bluuebunny/crossref_metadata_2025_split huggingface dataset:
Life Cycle Assessment for the Organocatalytic Synthesis of Glycerol Carbonate Methacrylate
Authors: Büttner Hendrik , Kohrt Christina , Wulf Christoph , Schäffner Benjamin , Groenke Karsten , Hu Yuya , Kruse Daniela , Werner Thomas 
Published: April 2019

AbstractBifunctional ammonium and phosphonium salts have been identified as potential organocatalysts for the synthesis of glycerol carbonate methacrylate (GCMA). Three of these catalysts showed high efficiency and allowed the conversion of glycidyl methacrylate with CO2 to the desired product in >99 % conversion and selectivity. Subsequently, immobilized analogues of selected catalysts were prepared and tested. A phenol‐substituted phosphonium salt on a silica support proved to be a promising candidate in recycling experiments. The same catalyst was used in 12 consecutive runs, resulting in GCMA yields of up to 88 %. Furthermore, a life cycle assessment was conducted for the synthesis of GCMA starting from epichlorohydrin (EPH) and methacrylic acid (MAA). For the functional unit of 1 kg GCMA, 15 wt % was attributed to the incorporation of CO2, which led to a reduction of the global warming potential of 3 % for the overall process.
Differential localization of histone variant TH2B during the first round compared with subsequent rounds of spermatogenesis
Authors: Beedle My‐Thanh , Topping Traci , Hogarth Cathryn , Griswold Michael 
Published: April 2019

AbstractBackgroundMale germ cells are unique because they express a substantial number of variants of the general DNA binding proteins, known as histones, yet the biological significance of these variants is still unknown. In the present study, we aimed to address the expression pattern of the testis‐specific histone H2B variant (TH2B) and the testis‐specific histone H2A variant (TH2A) within the neonatal mouse testis.ResultsWe demonstrate that TH2B and TH2A are present in a testis‐enriched for undifferentiated spermatogonia. Co‐localization studies with an undifferentiated marker, ZBTB16, revealed that TH2B and ZBTB16 co‐localize in the neonatal testis. Upon the appearance of the primary spermatocytes, TH2B no longer co‐localized with the ZBTB16 positive spermatogonia but were instead detected within the differentiating spermatogonia. This pattern of expression where TH2B and ZBTB16 no longer co‐localize was maintained in the adult testis.ConclusionThese findings are in contrast to previous studies, which demonstrated that TH2B and TH2A were found only in adult spermatocytes. Our data are in support of a switch in the expression of these variants following the first round of spermatogonial differentiation. These studies reinforce current understandings that spermatogonia within the neonatal mouse testis are inherently different from those residing within the adult testis.
An evaluation of isotopic (δ2H) methods to provide estimates of avian breeding and natal dispersal
Authors: López‐Calderón C. , Van Wilgenburg Steven L. , Roth Amber M. , Flaspohler David J. , Hobson Keith A. 
Published: April 2019

AbstractNatal and breeding dispersal represents an important component of animal demography and metapopulation theory. This phenomenon also has implications for conservation and management because understanding movements of individuals potentially allows the identification of key habitats that may be acting as population sources or sinks. Intrinsic markers such as stable isotope abundance in tissues that can be associated with provenance can provide a coarse but pragmatic solution to understanding such movements. Different methodologies have been proposed to quantify natal and breeding dispersal by using stable isotope analyses of keratinous tissues (hair, feathers), each of them with their own advantages and limitations. Here, we compared results provided by four different methods to estimate dispersal (three already published and one novel) in animals using stable isotope measurements. We used a single large dataset of feather δ2H values from golden‐winged warblers (Vermivora chrysoptera) representing five different populations breeding in North America to compare model results. We propose one method as the most adequately supported by data, and we used this method to demonstrate how biological factors explaining dispersal status can be identified and geographical origins of immigrants inferred. Our results point to a generalized methodological approach to using stable isotope data to study immigration and dispersal in birds and other animals.
Disentangling effects of invasive species and habitat while accounting for observer error in a long‐term amphibian study
Authors: Rowe Jennifer C. , Duarte Adam , Pearl Christopher A. , McCreary Brome , Galvan Stephanie K. , Peterson James T. , Adams Michael J. 
Published: April 2019

