bluuebunny/crossref_metadata_2025_split huggingface dataset:
Explicit Algebraic Reynolds-Stress Modeling of Pressure-Induced Separating Flows in the Presence of Sidewalls
Authors: Mohammed-Taifour Abdelouahab , Weiss Julien , Dufresne Louis 
Published: April 2021

AbstractReynolds-averaged Navier–Stokes (RANS) approach is used to simulate the steady-state of a family of pressure-induced turbulent separation bubbles in the presence of sidewalls. Different turbulence models are employed with a specific emphasis on the baseline explicit algebraic Reynolds stress model (BSL-EARSM) and the simulations are compared with experimental data. The separation and reattachment of a flat-plate turbulent boundary layer are generated through a combination of adverse and favorable pressure gradients (APG-FPG) by numerically reproducing the geometry of the wind-tunnel test section used for the experiments. Three cases are considered a large (LB) and a medium (MB) bubble presenting mean backflow, and a small bubble (SB) without mean-flow reversal. This is achieved by varying the streamwise position of the APG/FPG transition. Good agreement between the BSL-EARSM-computed solutions and the experimental results are obtained for wall-pressure and skin-friction distributions on the centerline plane of the test section as well as for the overall three-dimensional flow topology. However, both detachment and reattachment are predicted too early and the bubble length is slightly overestimated for cases LB and MB. For case LB, the streamwise Reynolds stress is estimated fairly well but its production is somewhat delayed. Normal and shear stresses are in good agreement with the experiments in the upstream part of the bubble but are significantly over-estimated in the reattachment region. The k−ω shear-stress transport (SST) model with the so-called reattachment modification performs better than the other tested linear-eddy-viscosity models but it is still unable to reproduce accurately the three-dimensional flow topology even for the “simplest” case SB. Overall, the results suggest that BSL-EARSM is the most suitable turbulence model for this flow configuration.
Layer-Specific Residual Deformations and Their Variation Along the Human Aorta
Authors: Sokolis Dimitrios P. , Gouskou Nausicaa , Papadodima Stavroula A. , Kourkoulis Stavros K. 
Published: April 2021

Abstract
This study described the regional distribution of layer-specific residual deformations in fifteen human aortas collected during autopsy. Circumferentially and axially cut strips of standardized dimensions from the anterior quadrant of nine consecutive aortic levels were photographed to obtain the zero-stress state for the intact wall. The strips were then dissected into layers that were also photographed to obtain their zero-stress state. Changes in layer-specific opening angle, residual stretches, and thickness at each aortic level and direction were determined via image analysis. The circumferential and axial opening angles of the intima were ∼240 deg and ∼30 deg, respectively, throughout the aorta; those of the adventitia were ∼150 deg and –20 deg to 70 deg. The opening angles of the intact wall and media were similar in either direction. The circumferential residual stretches of the intima and the axial residual stretches of the media showed high values in the aortic arch, decreasing in the descending thoracic aorta and increasing toward the iliac artery bifurcation, while the axial residual stretches of the adventitia increased distally. The remaining residual stretches did not vary significantly with aortic level, suggesting an intimal role in determining circumferential, as well as medial and adventitial roles in determining axial residual stretches. We conclude that the tensile residual stretches released in the intima and media upon separation, and the compressive residual stretches released in the adventitia may moderate the inverse transmural stress gradients under physiologic loads, resulting from the &gt;180 deg circumferential opening angle of the intact wall.
Implementation of Rectangular Vortex Generator Pairs to Improve Film Cooling Effectiveness on Transonic Rotor Blade Endwall
Authors: Li Jinjin , Yan Xin , He Kun , Goldstein Richard J. 
Published: April 2021

