bluuebunny/crossref_metadata_2025_split huggingface dataset:
On Hysteresis in a Variable Pitch Fan Transitioning to Reverse Thrust Mode and Back
Authors: Vitlaris Dimitrios , Rajendran David J. , Tunstall Richard , Whurr John , Pachidis Vassilios 
Published: October 2024

Abstract
A novel hysteresis phenomenon during the transition to and back from the reverse thrust mode in a variable pitch fan (VPF) is identified and characterized in this work. This is done using a three-dimensional fully transient unsteady Reynolds-averaged Navier–Stokes (URANS) with the transitioning fan blade airfoils simulated by an adaptation of the mesh displacement method. A “real-time” simulation of the complete VPF hysteresis loop is achieved by specifying a blade wall motion through an Eulerian rotation matrix in differential, gradual steps, and is combined with a mesh probe-and-update routine for improved numerical accuracy and stability. The VPF is modeled to be transitioning in a modern 40000 lbf geared high bypass ratio turbofan engine architecture at “Approach Idle” engine power setting in a typical twin-engine airframe with the flaps, slats, and spoilers set for an aircraft touchdown airspeed of 140 knots. The transition to reverse thrust mode involves flow starvation into the engine, formation of recirculation zones in the bypass duct and the establishment of the reverse stream, all of which occurs in the opposing presence of the freestream flow at aircraft touchdown velocity. The transition back to forward flow mode involves the gradual reestablishment of the freestream, which is opposed by the presence of the reverse stream within the engine. It is quantified that in the transition to reverse thrust, the blockage develops with a larger time delay than the disappearance of the blockage during the transition back due to the interplay of the temporal dynamics of fan blade motion and flow field response. The details of the changes in the flow field behavior, the effect of engine power setting and aircraft touch-down velocity on the hysteresis behavior are explained in detail in the paper. Additional manifestations of the hysteresis phenomena at reverse thrust involving engine spool-up and down, and aircraft acceleration-deceleration maneuvers are also explored. The hysteresis phenomena described in this work are critical in properly developing control schedules to adapt for potential bistable flow field development during the landing run. The study addresses another part of the puzzle in exploring the feasibility of reverse thrust capable VPF engines for future sustainable aircraft to reach aviation climate neutrality.
Comprehensive Experimental Assessment of Unsteady Pressure and Heat Flux in a Small-Core Turbine Over-Tip Shroud
Authors: Sauca Antonio Castillo , Bhatnagar Lakshya , Inhestern Lukas Benjamin , Paniagua Perez Guillermo 
Published: October 2024

Abstract
For novel high-speed small core turbines, with tip clearance below 0.5 mm, even small blade-to-blade tip clearance variation is significant. The assessment of these complex flows is pertinent to the design of the next generation of small-core turbines. This paper provides a thorough experimental analysis of the shroud's unsteady heat flux and static pressure in a small-core squealer-tip blade turbine. Atomic layer thermopile sensors (ALTPs) and fast response pressure transducers were used to perform high-frequency acquisition at 2 MHz around the 51% axial blade chord on the shroud. Measurements were taken at engine-representative conditions at several operational conditions and tip clearances. The signals were phase-locked averaged (PLA) over the revolution period and synchronized to identify individual blade and row signature. The linear relationship between the rotational tip Reynolds and the static pressure ratio across the blade tip reveals the transition point to reverse over-tip flows. Total heat flux is decomposed into the different steady and unsteady heat flux contributions. It is demonstrated that the adiabatic wall temperature governs the unsteady heat flux and contributes to one-third of the total surface heat flux. A linear trend was observed between the unsteady heat flux and the tip clearance measured at the pressure and suction side rims. Similar trends were observed between the local heat flux and the pressure ratio across the tip. A comparison with computational fluid dynamics (CFD) predictions highlights some limitations on resolving the detached and secondary flows, evidencing the necessity of complementary experimental data.
Modeling and Experimental Validation of a Cable-Driven Robot for Three-Dimensional Printing Construction
Authors: Qian Sen , Li Changqi , Zhao Zeyao , Zi Bin 
Published: October 2024

