, realistic nuclear geometries, single strand break damage, and track structure. The nucleus models were irradiated with 1 Gy of protons across a range of linear energy transfers (LETs). Damage parameters in the models with reduced levels of simulation detail were fit to proton double strand break (DSB) yield predicted by the most detailed model. Irradiation of the optimised models with a range of radiation qualities was then simulated, before undergoing repair in the Medras biological response model. Results. Simplified damage models optimised to proton exposures predicted similar trends in DNA damage across radiation qualities. On average across radiation qualities, the simplified models experienced an 8% variation in DSB yield but a larger 28% variation in chromosome aberrations. Aberration differences became more prominent at higher LETs, with model features having an increasing impact on the distribution and therefore misrepair of DSBs. However, overall trends remained similar with better agreement likely achievable through repair model optimisation. Conclusion. Several model simplifications could be made without compromising key damage yield predictions, although changes in damage complexity and distribution were observed. This suggests simpler, more efficient models may be sufficient for initial radiation damage comparisons, if validated against experimental data.
IPEM topical report: the first UK survey of cone beam CT dose indices in radiotherapy verification imaging for adult patients
Authors: Wood Tim J , Davis Anne T , Earley James , Edyvean Sue , Findlay Una , Lindsay Rebecca , Plaistow Rosaleen , Williams Matthew
Published: October 2024

Cone beam CT is integral to most modern radiotherapy treatments. The application of daily and repeat CBCT imaging can lead to high imaging doses over a large volume of tissue that extends beyond the treatment site. Hence, it is important to ensure exposures are optimised to keep doses as low as reasonably achievable, whilst ensuring images are suitable for the clinical task. This IPEM topical report presents the results of the first UK survey of dose indices in radiotherapy CBCT. Dose measurements, as defined by the cone beam dose index (CBDIw), were collected along with protocol information for seven treatment sites. Where a range of optimised protocols were available in a centre, a sample of patient data demonstrating the variation in protocol use were requested. Protocol CBDIw values were determined from the average dosimetry data for each type of linear accelerator, and median CBDIw and scan length were calculated for each treatment site at each centre. Median CBDIw values were compared and summary statistics derived that enable the setting of national dose reference levels (DRLs). A total of 63 UK radiotherapy centres contributed data. The proposed CBDIw DRLs are; prostate 20.6 mGy, gynaecological 20.8 mGy, breast 5.0 mGy, 3D-lung 6.0 mGy, 4D-lung 11.8 mGy, brain 3.5 mGy and head/neck 4.2 mGy. However, large differences between models of imaging system were noted. Where centres had pro-active optimisation strategies in place, such as sized based protocols with selection criteria, dose reductions on the ‘average’ patient were possible compared with vendor defaults. Optimisation of scan length was noted in some clinical sites, with Elekta users tending to fit different collimators for prostate imaging (relatively short) compared with gynaecological treatments (longest). This contrasts with most Varian users who apply the default scan length in most cases.
Optimisation of cone beam CT radiotherapy imaging protocols using a novel 3D printed head and neck anthropomorphic phantom
Authors: Alzahrani Meshal , O’Hara Christopher , Bird David , Baldwin Jack P C , Naisbit Mitchell , Teh Irvin , Broadbent David A , Al-Qaisieh Bashar , Johnstone Emily , Speight Richard
Published: October 2024