Abstract
The rectangular vortex generator pairs (RVGPs) are arranged upstream of the film cooling holes to achieve better coolant coverage on the endwall near the pressure-side corner area. The endwall film cooling effectiveness distributions under transonic flow conditions are numerically calculated for the single RVGP and double rows of RVGPs cases. At first, the effects of three geometrical parameters (i.e., the distance between RVGP and cooling hole, height of RVGP and attack angle of RVGP) on endwall film cooling effectiveness are studied with a single hole and RVGP at different mainstream inlet Reynolds numbers and blowing ratios. Then, the double rows of RVGPs are applied to further enhance the overall film cooling effectiveness on the blade endwall. The results show that the implementation of RVGPs significantly enhances the film cooling effect on transonic blade endwall at a pressure-side corner area. With the increase of RVGP height, the lateral coolant coverage on the endwall corner area is improved. However, by decreasing the distance between the vortex generator pair and cooling hole, the film cooling effectiveness downstream of the cooling holes is increased. The attack angle of RVGP mainly affects the shape of coolant spreading on endwall surface. The RVGP with optimum dimensions and arrangement is able to suppress the coolant from lifting off the endwall and increase the coolant diffusion near the endwall. Compared with no vortex generator case, the area-averaged film cooling effectiveness on endwall with double rows of RVGPs is improved by 13.16%.
Reynolds, Mach, and Freestream Turbulence Effects on the Flow in a Low-Pressure Turbine
Authors: Fiore Maxime , Gourdain Nicolas 
Published: April 2021

Abstract
This article presents the large-eddy simulation (LES) of a low-pressure turbine (LPT) nozzle guide vane (NGV) for different Reynolds (Re) and Mach (Ma) numbers with or without inlet turbulence prescribed. The analysis is based on a slice of an LPT blading representative of a midspan flow, where secondary flows, hub, and shroud effects are lower. The characteristic Re of the LPT can vary by a factor of four between take-off and cruise conditions. In addition, the LPT operates at different Ma values, and the incident flow can have significant levels of turbulence due to upstream blade wakes. This article investigates numerically using LES the flow around an LPT blading with three different Reynolds number Re = 175,000 (cruise), 280,000 (mid-level altitude), and 500,000 (take-off) keeping the same characteristic Mach number Ma = 0.2 and three different Mach number Ma = 0.2, 0.5, and 0.8 keeping the same Reynolds number Re = 280,000. These different simulations are performed with 0% freestream turbulence (FST) followed by inlet turbulence (6% FST). The study focuses on the influence of these three parameters (Re, Ma, and upstream turbulence) on different flow characteristics: pressure distribution around the blade, near-wall flow behavior, loss generation, and turbulent kinetic energy (TKE) budget. The results show an earlier boundary layer separation on the aft region of the blade suction side when the Re is increased, while the increase of the Ma delays separation, similar to freestream turbulence. The TKE budget led on the different cases shows the predominant effect of the turbulent production and diffusion in the wake, the axial evolution of these different terms being relatively insensitive to Re and Ma.
Thermal Post-Buckling Strength Prediction and Improvement of Shape Memory Alloy Bonded Carbon Nanotube-Reinforced Shallow Shell Panel: A Nonlinear Finite Element Micromechanical Approach
Authors: Mehar Kulmani , Mishra Pradeep Kumar , Panda Subrata Kumar 
Published: April 2021

Abstract
This article reported first-time the post-buckling temperature load parameter values of nanotube-reinforced polymeric composite panel and their improvement by introducing the functional material (shape memory alloy, SMA) fiber. The temperature load values of nanotube composite and SMA activation are modeled using the single-layer type higher-order kinematic model in association with isoparametric finite element technique. To ensure the effective properties of SMA bonded nanotube composite under the elevated temperature, a hybrid micromechanical material modeling approach is adopted (Mori–Tanaka scheme and rule of mixture). The present structural geometry distortion under elevated temperature is modeled through the nonlinear strain kinematics (Green–Lagrange), whereas the strain reversal achieved with the help of marching technique (inclusion of material nonlinearity). Owing to the importance of geometrical distortion of the polymeric structure, the current model includes all of the nonlinear strain terms to accomplish the exact deformation. Further, to compute the post-buckling responses, the governing nonlinear eigenvalue equations are derived by Hamilton's principle. The numerical solution accuracy is verified with adequate confirmation of model consistency. The material model applicability for different structural configurations including important individual/combined parameter tested through a series of examples. Moreover, the final understanding relevant to the post-buckling characteristics of the polymeric structure and SMA influences is highlighted in details considering the prestrain, recovery stress, and their volume fractions.
Poor postnatal weight growth is a late finding after sepsis in very preterm infants
Authors: Flannery Dustin D , Jensen Erik A , Tomlinson Lauren A , Yu Yinxi , Ying Gui-Shuang , Binenbaum Gil 
Published: April 2021

