bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multistep Reaction Pathway for CO2 Reduction on Hydride‐Capped Si Nanosheets
Authors: Xia Lixue , Liao Xiaobin , He Qiu , Wang Huan , Zhao Yan , Truhlar Donald G. 
Published: January 2020

AbstractSilicon hydride, as a new efficient catalyst for CO2 conversion to CO, is receiving ever‐increasing attention. Thus, a precise catalytic mechanism is needed to provide a guideline for the design of new efficient catalysts based on silicon hydride. Qian et al. recently proposed a one‐step mechanism for the catalytic process. The present work, based on the recently proposed WMS and revM06 quantum mechanical model chemistries, provides a multistep mechanism that has a lower free energy of activation than the one‐step model. A key point in favor of the new mechanism is that it is consistent with experimental details of the infrared spectrum that cannot be explained by the previous mechanism.
Variable importance: Comparison of selectivity ratio and significance multivariate correlation for interpretation of latent‐variable regression models
Authors: Kvalheim Olav M. 
Published: January 2020

AbstractThis work examines the performance of significance multivariate correlation (sMC) and selectivity ratio (SR) for ranking variables according to their importance in latent‐variable regressions (LVRs) models. Both indices are based on target projection (TP) of a validated LVR model obtained by partial least squares (PLS). The matrix of explanatory x‐variables is projected on the normalized regression vector to obtain a score vector that is proportional to the vector of predicted values for the response variable y. sMC for each x‐variable is calculated by dividing the squared variance explained by the decomposition obtained from these two vectors on the squared residuals. This is similar to how SR is calculated except that for SR, the regression vector is replaced by the loading matrix obtained by projecting the data matrix of x‐variables onto the score matrix obtained by TP. The two indices for variable importance are compared for three different applications with data representing instrumental profiles from liquid chromatography, infrared spectroscopy, and proton nuclear magnetic spectroscopy. Results show that SR outperforms sMC for interpretation and biomarker selection. The main drawback of sMC appears to be the mixing of predictive and orthogonal variation resulting from the direct use of the normalized regression vector in the calculation. SR uses a loading vector that is proportional to the covariances between x‐variables and the predicted response variable.
Iron Porphyrin Allows Fast and Selective Electrocatalytic Conversion of CO2 to CO in a Flow Cell
Authors: Torbensen Kristian , Han Cheng , Boudy Benjamin , von Wolff Niklas , Bertail Caroline , Braun Waldemar , Robert Marc 
Published: January 2020

AbstractMolecular catalysts have been shown to have high selectivity for CO2 electrochemical reduction to CO, but with current densities significantly below those obtained with solid‐state materials. By depositing a simple Fe porphyrin mixed with carbon black onto a carbon paper support, it was possible to obtain a catalytic material that could be used in a flow cell for fast and selective conversion of CO2 to CO. At neutral pH (7.3) a current density as high as 83.7 mA cm−2 was obtained with a CO selectivity close to 98 %. In basic solution (pH 14), a current density of 27 mA cm−2 was maintained for 24 h with 99.7 % selectivity for CO at only 50 mV overpotential, leading to a record energy efficiency of 71 %. In addition, a current density for CO production as high as 152 mA cm−2 (>98 % selectivity) was obtained at a low overpotential of 470 mV, outperforming state‐of‐the‐art noble metal based catalysts.
Alkali Metal Triphenyl‐ and Trihydridosilanides Stabilized by a Macrocyclic Polyamine Ligand
Authors: Schuhknecht Danny , Leich Valeri , Spaniol Thomas P. , Douair Iskander , Maron Laurent , Okuda Jun 
Published: January 2020

AbstractPotassium silanide [KSiH3]∞ contains 4.2 wt % of hydrogen and has been intensely studied as hydrogen storage material. The macrocyclic ligand Me4TACD (1,4,7,10‐tetramethyl‐1,4,7,10‐tetraaminocyclododecane, L) stabilizes the full range of triphenylsilyl complexes [(L)MSiPh3]n (M=Li–Cs), which react with H2 or PhSiH3 to form molecular [(L)MSiH3]n that can be isolated in soluble form and fully characterized.
Burden of comorbidities is higher among elderly survivors of oropharyngeal cancer compared with controls
Authors: Bigelow Elaine O. , Blackford Amanda L. , Eytan Danielle F. , Eisele David W. , Fakhry Carole 
Published: January 2020

