bluuebunny/crossref_metadata_2025_split huggingface dataset:
AI/ML assisted shale gas production performance evaluation
Authors: Syed Fahad I. , Muther Temoor , Dahaghi Amirmasoud K. , Negahban Shahin 
Published: August 2021

AbstractShale gas reservoirs are contributing a major role in overall hydrocarbon production, especially in the United States, and due to the intense development of such reservoirs, it is a must thing to learn the productive methods for modeling production and performance evaluation. Consequently, one of the most adopted techniques these days for the sake of production performance analysis is the utilization of artificial intelligence (AI) and machine learning (ML). Hydrocarbon exploration and production is a continuous process that brings a lot of data from sub-surface as well as from the surface facilities. Availability of such a huge data set that keeps on increasing over time enhances the computational capabilities and performance accuracy through AI and ML applications using a data-driven approach. The ML approach can be utilized through supervised and unsupervised methods in addition to artificial neural networks (ANN). Other ML approaches include random forest (RF), support vector machine (SVM), boosting technique, clustering methods, and artificial network-based architecture, etc. In this paper, a systematic literature review is presented focused on the AI and ML applications for the shale gas production performance evaluation and their modeling.
Exosomes as cell-derivative carriers in the diagnosis and treatment of central nervous system diseases
Authors: Shetgaonkar Gayatri Gopal , Marques Shirleen Miriam , DCruz Cleona E. M. , Vibhavari R. J. A. , Kumar Lalit , Shirodkar Rupesh Kalidas 
Published: August 2021

AbstractExosomes are extracellular vesicles with the diameter ranging from 50 to 100 nm and are found in different body fluids such as blood, cerebrospinal fluid (CSF), urine and saliva. Like in case of various diseases, based on the parent cells, the content of exosomes (protein, mRNA, miRNA, DNA, lipids and metabolites) varies and thus can be utilized as potential biomarker for diagnosis and prognosis of the brain diseases. Furthermore, utilizing the natural potential exosomes to cross the blood–brain barrier and by specifically decorating it with the ligand as per the desired brain sites therapeutics can be delivered to brain parenchyma. This review article conveys the importance of exosomes and their use in the treatment and diagnosis of brain/central nervous system diseases.
Graphical abstract
Thermal and mechanical characteristics of local firewood species and resulting charcoal produced by slow pyrolysis
Authors: Lubwama Michael , Yiga Vianney Andrew , Ssempijja Ivan , Lubwama Harriet Nalubega 
Published: August 2021

AbstractThe main source of fuel for domestic cooking applications in Sub-Saharan Africa is either locally available firewood species or charcoal produced by slow pyrolysis of these species. However, very few studies exist that characterize and quantify physical properties, burning rates, peak temperatures, and calorific values of typical firewood species and resulting charcoal fuels produced by slow pyrolysis. This study evaluated the mechanical and thermal properties of firewood and charcoal from five tree species namely:Dichrostachys cinerea,Morus Lactea,Piliostigma thonningii,Combretum molle, andAlbizia grandibracteata. Characterization was done by scanning electron microscopy, thermogravimetric analysis, bomb calorimetry, Fourier transform infrared spectroscopy, bulk density measurements, and durability, water boiling and absorption tests. SEM images showed the development of macropores on charcoal after slow pyrolysis. Peak temperatures during firewood and charcoal combustion ranged between 515.5–621.8 °C and 741.6–785.9 °C, respectively. Maximum flame temperatures ranged between 786.9–870.8 °C for firewood and 634.4–737.3 °C for charcoal. Bulk densities and calorific values of charcoal species were higher than those for firewood species. Drop strengths for firewood were all 100% while for charcoal were between 93.7 and 100%. Water boiling tests indicated that firewood fuel performed better that charcoal fuel for low amounts of water due to higher maximum flame temperatures obtained during combustion of firewood.
Lightlike hypersurfaces in spaces with concircular fields
Authors: Ssekajja Samuel 
Published: August 2021

