bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorohalogenation of gem‐Difluoroalkenes: Synthesis and Applications of α‐Trifluoromethyl Halides
Authors: Liu Chi , Zhu Chuanle , Cai Yingying , Yang Zhiyi , Zeng Hao , Chen Fulin , Jiang Huanfeng 
Published: December 2019

AbstractA novel strategy for 1,2‐dihalogenation of alkenes is reported that occurs through a sequential nucleophilic halide addition and electrophilic halogenation. By trapping the in situ generated unstable α‐trifluoromethyl carbanion intermediates derived from the nucleophilic fluoride addition to electron‐poor gem‐difluoroalkenes, this fluorohalogenation of gem‐difluoroalkenes with electrophilic haloalkynes affords various useful α‐trifluoromethyl halides in high yields. A pesticidal active compound and various attractive trifluromethylated molecules could be smoothly synthesized from these obtained α‐trifluoromethyl halides.
Synthesis of Dual‐Responsive Materials with Reversible and Switchable Phase‐Transition Properties for High‐Performance Cellulose Enzymatic Hydrolysis
Authors: Zhu Xing , Tian Yi , He Bin , Gan Ting , Hu Xiao , Wang Xuechuan 
Published: December 2019

AbstractThe solid–solid (immobilized cellulase–insoluble cellulose) phase cellulose hydrolysis reaction is significant in cellulosic biomass conversion processes but hindered because of its low efficiency. Herein, a smart temperature–pH dual‐responsive material (D‐N‐N material) was prepared to be used as a carrier for cellulase recovery. This D‐N‐N material could undergo reversible and switchable transitions between solution, hydrogel, and solid phases. The following results were demonstrated: 1) the hydrolytic degree of this strategy could be as high as that of free cellulase in buffer solution; 2) the cellulase could be encapsulated into the D‐N‐N hydrogel without significant leaching and most of the cellulase activity was retained after recycling for at least 10 batches; and 3) more than 95 % of the glucose inside the hydrogel could be extracted during the hydrogel–solid transition within 1 h, which can assist in the high‐efficiency separation of cellulase from glucose. The results suggested that this strategy provides a feasible platform for efficient cellulose hydrolysis and could be applied to other bio‐derived reactions.
Pitfalls in drug testing by hyphenated low‐ and high‐resolution mass spectrometry
Authors: Maurer Hans H. 
Published: December 2019

AbstractThis paper reviews various pitfalls observed during developing, validation, application, and interpretation of drug testing approaches using GC–MS and low‐ and high‐resolution LC–MS. They include sampling and storage of body samples, sample adulteration and contamination, analyte stability, sample preparation without or with cleavage of conjugates, extraction, derivatization, internal standardization, false negative and positive results by GC–MS or LC–MS screening and/or confirmation procedures including artifact formation, ion suppression or enhancement by electrospray ionization, and finally pitfalls in data interpretation. Conclusions and prospects close the Tutorial.
Sensitivity of habitat hydraulic model outputs to DTM and computational mesh resolution
Authors: Papaioannou George , Papadaki Christina , Dimitriou Elias 
Published: December 2019

AbstractIn this study, a state‐of‐the‐art approach in modelling fish habitats, using high‐resolution topographical data, obtained from unmanned aerial vehicle, was applied. Habitat Suitability Indices are used to predict how changes in discharge affect instream fish habitats. Habitat Suitability Indices regarding depth and velocity for two size classes (small sized fish 5–15 cm total length and large sized >15 cm total length) of Salmo pelagonicus and Barbus balcanicus were used, in combination with a two‐dimensional hydraulic‐hydrodynamic model, for the estimation of the weighted usable area (WUA) in a mountainous stream. Computational mesh and/or digital terrain model (DTM) resolution selection may influence the accuracy of WUA results, especially in boulder and cobble‐bed streams with complex habitat structures. The aim of the study is to examine the sensitivity of various hydraulic‐hydrodynamic modelling geometry configurations on WUA at ungauged or poorly gauged streams. Comparisons of three different geometry configurations: (1) identical computational mesh and DTM resolution (SensComb); (2) finest computational mesh resolution combined with different DTM resolutions (SensDTM); (3) finest DTM resolution combined with different computational mesh resolutions, as part of two‐dimensional hydrodynamic modelling, were applied to test the differences in WUA (SensMesh). WUA maps were generated for both fish species and class sizes for each modelling geometry configuration and compared with each other for assessing the sensitivity of the two‐input data (computational mesh and DTM). Results provided by both indices and their spatial distribution indicated the optimal DTM and computational mesh resolution as well as the sensitivity of a specific hydraulic‐habitat model on them.
Local‐regional similarity in drylands increases during multiyear wet and dry periods and in response to extreme events
Authors: Petrie M. D. , Peters D. P. C. , Burruss N. D. , Ji W. , Savoy H. M. 
Published: December 2019

