bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vivo Evaluation of the Anti-Schistosomal Potential of Ginger-Loaded Chitosan Nanoparticles on Schistosoma mansoni: Histopathological, Ultrastructural, and Immunological Changes
Authors: El-Derbawy Mona M. , Salem Hala S. , Raboo Mona , Baiuomy Ibrahim R. , Fadil Sana A. , Fadil Haifa A. , Ibrahim Sabrin R. M. , El Kholy Walaa A.
Published: November 2022

Chemotherapy is the most widely advocated method of Schistosome control. However, repeated chemotherapy leads to the emergence of drug-resistant Schistosoma strains. Therefore, efforts to find alternative drugs, especially those of natural origin, have risen globally. Nanoparticles (NPs) have received special interest as efficient drug delivery systems. This work aimed to investigate the anti-schistosomal potential of Zingiber officinale (ginger, Zingiberaceae)-loaded chitosan nanoparticles (GCsNPs) on Schistosoma mansoni experimentally infected mice that were exposed to 80 ± 10 cercariae/mouse. The study groups are: (G1) negative control; (G2) positive control; (G3) praziquantel in a dose of 500 mg/kg/day for two consecutive days; (G4) ginger in a dose of 500 mg/kg treated; (G5) chitosan nanoparticles in a dose 3 mg/kg (G6) GCsNPs in a dose 250 mg/kg; and (G7) GCsNPs in a dose 500 mg/kg. The anti-schistosome potential was assessed using histopathological scanning electron microscopically and immunological parameters. The results showed that there was a significant decrease in cellular granuloma count (p < 0.05) and granuloma diameter (p < 0.001) in all infected treated mice groups, in comparison to the infected non-treated group with the highest reduction in both G3 and G7. SEM of S. mansoni adult worm recovered from G3 showed mild edema of oral and ventral suckers with some peeling and blebs around them, while that recovered from G7 showed abnormal oedematous oral and retracted ventral sucker, edema of the tegument, rupture of many tubercles with vacuolation and complete loss of spines. All infected treated mice groups, in comparison to positive control G2, showed a significant reduction in IL-4, IL-10, and TNF-α levels (p-value < 0.001), especially groups G6 and G7 (p-value < 0.05); both G6 and G7 values were nearer to the normal that indicated recovery of the liver tissue.
Acute Ischemic Stroke with Devastating Consequences Can Occur Due to Posterior Sternoclavicular Joint Dislocation
Authors: Ghazaleh Dana , Salari Apameh , Mohl Leighton , Janssen Madisen , Brown Kevin , Ghannam Malik
Published: November 2022

Posterior sternoclavicular joint dislocation is a rare injury requiring prompt diagnosis as it has been associated with the compression of the subclavian and brachiocephalic arteries. We report the case of a 27-year-old male presenting with altered mental status and left hemiparesis found to have life-altering neurologic damage caused by severe orthopedic injury after a fall while intoxicated. Imaging revealed a posteriorly displaced right medial clavicle with surrounding hematoma compressing the brachiocephalic artery causing local thrombus formation and distal embolization, ultimately resulting in malignant cerebral infarction. His hospital course was complicated by cerebral edema requiring decompressive craniectomy, hemorrhagic transformations, brachiocephalic pseudoaneurysm, and the development of remote embolic ischemic infarctions.
Accommodation Response Variations in University Students under High Demand for Near-Vision Activity
Authors: De-Hita-Cantalejo Concepción , Benítez-Rodríguez María-de-los-Ángeles , Sánchez-González María Carmen , Bautista-Llamas María-José , Sánchez-González José-María
Published: November 2022

The objective of this study was to investigate accommodation changes and visual discomfort in a university student population after a period of high demand for near-vision activity. A total of 50 university students aged between 20 and 22 years were recruited. The tests performed involved positive relative accommodation (PRA), negative relative accommodation (NRA), accommodation amplitude (AA), and monocular and binocular accommodative facility (MAF and BAF). Visual discomfort was measured on a scale involving a visual discomfort questionnaire (VDQ). All accommodative variables underwent changes during the exam period; specifically, regarding NRA and PRA, 30.4% and 15.1% of the studied population, respectively, appeared to be below average. Moreover, 42.3% of the population exhibited values below average in the second measure of AA. On the other hand, a small percentage of the population was below average in MAF and BAF measurements: 3% in the monocular right eye test, 6% in the left eye test, and 9.1% in the binocular facility test. Finally, the VDQ score did not reveal a statistically significant difference between the two measurements. Prolonged near-distance work, such as a university exams period, changed all accommodation systems (amplitude of accommodation, relative accommodation, and accommodation facility). These changes influence an accommodation excess that results in blurred vision, headache, and problems with focusing.
Mitochondria-Targeted Human Catalase in the Mouse Longevity MCAT Model Mitigates Head-Tilt Bedrest-Induced Neuro-Inflammation in the Hippocampus
Authors: Rubinstein Linda , Kiffer Frederico , Puukila Stephanie , Lowe Moniece G. , Goo Brie , Luthens Amalia , Schreurs Ann-Sofie , Torres Samantha M. , Steczina Sonette , Tahimic Candice G. T. , Allen Antiño R.
Published: November 2022

