bluuebunny/crossref_metadata_2025_split huggingface dataset:
High-throughput screening identifies established drugs as SARS-CoV-2 PLpro inhibitors
Authors: Zhao Yao , Du Xiaoyu , Duan Yinkai , Pan Xiaoyan , Sun Yifang , You Tian , Han Lin , Jin Zhenming , Shang Weijuan , Yu Jing , Guo Hangtian , Liu Qianying , Wu Yan , Peng Chao , Wang Jun , Zhu Chenghao , Yang Xiuna , Yang Kailin , Lei Ying , Guddat Luke W. , Xu Wenqing , Xiao Gengfu , Sun Lei , Zhang Leike , Rao Zihe , Yang Haitao 
Published: April 2021

AbstractA new coronavirus (SARS-CoV-2) has been identified as the etiologic agent for the COVID-19 outbreak. Currently, effective treatment options remain very limited for this disease; therefore, there is an urgent need to identify new anti-COVID-19 agents. In this study, we screened over 6,000 compounds that included approved drugs, drug candidates in clinical trials, and pharmacologically active compounds to identify leads that target the SARS-CoV-2 papain-like protease (PLpro). Together with main protease (Mpro), PLpro is responsible for processing the viral replicase polyprotein into functional units. Therefore, it is an attractive target for antiviral drug development. Here we discovered four compounds, YM155, cryptotanshinone, tanshinone I and GRL0617 that inhibit SARS-CoV-2 PLpro with IC50 values ranging from 1.39 to 5.63 μmol/L. These compounds also exhibit strong antiviral activities in cell-based assays. YM155, an anticancer drug candidate in clinical trials, has the most potent antiviral activity with an EC50 value of 170 nmol/L. In addition, we have determined the crystal structures of this enzyme and its complex with YM155, revealing a unique binding mode. YM155 simultaneously targets three “hot” spots on PLpro, including the substrate-binding pocket, the interferon stimulating gene product 15 (ISG15) binding site and zinc finger motif. Our results demonstrate the efficacy of this screening and repurposing strategy, which has led to the discovery of new drug leads with clinical potential for COVID-19 treatments.
Novel UV-activated biofunctionalization of up-converting nanocrystals for detection of proteins
Authors: Misiak Małgorzata , Gawłowski Maciej , Kowalczyk Agnieszka , Skowicki Michał , Prorok Katarzyna , Lipiński Tomasz 
Published: April 2021

AbstractLanthanide doped nanocrystals capable to emit higher energy photons under excitation with lower energy radiation are promising for a broad range of applications including biodetection, biosensing, and bioimaging. However, the adaptation of these nanoparticles to the biological environment that requires good water-solubility, stability and ease of further functionalization still remains a challenge. The application of nanoparticles for biodetection or in various assays encountered many difficulties arising mainly from the strong tendency of nanoparticles for aggregation or nonspecific binding. Here we present a new method to obtain soluble and stable in water-based buffers NaYF4:Yb3+Er3+ nanocrystals with modified surface ready for further conjugation with biomolecules. In the presented approach polyvinylpyrrolidone/vinyl alcohol copolymer (PVP/VA) with photo-activatable linker (N-5-Azido-2-nitrobenzoyl group—ANB-NOS) was used for initial coating due to its high non-covalent affinity to nanoparticles surface. Subsequent coating with aminated dextran by ultraviolet light activation of ANB-NOS was carried out. This step has a significant impact on nanocrystals stability in the physiological buffer as well as on protein conjugation. Conjugation of biomolecules was possible by employing another photo-linker—sulfosuccinimidyl 4,4′-azipentanoate (sulfo-SDA). Bacterial Protein G has been selected to create a universal immune-imaging agent due to its ability to bind Fc fragment of most mammalian immunoglobulins. Moreover, the direct attachment of antibodies to nanoparticles was also examined. The activity of biofunctionalized nanocrystals was tested in immunoblot test, that confirmed preserved activity of attached molecules and lack of undesired nonspecific binding or precipitation on the assay membrane.
Graphic abstract
Simply structured controllers for vibration suppression in long rotors
Authors: Aleyaasin Majid 
Published: April 2021

