bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fabrication of tragacanth and water soluble tragacanth nanoparticles through electrospraying
Authors: Javadi Zhinoos , Tavanai Hossein , Allafchian Alireza , Morshed Mohammad 
Published: May 2018

This work reports the fabrication of tragacanth and water soluble tragacanth (WST) through electrospraying technique. Tragacanth is a biocompatible and biodegradable carbohydrate with a wide range of applications. Suspensions of tragacanth in water and water‐ethanol (70:30) were electrosprayed successfully. Moreover, deesterified tragacanth (WST), which is highly water soluble, was also successfully electrosprayed. The results showed that electrospraying technique is capable of producing tragacanth nanoparticles with an average size in the range of 30 to 50 nm, depending on the electrospraying conditions. Water soluble tragacanth gave rise to even smaller nanoparticles. It was also found that lowering feed rate, increasing nozzle‐ collector distance, and increasing voltage decrease the average size of the electrosprayed tragacanth nanoparticles. The molecular weight of tragacanth and WST was measured to be 610 and 301 KDa, respectively. The electrosprayed tragacanth and WST nanoparticles showed moisture regain of 50% and 75%, respectively. These values are much higher than that of their normal powder form. Fourier transform infrared proved the absence of ester groups in the WST as a result of deesterification. X‐ray diffraction studies showed an amorphous microstructure for both tragacanth and WST before electrospraying. After electrospraying, the amorphous structure of the 2 showed some orientation.
The effect of MWCNT on dynamic mechanical properties and crystallinity of in situ polymerized polyamide 12 nanocomposite
Authors: Faridirad Farzaneh , Barmar Mohammad , Ahmadi Shervin 
Published: May 2018

This work aims at investigating the dynamic mechanical properties of in situ anionic ring opening polymerized polyamide 12 in the presence of multi‐walled carbon nanotubes (MWCNT). According to the dynamic mechanical thermal analysis results, the addition of only 0.1 wt.% of MWCNTs led to 30% enhancement in modulus at room temperature which exhibited improved mechanical behavior of the nanocomposites. Test results showed that by the presence of 1.2% wt MWCNTs, the modulus is almost doubled, and it did not show any tangible changes by the addition of more nanotubes. Also, the effect of different frequencies on the viscoelastic behavior was investigated in order to determine the thermal transitions occurred in the synthesized nanocomposites. After that, the crystallinity of the samples has been studied using differential scanning calorimetry and X‐ray diffraction data in order to investigate the effect of MWCNT content on the crystals' dimension.
A detailed DFT/TDDFT study on excited‐state intramolecular hydrogen bonding dynamics and proton‐transfer mechanism of 2‐phenanthro[9,10‐d]oxazol‐2‐yl‐phenol
Authors: Zhang Tianjie , Yang Guang , Jia Min , Song Xiaoyan , Zhang Qiaoli , Yang Dapeng 
Published: May 2018

AbstractIn this present work, using density functional theory and time‐dependent density functional theory methods, we theoretically study the excited‐state hydrogen bonding dynamics and the excited state intramolecular proton transfer mechanism of a new 2‐phenanthro[9,10‐d]oxazol‐2‐yl‐phenol (2PYP) system. Via exploring the reduced density gradient versus sign(λ2(r))ρ(r), we affirm that the intramolecular hydrogen bond O1‐H2⋯N3 is formed in the ground state. Based on photoexcitation, comparing bond lengths, bond angles, and infrared vibrational spectra involved in hydrogen bond, we confirm that the hydrogen bond O1‐H2⋯N3 of 2PYP should be strengthened in the S1 state. Analyses about frontier molecular orbitals prove that charge redistribution of 2PYP facilitates excited state intramolecular proton transfer process. Via constructing potential energy curves and searching transition state structure, we clarify the excited state intramolecular proton transfer mechanism of 2PYP in detail, which may make contributions for the applications of such kinds of system in future.
Significant Enhancement of Hydrogen Production in MoS2/Cu2ZnSnS4 Nanoparticles
Authors: Li Yulan , Zhou Zhihua , Lin Yuelai , Ji Haining , Li Handong , Wu Jiang , Ashalley Eric , Usman Muhammad , Bao Jiming , Niu Xiaobin , Wang Zhiming 
Published: May 2018

