bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterolytic Si−H Bond Cleavage at a Molybdenum‐Oxido‐Based Lewis Pair
Authors: Zwettler Niklas , Walg Simon P. , Belaj Ferdinand , Mösch‐Zanetti Nadia C. 
Published: March 2018

AbstractThe reaction of a molybdenum(VI) oxido imido complex with the strong Lewis acid B(C6F5)3 gave access to the Lewis adduct [Mo{OB(C6F5)3}(NtBu)L2] featuring reversible B−O bonding in solution. The resulting frustrated Lewis pair (FLP)‐like reactivity is reflected by the compound's ability to heterolytically cleave Si−H bonds, leading to a clean formation of the novel cationic MoVI species 3 a (R=Et) and 3 b (R=Ph) of the general formula [Mo(OSiR3)(NtBu)L2][HB(C6F5)3]. These compounds possess properties highly unusual for molybdenum d0 species such as an intensive, charge‐transfer‐based color as well as a reversible redox couple at very low potentials, both dependent on the silane used. Single‐crystal X‐ray diffraction analyses of 2 and 4 b, a derivative of 3 b featuring the [FB(C6F5)3]− anion, picture the stepwise elongation of the Mo=O bond, leading to a large increase in the electrophilicity of the metal center. The reaction of 3 a and 3 b with benzaldehyde allowed for the regeneration of compound 2 by hydrosilylation of the benzaldehyde. NMR spectroscopy suggested an unusual mechanism for the transformation, involving a substrate insertion in the B−H bond of the borohydride anion.
Green synthesis of copper oxide nanoparticles impregnated on activated carbon using Moringa oleifera leaves extract for the removal of nitrates from water
Authors: Galan Crislaine Rodrigues , Silva Marcela Fernandes , Mantovani Daniel , Bergamasco Rosângela , Vieira Marcelo Fernandes 
Published: March 2018

AbstractThe present work aims at impregnating copper oxide nanoparticles (Cu NPs) on activated carbon by means of green synthesis with Moringa oleifera leaf extract to develop a material to remove contaminants from water. The produced materials were characterized by means of their textural (specific surface area), morphological (Transmission Electron Microscopy), and structural (X‐ray Diffraction) properties. Particles size was estimated by Scherrer equation and the elemental copper concentrations were estimated by Total Reflection X‐ray Fluorescence (TXRF). Adsorption experiments, as well as pH, kinetics, and adsorption isotherms studies were carried out with the intent of evaluating the efficiency of nitrate (NO3‐) removal from water. The impregnation efficiency of Cu NPs on activated carbon after the adsorption process was measured by means of TXRF analyses. Characterization results confirmed the formation, impregnation, and stability of copper oxide nanoparticles supported on activated carbon, whose crystallite average size ranged between 6 and 61 nm. The proposed method for the nanoparticles synthesis and impregnation were demonstrated to be simple and eco‐friendly. Impregnated carbons presented significant nitrate removal (about 60 %) thus indicating their potential application in water treatment.
Data‐driven flotation reagent changing evaluation via union distribution analysis of bubble size and shape
Authors: Ai Mingxi , Xie Yongfang , Xu Degang , Gui Weihua , Yang Chunhua 
Published: March 2018

AbstractDue to the frequent fluctuation of the ore grade and other random disturbances in the flotation process, reagents need to be changed in real time to achieve desired metallurgical parameters. To avoid erratic operation, a data‐driven reagent evaluation model was proposed. It is insensitive for bubble size distribution to differentiate froth surface images with a similar average bubble size but different grade. Since bubble shape is heavily influenced by froth grade, and bubble deformation is positively correlated to the froth grade in industry, a novel froth image feature named the union distribution of bubble size and shape was developed. Then, a multi‐output least square support vector regressor was introduced to develop a dynamic causal model to simulate the relationship between the reagents and the produced future froth surface appearance feature. Next, the health status of the reagents is rated by recognizing the category of predicted future froth. Under guidance from this reagent evaluation model, the rationality of reagent dosages can be obtained in priority. The proposed method was applied in a gold‐antimony flotation plant located in Hunan, China. It improved the efficiency of froth flotation and reduced false reagent operation.
Asymmetric Transfer and Pressure Hydrogenation with Earth‐Abundant Transition Metal Catalysts
Authors: Zhang Zhenfeng , Butt Nicholas Andrew , Zhou Muxing , Liu Delong , Zhang Wanbin 
Published: March 2018