AbstractLightlike hypersurfaces in semi-Riemannian manifolds admitting concircular vector fields are investigated. We prove that such hypersurfaces are generally products of lightlike curves and warped product manifolds. In special cases, we show that these hypersurfaces are totally geodesic or totally screen geodesic provided such concircular fields belong to their normal or transversal bundles. A number of examples are furnished, where possible, to illustrate the main concepts.
National Cardiovascular Data Registry-Acute Kidney Injury (NCDR) vs. Mehran risk models for prediction of contrast-induced nephropathy and need for dialysis after coronary angiography in a German patient cohort
Authors: Parco Claudio , Brockmeyer Maximilian , Kosejian Lucin , Quade Julia , Tröstler Jennifer , Bader Selina , Lin Yingfeng , Sokolowski Alexander , Hoss Alexander , Heinen Yvonne , Schulze Volker , Icks Andrea , Jung Christian , Kelm Malte , Wolff Georg 
Published: August 2021

AbstractBackgroundContrast-induced nephropathy (CIN) is a major adverse event in patients undergoing coronary angiography. The Mehran risk model is the gold-standard for CIN risk prediction. However, its performance in comparison to more contemporary National Cardiovascular Data Registry-Acute Kidney Injury (NCDR-AKI) risk models remains unknown. We aimed to compare both in this study.Methods and resultsPredictions of Mehran and NCDR-AKI risk models and clinical events of CIN and need for dialysis were assessed in a total of 2067 patients undergoing coronary angiography with or without percutaneous coronary intervention. Risk models were compared regarding discrimination (receiver operating characteristic analysis), net reclassification improvement (NRI) and calibration (graphical and statistical analysis). The NCDR risk model showed superior risk discrimination for predicting CIN (NCDR c-index 0.75, 95% CI 0.72–0.78; vs. Mehran c-index 0.69, 95% CI 0.66–0.72, p < 0.01), and continuous NRI (0.22; 95% CI 0.12–0.32; p < 0.01) compared to the Mehran model. The NCDR risk model tended to underestimate the risk of CIN, while the Mehran model was more evenly calibrated. For the prediction of need for dialysis, NCDR-AKI-D also discriminated risk better (c-index 0.85, 95% CI 0.79–0.91; vs. Mehran c-index 0.75, 95% CI 0.66–0.84; pNCDRvsMehran < 0.01), but continuous NRI showed no benefit and calibration analysis revealed an underestimation of dialysis risk.ConclusionIn German patients undergoing coronary angiography, the modern NCDR risk model for predicting contrast-induced nephropathy showed superior discrimination compared to the Mehran model while showing less accurate calibration. Results for the outcome ‘need for dialysis’ were equivocal.Graphic abstract
Incidence of persistent and high-risk human papillomavirus infection and associated factors among HIV-positive women in China, 2015–2016
Authors: Qiao Yaping , Wang Ailing , Fang Liwen , Wang Linhong 
Published: August 2021

AbstractBackgroundPersistent human papillomavirus (HPV) infection is the necessary factor for cervical cancer. Human immunodeficiency virus (HIV)-positive women are a high-risk population for cervical cancer, but little is known about persistent HPV infection among HIV-positive women in China. We aimed to investigate the persistence and incidence of infection with high-risk HPV (hrHPV) and associated factors among HIV-positive women in China.MethodUsing a prospective observational study design, we collected data from 670 HIV-positive women in five counties of three provinces through interviews, medical record reviews, health examination, and laboratory tests at a baseline survey in 2015 and a follow-up survey in 2016. We tested HIV-positive women for hrHPV infection using the Cobas 4800 HPV test, and analyzed factors associated with persistence and new incidence of hrHPV infection using logistic regression.ResultsAfter an average of 15 months at follow-up, the persistence and new incidence rates of hrHPV infection were 38.0% (46/121, 95%CI: 29.2%–46.8%) and 8.3% (35/420,95%CI: 5.7%–11.1%), respectively. HIV-positive women in Yunnan and Guangxi were more likely to have persistent hrHPV infections than those in Xinjiang (aOR = 3.18, 95%CI: 1.00–10.14, p = 0.05; aOR = 6.38, 95%CI: 2.29–17.77,p < 0.001). Migrant women had a higher rate of new hrHPV incidence than local women (aOR = 4.48, 95%CI: 1.65–12.15,p = 0.003). HIV-positive women from Xinjiang were 6.5 times more likely to be newly infected with hrHPV than those from Yunnan (95%CI: 2.40–17.60, p < 0.001). HIV-positive women with HBV infection had a higher risk of being infected with hrHPV than those without HBV infection (aOR = 3.48, 95%CI: 1.13–10.71,p = 0.029).ConclusionsThe persistence and new incidence rates of hrHPV infection among HIV-positive women were high and varied significantly between regions. HBV infection and being among the migrant population were associated with new hrHPV infection.
Assessing the Performance of Water and Sanitation Tariffs: The Case of Nairobi, Kenya
Authors: Fuente David , Kabubo‐Mariara Jane , Kimuyu Peter , Mwaura Mbutu , Whittington Dale 
Published: August 2021