AbstractIn this paper suppression of the transient flexural vibrational disturbances in long rotors, with fluid film bearings, is investigated. The rotor is described by a series of distributed shafts connected by the lumped discs, and the system is mounted on lumped fluid film bearings. Upon determination of the dynamic stiffness matrix of the system, the best approximate transfer function matrix description of the rotor, is determined. Initially vibration suppression by simple diagonal Proportional + Integral (PI) controllers is studied and via direct search optimisation techniques the PI parameters which exhibit fast vibration suppression is found. The resulted high integration rate, and low proportional gain PI controller, theoretically provided fast suppression time. However, it is shown that due to the strong coupling effect in the rotor system, and high rate of integration, the closed loop relative stability is weak, and feasibility of controller is questionable. Therefore, an alternative simple first order controller without integration action, that is named “attenuation filter “is suggested that can produce stronger stability and produces significant (not full) vibration suppression. The closed loop multivariable control of the rotor system comprising two vibration sensors and two magnetic actuators using such attenuation filter, is then simulated. The response to step disturbances, has provided 95% suppression with significantly fast response. It is concluded that although the attenuation filter may not provide 100% suppression, but it more reliable since the integration of the error, that results weak stability is avoided.
Assessing the long-term potential of fiber reinforced polymer composites for sustainable marine construction
Authors: Kappenthuler Steve , Seeger Stefan 
Published: April 2021

AbstractFiber reinforced polymer composites (FRPC) have gain rapid interest as light-weight and corrosion-resistant materials for various applications in marine infrastructure. Despite their advantages, FRPCs are still susceptible to other environmental factors present in the marine environment and manufactured mostly from non-renewable materials. This greatly affects the overall economic and environmental sustainability of such components. To determine the long-term suitability of various FRPCs for use in marine environments, this paper provides a holistic comparison of the performance of 16 FRPCs (four fiber types: glass, carbon, natural, basalt; and four polymer resins: epoxy, polyester, vinylester, thermoplastic) not only from a technical, but also from an economic, environmental and resource perspective. The resulting ranking not only assesses each material’s long-term potential, but also provides a detailed overview of individual strengths and weaknesses. Although ranked the lowest of all materials, the partial renewability of the natural fiber composites makes them an interesting material in the longer term. Therefore, we use the framework to evaluate a number of approaches aimed at improving the overall performance of these composites.
What Impact Will the New-Built Metro Bring to the Transportation of Second-Tier Cities? From the Perspective of a Multilayer Complex Network
Authors: Zhao Fang , Cao Hongmei , Lu Tianwei 
Published: April 2021

AbstractMetro is being developed rapidly in second-tier cities. There is a need to understand the impact it brings as it relates to the planning and management of the whole urban transportation system. In this paper, we applied the multilayer complex network theory to study this problem by contrasting the characteristics of transportation networks before and after the metro is built. We focused on transportation networks in second-tier cities and (1) proposed edge functions of the road subnetwork and rail transit subnetwork with impedance as weight; (2) established an interlayer function based on the transfer behavior to couple the above subnetworks into the multilayer weighted transportation network; and (3) redefined statistical parameters, such as node strength, chessboard coefficient, and average least pass cost. At last, Hohhot, China, a typical second-tier city, was taken as a case study. Calculations show that the new-built metro network in the second-tier city increases convenience and reduces travel cost, whereas, the vulnerability of the whole network increases, and the distribution of key nodes in the road network is reconstructed. For the sustainable development of urban transportation, more attention should be paid to the new-built metro in second-tier cities.
Biometric characteristics of the wild population of sea urchin Paracentrotus lividus (Lamarck, 1816) on the Tunisian coast
Authors: Sellem F. , Bouhaouala-Zahar B. 
Published: April 2021

AbstractThe present study was conducted to provide biometric data of the edible sea urchin Paracentrotus lividus along the Tunisian coastline where thirteen marine localities were selected randomly. A total of 653 individuals were collected and their metric and weight measurements were recorded. The size distribution of the different samples was determined and relative growth expressions were deduced. Data analysis showed that all localities’ samples of the wild population were dominated by one-size class, except Port Prince and Haouaria. Interestingly, only diameter-height relationships (D-H) were different between the geographical localities. Diameter-weight relationships (D-TW and D-TWTE) revealed a significant negative growth for all the localities, with the exception of Gammarth which showed positive growth for total weight (D-TW). Moreover, the multivariable analysis revealed divergences and/or similarities between metric and weight variables. Altogether, data highlights the inter-population discrimination with respect to geographic localization and clear segregation between the northern and the eastern localities demonstrated the plasticity of the species.
The selective cytotoxicity of silver thiosulfate, a silver complex, on MCF-7 breast cancer cells through ROS-induced cell death
Authors: Ota Akira , Tajima Masataka , Mori Kazunori , Sugiyama Erika , Sato Vilasinee Hirunpanich , Sato Hitoshi 
Published: April 2021