BackgroundThe prevalence of survivors of oropharyngeal cancer (OPC) is increasing due to improved survival for individuals with human papillomavirus (HPV)–related disease. Although elderly survivors of OPC are known to have a high burden of comorbidities, to the authors' knowledge it is unknown how this compares with a similar cohort without a history of cancer.MethodsThe current retrospective, cross‐sectional study included individuals with a first incident primary diagnosis of OPC from 2004 through 2011 from the Surveillance, Epidemiology, and End Results (SEER)–Medicare‐linked databases and matched controls. The baseline prevalence and subsequent incidence of comorbid conditions were identified. The association between comorbidity and overall survival was evaluated.ResultsA total of 2497 eligible patients with OPC were matched to 4994 noncancer controls. Baseline comorbidity was higher in cases (Charlson Comorbidity Index >0 for 48.5% of cases vs 35.8% of controls). At 5 years, cases were more likely than controls to develop comorbidities. Survivors of OPC were at high risk (≥20% cumulative prevalence by 5 years) of developing several comorbidities, including cardiovascular diseases, cerebrovascular disease, chronic obstructive pulmonary disease, and tobacco abuse, and were at moderately high risk (10%‐19% cumulative prevalence) of developing other conditions including carotid artery occlusive stroke, alcohol abuse, depression, and anxiety. In both cases and controls, the presence of the majority of comorbidities either at the time of diagnosis or during the follow‐up period was associated with worse survival.ConclusionsPatients with OPC have a higher comorbidity burden compared with matched controls, both at baseline and during survivorship, the majority of which are associated with decreased survival. Oncologic surveillance of survivors of OPC should include screening for highly prevalent conditions.
Probing Viscosity of Co‐Polymer Hydrogel and HeLa Cell Using Fluorescent Gold Nanoclusters: Fluorescence Correlation Spectroscopy and Anisotropy Decay
Authors: Chakraborty Subhajit , Nandi Somen , Bhattacharyya Kankan , Mukherjee Saptarshi 
Published: January 2020

AbstractFluorescence dynamics of gold nanoclusters (Au9 and Au25) are studied in the complex and crowded environment of a triblock co‐polymer (F127) hydrogel and inside cervical cancer cell, HeLa. In the hydrogel, spherical micelles of F127 remain immobilized with a hydrophobic core (PPO) and a hydrophilic corona (PEO) region. The fluorescence anisotropy decay suggests that the timescale of rotational relaxation in the hydrogel is similar to that in bulk water (viscosity ∼1 cP). From fluorescence correlation spectroscopy (FCS) it is inferred that the local viscosity in the hydrogel is 12 cP for Au9 and 18 cP for Au23. These results indicate that gold nanoclusters (AuNCs) localize in the corona region of the hydrogel. Evidently, frictions against rotation and translation are different inside the gel. It is suggested that rotation of the AuNCs senses the immediate water‐like “void” region while translation motion involves in‐and‐out movement of the AuNCs at the periphery of the gel. Finally, the gold nanoclusters are used for cell imaging and estimation of intracellular viscosity of HeLa cells.
Burst‐aware virtual machine migration for improving performance in the cloud
Authors: Rahmani Somayeh , Khajehvand Vahid 
Published: January 2020

