bluuebunny/crossref_metadata_2025_split huggingface dataset:
0D–2D and 1D–2D Semiconductor Hybrids Composed of All Inorganic Perovskite Nanocrystals and Single‐Layer Graphene with Improved Light Harvesting
Authors: Chen Jia‐Shiang , Doane Tennyson L. , Li Mingxing , Zang Huidong , Maye Mathew M. , Cotlet Mircea 
Published: December 2017

AbstractIn this study, inorganic cesium lead iodide (CsPbI3) perovskite nanoparticles (PNPs) and perovskite nanowires (PNWs) with single‐layer graphene (SLG) are combined to obtain 0D–2D PNP–SLG and 1D–2D PNW–SLG hybrids with improved light harvesting. Time‐resolved single‐nanostructure photoluminescence studies of PNPs, PNWs, and related hybrids reveal (i) quasi‐two‐state photoluminescence blinking in PNPs, (ii) highly polarized photoluminescence emitted by PNWs and (iii) efficient interfacial electron transfer between perovskite nanostructures and SLG in both PNP–SLG and PNW–SLG hybrids. Doping of poorly absorbing, highly conductive SLG with perovskite nanocrystals and nanowires provides a simple, yet efficient path to obtain hybrids with increased light‐harvesting properties for potential utilization in the next‐generation photodetectors and photovoltaic devices, including polarization sensitive photodetectors.
Gold Nanoparticles‐Based DNA Logic Gate for miRNA Inputs Analysis Coupling Strand Displacement Reaction and Hybridization Chain Reaction
Authors: Ma Xiaoyi , Gao Liqian , Tang Yuguo , Miao Peng 
Published: December 2017

AbstractThe molecular level DNA logic gates assisted by nanomaterials hold great promise for disease diagnosis applications. However, designing convenient and sensitive logic gates for molecular diagnostics still remains challenging. In this work, a DNA logic gate platform for miRNA inputs analysis based on the observation of localized surface plasmon resonance variation of gold nanoparticles (AuNPs) is fabricated. As a demonstration, two biomarkers to differentiate indolent and aggressive forms of prostate cancer, miR‐200c and miR‐605, are selected as examples of logical inputs. In addition, five DNA probes are designed according to strand displacement reaction and hybridization chain reaction which are required for DNA logical operation. Since target miRNA inputs are able to trigger DNA structural transformations, which are further used to precisely regulate salt‐induced AuNPs aggregation, miRNA inputs information can be converted to the information of AuNPs states as outputs. This developed system performs amplified detection of low‐abundant target miRNAs without the requirement of any enzymes. In addition, single base‐pair mismatched miRNAs can be effectively differentiated. High‐order logic gates can also be developed with further modifications. Therefore, the DNA AND logic gate is successfully constructed with flexible operations, which has potential in biochemical study and disease diagnosis.
Controlling Au–Pd Surface on Au Nanocubes for Selective Catalytic Alkyne Semihydrogenation
Authors: Li Yaping , Liu Qiaoxi , Jin Jianbo , Ye Wei , Hu Canyu , Hu Shanwei , Qi Zeming , Long Ran , Song Li , Zhu Junfa , Xiong Yujie 
Published: December 2017

AbstractThe heterogeneous nanocatalyst based on palladium (Pd) is one of the most preferable choices for catalytic hydrogenation reactions as the adsorption and dissociation of hydrogen molecules (H2) are almost spontaneous on Pd surface to form the adsorbed H atoms (Had). However, in terms of alkyne semihydrogenation, it remains a grand challenge to optimize both the activity and selectivity of reactions using bare Pd catalysts as the case is largely complicated by the excessive Had produced from rapid H2 dissociation and the strong Pd‐H binding. In this communication, a well‐designed model is developed for seeking a selective semihydrogenation catalyst based on surface lattice engineering. In the proposed model, the ultrathin atomic layer of AuPd shell is grown on the Au nanocubes. The Au nanocubes provide specific facets as substrates for hosting catalytic sites, which can also provide information for further lattice engineering design. While Pd atoms are the active centers for hydrogenation reactions in the nanostructures, alloying Pd atoms with Au in the shells can significantly alter the binding of Had to metals. As such, the activity and selectivity in catalytic alkyne semihydrogenation can be substantially maneuvered by tailoring the atomic arrangement of Pd and Au on surface. As a proof of concept, the Au@AuPd nanocatalyst with a surface Pd/Au ratio of 1:4 achieves a 98.9% semihydrogenation selectivity with a conversion of 98.2% in the 2‐methyl‐3‐butyn‐2‐ol (MBY) hydrogenation reaction.
Development of an attract‐and‐kill co‐formulation containing Saccharomyces cerevisiae and neem extract attractive towards wireworms
Authors: Humbert Pascal , Vemmer Marina , Mävers Frauke , Schumann Mario , Vidal Stefan , Patel Anant V 
Published: December 2017

