bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and Research of the Grasping Force Feedback Mechanism of Flexible Surgical Robots
Authors: Wang Fuhao , Wang Ye , Pan Qiqi , Luo Jingjing , Wang Hongbo , Kang Xiaoyang , Zhang Xueze 
Published: August 2024

ABSTRACTBackgroundRobot‐assisted microsurgery (RAMS) is gradually becoming the preferred method for some delicate surgical procedures. However, the lack of haptic feedback reduces the safety of the surgery. Surgeons are unable to feel the grasping force between surgical instruments and the patient's tissues, which can easily lead to grasping failure or tissue damage.MethodsThis paper proposes a tendon‐driven grasping force feedback mechanism, consisting of a follower hand and a leader hand, to address the lack of grasping force feedback in flexible surgical robots. Considering the friction in the tendon transmission process, a grasping force estimation model is established for the follower hand. The admittance control model is designed for force/position control of the leader hand.ResultsThrough experimental validation, it has been confirmed that the grasping force sensing range of the follower hand is 0.5–5 N, with a sensing accuracy of 0.3 N. The leader hand is capable of providing feedback forces in the range of 0–5 N, with a static force accuracy of 0.1 N.ConclusionsThe designed mechanism and control strategy can provide the grasping force feedback function. Future work will focus on improving force feedback performance.Trial RegistrationThis research has no clinical trials.
Adaptive robust safety‐critical control of switched systems via single barrier function
Authors: Huang Chunxiao , Long Lijun 
Published: August 2024

SummaryThis paper addresses the problem of adaptive robust safety‐critical control (ARSCC) for switched systems, where the safety of subsystems is not necessary. A novel ARSCC framework and an executable algorithm are presented to solve the ARSCC problem by finding a switching signal and controllers of subsystems. To estimate uncertainties, a novel switched piecewise‐constant adaptive law is presented, which guarantees a pre‐computable estimation error boundary. A single barrier function (SBF) method is proposed to ensure safety of switched systems with uncertainties, where the safety of subsystems is satisfied only in some subregion of a given safe set, instead of the whole safe set. Based on the SBF method, a novel state‐dependent switching law possessing different dwell times for different subsystems, is established to orchestrate the switching among potentially unsafe subsystems. As a special case of the SBF method, a common barrier function method is presented to achieve safety of switched systems with uncertainties under switching signals with given dwell times. In addition, some sufficient conditions are derived to obtain safety and asymptotic stability for switched systems with uncertainties by combining SBF and single Lyapunov function. Finally, a switched RLC circuit system is given to illustrate the effectiveness of the theoretical results.
eZ flow metrics: Using z‐scores to estimate deviations from natural flow in the Colorado River below Glen Canyon Dam
Authors: Palmquist Emily C. , Deemer Bridget R. , Metcalfe Anya N. , Kennedy Theodore A. , Bair Lucas S. , Fairley Helen C. , Grams Paul E. , Sankey Joel B. , Yackulic Charles B. 
Published: August 2024

AbstractRiver flow patterns are primary drivers of lotic ecosystems, and hundreds of metrics have been developed to quantify flow attributes. Although existing metrics have been a powerful tool in designing environmental flows, they are often developed with specific resources in mind and are rarely directly comparable with each other (i.e., units are often different). Here, we focus on natural flows as the resource of interest and develop z‐score metrics that measure the naturalness of regulated flows, incorporating natural means and interannual variation. These “eZ metrics” summarize whole year, subdaily, and functional flow patterns as standard deviations from natural such that their values are directly comparable. We illustrate their utility with a case study from the Colorado River downstream of Glen Canyon Dam in Arizona, USA. We calculated metrics for 1964–2022, spanning >5 decades of changing water policy, hydropower generation, and flow experimentation. We evaluate four options for estimating natural baseline flows. Across metrics, we found that subdaily stage variation deviated the most from baseline. Flows to satisfy regional water policy and power demands altered metrics more than designer flows (which target specific resource outcomes), and years with low water releases were closest to natural. Most of the designer flows have not made flow patterns more natural, due to incorrect seasonal timing, small magnitude, or short duration. By explicitly considering interannual variability and quantifying how regulated flows differ from natural using standard deviations, these metrics can inform management when the goal is to restore a natural flow regime.
The devil's staircase for chip‐firing on random graphs and on graphons
Authors: Kiss Viktor , Levine Lionel , Tóthmérész Lilla 
Published: August 2024