Microgravity (modeled by head-tilt bedrest and hind-limb unloading), experienced during prolonged spaceflight, results in neurological consequences, central nervous system (CNS) dysfunction, and potentially impairment during the performance of critical tasks. Similar pathologies are observed in bedrest, sedentary lifestyle, and muscle disuse on Earth. In our previous study, we saw that head-tilt bedrest together with social isolation upregulated the milieu of pro-inflammatory cytokines in the hippocampus and plasma. These changes were mitigated in a MCAT mouse model overexpressing human catalase in the mitochondria, pointing out the importance of ROS signaling in this stress response. Here, we used a head-tilt model in socially housed mice to tease out the effects of head-tilt bedrest without isolation. In order to find the underlying molecular mechanisms that provoked the cytokine response, we measured CD68, an indicator of microglial activation in the hippocampus, as well as changes in normal in-cage behavior. We hypothesized that hindlimb unloading (HU) will elicit microglial hippocampal activations, which will be mitigated in the MCAT ROS-quenching mice model. Indeed, we saw an elevation of the activated microglia CD68 marker following HU in the hippocampus, and this pathology was mitigated in MCAT mice. Additionally, we identified cytokines in the hippocampus, which had significant positive correlations with CD68 and negative correlations with exploratory behaviors, indicating a link between neuroinflammation and behavioral consequences. Unveiling a correlation between molecular and behavioral changes could reveal a biomarker indicative of these responses and could also result in a potential target for the treatment and prevention of cognitive changes following long space missions and/or muscle disuse on Earth.
2-((3-(4-Methoxyphenyl)-4,5-dihydroisoxazol-5-yl)methyl)benzo[d]isothiazol-3(2H)-one1,1-dioxide
Authors: El Mahmoudi Ayoub , Chkirate Karim , Tachallait Hamza , Van Meervelt Luc , Bougrin Khalid
Published: November 2022

In this work, a novel compound N-(3-(4-methoxyphenyl)isoxazolin-5-yl)methylsaccharin has been synthesized. The molecular structure of the compound was determined using various spectroscopic techniques and confirmed by a single-crystal X-ray diffraction analysis. In the single crystal, C–H…O hydrogen bonds between neighboring molecules form chains along the a-axis direction. Hirshfeld surface analysis indicates that the most important contributions to the crystal packing are from H…H (35.7%), H…O/O…H (33.7%), and H…C/C…H (13%) interactions. The optimized structure calculated using density functional theory at the B3LYP/6–311 G(d,p) level is compared with the experimentally determined structure in the solid state. The calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy gap is 4.9266 eV.
Influence of the Composition on the Compressive Behaviour of a Semi-Metallic Brake-Pad Material
Authors: Serrano-Munoz Itziar , Magnier Vincent , Brunel Florent , Dufrenoy Philippe
Published: November 2022

The contact interface between the rotation and static part of a friction brake is central to the optimal functioning of the brake system due to the occurrence of heat dissipation, mechanical interaction and thermal exchanges. Generally, braking performances are evaluated by the energetic efficiency and wear rates of the contact surface. However, the compressive behaviour of the contact materials has also a significant contribution to the overall performances. In this work, the meso- and microscopic compressive behaviour of a sintered semi-metallic brake-pad material is investigated mainly via compression testing coupled with Digital Image Correlation (DIC) technique, as well as optical and scanning electron microscopy (SEM) analysis. The composition of a reference material (RM) is simplified to a selection of nine components, as opposed to up to thirty components typically used in commercial brake-pad materials. The retained components are considered as the most crucial for safe-operating performances. At the studied stress levels, the RM material is flexible (E = 5330 MPa), deformable (Ezz-plastic = −0.21%), and exhibits hysteresis loops. Subsequently, the contribution to the mechanical response of each individual component is investigated by producing the so-called dissociated materials, where the number of components is, at a time, further reduced. It is observed that the macroscopic behaviour is mainly controlled by the content (i.e., size distribution, shape and nature) of graphite particles, and that the hysteresis is only related to one of the two types of graphite used (G2 particles). Moreover, RM containing 13 wt% of G2 particles embedded in a relatively soft matrix (10.86 GPa) is able to increase the hysteresis (by 35%) when compared to the dissociated material containing 20 wt% of G2 particles which is embedded in a stiffer matrix (E = 106 GPa).
Stress-Induced Grain Refinement in Hard Magnetic Mn52Al45.7C2.3 Fabricated Using the Ball-Milling Method
Authors: Attyabi Seyed Nourallah , Radmanesh Seyed Mohammad Ali , Seyyed Ebrahimi Seyyed Ali , Dehghan Hossein , Lalegani Zahra , Hamawandi Bejan
Published: November 2022

