bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulation prediction of pressure distribution of guide vanes in a high-head pump turbine
Authors: He Lei , Gao Zhongxin , Chen Ying , Zhang Jianguang , Ma Bingquan , Meng Xiaochao , Rao Lei 
Published: June 2021

Abstract
In order to clarify the influence of different turbulence models on the numerical simulation of the pump turbine, 3D numerical steady simulations using four kinds of turbulence models: SST, k-ε, k-ω and RNG k-ε were applied to simulate the flow inside the mixed-flow pump turbine. 16 monitoring points were installed in guide vanes to obtain the relationship between pressure distribution of guide vanes in different monitoring locations and operation conditions. The pressure distribution of guide vanes was simulated using four kinds of turbulence models, and compared with the model test results. The results show that when the turbulence model is SST, the numerical simulation results are closer to the model test results.
Opening sequence optimization for La Coche pumps back-to-back start-up through electrically coupled Pelton unit.
Authors: Andolfatto Loïc , Rentschler Martin , Haeussler Walter , Gervais Nicolas 
Published: June 2021

Abstract
La Coche pumped storage power plant features 4 pump-turbine units and a Pelton unit, with the possibility for direct full frequency electrical coupling of the Pelton unit generator with the pump turbine motors. The back-to-back start-up mode consists in reaching synchronous speed of both pump unit and turbine unit by using the hydraulic power delivered to the turbine, without requiring absorbed electrical power peak usually perturbing the grid during pump start-up.
The fastest start-up is achieved while the hydraulic power injected in the system is maximized. The associated risk lies in reaching levels of mechanical load of the Pelton runner that dramatically reduce the runner remaining lifetime at each start-up.
The proposed work focus on the Pelton turbine nozzle opening law optimization to minimize the start-up time, while keeping the level of stress in the Pelton runner below a maximum allowed value. Numerical simulations coupling CFD and FEM were associated to train a surrogate model predicting the runner condition along the transient start-up sequence. Resolution of the first order differential equation of the coupled units start-up trajectory under boundary conditions defined from nozzle opening sequence allowed to assess both associated start-up time and stress levels.
Results of the field measurement gathered during the commissioning phase were compared to simulation results to update the implemented model parameters and optimize the start-up sequence allowing fast and long lasting back-to-back start-up capacity.
CFD simulation of the pump trip runaway transient process of a pumped-storage power plant with head 700 m
Authors: Yang Z Y , Zhang X X , Liu D M , Cheng Y G , Zhao M D 
Published: June 2021

Abstract
Simulating transient processes of pumped-storage power plants is essential for the design and optimization of pump-turbine and water conveyance system. Because pressure pulsations and runner forces cannot be obtained from the traditional 1D transient simulation methods, 3D CFD simulations are necessary. In this study, the fast runaway transient process, occurring after the pump trip of a pumped-storage plant with a head of 700m, was simulated by using the CFD method that couples the 1D water conveyance system and 3D turbine. The phenomena, composed of water hammer fluctuations, pressure pulsation transitions, and flow pattern evolutions, were described and analyzed. We found that the flow patterns and pressure pulsations change violently as the working point goes through different regions. Especially, the pressure pulsations and unbalanced radial runner forces are the most severe in the S-shaped characteristic region. The strong impact on blades, large scale recirculating vortices in blade passages, obvious rotating stalls in vane and blade regions, transitional backflows at runner inlet and outlet, and strong circumferential velocity in vaneless space are the main sources. The dynamic working trajectory does not follow the measured static characteristic curve and demonstrates an undamped loop in the S-shaped region. This paper provides some evidence on the relations between flow structure and pressure pulsation features, although the mechanism of dynamic characteristics needs further investigations.
Evolution of discharge and runner rotation speed along no-load curves of Francis turbines
Authors: Fortin M , Nennemann B , Deschênes C , Houde S 
Published: June 2021

