bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Enantioselective Povarov Reactions of Ferrocenecarbaldehyde‐Derived Imines – Brønsted Acid Catalysis at Parts‐Per‐Million Level Loading
Authors: Stevanović Dragana , Bertuzzi Giulio , Mazzanti Andrea , Fochi Mariafrancesca , Bernardi Luca 
Published: December 2017

AbstractDespite the broad interest in ferrocene containing compounds, ferrocenyl substrates have been employed in catalytic asymmetric settings only sporadically. Herein, catalytic asymmetric Povarov reactions with ferrocenecarbaldehyde‐derived N‐aryl imines are presented. This study demonstrates that the stereoelectronic properties of ferrocenyl imines do not preclude their engagement in enantioselective phosphoric acid catalysis: cycloadducts derived from benzyl N‐vinylcarbamate were obtained in good yields and nearly enantiopure form using 0.1 mol% of a standard Brønsted acid catalyst. Furthermore, it is shown that specific optimisation with some substrates allowed to lower the catalyst loading up to 10–20 parts‐per‐million, an unprecedented value for phosphoric acid catalysts. Such low loading protocol could be applied to a preparative scale reaction, and to imines derived from arylaldehydes.magnified image
Desktop NMR and Its Applications From Materials Science To Organic Chemistry
Authors: Blümich Bernhard , Singh Kawarpal 
Published: December 2017

AbstractNMR spectroscopy is an indispensable method of analysis in chemistry, which until recently suffered from high demands for space, high costs for acquisition and maintenance, and operational complexity. This has changed with the introduction of compact NMR spectrometers suitable for small‐molecule analysis on the chemical workbench. These spectrometers contain permanent magnets giving rise to proton NMR frequencies between 40 and 80 MHz. The enabling technology is to make small permanent magnets with homogeneous fields. Tabletop instruments with inhomogeneous fields have been in use for over 40 years for characterizing food and hydrogen‐containing materials by relaxation and diffusion measurements. Related NMR instruments measure these parameters in the stray field outside the magnet. They are used to inspect the borehole walls of oil wells and to test objects nondestructively. The state‐of‐the‐art of NMR spectroscopy, imaging and relaxometry with compact instruments is reviewed.
Kirmse–Doyle‐ and Stevens‐Type Rearrangements of Glutarate‐Derived Oxonium Ylides
Authors: Skrobo Benedikt , Schlörer Nils E. , Neudörfl Jörg‐M. , Deska Jan 
Published: December 2017

AbstractA novel chemoenzymatic synthetic cascade enables the preparation of densely decorated tetrahydrofuran building blocks. Here, the lipase‐catalyzed desymmetrization of 3‐alkoxyglutarates renders highly enantioenriched carboxylic acid intermediates, whose subsequent activation and oxonium ylide rearrangement by means of rhodium or copper complexes furnishes functionalized O‐heterocycles with excellent diastereoselectivity. The two‐step protocol offers a streamlined and flexible synthesis of tetrahydrofuranones bearing different benzylic, allylic or allenylic side chains with full control over multiple stereogenic centers.
Controllable Syntheses of MOF‐Derived Materials
Authors: Zou Kang‐Yu , Li Zuo‐Xi 
Published: December 2017

AbstractMetal–organic frameworks (MOFs), as an important kind of porous inorganic‐organic hybrid materials with inherent outstanding physicochemistry characteristics, can be widely applied as versatile precursors for the facile preparation of functional MOF‐derived materials. However, there are plenty of sophisticated factors during the synthetic process, which is far from reaching the goal of effectively controlling the nature of MOF‐derived materials (such as the composition, morphology and surface area). Therefore, it is urgently necessary to develop regular protocols and concepts for controllable syntheses of MOF‐derived materials. In this minireview, we mainly summarize and analyze complicated factors in the fabrication of MOF‐derived materials according to recently reported literatures, and this provides a new insight into the rational design and syntheses of MOF‐derived materials.
Customizing Photoredox Properties of PXX‐based Dyes through Energy Level Rigid Shifts of Frontier Molecular Orbitals
Authors: Sciutto Andrea , Fermi Andrea , Folli Andrea , Battisti Tommaso , Beames Joseph M. , Murphy Damien M. , Bonifazi Davide 
Published: December 2017