Objective. This study aimed to optimise Cone Beam Computed Tomography (CBCT) protocols for head and neck (H&N) radiotherapy treatments using a 3D printed anthropomorphic phantom. It focused on precise patient positioning in conventional treatment and adaptive radiotherapy (ART). Approach. Ten CBCT protocols were evaluated with the 3D-printed H&N anthropomorphic phantom, including one baseline protocol currently used at our centre and nine new protocols. Adjustments were made to milliamperage and exposure time to explore their impact on radiation dose and image quality. Additionally, the effect on image quality of varying the scatter correction parameter for each of the protocols was assessed. Each protocol was compared against a reference CT scan. Usability was assessed by three Clinical Scientists using a Likert scale, and statistical validation was performed on the findings. Main results. The work revealed variability in the effectiveness of protocols. Protocols optimised for lower radiation exposure maintained sufficient image quality for patient setup in a conventional radiotherapy pathway, suggesting the potential for reducing patient radiation dose by over 50% without compromising efficacy. Optimising ART protocols involves balancing accuracy across brain, bone, and soft tissue, as no single protocol or scatter correction parameter achieves optimal results for all simultaneously. Significance. This study underscores the importance of optimising CBCT protocols in H&N radiotherapy. Our findings highlight the potential to maintain the usability of CBCT for bony registration in patient setup while significantly reducing the radiation dose, emphasizing the significance of optimising imaging protocols for the task in hand (registering to soft tissue or bone) and aligning with the as low as reasonably achievable principle. More studies are needed to assess these protocols for ART, including CBCT dose measurements and CT comparisons. Furthermore, the novel 3D printed anthropomorphic phantom demonstrated to be a useful tool when optimising CBCT protocols.
Deep optimal experimental design for parameter estimation problems
Authors: Siddiqui Md Shahriar Rahim , Rahmim Arman , Haber Eldad
Published: October 2024

Optimal experimental design is a well studied field in applied science and engineering. Techniques for estimating such a design are commonly used within the framework of parameter estimation. Nonetheless, in recent years parameter estimation techniques are changing rapidly with the introduction of deep learning techniques to replace traditional estimation methods. This in turn requires the adaptation of optimal experimental design that is associated with these new techniques. In this paper we investigate a new experimental design methodology that uses deep learning. We show that the training of a network as a Likelihood Free Estimator can be used to significantly simplify the design process and circumvent the need for the computationally expensive bi-level optimization problem that is inherent in optimal experimental design for non-linear systems. Furthermore, deep design improves the quality of the recovery process for parameter estimation problems. As proof of concept we apply our methodology to two different systems of Ordinary Differential equations.
Wide band high gain modified-folded-wave-guide slow wave structure for millimeter-wave traveling wave tube amplifier in 6G and beyond back-haul communications
Authors: C Surya Prasath , Stanislaus Richards Joe
Published: October 2024

Millimeter-wave technology is crucial in telecommunications as it enables higher bandwidths and faster data transfer. V-band represents frequencies ranging from 50 to 75 GHz and is used for short-range back-haul communication, defense radar, inter-satellite communications, and space debris detection. Folded waveguide slow-wave structures (FWG-SWS) are an excellent choice for V-band amplifiers due to their wide bandwidths, large gain, and ease of fabrication using modern lithographic processes. This article presents a modified folded waveguide slow-wave structure (MFW-SWS) for V-band traveling wave tube amplifiers (TWTAs) desirable for multi-gigabit 6G and beyond back-haul communications. The MFW slow-wave structure is an FWG-SWS variant that supports an increased RF phase velocity, accommodating additional SWS length for much-improved amplification. The dispersion analysis effectively provides a 15% operational bandwidth ranging from 64–74 GHz with a reduced phase velocity of three-tenths the speed of light apt for enhanced beam-wave interactions. The two-section SWS has independent attenuators designed to provide over 20 dB attenuation throughout the functional bandwidth effortlessly. Additional wave-guide transitions are introduced to achieve the best attenuation characteristics. Along the axis of the SWS, a square beam tunnel is employed to support a 26 kV round electron beam with a beam current of 70 mA. To contain the electron beam within the beam tunnel, this study used a focusing mechanism with a constant magnetic field of 0.25T, which is highly appropriate for miniaturization and large-scale implementation in 6G back-haul towers. Particle-in-cell (PIC) simulations were performed using the CST (Computer Simulation Technology) Studio Suite, and a gain of over 26 dB with an output power of 50 W was successfully attained across the operational bandwidth.
Antenna Optimization Using Metamaterials
Authors: Karthik Reddy G , Vijetha T , Manoj Kumar GVS , Babu Syam , Babaiah Ch.
Published: October 2024

