bluuebunny/crossref_metadata_2025_split huggingface dataset:
Triarylamine‐Cored Dendritic Molecular Gel for Efficient Colorometric, Fluorometric, and Impedometeric Detection of Picric Acid
Authors: Mondal Sanjoy , Bairi Partha , Das Sujoy , Nandi Arun K. 
Published: February 2018

AbstractDetection of nitroaromatics at ultralow concentration is a major security concern in defense, forensics, and environmental science. To this end, a new triarylamine‐cored dendritic gelator (OGR) was synthesized, which produced thermoreversible, thixotropic, and fluorescent gels in n‐octanol. On gelation, both π–π* transitions and the emission peak of the gelator show redshifts with a 4.5‐fold increase of fluorescence intensity in the gel state indicating J‐aggregation. The nitrogen lone‐pair electrons of OGR make it a donor, and electron transfer occurs to acceptor nitroaromatics causing fluorescence quenching, which is further promoted due to its acidity. The Stern–Volmer rate constants measured for different nitroaromatics showed that it senses picric acid (PA) best. The contact‐mode technique with OGR‐treated paper strips can allow naked‐eye detection of PA under UV light down to 10−11 m concentration within 30 s. Reusability of the gel is achieved by treating OGR@PAx with NaOH solution. Impedance spectroscopic results indicated a decrease of both charge‐transport resistance and Warburg impedance on successive addition of PA. The limits of detection of PA determined from fluorescence and impedance measurements match well. Thus, the OGR gel is a reusable, low‐cost, specific sensor for PA by naked‐eye colorimetric, fluorescence, and impedance techniques.
Fast and Selective Heavy Metal Removal by a Novel Metal‐Organic Framework Designed with In‐Situ Ligand Building Block Fabrication Bearing Free Nitrogen
Authors: Rouhani Farzaneh , Morsali Ali 
Published: February 2018

AbstractFast and effective adsorbents for the selective removal of HgII and PbII ions were prepared by the reaction of Zn(NO3)2⋅6H2O, H2BDC, and N1,N2‐bis(pyridin‐4‐ylmethylene) ethane‐1,2‐diamine (L) that yields an unprecedented two‐dimensional layer‐based supramolecular framework, {Zn(BDC)(L*)}⋅DMF (TMU‐40), by solvothermal reaction. The formation of this framework involved an in situ C=C coupling of L to L* [L*=5,6‐di(pyridin‐4‐yl)‐1,2,3,4‐tetrahydropyrazine]. As L* contains free nitrogen atoms, direct reaction of L* and metals led to metallated products. Post‐synthetic modification of this novel MOF (TMU‐40) with H2O2 gives a new framework (O‐TMU‐40) by same structure and different ligand, which also bears free nitrogen atoms. FTIR spectra, TGA analysis, X‐ray diffraction, Zeta Potential analysis and 1H NMR spectroscopy were used to characterize the prepared frameworks. The TMU‐40 and O‐TMU‐40 frameworks were used for heavy‐metal removal from aqueous solutions. Maximum adsorption values of 269 mg g−1 for HgII with TMU‐40 and 215 mg g−1 for PbII with O‐TMU‐40 were achieved in 10 min at 298 Kwithout changes in the pH of the adsorption medium with pseudo‐second order kinetics based on the Langmuir model. The extremely fast kinetics of TMU‐40 means this adsorbent can reduce heavily contaminated water containing HgII concentrations of 40 ppm down to the acceptable limit of 2 ppb.
Iron Carbides and Nitrides: Ancient Materials with Novel Prospects
Authors: Ye Zhantong , Zhang Peng , Lei Xiang , Wang Xiaobai , Zhao Nan , Yang Hua 
Published: February 2018

AbstractIron carbides and nitrides have aroused great interest in researchers, due to their excellent magnetic properties, good machinability and the particular catalytic activity. Based on these advantages, iron carbides and nitrides can be applied in various areas such as magnetic materials, biomedical, photo‐ and electrocatalysis. In contrast to their simple elemental composition, the synthesis of iron carbides and nitrides still has great challenges, particularly at the nanoscale, but it is usually beneficial to improve performance in corresponding applications. In this review, we introduce the investigations about iron carbides and nitrides, concerning their structure, synthesis strategy and various applications from magnetism to the catalysis. Furthermore, the future prospects are also discussed briefly.
Enantiospecific Three‐Component Alkylation of Furan and Indole
Authors: Silvi Mattia , Schrof Raffael , Noble Adam , Aggarwal Varinder K. 
Published: February 2018