Mn52Al45.7C2.3 flakes with different sizes were prepared with two distinct surfactant-assisted ball-milling methods using cylindrical and barrel containers. Different microstructure and magnetic properties were measured based on the sequence of the container shape and different ball-milling times (2, 5, and 10 h). Morphology investigations showed that for powders milled in a barrel container, the amount of τ-phase was more compared to the samples milled in a cylindrical container. Moreover, in the powders milled with barrel containers, considerably higher magnetic properties were obtained in terms of saturation magnetization (Ms) and remanent magnetization (Mr) compared to those powders milled with cylindrical containers. Magnetic properties were found to be a function of the ball-milling time. High remanent magnetization and saturation magnetization have been found for powders milled in barrel containers, whereas only mediocre remanent magnetization and saturation magnetization have been measured in the case of milling in cylindrical containers. The highest Ms = 52.49 emu g−1 and Mr = 24.10 emu g−1 were obtained for the powders milled in barrel containers for 2 h. The higher magnetic properties taken from the milling in barrel containers is due to the higher shear stress and more uniform strain distribution induced by the barrel configuration, resulting in the stable τ-phase at a reasonably low-strain microstructure.
Hyperbranched Polymer Network Based on Electrostatic Interaction for Anodes in Lithium-Ion Batteries
Authors: Yang Chenchen , Jiang Yan , Cheng Na , Zhao Jianwei , Chen Feng
Published: November 2022

Silicon is considered as one of the ideal anode materials for the new generation of lithium-ion batteries due to its extremely high theoretical specific capacity. Nevertheless, in the actual charging and discharging process, the Si electrode will lose its electrochemical performance due to the huge volume change of Si nanoparticles resulting in detachment from the surface of the fluid collector. The polymer binder can bond the Si nanoparticles together in a three-dimensional cross-linking network, which can thus effectively prevent the Si nanoparticles from falling off the surface of the fluid collector due to the drastic change of volume during the charging and discharging process. Therefore, this study developed a new polymer binder based on electrostatic interaction with hyperbranched polyethylenimine (HPEI) as the main body and water-soluble carboxylated polyethylene glycol (CPEG) as the cross-linker, where the degree of cross-linking can be easily optimized by adjusting the pH value. The results demonstrate that, when the density of positive and negative charges in the binder is relatively balanced at pH 7, the stability of the battery’s charge–discharge cycle is significantly improved. After 200 cycles of constant current charge–discharge test, the specific capacity retention rate is 63.3%.
Effect of Geometrical Parameters of Microscale Particles on Particle-Stimulated Nucleation and Recrystallization Texture of Al-Si-Mg-Cu-Based Alloy Sheets
Authors: Jeon Jonggyu , Lee Sangjun , Kyeong Joonseok , Shin Seeun , Kang Heon
Published: November 2022

The effects of the shapes (needle and round) and volume fractions (low and high) of microscale particles in Al-Si-Mg-Cu-based alloys on recrystallization behavior, texture evolution, mechanical properties, and formability are investigated. The recrystallized grain size decreases as the size and volume fraction of the particles decrease and increase, respectively, regardless of the particle shape. The investigated alloys with a relatively low volume fraction of 0.7 to 2.4 vol.% exhibit higher efficiency particle-stimulated nucleation (PSN) than alloys with a high volume fraction of 6.0 to 21.0 vol.%. This is because the interaction between the particles and dislocations cannot be greatly promoted when the volume fraction of the particles is large enough to form agglomerates. The sheets with round-shaped particles exhibit higher yield strength (YS) and elongation (EL) than sheets with needle-shaped particles. The improvement in YS is due to the combined effects of grain refinement and particle strengthening, and the EL is improved by reducing the probability of cracking at the tips of round-shaped particles. The sheets with round-shaped particles exhibit relatively higher average plastic strain ratio (r¯) and planar anisotropy (∆r) than the sheets with needle-shaped particles, owing to the development of Goss {110}<001> or rotated-Goss {110}<110> orientations.
Low Cycle Fatigue Behavior of Plastically Pre-Strained HSLA S355MC and S460MC Steels
Authors: Prosgolitis Christos G. , Kermanidis Alexis T. , Kamoutsi Helen , Haidemenopoulos Gregory N.
Published: November 2022

Cold roll forming used in the manufacturing of lightweight steel profiles for racking storage systems is associated with localized, non-uniform plastic deformations in the corner sections of the profiles, which act as fatigue damage initiation sites. In order to obtain a clearer insight on the role of existing plastic deformation on material fatigue performance, the effect of plastic pre-straining on the low cycle fatigue behavior of S355MC and S460MC steels was investigated. The steels were plastically deformed at different pre-strain levels under tension, and subsequently subjected to cyclic strain-controlled testing. Plastic pre-straining was found to increase cyclic yield strength, decrease ductility, and induce cyclic softening, which, in S460MC, degrades fatigue resistance compared to the unstrained material. In unstrained conditions, the materials present a cyclic softening to hardening transition with increasing plastic strain amplitude, which in S355MC occurs at lower strain amplitudes and degrades its fatigue resistance with regard to the pre-strained material. Pre-straining also leads to a reduction in transition life from low to high cycle fatigue. SEM fractography, performed following the onset of crack initiation, revealed that plastic pre-straining reduces the fatigue fracture section as well as striation spacing, predominantly in the S355MC steel.
A Novel Dual-Emission Fluorescence Probe Based on CDs and Eu3+ Functionalized UiO-66-(COOH)2 Hybrid for Visual Monitoring of Cu2+
Authors: Che Jie , Jiang Xin , Fan Yangchun , Li Mingfeng , Zhang Xuejuan , Gao Daojiang , Ning Zhanglei , Li Hongda
Published: November 2022