Abstract
Cable-driven robots are characterized by a large workspace, high speed, and load-to-weight ratio, providing a new technology approach for large-scale autonomous 3D construction of lunar surface shelters. A novel deployable cable-driven construction 3D printer (CDCP) is developed in this study. Guiding pulleys are considered and modeled to improve the accuracy of the system. A fuzzy adaptive differential evolution PID (FDEPID) control is proposed to reduce end-effector motion errors in Cartesian space and thus improve printing quality and stability. Concentric and zigzag infill strategies are compared to optimize printing efficiency and infill effectiveness in path planning. The simulations focus on evaluating the effects of pulley kinematics on trajectory tracking, evaluating system dynamics under low-gravity conditions, and examining the effectiveness of motion control and path planning methods. Finally, experiments are carried out to validate the proposed FDEPID control and path planning strategies which demonstrate the great potential of the developed cable-driven printer in the construction of lunar architecture.
Multidisciplinary Optimization of a Mixed-Flow Impeller With 140 Parameters and Its Shapley Additive Explanations
Authors: Xi Guang , Zhang Yong , Ji Cheng , Zhang Chenqing 
Published: October 2024

Abstract
In recent years, we have made several improvements to the geometric parameterization method, the surrogate model method, and the sampling method, with the goal of making the traditional surrogate model-based optimization method applicable to aerodynamic optimization of hundreds of parameters with reasonable computational cost. However, increasing the number of control parameters raises two additional issues. First, the impeller geometry becomes too complex to ensure the required mechanical performance. Second, the optimization mechanism becomes difficult to understand with too many parameters. To address the first issue, this paper builds a multidisciplinary optimization platform to achieve the optimization of a large flow coefficient mixed-flow impeller under 140 control parameters, resulting in a significant improvement in both aerodynamic and mechanical performance. To address the latter, a novel machine learning interpretation tool, Shapley additive explanations (SHAP), is introduced in this paper. Using this methodology, the contribution of all 140 parameter values in the final optimal impeller to each aspect of the performance improvement is presented in this paper, providing the first in-depth understanding of the intricate mechanisms involved in the multidisciplinary optimization of hundreds of control parameters.
Introduction of Axisymmetric Grooves as a Tip Seal Treatment for Small-Core Turbines
Authors: Wiese Connor J. , Berdanier Reid A. , Thole Karen A. 
Published: October 2024

Abstract
The aerodynamic penalties associated with the tip gap flow in axial turbines remain a challenging problem for turbine manufacturers. As modern gas turbines with small-core architectures are brought online, the influence of the tip gap continues to grow. While technologies to reduce the losses associated with the tip gap flow have been implemented into the blades themselves, little attention has been paid to the stationary tip seal, or casing, around the rotor wheel. In this study, an introduction to the use of axisymmetric groove enhancements for the casing of the rotor tip is examined computationally. These studies use the National Experimental Turbine (NExT) geometry, an engine-representative high-pressure turbine blade.
Steady, Reynolds-averaged Navier–Stokes simulations are used to assess the basic characteristics of axisymmetric grooves, such as depth, location, and arrangement. The objective of this introductory study was to determine the feasibility of impacting the tip leakage vortex formation and the associated losses in rotor efficiency. Furthermore, analyses were done with different tip gap heights along with both flat- and squealer-tipped blades. Tip seals with a single groove are demonstrated to improve rotor aerodynamic efficiency relative to ungrooved seals by up to 0.4 points when applied to flat-tipped rotor blades and up to 0.15 points with squealer tips. Alternating arrays of grooves show improvements for flat-tipped blade performance by up to 0.76 points while having a little additional aerodynamic effect on the squealer tip compared to the best single-groove designs. Finally, grooved tip seals appear to exert greater influence on the aerodynamic performance of the turbine rotor when at larger tip gaps, indicating that grooved tip seals alter the sensitivity of rotor performance to the tip gap.
A Dual-Iterative Meshing Stiffness Model and Vibration Analysis for an Angular Misaligned Helical Gear Pair Considering Misalignment-Induced Contact Line Variation
Authors: Wang Liming , Zhang Hao , Duan Lintao , Zou Desheng , Yu Wennian , Xiao Huifang , Chen Zaigang 
Published: October 2024