AbstractFuran‐ and indole‐derived boronate complexes react with alkyl iodides under radical (photoredox) or polar (SN2) conditions to generate three‐component alkylation products with high efficiency and complete stereospecificity. The methodology allows the incorporation of versatile functional groups such as nitriles, ketones, esters, sulfones, and amides, providing rapid access to complex chiral heteroaromatic molecules in enantioenriched form. Interestingly, while indolyl boronate complexes react directly with alkyl halides in a polar pathway, furyl boronates require photoredox catalysis. Careful mechanistic analysis revealed that the boronate complex not only serves as a substrate in the reaction but also acts as a reductive quencher for the excited state of the photocatalyst.
The Doctrine of the Mean: Workplace Relationships and Turnover Intention
Authors: Lai Fong‐Yi , Lu Szu‐Chi , Lin Cheng‐Chen , Lee Yu‐Chin 
Published: February 2018

AbstractThe present study examines the curvilinear relationships between LMX/TMX and team members' turnover intention simultaneously. That is, members with high LMX, TMX, or both are more likely to have turnover intention. Hypotheses were tested with a sample of 452 nurses, and we adopted the response surface methodology and polynomial regression to test our theoretical model. The hierarchical regression analysis showed that TMX has a U‐shaped relationship with turnover intention but not with LMX. In addition, the results indicate that both the congruence and incongruence of LMX and TMX result in higher turnover intention, but moderate levels of LMX and TMX have the lowest turnover intention. Strengths, limitations, practical implications, and directions for future research are discussed. Copyright © 2018 ASAC. Published by John Wiley & Sons, Ltd.
Mixing in a co‐current upflow bubble column reactors with and without internals
Authors: Bhusare Vishal H. , Kalaga Dinesh V. , Dhiman Mukesh K. , Joshi Jyestharaj B. , Roy Shantanu 
Published: February 2018

AbstractLiquid phase mixing is a phenomenon that results mainly due to convective and turbulent flow fields, which are generated by hydrodynamic interactions between the gas and liquid phases within a continuous co‐current upflow bubble column reactor. The extent of liquid phase mixing is usually quantified through the mixing time, or the axial dispersion coefficient. In the present work, the computational fluid dynamics (CFD) simulations for mixing and RTD in a continuous bubble column (with and without internals) are performed by using OpenFOAM 2.3.1. The superficial gas velocities were 0.014, 0.088, and 0.221 m/s and the superficial liquid velocities were 0.005 and 0.014 m/s. The simulations have been performed for three different configurations of the bubble column, that is, (a) an open bubble column, (b) a column with one vertical central rod of 36 mm diameter, (c) a column with the same central rod and four vertical additional rods of 12 mm diameter. The effects of superficial gas and liquid velocities and column internals were investigated on liquid phase mixing and the axial dispersion coefficient. Comparisons have been made between the experimental measurements and the CFD simulations.
Multimode processes monitoring based on hierarchical mode division and subspace decomposition
Authors: Li Shuai , Zhou Xiaofeng , Shi Haibo , Pan Fucheng , Li Xin , Zhang Yichi 
Published: February 2018

AbstractTo handle multimodal uncertainty and dynamics which are common in actual industrial processes, this paper proposes a multimode process monitoring method based on hierarchical mode division and subspace decomposition. First, hierarchical mode division is presented to achieve hierarchical mode information for multimode process modelling, which can improve the adaptability of industrial processes with multimodal uncertainty. Then, hierarchical subspace decomposition is presented to decompose multimode processes into multiple global subspaces and multiple local subspaces for monitoring. Lastly, the most similar mode with various hierarchical modes at the current sampling point is dynamically determined for monitoring, which considers multimodal dynamics. The simulation tests of the penicillin fermentation processes are developed to show feasibility and superiority of the proposed method.
A learning‐based approach for virtual machine placement in cloud data centers
Authors: Ghobaei‐Arani Mostafa , Rahmanian Ali Asghar , Shamsi Mahboubeh , Rasouli‐Kenari Abdolreza 
Published: February 2018

