bluuebunny/crossref_metadata_2025_split huggingface dataset:
Delocalization in Substituted Benzene Dications: A Magnetic Point of View
Authors: Orozco‐Ic Mesías , Barroso Jorge , Islas Rafael , Merino Gabriel 
Published: June 2020

AbstractIn this work, the induced magnetic field is analyzed for a series of substituted benzenes dications with formula C6R62+ (R=I, At, SeH, SeCH3, TeH, TeCH3), presumably exhibiting concentric aromaticity. Previous studies concluded that in the carbon skeleton, just π‐electrons are delocalized. However, our results support that both the σ‐ and π‐electrons are delocalized in the carbon skeleton, combined with a σ‐delocalization in the external ring. The role of the relativistic effects in these dications is discussed in detail.
Comparison of the effect of reactive and nonreactive treatments on the dispersion characteristics of a calcium carbonate (calcite) filler in a polypropylene matrix composite
Authors: Ersoy Orkun , Köse Harun 
Published: June 2020

AbstractThe excellent properties of the composites distinctly depend on the filler particles dispersion, which has close relationship with the surface treatment of filler particles. To improve the compatibility between the filler particles and the matrix, the surface of filler particles is generally treated with coating agents, which can be classified as “dispersants” and “coupling agents.” Coating calcite (CaCO3) with dispersants is called a nonreactive treatment. The surface modification of CaCO3 with coupling agents is called reactive treatment. In this study, physical, chemical, morphological, rheological, and mechanical analyses were conducted to determine the effect of reactive and nonreactive surface treatment agents on the dispersion of CaCO3 in polypropylene/CaCO3 composites. Both agents successfully made the surface of CaCO3 hydrophobic. The results of this study revealed that, although stearic acid (SA) establishes stronger bonds with the calcite surface, isopropyl tristearyl titanate, unlike SA, improves the properties of the final product composite, which forms a bond at the polymer/filler interface.
Enhancing the mechanical properties of 3D printed polylactic acid using nanocellulose
Authors: Ambone Tushar , Torris Arun , Shanmuganathan Kadhiravan 
Published: June 2020

AbstractWe report here a systematic investigation of the mechanical properties of polylactic acid (PLA) processed by fused filament fabrication (FFF) 3D printing vs PLA processed by compression molding. Our results show that the tensile strength and modulus of FFF‐PLA is 49% and 41% lower, respectively, than compression molded samples of PLA. We also demonstrate here an approach to augment the mechanical properties of 3D printed PLA using nanocellulose. Incorporation of a small quantity (1 wt%) of cellulose nanofibers (CNF) was found to enhance the tensile strength and modulus of 3D printed PLA by 84% and 63%, respectively. X‐ray microtomography was used to probe the morphology of 3D printed PLA and PLA/CNF composites. 3D printed PLA/CNF composites had significantly lesser voids as compared to neat 3D printed PLA. Differential scanning calorimetry study revealed that CNF can accelerate the nucleation and crystallization of 3D printed PLA leading to enhanced crystallinity. The thermal stability of 3D printed PLA/CNF composites was not compromised by the addition of CNF. The enhanced mechanical properties of 3D printed PLA/CNF composites can be ascribed to higher crystallinity and lesser defects.
Super‐crosslinked ionic liquid‐intercalated montmorillonite/epoxy nanocomposites: Cure kinetics, viscoelastic behavior and thermal degradation mechanism
Authors: Seidi Farzad , Jouyandeh Maryam , Akbari Vahideh , Paran Seyed Mohamad Reza , Livi Sebastian , Ducos Franck , Vahabi Henri , Ganjali Mohammad Reza , Saeb Mohammad Reza 
Published: June 2020