In this work, CDs@Eu-UiO-66(COOH)2 (denoted as CDs-F2), a fluorescent material made up of carbon dots (CDs) and a Eu3+ functionalized metal–organic framework, has been designed and prepared via a post-synthetic modification method. The synthesized CDs-F2 presents dual emissions at 410 nm and 615 nm, which can effectively avoid environmental interference. CDs-F2 exhibits outstanding selectivity, great sensitivity, and good anti-interference for ratiometric sensing Cu2+ in water. The linear range is 0–200 µM and the limit of detection is 0.409 µM. Interestingly, the CDs-F2’s silicon plate achieves rapid and selective detection of Cu2+. The change in fluorescence color can be observed by the naked eye. These results reveal that the CDs-F2 hybrid can be employed as a simple, rapid, and sensitive fluorescent probe to detect Cu2+. Moreover, the possible sensing mechanism of this dual-emission fluorescent probe is discussed in detail.
Research on Process Planning Method of Aerospace Engine Bolt Tightening Based on Digital Twin
Authors: Wang Yuanyu , Liu Yong , Wang Junyi , Zhang Jiachuan , Zhu Xiaojun , Xu Zhigang
Published: November 2022

Aerospace engine is the source of power for the development of national defense and aerospace. Engine bolt tightening is an important part of the aerospace engine production process. At present, most of the bolt tightening methods of aerospace engines are manual tightening or traditional rigid tightening, which lead to the problem of low efficiency and large engine deformation. This paper proposes a process planning method for bolt tightening of aerospace engine based on digital twin, including flexible tightening mechanism design, tightening sequence optimization, the establishment of the digital twin system of the tightening mechanism, etc. The flexible tightening mechanism is suitable for different types of aerospace engines. Based on bolt tightening sequence optimization, the deformation and stress of the cabin section during the tightening process are reduced. The bolt tightening work is completed in the digital twin system, the real-time communication of physical and digital space synchronizes the operations of them. After tightening, the residual pre-tightening force of bolts are detected based on the ultrasonic method. The results show that the proposed method can solve the problems of low efficiency of aerospace engine bolt tightening and the problem of the cabin’s large deformation. Furthermore, it provides technical reference and theoretical basis for the bolt tightening technology of aerospace engine.
Learning by Watching via Keypoint Extraction and Imitation Learning
Authors: Sun Yin-Tung Albert , Lin Hsin-Chang , Wu Po-Yen , Huang Jung-Tang
Published: November 2022

In recent years, the use of reinforcement learning and imitation learning to complete robot control tasks have become more popular. Demonstration and learning by experts have always been the goal of researchers. However, the lack of action data has been a significant limitation to learning by human demonstration. We propose an architecture based on a new 3D keypoint tracking model and generative adversarial imitation learning to learn from expert demonstrations. We used 3D keypoint tracking to make up for the lack of action data in simple images and then used image-to-image conversion to convert human hand demonstrations into robot images, which enabled subsequent generative adversarial imitation learning to learn smoothly. The estimation time of the 3D keypoint tracking model and the calculation time of the subsequent optimization algorithm was 30 ms. The coordinate errors of the model projected to the real 3D key point under correct detection were all within 1.8 cm. The tracking of key points did not require any sensors on the body; the operator did not need vision-related knowledge to correct the accuracy of the camera. By merely setting up a generic depth camera to track the mapping changes of key points after behavior clone training, the robot could learn human tasks by watching, including picking and placing an object and pouring water. We used pybullet to build an experimental environment to confirm our concept of the simplest behavioral cloning imitation to attest the success of the learning. The effectiveness of the proposed method was accomplished by a satisfactory performance requiring a sample efficiency of 20 sets for pick and place and 30 sets for pouring water.
Energy-Absorbing and Eco-Friendly Perspectives for Cork and WKSF Based Composites under Drop-Weight Impact Machine
Authors: Sheikhi Mohammad Rauf , Gürgen Selim , Altuntas Onder
Published: November 2022

Lightweight structures with high energy absorption capacity are in high demand for energy absorption applications in a variety of engineering fields, such as aerospace, automotive, and marine engineering. Anti-impact composites are made of energy-absorbing materials that are incorporated into structures to protect the occupant or sensitive components against strikes or falls. This study deals with an experimental investigation of multi-layer composites consisting of cork and warp-knitted spacer fabrics (WKSF) for anti-impact applications. Composites were designed and created with a laser cutting machine in eight different configurations. To measure the energy absorption of the manufactured composite samples, a low-velocity drop-tower machine was designed, and the maximum reaction force due to the strike of the impactor on the specimens was measured by a dynamometer located under the samples. Moreover, energy absorption and specific energy absorption capacities were calculated for each specimen. In the final part of this study, the Life Cycle Assessment (LCA) of the designed composites was calculated to understand the eco-friendly properties of the composites.
Characteristics Analysis and Optimization of the Structural Parameters of PTRB
Authors: Zheng Shicheng , Fu Yongling , Wang Deyi , Pan Junlin , Liu Ziyu , Chen Juan
Published: November 2022