SummaryIn recent years, the increasing use of cloud services has led to the growth and importance of developing cloud data centers. One of the challenging issues in the cloud environments is high energy consumption in data centers, which has been ignored in the corporate competition for developing cloud data centers. The most important problems of using large cloud data centers are high energy costs and greenhouse gas emission. So, researchers are now struggling to find an effective approach to decreasing energy consumption in cloud data centers. One of the preferred techniques for reducing energy consumption is the virtual machines (VMs) placement. In this paper, we present a VM allocation algorithm to reduce energy consumption and Service Level Agreement Violation (SLAV). The proposed algorithm is based on best‐fit decreasing algorithm, which uses learning automata theory, correlation coefficient, and ensemble prediction algorithm to make better decisions in VM allocation. The experimental results indicated improvement regarding energy consumption and SLAV, compared with well‐familiar baseline VM allocation algorithms.
Is cortisol production in response to an acute stressor associated with diurnal cortisol production during adolescence?
Authors: Lucas‐Thompson Rachel G. , Henry Kimberly L. , McKernan Charlotte J. 
Published: February 2018

AbstractThe goal of the current study was to examine the extent to which cortisol responding to an acute stressor is related to diurnal cortisol patterns during adolescence. Participants were 105 adolescents (10–17 years of age) who experienced a robust social‐evaluative stressor and provided saliva samples (before and immediately after, as well as 10, 20, and 30 min after the stressor) to assess both cortisol reactivity and recovery and also provided saliva samples (at wake‐up, 30 min after wake‐up, 4 pm, and at bedtime) on two consecutive days to measure diurnal cortisol production. Dual process latent growth curve models, one for cortisol reactivity and one for diurnal cortisol, indicated that dampened cortisol reactivity and prolonged cortisol recovery (i.e., less cortisol produced during reactivity but more cortisol produced during recovery) were associated with dampened decreases in cortisol production across the day, suggesting that adolescents are likely to show attenuation in multiple components of HPA axis functioning.
Cortical thickness patterns as state biomarker of anorexia nervosa
Authors: Lavagnino Luca , Mwangi Benson , Cao Bo , Shott Megan E. , Soares Jair C. , Frank Guido K. W. 
Published: February 2018

AbstractObjectiveOnly few studies have investigated cortical thickness in anorexia nervosa (AN), and it is unclear whether patterns of altered cortical thickness can be identified as biomarkers for AN.MethodCortical thickness was measured in 19 adult women with restricting‐type AN, 24 individuals recovered from restricting‐type AN (REC‐AN) and 24 healthy controls. Those individuals with current or recovered from AN had previously shown altered regional cortical volumes across orbitofrontal cortex and insula. A linear relevance vector machine‐learning algorithm estimated patterns of regional thickness across 24 subdivisions of those regions.ResultsRegion‐based analysis showed higher cortical thickness in AN and REC‐AN, compared to controls, in the right medial orbital (olfactory) sulcus, and greater cortical thickness for short insular gyri in REC‐AN versus controls bilaterally. The machine‐learning algorithm identified a pattern of relatively higher right orbital, right insular and left middle frontal cortical thickness, but lower left orbital, right middle and inferior frontal, and bilateral superior frontal cortical thickness specific to AN versus controls (74% specificity and 74% sensitivity, χ2 p < .004); predicted probabilities differed significantly between AN and controls (p < .023). No pattern significantly distinguished the REC‐AN group from controls.ConclusionsHigher cortical thickness in medial orbitofrontal cortex and insula probably contributes to higher gray matter volume in AN in those regions. The machine‐learning algorithm identified a mixed pattern of mostly higher orbital and insular, but relatively lower superior frontal cortical thickness in individuals with current AN. These novel results suggest that regional cortical thickness patterns could be state markers for AN.
A hidden cost of migration? Innate immune function versus antioxidant defense
Authors: Eikenaar Cas , Isaksson Caroline , Hegemann Arne 
Published: February 2018

AbstractMigration is energetically demanding and physiologically challenging. Migrating birds, for example, need to boost their antioxidant defenses to defeat the pro‐oxidants produced during high energetic activity. The enhanced antioxidant defense possibly withdraws limited resources (e.g., energy or micronutrients) from other physiological functions, such as immune defense. Such a trade‐off might not occur outside the migration seasons or in resident individuals. Here, we investigate whether there is a negative relationship between innate immune function and antioxidant defense by sampling both migrating and resident blackbirds (Turdus merula) at the same location during the same period of the annual cycle. We show that in migrating blackbirds microbial killing capacity (BKA), an integrative measure of baseline innate immune function was negatively correlated with total nonenzymatic antioxidant capacity. In contrast, in resident conspecifics, sampled at the same time and location, these two physiological measures were not correlated. This suggests that migrating birds trade off innate immune function and antioxidant defense. Furthermore, and likely a consequence of this trade‐off, in migrant blackbirds BKA was positively correlated with oxidative damage to lipids. In resident blackbirds BKA and degree of lipid oxidation were uncorrelated. The mechanism and currencies of the supposed trade‐off are currently unknown, but energetic investments or micronutrients are likely candidates. Future experimental studies could provide more conclusive evidence for this trade‐off; yet, our results open up a new level of thinking about the physiological costs of migration.
Environmental filtering and dispersal as drivers of metacommunity composition: complex spider webs as habitat patches
Authors: Fernandez‐Fournier Philippe , Avilés Leticia 
Published: February 2018