AbstractSuper‐crosslinked epoxy nanocomposites containing N‐octadecyl‐N′‐octadecyl imidazolium iodide (IM)‐functionalized montmorillonite (MMT‐IM) nanoplatelets were developed and examined for cure kinetics, viscoelastic behavior and thermal degradation kinetics. The structure and morphology of MMT‐IM were characterized by FTIR, XRD, TEM, and TGA. Synthesized MMT‐IM revealed synergistic effects on the network formation, the glass transition temperature (Tg) and thermal stability of epoxy. Cure and viscoelastic behaviors of epoxy nanocomposites containing 0.1 wt% MMT and MMT‐IM were compared based on DSC and DMA, respectively. Activation energy profile as a function of the extent of cure was obtained. DMA results indicated a strong interface between imidazole groups of MMT‐IM and epoxy, which caused a significant improvement in storage modulus and the Tg of epoxy. Network degradation kinetics of epoxy containing 0.5, 2.0, and 5.0 wt% MMT and MMT‐IM were compared by using Friedman, Kissinger‐Akahira‐Sunose (KAS), Flynn‐Wall‐Ozawa (FWO) and the modified Coats‐Redfern methods. Although addition of MMT to epoxy was detrimental to the Tg value, as featured by a fall from 94.1°C to 89.7°C detected by DMA method, and from 103.3°C to 97.9°C by DSC method, respectively. By contrast, meaningful increase in such values were observed in the same order from 94.1°C to 94.7°C and from 103.3°C to 104.7°C for super‐crosslinked epoxy/MMT‐IM systems.
Enzymatically forming cell compatible supramolecular assemblies of tryptophan‐rich short peptides
Authors: Yang Dongsik , Kim Beom Jin , He Hongjian , Xu Bing 
Published: June 2020

AbstractHere, we report a new type of tryptophan‐rich short peptides, which act as hydrogelators, form supramolecular assemblies via enzymatic dephosphorylation, and exhibit cell compatibility. The facile synthesis of the peptides starts with the production of phosphotyrosine and then uses solid‐phase peptide synthesis to build the phosphopeptides that contain multiple tryptophan residues. Besides exhibiting excellent solubility, these phosphopeptides, unlike the previously reported cytotoxic phenylalanine‐rich phosphopeptides, are largely compatible toward mammalian cells. Our preliminary mechanistic study suggests that the tryptophan‐rich peptides, instead of forming pericellular assemblies, largely accumulate in lysosomes. Such lysosomal localization may account for their cell compatibility. Moreover, these tryptophan‐rich peptides are able to transiently reduce the cytotoxicity of phenylalanine‐rich peptide assemblies. This rather unexpected result implies that tryptophan may act as a useful aromatic building block for developing cell compatible supramolecular assemblies for soft materials and find applications for protecting cells from cytotoxic peptide aggregates.
Compatibility, crystallinity and mechanical properties of poly(lactic acid)‐poly(ether‐block‐amide) based copper nanocomposites
Authors: Bautista‐Del‐Ángel Jesús E , Morales‐Cepeda Ana B , Wood‐Adams Paula M 
Published: June 2020

AbstractBinary and ternary composites of poly(lactic acid) (PLA), poly(ether‐block‐amide) (PEBAX) and copper nanoparticles were prepared by melt blending in an internal mixer. Compatibility and molecular interactions between the three components of the nanocomposites were evaluated using scanning electron microscopy and Fourier transform infrared spectroscopy. It was found that the carbonyl groups of the PLA and copper nanoparticles interact. Also, PLA and PEBAX are compatible and develop molecular interactions between the C=O of PLA and the C=O and NH of PEBAX, forming dipole–dipole bonds and hydrogen bonds. The compatibility and molecular interaction between PLA and PEBAX are reduced by copper nanoparticles. The reduction of compatibility between PLA and PEBAX produced a lower storage modulus and lower strain at break in the ternary systems than in the blend PLA‐PEBAX. Copper nanoparticles enhanced the crystallinity of PLA. PLA responded more strongly to the nucleating effect of copper when PEBAX was added indicating a synergistic effect. The strain at break of PLA was enhanced by the addition of PEBAX but was severely reduced by the presence of nanoparticles. © 2020 Society of Chemical Industry
Discriminating changes in protein structure using tyrosine conjugation
Authors: Moinpour Mahta , Barker Natalie K. , Guzman Lindsay E. , Jewett John C. , Langlais Paul R. , Schwartz Jacob C. 
Published: June 2020

AbstractChemical modification of proteins has been crucial in engineering protein‐based therapies, targeted biopharmaceutics, molecular probes, and biomaterials. Here, we explore the use of a conjugation‐based approach to sense alternative conformational states in proteins. Tyrosine has both hydrophobic and hydrophilic qualities, thus allowing it to be positioned at protein surfaces, or binding interfaces, or to be buried within a protein. Tyrosine can be conjugated with 4‐phenyl‐3H‐1,2,4‐triazole‐3,5(4H)‐dione (PTAD). We hypothesized that individual protein conformations could be distinguished by labeling tyrosine residues in the protein with PTAD. We conjugated tyrosine residues in a well‐folded protein, bovine serum albumin (BSA), and quantified labeled tyrosine with liquid chromatography with tandem mass spectrometry. We applied this approach to alternative conformations of BSA produced in the presence of urea. The amount of PTAD labeling was found to relate to the depth of each tyrosine relative to the protein surface. This study demonstrates a new use of tyrosine conjugation using PTAD as an analytic tool able to distinguish the conformational states of a protein.
Transcriptome analysis of putative detoxification genes in the Asian citrus psyllid, Diaphorina citri
Authors: Wu Zhongzhen , Pu Xinhua , Shu Benshui , Bin Shuying , Lin Jintian 
Published: June 2020