AbstractBACKGROUNDWireworms (Coleoptera: Elateridae) are major insect pests of worldwide relevance. Owing to the progressive phasing‐out of chemical insecticides, there is great demand for innovative control options. This study reports on the development of an attract‐and‐kill co‐formulation based on Ca‐alginate beads, which release CO2 and contain neem extract as a bioinsecticidal compound. The objectives of this study were to discover: (1) whether neem extract can be immobilized efficiently, (2) whether CO2‐releasing Saccharomyces cerevisiae and neem extract are suitable for co‐encapsulation, and (3) whether co‐encapsulated neem extract affects the attractiveness of CO2‐releasing beads towards wireworms.RESULTSNeem extract was co‐encapsulated together with S. cerevisiae, starch and amyloglucosidase with a high encapsulation efficiency of 98.6% (based on measurement of azadirachtin A as the main active ingredient). Even at enhanced concentrations, neem extract allowed growth of S. cerevisiae, and beads containing neem extract exhibited CO2‐emission comparable with beads without neem extract. When applied to the soil, the beads established a CO2 gradient of >15 cm. The co‐formulation containing neem extract showed no repellent effects and was attractive for wireworms within the first 24 h after exposure.CONCLUSIONCo‐encapsulation of S. cerevisiae and neem extract is a promising approach for the development of attract‐and‐kill formulations for the control of wireworms. This study offers new options for the application of neem extracts in soil. © 2017 Society of Chemical Industry
Effect of processing method on migration of antioxidant from HDPE packaging into a fatty food simulant in terms of crystallinity
Authors: Maghsoud Z. , Rafiei M. , Famili M.H.N. 
Published: December 2017

Migration of additives from plastic packaging into food products is generally considered to be affected by polymer crystallinity. In the present work, migration of Irganox 1010 from high density polyethylene into a fatty food simulant (ethanol 95%) was studied for samples prepared with different percent crystallinities. For this purpose, 2 different processing techniques, injection and compression molding, were used, and the preparation conditions were changed to obtain high density polyethylene samples with crystallinities in the range of 50 to 70%. Migration analysis was carried out at 121°C for 2 hours, and then at 40°C for 238 hours using high performance liquid chromatography. In general, the injection molded specimens had lower crystallinity and higher overall migration than the compression molded ones. A similar trend for both injection and compression molded samples was observed indicating that the overall migration was a function of crystallinity degree. However, the specific migration rates of Irganox 1010 especially before 50 hours were found to be different for the 2 processing methods because of dissimilar morphologies. Theoretical modeling based on Fickian diffusion was applied to give more insights into the involved processes during specific migration. The interaction of the food simulant with the polymer was taken into account considering the food sorption into the polymer. By fitting the model on experimental data, it was possible to obtain the model parameters such as partition coefficients (K) and the swelling constant (B) as a function of sample crystallinity.
Contamination test of metal and non‐metal elements from copper gas pipe to food gases
Authors: Capecchiacci Francesco , Tassi Franco , Vaselli Orlando 
Published: December 2017