AbstractMetacommunity theory has advanced the understanding of the patterns and processes shaping community structure at multiple scales. Various models have been put forward to explain the relative effects of environmental filtering, dispersal, and species traits on community composition. Here, we focus on complex, three‐dimensional webs of two social and two solitary spider species as habitat patches for associated communities of arthropods in a tropical rainforest in Ecuador. We used variance partitioning, constrained ordination, coherence analyses, and a colonization experiment to assess the role of environmental filtering and dispersal in this system. We found that the composition of communities associated with the four host species was mostly differentiated along two ordination axes, with the first axis roughly corresponding to level of sociality (solitary vs. social) and the other to web size. Associate abundance increased, but their density per unit volume decreased with host web size for all host species. Webs of social spider species had more variable communities and proportionally more aggressive (i.e., predatory) associates. After rarefaction to control for larger samples in larger webs, only one of the species showed a significant increase of species richness as a function of web size. The relatively quick colonization of experimentally established webs suggests high dispersal of more generalist species, but their lower proportion in older webs provides some evidence of a colonization–competition trade‐off at longer temporal scales. The distinctness of the communities associated with the four host species, and the eventual change in proportion of associates in newly founded vs. old webs, despite high dispersal, is consistent with environmental filtering and species traits playing a major role in determining patterns of species distribution in this system.
Light‐emitting Diode‐assisted Determination of 2‐(1,1‐Dimethylethyl)‐1,4‐Benzenediol in Cosmetic Samples Exploiting TiO2 Sensitized with Lithium 7,7′,8,8′‐Tetracyanoquinodimethanide
Authors: Oliveira Monteiro Thatyara , Costa dos Santos Clenilton , Santos Damos Flávio , de Cássia Silva Luz Rita 
Published: February 2018

AbstractThis paper reports a novel analytical device for the determination of 2‐(1,1‐dimethylethyl)‐1,4‐benzenediol antioxidant (TBHQ) in cosmetic samples exploiting a photoelectrochemical sensor based on titanium dioxide nanoparticles sensitized with lithium 7,7′,8,8′‐tetracyanoquinodimethanide on indium tin oxide electrode. The proposed photoelectrochemical sensor possesses the capacity of harvesting light energy from a commercial light‐emitting diode (LED) lamp for the determination of TBHQ molecules. The photoelectrochemical sensor presented photocurrent response to antioxidant about 2‐fold higher than pure titanium dioxide. The sensor shows high photocurrent response to TBHQ antioxidant in comparison to photocurrent response to 2,3‐t‐butyl‐4‐hydroxyanisole and 2,6‐Di‐tert‐butyl‐4‐methylphenol, indicating selectivity to TBHQ. Under optimized experimental conditions, the photoelectrochemical sensor presents two linear ranges of response for the analyte, the former from 0.6 to 200 μmol L−1, and the latter from 200 to 5000 μmol L−1. A low limit of detection of 0.17 μmol L−1 was obtained for the proposed photoelectrochemical sensor. The sensor was successfully employed to the analysis of cosmetic samples, with recovery values between 96 % and 98 %.
Electrochemical DNA Biosensor Based on Magnetite/Multiwalled Carbon Nanotubes/Chitosan Nanocomposite for Bacillus Cereus Detection of Potential Marker for Gold Prospecting
Authors: Zuo Limei , Qu Qing , Li Lei , Ran Xin , Gui Jingwei , Wang Qiang , Cui Xinhua , Jiang Changliang 
Published: February 2018