AbstractThe invasive American bullfrog (Lithobates catesbeianus) and a variety of non‐native sport fish commonly co‐occur in lowland lentic habitats of the western United States. Both invasive taxa are implicated in declines of native amphibians in this region, but few long‐term studies of communities exist. Further, field studies of invasive–native interactions are complicated by confounding habitat modifications and observation errors. We surveyed amphibians and measured habitat characteristics for 12 yr across 38 wetland sites within the Willamette Valley, Oregon, USA. We assessed the influence of invasive species, habitat, and their interactions on the distributions of five native amphibian species using a multispecies dynamic occupancy model that accounted for false‐negative and false‐positive detections. In general, habitat characteristics—such as within‐pond vegetation cover, surrounding forest, and drought severity—were important for local persistence of native species when bullfrogs co‐occurred. We also found evidence of a cumulative negative effect of bullfrogs and non‐native fish (families Centrarchidae and Ictaluridae) on northern red‐legged frog (Rana aurora) local persistence that was mediated by the dominance of invasive reed canarygrass (Phalaris arundinacea). Non‐native fish and bullfrogs had variable effects on native amphibian species, but neither invasive taxon appears to be causing declines in occupied sites within our study area. Moreover, species relationships with habitat differed when invaders were present, indicating that certain habitats may increase persistence of native amphibians in the invaded landscape.
Increasing drought favors nonnative fishes in a dryland river: evidence from a multispecies demographic model
Authors: Rogosch Jane S. , Tonkin Jonathan D. , Lytle David A. , Merritt David M. , Reynolds Lindsay V. , Olden Julian D. 
Published: April 2019

AbstractUnderstanding how novel biological assemblages are structured in relation to dynamic environmental regimes remains a central challenge in ecology. Demographic approaches to modeling species assemblages show promise because they seek to represent fundamental relationships between population dynamics and environmental conditions. In dryland rivers, rapidly changing climate conditions have shifted drought and flooding regimes with implications for fish communities. Our goals were to (1) develop a mechanistic multispecies demographic model that links native and nonnative species with river flow regimes, and (2) evaluate demographic responses in population and community structure to changing flow regimes. Each fish species was represented by a stage‐structured matrix, and species were coupled together into a multispecies framework through density‐dependent relationships in reproduction. Then, community dynamics were simulated through time using annual flow events classified from gaged streamflow data. We parameterized the model with vital rates and flow–response relationships for a community of native and nonnative fishes using literature‐derived values. We applied the simulation model to the Verde River (Arizona, USA), a major tributary within the Colorado River Basin, for the past half century (1964–2017). Model validation revealed a match between model projections and relative abundance trends observed in a long‐term fish monitoring dataset (1994–2008). At the beginning of the validation period (1994), model and survey observations showed that native species comprised approximately 80% of total abundance. Model projections beyond the survey data (2008–2017) predicted a shift from a native dominant to a nonnative dominant assemblage, coinciding with increasing drought frequency. Trade‐offs between native and nonnative species dominance emerged from differences in mortality in response to the changing sequence of major flow events including spring floods, summer high flows, and droughts. In conclusion, the demographic approach presented here provides a flexible modeling framework that is readily applied to other stream systems and species by adjusting or transferring, when appropriate, species vital rates and flow‐event thresholds.
Creating a window of opportunity for establishing ecosystem engineers by adding substratum: a case study on mussels
Authors: Capelle Jacob J. , Leuchter Lennet , de Wit Maurice , Hartog Eva , Bouma Tjeerd J. 
Published: April 2019

