bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mn(I) and Fe(II)/PN(H)P Catalysts for the Hydrogenation of Ketones: A Comparison by Experiment and Calculation
Authors: Passera Alessandro , Mezzetti Antonio 
Published: July 2019

AbstractThe P‐stereogenic PN(H)P tridentate ligand HN(CH2CH2)2P(Me)R (R=Cy, 1 a; R=tBu, 1 b) gives the Mn(I) complexes [Mn(CO)3(PN(H)P)]Br, which were tested in the asymmetric H2 hydrogenation of ketones. The amido species [Mn(CO)2(PNP)], hydrides [MnH(CO)2(PN(H)P)], and the alkoxide complex
were detected by NMR spectroscopy. The manganese(I) derivative [Mn(CO)3(1 a)]Br was compared to its iron(II) analogue [FeHBr(CO)(1 a)] by kinetic and DFT studies. The DFT study suggests that both Mn(I) and Fe(II) operate via a bifunctional mechanism for H+/H− transfer with structurally similar enantiodetermining transition states and hence comparable enantioselectivity. The Mn(I) catalyst is less active than its Fe(II) analogue (k(Fe)/k(Mn)=ca. 30), which we attribute to the higher stability of the Mn(I) resting species, the off‐cycle alkoxo complex [Mn(OCH(Me)Ph))(CO)2(1 a)] that follows from the larger π delocalization onto the additional CO ligand as compared to [FeH(OCH(Me)Ph))(CO)(1 a)].magnified image
It's Just Math—Unless It's Toxic!
Authors: Myers Kayla , Giblin Elisabeth , Zell‐Kanter Michele 
Published: July 2019

AbstractObjectiveThe objective was to determine emergency medicine residents’ ability to perform pharmaceutical calculations.MethodsA six‐question needs‐assessment survey of emergency medicine residents was conducted at a citywide conference in 2016. Residents performed simple pharmaceutical calculations and were queried regarding resources they typically use to aid in performing calculations.ResultsFifty‐three emergency medicine residents out of 110 attendees (48%) completed the survey (postgraduate year [PGY]‐1 n = 27, PGY‐2 n = 13, PGY‐3 n = 8, PGY‐4 or above n = 5). Nearly 80% (n = 42) of all residents responded correctly to at least four of six questions (PGY‐1 = 70%, PGY‐2 = 86%, PGY‐3 = 88%, and PGY‐4 and above = 100%). Sixty‐five percent of PGY‐1s, 50% of PGY‐2s, and 75% of PGY‐3s thought that it was very important to correctly perform basic calculations. Google and Up To Date were frequently used to assist with calculations. More than 70% of all residents utilize clinical pharmacy (PharmD) staff for calculating doses. PharmD services were available at all times in the majority of survey responses.ConclusionsEmergency medicine residents performed poorly when completing pharmaceutical calculations. This may contribute to increased patient morbidity and mortality. Internet resource use increased as the years of training increased. PharmD services were extensively utilized by all resident regardless of years of training.
Population climatic history predicts phenotypic responses in novel environments for Arabidopsis thaliana in North America
Authors: Samis Karen E. , Stinchcombe John R. , Murren Courtney J. 
Published: July 2019

PremiseDetermining how species perform in novel climatic environments is essential for understanding (1) responses to climate change and (2) evolutionary consequences of biological invasions. For the vast majority of species, the number of population characteristics that will predict performance and patterns of natural selection in novel locations in the wild remains limited.MethodsWe evaluated phenological, vegetative, architectural, and fitness‐related traits in experimental gardens in contrasting climates (Ontario, Canada, and South Carolina, USA) in the North American non‐native distribution of Arabidopsis thaliana. We assessed the effects of climatic distance, geographic distance, and genetic features of history on performance and patterns of natural selection in the novel garden settings.ResultsWe found that plants had greater survivorship, flowered earlier, were larger, and produced more fruit in the south, and that genotype‐by‐environment interactions were significant between gardens. However, our analyses revealed similar patterns of natural selection between gardens in distinct climate zones. After accounting for genetic ancestry, we also detected that population climatic distance best predicted performance within gardens.ConclusionsThese data suggest that colonization success in novel, non‐native environments is determined by a combination of climate and genetic history. When performance at novel sites was assessed with seed sources from geographically and genetically disparate, established non‐native populations, proximity to the garden alone was insufficient to predict performance. Our study highlights the need to evaluate seed sources from diverse origins to describe comprehensively phenotypic responses to novel environments, particularly for taxa in which many source populations may contribute to colonization.
Generation of a Quadphoton via Seventh‐Order Nonlinear Susceptibility
Authors: Feng Yuan , Li Kangkang , Ahmed Irfan , Li Yameng , Li Wei , Lan Guangchen , Zhang Yanpeng 
Published: July 2019