ObjectiveTo characterise the association between sepsis and postnatal weight growth when accounting for the degree of growth restriction present at birth.DesignRetrospective matched cohort study using data from the Postnatal Growth and Retinopathy of Prematurity study. Participants were born with birth weights of <1500 g or gestational ages of <32 weeks between 2006 and 2011 at 29 neonatal centres in the USA and Canada. Sepsis was defined as a culture-confirmed bacterial or fungal infection of the blood or cerebrospinal fluid before 36 weeks’ postmenstrual age (PMA). Growth was assessed as the change in weight z-score between birth and 36 weeks’ PMA.ResultsOf 4785 eligible infants, 813 (17%) developed sepsis and 693 (85%) were matched 1:1 to controls. Sepsis was associated with a greater decline in weight z-score (mean difference −0.09, 95% CI −0.14 to −0.03). Postnatal weight growth failure (decline in weight z- score>1) was present in 237 (34%) infants with sepsis and 179 (26%) controls (adjusted OR 1.49, 95% CI 1.12 to 1.97). Longitudinal growth trajectories showed similar initial changes in weight z-scores between infants with and without sepsis. By 3 weeks after sepsis onset, there was a greater decline in weight z-scores relative to birth values in those with sepsis than without sepsis (delta z-score −0.89 vs −0.77; mean difference −0.12, 95% CI −0.18 to −0.05). This significant difference persisted until 36 weeks or discharge.ConclusionInfants with sepsis had similar early weight growth trajectories as infants without sepsis but developed significant deficits in weight that were not apparent until several weeks after the onset of sepsis.
Rationales and uncertainties for aspirin use in COVID-19: a narrative review
Authors: Sayed Ahmed Hazem A , Merrell Eric , Ismail Mansoura , Joudeh Anwar I , Riley Jeffrey B , Shawkat Ahmed , Habeb Hanan , Darling Edward , Goweda Reda A , Shehata Mohamed H , Amin Hossam , Nieman Gary F , Aiash Hani 
Published: April 2021

ObjectivesTo review the pathophysiology of COVID-19 disease, potential aspirin targets on this pathogenesis and the potential role of aspirin in patients with COVID-19.DesignNarrative review.SettingThe online databases PubMed, OVID Medline and Cochrane Library were searched using relevant headlines from 1 January 2016 to 1 January 2021. International guidelines from relevant societies, journals and forums were also assessed for relevance.ParticipantsNot applicable.ResultsA review of the selected literature revealed that clinical deterioration in COVID-19 is attributed to the interplay between endothelial dysfunction, coagulopathy and dysregulated inflammation. Aspirin has anti-inflammatory effects, antiplatelet aggregation, anticoagulant properties as well as pleiotropic effects on endothelial function. During the COVID-19 pandemic, low-dose aspirin is used effectively in secondary prevention of atherosclerotic cardiovascular disease, prevention of venous thromboembolism after total hip or knee replacement, prevention of pre-eclampsia and postdischarge treatment for multisystem inflammatory syndrome in children. Prehospital low-dose aspirin therapy may reduce the risk of intensive care unit admission and mechanical ventilation in hospitalised patients with COVID-19, whereas aspirin association with mortality is still debatable.ConclusionThe authors recommend a low-dose aspirin regimen for primary prevention of arterial thromboembolism in patients aged 40–70 years who are at high atherosclerotic cardiovascular disease risk, or an intermediate risk with a risk-enhancer and have a low risk of bleeding. Aspirin’s protective roles in COVID-19 associated with acute lung injury, vascular thrombosis without previous cardiovascular disease and mortality need further randomised controlled trials to establish causal conclusions.
Reintroduction of elective cardiac interventions in the era of COVID-19: the Barts experience
Authors: Hamshere Stephen , Comer Katrina , Choudhry Fizzah , Rathod Krishna , Mills Gordon , Ferguson Gordon , Lambourne Jonathan , Akhtar Majid , Wragg Andrew , Ozkor Mick , Guttmann Oliver , Mullen Michael , Baumbach Andreas , Smith Elliot , Mathur Anthony , Jones Dan 
Published: April 2021