AbstractClimate change is predicted to impact ecosystems through altered precipitation (PPT) regimes. In the Chihuahuan Desert, multiyear wet and dry periods and extreme PPT pulses are the most influential climatic events for vegetation. Vegetation responses are most frequently studied locally, and regional responses are often unclear. We present an approach to quantify correlation of PPT and vegetation responses (as Normalized Difference Vegetation Index [NDVI]) at the Jornada ARS‐LTER site (JRN; 550 km2 area) and the surrounding dryland region (from 0 to 500 km distance; 400,000 km2 study area) as a way to understand regional similarity to locally observed patterns. We focused on fluctuating wet and dry years, multiyear wet or dry periods of 3–4 yr, and multiyear wet periods that contained one or more extreme high PPT pulses or extreme low rainfall. In all but extreme high PPT years, JRN PPT was highly correlated (r > 0.9) to PPT across the regional study area (0–500 km distance; high correlation from 25th to 75th percentiles) and was highly correlated across a greater PPT range subregionally (0–200 km distance; high correlation from 10th to 90th percentiles). In contrast, the statistical distribution of JRN NDVI was less similar to that of regional NDVI. Yet, local‐regional NDVI similarity increased during multiyear periods to a maximum of >90% similarity for 10th–90th percentiles in a number of years. Thus, local‐regional heterogeneity in PPT and vegetation responses is reduced in both multiyear wet and dry periods, with the largest changes in climatic forcing and responses during multiyear wet periods. These wet and dry events support greater similarity between local‐regional PPT and vegetation response patterns. We conclude that site‐based research on multiyear periods can be extended to anticipate larger regional responses, and illustrate the opportunity to enhance understanding of future PPT change through increased focus on multiyear periods.
Evidence for trait‐based community assembly patterns in hardwood hammock forests
Authors: Subedi Suresh C. , Hogan J. Aaron , Ross Michael S. , Sah Jay P. , Baraloto Christopher 
Published: December 2019

AbstractThe hardwood forests of south Florida, commonly referred to as hammocks, persist as well‐drained patches of broadleaf forest, embedded in a matrix of brackish water swamp, freshwater marsh, or pineland. Little is known about the patterns of community assembly of these subtropical forest communities in the landscape mosaic of south Florida. We used a functional trait approach to understand the composition of these communities and their responses to environmental variation across four areas of south Florida: the pine rocklands and freshwater marshes in Everglades National Park, and the lower and upper Florida Keys, where the hammocks are surrounded by halophytic swamp communities. These sites represent an environmental gradient from less‐productive, more xeric sites in the lower Florida Keys, to more‐productive, wetter sites in the Everglades marshes. We examined the patterns of trait variation at three levels (individual, population, and community) to examine the underlying processes driving assembly in these hammock communities. To understand processes governing community composition in each site, we used methods that partition variance in six traits (maximum tree height, specific leaf area, wood specific gravity, leaf nitrogen, leaf phosphorus, and leaf stable carbon isotope ratios) into internal and external filtering components. Community‐weighted mean trait values for three traits (specific leaf area, height, and leaf phosphorus) increased significantly from dry, less‐productive coastal sites in the Florida Keys to the moist, more‐productive areas on the mainland, while wood specific gravity and leaf δ13C showed the opposite pattern. For one or more traits per site, standardized effect sizes differed significantly from null expectation. Processes such as competition for resources (e.g., water, nutrients, light) and species sorting across microhabitats (i.e., within site) operate to increase local functional trait variation within communities and among species across sites. External filtering on individuals for height and leaf phosphorus differed significantly from null expectations across sites, while external filtering on species was only observed for specific leaf area, maximum tree height, and leaf phosphorus. These results are consistent with strong environmental filtering across the region, among local communities differing in freshwater accessibility or that occupy different positions along strong edaphic gradients. Our results confirm the importance of intraspecific variation among species and reflect a high degree of trait plasticity across the environmental gradient.
Life in a contaminant milieu: PPCP mixtures generate unpredictable outcomes across trophic levels and life stages
Authors: Parrish Samantha C. , Dormio Samantha M. , Richards Stephanie L. , McCoy Krista A. , McCoy Michael W. 
Published: December 2019

