bluuebunny/crossref_metadata_2025_split huggingface dataset:
Catalytic Photoreduction Induced by Visible Light
Authors: Qiao Baokun , Jiang Zhiyong 
Published: June 2018

AbstractIn 1978, Kellogg et al. described photoreduction of sulfonium ions to the corresponding thioethers and alkanes with tertiary amines as the terminal reductant [Tetrahedron Lett., 1978, 19, 1255]. Since then, visible‐light‐driven photocatalysis, which enables the substrates to undergo an open‐shell single‐electron transfer to realize important transformations, has attracted significant research interest. Among the many methods inspired by this early report, photoreduction as an extension of Kellogg's work has received particular attention given its ability to provide an expedient and sustainable approach to access valuable compounds from readily accessible feedstocks. Furthermore, the development of distinct reductive procedures presented important foundations to develop other synthetic methodologies for the construction of natural and bioactive non‐natural molecules. In this Review, we will discuss advances in this significant research area. The examples are categorized by achiral and chiral reaction patterns with different kinds of starting substrates.
Effect of ultraviolet light treatment on surface hydrophilicity and human gingival fibroblast response on nanostructured titanium surfaces
Authors: Areid Nagat , Peltola Ari , Kangasniemi Ilkka , Ballo Ahmed , Närhi Timo O. 
Published: June 2018

AbstractThis study was designed to investigate the effect of nanostructured TiO2coatings on human gingival fibroblast and to explore the influence of ultraviolet (UV) light on surface wettability and cellular response. Ti‐6Al‐4V titanium alloy discs (n = 96) were divided into three groups: a sol–gel‐derived MetAlive™ (MA) coating; hydrothermal (HT) coating; and a non‐coated (NC) group. Forty‐eight titanium substrates were further treated with UV light for 15 min. The water contact angles of the substrates were measured using the sessile drop method. Human gingival fibroblasts were used to evaluate the cell adhesion strength and cell proliferation on experimental surfaces. The strength of cell adhesion against enzymatic detachment was studied after 6 hr of adhesion using gentle trypsinization for 15 min at room temperature. A fluorescence microscope was used for cell imaging (Zeiss‐stereo‐lumar‐v12), and images were analyzed for cell counting, and the percentage of detached cells were calculated. The proliferation of cultured cells up to 10 days was determined according to the cell activity using Alamar Blue™assay. The HT group had the lowest contact angle value (31.1°) followed by MetAlive™ (35.3°), whereas the NC group had the highest contact angle (50.3°). After UV light treatment, all surfaces become considerably more hydrophilic. There was a significant difference in the amount of adherent cells between sol–gel and HT groups when compared with the NC group (p < .05) with detachment percentages of 35.8%, 36.4%, and 70.7%, respectively. All substrate types showed an increase in cell proliferation rate until 10 days. It can be concluded that nanostructured titanium oxide implant surfaces, obtained by sol–gel and HT coating methods, enhance the surface wettability and improve human gingival fibroblast function in terms of adhesion and proliferation rate when compared with non‐coated surfaces. UV light treatment clearly enhances the wettability of all titanium surfaces.
Electrochemical Hydrogen Evolution Reaction Efficiently Catalyzed by Ru2P Nanoparticles
Authors: Wang Yuan , Liu Zong , Liu Hui , Suen Nian‐Tzu , Yu Xu , Feng Ligang 
Published: June 2018