BackgroundThe response to COVID-19 has required cancellation of all but the most urgent procedures; there is therefore a need for the reintroduction of a safe elective pathway.MethodsThis was a study of a pilot pathway performed at Barts Heart Centre for the admission of patients requiring elective coronary and structural procedures during the COVID-19 pandemic (April–June 2020). All patients on coronary and structural waiting lists were screened for procedural indications, urgency and adverse features for COVID-19 prognosis and discussed at dedicated multidisciplinary teams. Dedicated admission pathways involving preadmission isolation, additional consent, COVID-19 PCR testing and dedicated clean areas were used.Results143 patients (101 coronary and 42 structural) underwent procedures (coronary angiography, percutaneous coronary intervention, transcatheter aortic valve intervention and MitralClip) during the study period. The average age was 68.2; 74% were male; and over 93% had one or more moderate COVID-19 risk factors. All patients were COVID-19 PCR negative on admission with (8.1%) COVID-19 antibody positive (swab negative). All procedures were performed successfully with low rates of procedural complications (9.8%). At 2-week follow-up, no patients had symptoms or confirmed COVID-19 infection with significant improvements in quality if life and symptoms.ConclusionWe demonstrated that patients undergoing coronary and structural procedures can be safely admitted during the COVID-19 pandemic, with no patients contracting COVID-19 during their admission. Reassuringly, patients reflective of typical practice, that is, those at moderate or higher risk, were treated successfully. This pilot provides important information applicable to other settings, specialties and areas to reintroduce services safely.
Circulating Levels of Testosterone, Sex Hormone Binding Globulin and Colorectal Cancer Risk: Observational and Mendelian Randomization Analyses
Authors: Dimou Niki , Mori Nagisa , Harlid Sophia , Harbs Justin , Martin Richard M. , Smith-Byrne Karl , Papadimitriou Nikos , Bishop D. Timothy , Casey Graham , Colorado-Yohar Sandra M. , Cotterchio Michelle , Cross Amanda J. , Marchand Loic Le , Lin Yi , Offit Kenneth , Onland-Moret N. Charlotte , Peters Ulrike , Potter John D. , Rohan Thomas E. , Weiderpass Elisabete , Gunter Marc J. , Murphy Neil 
Published: April 2021

Abstract

Background:
Epidemiologic studies evaluating associations between sex steroid hormones and colorectal cancer risk have yielded inconsistent results. To elucidate the role of circulating levels of testosterone, and sex hormone-binding globulin (SHBG) in colorectal cancer risk, we conducted observational and Mendelian randomization (MR) analyses.

Methods:
The observational analyses included 333,530 participants enrolled in the UK Biobank with testosterone and SHBG measured. HRs and 95% confidence intervals (CI) were estimated using multivariable Cox proportional hazards models. For MR analyses, genetic variants robustly associated with hormone levels were identified and their association with colorectal cancer (42,866 cases/42,752 controls) was examined using two-sample MR.

Results:
In the observational analysis, there was little evidence that circulating levels of total testosterone were associated with colorectal cancer risk; the MR analyses showed a greater risk for women (OR per 1-SD = 1.09; 95% CI, 1.01–1.17), although pleiotropy may have biased this result. Higher SHBG concentrations were associated with greater colorectal cancer risk for women (HR per 1-SD = 1.16; 95% CI, 1.05–1.29), but was unsupported by the MR analysis. There was little evidence of associations between free testosterone and colorectal cancer in observational and MR analyses.

Conclusions:
Circulating concentrations of sex hormones are unlikely to be causally associated with colorectal cancer. Additional experimental studies are required to better understand the possible role of androgens in colorectal cancer development.