AbstractHydrogen produced from water splitting is a renewable and clean energy source. Great efforts have been paid in searching for inexpensive and highly efficient photocatalysts. Here, significant enhancement of hydrogen production has been achieved by introducing ≈1 mol% of MoS2 to Cu2ZnSnS4 nanoparticles. The MoS2/Cu2ZnSnS4 nanoparticles showed a hydrogen evolution rate of ≈0.47 mmol g−1 h−1 in the presence of sacrificial agents, which is 7.8 times that of Cu2ZnSnS4 nanoparticles (0.06 mmol g−1 h−1). In addition, the MoS2/Cu2ZnSnS4 nanoparticles exhibited high stability, and only ≈3% of catalytic activity was lost after a long time irradiation (72 h). Microstructure investigation on the MoS2/Cu2ZnSnS4 nanoparticles reveals that the intimate contact between the nanostructured MoS2 and Cu2ZnSnS4 nanoparticles provides an effective one‐way expressway for photogenerated electrons transferring from the conduction band of Cu2ZnSnS4 to MoS2, thus boosting the lifetime of charge carriers, as well as reducing the recombination rate of electrons and holes.
Self‐Assembly of Ag6 Clusters into Nanowires for Nonenzymatic Electrochemical Sensing of Glucose
Authors: Gao Xiaohui , Lin Hancheng , Li Ping , Chen Wei 
Published: May 2018

AbstractSelf‐assembly of metal nanoclusters into 3D ordered superstructures and the exploration of their electrochemical properties are highly significant for fundamental research and practical application. In this study, atomically precise Ag6(NALC)5 nanoclusters are successfully synthesized and their structure is determined carefully. It is interesting that the prepared Ag6(NALC)5 nanoclusters can be self‐assembled into ultrafine nanowires, long ribbons, and finally 3D porous network in the mixed solution of water and ethanol, which can be attributed to the solvent polarity, static electricity interaction between ligands, and the possible Van der Waals attractions. Such assembly phenomenon lays a foundation for the future fabrication of silver clusters‐based nanodevices. In addition, the synthesized silver nanoclusters can be used for electrochemical sensing of glucose with high detection sensitivity, selectivity, and low limit of detection. This work is expected to be helpful for the synthesis of atomically precise metal nanoclusters and their applications in fabrication of nanodevices for chemical sensors.
Impact of a cystic fibrosis transmembrane conductance regulator (CFTR) modulator on high‐dose ibuprofen therapy in pediatric cystic fibrosis patients
Authors: Bruch Brittany A. , Singh Sachinkumar B. , Ramsey Laura J. , Starner Timothy D. 
Published: May 2018

AbstractBackgroundThis study was undertaken to determine if a clinically relevant drug‐drug interaction occurred between ibuprofen and lumacaftor/ivacaftor.MethodsPeak ibuprofen plasma concentrations were measured prior to and after lumacaftor/ivacaftor initiation. A Wilcoxon signed rank sum test was used to compare the values.ResultsNine patients were included in the final analysis. Peak ibuprofen plasma concentrations decreased an average of 36.4 mcg/mL after initiation of lumacaftor/ivacaftor with a relative reduction of 41.7%. The average peak plasma concentration was 84.2 mcg/mL (SD = 10.9) prior to lumacaftor/ivacaftor initiation and 47.9 mcg/mL (SD = 16.4) following initiation (P = 0.0039). Peak concentrations occurred at an average of 100 min (SD = 30) and 107 min (SD = 40) prior to and following lumacaftor/ivacaftor initiation, respectively.ConclusionsWe suggest a clinically relevant drug‐drug interaction exists between ibuprofen and lumacaftor/ivacaftor. Lumacaftor may cause subtherapeutic ibuprofen plasma concentrations due to the induction of CYP enzymes and increased metabolism of ibuprofen. Based on this analysis, we have modified our use of ibuprofen in several patients after evaluation of this drug‐drug interaction.
Parallel chromatography and in situ scattering to interrogate competing protein aggregation pathways
Authors: Gomes Diana , Kalman Rebecca K. , Pagels Rebecca K. , Rodrigues Miguel A. , Roberts Christopher J. 
Published: May 2018