AbstractWith a wide range of potential applications, the generation of nonclassical multiphoton and number states has attracted renewed interest recently. Here, a correlated quadphoton with seventh‐order nonlinear susceptibility is reported in which all four photons are simultaneously created via an eight‐wave mixing (EWM) process in an atomic medium. The efficiency of the pure EWM process is low, which results from the small order of magnitude of the seventh‐order nonlinear susceptibility (the quadphoton correlation with four periods corresponding to 8 channels and 12 resonance positions). But the EWM process has a strong dressing effect. It not only increases the nonlinear susceptibility, but also produces 15 or 16 resonance positions in the dressing state picture. In addition, with the energy conservation of these positions, 12 coherent channels can be generated in this system. According to the interference between multichannels of the quadphoton, the quadphoton coincidence count appears as a damped Rabi oscillation, which has eight or ten oscillation periods. If only the nonlinear optical response is considered, the coincidence counts of the quadphoton behave as a damped Rabi oscillation with periods that can be controlled by the dressing field. These outcomes may contribute to a new promising method for quantum communication.
Fabrication and characterization of graphene oxide modified polycarboxylic by in situ polymerization
Authors: Gao Ruijun , Yao Yan , Wang Ling , Wu Hao 
Published: July 2019

ABSTRACTGraphene oxide (GO) was modified by in situ esterification reaction with isopentenol polyoxyethylene ether (IPEG) to obtain GO precursor (GO‐IPEG) with some polymerization activity. GO‐modified polycarboxylic (GO‐PCE) was prepared by GO‐IPEG and acrylic acid (AA) using the method of in situ polymerization. The molecular structure of GO‐IPEG and GO‐PCE was characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectra, and nuclear magnetic resonance (NMR). The dispersion properties and dispersion stability of GO‐IPEG and GO‐PCE in water solution were studied by ultraviolet–visible (UV–vis) absorption spectra, zeta potential, and atomic force microscope. The results of FTIR, Raman, 1H‐NMR, and 13C‐NMR indicate that IPEG was successfully grafted onto the surface of GO and then fabricated with AA by in situ free‐radical polymerization. The results of UV–vis and zeta potential show that GO nanosheets have a better dispersion in GO‐IPEG or GO‐PCE system when the reaction time of GO and IPEG is 1 h, and the dispersion stability can reach up to 1 month. The better dispersion and application property are confirmed by atomic force microscopy image and cement fluidity, water reducing rate, and compression strength. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48316.
An Improved Metal‐to‐Ligand Charge Transfer Mechanism for Photocatalytic Hydrogen Evolution
Authors: Wang Sicong , Shen Chao , Xu Yanqi , Zhong Yunhao , Wang Chengyin , Yang Shengyang , Wang Guoxiu 
Published: July 2019

AbstractIt is of great significance to fabricate a full‐spectrum‐active photocatalysts for more efficient utilization of solar energy. An improved metal‐to‐ligand charge transfer (MLCT) mechanism is proposed for a photocatalyst based on graphitic carbon nitride (g‐C3N4). UV/Vis spectroscopy indicates that the as‐prepared photocatalyst absorbs light at λ<1100 nm. The rather stable photocatalyst is found to be 26.1 times more active in photocatalytic hydrogen evolution (868.9 μmol h−1 g−1) than bulk g‐C3N4 (B‐CN) under visible light. The material exhibits high activity under near‐infrared (NIR) irradiation (49.1 μmol h−1 g−1). The mechanism of photocatalytic activity and stability are investigated by both experiment and theory. This proposed mechanism may have great potential for engineering renewable photocatalysts in the future.
Thermal and flicker phase noise analysis in rotary traveling‐wave oscillator
Authors: Abbasalizadeh Soolmaz , Javadi Mohsen , Miar‐Naimi Hossein 
Published: July 2019