AbstractNearly all aquatic ecosystems are affected by sublethal levels of anthropogenic chemical contamination, but other agents of large‐scale anthropogenic disruption of ecosystems have received more attention. Consequently, ecologists do not fully appreciate how sublethal contaminant exposure affects ecosystems. Sublethal contaminants can affect ecological systems directly via their impacts on an organism's fitness or indirectly by changing the strengths of species interactions. This study investigated how an emerging class of contaminants—pharmaceuticals and personal care products (PPCPs)—influences food webs by affecting the biology of organisms and by interfering with predator–prey interactions. Specifically, we investigated how three common PPCPs—caffeine, DEET (N,N‐diethyl‐meta‐toluamide), and triclosan—affect the strength of the interaction between a common mosquito predator (i.e., mosquito fish) and mosquito larvae as well as how these PPCPS affect mosquito survival, life history traits, and oviposition site choices. We found that all three PPCPs, individually and combined as a mixture, reduced predator consumption rates. Relative to a contaminant‐free control, the presence of predator cues reduced mosquito oviposition and larval abundance for all PPCP treatments except for DEET. Predator cues reduced mosquito adult emergence across PPCP treatments; however, mosquitoes that were exposed to caffeine did not emerge as adults even in the absence of predator cues. This study shows that the effects of PPCPs are diverse and can interact with mosquitoes and their predators in ways that cannot be predicted by their individual effects. In a contaminated world, ecologists need to better understand how sublethal concentrations of ubiquitous, biologically active pollutants might challenge what we think we know about how ecological systems function.
Effects of Different Enzymatic Hydrolyses of Mutton Tallow on the Aroma Characteristics of the Maillard Reaction of Xylose–Cysteine Based on GC‐MS, E‐Nose, and Statistical Analysis
Authors: Ma Xueping , Zhan Ping , Tian Honglei , Wei Zhisheng , Wang Peng 
Published: December 2019

AbstractSolid‐phase micro extraction/gas chromatography‐mass spectrometry (SPME/GC‐MS), electronic nose (E‐nose), and descriptive sensory analysis (DSA) are used to evaluate the changes in aroma characteristic of six mutton tallow flavor (MF) samples prepared from xylose–cysteine with mutton tallow or different enzymatic hydrolysis mutton tallow (EM) with different enzymes. 61 compounds are identified by GC‐MS as crucial compounds contributing to the MF for the evaluation of the sensory characteristics of MFs. Most of the volatiles, including aldehydes, alcohols, furans, and thiophenes, decrease because of the addition of EMs. The EM with lipase MER produces more appropriate volatile compounds through the Maillard reaction than the other samples. Five attributes are selected for the appraisal of MFs. DSA results show a remarkable difference in sensory attributes among the MFs. MF5 has the strongest aroma in the muttony and meaty flavors, and the weakest in the burnt and off‐flavor. Further investigation of the six MFs is conducted based on the volatile compounds evaluated by E‐nose. The results of the correlation analysis among the volatile compounds and the DSA confirm that EM with lipase MER may be an appropriate precursor for MF's sensory characteristics.Practical Applications: Moderate lipid oxidation is a prerequisite to achieving a characteristic flavor. However, over‐treatment will lead to an undesirable smell. The thermal method requires high temperature and is difficult to control, and the resulting natural meat flavor needs improvement. A possible solution is to use enzymes to make a difference in the molecular weight of the enzymatically hydrolyzed fragments. To achieve controlled enzymatic hydrolysis of a fragment, the correct selection of enzyme is an important step. The present study helps elucidate how lipids contribute to the formation of meat flavor, thereby providing guidance for the preparation of thermal reaction meat flavor.
Pyrenyl Carbon Nanotubes for Covalent Bilirubin Oxidase Biocathode Design: Should the Nanotubes be Carboxylated?
Authors: Dharmaratne Asantha C. , Moulton James T. , Niroula Jinesh , Walgama Charuksha , Mazumder Suman , Mohanty Smita , Krishnan Sadagopan 
Published: December 2019