AbstractProtein aggregation can follow different pathways, and these can result in different net aggregation rates and kinetic profiles. α‐chymotypsinogen A (aCgn) was used as a model system to quantitatively and qualitatively assess an approach that combines ex situ size‐exclusion chromatography (SEC) with in situ laser scattering (LS) to monitor aggregation vs. time. Aggregation was monitored for a series of temperatures and initial dimer (ID) levels for starting conditions that were primarily (> 97%) monomer, and under initial‐rate conditions (limited to low monomer conversion—less than 20% monomer mass loss), as these conditions are of most to interest to many pharmaceutical and biotechnology applications. SEC results show that modest decreases of ID levels can greatly reduce monomer loss rates, but do not affect the effective activation energy for aggregation. The normalized aggregation rates determined from LS were typically ∼ 1 order of magnitude higher than the corresponding rates from SEC. Furthermore, LS signals vs. time became variable and highly nonlinear with decreasing ID level, temperature, and/or total protein concentration. Temperature‐cycling LS experiments showed this corresponded to conditions where dimer/oligomer “seeding” was suppressed, and high levels of reversible oligomers (“prenuclei”) were formed prior to “nucleation” and growth of stable aggregates. In those conditions, aggregation rates inferred from LS and SEC are greatly different, as the techniques monitor different stages of the aggregation process. Overall, the results illustrate an approach for interrogating non‐native protein aggregation pathways, and potential pitfalls if one relies on a single method to monitor aggregation—this holds more generally than the particular methods here.
Statin use, high cholesterol and prostate cancer progression; results from HCaP‐NC
Authors: Allott Emma H. , Farnan Laura , Steck Susan E. , Song Lixin , Arab Lenore , Su L. Joseph , Fontham Elizabeth T. H. , Mohler James L. , Bensen Jeannette T. 
Published: May 2018

BackgroundStatin use is associated with lower advanced prostate cancer risk and reduced prostate cancer‐specific mortality, but prior studies were conducted mainly in white men. We examined the effect of statin use on risk of prostate cancer progression in a population‐based, minority‐enriched cohort.MethodsWe used data from prostate cancer cases (45% African American) diagnosed between 2004 and 2007 who participated in the Health Care Access and Prostate Cancer Treatment in North Carolina cohort (HCaP‐NC). We abstracted statin use at diagnosis. Men reported if they had ever been diagnosed with high cholesterol. Multivariable Cox proportional hazards analysis was used to examine associations between statin use and risk of prostate cancer progression (biochemical recurrence or secondary treatment), overall and by race. In secondary analysis, we examined the association between high cholesterol and risk of progression, overall, and by statin use.ResultsOf 669 men, 244 (36%) were statin users at diagnosis. During 3.8 years median follow‐up, 138 men experienced prostate cancer progression. There was no association between statin use and risk of progression, either overall (HR 1.03; 95%CI 0.72‐1.46) or stratified by race. High cholesterol was inversely associated with risk of progression, particularly among statin users (HR 0.43; 95%CI 0.20‐0.94; p‐interaction = 0.22) and in men with higher perceived access to care (HR 0.57; 95%CI 0.36‐0.90; p‐interaction = 0.03). Study limitations included a relatively small sample size, short follow‐up, and lack of data regarding post diagnosis statin use.ConclusionsStatin use at diagnosis was not associated with prostate cancer progression in the population‐based, minority‐enriched HCaP‐NC. Greater healthcare engagement, including actively controlling serum cholesterol, may be linked to better prostate cancer‐specific outcomes.
Fiprole insecticide resistance of Laodelphax striatellus: electrophysiological and molecular docking characterization of A2′N RDL GABA receptors
Authors: Sheng Cheng‐Wang , Casida John E , Durkin Kathleen A , Chen Feng , Han Zhao‐Jun , Zhao Chun‐Qing 
Published: May 2018

AbstractBACKGROUNDPhenylpyrazole (fiprole) insecticides, including ethiprole, fipronil and flufiprole with excellent activity on rice planthoppers, are very important in Asia but resistance has developed after decades of use. The molecular mechanism of fipronil‐ but not ethiprole‐resistance has been previously studied in rice planthoppers. In our laboratory, a small brown planthopper Laodelphax striatellus strain with ethiprole‐resistance was cultured and the molecular mechanisms of ethiprole resistance and of cross‐resistance among fiprole insecticides were investigated.RESULTSEthiprole‐resistant L. striatellus has >5000‐fold resistance compared to the susceptible strain, and exhibits around 200‐fold cross‐resistance with fipronil and flufiprole. RDL genes were isolated from susceptible and ethiprole‐resistant L. striatellus and expressed in Xenopus oocytes. Electrophysiological studies showed fiprole insecticides inhibited γ‐aminobutyric acid (GABA)‐induced current with IC50 = 0.1–1.4 μM to LsRDL‐S homomers. In LsRDL‐R with A2′N mutation, only 1–13% inhibition was observed on treatment with 10 μM ethiprole, fipronil or flufiprole. Homology models indicate A2′N mutation allows crosslinking hydrogen bonding between Asn sidechains at the 2′ position around the channel pore, blocking insecticides from interacting near this position. In contrast, insecticides showed favorable binding near A2′ in wild‐type L. striatellus.CONCLUSIONCross‐resistance is increasing for fiprole insecticides in L. striatellus and management strategies are necessary to minimize resistance. © 2018 Society of Chemical Industry
Does the presence of water clusters induce the binding affinity of CK2 halogen ligands?: A quantum chemical perspective study
Authors: Deepa Palanisamy , Vijaya Pandiyan B. , Kolandaivel Ponmalai 
Published: May 2018