In the last decade, EC regulations have been issued to minimize any interaction between packaging materials intended to come in contact with foodstuffs and potential contaminants. In this paper, the concentrations of 26 metals and metalloids in a food gas (CO2), possibly related to the migration of elements from copper pipes, which are commonly used during gas storage and distribution, were determined by ICP‐AES and ICP‐MS. A simple, though efficient, procedure to chemically trap these elements has shown that the copper pipes do not release significant concentrations of metals and metalloids, most of them being below or clustering below or around the instrumental detection limit. According to this study, only Al, Cu, Fe, Ni, and Zn can be related to the copper line. However, when considering the consumption of 3 L of water, at which 12 g/L of CO2 is added, the computed concentrations of metals and metalloids are 3 to 6 orders of magnitude lower than the limit concentrations in mineral waters intended for human consumption (European Directive 98/83/EC). This implies that the amount of contaminants in CO2 introduced in the human body is negligible.
Control chart for monitoring the coefficient of variation with an exponentially weighted moving average procedure
Authors: Zhang Jiujun , Li Zhonghua , Wang Zhaojun 
Published: December 2017

AbstractThe coefficient of variation (CV) of a population is defined as the ratio of the population standard deviation to the population mean, which can be regarded as a measure of stability or uncertainty and can also indicate the relative dispersion of data to the population mean. This paper proposes a new exponentially weighted moving average chart for monitoring CV, which is constructed by truncating those negative normalized observations to 0 in the traditional exponentially weighted moving average CV statistics. The implementation and optimization procedures of the proposed chart are presented. The new chart is compared with some existing CV charts by means of average run length, and the comparison results show that the new chart outperforms other charts in most cases. Two examples illustrate the use of this chart on real data gathered from a metal sintering process and from a die casting hot chamber process.
Lanthanide metals in the boron cages: Computational prediction of M@Bn (M = Eu, Gd; n = 38, 40)
Authors: Xi Cong , Yang Le , Liu Chang , You Peng , Li Lanlan , Jin Peng 
Published: December 2017

AbstractEndohedral metalloborofullerenes (EMBFs) are novel boron analogues of the famous endohedral metallofullerenes (EMFs). Many EMBFs have been proposed by theoretical calculations thus far. However, in sharp contrast to EMFs, which trap most of the lanthanides with f electrons inside the cages, the corresponding lanthanide‐based EMBFs have never been reported. In this work, the encapsulation of Eu and Gd in the B38 and B40 fullerenes was studied by means of density functional theory calculations. Our results revealed that Gd@B38(9A), Eu@B40(8B2), and Gd@B40(7A″) all favor the endohedral configuration, and the electronic structures can be described as Gd3+@
, Eu2+@
, and Gd3+@
with jailed f electron spins. The large binding energies and sizable HOMO–LUMO gaps suggest that they may be achieved experimentally. They feature σ and π double aromaticity, and their excellent stabilities were confirmed by the Born–Oppenheimer molecular dynamics simulations. Finally, the infrared and UV/vis spectra were simulated to assist experimental characterization.
Discrimination of constructed air samples using multivariate analysis of full scan membrane introduction mass spectrometry (MIMS) data
Authors: Richards L.C. , Davey N.G. , Fyles T.M. , Gill C.G. , Krogh E.T. 
Published: December 2017

RationaleVolatile and semi‐volatile organic compounds (S/VOCs) are important atmospheric pollutants affecting both human and environmental health. They are directly measured as an unresolved mixture using membrane introduction mass spectrometry (MIMS). We apply chemometric techniques to discriminate, classify, and apportion air samples from a variety of sources.MethodsFull scan mass spectra of lab‐constructed air samples were obtained using a polydimethylsiloxane membrane interface and an electron ionization ion trap mass spectrometer. Normalized full scan spectra were analyzed using principal component analysis (PCA), cluster analysis, and k‐nearest neighbours (kNN) for sample discrimination and classification. Multivariate curve resolution (MCR) was used to extract pure component contributions. Similar techniques were applied to VOC mixtures sampled from different woodsmoke emissions and from the headspace above aqueous hydrocarbon solutions.ResultsPCA successfully discriminated 32 constructed VOC mixtures from nearly 300 air samples, with cluster analysis showing similar results. Further, kNN classification (k = 1) correctly classified all but one test set sample, and MCR successfully identified the pure compounds used to construct the VOC mixtures. Real‐world samples resulting from the combustion of different wood species and those associated with water contaminated with different commercial hydrocarbon products were similarly discriminated by PCA.ConclusionsChemometric techniques have been evaluated using full scan MIMS spectra with a series of VOC mixtures of known composition containing known compounds, and successfully applied to samples with known sources, but unknown molecular composition. These techniques have application to source identification and apportionment in real‐world environmental samples impacted by atmospheric pollutants.
Optimization and validation of enhanced biological reduction of 1,2,3‐trichloropropane in groundwater
Authors: Schmitt Melissa , Varadhan Srinivasa , Dworatzek Sandra , Webb Jennifer , Suchomel Eric 
Published: December 2017