AbstractDeveloping alternatives to Pt catalysts is a prerequisite to cost‐effectively produce hydrogen. Herein, we demonstrate Ru2P nanoparticles (without any doping and modifications) as a highly efficient Pt‐like catalyst for the hydrogen evolution reaction (HER) in different pH electrolytes. On transferring the hexagonal close‐packed crystal structure of Ru to the orthorhombic structure of Ru2P, a greatly improved catalytic activity and stability toward HER is found owing to Ru−P coordination. The electronic state change originates from the P−Ru bonding structures, which accounts for the HER activity improvement compared with Ru nanoparticles. Specifically, Ru2P nanoparticles can drive 10 mA cm−2 at a very low overpotential of 55 mV, only 8 mV more than Pt/C in an acidic solution; and an extremely low overpotential of approximately 50 mV is needed in alkaline solution, about 20 mV less than the Pt/C catalyst. The Volmer–Tafel mechanism is indicated on Ru2P nanoparticles with the typical Tafel slope of 30 mV dec−1 of Pt metal indicating a Pt‐like catalytic ability. Ru2P is more active in the Ru‐P family as H atoms prefer to adsorb on Ru atoms rather than on the P element according to theoretical calculations. Considering the low price of Ru (20 % of Pt), anti‐corrosion ability in the electrolyte, and the safe and reliable fabrication approach, the powder Ru2P nanoparticles make an excellent HER catalyst with great promise for large‐scale water electrolysis applications.
Genetic structure in Red Junglefowl (Gallus gallus) populations: Strong spatial patterns in the wild ancestors of domestic chickens in a core distribution range
Authors: Nguyen‐Phuc Hoa , Berres Mark E. 
Published: June 2018

AbstractRed Junglefowl (Gallus gallus) are among the few remaining ancestors of an extant domesticated livestock species, the domestic chicken, that still occur in the wild. Little is known about genetic diversity, population structure, and demography of wild Red Junglefowl in their natural habitats. Extinction threats from habitat loss or genetic alteration from domestic introgression exacerbate further the conservation status of this progenitor species. In a previous study, we reported extraordinary adaptive genetic variation in the MHC B‐locus in wild Red Junglefowl and no evidence of allelic introgression between wild and domestic chickens was observed. In this study, we characterized spatial genetic variation and population structure in naturally occurring populations of Red Junglefowl in their core distribution range in South Central Vietnam. A sample of 212 Red Junglefowl was obtained from geographically and ecologically diverse habitats across an area of 250 × 350 km. We used amplified fragment‐length polymorphism markers obtained from 431 loci to determine whether genetic diversity and population structure varies. We found that Red Junglefowl are widely distributed but form small and isolated populations. Strong spatial genetic patterns occur at both local and regional scales. At local scale, population stratification can be identified to approximately 5 km. At regional scale, we identified distinct populations of Red Junglefowl in the southern lowlands, northern highlands, and eastern coastal portions of the study area. Both local and long‐distance genetic patterns observed in wild Red Junglefowl may reflect the species’ ground‐dwelling and territorial characteristics, including dispersal barriers imposed by the Annamite Mountain Range. Spatially explicit analyses with neutral genetic markers can be highly informative and here elevates the conservation profile of the wild ancestors of domesticated chickens.
Not attackable or not crackable—How pre‐ and post‐attack defenses with different competition costs affect prey coexistence and population dynamics
Authors: Ehrlich Elias , Gaedke Ursula 
Published: June 2018

AbstractIt is well‐known that prey species often face trade‐offs between defense against predation and competitiveness, enabling predator‐mediated coexistence. However, we lack an understanding of how the large variety of different defense traits with different competition costs affects coexistence and population dynamics. Our study focusses on two general defense mechanisms, that is, pre‐attack (e.g., camouflage) and post‐attack defenses (e.g., weaponry) that act at different phases of the predator—prey interaction. We consider a food web model with one predator, two prey types and one resource. One prey type is undefended, while the other one is pre‐ or post‐attack defended paying costs either by a higher half‐saturation constant for resource uptake or a lower maximum growth rate. We show that post‐attack defenses promote prey coexistence and stabilize the population dynamics more strongly than pre‐attack defenses by interfering with the predator's functional response: Because the predator spends time handling “noncrackable” prey, the undefended prey is indirectly facilitated. A high half‐saturation constant as defense costs promotes coexistence more and stabilizes the dynamics less than a low maximum growth rate. The former imposes high costs at low resource concentrations but allows for temporally high growth rates at predator‐induced resource peaks preventing the extinction of the defended prey. We evaluate the effects of the different defense mechanisms and costs on coexistence under different enrichment levels in order to vary the importance of bottom‐up and top‐down control of the prey community.
Double‐digest RADseq loci using standard Illumina indexes improve deep and shallow phylogenetic resolution of Lophodermium, a widespread fungal endophyte of pine needles
Authors: Salas‐Lizana Rodolfo , Oono Ryoko 
Published: June 2018