AbstractThe asymmetric transfer and pressure hydrogenation of various unsaturated substrates provides a succinct pathway to important chiral intermediates and products such as chiral alcohols, amines, and alkanes. The use of earth‐abundant transition metals such as Fe, Co, Ni, and Cu in hydrogenation reactions provides an attractive alternative to traditionally used metals such as Ru, Rh, Ir, and Pd because they are comparatively inexpensive, less toxic, and as their name suggests, more abundant in nature. Earth‐abundant transition metal‐catalyzed asymmetric hydrogenation is rapidly becoming an important area of research. This review summarizes advances in the asymmetric hydrogenation of unsaturated bonds (ketones, imines, and alkenes) with earth‐abundant transition metals.
Sustained sex‐based treatment differences in acute coronary syndrome care: Insights from the American Heart Association Get With The Guidelines Coronary Artery Disease Registry
Authors: Udell Jacob A. , Fonarow Gregg C. , Maddox Thomas M. , Cannon Christopher P. , Frank Peacock W. , Laskey Warren K. , Grau‐Sepulveda Maria V. , Smith Eric E. , Hernandez Adrian F. , Peterson Eric D. , Bhatt Deepak L. ,   for the Get With The Guidelines Steering Committee and Investigators
Published: March 2018

BackgroundSex‐based differences in acute coronary syndrome (ACS) mortality may attenuate with age due to better symptom recognition and prompt care.HypothesisAge is a modifier of temporal trends in sex‐based differences in ACS care.MethodsAmong 104 817 eligible patients with ACS enrolled in the AHA Get With the Guidelines–Coronary Artery Disease registry between 2003 and 2008, care and in‐hospital mortality were evaluated stratified by sex and age. Temporal trends within sex and age groups were assessed for 2 care processes: percentage of STEMI patients presenting to PCI‐capable hospitals with a DTB time ≤ 90 minutes (DTB90) and proportion of eligible ACS patients receiving aspirin within 24 hours.ResultsAfter adjustment for clinical risk factors and sociodemographic and hospital characteristics, 2276 (51.7%) women and 6276 (56.9%) men with STEMI were treated with DTB90 (adjusted OR: 0.85, 95% CI: 0.80–0.91, P < 0.0001 for women vs men). Time trend analysis showed an absolute increase ranging from 24% to 35% in DTB90 rates among both men and women (P for trend <0.0001 for each group), with consistent differences over time across the 4 age/sex groups (3‐way P‐interaction = 0.93). Despite high rate of baseline aspirin use (87%–91%), there was a 9% to 11% absolute increase in aspirin use over time, also with consistent differences across the 4 age/sex groups (all 3‐way P‐interaction ≥0.15).ConclusionsSubstantial gains of generally similar magnitude existed in ACS performance measures over 6 years of study across sex and age groups; areas for improvement remain, particularly among younger women.
Regional chemoarchitecture of the brain of lungfishes based on calbindin D‐28K and calretinin immunohistochemistry
Authors: Morona Ruth , López Jesús M. , Northcutt R. Glenn , González Agustín 
Published: March 2018

AbstractLungfishes are the closest living relatives of land vertebrates, and their neuroanatomical organization is particularly relevant for deducing the neural traits that have been conserved, modified, or lost with the transition from fishes to land vertebrates. The immunohistochemical localization of calbindin (CB) and calretinin (CR) provides a powerful method for discerning segregated neuronal populations, fiber tracts, and neuropils and is here applied to the brains ofNeoceratodusandProtopterus, representing the two extant orders of lungfishes. The results showed abundant cells containing these proteins in pallial and subpallial telencephalic regions, with particular distinct distribution in the basal ganglia, amygdaloid complex, and septum. Similarly, the distribution of CB and CR containing cells supports the division of the hypothalamus of lungfishes into neuromeric regions, as in tetrapods. The dense concentrations of CB and CR positive cells and fibers highlight the extent of the thalamus. As in other vertebrates, the optic tectum is characterized by numerous CB positive cells and fibers and smaller numbers of CR cells. The so‐called cerebellar nucleus contains abundant CB and CR cells with long ascending axons, which raises the possibility that it could be homologized to the secondary gustatory nucleus of other vertebrates. The corpus of the cerebellum is devoid of CB and CR and cells positive for both proteins are found in the cerebellar auricles and the octavolateralis nuclei. Comparison with other vertebrates reveals that lungfishes share most of their features of calcium binding protein distribution with amphibians, particularly with salamanders.
Frequency‐dependent anisotropic modeling and analysis using mfEIT: A computer simulation study
Authors: Zhang Tingting , Li Rihui , Potter Thomas , Seo Jin Keun , Li Guanglin , Zhang Yingchun 
Published: March 2018

