bluuebunny/crossref_metadata_2025_split huggingface dataset:
Divergent splanchnic sympathetic efferent nerve pathways regulate interleukin‐10 and tumour necrosis factor‐α responses to endotoxaemia
Authors: McKinley Michael J. , Martelli Davide , Trevizan‐Baú Pedro , McAllen Robin M. 
Published: September 2022

AbstractThe efferent branches of the splanchnic sympathetic nerves that enhance interleukin‐10 (IL‐10) and suppress tumour necrosis factor‐α (TNF) levels in the reflex response to systemic immune challenge were investigated in anaesthetized, ventilated rats. Plasma levels of TNF and IL‐10 were measured 90 min after intravenous lipopolysaccharide (LPS, 60 µg/kg). Splanchnic nerve section, ganglionic blockade with pentolinium tartrate or β2 adrenoreceptor antagonism with ICI 118551 all blocked IL‐10 responses. Restoring plasma adrenaline after splanchnic denervation rescued IL‐10 responses. TNF responses were disinhibited by splanchnic denervation or pentolinium treatment, but not by ICI 118551. Splanchnic nerve branches were cut individually or in combination in vagotomized rats, ruling out any vagal influence on results. Distal splanchnic denervation, sparing the adrenal nerves, disinhibited TNF but did not reduce IL‐10 responses. Selective adrenal denervation depressed IL‐10 but did not disinhibit TNF responses. Selective denervation of either spleen or liver did not affect IL‐10 or TNF responses, but combined splenic and adrenal denervation did so. Finally, combined section of the cervical and lumbar sympathetic nerves did not affect cytokine responses to LPS. Together, these results show that the endogenous anti‐inflammatory reflex is mediated by sympathetic efferent fibres that run in the splanchnic, but not other sympathetic nerves, nor the vagus. Within the splanchnic nerves, divergent pathways control these two cytokine responses: neurally driven adrenaline, acting via β2 adrenoreceptors, regulates IL‐10, while TNF is restrained by sympathetic nerves to abdominal organs including the spleen, where non‐β2 adrenoreceptor mechanisms are dominant.
imageKey points
An endogenous neural reflex, mediated by the splanchnic, but not other sympathetic nerves, moderates the cytokine response to systemic inflammatory challenge. This reflex suppresses the pro‐inflammatory cytokine tumour necrosis factor‐α (TNF), while enhancing levels of the anti‐inflammatory cytokine interleukin‐10 (IL‐10).
The reflex enhancement of IL‐10 depends on the splanchnic nerve supply to the adrenal gland and on β2 adrenoreceptors, consistent with mediation by circulating adrenaline. After splanchnic nerve section it can be rescued by restoring circulating adrenaline.
The reflex suppression of TNF depends on splanchnic nerve branches that innervate abdominal tissues including, but not restricted to, spleen: it is not blocked by adrenal denervation or β2 adrenoreceptor antagonism.
Distinct sympathetic efferent pathways are thus responsible for pro‐ and anti‐inflammatory cytokine components of the reflex regulating inflammation.
Quantification of Autoignition Risk in Aeroderivative Gas Turbine Premixers Using Incompletely Stirred Reactor and Surrogate Modeling
Authors: Iavarone Salvatore , Gkantonas Savvas , Jella Sandeep , Versailles Philippe , Yousefian Sajjad , Monaghan Rory F. D. , Mastorakos Epaminondas , Bourque Gilles 
Published: September 2022