AbstractWe study the behavior of the activity of the parallel chip‐firing upon increasing the number of chips on an Erdős–Rényi random graph. We show that in various situations the resulting activity diagrams converge to a devil's staircase as we increase the number of vertices. Such a phenomenon was proved in an earlier paper by Levine for complete graphs, by relating the activity to the rotation number of a cycle map. Our method in this article is to generalize the parallel chip‐firing to graphons. Then we show that the earlier results on complete graphs generalize to constant graphons. Moreover, we prove a continuity result for the activity on graphons. These statements enable us to prove results on the activity of the parallel chip‐firing on large random graphs. We also address several problems concerning chip‐firing on graphons, and pose open problems. In particular, we show that the activity of a chip configuration on a graphon does not necessarily exist, but it does exist for every chip configuration on a large class of graphons.
Production and Evaluation of Hydroxypropyl Starch as a Viscosifying Agent for Enhanced Oil Recovery
Authors: de Aguiar Kelly Lúcia Nazareth Pinho , de Sá Gomes Karen , da Silva Licht Matheus Ferreira , Palermo Luiz Carlos Magalhães , Mansur Claudia Regina Elias 
Published: August 2024

AbstractIn this study, starch was obtained from rice wastes and the maximum extraction yield was 90.95 %. Chemical modification reactions were carried out by hydroxypropylation to obtain a modified starch extract, named 005A, soluble in synthetic injection brine. Extract 005A had a modified starch concentration of 1.24 %, with a pseudoplastic rheological profile and viscosities of 325.54 cP and 121.03 cP at temperatures of 25 and 60 °C, respectively. The application of extract 005A was evaluated by injectivity/filterability tests, which indicated a good filtration rate and viscosity loss of 3.81 % when passing the fluid through the filtering membrane. Stability tests indicated that the 005A extract had a viscosity loss of 21.35 %, at the temperature of 60 °C, after 60 days. The application of this extract enabled additional mineral oil recovery of 12.19 % in simulated core flooding tests. Therefore, the extract of hydroxypropyl starch is a promising viscosifying agent for Enhanced Oil Recovery (EOR) fluids.
Preparation of UV Curable Resins and their Toughening Effect on Bisphenol A‐Type Epoxy Acrylate
Authors: Jiang Honggang , Chen Jiahui , Zou Jiajun , Cui Yanyan , Ai Jiaoyan , Song Lina , Liu Baohua 
Published: August 2024

AbstractUV‐curable oligomers were synthesized by the reaction of ethylene glycol (EG) or 1,4‐butanediol (BDO) with isophorone diisocyanate (IPDI), and then terminated with hydroxyethyl acrylate (HEA). The chemical structures and molecular weight of the two oligomers were analyzed by Fourier transform infrared spectroscopy (FT‐IR), nuclear magnetic resonance (1H NMR and 13C NMR) and high performance liquid chromatography (HPLC). The obtained UV‐curable oligomers were separately mixed with bisphenol A‐type epoxy acrylate (EA) in different mass ratios. The resulting mixture was then mixed with the active diluent tetrahydrofuran acrylate (THFA) and the photoinitiator ethyl 2,4,6‐trimethylbenzoylphosphonate (TPO‐L) for UV curing. The curing reactions were performed at UV light intensity of 120 mW/cm2. The unsaturation conversion was monitored by real‐time infrared spectroscopy (real‐time FT‐IR). The mechanical properties and coating properties of the UV‐cured products were analyzed. The results showed that the synthesized UV‐curable oligomers had good toughening effect on EA, and the tensile strength of EA was also improved.
Cadmium Exposure in Male Rats Results in Ovarian Granulosa Cell Apoptosis in Female Offspring and Paternal Genetic Effects
Authors: Li Qingyu , Li Yuchen , Zhu Jianlin , Liu Zhangpin , Sun Yi , Lv Yake , Li Jingwen , Luo Lingfeng , Zhang Chenyun , Zhang Wenchang 
Published: August 2024