Bearings, as integral parts and components in machinery and equipment, play a critical role in system performance. In this paper, the theoretical models of basic axial load rating, basic radial load rating, and friction torque for the planetary thread roller bearing (PTRB) were derived. Then, a detailed comparison was made between the performance indexes of a PTRB prototype and common high-quality bearing products to demonstrate the advantages of PTRB in volume, bearing capacity, and use method. Next, the effects of different structural parameters on the performance indexes of PTRB were analyzed. On this basis, a multi-objective optimization design was carried out on PTRB under axial load and radial load separately with basic load rating and friction torque as optimization objects to obtain PTRB with superior comprehensive performance. Designers could, in consideration of their specific needs and optimized design results, select the structural parameters of PTRB. Furthermore, a dedicated performance test system was researched and developed, which verified the good static bearing capacity and impact resistance of the PTRB prototype. Within the range of dynamic load rating, the test data were slightly larger than the simulation data for the friction torque, manifesting a relatively high degree of precision of the theoretical model.
Personalized Image Aesthetics Assessment via Multi-Attribute Interactive Reasoning
Authors: Zhu Hancheng , Zhou Yong , Shao Zhiwen , Du Wenliang , Wang Guangcheng , Li Qiaoyue
Published: November 2022

Due to the subjective nature of people’s aesthetic experiences with respect to images, personalized image aesthetics assessment (PIAA), which can simulate the aesthetic experiences of individual users to estimate images, has received extensive attention from researchers in the computational intelligence and computer vision communities. Existing PIAA models are usually built on prior knowledge that directly learns the generic aesthetic results of images from most people or the personalized aesthetic results of images from a large number of individuals. However, the learned prior knowledge ignores the mutual influence of the multiple attributes of images and users in their personalized aesthetic experiences. To this end, this paper proposes a personalized image aesthetics assessment method via multi-attribute interactive reasoning. Different from existing PIAA models, the multi-attribute interaction constructed from both images and users is used as more effective prior knowledge. First, we designed a generic aesthetics extraction module from the perspective of images to obtain the aesthetic score distribution and multiple objective attributes of images rated by most users. Then, we propose a multi-attribute interactive reasoning network from the perspective of users. By interacting multiple subjective attributes of users with multiple objective attributes of images, we fused the obtained multi-attribute interactive features and aesthetic score distribution to predict personalized aesthetic scores. Experimental results on multiple PIAA datasets demonstrated our method outperformed state-of-the-art PIAA methods.
Testing of an Adaptive Algorithm for Estimating the Parameters of a Synchronous Generator Based on the Approximation of Electrical State Time Series
Authors: Senyuk Mihail , Beryozkina Svetlana , Berdin Alexander , Moiseichenkov Alexander , Safaraliev Murodbek , Zicmane Inga
Published: November 2022

The results of testing the algorithms of the adaptive model of a synchronous generator using theoretical and real physical data are presented in this study. The adaptive model of a synchronous machine is an equations system, which describes both the static and transient operation of a generator. Parameters of the adaptive model are found using measurements of a generator’s operational parameters. The single-machine model was created in Matlab/Simulink software to test the theoretical data. This single-machine model consists of a synchronous generator, a step-up transformer, and a transmission line. The test model also includes models of the automatic voltage regulator and steam turbine governor. The real electrodynamic model was used to verify the adaptive model of a synchronous machine. It consisted of four synchronous generators, with values of power capacity of 5 kW and 15 kW. The data logger with a sampling rate of 57.8 kHz was developed and installed to measure the operating parameters of each generator. As a result of testing on both models, the following values were estimated: inertia moment, d-axis and q-axis reactance, and load angle. These values were compared with the reference values. The adaptive model of a synchronous machine can be used in systems of emergency control and assessment of generator state.
Increasing Micro-Rotational Viscosity Results in Large Micro-Rotations: A Study Based on Monolithic Eulerian Cosserat Fluid–Structure Interaction Formulation
Authors: Hajano Nazim Hussain , Khan Muhammad Sabeel , Liu Lisheng
Published: November 2022

In classical continuum mechanics, a monolithic Eulerian formulation is used for numerically solving fluid–structure interaction (FSI) problems in the frame of a physically deformed configuration. This numerical approach is well adapted to large-displacement fluid–structure configurations where velocities of solids and fluids are computed all at once in a single variational equation. In the recent past, a monolithic Eulerian formulation for solving FSI problems of finite deformation to study the different physical features of fluid flow has been employed. Almost all the current studies use a classical framework in their approach. Despite producing decent results, such methods still need to be appropriately configured to generate exceptional results. Recently, a number of researchers have used a non-classical framework in their approach to analyze several physical problems. Therefore, in this paper, a monolithic Eulerian formulation is employed for solving FSI problems in a non-classical framework to study the micro-structural characteristics of fluid flow by validating the results with classical benchmark solutions present in the literature. In this respect, the Cosserat theory of continuum is considered where a continuum of oriented rigid particles has, in addition to the three translational degrees of freedom of classical continuum, three micro-rotational degrees of freedom. The mathematical formulation of model equations is derived from the general laws of continuum mechanics. Based on the variational formulation of the FSI system, we propose the finite element method and semi-implicit scheme for discretizing space and time domains. The results are obtained by computing a well-known classical FSI benchmark test problem FLUSTRUK-FSI-3* with FreeFem++. The results of the study indicate that the increase in micro-rotational viscosity μr leads to significantly large micro-rotations in fluid flow at the micro-structural level. Further, it is found that the amplitude of oscillations is related inversely to the material parameters c1 and μr while the increase in c1 stabilizes the amplitude of oscillations relatively more quickly than increasing μr. The color snapshots of the numerical results at different times during the computer simulations and general conclusions drawn from the results are presented.
Parameter Estimation for a Fractional Black–Scholes Model with Jumps from Discrete Time Observations
Authors: Thony John-Fritz , Vaillant Jean
Published: November 2022