Abstract
Background
Silver is a transition metal that is known to be less toxic than platinum. However, only few studies have reported the anticancer effects of some silver complexes and their possibility as an alternative to platinum complex. This study investigated the anticancer effects of the silver thiosulfate complex (STS), [Ag(S2O3)2]3−, consisting of silver and sodium thiosulfate.

Methods
In vitro cytotoxic activity of STS was investigated comparatively in human cancer cell lines (K562 and MCF-7) and normal human cells (mesenchymal stem cells and mammary epithelial cells). For its anticancer effects, cell cycle, mode of cell death, morphological changes, and accumulation of intracellular ROS and GSH were evaluated in MCF-7 to provide mechanistic insights.

Results
STS showed a concentration-dependent cytotoxicity in MCF-7 cell, which was abolished by pretreatment with N-acetylcysteine, suggesting ROS accumulation by STS. Moreover, STS caused cell cycle arrest at the G1 phase, decrease in the GSH levels, and morphological changes in MCF-7. Direct measurement of ROS demonstrated the elevation of intracellular ROS accumulation in cancer cells treated with STS; however, neither cytotoxicity nor ROS accumulation was observed in normal human cells.

Conclusion
The results obtained here are the first evidence to show that STS exhibited an anticancer activity through ROS-induced mechanisms, and that its cytotoxicity is highly selective to cancer cells. The results of the present study warrant further investigation on the detailed mechanism of STS actions, as well as its in vivo effectiveness and safety for clinical application.
Low-carbon cast microalloyed steel intercritically heat-treated at different temperatures: microstructure and mechanical properties
Authors: Torkamani Hadi , Raygan Shahram , Garcia Mateo Carlos , Palizdar Yahya , Rassizadehghani Jafar , Vivas Javier , San-Martin David 
Published: April 2021

Abstract
In this study, dual-phase (DP, ferrite + martensite) microstructures were obtained by performing intercritical heat treatments (IHT) at 750 and 800 °C followed by quenching. Decreasing the IHT temperature from 800 to 750 °C leads to: (i) a decrease in the volume fraction of austenite (martensite after quenching) from 0.68 to 0.36; (ii) ~ 100 °C decrease in martensite start temperature (Ms), mainly due to the higher carbon content of austenite and its smaller grains at 750 °C; (iii) a reduction in the block size of martensite from 1.9 to 1.2 μm as measured by EBSD. Having a higher carbon content and a finer block size, the localized microhardness of martensite islands increases from 380 HV (800 °C) to 504 HV (750 °C). Moreover, despite the different volume fractions of martensite obtained in DP microstructures, the hardness of the steels remained unchanged by changing the IHT temperature (~ 234 to 238 HV). Applying lower IHT temperature (lower fraction of martensite), the impact energy even decreased from 12 to 9 J due to the brittleness of the martensite phase. The results of the tensile tests indicate that by increasing the IHT temperature, the yield and ultimate tensile strengths of the DP steel increase from 493 to 770 MPa, and from 908 to 1080 MPa, respectively, while the total elongation decreases from 9.8 to 4.5%. In contrast to the normalized sample, formation of martensite in the DP steels could eliminate the yield point phenomenon in the tensile curves, as it generates free dislocations in adjacent ferrite.
Characteristics of Atmospheric Aerosols Over the UAE Inferred From CALIPSO and Sun Photometer Aerosol Optical Depth
Authors: Nelli Narendra , Fissehaye Samson , Francis Diana , Fonseca Ricardo , Temimi Marouane , Weston Michael , Abida Rachid , Nesterov Oleksandr 
Published: April 2021