AbstractBACKGROUNDThe Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a notorious pest that transmits the causal agent of huanglongbing (also called citrus greening disease). Resistance to insecticide in this destructive pest poses a serious threat to the citrus industry. To date, no systemic studies on genes coding for detoxification enzymes has been carried out on D. citri.RESULTSMultiple transcriptomes were generated through deep sequencing of RNA libraries. Candidate genes potentially involved in detoxification including cytochrome P450 monooxygenases (CYPs), glutathione S‐transferases (GSTs), and esterases (ESTs) were systematically identified by searching the transcriptomes and a draft genome assembly. A total of 49, 14 and 20 genes were found encoding CYPs, GSTs, and ESTs, respectively, in D. citri. The total numbers of candidate detoxification genes were much smaller than the counterparts reported in other insect species, which may reflect the strict oligophagy of this insect species. Developmental stage‐ and tissue‐specific expression patterns of the identified genes as well as their responses to insecticide treatments identified a small set of genes that could participate in detoxifying plant secondary metabolites and insecticides.CONCLUSIONOur studies represent the most comprehensive investigation to date on identification, characterization and expression profiling of detoxification genes in D. citri. The information revealed in this study shall be useful in designing strategies to manage this important insect pest. © 2020 Society of Chemical Industry
Poly(vinylidene chloride)/Poly(chlorotrifluoroethylene‐co‐acrylates) Composite Latex Coating Cured at Room Temperature Showing an Excellent Corrosion Resistance
Authors: Wang Yanxu , Li Chao , Zhang Xiaopeng , Lin Qianqian , Jiang Yuan , Yuan Jinfeng , Pan Mingwang 
Published: June 2020

AbstractWe report the fabrication of a corrosion‐resistant and room‐temperature curing composite latex coating with simple and environmentally friendly characteristics. Poly(vinylidene chloride) (PVDC) seed latex was first synthesized by emulsion polymerization of vinylidene chloride (VDC) monomers, subsequently the core‐shell structure of PVDC/poly(chlorotrifluoroethylene‐co‐methyl methacrylate‐co‐butyl acrylate) (PVDC/PCMB) particles were prepared via seeded emulsion copolymerization of PVDC seed particles with chlorotrifluoroethylene (CTFE), methyl methacrylate (MMA), and butyl acrylate (BA) comonomers. Furthermore, the PVDC/PCMB composite waterborne coating was smoothly fabricated. Besides, the film‐forming and anticorrosive performances could be improved by adjusting the feed ratio of acrylate comonomers in the shell layer and the core‐shell ratio, which was attributed to the synergistic effect of the low‐temperature curing PCMB nanodomains and the anticorrosive PVDC nanodomains. Moreover, the PVDC/PCMB coating still showed the outstanding corrosion resistance even after immersion in 3.5 wt% NaCl solution for 400 h.
Silver‐Iodide‐Catalyzed One‐Pot Three‐Component Synthesis of 3‐Amino Furans in Water
Authors: Kumar Rapeti Siva , Chaitanya Kasina Krishna , Gundepaka Prasad , Birudaraju Saritha , Sailaja B. B.  
Published: June 2020

AbstractThe readily available and inexpensive silver iodide catalyzed one‐pot three‐component reaction of 2‐ketoaldehdyes, secondary amines and terminal alkynes to access 3‐amino furans in environmentally benign water proceeds via tandem Mannich‐Grignard addition followed by intramolecular cyclization was described for the first time.
Multipoint contact without forbearance? How coverage synergies shape equity analysts' forecasting performance
Authors: Uribe Jose N. 
Published: June 2020