Abstract
The design and operation of premixers for gas turbines must deal with the possibility of relatively rare events causing dangerous autoignition (AI). Rare AI events may occur in the presence of fluctuations of operational parameters, such as temperature and fuel composition, and must be understood and predicted. This work presents a methodology based on incompletely stirred reactor (ISR) and surrogate modeling to increase efficiency and feasibility in premixer design optimization for rare events. For a representative premixer, a space-filling design is used to sample the variability of three influential operational parameters. An ISR is reconstructed and solved in a postprocessing fashion for each sample, leveraging a well-resolved computational fluid dynamics solution of the non-reacting flow inside the premixer. Via detailed chemistry and reduced computational costs, ISR tracks the evolution of AI precursors and temperature conditioned on a mixture fraction. Accurate surrogate models are then trained for selected AI metrics on all ISR samples. The final quantification of the AI probability is achieved by querying the surrogate models via Monte Carlo sampling of the random parameters. The approach is fast and reliable so that user-controllable, independent variables can be optimized to maximize system performance while observing a constraint on the allowable probability of AI.
On the Pneumatic Hammer of Hybrid Gas Bearings: Measurements and Predictions
Authors: Jung Hyunsung , Sin Seki , Kim Kyuman , Heo Junwon , Wee Minsoo , Ryu Keun 
Published: September 2022

Abstract
Hybrid bearings integrating an external pressurizing source are widely used in high-speed turbomachinery due to their notable advantages, including low friction and wear, enhanced reliability and durability, and accurate rotor positioning, as well as large static stiffness and load carry capacity even lubricated with low viscosity liquids. This paper reports experimental data and predictions to identify the characteristics of pneumatic hammer of hybrid gas bearings, 60 mm in diameter, with increasing feed gas pressures. Pneumatic hammer characteristics with static load stiffnesses and flow rates of the test bearing are recorded for increasing static loads with various shaft center positions. A computational program for modeling of hybrid gas bearings predicts static load characteristics of the test bearings. Predictions show a remarkable agreement with measurements. Comparisons of measurements and predictions reveal that calculated reduced damping factors and damping coefficients of hybrid bearings, relying on volume ratio between recess and fluid film, are reliable indicators to estimate the onset condition of pneumatic hammer instability.
Estimation of Resultant Airframe Forces for a Variable Pitch Fan Operating in Reverse Thrust Mode
Authors: Rajendran David John , Tunstall Richard , Pachidis Vassilios 
Published: September 2022

AbstractThe resultant forces with a reverse thrust variable pitch fan (VPF) during the aircraft landing run are computed from the installed reverse thrust flow field obtained from an airframe-engine-VPF research model. The research model features a reverse flow capable VPF design in a future, geared, high-bypass ratio 40,000 lbf engine as installed onto a twin-engine airframe in landing configuration, complete with a rolling ground plane to mimic the runway. The reverse thrust flow field during the aircraft landing run is obtained from the three-dimensional RANS/URANS solutions of the model. The evolution of the installed dynamic reverse thrust flow field is characterized by the interaction of the VPF-induced reverse flow with the freestream. Several flow features like reverse flow wash-down by the freestream, external swirling helical flow development, pylon flow obstruction, 180 deg flow turn into the engine, subsequent separated flows, wake interactions, and multipass recirculating flows are observed. The resultant airframe forces due to the reverse thrust flow field are estimated by adaptations of momentum-based far-field and near-field methods. In the active thrust reverser engagement regime of 140 to 40 knots, the VPF generates a sufficient axial airframe decelerating force in the range of 45% to 8% of maximum takeoff thrust. A drag decomposition study and a notional “blocked-fan” analysis are described to understand the stack-up of the axial decelerating force. Additionally, the resultant force has a landing speed-dependent lateral force component because of the pylon obstruction-induced flow nonuniformity. A beneficial downforce component due to upward deflection of streamlines is also observed. The quantification of the resultant forces from the baseline installed airframe-engine-VPF reverse thrust flow field is a necessary step to explore the feasibility of the VPF reverse thrust system for future efficient turbofan architectures, understand force generation mechanisms, and to identify areas for subsequent design improvement.
An Improved Particle Impact Model by Accounting for Rate of Strain and Stochastic Rebound
Authors: Whitaker Steven M. , Bons Jeffrey P. 
Published: September 2022