AbstractThis study provides insights on the composition and variability of atmospheric aerosols over the United Arab Emirates (UAE) by analyzing the atmospheric conditions together with 14 years (2006–2019) of aerosol optical depth (AOD) retrieved from CALIPSO (Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation) satellite, and 7 years of AOD measured from the ground‐based Aerosol Robotic Network (AERONET).We found that mineral dust is the most prevailing aerosol subtype. In addition, polluted dust and polluted continental aerosols are observed mostly in the cold season. The AOD is higher in spring and summer, when the atmospheric conditions are more favorable to the occurrence of dust events. Moreover, there is another peak in winter associated with dust storms triggered by mid‐latitude baroclinic systems. In summer’s daytime, extinction coefficients in excess of 0.2 km−1 are observed up to 3–4 km above the surface, as a result of the warmer and windier conditions. In the cold season and at night, the dust layers are confined to the lower atmosphere below 2 km. On a climatological time scale, we found that the AOD over the UAE has been decreasing since 2009, possibly due to the increasing trend in precipitation and changes in land use.This study highlights the large contribution of dust aerosols to the total aerosol load over the UAE and stresses on the need to account for mineral dust aerosols in climate‐air pollution related studies as well as weather and air quality forecasts.
Performance of the Ionospheric Kappa‐Correction of Radio Occultation Profiles Under Diverse Ionization and Solar Activity Conditions
Authors: Danzer J. , Haas S. J. , Schwaerz M. , Kirchengast G. 
Published: April 2021

AbstractThe kappa‐correction is an easy‐to‐use method to correct for residual ionospheric errors in radio occultation (RO) data. It is a simple empirical model term that only depends on readily available data. While its basic utility was well proven in previous studies, including a recent predecessor study on RO climatologies under solar cycle variations, its performance for individual RO profile correction under diverse and extreme ionization conditions is unclear so far. Here we tackle this gap and focus on investigating (extremely) low and high solar activity and ionization conditions of individual RO events, including inspection of ionospheric symmetry between inbound and outbound raypaths. Using a global multi‐year ensemble of MetOp‐A and GRACE‐A RO events over 2008–2015 as basis, we applied a sampling approach leading to six characteristic condition cases. These cases also relate to day and night time variations and geographic variations from the equatorial to the high latitude region. We inspected the kappa‐correction and its performance relative to the standard bending angle correction for RO‐retrieved stratospheric profiles and found mean deviations in temperature of near −0.3 K in the upper stratosphere (40–45 km) for high ionization conditions, with extreme deviations exceeding −2 K for strong inbound/outbound asymmetry. The kappa‐correction term itself reaches a mean value near 0.05 μrad under these high conditions. Low solar activity and ionization conditions lead to a mean correction smaller than 0.005 μrad and mean temperature deviations smaller than 0.02 K. An intercomparison to other quality datasets, predominantly showed a decrease in mean temperature difference when applying the kappa‐correction.
Evidence of Alfvenic Poynting Flux as the Primary Driver of Auroral Motion During a Geomagnetic Substorm
Authors: Tian S. , Colpitts C. A. , Wygant J. R. , Cattell C. A. , Ferradas C. P. , Igl A. B. , Larsen B. A. , Reeves G. D. , Donovan E. F. 
Published: April 2021

AbstractGeomagnetic substorms are major energy transfer events where energy stored in the Earth's magnetotail is released into the ionosphere. Substorm phenomena, including auroral activities, earthward Poynting flux, magnetic field dipolarization, etc, have been extensively studied. However, the complex interplay among them is not fully understood. In a fortuitous event on June 7, 2013, the twin Van Allen Probes (separated by 0.4 h in local time) observed bursts of earthward Alfvenic Poynting flux in the vicinity of the plasma sheet boundary layer (PSBL). The Poynting flux bursts correlate with enhancements of auroral brightness around the footpoints of both spacecraft. This indicates a temporal and spatial correlation between the auroral brightening and Poynting flux bursts, and that the auroral motion is directly linked to the perpendicular expansion of the Alfven wave. These observations suggest that the Alfvenic Poynting flux is a primary driver for the auroral electron acceleration. Around the time of auroral brightening, a dipolarization was seen to propagate more than 4 h in local time during a 20 min period. The azimuthal phase speed of this dipolarization (2 deg/min) is too small to explain the azimuthal motion of the aurora (13.6 deg/min), but the dipolarization could be related to the generation of the Alfvenic Poynting flux through phase mixing at strong density gradients like those in the PSBL.
Toward a Next Generation Particle Precipitation Model: Mesoscale Prediction Through Machine Learning (a Case Study and Framework for Progress)
Authors: McGranaghan Ryan M. , Ziegler Jack , Bloch Téo , Hatch Spencer , Camporeale Enrico , Lynch Kristina , Owens Mathew , Gjerloev Jesper , Zhang Binzheng , Skone Susan 
Published: April 2021