AbstractResearch Summary:Scholars regularly use multipoint contact (MPC) to explain how encountering rivals in different domains shapes performance. While most explanations rely on mutual forbearance theory, I propose that competitive deterrence does not adequately explain how MPC shapes performance in knowledge intensive work and argue instead that cross‐domain synergies may play a central role. I examine how security analysts' MPC with publicly traded firms captures synergies in their coverage portfolio, which improves forecasting accuracy and information leadership. The advantages of greater MPC for a focal analyst are counterbalanced by rivals' observational learning, which reduces the focal analyst's forecasting differentiation. A natural experiment helps corroborate my argument: rival analysts' forecasting accuracy dropped for firms in which high MPC analysts perished in the terrorist attack on September 11, 2001.Managerial Summary:Competition in the knowledge economy often unfolds across multiple domains including product markets, geographic locations, and customer segments. In these settings, an actor's level of multipoint contact (MPC) in a domain captures the knowledge and other synergies available to the focal actor, which can improve performance in the domain. In the equity research setting, an analyst's MPC on a focal firm captures the likelihood that the analyst also covers that firm's suppliers, customers and important competitors. Using data on analysts' forecasting performance between 2001 and 2013, I find that greater levels of MPC on a focal firm predicts greater forecasting accuracy and information leadership but also lowers forecasting differentiation by attracting rivals who observe and benefit from the focal analyst's knowledge.
Decision weaving: Forming novel, complex strategy in entrepreneurial settings
Authors: Ott Timothy E. , Eisenhardt Kathleen M. 
Published: June 2020

AbstractResearch SummaryStrategy formation is central to why some firms seize novel opportunities while others fail. We explore a core dilemma of strategy formation in entrepreneurial settings—whether to learn a novel strategy one domain at a time (modular) versus assemble a complex strategy of coherent activities across all domains at once (integrative). By studying six ventures, we develop a theoretical framework for how entrepreneurs effectively form novel, complex strategy: Decision weaving. They (a) employ sequential focus (not parallel), (b) pause at plateaus (not optima), and (c) deploy stepping stones (not leaps) in background domains. These behaviors enable both fast, effective learning and evolving yet holistic understanding of an emerging strategy. Overall, we contribute to the microfoundations of strategy by proposing a cognitively sophisticated, yet realistic strategist.Managerial SummaryStrategy formation is central to why firms seize novel opportunities while others fail. By comparing three venture‐pairs, we develop a fresh framework for strategy formation in nascent markets where strategy is both novel and complex: Decision weaving. Effective strategists: (a) use sequential focus (not parallel) to learn about successive focal strategic domains, (b) pause at learning plateaus to consolidate that knowledge about a focal domain, and (c) use stepping stones to make progress in background domains without losing focus. These behaviors enable both fast, effective learning, and evolving yet holistic understanding of an emerging strategy. More importantly, these behaviors set the stage for rapid and profitable scaling (i.e., growth).
Corporate social responsibility of U.S.‐listed firms headquartered in tax havens
Authors: Lee Dongyoung 
Published: June 2020

AbstractResearch SummaryUsing 138 firm‐year observations for 46 U.S.‐listed firms headquartered in tax havens from 2004 to 2013, this study employs a matched‐sample design and documents that the level of corporate social responsibility (CSR) engagement is relatively lower for firms with tax haven headquarters (HQ) than for those with U.S. HQ. This result is robust to the use of firm philanthropy as a measure of CSR engagement and holds true in an environment with high CSR expectations from U.S. communities. In an alternative setting of HQ relocations within the United States, we use a difference‐in‐differences methodology and find that when firms move their HQ to states with lower corporate income taxes, they decrease the level of CSR engagement. Overall findings are consistent with corporate culture theory.Managerial SummaryThis article examines CSR engagement of U.S.‐listed firms headquartered in tax havens. Using data from 2004 to 2013, we find that firms with tax haven HQ exhibit a relatively lower level of CSR engagement than otherwise similar firms headquartered in the United States. In the same vein, tax‐haven‐headquartered firms tend to give less to charity, even when they face high CSR expectations from U.S. communities. In an alternative setting of HQ relocations within the United States, we document that the level of corporate social engagement is more likely to drop for firms that move their HQ to lower‐tax regions. We interpret our findings as evidence of corporate culture affecting both the tax avoidance and CSR activities of firms headquartered in tax havens.
Enhanced Photocatalytic H2‐Production Activity of CdS Quantum Dots Using Sn2+ as Cocatalyst under Visible Light Irradiation
Authors: Xiang Xianglin , Zhu Bicheng , Cheng Bei , Yu Jiaguo , Lv Hongjin 
Published: June 2020