AbstractThe phylogenetic and population genetic structure of symbiotic microorganisms may correlate with important ecological traits that can be difficult to directly measure, such as host preferences or dispersal rates. This study develops and tests a low‐cost double‐digest restriction site‐associated DNA sequencing (ddRADseq) protocol to reveal among‐ and within‐species genetic structure for Lophodermium, a genus of fungal endophytes whose evolutionary analyses have been limited by the scarcity of informative markers. The protocol avoids expensive barcoded adapters and incorporates universal indexes for multiplexing. We tested for reproducibility and functionality by comparing shared loci from sample replicates and assessed the effects of numbers of ambiguous sites and clustering thresholds on coverage depths, number of shared loci among samples, and phylogenetic reconstruction. Errors between technical replicates were minimal. Relaxing the quality‐filtering criteria increased the mean coverage depth per locus and the number of loci recovered within a sample, but had little effect on the number of shared loci across samples. Increasing clustering threshold decreased the mean coverage depth per cluster and increased the number of loci recovered within a sample but also decreased the number of shared loci across samples, especially among distantly related species. The combination of low similarity clustering (70%) and relaxed quality‐filtering (allowing up to 30 ambiguous sites per read) performed the best in phylogenetic analyses at both recent and deep genetic divergences. Hence, this method generated sufficient number of shared homologous loci to investigate the evolutionary relationships among divergent fungal lineages with small haploid genomes. The greater genetic resolution also revealed new structure within species that correlated with ecological traits, providing valuable insights into their cryptic life histories.
Turnover in local parasite populations temporarily favors host outcrossing over self‐fertilization during experimental evolution
Authors: Lynch Zachary R. , Penley McKenna J. , Morran Levi T. 
Published: June 2018

AbstractThe ubiquity of outcrossing in plants and animals is difficult to explain given its costs relative to self‐fertilization. Despite these costs, exposure to changing environmental conditions can temporarily favor outcrossing over selfing. Therefore, recurring episodes of environmental change are predicted to favor the maintenance of outcrossing. Studies of host–parasite coevolution have provided strong support for this hypothesis. However, it is unclear whether multiple exposures to novel parasite genotypes in the absence of coevolution are sufficient to favor outcrossing. Using the nematode Caenorhabditis elegans and the bacterial parasite Serratia marcescens, we studied host responses to parasite turnover. We passaged several replicates of a host population that was well‐adapted to the S. marcescens strain Sm2170 with either Sm2170 or one of three novel S. marcescens strains, each derived from Sm2170, for 18 generations. We found that hosts exposed to novel parasites maintained higher outcrossing rates than hosts exposed to Sm2170. Nonetheless, host outcrossing rates declined over time against all but the most virulent novel parasite strain. Hosts exposed to the most virulent novel strain exhibited increased outcrossing rates for approximately 12 generations, but did not maintain elevated levels of outcrossing throughout the experiment. Thus, parasite turnover can transiently increase host outcrossing. These results suggest that recurring episodes of parasite turnover have the potential to favor the maintenance of host outcrossing. However, such maintenance may require frequent exposure to novel virulent parasites, rapid rates of parasite turnover, and substantial host gene flow.
Attracting Common Carp to a bait site with food reveals strong positive relationships between fish density, feeding activity, environmental DNA, and sex pheromone release that could be used in invasive fish management
Authors: Ghosal Ratna , Eichmiller Jessica J. , Witthuhn Bruce A. , Sorensen Peter W. 
Published: June 2018