Abstract
Angular misalignment is a common error in gear transmission systems, significantly altering the contact and dynamic behaviors of the gear system. Conventionally, the time-varying mesh stiffness (TVMS) of helical gear pairs with angular misalignment is estimated under the assumption of a uniform load distribution along a fixed contact line. However, this simplification neglects the variations in contact line length and load distribution due to angular misalignment, thereby compromising the accuracy of TVMS predictions. To address this limitation, we propose a novel dual-iterative model for TVMS calculation in helical gears, accounting for the angular misalignment-induced contact line variation. This model combines traditional iterative calculations for gear slices with an additional iterative loop for the misalignment-induced contact line changes. Furthermore, it considers both axial and tangential meshing stiffnesses. The proposed dual-iterative TVMS model is verified by using the finite element (FE) method. Moreover, a six degree-of-freedom (DOF) dynamic model for misaligned helical gears is established to investigate the effects of misalignments on the vibration characteristics of the gear pair. An experimental setup utilizing a back-to-back helical gear test rig with adjustable angular misalignment is constructed to validate the proposed model. The experimental results exhibit a close alignment with the simulation predictions. It is concluded that the proposed model is suitable for estimating the TVMS and dynamic analysis of helical gear pairs with angular misalignment errors.
Maturity-Associated Longitudinal Variations in Exercise-Induced Acute Hormonal Responses in Adolescent Male Athletes
Authors: Sekine Yuta 
Published: October 2024

Purpose: To examine longitudinal changes in exercise-induced hormonal responses in adolescent male basketball players. Methods: Fifteen adolescent males were assigned to prepeak height velocity (pre-PHV) and post-PHV groups according to the predicted age at PHV. Salivary testosterone, cortisol levels, and the testosterone-to-cortisol ratio were evaluated before (PRE), immediately after (POST), and 15 minutes after a bodyweight resistance training session, which was repeated after 1 year to analyze longitudinal changes in testosterone and cortisol levels. Results: Resting testosterone levels and acute testosterone responses after bodyweight resistance training increased in both groups after 1 year at all measurement points. The POST testosterone levels at initial measurement and PRE and 15-minute postexercise levels at 1 year in the post-PHV group were significantly higher than those in the pre-PHV group. Cortisol levels significantly decreased in the post-PHV group at baseline and 1 year later. In the post-PHV, the testosterone-to-cortisol ratio after bodyweight resistance training was significantly increased at baseline and 1 year later. Conclusions: Although testosterone levels increase with age, no acute response to bodyweight resistance training was observed after 1 year. The change in anabolic status indicated by the testosterone-to-cortisol ratio was due to a decrease in cortisol levels.
Intranasal liposomal angiotensin-(1-7) administration reduces inflammation and viral load in the lungs during SARS-CoV-2 infection in K18-hACE2 transgenic mice
Authors: Mendes Sabrina , Guimarães Lays Cordeiro , Costa Pedro Augusto Carvalho , Fernandez Clara Couto , Figueiredo Maria Marta , Teixeira Mauro Martins , dos Santos Robson Augusto Souza , Guimarães Pedro Pires Goulart , Frézard Frédéric 
Published: October 2024

ABSTRACT

To effectively reduce the health impact of coronavirus disease (COVID-19), it is essential to adopt comprehensive strategies to protect individuals from severe acute respiratory syndrome. In that sense, much effort has been devoted to the discovery and repurposing of effective antiviral and anti-inflammatory molecules. The endogenous peptide angiotensin-(1-7) [Ang-(1-7)] has been recently proposed as a promising anti-inflammatory agent to control respiratory infections. Liposomes also emerged as a safe and effective drug carrier system for local drug delivery to the lungs. In this context, the aim of this study was to develop a liposomal formulation of Ang-(1-7) [LAng (1-7)] and investigate its impact on animal survival as well as its antiviral and anti-inflammatory efficacies after intranasal administration in transgenic K18-hACE2 mice infected with SARS-CoV-2. The liposomal formulation was prepared by the ethanol injection method, exhibiting a mean diameter of 100 nm and a polydispersity index of 0.1. Following treatment of infected mice every 12 hours for 5 days, LAng (1-7) extended animal survival compared to the control groups that received either empty liposomes, free Ang-(1-7), or phosphate-buffered saline. Furthermore, the treatment with LAng (1-7) significantly decreased the viral load, as well as IL-6 and tumor necrosis factor levels in the lungs. Conventional treatment with remdesivir by parenteral route used as a positive control promoted similar effects, leading to improved survival rates and reduced viral load in the lungs without significant effects on IL-6 level. In conclusion, liposomal Ang-(1-7) emerges as a promising formulation to improve the treatment and decrease the severity of respiratory infections, such as COVID-19.
Novel plasmid-mediated CMY variant (CMY-192) conferring ceftazidime-avibactam resistance in multidrug-resistant
Escherichia coli
Authors: Xu Tingting , Wu Weiyuan , Huang Lili , Liu Bin , Zhang Qiaodong , Song Jingjie , Liu Jialong , Li Bing , Li Zhao , Zhou Kai 
Published: October 2024

