bluuebunny/crossref_metadata_2025_split huggingface dataset:
Benzoylguanidines as Anion‐Responsive Systems
Authors: Glasovac Zoran , Barešić Luka , Antol Ivana , Margetić Davor 
Published: July 2018

AbstractA series of benzoylguanidinium salts was prepared and the changes in UV/Vis spectra, triggered by the presence of anions, were investigated. All compounds undergo deprotonation with basic anions like dihydrogenphosphate and acetate in acetonitrile. The most pronounced spectral changes were obtained by deprotonation of N1‐benzoyl‐N3‐(p‐nitrophenyl) guanidinium chloride which shows the naked‐eye visible color change from colorless to yellow. Measured pKa(BH+) in acetonitrile ranges from 12–16, which is comparable to the pyridinium cations. The proton transfer equilibria were also tested in acetonitrile/water mixture where all but the most acidic derivatives showed pKa(BH+) of 4–6 units which corresponds to apparent association constants of 104–106 dm3 mol−1. UV/Vis spectra of neutral and protonated forms were modelled by the TD‐DFT approach using CAM‐B3LYP and PBE0 functionals and compared to CC2 results. In the case of CAM‐B3LYP, a parameter ω, defining amount of long‐range exchange correction, was varied to achieve the best agreement with the experimental spectra. The optimized ω parameters are 0.10 a0−1 for neutral benzoylguanidines and 0.20 a0−1 for neutral nitrobenzoyl and protonated systems. The larger ω parameter in the latter is ascribed to more pronounced charge transfer character of the HOMO‐LUMO transition – the one responsible for the lowest energy absorption band.
A PK/PD Analysis of Circulating Biomarkers and Their Relationship to Tumor Response in Atezolizumab‐Treated non‐small Cell Lung Cancer Patients
Authors: Netterberg Ida , Li Chi‐Chung , Molinero Luciana , Budha Nageshwar , Sukumaran Siddharth , Stroh Mark , Jonsson E. Niclas , Friberg Lena E. 
Published: July 2018

To assess circulating biomarkers as predictors of antitumor response to atezolizumab (anti‐programmed death‐ligand 1 (PD‐L1), Tecentriq) serum pharmacokinetic (PK) and 95 plasma biomarkers were analyzed in 88 patients with relapsed/refractory non‐small cell lung cancer (NSCLC) receiving atezolizumab i.v. q3w (10–20 mg/kg) in the PCD4989g phase I clinical trial. Following exploratory analyses, two plasma biomarkers were chosen for further study and correlation with change in tumor size (the sum of the longest diameter) was assessed in a pharmacokinetic/pharmacodynamic (PK/PD) tumor modeling framework. When longitudinal kinetics of biomarkers and tumor size were modeled, tumor shrinkage was found to significantly correlate with area under the curve (AUC), baseline factors (metastatic sites, liver metastases, and smoking status), and relative change in interleukin (IL)‐18 level from baseline at day 21 (RCFBIL‐18,d21). Although AUC was a major predictor of tumor shrinkage, the effect was estimated to dissipate with an average half‐life of 80 days, whereas RCFBIL‐18,d21 seemed relevant to the duration of the response.
Island biogeography and ecological modeling of the amblypygid Phrynus marginemaculatus in the Florida Keys archipelago
Authors: Chapin Kenneth J. , Winkler Daniel E. , Wiencek Patrick , Agnarsson Ingi 
Published: July 2018