AbstractHere we describe the synthesis of electron‐rich PXX derivatives in which the energy levels of the excited states have been rigidly shifted through the insertion of imide groups. This has allowed the development of a new series of oxygen‐doped photoredox‐active chromophores with improved oxidizing and reducing properties. Capitalizing on the dehalogenation of organic halides as a model reaction, we could investigate the photooxidative and photoreductive potential of these molecules in model chemical transformations. Depending on the substrate, solvent and dye the reaction mechanism can follow different paths. This prompted us to consider the first chemoselective transformation protocol, in which two different C−Br bonds could be chemoselectively reacted through the sequential photoactivation of two different colorants.
Travel distance and stereotactic body radiotherapy for localized prostate cancer
Authors: Mahal Brandon A. , Chen Yu‐Wei , Sethi Roshan V. , Padilla Oscar A. , Yang David D. , Chavez Janice , Muralidhar Vinayak , Hu Jim C. , Feng Felix Y. , Hoffman Karen E. , Martin Neil E. , Spratt Daniel E. , Yu James B. , Orio Peter F. , Nguyen Paul L. 
Published: December 2017

BACKGROUNDDefinitive stereotactic body radiotherapy (SBRT) represents an emerging and debated treatment option for patients with prostate cancer, with potential economic savings and reports of short‐term efficacy since 2006. The current study sought to define national trends in definitive prostate SBRT use and determine whether patterns vary by travel distance for treatment.METHODSThe National Cancer Data Base identified 181,544 men with localized prostate cancer who were treated with definitive external beam radiotherapy from 2004 through 2012. Joinpoint regression analyzed definitive prostate SBRT trends over time, whereas multivariable logistic regression defined the odds for its receipt by travel distance for treatment.RESULTSDefinitive prostate SBRT use increased from 1.8% in 2004 to 5.9% in 2012 (P for trend <.0001), with a joinpoint for increased use noted in 2006 (P<.0001). Higher SBRT use was found to be associated with longer travel distance for treatment, younger age, white race, more affluent zip code of residence, academic treatment center, favorable disease characteristics, and fewer comorbidities (all P<.0001). Compared with travel distances <25 miles for treatment, travel distances of 25 to 50 miles and >50 miles were associated with increasing adjusted odds of receipt of definitive prostate SBRT (1.63 [95% confidence interval, 1.51‐1.76] and 2.35 [95% confidence interval, 2.14‐2.57], respectively; both P < .0001).CONCLUSIONSDefinitive prostate SBRT use increased more than 3‐fold since 2004, with a significant increase in use coinciding with early reports of short‐term efficacy. Long‐distance travel for treatment was associated with greater than twice the odds of receipt of definitive prostate SBRT compared with short‐distance travel, suggesting that treatment decisions with unknown long‐term clinical implications may be strongly driven by sociodemographic factors. Cancer 2018;124:1141‐9. © 2017 American Cancer Society.
The Role of Normative CSR‐Promoting Institutions in Stimulating CSR Disclosures in Developing Countries
Authors: Ali Waris , Frynas Jedrzej George 
Published: December 2017

AbstractThis paper provides evidence that CSR (corporate social responsibility) forums and networks such as the United Nations Global Compact Local Network (UNGC), non‐governmental organizations (NGOs) such as the World Wide Fund (WWF) for Nature, and CSR standards such as International Organization for Standardization (ISO) 14000 play a significant role in driving CSR disclosure, using data from publicly quoted companies in Pakistan. The role of CSR‐promoting institutions in enhancing capacity can provide a key explanation for the previously noted differences in disclosure patterns between developed and developing countries, on the one hand, and the improved disclosure in developing countries linked to the development of such institutions, on the other. Academically, this research demonstrates the vital importance of CSR‐promoting institutions, and the related normative isomorphism logics, for CSR disclosure in lower‐income countries, which have previously been assumed to largely lack such institutions. In practical terms, the significant relationship between CSR‐promoting institutions and CSR disclosure suggests that we need stronger policies to encourage the development of such institutions. Copyright © 2017 John Wiley & Sons, Ltd and ERP Environment
Magnetic Field‐Enhanced 4‐Electron Pathway for Well‐Aligned Co3O4/Electrospun Carbon Nanofibers in the Oxygen Reduction Reaction
Authors: Zeng Zheng , Zhang Tian , Liu Yiyang , Zhang Wendi , Yin Ziyu , Ji Zuowei , Wei Jianjun 
Published: December 2017