SummaryBurst is a common pattern in the user's requirements, which suddenly increases the workload of virtual machines (VMs) and reduces the performance and energy efficiency of cloud computing systems (CCS). Virtualization technology with the ability to migrate VMs attempts to solve this problem. By migration, VMs can be dynamically consolidated to the users' requests. Burst temporarily increases the workload. Ignoring this issue will lead to incorrect decisions regarding the migration of VMs. It increases the number of migrations and Service Level Agreement Violations (SLAVs) due to overload. This may cause waste of resources, increase in energy consumption, and misplaced VMs. Therefore, a burst‐aware method for these issues is proposed in this paper. The method consists of two algorithms: one for determining the migration time and the other for the placement of VMs. We use the PlanetLab real dataset and CloudSim simulator to evaluate the performance of the proposed method. The results confirm the advantages of the method regarding performance compared to benchmark methods.
Postintroduction evolution contributes to the successful invasion of Chromolaena odorata
Authors: Li Weitao , Zheng Yulong , Zhang Likun , Lei Yanbao , Li Yangping , Liao Zhiyong , Li Zhongpei , Feng Yulong 
Published: January 2020

Abstract

The evolution of increased competitive ability (EICA) hypothesis states that, when introduced in a novel habitat, invasive species may reallocate resources from costly quantitative defense mechanisms against enemies to dispersal and reproduction; meanwhile, the refinement of EICA suggests that concentrations of toxins used for qualitative defense against generalist herbivores may increase. Previous studies considered that only few genotypes were introduced to the new range, whereas most studies to test the EICA (or the refinement of EICA) hypotheses did not consider founder effects.

In this study, genetic and phenotypic data of Chromolaena odorata populations sampled across native and introduced ranges were combined to investigate the role of postintroduction evolution in the successful invasion of C. odorata.

Compared with native populations, the introduced populations exhibited lower levels of genetic diversity. Moreover, different founder effects events were interpreted as the main cause of the genetic structure observed in introduced ranges. Three Florida, two Trinidad, and two Puerto Rico populations may have been the sources of the invasive C. odorata in Asia.

When in free of competition conditions, C. odorata plants from introduced ranges perform better than those from native ranges at high nutrient supply but not at low nutrient level. The differences in performance due to competition were significantly greater for C. odorata plants from the native range than those from the introduced range at both nutrient levels. Moreover, the differences in performance by competition were significantly greater for putative source populations than for invasive populations.

Quantities of three types of secondary compounds in leaves of invasive C. odorata populations were significantly higher than those in putative source populations. These results provide more accurate evidence that the competitive ability of the introduced C. odorata is increased with postintroduction evolution.
Trait–environment interactions affect plant establishment success during restoration
Authors: Zirbel Chad R. , Brudvig Lars A. 
Published: January 2020

AbstractEstablishment and persistence are central to community assembly and are determined by how traits interact with the environment to determine performance (trait–environment interactions). Community assembly studies have rarely considered such trait–environment interactions, however, which can lead to incorrect inferences about how traits affect assembly. We evaluated how functional traits, environmental conditions, and trait–environment interactions structure plant establishment, as a measure of performance. Within 12 prairie restorations created by sowing 70 species, we quantified environmental conditions and counted individuals of each seeded species to quantify first‐year establishment. Three trait–environment interactions structured establishment. Leaf nitrogen interacted with herbivore pressure, as low leaf nitrogen species established relatively better under higher herbivory than species with high leaf nitrogen. Soil moisture interacted with root mass fraction (RMF), with low‐RMF species establishing better with low soil moisture and higher‐RMF species better on wetter soils. Specific leaf area (SLA) interacted with light availability, as low‐SLA species established better under high light conditions and high‐SLA species under low light conditions. Our work illustrates how community assembly can be better described by trait–environment interactions than correlating traits or environment with performance. This knowledge can assist species selection to maximize restoration success.
Feasibility of a Nano‐Carbon Black Paste Electrode for Simultaneous Voltammetric Determination of Antioxidants in Food Samples and Biodiesel in the Presence of Surfactant
Authors: Nunes Angelis Pedro , de Cássia Mendonça Jhessica , Rianne da Rocha Luana , Boareto Capelari Tainara , Carolyne Prete Maiyara , Gava Segatelli Mariana , Borsato Dionisio , Ricardo Teixeira Tarley César 
Published: January 2020