ABSTRACTThe aim of this study was to investigate whether the damage to male offspring induced by cadmium (Cd) exposure during embryonic period leads to the apoptosis of ovarian granulosa cells (OGCs) in the next generation of female offspring, and whether this apoptosis in the offspring was due to paternal genetic effects. Pregnant Sprague–Dawley (SD) rats were exposed to CdCl2 (0, 0.5, 2.0, or 8.0 mg/kg) by gavage daily for 20 days to produce the filial 1 (F1) generation. F1 males were mated with newly purchased females to produce the F2 generation, and the F3 generation was generated in the same way. No apoptotic bodies were observed in the OGCs of either the F2 or F3 generation as shown by electron microscopy, and a reduced OGC apoptosis rate (detected by flow cytometry) was observed in F2 OGCs from the Cd‐exposed group. Moreover, the mRNA (qRT‐PCR) levels of Bax and Bcl‐2 and the protein (western blotting) level of pro‐caspase‐8 increased in the F2 generation (p < 0.05). The expression of apoptosis‐related miRNAs (qRT‐PCR) and methylation of apoptosis‐related genes (determined via bisulfite‐sequencing PCR) in OGCs were further determined. Compared with those of the controls, the expression patterns of microRNAs (miRNAs) in the F2 offspring were different in the Cd‐exposed group. The miR‐92a‐2‐5p expression levels were decreased in both the F2 and F3 generations (p < 0.05), while the average methylation level of apoptosis‐related genes did not change significantly (except for individual loci). In summary, this study showed that the paternal genetic intergenerational effect of male Cd exposure during embryonic period induced apoptosis of OGCs in the offspring was weakened, and the transgenerational effect disappeared; nevertheless, intergenerational and transgenerational changes in apoptosis‐related genes, epigenetic modifications, DNA methylation, and miRNAs were observed, and may be important for understanding the homeostatic mechanisms of the body to alleviate the intergenerational transmission of Cd‐induced damage.
Overview of the various methods used to assess walking ability in broiler chickens
Authors: Wurtz Kaitlin E. , Riber Anja B. 
Published: August 2024

AbstractBackgroundWalking ability is a highly important animal‐based indicator of welfare in broilers that warrants monitoring across commercial production.MethodsA review of the technical and scientific literature on existing methods for assessing walking ability in broilers was conducted, and the reliability, validity and feasibility of the different methods were assessed when relevant information was available.ResultsVisual gait scoring has high validity, minimal equipment needs and is relatively quick to perform; however, this method is subjective and requires extensive training. Due to this, more objective tests, such as the latency to lie test, have been developed, although more validation of these tests is required. Other identified methods, such as obstacle courses, the rotarod test and kinetic and kinematic approaches, require considerable amounts of equipment, making them impractical for use during on‐farm inspections. Automated methods that rely on movement or activity data have potential for future development but currently lack the resolution of traditional gait scoring and require equipment such as cameras or accelerometers.ConclusionsObjective, seemingly valid, repeatable and feasible options exist for the assessment of walking ability that would facilitate the monitoring of commercial broiler welfare; however, more validation of these methods is required, especially in commercial farm settings.
A Unique Synthetic Route toward a 1,2‐Dihydrodigermene via Formal α‐Elimination of Bromo and Silyl Groups from a Bromo(phenylsilyl)germane
Authors: Uchida Daichi , Yukimoto Mariko , Tokitoh Norihiro , Yamada Hiroko , Mizuhata Yoshiyuki 
Published: August 2024

AbstractA 1,2‐dihydrodigermene bearing Tbb {4‐t‐butyl‐1,3‐bis[bis(trimethylsilyl)methyl]phenyl} groups was successfully synthesized and isolated via formal α‐elimination of bromo and silyl groups from the corresponding Tbb‐substituted boromo(phenylsilyl)germane. This novel synthetic method is conducted under mild conditions, representing a significant advantage in the field concerned. The synthesized 1,2‐dihydrodigermene was characterized by NMR spectroscopy, mass spectrometry, and single‐crystal X‐ray crystallography. In the 1H NMR spectrum, the Ge−H unit was found to be less electronically affected from the substituents compared to that of the previously reported 1,2‐dihydrodigermene. Moreover, the UV/vis spectra at various temperatures indicated the formation of the isomeric (dihydrogermyl)germylene. In fact, the 1,2‐dihydrodigermene once isolated reacted with DMAP in solution to afford the corresponding complex of the (dihydrogermyl)germylene.
Analysis of entropy generation and MHD thermo‐solutal convection flow of Ellis nanofluid through inclined microchannel
Authors: Das Debabrata , Makinde O. D. , Kairi Rishi Raj 
Published: August 2024