AbstractThe sluggish reaction kinetics of the oxygen reduction reaction (ORR) has been the limiting factor for fuel energy utilization, hence it is desirable to develop high‐performance electrocatalysts for a 4‐electron pathway ORR. A constant low‐current (50 μA) electrodeposition technique is used to realize the formation of a uniform Co3O4 film on well‐aligned electrospun carbon nanofibers (ECNFs) with a time‐dependent growth mechanism. This material also exhibits a new finding of mT magnetic field‐induced enhancement of the electron exchange number of the ORR at a glassy carbon electrode modified with the Co3O4/ECNFs catalyst. The magnetic susceptibility of the unpaired electrons in Co3O4 improves the kinetics and efficiency of electron transfer reactions in the ORR, which shows a 3.92‐electron pathway in the presence of a 1.32 mT magnetic field. This research presents a potential revolution of traditional electrocatalysis by simply applying an external magnetic field on metal oxides as a replacement for noble metals to reduce the risk of fuel‐cell degradation and maximize the energy output.
Use of split‐free nano‐liquid chromatography–mass spectrometry/high resolution mass spectrometry interface to improve the detection of α‐cobratoxin in equine plasma for doping control
Authors: Bailly‐Chouriberry Ludovic , Garcia Patrice , Cormant Florence , Loup Benoit , Popot Marie‐Agnès , Bonnaire Yves 
Published: December 2017

AbstractCobra (Naja naja kaouthia) venom contains a toxin called α‐cobratoxin (α‐Cbtx) containing 71 amino acids (MW 7821 Da) with a reported analgesic power greater than morphine. In 2013, the first analytical method for the detection of α‐Cbtx in equine plasma was developed by Bailly‐Chouriberry et al, allowing the confirmation of the presence of α‐Cbtx at low concentrations (1–5 ng/mL or 130–640 fmol/mL) in plasma samples. To increase the method sensitivity and therefore to improve the detection of α‐Cbtx in post‐administration plasma samples, a nano‐liquid chromatography–mass spectrometry/high resolution mass spectrometry (nLC–MS/HRMS) method was developed. This new method allowed us to confirm the presence of α‐Cbtx in plasma samples spiked at 100 pg/mL (12.8 fmol/mL) and the detection of α‐Cbtx was obtained in plasma samples collected 72 hours post‐administration (50 pg/mL or 6.4 fmol/mL) which was defined as the limit of detection (LOD). The presented method is 20‐fold more sensitive compared to the method previously described.
Is Didymosphenia geminata an introduced species in New Zealand? Evidence from trends in water chemistry, and chloroplast DNA
Authors: Kilroy Cathy , Novis Phil 
Published: December 2017

AbstractDefining the geographic origins of free‐living aquatic microorganisms can be problematic because many such organisms have ubiquitous distributions, and proving absence from a region is practically impossible. Geographic origins become important if microorganisms have invasive characteristics. The freshwater diatom Didymosphenia geminata is a potentially ubiquitous microorganism for which the recent global expansion of nuisance proliferations has been attributed to environmental change. The changes may include declines in dissolved reactive phosphorus (DRP) to low levels (e.g., <2 mg/m3) and increases in dissolved inorganic nitrogen (DIN) to >10 mg/m3 because both these nutrient conditions are associated with nuisance proliferations of D. geminata. Proliferations of D. geminata have been observed in South Island, New Zealand, since 2004. We aimed to address the ubiquity hypothesis for D. geminata in New Zealand using historical river water nutrient data and new molecular analyses. We used 15 years of data at 77 river sites to assess whether trends in DRP or DIN prior to the spread of D. geminata were consistent with a transition from a rare, undetected, species to a nuisance species. We used new sequences of chloroplast regions to examine the genetic similarity of D. geminata populations from New Zealand and six overseas locations. We found no evidence for declines in DRP concentrations since 1989 that could explain the spread of proliferations since 2004. At some affected sites, lowest DRP occurred before 2004. Trends in DIN also did not indicate enhanced suitability for D. geminata. Lack of diversity in the chloroplast intergenic regions of New Zealand populations and populations from western North America is consistent with recent dispersal to New Zealand. Our analyses did not support the proposal that D. geminata was historically present in New Zealand rivers. These results provide further evidence countering proposals of general ubiquity in freshwater diatoms and indicate that, as assumed in 2004, D. geminata is a recent arrival in New Zealand.
Prolonged dry periods between rainfall events shorten the growth period of the resurrection plant Reaumuria soongorica
Authors: Zhang Zhengzhong , Shan Lishan , Li Yi 
Published: December 2017