ABSTRACT

The rapid rise of multidrug resistance (MDR) among Gram-negative bacteria has accelerated the development of novel therapies. Ceftazidime-avibactam (CZA) is a novel β-lactam/β-lactamase inhibitor recently approved for the treatment of limited infectious diseases. Here, we describe a novel CMY variant, CMY-192, that confers high-level resistance to CZA. This gene was detected in a clinical MDR
Escherichia coli
strain (Ec73552) isolated from an outpatient with a community-acquired urinary tract infection who had not received prior CZA treatment. Ec73552 was typed as O101:H9-ST10, a high-risk clone associated with human and animal diseases. Ec73552 was able to colonize the bladder in a mouse model, suggesting that this strain was uropathogenic. CMY-192 shared the highest amino acid identity (98.95%) with CMY-172 and conferred at least a 32-fold increase in CZA MIC (from ≤0.125/4 to 8/4 mg/L) when cloned into a CZA-susceptible
E. coli
DH5α strain. Knockout of CMY-192 in Ec73552 resulted in a 256-fold reduction in CZA MIC (from 64/4 to 0.25/4 mg/L). CMY-192 was encoded on an IncB/O/K/Z-type plasmid (pCMY192). Conjugation assays confirmed that pCMY192 was self-transmissible, resulting in a 256-fold increase in the CZA MIC of the recipient. Notably, pCMY192 cured in Ec73552 did not confer a growth advantage, while the conjugant exhibited reduced biomass and growth rate, indicating that fitness costs imposed by pCMY192 may have been compensated in Ec73552. Our findings highlight the importance of continuous monitoring of CZA susceptibility to prevent the spread of resistance in clinical settings.
Effects of different carbapenemase and siderophore production on cefiderocol susceptibility in
Klebsiella pneumoniae
Authors: Yang Chengcheng , Wang Liang , Lv Jingnan , Wen Yicheng , Gao Qizhao , Qian Feinan , Tian Xiangxiang , Zhu Jie , Zhu Zhichen , Chen Liang , Du Hong 
Published: October 2024

ABSTRACT

The resistance mechanism of Gram-negative bacteria to the siderophore antibiotic cefiderocol is primarily attributed to carbapenemase and siderophore uptake pathways; however, specific factors and their relationships remain to be fully elucidated. Here, we constructed cefiderocol-resistant
Klebsiella pneumoniae
(CRKP) strains carrying different carbapenemases and knocked out siderophore genes to investigate the roles of various carbapenemases and siderophores in the development of cefiderocol resistance. Antimicrobial susceptibility testing revealed that both
bla
NDM
and
bla
KPC
significantly increased the minimum inhibitory concentration (MIC) of
Klebsiella pneumoniae
(KP) to cefiderocol, while
bla
OXA-48
showed a modest increase. Notably, KP expressing NDM exhibited a higher cefiderocol MIC compared to KP expressing KPC, although expression of NDM alone did not induce cefiderocol resistance. Laboratory evolutionary experiments demonstrated that combining pNDM with mutations in the siderophore uptake receptor gene
cirA
and pKPC with a mutation in the two-component system gene
envZ
led to KP reaching a high level of cefiderocol resistance. Although combining pOXA with mutations in the two-component system gene
baeS
did not induce cefiderocol resistance, it significantly reduced susceptibility. Moreover, siderophores could influence the development of cefiderocol resistance. Strains deficient in enterobactin exhibited increased susceptibility to cefiderocol, while deficiencies in yersiniabactin and salmochelin showed no significant alterations. In conclusion, carbapenemase gene expression facilitates cefiderocol resistance, but its presence alone is insufficient. Cefiderocol resistance in CRKP typically involves abnormal expression of certain genes and other factors, such as mutations in siderophore uptake receptor genes and two-component system genes. The enterobactin siderophore synthesis gene
entB
may also contribute to resistance.
Multidrug tolerance conferred by loss-of-function mutations in anti-sigma factor RshA of
Mycobacterium abscessus
Authors: Aragaw Wassihun Wedajo , Gebresilase Tewodros T. , Negatu Dereje A. , Dartois Véronique , Dick Thomas 
Published: October 2024