Abstract
A methodology for informing physics-based impact and deposition models through the use of novel experimental and analysis techniques is presented. Coefficient of restitution (CoR) data were obtained for Arizona Road Dust (ARD), AFRL02 dust, and each component of AFRL02 impacting a Hastelloy X plate at a variety of flow temperatures (295–866 K), surface temperatures (295–1255 K), particle velocities (0–100 m/s), and impact angles (0–90 deg). High speed particle shadow velocimetry (PSV) allowed individual impact data to be obtained for more than 8 million particles overall, corresponding to 20 combinations of particle composition, flow temperature, and surface temperature. The experimental data were applied to an existing physics-based particle impact model to assess its ability to accurately capture the physics of particle impact dynamics. Using the experimental data and model predictions, two improvements to the model were proposed. The first defined a velocity-dependent “effective yield strength,” designed to account for the effects of strain hardening and strain rate during impact. The second introduces statistical spread to the model output, accounting for the effect of randomizing variables such as particle shape and rotation. Both improvements were demonstrated to improve the model predictions significantly. Applying the improved model to the experimental data sets, along with known temperature-dependent material properties such as the elastic modulus and particle density, allowed the temperature dependence of the effective yield strength to be determined. It was found that the effective yield strength is not a function of temperature over the range studied, suggesting that changes in other properties are responsible for differences in rebound behavior. The improved model was incorporated into a computational simulation of an impinging flow to assess the effect of the model improvements on deposition predictions, with the improved model obtaining deposition trends that more closely match what has been observed in previous experiments. The work performed serves as a stepping stone towards further improvement of physics-based impact and deposition models through refinement of other modeled physical processes.
Profile Loss Reduction of High-Lift Turbine Blades With Rough and Ribbed Surfaces
Authors: Sivaramakrishnan Malathi Ananth , Nardini Massimiliano , Vaid Aditya , Rao Vadlamani Nagabhushana , Sandberg Richard D. 
Published: September 2022

Abstract
Transitional boundary layers on low-pressure turbines (LPTs) are prone to separation on the suction surface of the blade under strong local adverse pressure gradients. Intermittent freestream turbulence, periodic wakes shed by the upstream blades, and surface roughness due to in-service degradation of the blades are shown to suppress the separation. Although this generally leads to a profile loss reduction, some of the benefits are offset by a loss increase associated with an increased turbulent wetted area. In this work, we explore a strategy where the losses in both the transitional and turbulent boundary layers can be reduced. In particular, we employ surface roughness in the transitional regime to reduce the separation bubble-related losses and riblets in the turbulent regime to further reduce the losses due to the turbulent wetted area. The efficacy of this ‘rough-riblet blade surface’ is studied using high-fidelity eddy resolving simulations on the configuration of a flat surface subjected to streamwise varying pressure gradients. Two riblet shapes, sawtooth and scalloped, are considered. When compared to the roughness alone configuration, scalloped riblets reduced the skin friction drag by ≈10% and are much more effective than the sawtooth riblets. Through the streamwise evolution of the boundary layer parameters such as trailing edge momentum thickness, maximum turbulent kinetic energy, and Reynolds stresses, the additional losses incurred at the junction between the smooth wall and riblet leading edge are highlighted.
Effect of Mixing on the Anchoring and Combustion Regimes of Pure Hydrogen Flames in Sequential Combustors
Authors: Solana-Pérez R. , Shcherbanev S. A. , Ciani A. , Noiray N. 
Published: September 2022

Abstract
In this work, we perform an experimental study of the combustion of pure hydrogen in the sequential stage of a generic combustor. This academic test rig is a simplified model of an industrial sequential combustor. The sequential fuel is injected using different injector geometries. The composition and temperature of the hot stream at the inlet of the sequential burner are defined by the mass flows of the hot combustion products from the first stage (30 kW natural gas–air flame with equivalence ratio of 0.7) and of the dilution air. This temperature is varied between 1100 K and 850 K by modifying the dilution air mass flow in order to study the different combustion regimes of the sequential hydrogen flame. High-speed imaging of OH radicals chemiluminescence is performed with optical emission spectroscopy to measure vitiated gas temperatures. In particular, we investigate the transition from a flame anchored in the sequential combustion chamber, to the situation where it stabilizes upstream into the mixing section, when the inlet flow temperature is increased. Of particular interest is the increasing rate of formation of auto-ignition kernels in this transition process. The underlying combustion regime change is analyzed with 0D reactor simulations, and the limitations of such a simplified low-order model of the flame location are discussed. The effects and importance of the mixing process between fresh fuel and the hot vitiated coflow are examined. Two different injectors are compared under the same operating conditions that create different flow structures along the mixing section. As a result of that, they provide different degrees of mixing between the hydrogen and the hot vitiated flow and allow to demonstrate the impact of mixing quality on the flame morphology.
Optimization of Temperature Field by Differentiating Number of Circumferential Control Zones in Local Post Weld Heat Treatment on 9%Cr Heat-Resistant Steel Pipe
Authors: Zhou Fan , Wang Xue , Xu Qiang , Zhang Da 
Published: September 2022