We consider a stochastic differential equation (SDE) governed by a fractional Brownian motion (BtH) and a Poisson process (Nt) associated with a stochastic process (At) such that: dXt=μXtdt+σXtdBtH+AtXt−dNt,X0=x0>0. The solution of this SDE is analyzed and properties of its trajectories are presented. Estimators of the model parameters are proposed when the observations are carried out in discrete time. Some convergence properties of these estimators are provided according to conditions concerning the value of the Hurst index and the nonequidistance of the observation dates.
Cooperative Purchasing with General Discount: A Game Theoretical Approach
Authors: García-Martínez Jose A. , Meca Ana , Vergara G. Alexander
Published: November 2022

In some situations, sellers of certain commodities usually provide price discounts for large orders according to a decreasing unit price function. Buyers of such commodities can cooperate and form purchasing groups to benefit from these price discounts. A natural way to allocate the corresponding cost reductions is the equal price rule. We analyze this situation as a cooperative game. We show that when the decreasing unit price function is linear, the equal price rule coincides with the Shapley value and the nucleolus of the cooperative game. However, some buyers may argue that the equal price rule is not acceptable because it favors those who buy just a few units of the product. This can be more problematic when the decreasing unit price function is nonlinear: In that case, the equal price rule loses some of its good properties and it no longer matches the Shapley value or the nucleolus. Unlike the linear case, in this nonlinear case, the Shapley value and nucleolus do not assign the same price to all agents, so there are different price rules. However, they have a computability problem, as both are very laborious to calculate for a large number of agents. To find a suitable alternative, we first study the properties that a different price rule should have in this situation. Second, we propose a family of different price rules that hold those properties and are easy to calculate for a large number of agents. This family of different price rules provides buyers (companies, institutions, consumers, etc.) with an easy-to-implement method which ensures stability in cooperative purchasing.
Earthquake Catastrophe Bond Pricing Using Extreme Value Theory: A Mini-Review Approach
Authors: Anggraeni Wulan , Supian Sudradjat , Sukono  , Halim Nurfadhlina Binti Abdul
Published: November 2022

Earthquake catastrophe bond pricing models (ECBPMs) employ extreme value theory (EVT) to predict severe losses, although studies on EVT’s use in ECBPMs are still rare. Therefore, this study aimed to use a mini-review approach (MRA) to examine the use of EVT and identify the gaps and weaknesses in the methods or models developed. The MRA stages include planning, search and selection, analysis, and interpretation of the results. The selection results showed five articles regarding the application of EVT in ECBPMs. Furthermore, the analysis found the following: First, the generalized extreme value (GEV) could eliminate extreme data in a period. Second, the trigger model using two parameters is better than one, but the study did not discuss the joint distribution of the two parameters. Third, the autoregressive integrated moving average (ARIMA) allows negative values. Fourth, Cox–Ingersoll–Ross (CIR) in-coupon modeling is less effective in depicting the real picture. This is because it has a constant volatility assumption and cannot describe jumps due to monetary policy. Based on these limitations, it is hoped that future studies can develop an ECBPM that reduces the moral hazard.
Adaptive Neural Backstepping Control Approach for Tracker Design of Wheelchair Upper-Limb Exoskeleton Robot System
Authors: Aly Ayman A. , Hsia Kuo-Hsien , El-Sousy Fayez F. M. , Mobayen Saleh , Alotaibi Ahmed , Mousa Ghassan , Le Dac-Nhuong
Published: November 2022

In this study, the desired tracking control of the upper-limb exoskeleton robot system under model uncertainty and external disturbance is investigated. For this reason, an adaptive neural network using a backstepping control strategy is designed. The difference between the actual values of the upper-limb exoskeleton robot system and the desired values is considered as the tracking error. Afterward, the auxiliary variable based on the tracking error is defined and the virtual control input is obtained. Then, by using the backstepping control procedure and Lyapunov stability concept, the convergence of the position tracking error is proved. Moreover, for the compensation of the model uncertainty and the external disturbance that exist in the upper-limb exoskeleton robot system, an adaptive neural-network procedure is adopted. Furthermore, for the estimation of the unknown coefficient related to the parameters of the neural network, the adaptive law is designed. Finally, the simulation results are prepared for demonstration of the effectiveness of the suggested method on the upper-limb exoskeleton robot system.
Managerial Delegation and Conflicting Interest in Unionized Duopoly with Firm Heterogeneity
Authors: Chen Shih-Shen , Ko Po-Sheng , Tsai Chien-Shu , Lee Jen-Yao
Published: November 2022

This paper utilized a three-stage dynamic game to analyze the conflicts of interest between stakeholders caused by firm heterogeneity. We show that the higher the degree of heterogeneity, the higher the sales delegation incentive given. The firm’s heterogeneity scale will cause industry profit, union utility, consumer surplus and manager bonus conflicts of interest. Furthermore, the intensity of conflict is lower between the industry and the union than between the industry and consumer and between the industry and manager if the degree of heterogeneity is relatively small.
Can Ultrasound-Guided Femoral Vein Measurements Predict Spinal Anesthesia-Induced Hypotension in Non-Obstetric Surgery? A Prospective Observational Study
Authors: Yılmaz Ayşe , Demir Ufuk , Taşkın Öztürk , Soylu Veysel Garani , Doğanay Zahide
Published: November 2022