AbstractThis study investigates heat, mass transport, and entropy production in Ellis nanofluid flow through an inclined permeable microchannel, considering Navier's slip effects with convective boundary conditions. It incorporates nanoparticle's thermophoresis and Brownian motion effects under a transverse magnetic field, with fluid suction and injection at microchannel walls. Under appropriate physical assumptions, the problem is presented as nonlinear ordinary differential equations, which are later nondimensionalized. The MATLAB bvp4c solver is used for numerical solutions of the transformed equations. Graphical depictions in the study illustrate how various factors influence velocity, temperature, concentration, Bejan number, and entropy generation. Engineering parameters, affected by changes in critical factors, are presented in tabular format, including the skin friction coefficient, Nusselt number, and Sherwood number. Notably, the enhancement in Ellis fluid parameter has a dual effect, enhancing velocity and Bejan number in the microchannel's lower half, while reversing in the upper half. For the increment in Ellis parameter, the impact on Bejan number for 0.5 is significant and the effect on entropy production contrasts with that of Bejan number. This research offers practical insights for designing efficient microfluidic heat exchangers and developing advanced nanofluids for improved thermal performance while minimizing entropy generation. Additionally, it underscores the potential for innovation within the domain of microfluidics and nanomaterial‐driven heat transfer systems. Furthermore, it should be noted that the flow behavior of Ellis nanofluids within microchannels can closely replicate natural flow patterns found in biological systems, offering insights that could have numerous applications in biology and related fields.
Anomalous thresholds in B → (P, V)γ* form factors
Authors: Mutke Simon , Hoferichter Martin , Kubis Bastian 
Published: August 2024

AbstractWe study the effects of anomalous thresholds on the non-local form factors describing the hadronization of the light-quark contribution toB→ (P, V)γ*transitions. Starting from a comprehensive discussion of anomalous thresholds in the triangle loop function for different mass configurations, we detail how the dispersion relation forππintermediate states is affected by contour deformations mandated by the anomalous branch points. Phenomenological estimates of the size of the anomalous contributions to the form factors are provided with couplings determined from measured branching fractions and Dalitz plot distributions. Our key finding is that anomalous effects are suppressed on theρ(770) resonance, while off-peak the effects can become as large as$$ \mathcal{O} $$O(10%) of the full (light-quark-loop induced) non-local form factors. We comment on future generalizations towards higher intermediate states and the charm loop, outlining how the dispersive framework established in this work could help improve the non-local form factors needed as input for a robust interpretation ofB →(P, V)ℓ+ℓ−decays.
Spectra of correlators in the relaxation time approximation of kinetic theory
Authors: Bajec Matej , Grozdanov Sašo , Soloviev Alexander 
Published: August 2024

Abstract
The relaxation time approximation (RTA) of the kinetic Boltzmann equation is likely the simplest window into the microscopic properties of collective real-time transport. Within this framework, we analytically compute all retarded two-point Green’s functions of the energy-momentum tensor and a conserved U(1) current in thermal states with classical massless particles (a ‘CFT’) at non-zero density, and in the absence and presence of broken translational symmetry. This is done in 2 + 1 and 3 + 1 dimensions. RTA allows a full explicit analysis of the analytic structure of different correlators (poles versus branch cuts) and the transport properties that they imply (the thermoelectric conductivities, and the hydrodynamic, quasihydrodynamic and gapped mode dispersion relations). Our inherently weakly coupled analysis thereby also enables a direct comparison with previously known strongly coupled results in holographic CFTs dual to the Einstein-Maxwell-axion theories.
Positivity bounds on electromagnetic properties of media
Authors: Creminelli Paolo , Janssen Oliver , Salehian Borna , Senatore Leonardo 
Published: August 2024