Abstract
This paper reports the optimal use of control zones to achieve required uniformity of temperature distribution in local postweld heat treatment of welds in 9% Cr heat-resistant large pipe system. In this research, local post weld heat treatment tests on temperature distribution with different control zones were carried out on 9%Cr steel pipes (OD 710 mm × 35 mm and OD 575 mm × 35 mm), which was further used for the development of the thermal analysis of the postweld heat treatment model via abaqus. The research results revealed (1) the effect of number of control zone on the uniformity of temperature distribution; (2) the effect of size of pipe diameter on the circumferential temperature and the through-thickness temperature gradients. This article discusses the possible reasons for the temperature difference at various positions of the pipe caused by the air flow inside the pipe with different control zones. Based on the obtained results, a practical method was designed for the selection the number of circumferential control zones on 9%Cr heat-resistant steel pipeline according to the required degree of temperature distribution uniformity. This paper contributes to the specific knowledge and the generic methodology.
Two mental models of integrated care for advanced liver disease: qualitative study of multidisciplinary health professionals
Authors: Arney Jennifer , Gray Caroline , Walling Anne M , Clark Jack A , Smith Donna , Melcher Jennifer , Asch Steven , Kanwal Fasiha , Naik Aanand D 
Published: September 2022

ObjectivesThe purpose of this paper is to present two divergent mental models of integrated advanced liver disease (AdvLD) care among 26 providers who treat patients with AdvLD.Setting3 geographically dispersed United States Veterans Health Administration health systems.Participants26 professionals (20 women and 6 men) participated, including 9 (34.6%) gastroenterology, hepatology, and transplant physicians, 2 (7.7%) physician assistants, 7 (27%) nurses and nurse practitioners, 3 (11.5%) social workers and psychologists, 4 (15.4%) palliative care providers and 1 (3.8%) pharmacist.Main outcome measuresWe conducted qualitative in-depth interviews of providers caring for patients with AdvLD. We used framework analysis to identify two divergent mental models of integrated AdvLD care. These models vary in timing of initiating various constituents of care, philosophy of integration, and supports and resources needed to achieve each model.ResultsClinicians described integrated care as an approach that incorporates elements of curative care, symptom and supportive care, advance care planning and end-of-life services from a multidisciplinary team. Analysis revealed two mental models that varied in how and when these constituents are delivered. One mental model involves sequential transitions between constituents of care, and the second mental model involves synchronous application of the various constituents. Participants described elements of teamwork and coordination supports necessary to achieve integrated AdvLD care. Many discussed the importance of having a multidisciplinary team integrating supportive care, symptom management and palliative care with liver disease care.ConclusionsHealth professionals agree on the constituents of integrated AdvLD care but describe two competing mental models of how these constituents are integrated. Health systems can promote integrated care by assembling multidisciplinary teams, and providing teamwork and coordination supports, and training that facilitates patient-centred AdvLD care.
Clinical features of COVID-19 patients with rebound phenomenon after corticosteroid therapy
Authors: Murakami Koji , Sano Hirohito , Tode Naoki , Tsukita Yoko , Sato Kei , Narita Daisuke , Kimura Nozomu , Matsumoto Shuichiro , Ono Yoshinao , Iwasaki Chikashi , Sugiyama Hatsumi , Suzuki Manami , Kakuto Sho , Konno Shuichi , Kanamori Hajime , Baba Hiroaki , Oshima Kengo , Takei Kentarou , Tokuda Koichi , Tamada Tsutomu , Sugiura Hisatoshi 
Published: September 2022