AbstractHerein, oil‐soluble CdS quantum dots (QDs) are first prepared through a solvent‐thermal process. Then, oil‐soluble CdS QDs are changed into water‐soluble QDs via ligand exchange using mercaptopropionic acid as capping agent at pH 13. The photocatalytic performance is investigated under the visible light irradiation using glycerol as sacrificial agent and Sn2+ as cocatalyst. No H2‐production activity is observed for oil‐soluble CdS QDs. Water‐soluble CdS QDs exhibit significantly enhanced hydrogen evolution rate. When the concentration of cocatalyst Sn2+ increases to 0.2 × 10−3 m, the rate of hydrogen evolution reaches 1.61 mmol g−1 h−1, which is 24 times higher than that of the pristine water‐soluble CdS QDs. The enhanced H2‐production efficiency is attributed to the adsorption of Sn2+ ions on the surface of CdS QDs that are further reduced to Sn atoms by photogenerated electrons. The in situ generated Sn atoms serve as photocatalytic cocatalyst for efficient hydrogen generation.
X‐Ray‐Induced Growth Dynamics of Luminescent Silver Clusters in Zeolites
Authors: Fenwick Oliver , Coutiño‐Gonzalez Eduardo , Richard Fanny , Bonacchi Sara , Baekelant Wouter , de Vos Dirk , Roeffaers Maarten B. J. , Hofkens Johan , Samorì Paolo 
Published: June 2020

AbstractHerein, AlKα X‐rays are used to drive the growth of luminescent silver clusters in zeolites. The growth of the silver species is tracked using Auger spectroscopy and fluorescence microscopy, by monitoring the evolution from their ions to luminescent clusters and then metallic, dark nanoparticles. It is shown that the growth rate in different zeolites is determined by the mobility of the silver ions in the framework and that the growth dynamics in calcined samples obeys the Hill–Langmuir equation for noncooperative binding. Comparison of the optical properties of X‐ray‐grown silver clusters with silver clusters formed by standard heat treatment indicates that the latter have a higher specificity toward the formation of luminescent clusters of a specific (small) nuclearity, whereas the former produce a wide distribution of cluster species as well as larger nanoparticles.
Effect of aggressive environment on durability of concrete containing fibrous rubber shreds and silica fume
Authors: Gupta Trilok , Siddique Salman , Sharma Ravi K. , Chaudhary Sandeep 
Published: June 2020

AbstractThe present study deals with the investigation of durability properties of reinforced concrete fabricated by incorporating fiber type rubber shreds as fine aggregate in concrete and silica fume as a supplementary cementitious material. Concrete designs were produced to replace natural fine aggregate and cement by rubber shreds, and silica fume, respectively. The concrete mixes were studied for compressive strength up to 365 days, abrasion resistance, and water absorption up to 28 days. The carbonation and acid resistance (H2SO4 and HCl) properties were studied up to 90 and 180 days, respectively. Corrosion samples were tested up to 18 months for both macrocell current and half‐cell potential. The incorporation of rubber shreds lowered the compressive strength of concrete and resistance to water absorption, carbonation, and corrosion. However, the resistance to abrasion and acid attack was enhanced on the utilization of rubber shreds in concrete. The presence of silica fume considerably enhanced the mechanical and durability properties of rubber shreds concrete and lowered the probability of corrosion.
Single and combined effects of carbamazepine and copper on nervous and antioxidant systems of zebrafish (Danio rerio)
Authors: Jia Dantong , Li Xiuwen , Du Sen , Xu Ning , Zhang Wenming , Yang Ruyi , Zhang Yunhai , He Yide , Zhang Yongjun 
Published: June 2020

AbstractVarious pollutants co‐exist in the aquatic environment such as carbamazepine (CBZ) and copper (Cu), which can cause complex effects on inhabiting organisms. The toxic impacts of the single substance have been studied extensively. However, the studies about their combined adverse impacts are not enough. In the present study, zebrafish were exposed to environmental relevant concentrations of CBZ (1, 10, and 100 μg/L), Cu (0.5, 5, and 10 μg/L) and the mixtures (1 μg/L CBZ + 0.5 μg/L Cu, 10 μg/L CBZ + 5 μg/L Cu, 100 μg/L CBZ + 10 μg/L Cu) for 45 days, the effects on nervous and antioxidant systems of zebrafish were investigated. The results demonstrated that, in comparison with single exposure group, the combined presence of CBZ and Cu exacerbated the effect of antioxidant system (the ability of inhibition of hydroxyl radicals (IHR), superoxide dismutase (SOD), catalase (CAT) and glutathione S‐transferase (GST)) but not nervous system (Acetylcholinesterase [AChE]). The qPCR results supported the changes of corresponding enzymes activities. Hepatic histopathological analysis verified the results of biomarkers. Our work illustrated that the toxicity of mixed pollutants is very complicated, which cannot simply be inferred from the toxicity of single pollutant, and calls for more co‐exposure experiments to better understanding of the co‐effects of pollutants on aquatic organisms.