AbstractEcosystem engineers typically exert positive feedback on their environment, which enhances their performance. Such positive feedback is lacking in the establishment phase, when densities are too low and/or patches are too small. There is a strong need to unravel the mechanisms for overcoming the resulting establishment thresholds, both for ecological restoration purposes and to be able to use their services. In the present study, we question whether providing a transient substratum can be used as tool to overcome establishment thresholds, by creating a window of opportunity for initial settlement, using mussels (Mytilus edulis) as a model system. Combining field and flume experiments, we study how biogenic substratum enrichment in the form of a shell layer on a soft mudflat affects the critical dislodgement thresholds and, thus, the chances of mussel establishment at different mussel densities and aggregation states. Flume results showed that the presence of a shell layer reduced dislodgement of mussel patches in low‐energy environments but was conditional for establishment in high‐energy environments. That is, in high‐energy environments with shells, aggregation into clumps enhanced dislodgement, while dislodgement was reduced with increasing overall mussel biomass and overall mussel patch weight. Without shells, dislodgement was always 100%. These findings agreed with our field studies, which showed that coarse shell material reduced mussel losses (by a factor of 3), reduced aggregation (by a factor of 2.4), and increased attachment strength (by a factor of 2.4). Overall, our results show that the local presence of biogenic substratum increases the chance of mussel establishment by enhancing the critical hydrodynamic dislodgement threshold. Thus, the local addition of a biogenic substratum may create a window of opportunity to initiate settlement in more dynamic environments, to shift at a local scale from a bare mudflat state into an established biogenic reef state. Our findings have clear implications for how to approach restoration and management of ecosystem engineers dominated systems. For instance, when positive feedback of ecosystem engineers is lacking, (1) the transient offering of suitable settling substratum may be a necessary step to overcome establishment thresholds, and (2) this becomes increasingly important with increasing abiotic stress.
Computational fluid dynamics analysis of heat transfer in a greenhouse solar dryer “chapel‐type” coupled to an air solar heating system
Authors: Román‐Roldán Nicolás‐Iván , López‐Ortiz Anabel , Ituna‐Yudonago Jean‐Fulbert , García‐Valladares Octavio , Pilatowsky‐Figueroa Isaac 
Published: April 2019

AbstractThe distribution of turbulent kinetic energy (TKE), temperature, and velocity of humid air inside the greenhouse solar dryer (GHSD) was numerically investigated using 3D CFD ANSYS FLUENT code. The effect of solar radiation was coupled with the energy equations using the discrete ordinate model. Numerical simulations were based on two geometric models: Real model and model with reduced height, the solution was in good agreement with experimental data of temperature. The results of the real model showed that the TKE is ranged between 1.27 m2/s2 and 6 m2/s2 with an average of about 1.6 m2/s2 for the entire greenhouse dryer (GHD) volume. The greatest TKE magnitude is in the paths of the diffusers, which caused a temperature drop of about 2 K in the areas near the walls. Consequently, almost homogeneous temperature distribution was obtained in the entire volume of the GHD, although the average temperature was 315 K, and a gradient with respect to ambient temperature was of 14 K, that is, suitable for drying. Also, the average air velocity at 1 m height was 0.71 m/s, which is a value near the lowest limit (0.6 m/s) of forced convection drying. The improvement in the GHD by 36.5% volume reduction allowed an increase in the average TKE of 3.8 m2/s2 (2.4 times more than the previous one) located in the middle of the greenhouse; the average temperature reached 316.5 K with a gradient of 15.5 K, which represents an increase of 1.5 K (11%) compared to the real geometric model. The air velocity at 1 m height increased to 0.9 m/s in the improved geometric model (a growth of 35.7% compared with the previous geometry). More than 95% of the improved GHD volume has a uniform temperature, which is very suitable for a good quality drying process with higher speed.
Topographic change and numerically modelled near surface wind flow in a bowl blowout
Authors: Smyth Thomas A.G. , Hesp Patrick A. , Walker Ian J. , Wasklewicz Thad , Gares Paul A. , Smith Alexander B. 
Published: April 2019

AbstractA number of studies have measured and numerically modelled near surface wind velocity over a range of aeolian landforms and made suppositions about topographic change and landform evolution. However, the precise measurement and correlation of flow dynamics and resulting topographic change have not yet been fully realized. Here, using repeated high‐resolution terrestrial laser scanning and numerical flow modelling within a bowl blowout, we statistically analyse the relationship between wind speed, vertical wind velocity, turbulent kinetic energy and topographic change over a 33‐day period.Topographic results showed that erosion and deposition occurred in distinct regions within the blowout. Deposition occurred in the upwind third of the deflation basin, where wind flow became separated and velocity and turbulent kinetic energy decreased, and erosion occurred in the downwind third of the deflation basin, where wind flow reattached and aligned with incident wind direction.Statistical analysis of wind flow and topographic change indicated that wind speed had a strong correlation with overall topographic change and that vertical wind velocity (including both positive and negative) displayed a strong correlation with negative topographic change (erosion). Only weak or very weak correlations exist for wind flow parameters and positive topographic change (accretion). This study demonstrates that wind flow modelling using average incident wind conditions can be utilized successfully to identify regions of overall change and erosion for a complex aeolian landform, but not to identify and predict regions where solely accretion will occur. © 2019 John Wiley & Sons, Ltd.
The effects of angular orientation and ultraviolet aging on ETFE wire flame spread
Authors: Zhang Yue , Fang Jun , Wang Jingwu , Zhao Luyao , Zhang Yongming 
Published: April 2019