AbstractAimThe biogeography of terrestrial organisms across the Florida Keys archipelago is poorly understood. We used population genetics and spatioecological modeling of the Amblypygi Phrynus marginemaculatus to understand the genetic structure and metapopulation dynamics of Keys populations that are otherwise isolated by human development and ocean.LocationThe Florida Keys archipelago and mainland Florida.MethodsWe sequenced a 1,238 bp fragment of mtDNA for 103 individuals of P. marginemaculatus from 13 sites in the Florida Keys and South Florida, binned into four regions. We used population genetic analyses to understand the population structure of the species throughout its US range. Furthermore, we used ecological modeling with climate, habitat, and human development data to develop habitat suitability estimates for the species.ResultsWe found clear genetic structure between localities. The Lower Keys, in particular, support populations separate from those in other regions studied. Ecological modeling and genetic analyses showed the highest habitat suitability and genetic isolation in the Lower Keys, but urban development across the species range has resulted in the loss of most historical habitat.Main conclusionsA mainland‐metapopulation model best fits P. marginemaculatus gene flow patterns in the Florida Keys and mainland. Ocean currents likely play a role in metapopulation dynamics and gene flow for terrestrial Keys species like P. marginemaculatus, and genetic patterns also matched patterns consistent with geologic history. Suitable habitat, however, is limited and under threat of human destruction. The few remaining pockets of the most suitable habitat tend to occur in parks and protected areas. We argue that conservation efforts for this species and others in the terrestrial Florida Keys would benefit from a deeper understanding of the population genetic structure and ecology of the archipelago.
Flyway structure in the circumpolar greater white‐fronted goose
Authors: Wilson Robert E. , Ely Craig R. , Talbot Sandra L. 
Published: July 2018

AbstractDispersal and migratory behavior are influential factors in determining how genetic diversity is distributed across the landscape. In migratory species, genetic structure can be promoted via several mechanisms including fidelity to distinct migratory routes. Particularly within North America, waterfowl management units have been delineated according to distinct longitudinal migratory flyways supported by banding data and other direct evidence. The greater white‐fronted goose (Anser albifrons) is a migratory waterfowl species with a largely circumpolar distribution consisting of up to six subspecies roughly corresponding to phenotypic variation. We examined the rangewide population genetic structure of greater white‐fronted geese using mtDNA control region sequence data and microsatellite loci from 23 locales across North America and Eurasia. We found significant differentiation in mtDNA between sampling locales with flyway delineation explaining a significant portion of the observed genetic variation (~12%). This is concordant with band recovery data which shows little interflyway or intercontinental movements. However, microsatellite loci revealed little genetic structure suggesting a panmictic population across most of the Arctic. As with many high‐latitude species, Beringia appears to have played a role in the diversification of this species. A common Beringian origin of North America and Asian populations and a recent divergence could at least partly explain the general lack of structure at nuclear markers. Further, our results do not provide strong support for the various taxonomic proposals for this species except for supporting the distinctness of two isolated breeding populations within Cook Inlet, Alaska (A. a. elgasi) and Greenland (A. a. flavirostris), consistent with their subspecies status.
Changing environmental gradients over forty years alter ecomorphological variation in Guadalupe Bass Micropterus treculii throughout a river basin
Authors: Pease Jessica E. , Grabowski Timothy B. , Pease Allison A. , Bean Preston T. 
Published: July 2018

AbstractUnderstanding the degree of intraspecific variation within and among populations is a key aspect of predicting the capacity of a species to respond to anthropogenic disturbances. However, intraspecific variation is usually assessed at either limited temporal, but broad spatial scales or vice versa, which can make assessing changes in response to long‐term disturbances challenging. We evaluated the relationship between the longitudinal gradient of changing flow regimes and land use/land cover patterns since 1980 and morphological variation of Guadalupe Bass Micropterus treculii throughout the Colorado River Basin of central Texas. The Colorado River Basin in Texas has experienced major alterations to the hydrologic regime due to changing land‐ and water‐use patterns. Historical collections of Guadalupe Bass prior to rapid human‐induced change present the unique opportunity to study the response of populations to varying environmental conditions through space and time. Morphological differentiation of Guadalupe Bass associated with temporal changes in flow regimes and land use/land cover patterns suggests that they are exhibiting intraspecific trait variability, with contemporary individuals showing increased body depth, in response to environmental alteration through time (specifically related to an increase in herbaceous land cover, maximum flows, and the number of low pulses and high pulses). Additionally, individuals from tributaries with increased hydrologic alteration associated with urbanization or agricultural withdrawals tended to have a greater distance between the anal and caudal fin. These results reveal trait variation that may help to buffer populations under conditions of increased urbanization and sprawl, human population growth, and climate risk, all of which impose novel selective pressures, especially on endemic species like Guadalupe Bass. Our results contribute an understanding of the adaptability and capacity of an endemic population to respond to expected future changes based on demographic or climatic projection.
From dispersal to predation: A global synthesis of ant–seed interactions
Authors: Penn Hannah J. , Crist Thomas O. 
Published: July 2018