Abstract
In hydraulic turbines, no-load operation is among the most damaging conditions since unextracted swirl leads to the creation of highly energetic flow structures causing high pressure and strain fluctuations on the turbine components. To date, experimental and numerical studies typically focus on flow characteristics for a specific no-load condition of a specific turbine. However, for a given turbine, a unique no-load condition exists for every single guide vane opening, forming what is called a no-load curve. Few studies describe the evolution of engineering quantities such as discharge and speed along the no-load curve even if those quantities may highlight trends in no-load behavior that can be used to tailor numerical simulations according to specific flow conditions. This paper presents results from a project underway at Andritz Hydro Canada Inc., in collaboration with Université Laval, to analyze the extensive database of experimental no-load tests performed at model scale in order to identify the evolution of discharge and runner rotation speed following the guide vane opening.
Reimagining educational equity through strategic alliance partnerships in response to the USA STEM-M diversity gap
Authors: Rocha Janet , Castillo-Lavergne Claudia M , Byrd Marcus J , Carnethon Mercedes R , Miller Rebecca , Lin Maria , Marsh Erica E , Jackson Janice K , Yancy Clyde W 
Published: June 2021

SummaryAddressing the USA diversity gap in science, technology, engineering, mathematics and medicine (STEM-M) through strategic alliance partnerships (SAPs) is an innovative solution toward combating the educational inequalities presented in K-12 education for marginalized youth interested in STEM-M professions. We present a model that unites multiple stakeholder s committed to diversifying the workforce in STEM-M, through the implementation of a multi-year high school pipeline program designed to better achieve STEM-M equity, access and opportunity at the secondary school level. We developed a unique model based on an SAP in a large metropolitan area in the Midwest that joins an Academic Medical Center and a local Public High School. Our results involving 46 students over 8 years demonstrate 100% high school graduation rates; 97% college attendance with full or partial scholarship support, and early evidence of post-graduation aspirations in STEM-M careers. Our early progress calls for more rigorous study against standard educational practices. If our program is proven to be more effective, then potentially more strategic public−private partnerships to foster K-12 pipeline programs to better achieve equity through educational access, opportunities and resources should be developed and targeted for those marginalized youth that have been historically denied STEM-M opportunities. After 10 years of dedicated effort, we see evidence of potential benefits of this SAP to develop K-12 pipeline programs with similar aims of STEM-M diversification, particularly by way of more-equitable provision of educational opportunities to students belonging to minority racial and ethnic groups.
IL-23RVariant rs11805303 Is Associated With Susceptibility to the Development of Cutaneous Leishmaniasis inLeishmania guyanensis–Infected Individuals
Authors: Santos da Silva Lener , Santo Júnior José do Espírito , de Mesquita Tirza Gabrielle Ramos , Santos Veronica Alice Marinho , de Souza Josué Lacerda , de Araújo Felipe Jules , da Silveira Júnior Cláudio Marcello , da Silva Cilana Chagas , Queiroz Krys Layane Guimarães Duarte , Sequera Héctor David Graterol , Guerra Marcus Vinitius de Farias , de Souza Mara Lúcia Gomes , Ramasawmy Rajendranath 
Published: June 2021

AbstractBackgroundEmerging evidence suggests that the interleukin (IL) 17/ IL-23 axis may play a role in the pathogenesis of leishmaniasis. Our aim was to investigate whether the IL-23R variant rs11805303 is a risk factor for the development of cutaneous leishmaniasis (CL) in Leishmania guyanensis–infected individuals.MethodsWe genotyped by polymerase chain reaction–restriction fragment length polymorphism the rs11805303 C/T in 828 patients with CL and 806 healthy individuals. Plasma tumor necrosis factor–α, IL-6, interferon-γ, IL-1β, and IL-17 were measured with the Bioplex assay.ResultsThe distribution of the genotypes differed between patients with CL and healthy controls with a common odds ratio of 1.78 (P = 2.2 × 10–11) for the disease-associated T allele. Leishmania guyanensis–infected individuals homozygous for the T allele show a 200% increased risk of progressing to disease development, with a 95% confidence interval ranging from 81% to 400% (P = 9.9 × 10–6) in comparison to individuals homozygous for the C allele. Males homozygous for the T allele have higher plasma levels of IL-17 compared with heterozygous or homozygous CC individuals.ConclusionsThe present association of the IL-23R variant rs11805303 with the development of CL suggests that the IL-17/IL-23 axis may play an important role in the pathogenesis of CL.
Genetic Evidence for a Potential Environmental Pathway to Spillover Infection of Rat-Borne Leptospirosis
Authors: Casanovas-Massana Arnau , de Oliveira Daiana , Schneider Andrew G , Begon Mike , Childs James E , Costa Federico , Reis Mitermayer G , Ko Albert I , Wunder Elsio A 
Published: June 2021