AbstractUnderstanding the characteristics of nanomaterials in the context of electrode designs for bio‐electrocatalysis is an emerging research direction. Applications for fuel cells, batteries, and biosensors are directly benefited. The objective of this study is to understand the influence of unfunctionalized multiwalled carbon nanotubes (MWNT) in comparison to carboxylated nanotubes (MWNT−COOH) for pi‐pi stacking with 1‐pyrenebutyric acid (Py) and covalent immobilization of bilirubin oxidase (BOD) enzyme toward the resulting oxygen reduction currents. We designed pyrolytic graphite‐edge electrodes modified with MWNT/Py, MWNT−COOH/Py, or only MWNT−COOH for carbodiimide activation and BOD immobilization. The relative increase in surface −COOH groups as we move from MWNT to MWNT/Py to MWNT−COOH/Py modification is voltammetrically estimated. Although the MWNT−COOH/Py displayed the highest relative amount of surface −COOH groups, the oxygen reduction current was the largest for the BOD‐immobilized MWNT/Py electrode than others. Results indicate that unfunctionalized MWNT is the optimal choice for pi‐pi stacking with pyrene linkers and covalent BOD immobilization as biocathode for energy devices. Favorable hydrophobic MWNT surface to interact more closely with the electron‐receiving T1 Cu site of BOD, as opposed to the relatively polar and more defective MWNT−COOH material due to functionalization, is suggested to be one of the underlying factors for the observed electrocatalytic trend.
Solution property preserving reconstruction for finite volume scheme: a boundary variation diminishing+multidimensional optimal order detection framework
Authors: Tann Siengdy , Deng Xi , Shimizu Yuya , Loubère Raphaël , Xiao Feng 
Published: December 2019

SummaryThe purpose of this work is to build a general framework to reconstruct the underlying fields within a finite volume (FV) scheme solving a hyperbolic system of PDEs (Partial Differential Equations). In an FV context, the data are piecewise constants per computational cell and the physical fields are reconstructed taking into account neighbor cell values. These reconstructions are further used to evaluate the physical states usually used to feed a Riemann solver which computes the associated numerical fluxes. The physical field reconstructions must obey some properties linked to the system of PDEs such as the positivity, but also some numerically based ones, like an essentially nonoscillatory behavior. Moreover, the reconstructions should be highly accurate for smooth flows and robust/stable for discontinuous solutions. To ensure a solution property preserving reconstruction, we introduce a methodology to blend high‐/low‐order polynomials and hyperbolic tangent reconstructions. A boundary variation diminishing algorithm is employed to select the best reconstruction in each cell. An a posteriori MOOD detection procedure is employed to ensure the positivity by recomputing the rare problematic cells using a robust first‐order FV scheme. We illustrate the performance of the proposed scheme via the numerical simulations for some benchmark tests which involve vacuum or near vacuum states, strong discontinuities, and also smooth flows. The proposed scheme maintains high accuracy on smooth profile, preserves the positivity and can eliminate the oscillations in the vicinity of discontinuities while maintaining sharper discontinuity with superior solution quality compared to classical highly accurate FV schemes.
Changes in chemical composition and biological activity of essential oil from Thomson navel orange (Citrus sinensis L. Osbeck) peel under freezing, convective, vacuum, and microwave drying methods
Authors: Farahmandfar Reza , Tirgarian Behraad , Dehghan Bahare , Nemati Azeeta 
Published: December 2019