AbstractAnt–seed interactions take several forms, including dispersal, predation, and parasitism, whereby ants consume seed appendages without dispersal of seeds. We hypothesized that these interaction outcomes could be predicted by ant and plant traits and habitat, with outcomes falling along a gradient of cost and benefit to the plant. To test this hypothesis, we conducted a global literature review and classified over 6,000 pairs of ant–seed interactions from 753 studies across six continents. Linear models showed that seed and ant size, habitat, and dispersal syndrome were the most consistent predictors. Predation was less likely than parasitism and seed dispersal among myrmecochorous plants. A classification tree of the predicted outcomes from linear models revealed that dispersal and predation formed distinct categories based on habitat, ant size, and dispersal mode, with parasitism outcomes forming a distinct subgroup of predation based on seed size and shape. Multiple correspondence analysis indicated some combinations of ant genera and plant families were strongly associated with particular outcomes, whereas other ant–seed combinations were much more variable. Taken together, these results demonstrate that ant and plant traits are important overall predictors of potential seed fates in different habitat types.
Unexpected prey of juvenile spotted scat (Scatophagus argus) near a wharf: The prevalence of fouling organisms in stomach contents
Authors: Lin Xianzhi , Hu Simin , Liu Sheng , Huang Hui 
Published: July 2018

AbstractA knowledge of fish diets can contribute to revealing the trophic role and ecological function of species in aquatic ecosystems. At present, however, there are no efficient or comprehensive methods for analyzing fish diets. In this study, we investigated the diets of juvenile Scatophagus argus collected near a wharf in Daya Bay, China, by dissection and high‐throughput sequencing (HTS) using the 18S rDNA V4 region. Microscopy disclosed large amounts of bryozoans and unrecognizable detritus. In contrast, HTS analysis indicated that the fish diets were considerably more diverse than visual inspection suggested. After eliminating fish sequences, approximately 17,000 sequences from taxa in nine phyla (Ciliophora, Bryozoa, Annelida, Bacillariophyta, Chlorophyta, Arthropoda, Dinoflagellata, Tunicata, and Phaeophyta) were identified from the analysis of stomach contents. Twenty‐one food categories were identified, most of which (95.2%) were benthic fouling organisms that could easily be collected around wharfs. These consisted of bryozoans (31.9%), ciliates (45.7%), polychaetes (14.6%), and green algae (3.0%). Therefore, to adapt to anthropogenic habitat modification, the fish had probably shifted from planktonic to benthic feeding. The prevalence of fouling organisms in the stomachs of juvenile S. argus indicates that the fish have responded to habitat changes by widening their food spectrum. This adaptation may have increased their chances of survival. The fouling organisms that inhabit highly perturbed coastal ecosystems could represent a food source for animals at higher trophic levels. Our results accordingly suggest that human activity might significantly influence fish feeding behavior and material transfer along the food chain.
Root exudation rate as functional trait involved in plant nutrient‐use strategy classification
Authors: Guyonnet Julien P. , Cantarel Amélie A. M. , Simon Laurent , Haichar Feth el Zahar 
Published: July 2018