Abstract
In this study, we genotyped samples from environmental reservoirs (surface water and soil), colonized rat specimens, and cases of human severe leptospirosis from an endemic urban slum in Brazil, to determine the molecular epidemiology of pathogenic Leptospira and identify pathways of leptospirosis infection. We identified a well-established population of Leptospira interrogans serovar Copenhageni common to human leptospirosis cases, and animal and environmental reservoirs. This finding provides genetic evidence for a potential environmental spillover pathway for rat-borne leptospirosis through the environment in this urban community and highlights the importance of environmental and social interventions to reduce spillover infections.
Assessing the impact of clinical pharmacy services on the healthcare outcomes of patients attending an outpatient haemodialysis unit in a rural hospital in Egypt: a quasi-experimental study
Authors: Nagib Reem , Abdul-Latif Maha , Sakoury Hoda S , Elrggal Mahmoud E , Cheema Ejaz , Elnaem Mohamed Hassan , El-Fass Karim A 
Published: June 2021

Abstract

Objectives
This study aimed to investigate the impact of newly introduced clinical pharmacy services on the health care of chronic haemodialysis patients attending an outpatient haemodialysis unit in a rural hospital with limited resources in Alexandria, Egypt.

Methods
A quasi-experimental pre-/post-test study was conducted from November 2016 till June 2018. Clinical pharmacists collected relevant information using a pre-specified form. Patients’ data were reviewed for drug-related problems (DRPs), which were documented using the Pharmaceutical Care Network Europe (PCNE) classification system, version 8.02 and resolved by the clinical pharmacists. Measured values of calcium, phosphorus and haemoglobin were compared with target levels set by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Proportions of patients achieving therapeutic values of each parameter were compared before and after implementing the program using the McNemar test. We also reported the analysis of DRPs identified and addressed by the clinical pharmacy team.

Key findings
A total of 685 DRPs were identified during the follow-up period. Improper dose and inappropriate drug selection were the most common DRPs (45.8% and 18.9%, respectively). There was a statistically significant increase in the proportion of patients achieving target corrected calcium levels (30% pre-intervention versus 69.6% post-intervention, P = 0.001) and haemoglobin levels (9.1% pre-intervention versus 31.9% post-intervention, P = 0.003), but not in phosphorus levels (18.6% pre-intervention versus 22% post-intervention, P = 0.7).

Conclusions
Clinical pharmacists were able to resolve frequent DRPs and improve some markers of health care in haemodialysis patients.
The role of atmospheric outflows in the migration of hot Jupiters
Authors: Kurbatov E P , Bisikalo D V 
Published: June 2021

ABSTRACT
Many of observed hot Jupiters are subject to atmospheric outflows. Numerical simulations have shown that the matter escaping from the atmosphere can accumulate outside the orbit of the planet, forming a torus. In a few 108 yr, the mass of the torus can become large enough to exert a significant gravitational effect on the planet. Accumulation of mass, in its own turn, is hindered by the activity of the star, which leads to the photoevaporation of the torus matter. We explore the role of these and other factors in the planet’s migration in the epoch when the protoplanetary disc has already disappeared. Using HD 209458 system as an example, we show that the gravitational interaction with the torus leads to the possibility of migration of the planet to its observable position, starting from an orbit ≳0.3 au.
Peculiar velocity estimation from kinetic SZ effect using deep neural networks
Authors: Wang Yuyu , Ramachandra Nesar , Salazar-Canizales Edgar M , Feldman Hume A , Watkins Richard , Dolag Klaus 
Published: June 2021