AbstractElectrical properties of human tissues are usually linked with structure of thin insulating membranes and thereby reflect physiological function of the tissues or organs. It is clinically important to characterize electrical properties of tissues in vivo. Electrical impedance tomography is a recently developed medical imaging technique, which has been exploited to characterize electrical properties (conductivity and permittivity) of human tissues by injecting currents and measuring the resulting voltages at boundary electrodes. The electrical characteristic of a majority of human tissues, such as bones, muscles, and brain white matter, exhibits an anisotropic property. The anisotropic phenomenon of human tissues is frequency dependent that vanishes at high frequencies. Previous electrical impedance tomography studies that aimed at the reconstruction of anisotropic subject tissues have been focused on the theoretical analysis of uniqueness up to a diffeomorphism or the establishment of an accurate forward model by using an anisotropic conductivity tensor. However, effects of the current frequency on the accuracy of the reconstructions of anisotropic subjects remain poorly studied. The goal of this study is to examine the feasibility of multifrequency electrical impedance tomography by using it in a simulation study to recover the frequency‐dependent anisotropic properties of a phantom subject composed of alternating insulating and conductive layers. The anisotropic properties of the subject were analyzed by an effective admittivity tensor, and the responses of the current flow pathways and voltages were investigated at various applied current frequencies in the forward model. The linear reconstruction was performed following the sensitivity matrix approach at multiple frequencies. Simulation results achieved at various frequencies revealed that the anisotropy of the model was effectively reconstructed at low frequencies and disappeared at high frequencies, from which we validated the feasibility of multifrequency electrical impedance tomography method in reconstructing the anisotropic directions of the considered object.
A computational modeling of blood flow in asymmetrically bifurcating microvessels and its experimental validation
Authors: Lee Tae‐Rin , Hong Ji‐Ah , Yoo Sung Sic , Kim Do Wan 
Published: March 2018

AbstractMicrovascular transport is complex due to its heterogeneity. Many researchers have been developing mathematical and computational models in predicting microvascular geometries and blood transport. However, previous works were focused on developing simulation models, not on validating suggested models with microvascular geometry and blood flow in the real microvasculature. In this paper, we suggest a computational model for microvascular transport with experimental validation in its geometry and blood flow. The geometry is generated by controlling asymmetric conditions of microvascular network. Also, the blood flow in microvascular networks is predicted by considering in vivo viscosity, Poiseuille flow model, and hematocrit redistribution by plasma skimming. The suggested model is validated by the measured data in rat mesentery. Also, the microvascular transport in a case of mouse cortex is predicted and compared against experimental data to check applicability of the suggested model.
Efficient estimation of personalized biventricular mechanical function employing gradient‐based optimization
Authors: Finsberg Henrik , Xi Ce , Tan Ju Le , Zhong Liang , Genet Martin , Sundnes Joakim , Lee Lik Chuan , Wall Samuel T. 
Published: March 2018

AbstractIndividually personalized computational models of heart mechanics can be used to estimate important physiological and clinically‐relevant quantities that are difficult, if not impossible, to directly measure in the beating heart. Here, we present a novel and efficient framework for creating patient‐specific biventricular models using a gradient‐based data assimilation method for evaluating regional myocardial contractility and estimating myofiber stress. These simulations can be performed on a regular laptop in less than 2 h and produce excellent fit between measured and simulated volume and strain data through the entire cardiac cycle. By applying the framework using data obtained from 3 healthy human biventricles, we extracted clinically important quantities as well as explored the role of fiber angles on heart function. Our results show that steep fiber angles at the endocardium and epicardium are required to produce simulated motion compatible with measured strain and volume data. We also find that the contraction and subsequent systolic stresses in the right ventricle are significantly lower than that in the left ventricle. Variability of the estimated quantities with respect to both patient data and modeling choices are also found to be low. Because of its high efficiency, this framework may be applicable to modeling of patient specific cardiac mechanics for diagnostic purposes.
Study of color perceptibility of gonio‐apparent panels with curvature angle
Authors: Chorro Elísabet , Perales Esther , Viqueira Valentín , Martínez‐Verdú Francisco M. 
Published: March 2018