Metamaterials are artificial structures engineered to exhibit electromagnetic properties not found in natural materials. These materials offer a diverse range of characteristics, including negative refractive index, reverse radiation, and electromagnetic cloaking. These unique properties find applications in microwave and optical domains, enabling improvements in antenna performance, the design of microwave filters, and the creation of flat optical lenses, among others. This study focuses on utilizing metamaterials to enhance antenna performance by boosting gain, reducing mutual coupling between MIMO antennas, converting polarization, and decreasing radar cross-section (RCS). The primary performance metric considered in this investigation is gain enhancement.
Designing efficient bird-like flapping-wing aerial vehicles: insights from aviation perspective
Authors: Ma Dongfu , Song Bifeng , Gao Shijin , Xue Dong , Xuan Jianlin
Published: October 2024

Bird-like flapping-wing aerial vehicles (BFAVs) have attracted significant attention due to their advantages in endurance, range, and load capacity. For a long time, biologists have been studying the enigma of bird flight to understand its mechanism. In contrast, aviation designers focus more on bionic flight systems. This paper presents a comprehensive review of the development of BFAV design. The study aims to provide insights into building a flyable model from the perspective of aviation designers, focusing on the methods in the process of overall design, flapping wing design and drive system design. The review examines the annual progress of flight-capable BFAVs, analyzing changes in prototype size and performance over the years. Additionally, the paper highlights various applications of these vehicles. Furthermore, it discusses the challenges encountered in BFAV design and proposes several possible directions for future research, including perfecting design methods, improving component performance, and promoting practical application. This review will provide essential guidelines and insights for designing BFAVs with higher performance.
Uvarov perturbations for matrix orthogonal polynomials
Authors: Ariznabarreta Gerardo , García-Ardila Juan , Mañas Manuel , Marcellán Francisco
Published: October 2024

Additive perturbations, specifically matrix Uvarov transformations for matrix orthogonal polynomials, are under consideration. Christoffel–Uvarov formulas are deduced for the perturbed biorthogonal families, along with their matrix norms. These formulations are expressed in terms of the spectral jets of the Christoffel–Darboux kernels.
Guinea pig spermatozoa adhesion to an immobilized fibronectin matrix alters their physiology and increases their survival
Authors: Jorge-Cruz Coral Y , Roa-Espitia Ana L , Hernández-González Enrique O
Published: October 2024

Isthmus is the region of the oviduct considered a reservoir for spermatozoa, where they are retained and released synchronously with ovulation. Integrins mediate this interaction, and it is suggested that they regulate the viability and capacitation of spermatozoa. Spermatozoa retained in the oviductal epithelial cells show specific characteristics: normal morphology, intact acrosome and plasma membrane, no DNA fragmentation, and low levels of intracellular Ca2+, and protein phosphorylation at Tyr. This work aimed to define spermatozoa’s ability to adhere to an immobilized fibronectin matrix and its effects on their viability and capacitation. We found that guinea pig spermatozoa showed a high affinity for adhering to an immobilized fibronectin matrix but not to those made up of type 1 collagen or laminin. This interaction was mediated by integrins that recognize the RGD domain. Spermatozoa adhered to an immobilized fibronectin matrix were maintained in a state of low capacitation: low levels of intracellular concentration of Ca2+, protein phosphorylation in Tyr, and F-actin. Also, spermatozoa kept their plasma membrane and acrosome intact, flagellum beating and showed low activation of caspases 3/7. The spermatozoa adhered to the immobilized fibronectin matrix, gradually detached, forming rosettes and did not undergo a spontaneous acrosomal reaction but were capable of experiencing a progesterone-induced acrosomal reaction. In conclusion, the adhesion of spermatozoa to an immobilized fibronectin matrix alters the physiology of the spermatozoa, keeping them in a steady state of capacitation, increasing their viability in a similar way to what was reported for spermatozoa adhered to oviductal epithelial cells.
Interventions Targeting the Mental Health and Well-being of Care-Experienced Children and Young People: Mixed-Methods Systematic Review with Stakeholder Consultation to Inform Transportability and Adaptability to UK Context
Authors: Evans Rhiannon , MacDonald Sarah , Trubey Rob , Melendez-Torres G J , Robling Michael , Willis Simone , Boffey Maria , Wooders Charlotte , Vinnicombe Soo , Noyes Jane
Published: October 2024