AbstractLaboratory and field demonstration studies were conducted to assess the efficacy of enhanced biological reduction of 1,2,3‐trichloropropane (TCP) in groundwater. Laboratory studies evaluated the effects of pH and initial TCP concentrations on TCP reduction and the activity of a microbial inoculum containing Dehalogenimonas (Dhg). Laboratory results showed successful reduction at a pH of 5 to 9 with optimal reduction at 7 to 9 and at initial TCP concentrations ranging from 10 to over 10,000 micrograms per liter (μg/L). Based on findings from the laboratory study, the effects of TCP concentration, geochemical conditions, and amendment concentration on bioremediation efficacy were investigated during a field demonstration at a site with relatively low initial concentrations of TCP (< 2 μg/L). The field demonstration included injection of emulsified vegetable oil (EVO) and lactate as a carbon substrate for biostimulation, followed by bioaugmentation using the microbial inoculum containing Dhg. Post‐injection performance monitoring demonstrated reduction of TCP to below laboratory detection limits (< 0.005 μg/L) after an initial lag period of approximately six months following injections. TCP reduction was accompanied by generation of the degradation byproduct propene. A marginal increase in TCP concentrations, potentially due to an influx of upgradient aerobic groundwater containing TCP, was observed eight months after injections thereby demonstrating the sensitivity of this bioaugmentation application to changes in geochemical parameters. Despite this marginal increase, performance monitoring results indicate continued TCP biodegradation 15 months after implementation of the injection program. This demonstration suggests that enhanced biodegradation of TCP by combining biostimulation and bioaugmentation may be a promising solution to the challenges associated with remediation of TCP, even when present at low part per billion concentrations in groundwater.
Modeling of water quality downgradient of a mulch biowall
Authors: Alexander Matthew L. , Adeniran Adewale , Tovar Caitlin 
Published: December 2017

AbstractGroundwater treatment biowalls may be located close to a surface water body to prevent contaminant discharge from a groundwater plume into the surface water. Groundwater contaminants passing through the biowall are treated within the biowall or immediately downgradient of the biowall. Biowalls designed and constructed for the treatment of chlorinated solvents typically contain either a solid and/or liquid source of organic carbon to promote contaminant degradation by enhanced anaerobic reductive dechlorination. Common solid organic materials in biowalls include wood mulch or similar waste plant material, and common liquid organic materials are vegetable oil (possibly emulsified) or other long‐chain fatty acids. Such biowalls then develop anaerobic conditions in the constructed biowall volume, and potentially downgradient, as dissolved oxygen originally present in the aquifer is consumed. This groundwater condition can lead to the appearance of sulfide if groundwater influent to the biowall contains moderate to high sulfate concentrations. Other researchers have presented evidence for groundwater conditions downgradient of a biowall or a permeable reactive barrier (PRB) that are altered in relation to groundwater quality, besides the desired effect of contaminant degradation or removal by precipitation. The objective of this work was to investigate with modeling the changes in downgradient groundwater species chemistry as a result of a constructed biowall. This was accomplished with a chemical species model to predict levels of sulfate and sulfide present in groundwater in close downgradient proximity to the biowall. The results indicate that downgradient chemical changes could impact a surface water body to which groundwater discharges. The model described could be enhanced by incorporating additional design variables that should be considered in biowall feasibility assessments.
Do remediation experts have what it takes to explain empirical uncertainty?
Authors: Hughes Kate 
Published: December 2017