Abstract
We study the constraints imposed on the electromagnetic response of general media by microcausality (commutators of local fields vanish outside the light cone) and positivity of the imaginary parts (the medium can only absorb energy from the external field). The equations of motion for the average electromagnetic field in a medium — the macroscopic Maxwell equations — can be derived from the in-in effective action and the effect of the medium is encoded in the electric and magnetic permeabilities ε(ω, |k|) and μ(ω, |k|). Microcausality implies analyticity of the retarded Green’s functions when the imaginary part of the 4-vector (ω, k) lies in forward light cone. With appropriate assumptions about the behavior of the medium at high frequencies one derives dispersion relations, originally studied by Leontovich. In the case of dielectrics these relations, combined with the positivity of the imaginary parts, imply bounds on the low-energy values of the response, ε(0, 0) and μ(0, 0). In particular the quantities ε(0, 0) – 1 and ε(0, 0) – 1/μ(0, 0) are constrained to be positive and equal to integrals over the imaginary parts of the response. We discuss various improvements of these bounds in the case of non-relativistic media and with additional assumptions about the UV behavior.
Holographic spin alignment of J/ψ meson in magnetized plasma
Authors: Zhao Yan-Qing , Sheng Xin-Li , Li Si-Wen , Hou Defu 
Published: August 2024

Abstract
We study the mass spectra and spin alignment of vector meson J/ψ in a thermal magnetized background using a generalized theoretical framework based on gauge/gravity duality. Utilizing a soft wall model for the QGP background and a massive vector field for the J/ψ meson, we delve into the meson’s spectral function and spin parameters (λθ, λφ, λθφ) for different cases, assessing their response to variations in magnetic field strength, momentum, and temperature. We initially examine scenarios where a meson’s momentum aligns parallel to the magnetic field in helicity frame. Our results reveal a magnetic field-induced positive $$ {\lambda}_{\theta}^{\textrm{H}} $$

λ
θ
H

for low meson momentum, transitioning to negative with increased momentum. As a comparison, we also study the case of momentum perpendicular to the magnetic field and find the direction of magnetic field does not affect the qualitative behavior for the eB-dependence of $$ {\lambda}_{\theta}^{\textrm{H}} $$

λ
θ
H

. Moreover, we apply our model to real heavy-ion collisions for three different spin quantization directions. Further comparisons with experimental data show qualitative agreement for spin parameters λθ and λφ in the helicity and Collins-Soper frames.
Teleparallel Geroch geometry
Authors: Bossard Guillaume , Cederwall Martin , Palmkvist Jakob 
Published: August 2024

Abstract
We construct the teleparallel dynamics for extended geometry where the structure algebra is (an extension of) an untwisted affine Kac-Moody algebra. This provides a geometrisation of the Geroch symmetry appearing on dimensional reduction of a gravitational theory to two dimensions. The formalism is adapted to the underlying tensor hierarchy algebra, and will serve as a stepping stone towards the geometrisation of other infinite-dimensional, e.g. hyperbolic, symmetries.
Holographic fluids from 5D dilaton gravity
Authors: Fichet Sylvain , Megías Eugenio , Quirós Mariano 
Published: August 2024

Abstract
We study a solvable class of five-dimensional dilaton gravity models that continuously interpolate between anti-de Sitter (AdS5), linear dilaton (LD5) and positively curved spacetimes as a function of a continuous parameter ν. The dilaton vacuum expectation value is set by a potential localized on a flat brane. We chart the elementary properties of these backgrounds for any admissible ν, and determine stability conditions of the brane-dilaton system. We find that the spectrum of metric fluctuations can be either continuous or discrete. It features a massless graviton mode confined between the brane and the curvature singularity, and a massive radion mode tied to brane-dilaton stability. We show that, in the presence of a bulk black hole, the holographic theory living on the brane features a perfect fluid. The equation of state of the holographic fluid interpolates between radiation, pressureless matter and vacuum energy as a function of ν. This extends earlier findings on holographic fluids. Our results suggest that the thermodynamics of the fluid mirrors precisely the thermodynamics of the bulk black hole.