Care-experienced children and young people are at increased risk of poor mental health and well-being, and suicide-related outcomes. There is an evidence-base for intervention effectiveness, but this is primarily from the USA. The present systematic review synthesised evidence for international interventions, exploring potential transportability and adaptability to the UK. We constructed an evidence map, and syntheses of intervention effectiveness, process evaluations and economic evaluations. We conducted seven stakeholder consultations with care-experienced young people, carers and professionals, to appraise transportability and adaptability. We identified sixty-four interventions, with 124 associated study reports. Seventy-seven were from the USA. There was limited effectiveness in targeting mental health, although there were promising approaches. Few approaches targeted well-being and suicide. Context factors, identified by the review and confirmed by stakeholders, may inhibit delivery: insufficient resources; time, emotional and cognitive burden; challenging interprofessional relationships; non-responsiveness to young people’s needs; and discounting of carers’ knowledge. Stakeholders recommended peer mentoring by other care-experienced individuals and system-change models that facilitate an attachment and/or trauma-informed ethos. Adaptation of existing approaches may be required to account for the context factors. Further intervention work is needed to target well-being and suicide.
Clinical and genetic landscape of optic atrophy in 826 families: insights from 50 nuclear genes
Authors: Zheng Yuxi , Wang Panfeng , Li Shiqiang , Long Yuxi , Jiang Yi , Guo Dongwei , Jia Xiaoyun , Liu Mengchu , Zeng Yiyan , Xiao Xueshan , Hejtmancik J Fielding , Zhang Qingjiong , Sun Wenmin
Published: October 2024

Hereditary optic neuropathies (HON) are a group of diseases due to genetic defects either in mitochondria or in nuclear genomes. The increasing availability of genetic testing has expanded a broader genetic and phenotypic spectrum of HON than previously recognized. To provide systematic insight into the genetic and phenotypic landscape of HON attributed to 50 nuclear genes, we conducted genetic analysis on part of 4776 index patients with clinical diagnosis of HON following our previous study on 1516 probands with Leber hereditary optic neuropathy (LHON) and mitochondrial DNA variants. Exome sequencing was performed in 473 patients diagnosed with nuclear gene-related HON (nHON) and 353 cases with unsolved LHON. Sequencing and variant interpretation in 50 causative nuclear genes indicated that the diagnostic yield of exome sequencing for nHON was 31.50% (149/473), while it was markedly lower at 1.42% (5/353) for LHON patients without primary mtDNA mutations. The top five implicated genes causing nHON in our in-house cohort, OPA1, WFS1, FDXR, ACO2, and AFG3L2, account for 82.46% of mutations. Although OPA1 was the most prevalent causative gene of nHON in both our cohort (53.25%) and literature review (37.09%), the prevalence of OPA1, WFS1, and FDXR differed significantly between our in-house cohort and the literature review (P-adjusted<0.001). Fundus changes in nHON could be stratified into three categories, the most common is optic atrophy at the examination (78.79%), the rarest is LHON-like optic atrophy (3.64%), and the intermediate is optic atrophy with concurrent retinal degeneration (17.57%), which was an independent risk factor for visual prognosis in nHON. A systematic genotype-phenotype analysis highlighted different genetic contributions for ocular, extraocular neurological, and extraocular non-neurological phenotypes. In addition, systemic variant analysis at the individual gene level suggested a revised interpretation of the pathogenicity of a WFS1 heterozygous truncation variant.