AbstractWords matter in risk communication, and experts’ choice of words is critical when remediation risks are being explained to nonexperts. In risk communication studies, communication gaps between experts and nonexperts are investigated but there is lack of primary research. An Australian project addresses this shortcoming through research into communication about the risks of contaminated land remediation, and this paper provides some of its findings. Seventeen experts completed a questionnaire about the meaning of some scientific terms, and analysis found that they have capacity to improve communication through their selection and use of language.When experts undertake risk communication, the language they use may increase or reduce communication gaps. When the topic is uncertainty about health risks, communication gaps about the extent of uncertainty may reduce the effectiveness of social engagement, leading to unintended consequences such as cost overruns. This situation makes for a good case study since remediation is about benefit as well as risk, and communication about benefit, while desirable, may not always be achievable. The study suggests how to improve risk communication by exploring the accuracy, clarity, and depth of expert language. It identifies attributes of language that can bridge gaps in knowledge and understanding and characterizes them as integration mechanisms. These are defined as knowledge forms and mental processes that support cooperation between different epistemic communities to achieve mutually agreed outcomes. Two integration mechanisms are suggested. Bridging content addresses communication gaps through the selection of content (what knowledge is selected). Bridging process addresses communication gaps through the use of language (how knowledge is explained). Bridging content and bridging process can be expressed through cognitive and experiential platforms, or a blending of both, so whether words are positioned in the science‐based or mental model of risk communication, a utility value can be found in their quality, whether reflected by accuracy or the power to communicate meaning.
Cover time and mixing time of random walks on dynamic graphs
Authors: Avin Chen , Koucký Michal , Lotker Zvi 
Published: December 2017

AbstractThe application of simple random walks on graphs is a powerful tool that is useful in many algorithmic settings such as network exploration, sampling, information spreading, and distributed computing. This is due to the reliance of a simple random walk on only local data, its negligible memory requirements, and its distributed nature. It is well known that for static graphs the cover time, that is, the expected time to visit every node of the graph, and the mixing time, that is, the time to sample a node according to the stationary distribution, are at most polynomial relative to the size of the graph. Motivated by real world networks, such as peer‐to‐peer and wireless networks, the conference version of this paper was the first to study random walks on arbitrary dynamic networks. We study the most general model in which an oblivious adversary is permitted to change the graph after every step of the random walk. In contrast to static graphs, and somewhat counter‐intuitively, we show that there are adversary strategies that force the expected cover time and the mixing time of the simple random walk on dynamic graphs to be exponentially long, even when at each time step the network is well connected and rapidly mixing. To resolve this, we propose a simple strategy, the lazy random walk, which guarantees, under minor conditions, polynomial cover time and polynomial mixing time regardless of the changes made by the adversary.
Big splash, no waves? Cognitive mechanisms driving incumbent firms’ responses to low‐price market entry strategies
Authors: Luoma Jukka , Falk Tomas , Totzek Dirk , Tikkanen Henrikki , Mrozek Alexander 
Published: December 2017

Research Summary: Low‐price market entries, aiming for rapid sales growth, tend to prompt strong competitive reactions. This research explores whether and how firms using low‐price entry strategies can mitigate retaliatory incumbent reactions. An experiment with 656 managers shows that entrants can attenuate the strength of incumbents’ responses by fostering perceptions of high aggressiveness or low commitment. Entrants may be able to accomplish this by adjusting their entry strategy to embed (subtle) cues of aggressiveness and (lack of) commitment. A replication experiment with university students reinforces our overall theoretical argument. However, the results also indicate that the interpretation of cues embedded in the entry strategy may be affected by the experience of incumbent firm managers. Overall, these results clarify the cognitive foundations of competitive responses to market entry.
Managerial Summary: What drives incumbents to respond strongly to market entries, and what can the entrant, if anything, do to mitigate those responses? This research offers empirical evidence and theoretical insights for managers faced with these questions by shedding light on the thinking processes preceding competitive responses. The study shows that while managers are motivated to respond strongly to market entries that appear to be highly consequential to their business, these responses may be mitigated if the entrant manages to foster perceptions of high aggressiveness or low commitment to the market. Managers form these perceptions in part on the basis of the entrant’s behavior, creating an opportunity for entrants to adjust their entry strategies in a manner that demotivates strong competitive responses.