ABSTRACT

Low-level drug resistance in noncanonical pathways can constitute steppingstones toward acquisition of high-level on-target resistance mutations in the clinic. To capture these intermediate steps in
Mycobacterium abscessus
(Mab), we performed classic mutant selection experiments with moxifloxacin at twofold its minimum inhibitory concentration (MIC) on solid medium. We found that low-level resistance emerged reproducibly as loss-of-function mutations in RshA (MAB_3542c), an anti-sigma factor that negatively regulates activity of SigH, which orchestrates a response to oxidative stress in mycobacteria. Since oxidative stress is generated in response to many antibiotics, we went on to show that deletion of
rshA
confers low to moderate resistance—by measure of MIC—to a dozen agents recommended or evaluated for the treatment of Mab pulmonary infections. Interestingly, this moderate resistance was associated with a wide range of drug tolerance, up to 1,000-fold increased survival of a Δ
rshA
Mab mutant upon exposure to several β-lactams and DNA gyrase inhibitors. Consistent with the putative involvement of the SigH regulon, we showed that addition of the transcription inhibitor rifabutin (RBT) abrogated the high-tolerance phenotype of Δ
rshA
to representatives of the β-lactam and DNA gyrase inhibitor classes. In a survey of 10,000 whole Mab genome sequences, we identified several loss-of-function mutations in
rshA
as well as non-synonymous polymorphisms in two cysteine residues critical for interactions with SigH. Thus, the multidrug multiform resistance phenotype we have uncovered may not only constitute a step toward canonical resistance acquisition during treatment but also contribute directly to treatment failure.
Multigeographic clinical assessment of a molecular diagnostic assay for detection of key codons to predict decreased susceptibility or resistance to cephalosporins in
Neisseria gonorrhoeae
Authors: Wang Liqin , Li Yamei , Xiu Leshan , Hu Lihua , Huang Jia , Yong Gang , Wang Youwei , Cao Wenling , Yang Yang , Wang Feng , Gu Weiming , Peng Junping 
Published: October 2024

ABSTRACT

Cephalosporin resistance in
Neisseria gonorrhoeae
has severely compromised the efficacy of World Health Organization (WHO)-recommended therapies. This study aimed to methodologically evaluate the optimized Six-Codon
Plus
assay, and additionally conducted a multicenter evaluation to assess its clinical application, especially for predicting antimicrobial resistance (AMR). For methodological evaluation, 397 sequence-known
N. gonorrhoeae
isolates were evaluated for specificity, 17 nongonococcal isolates were assessed for cross-reactivity, 159 uncultured urogenital swabs and urine samples were evaluated for sensitivity at the clinical level. For multicenter evaluation, 773 isolates with confirmed phenotypic data and 718 clinical urogenital swabs collected from four geographical cities were, respectively, utilized for the evaluation of AMR-prediction strategies and the clinical application of the assay. The assay accurately identified specific single-nucleotide polymorphisms in resistance-associated genes, the detection limits dropped to 10 copies/reaction for individual targets. The specificity reached 100% and no cross-reactivity occurred with double-target confirmation. The assay could be directly applied to clinical samples containing over 20 copies/reaction. Multicenter evaluation formulated two optimal strategies for decreased susceptibility prediction in specific scenarios, and one tactic for prediction of resistance and identification of FC428-like strains. High sensitivity of 86.84% (95% CI, 71.11–95.05) and specificity of 99.59% (95% CI, 98.71–99.89) for resistance prediction were demonstrated for ceftriaxone (CRO). Regarding
N. gonorrhoeae
identification among multicenter swabs, specificity reached 97.53% (95% CI, 95.49–98.69), and sensitivity reached 93.77% (95% CI, 90.04–96.22). The Six-Codon
Plus
assay exhibited excellent detection performance and formulated optimal AMR-related prediction strategy with regional adaptability, providing critical information for population screening and clinical treatment.