AbstractMeasurement of environmental DNA (eDNA) is becoming a common technique to survey for rare and invasive fish due to its sensitivity and specificity. However, its utility is limited by an incomplete understanding of factors governing its sources and fates. Failure to detect eDNA is especially difficult to interpret so surveillance techniques often collect large numbers of samples across broad regions. If, however, fish could be reliably attracted to a single location where their eDNA could be easily measured that would be useful. We conducted a proof‐of‐concept study of this idea using invasive Common Carp. We monitored the distribution of radio‐tagged Carp and their eDNA across a 67 ha lake focusing at the bait site while a pheromone (Prostaglandin F2α; PGF2α) was also measured to determine their reproductive condition. Prior to baiting, Carp were patchily distributed and while eDNA was occasionally detectable, it was patchy and only loosely associated with moderately dense groups of fish. Further, neither Carp, nor their eDNA were consistently measurable at the bait site and surrounding region, and the pheromone was not measurable at all. However, once baiting commenced, Carp started visiting the bait site and feeding, especially at night, where eDNA levels increased 500‐fold as fish densities doubled and PGF2α became detectable. Fish presence, eDNA and pheromone concentrations peaked at night after 6 days, strongly suggesting feeding activity was the main driver. While the presence of eDNA precisely coincided with this aggregation, levels had dropped dramatically within 5 m. PGF2α levels dropped less rapidly and demonstrated the presence of live mature fish. We suggest that food could be used to train fish to come to locations where they otherwise are too scarce to be reliably measured, increasing their eDNA release, making them measurable, and their reproductive condition also discernable by measuring pheromones.
Impact of ecological redundancy on the performance of machine learning classifiers in vegetation mapping
Authors: Macintyre Paul D. , Van Niekerk Adriaan , Dobrowolski Mark P. , Tsakalos James L. , Mucina Ladislav 
Published: June 2018

AbstractVegetation maps are models of the real vegetation patterns and are considered important tools in conservation and management planning. Maps created through traditional methods can be expensive and time‐consuming, thus, new more efficient approaches are needed. The prediction of vegetation patterns using machine learning shows promise, but many factors may impact on its performance. One important factor is the nature of the vegetation–environment relationship assessed and ecological redundancy. We used two datasets with known ecological redundancy levels (strength of the vegetation–environment relationship) to evaluate the performance of four machine learning (ML) classifiers (classification trees, random forests, support vector machines, and nearest neighbor). These models used climatic and soil variables as environmental predictors with pretreatment of the datasets (principal component analysis and feature selection) and involved three spatial scales. We show that the ML classifiers produced more reliable results in regions where the vegetation–environment relationship is stronger as opposed to regions characterized by redundant vegetation patterns. The pretreatment of datasets and reduction in prediction scale had a substantial influence on the predictive performance of the classifiers. The use of ML classifiers to create potential vegetation maps shows promise as a more efficient way of vegetation modeling. The difference in performance between areas with poorly versus well‐structured vegetation–environment relationships shows that some level of understanding of the ecology of the target region is required prior to their application. Even in areas with poorly structured vegetation–environment relationships, it is possible to improve classifier performance by either pretreating the dataset or reducing the spatial scale of the predictions.
Effects of patch size and basal area on avian taxonomic and functional diversity in pine forests: Implication for the influence of habitat quality on the species–area relationship
Authors: Lee Myung‐Bok , Carroll John P. 
Published: June 2018