SummaryThis paper analyzes the thermally induced phase noise and the up‐conversion of flicker noise into phase noise of rotary traveling‐wave oscillator (RTWO). Based on the analyses, this paper extracts the closed‐form formulas for the thermal and flicker phase noise of the RTWO. This paper compares the theoretical results with appropriate simulations to evaluate the accuracy of the derived closed‐form formulas. Comparisons confirm the accuracy of the extracted phase noise formulas. By using the presented straightforward approach along with accurate phase noise formulas, the designers can understand the RTWO's design tradeoffs. Also, they can design the RTWO for a specific phase noise without needing lengthy simulations.
Design and implementation of a new four‐switch modified quasi Z‐source inverter with improved space vector control method
Authors: Khosravi Farshad , Mirzaei Amin , Rezvanyvardom Mahdi 
Published: July 2019

SummaryThis paper proposes a novel cost‐effective feature as a three‐phase four‐switch inverter utilizing a modified quasi Z‐source (MQZs) network. This inverter exploits a pulse‐width modulation (PWM) control strategy based on developed space vectors to provide balanced three‐phase output voltages and currents. It also has many applications such as the three‐phase induction motor (IM) with adjustable speed drive (ASD) fed by a DC and/or rectified AC supply. Unlike some other similar four‐switch inverters or converters, which can only work in step down (buck) mode or step up (boost) mode, this inverter can operate in both modes that depend on switching signals and due to adjusting the zero shoot‐through (Zsh‐th) duty cycle. It also decreases the total harmonic distortions (THD) of output voltages and currents. The MQZs inverter reduces the switching losses and the cost of topology in comparison with the conventional six‐switch topologies. The utilized control strategy can work well without any extra filtering circuit in DC side to eliminate the effect of the DC‐bus voltage ripples on the inverter output currents and voltages. The experimental results are found closely analogous and confirm the aforementioned features of the proposed topology compared with other traditional topologies, although the inverter output filter is a conventional LC filter.
Global change stressors alter resources and shift plant interactions from facilitation to competition over time
Authors: Alba Christina , Fahey Catherine , Flory S. Luke 
Published: July 2019

AbstractGlobal change stressors such as drought and plant invasion can affect ecosystem structure and function via mediation of resource availability and plant competition outcomes. Yet, it remains uncertain how native plants respond to drought stress that co‐occurs with potentially novel resource conditions created by a nonnative invader. Further, there is likely to be temporal variation in competition outcomes between native and nonnative plant species depending on which resources are most limiting at a given time. Interacting stressors coupled with temporal variation make it difficult to predict how global change will impact native plant communities. To address this knowledge gap, we conducted a 5‐yr factorial field experiment to quantify how simulated drought, plant invasion (by cogongrass,Imperata cylindrica), and these stressors combined, affected resource availability (soil moisture and light) and competition dynamics between the invader and native longleaf pine (Pinus palustris), a foundation species in southeastU.S.forests. Drought and invasion mediated the survival and performance of pine seedlings in temporally dynamic and unexpected ways. Drought and invasion alone each significantly reduced pine seedling survival. However, when the stressors occurred together, the invader offset drought stress for pine seedlings by maintaining high levels of soil moisture, humidity, and shade compared to uninvaded vegetation. This facilitative effect was pronounced for 2 yr, yet shifted to strong competitive exclusion as the invasion progressed and the limiting resource switched from soil moisture to light. After 3 yr, pine tree survival was low except for pines growing with uninvaded vegetation under ambient precipitation conditions. After 5 yr, pines experiencing a single stressor were taller and had greater height to diameter ratios than pines under no stress or both stressors. This outcome revealed a filtering effect where poorly performing trees were culled under stressful conditions, especially when pines were growing with the invader. Together, these results demonstrate that although drought and invasion suppressed a foundation tree species, the invader temporarily moderated stressful drought conditions, and at least some trees were able to survive despite increasingly strong competition. Such unpredictable effects of interacting global change stressors on native plant species highlight the need for additional long‐term studies.
CD200R1 regulates eosinophilia during pulmonary fungal infection in mice
Authors: Salek‐Ardakani Samira , Bell Thomas , Jagger Christopher P , Snelgrove Robert J , Hussell Tracy 
Published: July 2019