ABSTRACT
The Sunyaev–Zel’dolvich (SZ) effect is expected to be instrumental in measuring velocities of distant clusters in near future telescope surveys. We simplify the calculation of peculiar velocities of galaxy clusters using deep learning frameworks trained on numerical simulations to avoid the independent estimation of the optical depth. Images of distorted photon backgrounds are generated for idealized observations using one of the largest cosmological hydrodynamical simulations, the Magneticum simulations. The model is tested to determine its ability of estimating peculiar velocities from future kinetic SZ observations under different noise conditions. The deep learning algorithm displays robustness in estimating peculiar velocities from kinetic SZ effect by an improvement in accuracy of about 17 per cent compared to the analytical approach.
Does jackknife scale really matter for accurate large-scale structure covariances?
Authors: Favole Ginevra , Granett Benjamin R , Silva Lafaurie Javier , Sapone Domenico 
Published: June 2021

ABSTRACT
The jackknife method gives an internal covariance estimate for large-scale structure surveys and allows model-independent errors on cosmological parameters. Using the SDSS-III BOSS CMASS sample, we study how the jackknife size and number of resamplings impact the precision of the covariance estimate on the correlation function multipoles and the error on the inferred baryon acoustic scale. We compare the measurement with the MultiDark Patchy mock galaxy catalogues, and we also validate it against a set of lognormal mocks with the same survey geometry. We build several jackknife configurations that vary in size and number of resamplings. We introduce the Hartlap factor in the covariance estimate that depends on the number of jackknife resamplings. We also find that it is useful to apply the tapering scheme to estimate the precision matrix from a limited number of resamplings. The results from CMASS and mock catalogues show that the error estimate of the baryon acoustic scale does not depend on the jackknife scale. For the shift parameter α, we find an average error of 1.6 per cent, 2.2 per cent and 1.2 per cent, respectively, from CMASS, Patchy, and lognormal jackknife covariances. Despite these uncertainties fluctuate significantly due to some structural limitations of the jackknife method, our α estimates are in reasonable agreement with published pre-reconstruction analyses. Jackknife methods will provide valuable and complementary covariance estimates for future large-scale structure surveys.
Stabilization of Hfq-mediated translational repression by the co-repressor Crc in Pseudomonas aeruginosa
Authors: Malecka Ewelina M , Bassani Flavia , Dendooven Tom , Sonnleitner Elisabeth , Rozner Marlena , Albanese Tanino G , Resch Armin , Luisi Ben , Woodson Sarah , Bläsi Udo 
Published: June 2021

Abstract
In Pseudomonas aeruginosa the RNA chaperone Hfq and the catabolite repression control protein (Crc) govern translation of numerous transcripts during carbon catabolite repression. Here, Crc was shown to enhance Hfq-mediated translational repression of several mRNAs. We have developed a single-molecule fluorescence assay to quantitatively assess the cooperation of Hfq and Crc to form a repressive complex on a RNA, encompassing the translation initiation region and the proximal coding sequence of the P. aeruginosa amiE gene. The presence of Crc did not change the amiE RNA-Hfq interaction lifetimes, whereas it changed the equilibrium towards more stable repressive complexes. This observation is in accord with Cryo-EM analyses, which showed an increased compactness of the repressive Hfq/Crc/RNA assemblies. These biophysical studies revealed how Crc protein kinetically stabilizes Hfq/RNA complexes, and how the two proteins together fold a large segment of the mRNA into a more compact translationally repressive structure. In fact, the presence of Crc resulted in stronger translational repression in vitro and in a significantly reduced half-life of the target amiE mRNA in vivo. Although Hfq is well-known to act with small regulatory RNAs, this study shows how Hfq can collaborate with another protein to down-regulate translation of mRNAs that become targets for the degradative machinery.
The Impact of Instrumentation and Implant Surface Technology on Cervical and Thoracolumbar Fusion
Authors: Wang Timothy Y , Mehta Vikram A , Sankey Eric W , Shaffrey Christopher I , Abd-El-Barr Muhammad M , Than Khoi D 
Published: June 2021