Background and objectives: To investigate whether ultrasound (US)-guided femoral vein (FV) and inferior vena cava (IVC) measurements obtained before spinal anesthesia (SA) can be utilized to predict SA-induced hypotension (SAIH) and to identify risk factors associated with SAIH in patients undergoing non-obstetric surgery under SA. Methods: This was a prospective observational study conducted between November 2021 and April 2022. The study included 95 patients over the age of 18 with an American Society of Anesthesiologists (ASA) physical status score of 1 or 2. The maximum and minimum diameters of FV and IVC were measured under US guidance before SA initiation, and the collapsibility index values of FV and IVC were calculated. Patients with and without SAIH were compared. Results: SAIH was observed in 12 patients (12.6%). Patients with and without SAIH were similar in terms of age [58 (IQR: 19–70) vs. 48 (IQR: 21–71; p = 0.081) and sex (males comprised 63.9% of the SAIH and 75.0% of the non-SAIH groups) (p = 0.533). According to univariate analysis, no significant relationship was found between SAIH and any of the FV or IVC measurements. Multiple logistic regression analysis revealed that having an ASA class of 2 was the only independent risk factor for SAIH development (p = 0.014), after adjusting for age, sex, and all other relevant parameters. Conclusions: There is not enough evidence to accept the feasibility of utilizing US-guided FV or IVC measurements to screen for SAIH development in patients undergoing non-obstetric surgery under SA. For this, multicenter studies with more participants are needed.
The Relevance of GIRK Channels in Heart Function
Authors: Campos-Ríos Ana , Rueda-Ruzafa Lola , Lamas José Antonio
Published: November 2022

Among the large number of potassium-channel families implicated in the control of neuronal excitability, G-protein-gated inwardly rectifying potassium channels (GIRK/Kir3) have been found to be a main factor in heart control. These channels are activated following the modulation of G-protein-coupled receptors and, although they have been implicated in different neurological diseases in both human and animal studies of the central nervous system, the therapeutic potential of different subtypes of these channel families in cardiac conditions has remained untapped. As they have emerged as a promising potential tool to treat a variety of conditions that disrupt neuronal homeostasis, many studies have started to focus on these channels as mediators of cardiac dynamics, thus leading to research into their implication in cardiovascular conditions. Our aim is to review the latest advances in GIRK modulation in the heart and their role in the cardiovascular system.
High-Entropy Perovskites Pr1−xSrx(Cr,Mn,Fe,Co,Ni)O3−δ (x = 0–0.5): Synthesis and Oxygen Permeation Properties
Authors: Zhao Zhijun , Rehder Lena , Steinbach Frank , Feldhoff Armin
Published: November 2022

High-entropy perovskite oxides have already been studied in various fields owing to their high-entropy-induced properties. Partial substitution of an element by a lower valence element usually improves the oxygen permeability of perovskite oxides, but high substitution amounts may lead to structural instability. In this work, pure high-entropy perovskites Pr1−xSrx(Cr,Mn,Fe,Co,Ni)O3−δ with high amounts Sr up to x=0.5 were synthesized via a sol–gel method. Several characterization methods prove that the solubility of Sr increases with higher temperatures of the heating treatment. The ceramic with x=0.5 shows a transition from semi-conductive to metallic behavior when the temperature reaches 873 K. Its oxygen flux is comparable to the low-entropy counterpart La0.6Sr0.4Co0.5Fe0.5O3−δ. A stable run of ca. 46.2 h was documented for oxygen permeation under an air/CO2 gradient.
Designing Workplace Training for Generational Differences: Does It Matter?
Authors: Berge Zane L.
Published: November 2022

There is little to no empirical evidence that designing instruction to match individual learning styles increases learning. Similarly, the same is true when people are grouped into “generations”. If generational differences exist, the size of their effect is small and does not affect the effectiveness of training. Still, educators and trainers overwhelmingly think differentiated design based on learning styles and generational differences cause students to learn more. Why? I argue that there are other outcomes to instruction besides effectiveness. If instruction matches an individual’s preferences, content and skills can often be learned more efficiently and certainly appeal more to the learner than if it does not match their preferences. It is argued that both efficiency and appeal of instruction are important outcomes for students even when effectiveness is not significantly changed by matching the instructional approach to the learner’s preferences.
Effect of Ho Substitution on Magnetic Properties and Microstructure of Nanocrystalline Nd-Pr-Fe-B Alloys
Authors: Xiao Caihai , Zeng Weiwei , Tang Yongli , Lu Cifu , Tang Renheng , Zheng Zhigang , Liao Xuefeng , Zhou Qing
Published: November 2022