AbstractCD200 receptor 1(CD200R1) signalling limits myeloid cell responses and reduces autoimmunity, alloimmunity and viral‐mediated immunopathology, but has never been examined in the context of eosinophilic inflammation. Susceptibility to lung fungal infection is associated with T‐helper 2 (Th2) cytokine dominated responses and strong eosinophilic pathology. Blockade of CD200R1 enhances type I cytokine responses in many infectious and non‐infectious settings and so may promote a more protective response to fungal infection. By contrast, we demonstrate that, rather than promoting type I cytokine responses, CD200R1 blockade enhanced eosinophilia in a mouse model of Cryptococcus neoformans infection, whereas CD200R1 agonism reduced lung eosinophilia – with neither strategy completely altering fungal burden. Thus, we reveal a surprising disconnect between pulmonary eosinophilia and cryptococcal burden and dissemination. This research has 2 important implications. Firstly, a lack of CD200R1 signalling enhances immune responses regardless of cytokine polarisation, and secondly reducing eosinophils does not allow protective immunity to develop in susceptible fungal system. Therefore, agonists of CD200R1 may be beneficial for eosinophilic pathologies.
Analysis of scaling of thickness of the buffer layer on analog/RF and circuit performance of InAs‐OI‐Si MOSFET using NQS model
Authors: Maity Subir Kumar , Pandit Soumya 
Published: July 2019

AbstractWith use of III‐V material in the channel region of a metal‐oxide‐semiconductor (MOS) transistor, interface buffer layers above and below the channel region are necessary to reduce several sources of scattering of the inversion charge carriers. This work presents a detailed analysis of effect of scaling down thickness of the top buffer layer of a buffered InAs‐OI‐Si metal‐oxide‐semiconductor field effect transistor (MOSFET) on electrostatic integrity, carrier mobility, analog/RF, linearity, and circuit performance using well‐calibrated 2D technology computer‐aided design simulation. We further develop non–quasi‐static small‐signal equivalent circuit model of the device. The model results have been compared with experimental results and good accuracy of our model is demonstrated. Both the model and numerical simulation results have been used in our study. In‐depth analysis of behaviour of several performance parameters at DC and radio frequency (RF) is presented with analytical explanations and numerical simulation results. A common source amplifier is designed and simulated in SPICE framework using the equivalent circuit model. From the study, we find that the quantum well that is formed in the buffer/channel/buffer layers needs to be formed as near to the oxide/semiconductor interface as possible for optimum performance.
Metabolite composition of sinking particles differs from surface suspended particles across a latitudinal transect in the South Atlantic
Authors: Johnson Winifred M. , Longnecker Krista , Kido Soule Melissa C. , Arnold William A. , Bhatia Maya P. , Hallam Steven J. , Van Mooy Benjamin A. S. , Kujawinski Elizabeth B. 
Published: July 2019

AbstractMarine sinking particles transport carbon from the surface and bury it in deep‐sea sediments, where it can be sequestered on geologic time scales. The combination of the surface ocean food web that produces these particles and the particle‐associated microbial community that degrades them creates a complex set of variables that control organic matter cycling. We use targeted metabolomics to characterize a suite of small biomolecules, or metabolites, in sinking particles and compare their metabolite composition to that of the suspended particles in the euphotic zone from which they are likely derived. These samples were collected in the South Atlantic subtropical gyre, as well as in the equatorial Atlantic region and the Amazon River plume. The composition of targeted metabolites in the sinking particles was relatively similar throughout the transect, despite the distinct oceanic regions in which they were generated. Metabolites possibly derived from the degradation of nucleic acids and lipids, such as xanthine and glycine betaine, were an increased mole fraction of the targeted metabolites in the sinking particles relative to surface suspended particles, while algal‐derived metabolites like the osmolyte dimethylsulfoniopropionate were a smaller fraction of the observed metabolites on the sinking particles. These compositional changes are shaped both by the removal of metabolites associated with detritus delivered from the surface ocean and by production of metabolites by the sinking particle‐associated microbial communities. Furthermore, they provide a basis for examining the types and quantities of metabolites that may be delivered to the deep sea by sinking particles.
(3 + 1)‐Dimensional time‐fractional modified Burgers equation for dust ion‐acoustic waves as well as its exact and numerical solutions
Authors: Tian Runhua , Fu Lei , Ren Yanwei , Yang Hongwei 
Published: July 2019