AbstractColor tolerances of curved gonio‐apparent panels have been studied in this work. To achieve that, an experimental set‐up of the illumination and tilt variation of two identical coated panels was designed for simulation of curved panels with both concave and convex borders and with and without effect pigments (perceived as solid and gonio‐apparent colors, respectively). Finally, visual and instrumental measures were collected with both curvatures. The results show that the relationship of the instrumental color difference with the tilt angle can be modeled by a second‐order and the vertex did not depend on illumination, but on coating type. The critical angles (the angle marked when the color discrepancy between two identical samples is merely perceived) assessed by the observers showed that they were not equal according to border, nor according to coating type. The color tolerances at these angles were clearly higher than the conventional chromatic thresholds of industrial color comparisons.
Synthesis of Zeolite W from Potassic Rocks Activated by KOH Sub‐molten Salt Method
Authors: Meng Yanrui , Zhao Bin , Zhang Hongqi , Liu Xiuwu , Cao Jilin 
Published: March 2018

AbstractPotassic rocks are decomposed to active amorphous material via KOH sub‐molten salt method. Zeolite W is successfully synthesized using amorphous precursor from potassic rocks as raw material. Effects of reaction temperature, reaction time, mass concentration of KOH and mass ratio of KOH‐to‐ore on the decomposition of potassic rocks are investigated. X‐ray powder diffraction (XRD) is used to characterize the precursors and as‐prepared zeolites. The results indicate that the active amorphous precursor is obtained in KOH sub‐molten salt medium with 75% alkali mass concentration and an alkali‐to‐ore mass ratio of 3.5:1 at 200 °C for 7 h. The exchange capacities of modified zeolite W in KCl solution and simulated seawater are 156.8 mgK+/g and 38.39 mgK+/g, respectively. After synthesis of zeolite W, the mother liquor can be recycled.
Corporate Social Responsibility and Firm Idiosyncratic Risk in Different Market States
Authors: Chen Roger C.Y. , Hung Shih‐Wei , Lee Chen‐Hsun 
Published: March 2018

AbstractThis study explored the influence of corporate social responsibility (CSR) on idiosyncratic risk. Referring to an approach used by Pagan and Sossounov, we separated the sample period into up‐market, down‐market, and correction conditions and observed the changes in the influence of CSR on idiosyncratic risk in different market states. The results find that firms with better CSR performance can reduce their idiosyncratic risk. Furthermore, in different market states, CSR can significantly decrease idiosyncratic risk, whereas firms with poorer CSR performance have more idiosyncratic risk. Our findings are beneficial for firms that can use CSR engagement to adjust their business strategy and reduce operational uncertainty. Therefore, CSR engagement can function as a tool for risk management. Copyright © 2018 John Wiley & Sons, Ltd and ERP Environment
Environmental policy disclosures and sustainable development: Determinants, measure and impact on firm value for ADX listed companies
Authors: Kolsi Mohamed Chakib , Attayah Osama F 
Published: March 2018

AbstractCorporate social responsibility (CSR) disclosures have gained great attention in both the media and the academic community for many decades. In this paper, we shed light on three aspects of CSR disclosures, namely the determinants, measure and impact on firm value. Using a sample of 61 firms listed on the ADX for the period 2010–2014 and computing an eight‐item index, our results are conclusive and show that listing history, governmental sector, board size, financial leverage and firm size have a positive impact on CSR disclosures. By contrast, firm profitability, industrial sector and ownership concentration have no impact on the extent of CSR disclosures. Finally, CSR disclosures have no impact on firm value as proxied by market‐to‐book ratio. Our results remain unchanged using additional robustness checks. Our study highlights the three aspects of social disclosures (i.e. determinants, measure and impact) in an emerging stock market (ADX). Our findings will help investors when assessing firm value and policy makers when issuing CSR disclosure rules.
A Hybrid Mineral Battery: Energy Storage and Dissolution Behavior of CuFeS2 in a Fixed Bed Flow Cell
Authors: Deen Kashif Mairaj , Asselin Edouard 
Published: March 2018