AbstractRelationships between avian diversity and habitat area are assumed to be positive; however, often little attention has given to how these relationships can be influenced by the habitat structure or quality. In addition, other components of biodiversity, such as functional diversity, are often overlooked in assessing habitat patch value. In the Sandhills Ecoregion of Georgia, USA, we investigated the relationship between avian species richness and functional diversity, forest basal area, and patch size in pine forests using basal area as a surrogate for overstory structure which in turn impacts vegetation structure and determines habitat quality within a patch. We conducted bird surveys in planted mature pine stands, during breeding season of 2011. We used three classes of stand basal area (BA): OS, overstocked (BA ≥ 23 m2/ha); FS, fully/densely stocked (13.8 m2/ha ≤ BA < 23 m2/ha); and MS, moderately stocked (2.3 m2/ha ≤ BA < 13.8 m2/ha). MS patches showed more structural diversity due to higher herbaceous vegetation cover than other two pine stocking classes of patches. Total species richness and functional richness increased with the size of MS patches, whereas functional divergence decreased with the size of OS patches (p < 0.05). Functional richness tended to be lower than expected as the size of OS patches increased. Greater richness of pine–grassland species was also found at MS patches. Percent cover of MS patches within a landscape influenced positively the richness of pine–grassland species (p < 0.05). Our results suggest that (a) avian species–habitat area relationship can be affected by habitat quality (structural diversity) and varies depending on diversity indices considered, and (b) it is important to maintain moderate or low levels of pine basal area and to preserve large‐sized patches of the level of basal area to enhance both taxonomic and functional diversity in managed pine forests.
Reciprocal intraguild predation and predator coexistence
Authors: Marques Renata Vieira , Sarmento Renato Almeida , Oliveira Adriana Gonçalves , Rodrigues Diego de Macedo , Venzon Madelaine , Pedro‐Neto Marçal , Pallini Angelo , Janssen Arne 
Published: June 2018

AbstractIntraguild predation is a mix of competition and predation and occurs when one species feeds on another species that uses similar resources. Theory predicts that intraguild predation hampers coexistence of species involved, but it is common in nature. It has been suggested that increasing habitat complexity and the presence of alternative food may promote coexistence. Reciprocal intraguild predation limits possibilities for coexistence even further. Habitat complexity and the presence of alternative food are believed to promote coexistence. We investigated this using two species of predatory mites, Iphiseiodes zuluagai and Euseius concordis, by assessing co‐occurrence in the field and on arenas differing in spatial structure in the laboratory. The predators co‐occured on the same plants in the field. In the laboratory, adults of the two mites fed on juveniles of the other species, both in the presence and the absence of a shared food source, showing that the two species are involved in reciprocal intraguild predation. Adults of I. zuluagai also attacked adults of E. concordis. This suggests limited possibilities for coexistence of the two species. Indeed, E. concordis invariably went extinct extremely rapidly on arenas without spatial structure with populations consisting of all stages of the two predators and with a shared resource. Coexistence was prolonged on host plant leaves with extra food sources, but E. concordis still went extinct. On small, intact plants, coexistence of the two species was much longer, and ended with the other species, I. zuluagai, often going extinct. These results suggest that spatial structure and the presence of alternative food increase the coexistence period of intraguild predators.
MicroWeaR: A new R package for dental microwear analysis
Authors: Strani Flavia , Profico Antonio , Manzi Giorgio , Pushkina Diana , Raia Pasquale , Sardella Raffaele , DeMiguel Daniel 
Published: June 2018

AbstractMastication of dietary items with different mechanical properties leaves distinctive microscopic marks on the surface of tooth enamel. The inspection of such marks (dental microwear analysis) is informative about the dietary habitus in fossil as well as in modern species. Dental microwear analysis relies on the morphology, abundance, direction, and distribution of these microscopic marks. We present a new freely available software implementation, MicroWeaR, that, compared to traditional dental microwear tools, allows more rapid, observer error free, and inexpensive quantification and classification of all the microscopic marks (also including for the first time different subtypes of scars). Classification parameters and graphical rendering of the output are fully settable by the user. MicroWeaR includes functions to (a) sample the marks, (b) classify features into categories as pits or scratches and then into their respective subcategories (large pits, coarse scratches, etc.), (c) generate an output table with summary information, and (d) obtain a visual surface‐map where marks are highlighted. We provide a tutorial to reproduce the steps required to perform microwear analysis and to test tool functionalities. Then, we present two case studies to illustrate how MicroWeaR works. The first regards a Miocene great ape obtained from through environmental scanning electron microscope, and other a Pleistocene cervid acquired by a stereomicroscope.