In this paper, the theoretical model of dust ion‐acoustic waves in collisionless, unmagnetized dust plasma is analyzed. According to the (3 + 1)‐dimensional nonlinear dynamic propagation equations with the electron distribution in the presence of trapping particles and the kinetic equation of charge of dust particle, based on multiscale analysis and perturbation method, a new (3 + 1)‐dimensional modified Burgers equation is constructed. Because of the space property of dust plasma, (3 + 1)‐dimensional modified Burgers equation is more suitable than low‐dimensional equation to describe the dust ion‐acoustic waves. Furthermore, applying the semi‐inverse method and the fractional variational principle, time‐fractional modified Burgers equation is given, which owns potential value for comprehending the propagation feature of dust ion‐acoustic waves in three‐dimensional space. Following, the conservation laws of the time‐fractional modified Burgers equation are discussed by using the Noether method. Finally, the shock wave solutions of the new model is obtained with the help of the G′/G‐expansion method; meanwhile, the radial basis function method is also used to get the numerical solutions of the (3 + 1)‐dimensional time‐fractional modified Burgers equation.
Optimisation of phytochemical characteristics and antioxidative properties of Foeniculum vulgare Mill. seeds and Ocimum basilicum L. leaves superfine powders using new parting process
Authors: Mousavi Mahta , Zaiter Ali , Becker Loïc , Modarressi Ali , Baudelaire Elie , Dicko Amadou 
Published: July 2019

AbstractIntroductionFennel (Foeniculum vulgare Mill.) and basil (Ocimum basilicum L.) are two aromatic medicinal plants. Recently, a new parting process which is named CDS “Comminution and to control Diffraction Sieving” is taken into consideration and its positive effect on the extraction of bioactive compounds from the plants, without any solvent, is reported.ObjectiveStudy the effect of CDS on phytochemical properties of superfine powders of fennel seeds and basil leaves.MethodsFennel seeds and basil leaves superfine powders were fractionated as follows: 100–180 μm, 180–315 μm, 315–500 μm, > 500 μm and unsieved superfine powders. Extraction of polyphenols was carried out using hydromethanolic maceration. The essential oils were extracted by maceration with dichloromethane. The antioxidant activities were evaluated by DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) assay. Using liquid chromatography ultraviolet electrospray ionisation mass spectrometry (LC‐UV‐ESI‐MS), concentrations of characterised phenolic compounds were measured. The essential oils compositions were characterised using gas chromatography mass spectrometry (GC–MS).ResultsIn fennel seeds, the 100–180 μm fraction had maximum antioxidant activity and LC‐UV‐ESI‐MS analyses proved that the best extraction of certain polyphenols was obtained in the 100–180 μm fraction. In basil leaves, the best antioxidant activity corresponded to the 315–500 μm fraction and LC‐UV‐ESI‐MS analyses showed that the polyphenols were concentrated in the < 315 μm fractions. For both plants, GC–MS presented that the essential oils were concentrated in the 315–500 μm fraction.ConclusionCDS as a new green parting process leads to improve the phytochemical properties of these two superfine plant powders in the specific granulometric classes.
F‐theory and Dark Energy
Authors: Heckman Jonathan J. , Lawrie Craig , Lin Ling , Zoccarato Gianluca 
Published: July 2019

AbstractMotivated by its potential use as a starting point for solving various cosmological constant problems, we study F‐theory compactified on the warped product where Y8 is a manifold, and the S3 factor is the target space of an Wess–Zumino–Witten (WZW) model at level N. Reduction to M‐theory exploits the abelian duality of this WZW model to an orbifold. In the large N limit, the untwisted sector is captured by 11D supergravity. The local dynamics of intersecting 7‐branes in the geometry is controlled by a Donaldson–Witten twisted gauge theory coupled to defects. At late times, the system is governed by a 1D quantum mechanics system with a ground state annihilated by two real supercharges, which in four dimensions would appear as “ supersymmetry” on a curved background. This leads to a cancellation of zero point energies in the 4D field theory but a split mass spectrum for superpartners of order specified by the IR and UV cutoffs of the model. This is suggestively close to the TeV scale in some scenarios. The classical 4D geometry has an intrinsic instability which can produce either a collapsing or expanding Universe, the latter providing a promising starting point for a number of cosmological scenarios. The resulting 1D quantum mechanics in the time direction also provides an appealing starting point for a more detailed study of quantum cosmology.