AbstractWe advance the modeling capability of electron particle precipitation from the magnetosphere to the ionosphere through a new database and use of machine learning (ML) tools to gain utility from those data. We have compiled, curated, analyzed, and made available a new and more capable database of particle precipitation data that includes 51 satellite years of Defense Meteorological Satellite Program (DMSP) observations temporally aligned with solar wind and geomagnetic activity data. The new total electron energy flux particle precipitation nowcast model, a neural network called PrecipNet, takes advantage of increased expressive power afforded by ML approaches to appropriately utilize diverse information from the solar wind and geomagnetic activity and, importantly, their time histories. With a more capable representation of the organizing parameters and the target electron energy flux observations, PrecipNet achieves a >50% reduction in errors from a current state‐of‐the‐art model oval variation, assessment, tracking, intensity, and online nowcasting (OVATION Prime), better captures the dynamic changes of the auroral flux, and provides evidence that it can capably reconstruct mesoscale phenomena. We create and apply a new framework for space weather model evaluation that culminates previous guidance from across the solar‐terrestrial research community. The research approach and results are representative of the “new frontier” of space weather research at the intersection of traditional and data science‐driven discovery and provides a foundation for future efforts.
Using Principal Component Analysis to Characterize the Variability of VLF Wave Intensities Measured by a Low‐Altitude Spacecraft and Caused by Interplanetary Shocks
Authors: Bezděková B. , Němec F. , Parrot M. , Kruparova O. , Krupar V. 
Published: April 2021

AbstractVery low frequency wave intensity measurements provided by the French low‐altitude DEMETER spacecraft are studied using the principal component analysis (PCA). We focus on both the physical interpretation of the first two principal components and their application to real physical problems. Variations of the first principal component (PC1) coefficients due to the geomagnetic activity and seasonal/longitudinal changes are studied. It is shown that their distribution corresponds to the wave intensity dependences obtained in previous studies. Moreover, the variations of PC1 coefficients around interplanetary shock arrivals are analyzed. The study is performed for fast forward (FF), fast reverse, slow forward, and slow reverse shocks separately. It shows that the most significant effect on the wave intensity is displayed in the FF case. Furthermore, it turns out that the wave intensity variations depend on the wave intensity detected before the shock arrival. Finally, the shock strength and interplanetary magnetic field orientation are also important. The performed analysis shows that PCA can be successfully applied to characterize large data sets of spacecraft measurements by limited sets of numbers—principal component coefficients (typically first one or two are enough), which still maintain a sufficient amount of information.
Data Assimilation Retrieval of Electron Density Profiles From Ionosonde Virtual Height Data
Authors: Forsythe Victoriya V. , Azeem Irfan , Blay Ryan , Crowley Geoff , Makarevich Roman A. , Wu Wanli 
Published: April 2021

AbstractA new method is developed to retrieve electron density profiles from a raw virtual height ionosonde traces. A Kalman filter is used for the assimilative inversion scheme together with the newly developed data‐driven vertical covariance model. The detailed mathematical formalism for the derivation of the Jacobian that takes into account the effect of the magnetic field is presented. The incoherent scatter radar measurements from Arecibo observatory are employed as the known truth to simulate the virtual height data. The results show that the data assimilative inversion technique accurately retrieves the vertical structure of the ionospheric density at the bottom side of the profile and reconstructs the vertical and temporal small‐scale density variations. A comparison with the results obtained by the POLynomial ANalysis (POLAN) inversion algorithm is presented. The assimilative inversion systematically outperforms the accuracy of the POLAN algorithm, on average reducing the percent errors in the electron density by half. Additionally, the simultaneous data ingestion is compared to the sequential assimilation of the virtual height data.