AbstractIn this work, a simple and low‐cost method was developed for the simultaneous determination of the antioxidants tert‐butylhydroquinone (TBHQ) and butylated hydroxyanisole (BHA) in the presence of the cationic surfactant CPB by square wave voltammetry (SWV) technique using a carbon black paste electrode (CBPE). The performance of the method was investigated by varying parameters such as pH, electrolyte, and type and concentration of surfactant. Under the optimum conditions of 0.2 mol L−1 phosphate buffer (pH 7.0), 600.0 μmol L−1 of cetylpyridinium bromide surfactant and SWV operating parameters optimized through the Doehlert matrix, the method presented low limits of quantification for TBHQ and BHA (0.23 and 0.26 μmol L−1, respectively) and high precision in successive measurements. The proposed method was applied in mayonnaise, margarine and biodiesel and the accuracy of method was checked by the HPLC technique.
Single bubble rising behaviors in Newtonian and non‐Newtonian fluids with validation of empirical correlations: A computational fluid dynamics study
Authors: Islam Md. Tariqul , Ganesan Poo Balan , Cheng Ji , Uddin Mohammad Salah 
Published: January 2020

AbstractThe bubble rising (BR) dynamic is a common phenomenon in numerous processes of industries. Here, a single air BR behavior is studied using computational fluid dynamics (CFD) modelling in a Newtonian fluid (NF) and non‐Newtonian fluid (nNF). The volume of fluid formulation with the continuum surface force equation is used to track the air bubble in a NF, while the viscosity of the nNF fluid is estimated by using the power‐law equation. The bubble terminal velocity and its shape deformation, as well as the influence of different dimensionless numbers on BR characterization are investigated. The bubble rise in NF, the bubble terminal velocity increases with decreasing Morton number, and bubble moves up in a zigzag way with shape oscillation for the case of low Morton number of the NF. The bubble rise in nNF, the bubble terminal velocity increases with the increases in the rheological index, and bubble size as well as its shape transforms from an ellipsoidal to ellipsoidal cap types. It is found that the drag coefficient is high in a low rheological index compared with the high rheological index. The CFD results are compared with experimental results and empirical correlations reported in the literature. Good agreements are found between the CFD and the literature data for both fluids.
Effect of cyclic heat treatment process on the pitting corrosion resistance of EN‐1.4405 martensitic, EN‐1.4404 austenitic, and EN‐1.4539 austenitic stainless steels in chloride‐sulfate solution
Authors: Loto Roland Tolulope 
Published: January 2020

AbstractThe effect of high temperature variation on the corrosion resistance of EN‐1.4405, EN‐1.4404, and EN‐1.4539 stainless steels in 2 M H2SO4/3.5% NaCl solution was studied. Untreated EN 1.4405 exhibited the highest corrosion rate at 4.775 mm/year compared to untreated EN 1.4539 with the lowest corrosion rate (1.043 mm/year). Repetitive heat treatment significantly decreased the corrosion rate of the steels by 54.61%, 27.83%, and 50.28% to 2.167, 1.396, and 0.519 mm/year. EN‐1.4539 steel exhibited the shortest metastable pitting activity among the untreated steels due to higher resistance to transient pit formation while heat treated EN‐1.4404 and EN‐1.4539 steels exhibited double metastable pitting activity. Heat treated EN‐1.4405 was unable to passivate after anodic polarization signifying weak corrosion resistance. Pitting current of heat‐treated steels was generally higher than the untreated counterparts. Heat treatment extended the passivation range value of EN‐1.4405 and EN‐1.4539 steels compared to those of the untreated steels. The corrosion potential of heat‐treated steels significantly shifted to electronegative values. The optical image of untreated and heat treated EN‐1.4404 and EN‐1.4539 steels were generally similar while the images for EN‐1.4405 significantly contrast each other.
Boundary condition control of fluvial obstacle mark formation – framework from a geoscientific perspective
Authors: Schlömer Oliver , Herget Jürgen , Euler Thomas 
Published: January 2020