This study provides a panoramic summary of both the genetic and phenotypic profiles of HON in real-world studies and literature. The category for nHON fundus phenotypes is built for future studies on molecular mechanisms underlying HON and targeted therapies. In addition to routine ophthalmic examinations, careful examination of the extraocular symptoms and meaningful genetic counseling are warranted for patients with nHON.
Applications and analyses of ammonia slip control based on precise ammonia injection technologies guided by big data
Authors: Cao Lili , Zhang Jun
Published: October 2024

After the implementation of ultra-low emission policies, the pollutant emissions from the coal-fired power generation systems in China have been further reduced, which creates more critical requirements for the control accuracies of denitrification systems using selective catalytic reduction technology and controls of ammonia slip. This article presents big data-based technologies for controlling ammonia slip, through precise ammonia injections, which were applied and demonstrated for a flue gas denitrification system of a Chinese coal-fired power plant. Through examinations and analyses of the basic operating conditions of the unit and parameters, such as NOx emission control efficiency, ammonia injection amount of the denitrification system, and non-uniformity of NOx concentrations in the denitrification zone were compared before and after the implementation of these technologies, the outcome proves that this artificial intelligence algorithm based on big data can effectively solve the automatic control problem of denitrification system under complex working conditions such as varied unit loads, day and night operation changed coal source. In addition to the effective controls of the ammonia slip of the system, the controls of NOx emission of the system become more stabilized, creating a successful example for wider applications of these precise ammonia injection control technologies in the future. Analyses show that NOx non-uniformities can be reduced by more than 50% under both stable and variable load conditions. NOx fluctuations at the unit outlet are tightly controlled within ±10 mg/Nm3 under variable load conditions and within ±5 mg/Nm3 under stable conditions. The average ammonia injection amounts under various load conditions have decreased by 15.7%.
‘A hundred paper cuts over my vulva’: a patient’s experience of vulval lichen sclerosus
Authors: Lanthier Jaclyn , Clarke Louise , Simpson Rosalind
Published: October 2024

This patient viewpoint illustrates the difficulties experienced by women in seeking diagnosis and treatment for vulval lichen sclerosus. The author vividly describes anatomical changes and the impacts on mental health and quality of life. In addition, this viewpoint highlights the importance of patient involvement in research, education and support.
Extending insights from LeDoux: using movies to study subjective, clinically meaningful experiences in neuroscience
Authors: Kirk Peter A , Pine Daniel S , Kircanski Katharina
Published: October 2024

Neuroscience research with public health relevance to emotional disorders examines brain–behavior relations. Joe LeDoux’s legacy advances these efforts in ways that remain truly unique. While recognized for his basic science research, he also inspires applied researchers, guiding an agenda for clinical scientists: understanding the pathophysiology of altered subjective experiences in emotional disorders. For brain imaging, movie-watching approaches help clinicians realize this agenda due to movies’ relative strength in evoking rich, meaningful subjective experiences. Here, we describe methodological advances in movie-watching paradigms that might sustain LeDoux’s impact by facilitating the discovery of neural mechanisms generating complex emotional responses. Of note, while linking subjective emotion to pathophysiology is a first step, innovations in movie-watching designs, especially involving therapeutic techniques for emotional disorders, can boost clinical application. Leveraging research on pathophysiology to generate novel therapy reflects the clinical legacy sustained through Joe LeDoux’s rousing career.
Comparison of daytime and nighttime supine gastroesophageal reflux by pH monitoring of individuals with clinical suspicion of gastroesophageal reflux disease
Authors: de Pádua Filipe , Herbella Fernando A M , Del Grande Leonardo M , Schlottmann Francisco , Patti Marco G
Published: October 2024