AbstractPlants adopt a variety of life history strategies to succeed in the Earth's diverse environments. Using functional traits which are defined as “morphological, biochemical, physiological, or phonological” characteristics measurable at the individual level, plants are classified according to their species’ adaptative strategies, more than their taxonomy, from fast growing plant species to slower‐growing conservative species. These different strategies probably influence the input and output of carbon (C)‐resources, from the assimilation of carbon by photosynthesis to its release in the rhizosphere soil via root exudation. However, while root exudation was known to mediate plant‐microbe interactions in the rhizosphere, it was not used as functional trait until recently. Here, we assess whether root exudate levels are useful plant functional traits in the classification of plant nutrient‐use strategies and classical trait syndromes? For this purpose, we conducted an experiment with six grass species representing along a gradient of plant resource‐use strategies, from conservative species, characterized by low biomass nitrogen (N) concentrations and a long lifespans, to exploitative species, characterized by high rates of photosynthesis and rapid rates of N acquisition. Leaf and root traits were measured for each grass and root exudate rate for each planted soil sample. Classical trait syndromes in plant ecology were found for leaf and root traits, with negative relationships observed between specific leaf area and leaf dry matter content or between specific root length and root dry matter content. However, a new root trait syndrome was also found with root exudation levels correlating with plant resource‐use strategy patterns, specifically, between root exudation rate and root dry matter content. We therefore propose root exudation rate can be used as a key functional trait in plant ecology studies and plant strategy classification.
Rainfall seasonality and drought performance shape the distribution of tropical tree species in Ghana
Authors: Amissah Lucy , Mohren Godefridus M. J. , Kyereh Boateng , Agyeman Victor K. , Poorter Lourens 
Published: July 2018

AbstractTree species distribution in lowland tropical forests is strongly associated with rainfall amount and distribution. Not only plant water availability, but also irradiance, soil fertility, and pest pressure covary along rainfall gradients. To assess the role of water availability in shaping species distribution, we carried out a reciprocal transplanting experiment in gaps in a dry and a wet forest site in Ghana, using 2,670 seedlings of 23 tree species belonging to three contrasting rainfall distributions groups (dry species, ubiquitous species, and wet species). We evaluated seasonal patterns in climatic conditions, seedling physiology and performance (survival and growth) over a 2‐year period and related seedling performance to species distribution along Ghana's rainfall gradient. The dry forest site had, compared to the wet forest, higher irradiance, and soil nutrient availability and experienced stronger atmospheric drought (2.0 vs. 0.6 kPa vapor pressure deficit) and reduced soil water potential (−5.0 vs. −0.6 MPa soil water potential) during the dry season. In both forests, dry species showed significantly higher stomatal conductance and lower leaf water potential, than wet species, and in the dry forest, dry species also realized higher drought survival and growth rate than wet species. Dry species are therefore more drought tolerant, and unlike the wet forest species, they achieve a home advantage. Species drought performance in the dry forest relative to the wet forest significantly predicted species position on the rainfall gradient in Ghana, indicating that the ability to grow and survive better in dry forests and during dry seasons may allow species to occur in low rainfall areas. Drought is therefore an important environmental filter that influences forest composition and dynamics. Currently, many tropical forests experience increase in frequency and intensity of droughts, and our results suggest that this may lead to reduction in tree productivity and shifts in species distribution.
Optimization of tea‐leaf saponins water extraction and relationships between their contents and tea (Camellia sinensis) tree varieties
Authors: Yu Xiao‐Lan , He Yong 
Published: July 2018