AbstractA label‐free DNA biosensor based on magnetite/multiwalled carbon nanotubes/chitosan (Fe3O4/MWCNTs‐COOH/CS) nanomaterial for detection of Bacillus cereus DNA sequences was fabricated. Negatively charged DNA was electrostatically adsorbed onto materials by protonation of positively charged chitosan under acidic conditions. The electrode surface and hybridization process were carried out by cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Under optimal conditions, the biosensor showed a good linear relationship between peak currents difference (ΔI) and logarithm of the target DNA concentration (Log C) ranging from 2.0×10−13 to 2.0×10−6 M with a detection limit of 2.0×10−15 M (signal/noise ratio of 3). The biosensor also revealed an excellent selectivity to three‐base, completely mismatched and completely matched DNA. This is a simple, fast and friendly method with a low detection limit for the detection of Bacillus cereus specific DNA compared with previously reported electrochemical DNA biosensor. Furthermore, the DNA biosensor may lead to the development of a technology for gold prospecting in the wild.
Effects of the liquid vapor oxygen transfer coefficient (kLα) on ethanol production from cassava residue and analysis of the fermentation kinetics
Authors: Li Xingjiang , Deng Yongdong , Wu Xuefeng , Yang Ying , Cao Lili , Yao Hongli , Mu Dongdong , Wang Hualin , Zheng Zhi , Jiang Shaotong 
Published: February 2018

AbstractCassava residue is the solid waste generated from the production of tapioca starch and has considerable reuse value. In this study, cassava residue was examined as a hydrolysate for ethanol production, and the effects of different liquid phase oxygen transfer coefficients (kLα) on the production of ethanol from cassava residue hydrolysates were studied. Based on analyses of dissolved oxygen and a set of optimal experimental schemes, dynamic models of cell growth and product synthesis were optimized, using MATLAB. When kLα was 85, fermentation was optimal; the ethanol titer reached 23.14 g L−1 at 72 h and cell growth reached 6.23 g L−1 at 96 h. Additionally, experiments were performed according to the dissolved oxygen curve obtained under these conditions. The resulting ethanol titer was 24.43 g L−1 (72 h) and the cell mass was 6.45 g L−1 (96 h).
Quantile estimators with orthogonal pinball loss function
Authors: Yu Lean , Yang Zebin , Tang Ling 
Published: February 2018

AbstractTo guarantee stable quantile estimations even for noisy data, a novel loss function and novel quantile estimators are developed, by introducing the effective concept of orthogonal loss considering the noise in both response and explanatory variables. In particular, the pinball loss used in classical quantile estimators is improved into novel orthogonal pinball loss (OPL) by replacing vertical loss by orthogonal loss. Accordingly, linear quantile regression (QR) and support vector machine quantile regression (SVMQR) can be respectively extended into novel OPL‐based QR and OPL‐based SVMQR models. The empirical study on 10 publicly available datasets statistically verifies the superiority of the two OPL‐based models over their respective original forms in terms of prediction accuracy and quantile property, especially for extreme quantiles. Furthermore, the novel OPL‐based SVMQR model with both OPL and artificial intelligence (AI) outperforms all benchmark models, which can be used as a promising quantile estimator, especially for noisy data.
Pt‐Sn‐Eu/C Catalysts: Application of Rare Earth Metals as Anodes in Direct Ethanol Fuel Cells
Authors: Corradini P. G. , Santos N. A. , Perez J. 
Published: February 2018

AbstractPt‐Sn‐Eu catalysts were synthesized by modified polyol method, evaluated for the ethanol oxidation reaction (EOR), and compared to commercial Pt/C and Pt‐Sn/C catalysts. The catalysts were electrochemically characterized in both three‐electrode and fuel cell setups. X‐ray diffraction measurements indicated some degree of Pt‐Sn alloying in the Pt‐Sn‐Eu/C catalysts, and mean crystallite sizes between 2.3–3.3 nm, while X‐ray photoelectron spectroscopy measurements showed the presence of Pt and Sn in both metallic and oxide form, and rare earth metals in the form of mixed oxides. Adding tin and europium promoted filling of the Pt 5d band, as confirmed by X‐ray absorption. The electrochemical characterization showed a higher oxidation current density and lower oxidation onset potential for the ternary Pt‐Sn‐Eu materials compared with the commercial catalysts, in both the three‐cell and fuel cell tests. High performance liquid chromatography measurements indicating that the main products of ethanol oxidation were acetaldehyde and acetic acid; a low concentration of CO2 was also detected. The improved ethanol oxidation efficiency for the Pt‐Sn‐Eu/C catalysts can be explained by the Sn/Eu‐Pt electronic effect, because it weakens the adsorption of intermediate products by Pt, and favors the bifunctional EOR mechanism, as europium oxide renders oxygenated species available at lower potentials.