AbstractThomson navel orange peel is a by‐product of citrus processing, which contains high levels of bioactive compounds advantageous to human health, nevertheless due to its high moisture content it is exceedingly perishable. Drying is among the most common preservation methods, which could prolong the plants shelf‐life via reducing their moisture value. Taking this into account, depending on their type and conditions, drying techniques could degrade plant heat‐sensitive metabolites and lead to quality decline. Therefore, the goal of this paper was to investigate the influence of seven drying methods named sun, shade, oven, vacuum oven, microwave, and freeze‐drying with different drying conditions on the physical properties, for example, bulk density and color (L*, a*, b*, ΔE, and browning index (BI)) and essential oil characteristics such as extraction yield, chemical composition, antioxidant (total phenolic content (TPC), DPPH, and FRAP essays), and antimicrobial (MIC and MBC) activities of Thomson peel and determine the superior drying procedure. Results showed that freeze‐dried sample had the highest retention of L* (48.54) and b* (49.00) values, lowest BI (216.11) as well as highest EO extraction yield (6.90%), TPC (60.10 GAE/100 g), FRAP (0.52% at 80 mg/ml), and lowest IC50 (5.00 mg/ml), MIC and MBC compared with other drying treatments. Therefore, it could be inferred that freeze‐drying is the most efficient drying approach in respect of preserving both physical and EO attributes of Thomson peel.
The determinants of performance in the Eurozone banking sector: Core versus periphery Eurozone economies
Authors: Agoraki Maria‐Eleni K. , Kouretas Georgios P. , Tsamis Anastassios 
Published: December 2019

AbstractIn the present study we provide a thorough analysis of the effects that a group of bank‐specific as well as industry‐specific determinants along with the regulatory framework developed under the three pillars of Basel II agreement (capital stringency, official disciplinary power and private monitoring) have on the performance of Eurozone banking sector over the period 2007–2016. To this end, we conduct a systematic comparative analysis of the determinants of the performance of the banking sector in periphery Eurozone countries (Greece, Italy, Portugal, Spain) versus banks operating in core Eurozone economies (Germany, France). We provide evidence that is consistent with the argument that banks financed with short‐run capital market funding are more fragile. A further finding of our analysis shows that banks operating in countries which have a more restrictive regulatory framework on banking activities perform better. In addition, it is shown that the better‐performing banks have more equity. Finally, the estimation of the appropriate dynamic models we argue that bank performance is affected by bank‐specific determinants like equity capital and bank size, while the regulatory framework as well as macroeconomic variables play a crucial role.
Response of stream fungi on decomposing leaves to experimental drying
Authors: Niyogi Dev K. , Hu Chia‐Yi , Vessell Brett P. 
Published: December 2019

AbstractClimate change may lead to increased droughts in the future, which in turn may lead to increased periods of stream drying. We conducted an experiment to test the effects of drying on fungal communities and microbial activity on decaying leaves from a stream. Our experimental setup included immersion of maple leaf cores for 2 weeks in a small stream to allow for the colonization of microbes. Leaves were then subjected for 2 weeks to four treatments: one control, where leaves stayed immersed in the stream, and three drying treatments in different settings (field, lab, and oven). Leaves were then returned to sterile water for 2 weeks of recovery. Microbial respiration declined after all drying treatments compared to the control, with the oven‐dried leaves taking the longest time to recover. All drying treatments had similar respiration to each other and the control after 2 weeks of immersion recovery. Fungal communities on the leaves were assessed by polymerase chain reaction amplification of fungal DNA from leaves followed by denaturing gradient gel electrophoresis (DGGE). Most treatments had very similar communities based on phylotypes from DGGE, with little change during drying and recovery compared to immersion controls. However, the oven‐dried leaves had a very different community developing during recovery. There were no differences in diversity or richness of DGGE phylotypes among treatments after recovery. Overall, the fungal communities, in our experiment, appeared resilient to the effects of short‐term drying, with little change to community structure and relatively fast recovery in activity after rewetting.