RationalCorticosteroid therapy plays a key role in the treatment of COVID-19 patients with respiratory failure. However, a rebound phenomenon after steroid cessation rarely occurs. Here, we investigated the clinical features of patients with rebound after steroid therapy.MethodsIn total, 84 patients with COVID-19 treated with corticosteroids were enrolled and analysed retrospectively. A rebound was defined as when a patient’s respiratory status deteriorated after the cessation of corticosteroid therapy, without secondary bacterial infection.ResultsSubjects in the rebound group were more likely to having severe respiratory failure than those in the non-rebound group. While the duration of steroid therapy was longer in the rebound group (8 days vs 10 days, p=0.0009), the dosage of steroid and the timing of the start or termination of steroid therapy did not show any differences between the two groups (p=0.17 and 0.68, respectively). The values of soluble interleukin-2 receptor (sIL-2R) at the baseline and the values of C reactive protein (CRP) or lactate dehydrogenase (LDH) at the end of steroid therapy were significantly higher in the rebound group (937 vs 1336 U/mL; p=0.002, 0.63 vs 3.96 mg/dL; p=0.01 and 278 vs 451 IU/mL; p=0.01, respectively). No patient in the rebound group suffered from thromboses, and the causes of death were exacerbation of COVID-19, ventilator-associated pneumonia or sepsis. The prediction model using baseline features for the rebound phenomenon included four variables of age >68 years, required supplemental oxygen >5 L/min, lymphocyte counts <792 /µL and sIL-2R >1146 U/mL. The discrimination ability of this model was 0.906 (0.755–0.968).ConclusionThese findings suggest that severe respiratory failure has a higher risk for the rebound phenomenon after the cessation of corticosteroids, and the values of sIL-2R, LDH and CRP are useful to assess the probability of developing rebound. A multivariate model was developed to predict rebound risk, which showed acceptable discrimination ability.
Erythrocyte complement receptor 1 (ECR1) and erythrocyte-bound C4d (EC4d) in the prediction of poor pregnancy outcomes in systemic lupus erythematosus (SLE)
Authors: Conklin John , Golpanian Michael , Engel Alexis , Izmirly Peter , Belmont H Michael , Dervieux Thierry , Buyon Jill P , Alexander Roberta Vezza 
Published: September 2022

BackgroundComplement activation has been associated with adverse pregnancy outcomes (APO) in SLE. Pregnant women with SLE were studied to evaluate whether complement dysregulation within the first two pregnancy trimesters predicts APO.MethodsPregnant women fulfilled classification criteria for SLE. APO included neonatal death, preterm delivery before 36 weeks and small for gestational age newborn. Pre-eclampsia was also evaluated. Erythrocyte complement receptor 1 (ECR1) and erythrocyte-bound C4d (EC4d) were measured by flow cytometry. Complement proteins C3 and C4 were measured by immunoturbidimetry and anti-double-stranded DNA by ELISA in serum. Statistical analysis consisted of t-test, confusion matrix-derived diagnostic analysis, and multivariate logistic regression.ResultsFifty-one women had 57 pregnancies and 169 visits during the study. Baseline visits occurred mainly in the first (n=32) and second trimester (n=21). Fourteen (24.6%) pregnancies resulted in 21 APO with preterm delivery being the most common (n=10). ECR1 <5.5 net mean fluorescence intensity in the first trimester predicted APO with a diagnostic OR (DOR) of 18.33 (95% CI: 2.39 to 140.4; t-test p=0.04). Other individual biomarkers did not reach statistical significance. To estimate the likelihood of APO, we developed an algorithm that included the week of pregnancy, ECR1 and EC4d. From this algorithm, a Pregnancy Adversity Index (PAI) was calculated, and a PAI >0 indicated an elevated likelihood of pregnancy complications (DOR: 20.0 (95% CI: 3.64 to 109.97)).ConclusionsLow levels of ECR1 in early or mid-pregnancy are predictive of an APO. Incorporating the weeks of gestation and both ECR1 and EC4d generated a PAI, which further predicted serious pregnancy complications.