Impact:
Our results from large-scale analyses provide little evidence for sex hormone pathways playing a causal role in colorectal cancer development.
See related commentary by Hang and Shen, p. 1302
Association of Oophorectomy and Fat and Lean Body Mass: Evidence from a Population-Based Sample of U.S. Women
Authors: Karia Pritesh S. , Joshu Corinne E. , Visvanathan Kala 
Published: April 2021

Abstract

Background:
Bilateral oophorectomy during a nonmalignant hysterectomy is frequently performed for ovarian cancer prevention in premenopausal women. Oophorectomy before menopause leads to an abrupt decline in ovarian hormones that could adversely affect body composition. We examined the relationship between oophorectomy and whole-body composition.

Methods:
Our study population included cancer-free women 35 to 70 years old from the 1999–2006 National Health and Nutrition Examination Survey, a representative sample of the U.S. population. A total of 4,209 women with dual-energy x-ray absorptiometry scans were identified, including 445 with hysterectomy, 552 with hysterectomy and oophorectomy, and 3,212 with no surgery. Linear regression was used to estimate the difference in total and regional (trunk, arms, and legs) fat and lean body mass by surgery status.

Results:
In multivariable models, hysterectomy with and without oophorectomy was associated with higher total fat mass [mean percent difference (β); βoophorectomy: 1.61%; 95% confidence interval (CI), 1.00–2.28; βhysterectomy: 0.88%; 95% CI, 0.12–1.58] and lower total lean mass [βoophorectomy: −1.48%; 95% CI, −2.67, −1.15; βhysterectomy: −0.87%; 95% CI, −1.50, −0.24) compared with no surgery. Results were stronger in women with a normal body mass index (BMI) and those &lt;45 years at surgery. All body regions were significantly affected for women with oophorectomy, whereas only the trunk was affected for women with hysterectomy alone.

Conclusions:
Hysterectomy with oophorectomy, particularly in young women, may be associated with systemic changes in fat and lean body mass irrespective of BMI.

Impact:
Our results support prospective evaluation of body composition in women undergoing hysterectomy with oophorectomy at a young age.
Sulindac Modulates the Response of Proficient MMR Colorectal Cancer to Anti–PD-L1 Immunotherapy
Authors: Yi Bin , Cheng Hao , Wyczechowska Dorota , Yu Qingzhao , Li Li , Ochoa Augusto C. , Riker Adam I. , Xi Yaguang 
Published: April 2021

Abstract
Immune-checkpoint inhibitor (ICI) therapy has been widely used to treat different human cancers, particularly advanced solid tumors. However, clinical studies have reported that ICI immunotherapy benefits only ∼15% of patients with colorectal cancer, specifically those with tumors characterized by microsatellite instability (MSI), a molecular marker of defective DNA mismatch repair (dMMR). For the majority of patients with colorectal cancer who carry proficient MMR (pMMR), ICIs have shown little clinical benefit. In this study, we examined the efficacy of sulindac to enhance the response of pMMR colorectal cancer to anti–PD-L1 immunotherapy. We utilized a CT26 syngeneic mouse tumor model to compare the inhibitory effects of PD-L1 antibody (Ab), sulindac, and their combination on pMMR colorectal cancer tumor growth. We found that mice treated with combination therapy showed a significant reduction in tumor volume, along with increased infiltration of CD8+ T lymphocytes in the tumor tissues. We also demonstrated that sulindac could downregulate PD-L1 by blocking NF-κB signaling, which in turn led to a decrease in exosomal PD-L1. Notably, PD-L1 Ab can be bound and consumed by exosomal PD-L1 in the blood circulation. Therefore, in combination therapy, sulindac downregulating PD-L1 leads to increased availability of PD-L1 Ab, which potentially improves the overall efficacy of anti–PD-L1 therapy. We also show that low-dose sulindac does not appear to have a systemic inhibitory effect on prostaglandin E2 (PGE2). In conclusion, our findings provide unique insights into the mechanism of action and efficacy for sulindac as an immunomodulatory agent in combination with anti–PD-L1 therapy for the treatment of pMMR colorectal cancer.