AbstractPolicymakers and utility managers can use a variety of tariff structures to calculate customers' bills for water and sanitation services, ranging from a simple fixed monthly fee to complicated multi‐part tariffs with seasonal pricing based on metered water use. This study examines the performance of several alternative tariff structures for water and wastewater services in Nairobi, Kenya using a dynamic tariff simulation model applied to a complete set of billing records from Nairobi City Water and Sewer Company. Simulations show that a uniform volumetric price tariff structure performs as well as or better than several increasing block tariff (IBT) structures across the six performance metrics considered (customer welfare, social welfare, cost recovery, the subsidy delivered through the tariff, subsidy incidence, and water conservation). These findings are robust to changes in the level of cost recovery. This finding challenges the wisdom of the widespread use of IBTs in low‐ and middle‐income countries and current perceptions of best practice in tariff design.
High‐Resolution Ambient Noise Imaging of Geothermal Reservoir Using 3C Dense Seismic Nodal Array and Ultra‐Short Observation
Authors: Cheng Feng , Xia Jianghai , Ajo‐Franklin Jonathan B. , Behm Michael , Zhou Changjiang , Dai Tianyu , Xi Chaoqiang , Pang Jingyin , Zhou Changwei 
Published: August 2021

AbstractTomographic imaging based on long‐term ambient seismic noise measurements, mainly the phase information from surface waves, has been shown to be a powerful tool for geothermal reservoir imaging and monitoring. In this study, we utilize seismic noise data from a dense nodal array (192 3C nodes within 20 ) over a ultra‐short observation period (4.7 days) to reconstruct surface waves and determine the high‐resolution (0.2 km) three‐dimensional (3‐D) S wave velocity structure beneath a rural town in Zhejiang, China. We report the advantage of cross‐coherence over cross‐correlation in suppressing pseudo‐arrivals caused by persistent sources. We use ambient noise interferometry to retrieve high quality Rayleigh waves and Love waves. Body waves are also observed on the R‐R component interferograms. We apply phase velocity dispersion measurements on both Rayleigh waves and Love waves and automatically pick more than 23,000 dispersion curves by using a Machine Learning technique. 3‐D surface wave tomographic results after depth inversion indicate low‐velocity anomalies (between −1% and −4%) from the surface to 2 km depth in the central area. Combined with the conductive characteristics observed on resistivity profile, the low‐velocity anomalies are inferred to be a fluid saturated zone of highly fractured rock. Joint interpretation based on horizontal‐to‐vertical spectral ratio (HVSR) measurements, and existing temperature and fluid resistivity records observed in a nearby well, suggests the existence of the high‐temperature geothermal field through the fracture channel. Strong correlation between HVSR measurements and the S wave velocity model highlights the potential of extraction of both amplitude and phase information from ambient noise.
Infrasound Radiation From Impulsive Volcanic Eruptions: Nonlinear Aeroacoustic 2D Simulations
Authors: Watson Leighton M. , Dunham Eric M. , Mohaddes Danyal , Labahn Jeff , Jaravel Thomas , Ihme Matthias 
Published: August 2021

AbstractInfrasound observations are increasingly used to constrain properties of volcanic eruptions. In order to better interpret infrasound observations, however, there is a need to better understand the relationship between eruption properties and sound generation. Here we perform two‐dimensional computational aeroacoustic simulations where we solve the compressible Navier‐Stokes equations for pure‐air with a large‐eddy simulation approximation. We simulate idealized impulsive volcanic eruptions where the exit velocity is specified and the eruption is pressure‐balanced with the atmosphere. Our nonlinear simulation results are compared with the commonly used analytical linear acoustics model of a compact monopole source radiating acoustic waves isotropically in a half space. The monopole source model matches the simulations for low exit velocities ( m/s or where is the Mach number); however, the two solutions diverge as the exit velocity increases with the simulations developing lower peak amplitude, more rapid onset, and anisotropic radiation with stronger infrasound signals recorded above the vent than on Earth's surface. Our simulations show that interpreting ground‐based infrasound observations with the monopole source model can result in an underestimation of the erupted volume for eruptions with sonic or supersonic exit velocities. We examine nonlinear effects and show that nonlinear effects during propagation are relatively minor for the parameters considered. Instead, the dominant nonlinear effect is advection by the complex flow structure that develops above the vent. This work demonstrates the need to consider anisotropic radiation patterns and jet dynamics when interpreting infrasound observations, particularly for eruptions with sonic or supersonic exit velocities.
Can Short‐Wave Nonlinearity Affect the Prediction of Wave Setup?
Authors: Guérin Thomas , Ruessink Gerben 
Published: August 2021