AbstractProtein–ligand interaction is the key factor in modeling of drugs and water molecules act as a bridge in linking protein and ligand, which was clearly depicted by Deepa (Cryst. Growth Des. 2017, 17, 1299). This work is intended toward the significance of water cluster in the midst of ligand binding. Further the idea was accounted to have in‐depth analysis of the individual water molecules that interact with each part of the ligand, since in reality only very few crystal water molecules bind with the CK2 ligands. Further, bulk solvent effects have been modeled using Tomasi's polarized continuum model at M06‐2X/def2‐QZVP levels of theory has increased the stability of the complexes. The strength of individual water molecules and their binding nature with ligand will be depicted in detail by interaction energy and two body interaction energy calculations at M06‐2X/def2‐QZVP level of theory. The impact of noncovalent interactions (Hydrogen, σ‐hole and Π‐hole bonding) in bridging between water cluster cavity and ligand were deeply analysed using structural properties (bond distance and bond angle), 2DNCI plot, AIM and NBO analyses. The HOMO, LUMO energy values are discussed in detail for both monomer (ligand) and complexes (ligand with water clusters). It is expected that this study paves a novel path for the scientific community in modeling drugs with the clear understanding of the impact of water molecules on ligand.
Mechanical properties and characteristic of surface treated bamboo fiber reinforced PP/PS blends
Authors: Tang Gang , Gu Bangping , Hu Xiong , Wei Gaofeng , Claramunt Christophe , Liu Chengliang 
Published: May 2018

Bamboo fiber (BF) as organic filler is characterized by mechanical properties analysis and morphology examination for polypropylene (PP) and polystyrene (PS) matrix blends. Effects of different filler content on tensile strength, flexural properties, and impact strength are proposed. It is observed from scanning electron microscopy (SEM) studies that addition of BF is beneficial in increasing mechanical strength via increasing the interface dispersed phase. The optimum tensile properties and impact properties of BF content were at 40 wt% for PP/PS/BF composite on melt mixing conditions. The results showed a significant improvement in mechanical properties of PP/PS/BF ternary blend composite. Comparing with untreated BF, content of carbon and nitrogen of treated BF decreased to 66.57 and 2.31%, oxygen content increased to 21.07%, and silicon content increased from 0 to 10.04%. The element ratio of O/C, N/C, and Si/C changed to 31.65, 3.47, and 15.08, respectively.
Influence of ionic interfacial layers on electronic properties of Alq3/Si(100) interface
Authors: Mazur P. , Sito J. , Grodzicki M. , Lament K. , Crofton M. , Ciszewski A. 
Published: May 2018

The electronic structures of Alq3/Si(100), Alq3/LiBr/Si(100), and Alq3/KCl/Si(100) systems are presented in this report. Their energy level diagrams were prepared and discussed. The formation of the LiBr and KCl interfacial layers between an Alq3 film and a Si(100) substrate results in a decrease of the energy barrier at the interface. The studies were carried out in situ in ultrahigh vacuum by ultraviolet photoelectron spectroscopy. Alq3 as well as LiBr and KCl layers were vapour evaporated onto n‐type Si(100) crystal. The electron affinity of clean Si(100) surface was 4.0 eV, and the position of the valence band maximum was 0.7 eV below EF. The energetic distance between the valence band maximum of Si(100) and the highest occupied molecular orbital level were 1.5, 2.6, and 2.2 eV, for the Alq3/Si(100), Alq3/LiBr/Si(100), and Alq3/KCl/Si(100) systems, respectively.
Functional Ag‐Exchanged Zeolites as Biocide Agents
Authors: Cerrillo José Luis , Palomares Antonio Eduardo , Rey Fernando , Valencia Susana , Pérez‐Gago María Bernardita , Villamón Diana , Palou Lluís 
Published: May 2018