AbstractThe resurrection plant Reaumuria soongorica is widespread across Asia, southern Europe, and North Africa and is considered to be a constructive keystone species in desert ecosystems, but the impacts of climate change on this species in desert ecosystems are unclear. Here, the morphological responses of R. soongorica to changes in rainfall quantity (30% reduction and 30% increase in rainfall quantity) and interval (50% longer drought interval between rainfall events) were tested. Stage‐specific changes in growth were monitored by sampling at the beginning, middle, and end of the growing season. Reduced rainfall decreased the aboveground and total biomass, while additional precipitation generally advanced R. soongorica growth and biomass accumulation. An increased interval between rainfall events resulted in an increase in root biomass in the middle of the growing season, followed by a decrease toward the end. The response to the combination of increased rainfall quantity and interval was similar to the response to increased interval alone, suggesting that the effects of changes in rainfall patterns exert a greater influence than increased rainfall quantity. Thus, despite the short duration of this experiment, consequences of changes in rainfall regime on seedling growth were observed. In particular, a prolonged rainfall interval shortened the growth period, suggesting that climate change‐induced rainfall variability may have significant effects on the structure and functioning of desert ecosystems.
Minimum area thresholds for rattlesnakes and colubrid snakes on islands in the Gulf of California, Mexico
Authors: Meik Jesse M. , Makowsky Robert 
Published: December 2017

AbstractWe expand a framework for estimating minimum area thresholds to elaborate biogeographic patterns between two groups of snakes (rattlesnakes and colubrid snakes) on islands in the western Gulf of California, Mexico. The minimum area thresholds for supporting single species versus coexistence of two or more species relate to hypotheses of the relative importance of energetic efficiency and competitive interactions within groups, respectively. We used ordinal logistic regression probability functions to estimate minimum area thresholds after evaluating the influence of island area, isolation, and age on rattlesnake and colubrid occupancy patterns across 83 islands. Minimum area thresholds for islands supporting one species were nearly identical for rattlesnakes and colubrids (~1.7 km2), suggesting that selective tradeoffs for distinctive life history traits between rattlesnakes and colubrids did not result in any clear advantage of one life history strategy over the other on islands. However, the minimum area threshold for supporting two or more species of rattlesnakes (37.1 km2) was over five times greater than it was for supporting two or more species of colubrids (6.7 km2). The great differences between rattlesnakes and colubrids in minimum area required to support more than one species imply that for islands in the Gulf of California relative extinction risks are higher for coexistence of multiple species of rattlesnakes and that competition within and between species of rattlesnakes is likely much more intense than it is within and between species of colubrids.
Mapping multi‐scale vascular plant richness in a forest landscape with integrated LiDARand hyperspectral remote‐sensing
Authors: Hakkenberg C. R. , Zhu K. , Peet R. K. , Song C. 
Published: December 2017