AbstractResulting from the year‐on‐year increase in tea plantations and the saturated consumption of tea leaves, the relative overcapacity in China's tea‐leaf production appears. Discovering the new utilization of tea leaves is helpful to alleviate this phenomenon. The feasibility of extracting saponins from aged tea leaves was investigated and confirmed; three major variables in water extraction were optimized by Box‐Behnken designs. The significant variable found in Box‐Behnken designs, liquid–solid ratio, was went through single‐variable experiments for a more accurate optimization. Seventy‐five ml/g, 1 hr, and 80°C were optimal values and tea‐leaf saponins yield of tea tree variety Longjing 43 reached 12.19% ± 0.0030% after optimizations, higher than the yield of tea‐seed saponins from Camellia oleifera seed meals using the same extraction method (water extraction based on optimizations). According to correlation analyses, tea tree's leaf type and germination stage affected tea‐leaf saponins contents positively, indicating tea trees with larger leaves and later germination stage would have a higher content of tea‐leaf saponins with a higher yield of tea‐leaf saponins under the same extraction method.
Doppler and biochemical assessment for the prediction of early pregnancy outcome in patients experiencing threatened spontaneous abortion
Authors: Shehata Nesreen A.A. , Ali Hamada A.A. , Hassan Abd El Gany M.A. , Katta Maha A. , Ali Ashraf S.F. 
Published: July 2018

AbstractObjectiveTo evaluate the usefulness of Doppler indices of the corpus luteum and uterine artery in combination with serum progesterone and cancer antigen 125 (CA125) as prognostic tools in first‐trimester threatened spontaneous abortion.MethodsPregnant women with threatened spontaneous abortion at a pregnancy duration 8–10 weeks were enrolled into an observational prospective clinical trial at a university hospital in Egypt during 2015. Doppler indices (uterine artery/corpus luteum resistance index and pulsatility index) and biochemical markers (CA125, progesterone) were determined and compared by pregnancy outcome (spontaneous abortion vs continuing pregnancy at 20 weeks).ResultsOf 100 women included, 16 had a spontaneous abortion. These women had a higher CA125 value than did women without an abortion (P<0.001), whereas the progesterone level among women with an abortion was lower (P<0.001). The Doppler indices were not significantly different between the groups, but calculation of the uterine artery resistance index as a percentage of the normal standard value at a given pregnancy duration revealed significant differences (P<0.001) between the two groups.ConclusionSerum progesterone and CA125 are useful provisional predictors of spontaneous abortion, whereas the Doppler indices are not. The two biomarkers could be used as a basis to counsel anxious couples.ClinicalTrials.govNCT02420769.
Case‐specific non‐linear finite element models to predict failure behavior in two functional spinal units
Authors: Groenen Karlijn H. J. , Bitter Thom , van Veluwen Tristia C. G. , van der Linden Yvette M. , Verdonschot Nico , Tanck Esther , Janssen Dennis 
Published: July 2018

ABSTRACTCurrent finite element (FE) models predicting failure behavior comprise single vertebrae, thereby neglecting the role of the posterior elements and intervertebral discs. Therefore, this study aimed to develop a more clinically relevant, case‐specific non‐linear FE model of two functional spinal units able to predict failure behavior in terms of (i) the vertebra predicted to fail; (ii) deformation of the specimens; (iii) stiffness; and (iv) load to failure. For this purpose, we also studied the effect of different bone density–mechanical properties relationships (material models) on the prediction of failure behavior. Twelve two functional spinal units (T6‐T8, T9‐T11, T12‐L2, and L3‐L5) with and without artificial metastases were destructively tested in axial compression. These experiments were simulated using CT‐based case‐specific non‐linear FE models. Bone mechanical properties were assigned using four commonly used material models. In 10 of the 11 specimens our FE model was able to correctly indicate which vertebrae failed during the experiments. However, predictions of the three‐dimensional deformations of the specimens were less promising. Whereas stiffness of the whole construct could be strongly predicted (R2 = 0.637–0.688, p < 0.01), we obtained weak correlations between FE predicted and experimentally determined load to failure, as defined by the total reaction force exhibiting a drop in force (R2 = 0.219–0.247, p > 0.05). Additionally, we found that the correlation between predicted and experimental fracture loads did not strongly depend on the material model implemented, but the stiffness predictions did. In conclusion, this work showed that, in its current state, our FE models may be used to identify the weakest vertebra, but that substantial improvements are required in order to quantify in vivo failure loads. © 2018 The Authors. Journal of Orthopaedic Research® Published by Wiley Periodical, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 36:3208–3218, 2018.