AbstractMaterials based on silver are used for controlling different pathogenic microorganisms. However, the influence of the silver carrier in the biocidal activity of the material has been scarcely reported. The present research is focused on studying the influence of zeolite properties on the biocidal activity of silver‐exchanged zeolites, acting as reservoirs of silver species. The biocidal action of Ag‐Faujasite (Ag‐FAU) and Ag‐Linde Type A (Ag‐LTA) zeolites, containing different silver contents, is studied against different types of bacteria and fungi. Importantly, zeolite structure is found to be a significant parameter for controlling the antibacterial activity of Ag‐exchanged zeolites. The results show that Ag‐FAU presents a higher activity than Ag‐LTA, because the topology of FAU combined with its highest Si/Al ratio favors the formation and release of silver species with important biocidal activity. Some insights on the bactericidal mechanism of Ag‐zeolites are envisaged by means of high resolution transmission electron microscopy, showing the multi‐targeted biocidal action of Ag species released from zeolites. Besides, it is shown that Ag‐zeolites are more active against bacteria than fungi. Antifungal activity is highly dependent on the fungi species and the structure of the zeolite is not as determinant as it is for the antibacterial activity.
Towards a theory of ecosystems
Authors: Jacobides Michael G. , Cennamo Carmelo , Gawer Annabelle 
Published: May 2018

Research Summary:The recent surge of interest in “ecosystems” in strategy research and practice has mainly focused on what ecosystems are and how they operate. We complement this literature by considering when and why ecosystems emerge, and what makes them distinct from other governance forms. We argue that modularity enables ecosystem emergence as it allows a set of distinct yet interdependent organizations to coordinate without full hierarchical fiat. We show how ecosystems address multilateral dependences based on various types of complementarities—supermodular or unique, unidirectional or bidirectional—which determine the ecosystem's value‐add. We argue that at the core of ecosystems lie nongeneric complementarities, and the creation of sets of roles that face similar rules. We conclude with implications for mainstream strategy and suggestions for future research.Managerial Summary:We consider what makes ecosystems different from other business constellations, including markets, alliances, or hierarchically managed supply chains. Ecosystems, we posit, are interacting organizations, enabled by modularity, not hierarchically managed, bound together by the nonredeployability of their collective investment elsewhere. Ecosystems add value as they allow managers to coordinate their multilateral dependence through sets of roles that face similar rules, thus obviating the need to enter into customized contractual agreements with each partner. We explain how different types of complementarities (unique or supermodular, generic or specific, uni‐ or bi‐directional) shape ecosystems and offer a “theory of ecosystems” that can explain what they are, when they emerge, and why alignment occurs. Finally, we outline the critical factors affecting ecosystem emergence, evolution, and success—or failure.
Revisiting the gender gap in CEO compensation: Replication and extension of Hill, Upadhyay, and Beekun's (2015) work on CEO gender pay gap
Authors: Gupta Vishal K. , Mortal Sandra C. , Guo Xiaohu 
Published: May 2018

Research Summary: The increasing number of women chief executives motivates considerable interest in examining possible gender differences in CEO compensation. Recently, Hill, Upadhyay and Beekun reported that female CEOs receive greater compensation than male CEOs, which runs counter to common wisdom that the gender pay gap in the labor market favors men over women. With the goal of contributing to cumulative knowledge development in this area, we seek to reexamine Hill et al.'s finding about gender differences in CEO compensation by extending the analyses further in time, using a larger sample of firms and more rigorous empirical analyses. Our findings, which are robust to different statistical procedures and econometric specifications, do not reveal reliable evidence for differences in compensation paid to male and female CEOs.Managerial Summary: For years, a lively debate has centered on the issue of gender pay gap. The ubiquity of the pay gap between men and women has recently been questioned by Hill et al. who identify the chief executive officer (CEO) role as a workplace position where women receive greater compensation than men. Our investigation examines whether women CEOs are indeed compensated substantively more than male CEOs. We seek to replicate earlier work by Hill and colleagues, using an expanded dataset over a longer period of time and with more rigorous analytical tools. We do not find reliable evidence for a difference in compensation paid to male and female CEOs, suggesting that claims about gender gap in CEO compensation favoring women over men may be premature.