ABSTRACTObstacle marks are sedimentary bedforms, typically composed of an upstream local scour hole and a downstream sediment accumulation in the vicinity of an obstruction that is exposed to a current. However, specific morphologies are variable in fluvial, coastal and submarine environments. Although obstacle marks and the phenomenon of local scouring are subject to different scientific disciplines, the objectives of investigations are rather incoherent and no systematic framework for analysing and evaluating boundary condition control exists yet, especially concerning limited knowledge of the cause and effect relationship of obstacle mark formation at instream boulders or vegetation elements in variable environmental conditions. Thus, a parameter framework is developed which identifies a spectrum of extrinsic and intrinsic boundary conditions that control the major process dynamics of obstacle mark formation. The framework is composed of dimensionless control parameters that are separated by a hierarchical order regarding their significance for obstacle mark formation. Primary control parameters determine the geometrical scale of flow field at the obstacle, and therefore control the potential maximum size of the obstacle. Secondary control parameters affect the dynamics of the flow field in geometrical scale and limit the potential maximum size of the emerging sedimentary structure if thresholds are crossed. The framework is supposed to be a foundation for subsequent quantification and determination of thresholds by systematic laboratory studies. To elucidate this, flume‐based research is presented, evaluating the influence of different flow levels at boulder‐like obstacles of different shapes. The results show that obstacle mark dimensions were maximized at shallow flow depths compared to obstacle dimensions, while deep flows at submerged boulder‐like obstructions caused considerably smaller obstacle marks. In interdependency with a rounded and more streamlined obstacle shape, deep flows even cause a deviation of morphology if the flow depth above an obstacle exceeds 1.6 times the obstacle's dimensions. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd.
Data poisoning attacks on neighborhood‐based recommender systems
Authors: Chen Liang , Xu Yangjun , Xie Fenfang , Huang Min , Zheng Zibin 
Published: January 2020

AbstractNowadays, collaborative filtering recommender systems have been widely deployed in many commercial companies to make profit. Neighborhood‐based collaborative filtering (CF) is common and effective. To date, despite its effectiveness, there has been little effort to explore their robustness and the impact of data poisoning attacks on their performance. Can the neighborhood‐based recommender systems be easily fooled? To this end, we shed light on the robustness of neighborhood‐based recommender systems and propose a novel data poisoning attack framework, encoding the purpose of attack and constraint against them. We first illustrate how to calculate the optimal data poisoning attack, namely, UNAttack. We inject a few well‐designed fake users into the recommender systems such that target items will be recommended to as many normal users as possible. Extensive experiments are conducted on three real‐world datasets to validate the effectiveness and the transferability of our proposed method. In addition, some interesting phenomena can be found. For example, (i) neighborhood‐based recommender systems with Euclidean distance‐based similarity have strong robustness and (ii) the fake users can be transferred to attack the state‐of‐the‐art CF recommender systems such as neural CF and Bayesian personalized ranking matrix factorization.
Basic taste characteristics of flavor material from cultured Takifugu obscurus by‐products
Authors: Liao Ya , Wang Wenli , Chen Gaole , Zhang Ninglong , Liu Yuan 
Published: January 2020

AbstractTakifugu obscurus (T. obscurus) by‐products (fish heads and bones) account for about 35% of total weight. In order to improve its availability, flavor materials based on T. obscurus by‐product have been developed through enzymatic hydrolysis and Maillard thermal reaction. However, their basic taste characteristics have not been extensively investigated. In this study, the taste intensities of T. obscurus flavor materials (protein hydrolysates and Maillard reaction products) at different concentrations, pH, and temperatures were compared and distinguished by sensory evaluation combined with electronic tongue analysis. Results showed that T. obscurus by‐products protein hydrolysates (TBPH) had the optimal taste intensities (mainly umami taste) at 5.0 g/L, pH 6.5, and Maillard reaction products (MRPs) were at 4.0 g/L, pH 7.0. They both possessed excellent thermal stability, and their recognition thresholds were 0.08 g/100 mL for TBPH and 0.03 g/100 mL for MRPs, respectively. This study would lay a theoretical foundation to understand the basic flavor characteristics of T. obscurus by‐products.