AbstractBased on high‐resolution laboratory data of instantaneous surface elevation and fluid velocity associated with the propagation of short waves over a gently sloping beach (GLOBEX project), the present work compares two methods for predicting the wave setup. A one‐dimensional (cross‐shore) model is considered to solve the balance equation that links the pressure gradient induced by the mean surface elevation profile with the wave radiation stress (including wave roller) and bottom stress profiles. When compared to measurements and using a wave‐by‐wave approach, the mean elevation appears to be significantly better predicted with a nonlinear approach based on stream function theory than with the commonly used linear approach based on Airy wave theory. At the shoreline, the linear method overestimates the wave setup by at least about while this error is globally reduced by a factor 2 to 4 in the nonlinear case. In the framework of this study, the combined contribution of bottom stress and wave roller to the wave setup appears secondary since it accounts for about of the predicted setup at the shoreline. Alternative computational methods are also considered to model the wave setup. In the linear case, using a spectral instead of the wave‐by‐wave approach greatly improves the wave setup predictions. This improvement is related to the disparity between the representative wave height (and thus the wave energy) obtained from spectral and wave‐by‐wave analysis when short‐wave nonlinearity becomes significant.
Winter Dynamics in an Epishelf Lake: Quantitative Mixing Estimates and Ice Shelf Basal Channel Considerations
Authors: Bonneau Jérémie , Laval Bernard E. , Mueller Derek , Hamilton Andrew K. , Friedrichs Andrew M. , Forrest Alexander L. 
Published: August 2021

AbstractMilne Ice Shelf is located at the mouth of Milne Fiord (82.6°N, 81.0°W), on Ellesmere Island, Nunavut. This floating ice feature is attached to both sides of the fjord. During the melt season, the ice shelf acts as a floating barrier preventing surface runoff in Milne Fiord from flowing freely to the ocean. This results in a permanent layer of freshwater that floats on top of the seawater of the fjord, commonly known as an epishelf lake. Few studies address the physical characteristics of epishelf lakes. Here, winter data from a mooring installed in Milne Fiord epishelf lake during 2011–2019 is analyzed in the framework of a one‐dimensional model in order to study mixing in the upper water column and infer the characteristics of a basal channel in the ice shelf. The results show that vertical mixing rates are higher in the epishelf lake than in the seawater below. Estimation of the Richardson number using a geostrophic balance approach reveals that enhanced mixing in the epishelf lake is associated with horizontal temperature gradients. In contrast to most studies on basal channels in Greenland and Antarctica, the results presented here show the basal channel of Milne Ice Shelf is apparently not evolving (melting) rapidly.
Surface Heat and Moisture Exchange in the Marginal Ice Zone: Observations and a New Parameterization Scheme for Weather and Climate Models
Authors: Elvidge A. D. , Renfrew I. A. , Brooks I. M. , Srivastava P. , Yelland M. J. , Prytherch J. 
Published: August 2021

AbstractAircraft observations from two Arctic field campaigns are used to characterize and model surface heat and moisture exchange over the marginal ice zone (MIZ). We show that the surface roughness lengths for heat and moisture over uninterrupted sea ice vary with roughness Reynolds number (; itself a function of the roughness length for momentum, , and surface wind stress), with a peak at the transition between aerodynamically smooth (<0.135) and aerodynamically rough (>2.5) regimes. A pre‐existing theoretical model based on surface‐renewal theory accurately reproduces this peak, in contrast to the simple parameterizations currently employed in two state‐of‐the‐art numerical weather prediction models, which are insensitive to . We propose a new, simple parameterization for surface exchange over the MIZ that blends this theoretical model for sea ice with surface exchange over water as a function of sea ice concentration. In offline tests, this new scheme performs much better than the existing schemes for the rough conditions observed during the ‘Iceland Greenland Seas Project’ field campaign. The bias in total turbulent heat flux across the MIZ is reduced to only 13 W m−2 for the new scheme, from 48 and 80 W m−2 for the Met Office Unified Model and ECMWF Integrated Forecast System schemes, respectively. It also performs marginally better for the comparatively smooth conditions observed during the ‘Aerosol‐Cloud Coupling and Climate Interactions in the Arctic’ field campaign. The new surface exchange scheme has the benefit of being physically‐motivated, comparatively accurate and straightforward to implement, although to reap the full benefits an improvement to the representation of sea ice topography via is required.
Multi‐Sensor Fusion for Transient‐Based Pipeline Leak Localization in the Dempster‐Shafer Evidence Framework
Authors: Lin Jingrong , Wang Xun , Ghidaoui Mohamed S. 
Published: August 2021