AbstractThe central role of floristic diversity in maintaining habitat integrity and ecosystem function has propelled efforts to map and monitor its distribution across forest landscapes. While biodiversity studies have traditionally relied largely on ground‐based observations, the immensity of the task of generating accurate, repeatable, and spatially‐continuous data on biodiversity patterns at large scales has stimulated the development of remote‐sensing methods for scaling up from field plot measurements. One such approach is through integrated LiDARand hyperspectral remote‐sensing. However, despite their efficiencies in cost and effort, LiDAR‐hyperspectral sensors are still highly constrained in structurally‐ and taxonomically‐heterogeneous forests ‐ especially when species’ cover is smaller than the image resolution, intertwined with neighboring taxa, or otherwise obscured by overlapping canopy strata. In light of these challenges, this study goes beyond the remote characterization of upper canopy diversity to instead model total vascular plant species richness in a continuous‐cover North Carolina Piedmont forest landscape. We focus on two related, but parallel, tasks. First, we demonstrate an application of predictive biodiversity mapping, using nonparametric models trained with spatially‐nested field plots and aerial LiDAR‐hyperspectral data, to predict spatially‐explicit landscape patterns in floristic diversity across seven spatial scales between 0.01–900 m2. Second, we employ bivariate parametric models to test the significance of individual, remotely‐sensed predictors of plant richness to determine how parameter estimates vary with scale. Cross‐validated results indicate that predictive models were able to account for 15–70% of variance in plant richness, with LiDAR‐derived estimates of topography and forest structural complexity, as well as spectral variance in hyperspectral imagery explaining the largest portion of variance in diversity levels. Importantly, bivariate tests provide evidence of scale‐dependence among predictors, such that remotely‐sensed variables significantly predict plant richness only at spatial scales that sufficiently subsume geolocational imprecision between remotely‐sensed and field data, and best align with stand components including plant size and density, as well as canopy gaps and understory growth patterns. Beyond their insights into the scale‐dependent patterns and drivers of plant diversity in Piedmont forests, these results highlight the potential of remotely‐sensible essential biodiversity variables for mapping and monitoring landscape floristic diversity from air‐ and space‐borne platforms.
Cardiovascular magnetic resonance imaging and clinical performance of somatostatin receptor positron emission tomography in cardiac sarcoidosis
Authors: Pizarro Carmen , Kluenker Folke , Dabir Darius , Thomas Daniel , Gaertner Florian C. , Essler Markus , Grohé Christian , Nickenig Georg , Skowasch Dirk 
Published: December 2017

AbstractAimsCardiac affection constitutes a major limiting condition in systemic sarcoidosis. The primary objective of this study was to investigate the persistence rate of cardiac sarcoid involvement by cardiovascular magnetic resonance (CMR) imaging in patients diagnosed with cardiac sarcoidosis (CS). Moreover, we examined the additional insights into myocardial damage's characteristics gained by somatostatin receptor scintigraphy.Methods and resultsIn a pilot study, we had previously identified cardiac involvement—diagnosed by CMR imaging—to be present in 29 of 188 patients (15.4%) with histologically proven, extra‐CS. Out of these initial 29 CS‐positive patients, 27 patients (49.9 ± 11.8 years, 59.3% male) were presently re‐examined and underwent a second CMR study and complementary standard clinical testing. Somatostatin receptor scintigraphy using the ligand 68Ga‐DOTATOC was additionally performed when clinically indicated (17 patients). Within a median follow‐up period of 2.6 years, none of the initial 29 patients deceased or experienced aborted sudden cardiac death. However, two patients developed third‐degree atrioventricular block that required device therapy. Among the 27 re‐examined CS patients, pathological CMR findings persisted in 14 of 27 patients (51.9%). CS remission was primarily due to a resolution of acute inflammatory processes. 68Ga‐DOTATOC positron emission tomography/computed tomography (PET/CT) identified one patient with regions of raised tracer uptake that concorded with acute inflammatory changes, as assessed by CMR; this patient received no immunosuppressive medication at the time of PET/CT execution.ConclusionsWithin follow‐up, CS persisted in barely half the patients, and the patients were not afflicted with cardiac death. Additional 68Ga‐DOTATOC PET/CT allowed for visualization of acute myocardial inflammation.
The improvement of numerical modeling in the solution of incompressible viscous flow problems using finite element method based on spherical Hankel shape functions
Authors: Farmani Sajedeh , Ghaeini‐Hessaroeyeh Mahnaz , Javaran Saleh Hamzehei 
Published: December 2017

SummaryIn this paper, the finite element method with new spherical Hankel shape functions is developed for simulating 2‐dimensional incompressible viscous fluid problems. In order to approximate the hydrodynamic variables, the finite element method based on new shape functions is reformulated. The governing equations are the Navier‐Stokes equations solved by the finite element method with the classic Lagrange and spherical Hankel shape functions. The new shape functions are derived using the first and second kinds of Bessel functions. In addition, these functions have properties such as piecewise continuity. For the enrichment of Hankel radial basis functions, polynomial terms are added to the functional expansion that only employs spherical Hankel radial basis functions in the approximation. In addition, the participation of spherical Bessel function fields has enhanced the robustness and efficiency of the interpolation. To demonstrate the efficiency and accuracy of these shape functions, 4 benchmark tests in fluid mechanics are considered. Then, the present model results are compared with the classic finite element results and available analytical and numerical solutions. The results show that the proposed method, even with less number of elements, is more accurate than the classic finite element method.