This study aims to compare pHmetric characteristics of diurnal and nocturnal supine reflux. We studied 500 consecutive individuals with clinical suspicion of gastroesophageal reflux disease (GERD) who underwent esophageal high-resolution manometry and prolonged ambulatory pH monitoring. Patients were classified with supine GERD pattern when the percentage of acid reflux time in the supine position was equal to or greater than 2.2%. Data on acid reflux in the supine position during daytime and nighttime recumbency were: (i) acid exposure time, (ii) number of reflux episodes, (iii) longest reflux episode, (iv) interval between the last meal and the supine position, (v) interval between the supine position and the first acid reflux episode, and (vi) reported symptoms. Of the 500 evaluated patients, 238 (48%) had GERD. Among these, supine pattern was observed in 134 (56%) patients, bipositional in 53 (23%), and orthostatic in 51 (21%). In patients with daytime recumbency, 112 (51% of 217) were pathological refluxers, with a mean DeMeester score of 45 ± 26. Total acid exposure time (P = 0.8) and reported Symptom Index (P = 0.2) did not differ depending on the period, whether diurnal or nocturnal. All other pHmetric parameters were lower during daytime recumbency. In conclusion, diurnal supine reflux has similar acid exposure time and temporal correlation between symptoms and reflux episodes as nocturnal supine reflux. Other pHmetric parameters are lower for diurnal supine reflux.
Psychological factors and blood pressure responses to acute stress in women with takotsubo syndrome: an exploratory study
Authors: Ouaddi Sara , Keirns Natalie G , Lee Sharon Y , Dunsiger Shira , Gathright Emily , Burg Matthew , Breault Christopher , Tripolone Janice , Salmoirago-Blotcher Elena
Published: October 2024

Aims

This secondary analysis aimed to (i) describe psychological resources and distress in women with takotsubo syndrome (TS) and (ii) explore whether such factors affect blood pressure (BP) responses to acute mental stress.

Methods and results

Participants were 47 women consecutively enrolled in an ongoing study examining the prognostic significance of stress reactivity in TS. Psychological resources (resilience and adaptive coping) and distress [depression, anxiety, post-traumatic stress disorder (PTSD), and perceived stress] were self-reported using validated questionnaires <12 weeks after TS. Using a standardized protocol, systolic BP (SBP) and diastolic BP (DBP) (mmHg) were measured every 5 min during baseline (10 min), mental stress (10 min), and recovery (20 min). Associations of psychological resources and distress (high vs. low composite scores), respectively, with BP during mental stress and recovery (change from baseline), were examined using one-way analyses of covariance (covariates: age and anti-hypertensive medications). Given the study’s exploratory nature, results are shown as effect sizes. On average, women (Mage = 64.3 years) had high perceived stress, anxiety, and PTSD symptoms and low resilience. Women with high (vs. low) psychological distress displayed less complete SBP (d = 0.57) and DBP (d = 0.33) recovery to baseline. Women with low (vs. high) psychological resources demonstrated lower SBP responses during mental stress (d = −0.26) alongside a more complete SBP recovery (d = 0.30).

Conclusion

Female survivors of TS with high psychological distress exhibited impaired BP recovery following acute mental stress. While the prognostic significance of impaired BP recovery from mental stress remains to be determined in longitudinal studies, this finding could help identify TS survivors at risk for recurrence.
Educational differences in alcohol-related morbidity and the role of working conditions: a Swedish register-based cohort study
Authors: Almroth Melody , Hemmingsson Tomas , Falkstedt Daniel , Carlsson Emma , Kjellberg Katarina , Thern Emelie
Published: October 2024

This study aims to investigate the relationship between education and alcohol-related morbidity and the role that low job control and heavy physical workload play in explaining these associations among men and women in Sweden. This register-based cohort study (SWIP cohort) includes over three million individuals registered in Sweden in 2005. Job control and physical workload were measured using a job exposure matrix linked to the index person based on their registered occupation at baseline. Alcohol-related morbidity was measured through diagnoses in the national patient registers between 2006 and 2020. Cox proportional hazards regression models were built to estimate associations between education and alcohol-related morbidity. Reductions in hazard ratios (HRs) were calculated after adjusting for job control, physical workload, and other covariates. Models were also stratified by sex. Lower levels of education predicted a higher risk of alcohol-related morbidity (HR: 2.55 95% confidence interval: 2.49–2.62 for the lowest educated compared to the highest). Low job control and heavy physical workload both played roles in explaining educational differences in alcohol-related morbidity even after accounting for sociodemographic and health factors (15.1% attenuation for job control and 18.3% for physical workload among the lowest educated). Physical workload explained a larger proportion of the associations among men compared to women. Lower levels of education were associated with an increased risk of alcohol-related morbidity and working conditions partly explained these associations beyond what was explained by sociodemographic and health factors. Improving working conditions could therefore prevent some cases of alcohol-related morbidity.