AbstractDetecting a small leak in a water‐supply pipe with a wave scattering power of the order of noise or smaller is a challenging problem because its signature in a measured signal is weak. Experimental data show that multiple sensors enhance the evidence about a leak in a transient test and, thus, increase the possibility of successful leak detection in noisy environments. Therefore, a leakage localization scheme is proposed, which fuses multi‐sensor measurements in the Dempster‐Shafer evidence framework. The signature of a leak in each measurement is extracted and translated into a piece of evidence regarding its presence and location. Then, the pieces of evidence from different sensors are fused using the Dempster's rule of combination to form a unified leak location estimation. The proposed method is model‐free and is thus insensitive to imprecise knowledge of pipe system. The gain of the multi‐sensor fusion mechanism on the leakage localization accuracy is demonstrated via both numerical and experimental data.
Ursodeoxycholic acid suppresses the malignant progression of colorectal cancer through TGR5-YAP axis
Authors: Zhang Huan , Xu Huanji , Zhang Chenliang , Tang Qiulin , Bi Feng 
Published: August 2021

AbstractThe Hippo/YAP pathway plays an important role in the development of cancers. Previous studies have reported that bile acids can activate YAP (Yes Associated Protein) to promote tumorigenesis and tumor progression. Ursodeoxycholic acid (UDCA) is a long-established old drug used for cholestasis treatment. So far, the effect of UDCA on YAP signaling in colorectal cancer (CRC) is not well defined. This study means to explore relationship of UDCA and YAP in CRC. UDCA suppressed YAP signaling by activating the membrane G-protein-coupled bile acid receptor (TGR5). TGR5 mainly regulated cAMP/PKA signaling pathway to inhibit RhoA activity, thereby suppressing YAP signaling. Moreover, the restoration of YAP expression alleviated the inhibitory effect of UDCA on CRC cell proliferation. In AOM/DSS-induced CRC model, UDCA inhibited tumor growth in a concentration-dependent manner and decreased expression of YAP and Ki67. UDCA plays a distinguished role in regulating YAP signaling and CRC growth from the primary bile acids and partial secondary bile acids, demonstrating the importance of maintaining normal intestinal bile acid metabolism in cancer patients. It also presents a potential therapeutic intervention for CRC.
Rotor loss and temperature variation under single and combined faults composed of static air‐gap eccentricity and rotor inter‐turn short circuit in synchronous generators
Authors: He Yu‐Ling , Zhang Wen , Xu Ming‐Xing , Tao Wen‐Qiang , Liu Hui‐Lan , Dou Long‐Jiang , Wan Shu‐Ting , Li Jun‐Qing , Gerada David 
Published: August 2021

AbstractIn this study, the rotor loss as well as the temperature variations due to the static air‐gap eccentricity (SAGE) and the rotor inter‐turn short circuit (RISC) in synchronous generators is presented. Different from the previous studies, this study investigates the loss/temperature changes under not only the single SAGE fault and the single RISC fault but also the combined faults (CF) that are composed of these two single faults. Detailed formula derivation on the hysteresis loss (HL) and the eddy current loss (ECL), together with the rotor temperature rise due to varied fault types and different operating conditions, are first carried out based on a theoretical analysis of the magnetic flux density (MFD) variation. Then, 3‐D finite element analysis (FEA) and experimental verifications are performed on a CS‐5 prototype generator that has two poles and a rated rotating speed of 3000 rpm. It shows that the occurrence of either SAGE or RISC will increase the rotor loss and temperature. Comparatively, the single RISC fault overweighs the single SAGE fault in the rotor temperature increment, while the combined fault overweighs both of these single faults. In the same fault cases, the rotor temperature will have the highest value under full‐load operation.