Abstract
Spinal fusion has undergone significant evolution and improvement over the past 50 yr. Historically, spine fusion was noninstrumented and arthrodesis was based entirely on autograft. Improved understanding of spinal anatomy and materials science ushered in a new era of spinal fusion equipped with screw-based technologies and various interbody devices. Osteobiologics is another important realm of spine fusion, and the evolution of various osteobiologics has perhaps undergone the most change within the past 20 yr. A new element to spinal instrumentation has recently gained traction—namely, surface technology. New data suggest that surface treatments play an increasingly well-recognized role in inducing osteogenesis and successful fusion. Until now, however, there has yet to be a unified resource summarizing the existing data and a lack of consensus exists on superior technology. Here, authors provide an in-depth review on surface technology and its impact on spinal arthrodesis.
QuantitativeIn Vitro-to-In VivoExtrapolation for Mixtures: A Case Study of Superfund Priority List Pesticides
Authors: Valdiviezo Alan , Luo Yu-Syuan , Chen Zunwei , Chiu Weihsueh A , Rusyn Ivan 
Published: June 2021

AbstractIn vitro cell-based toxicity testing methods generate large amounts of data informative for risk-based evaluations. To allow extrapolation of the quantitative outputs from cell-based tests to the equivalent exposure levels in humans, reverse toxicokinetic modeling is used to conduct in vitro-to-in vivo extrapolation (IVIVE) from in vitro effective concentrations to in vivo oral dose equivalents. IVIVE modeling approaches for individual chemicals are well-established; however, the potential implications of chemical-to-chemical interactions in mixture settings on IVIVE remain largely unexplored. We hypothesized that chemical coexposures could modulate both protein binding efficiency and hepatocyte clearance of the chemicals in a mixture, which would in turn affect the quantitative IVIVE toxicokinetic parameters. To test this hypothesis, we used 20 pesticides from the Agency for Toxic Substances and Disease Registry Substance Priority List, both individually and as equimolar mixtures, and investigated the concentration-dependent effects of chemical interactions on in vitro toxicokinetic parameters. Plasma protein binding efficiency was determined by using ultracentrifugation, and hepatocyte clearance was estimated in suspensions of cryopreserved primary human hepatocytes. We found that for single chemicals, the protein binding efficiencies were similar at different test concentrations. In a mixture, however, both protein binding efficiency and hepatocyte clearance were affected. When IVIVE was conducted using mixture-derived toxicokinetic data, more conservative estimates of activity-to-exposure ratios were produced as compared with using data from single chemical experiments. Because humans are exposed to mixtures of chemicals, this study is significant as it demonstrates the importance of incorporating mixture-derived parameters into IVIVE for in vitro bioactivity data in order to accurately prioritize risks and facilitate science-based decision-making.
Suppression of Extracellular Signal‐regulated Kinase‐1/2 Causes Fat Accumulation in Hepatocytes: A Potential Mechanism in Alcoholic Fatty Liver Disease (ALD)
Authors: Wang Zhigang , Yao Tong , Song Zhenyuan 
Published: June 2021

Although much progress has been made, the underlying mechanism in alcohol‐induced hepatic steatosis is still obscure. In this study, we examined the effect of alcohol exposure on MEK/ERK1/2 activation and its potential involvement in the development of hepatic steatosis. In animal studies, male C57BL/6 mice were pair‐fed with liquid diets containing either ethanol or an isocaloric maltose‐dextrin mixture for four weeks. In the in vitro investigations, HepG2 cells were utilized. Our results showed that chronic alcohol feeding resulted in increased triglyceride accumulation in the liver and liver injury in mice. These observations were concomitant with decreased S‐adenosylmethionine/S‐adenosylhomocysteine ratio and suppressed ERK 1/2 activation in the liver. Using HepG2 cells, we found that ERK inhibition by U0126 elevated intracellular triglyceride contents, and this was associated with increased gene expression of diacylglycerol acyltransferase‐2 (DGAT2). In contrast, epidermal growth factor, a major activator of ERK1/2, reduced triglyceride synthesis. Furthermore, N‐acetyl‐S‐farnesyl‐L‐cysteine (AFC), a methyltrasferase inhibitor, elevated triglyceride synthesis, which is associated with ERK ½ inhibition and enhanced DGAT2 expression. Taken together, our findings suggest that suppression of ERK‐1/2 activation may play a mechanistic role in the development of ALD.Supported by the National Institutes of Health grants K01 AA015344 and R01 AA017442 (Z Song).