The inevitable thermal demagnetization of magnets at high-temperatures is a key issue for Nd-Fe-B based permanent magnetic materials, especially for electric motors. Here, we report the effect of partially substituting the element Holmium (Ho) on the magnetic properties and microstructure of nanocrystalline melt-spun [(NdPr)1−xHox]14.3Fe76.9B5.9M2.9 (x = 0–0.6; M = Co, Cu, Al and Ga) alloys. It shows that Ho can enter into the main phase and significantly enhance the coercivity (Hcj). A large coercivity of 23.9 kOe is achieved in the x = 0.3 alloy, and the remanent magnetization (Mr) remains in balance. The abnormal elevated temperature behavior of Mr is observed in the alloys with a high amount of Ho substitution, in which the Mr of the x = 0.6 alloy increases with rising temperature from 300 K to 375 K owing to the antiparallel coupling between Ho and Fe moments. As a result, the positive value (0.050%/K) of temperature coefficient α of Mr is achieved in the x = 0.6 alloy within the temperature range of 300–400 K, in excess of that of existing Nd-Fe-B magnets. The temperature coefficient β of Hcj is also improved by Ho substitution, indicating the introduction of Ho in Nd-Fe-B magnets is beneficial for thermal stability. The microstructure observation of x = 0, 0.3 and 0.6 alloys confirmed the grain refinement by Ho substitution, and Ho prefers to remain in the 2:14:1 phase than Nd and Pr. The present finding provides an important reference for the efficient improvement of the thermal stability of Nd-Fe-B-type materials.
Numerical Analysis of Mixing Performance in an Electroosmotic Micromixer with Cosine Channel Walls
Authors: Chen Zhong , Wang Yalin , Zhou Song
Published: November 2022

Micromixers have significant potential in the field of chemical synthesis and biological pharmaceuticals, etc. In this study, the design and numerical simulations of a passive micromixer and a novel active electroosmotic micromixer by assembling electrode pairs were both presented with a cosine channel wall. The finite element method (FEM) coupled with Multiphysics modeling was used. To propose an efficient micromixer structure, firstly, different geometrical parameters such as amplitude-to-wavelength ratio (a/c) and mixing units (N) in the steady state without an electric field were investigated. This paper aims to seek a high-quality mixing solution. Therefore, based on the optimization of the above parameters of the passive micromixer, a new type of electroosmotic micromixer with an AC electric field was proposed. The results show that the vortices generated by electroosmosis can effectively induce fluid mixing. The effects of key parameters such as the Reynolds number, the number of electrode pairs, phase shift, voltage, and electrode frequency on the mixing performance were specifically discussed through numerical analysis. The mixing efficiency of the electroosmotic micromixer is quantitatively analyzed, which can be achieved at 96%. The proposed micromixer has a simple structure that can obtain a fast response and high mixing index.
Is There a Universal Endurance Microbiota?
Authors: Olbricht Hope , Twadell Kaitlyn , Sandel Brody , Stephens Craig , Whittall Justen B.
Published: November 2022

Billions of microbes sculpt the gut ecosystem, affecting physiology. Since endurance athletes’ performance is often physiology-limited, understanding the composition and interactions within athletes’ gut microbiota could improve performance. Individual studies describe differences in the relative abundance of bacterial taxa in endurance athletes, suggesting the existence of an “endurance microbiota”, yet the taxa identified are mostly non-overlapping. To narrow down the source of this variation, we created a bioinformatics workflow and reanalyzed fecal microbiota from four 16S rRNA gene sequence datasets associated with endurance athletes and controls, examining diversity, relative abundance, correlations, and association networks. There were no significant differences in alpha diversity among all datasets and only one out of four datasets showed a significant overall difference in bacterial community abundance. When bacteria were examined individually, there were no genera with significantly different relative abundance in all four datasets. Two genera were significantly different in two datasets (Veillonella and Romboutsia). No changes in correlated abundances were consistent across datasets. A power analysis using the variance in relative abundance detected in each dataset indicated that much larger sample sizes will be necessary to detect a modest difference in relative abundance especially given the multitude of covariates. Our analysis confirms several challenges when comparing microbiota in general, and indicates that microbes consistently or universally associated with human endurance remain elusive.
Comparative Evaluation of Luminex xTAG® Gastrointestinal Pathogen Panel and Direct-From-Stool Real-Time PCR for Detection of C. difficile Toxin tcdB in Stool Samples from a Pediatric Population
Authors: Tyrrell Hannah , Morin Sarah B. N. , Lloyd Colin D. , Parsons Brendon , Stokowski Taryn , Xie Jianling , Zhuo Ran , Lee Bonita E. , Pang Xiao-Li , Freedman Stephen B. , Chui Linda
Published: November 2022

Detection of Clostridioides difficile toxins in patients with gastroenteritis has increasingly been accomplished through the use of enteric multiplex syndromic panels. Comparisons of the performance of these panels to both direct-from-stool (DFS) and culture-enriched stools followed by polymerase chain reaction (PCR) methods in pediatric populations are limited. Here, we compare the performance of the Luminex xTAG® Gastrointestinal Pathogen Panel (GPP) to our DFS in-house real-time PCR (DFS RT-PCR) assay for the detection of C. difficile toxin gene, tcdB, using 2641 stool specimens collected from children enrolled in the Alberta Provincial Pediatric EnTeric Infection Team (APPETITE) study in Alberta, Canada. We used culture enrichment followed by in-house RT-PCR to resolve discordant results between the two assays. We found excellent agreement (k = 0.89) between the GPP and our DFS RT-PCR assay: the positive percent agreement between the two assays was 97%, and the negative percent agreement was 99%. GPP, a multi-analyte platform can easily be implemented into a routine diagnostic laboratory for detecting enteric pathogens including C. difficile.