AbstractThe development of a hybrid system capable of storing energy and the additional benefit of Cu extraction is discussed in this work. A fixed bed flow cell (FBFC) was used in which a composite negative electrode containing CuFeS2 (80 wt %) and carbon black (20 wt %) in graphite felt was separated from a positive (graphite felt) electrode by a proton‐exchange membrane. The anolyte (0.2 m H2SO4) and catholyte (0.5 m Fe2+ in 0.2 m H2SO4 with or without 0.1 m Cu2+) were circulated in the cell. The electrochemical activity of the Fe2+/Fe3+ redox couple over graphite felt significantly improved after the addition of Cu2+ in the catholyte. Ultimately, in the CuFeS2∥Fe2+/Cu2+ (CFeCu) FBFC system, the specific capacity increased continuously to 26.4 mAh g−1 in 500 galvanostatic charge–discharge (GCD) cycles, compared to the CuFeS2∥Fe2+ (CFe) system (13.9 mAh g−1). Interestingly, the specific discharge energy gradually increased to 3.6 Wh kg−1 in 500 GCD cycles for the CFeCu system compared to 3.29 Wh kg−1 for the CFe system in 150 cycles. In addition to energy storage, 10.75 % Cu was also extracted from the mineral, which is an important feature of the CFeCu system as it would allow Cu extraction and recovery through hydrometallurgical methods.
FMD: A DoS mitigation scheme based on flow migration in software‐defined networking
Authors: Wu Pengpeng , Yao Lin , Lin Chi , Wu Guowei , Obaidat Mohammad S. 
Published: March 2018

SummarySoftware‐defined networking (SDN) emerges as the next generation of networking architecture, aiming to improve the network manageability and adaptability. However, because of the centralized control policy, SDN is liable to suffering from the denial of service attack in both the data plane and the control plane. To resist the attack and prevent the network from being paralyzed, we propose a novel mitigation scheme named flow migration defense, which uses a slave controller as a substitution to endure flooding requests mitigated from the master controller. Considering the special case that the normal requests may be regarded as the malicious ones, these requests are reforwarded back to the master controller on the basis of the round‐robin scheduling. To prevent the master controller from being flooded by the reforwarded requests, we design the adaptive rate adjustment method to adjust the reforwarding rate. Compared with multilevel feedback queue and FloodDefender, simulations demonstrate that flow migration defense can mitigate the SDN‐aimed denial of service attack efficiently with a better performance in terms of request response time, packet loss rate, and mitigation time.
Adaptive video streaming testbed design for performance study and assessment of QoE
Authors: Taha Miran , Lloret Jaime , Ali Aree , Garcia Laura 
Published: March 2018

SummaryHypertext Transfer Protocol adaptive streaming switches between different video qualities, adapting to the network conditions, and avoids stalling streamed frames over high‐oscillation client's throughput improving the users' quality of experience (QoE). Quality of experience has become the most important parameter to lead the service providers to know about the end‐user feedback. Implementing Hypertext Transfer Protocol adaptive streaming applications to find out QoE in real‐life scenarios of vast networks becomes more challenging and complex task regarding to cost, agile, time, and decisions. In this paper, a virtualized network testbed to virtualize various machines to support implementing experiments of adaptive video streaming has been developed. Within the test study, the metrics which demonstrate performance of QoE are investigated, respectively, including initial delay (ie, startup delay at the beginning of playback a video), frequency switches (ie, number of times the quality is changed), accumulative video time (ie, number and length of stalls), CPU usage, and battery energy consumption. Furthermore, the relation between effective parameters of QoS on the aforementioned metrics for different segment length is investigated. Experimental results show that the proposed virtualized system is agile, easy to install and use, and costs less than real testbeds. Moreover, the subjective and objective performance studies of QoE evaluation in the system have proven that the segment lengths of 6 to 8 seconds were faired and more efficient than others according to the investigated parameters.