SummaryThis paper considers the solid phase heat conduction along with the effect of ultraviolet (UV) aging on the flame spread and separately discussed the upward and downward flame spread. The 0.15‐mm‐thick ethylene‐tetrafluoro‐ethylene (ETFE) insulated with a 0.5‐mm‐diameter copper core used in the paper. The flame spread was measured at various inclined angles (vertical ± 90○, to horizontal 0○) in the directions of gravity assistance (up) and gravity opposition (down). The ETFE was categorized into two groups: the unaged ETFE (ETFE‐U) and the UV aged ETFE (ETFE‐A). The kinetic parameters of samples were obtained from thermogravimetric analysis (TGA) test. The flame spread experimental results showed that the bigger the absolute inclined angle, the higher the flame spread rate. Besides, the effect of UV aging on the upward spread is greater than that of the downward spread. A theoretical system was established through the flame spread experiments and TGA test. The heat flux and the flame spread rate of upward and downward equations were presented to reveal the effects of solid conduction, orientation, inclination, and UV aging on wire flame spread.
Identification of acrolein metabolites in human buccal cells, blood, and urine after consumption of commercial fried food
Authors: Wang Tse‐Wen , Liu Jin‐Hui , Tsou Han‐Hsing , Liu Tsung‐Yun , Wang Hsiang‐Tsui 
Published: April 2019

AbstractScopeAcrolein is a highly electrophilic α,β‐unsaturated aldehyde and is associated with human diseases. It is formed by Maillard reaction during food processing and could be detected in the emissions of overheated cooking oils. Consequently, humans are at risk of acrolein exposure through consumption of such prepared food.Methods and resultsWe conducted three human studies that healthy subjects (21–30 years) were served fried foods including fried chicken and French fries from three commercial fast food restaurants. Acrolein‐related metabolites including urinary 3‐hydroxypropyl mercapturic acid (3‐HPMA), serum acrolein‐protein conjugates (Acr‐FDP), and buccal acrolein‐induced DNA damages (Acr‐dG adducts) along with GSH levels in serum or buccal cells were investigated for different times after consumption.ConclusionUrinary 3‐HPMA levels were increased after 2‐hr consumption of fried food with an elimination half‐life of 10 hr. In addition, increased Acr‐dG adducts in oral cavity were inversely correlated to buccal glutathione (GSH) levels after consumption. However, there was no significant change in systemic GSH levels or Acr‐FDP adducts in serum. These results indicate that exposure of acrolein from consuming fried food affects local oral cavity homeostasis. This may provide a possible link between intake of fried food and increased risk of upper aerodigestive tract cancers.
S100 and CD34 positive spindle cell tumor with prominent perivascular hyalinization and a novel NCOA4‐RET fusion
Authors: Michal Michael , Ptáková Nikola , Martínek Petr , Gatalica Zoran , Kazakov Dmitry V. , Michalová Květoslava , Stoláriková Lýdia , Švajdler Marián , Michal Michal 
Published: April 2019

AbstractWe report a case of a 35‐year old male patient with a tumor located in the deep dermis on his forearm. The lesion was completely excised but recurred 4 years later. The patient showed no signs of neurofibromatosis type 1. The morphology and immunophenotype of the tumor corresponded to the recently characterized group of soft tissue spindle cell lesions defined by a relatively uniform cytomorphology, patternless architecture, conspicuous stromal and perivascular hyalinization, S100 and CD34 coexpression and recurrent fusions involving RAF1, BRAF, and NTRK1/2 genes. Using a 592‐gene panel and massively parallel next‐generation sequencing platform, we initially detected only NF1 gene mutation in our case. However, further molecular testing with Archer fusion assay revealed a novel NCOA4‐RET gene fusion, adding it to the list of multiple kinase fusions originally reported in these tumors. Although break‐apart FISH showed false negative result due to the presence of intrachromosomal rearrangement, RT‐PCR confirmed the fusion transcript. Knowing the exact fusion is of great clinical importance especially for patients within the aggressive subset of these neoplasms that could be treated with selective kinase inhibitors. The presented case underscores the benefits of massively parallel sequencing as the types and number of gene fusions these tumors can potentially harbor render single‐gene assays such as FISH impractical, and in this particular case, also insensitive.
Unsupervised organization of cervical cells using bright‐field and single‐shot digital holographic microscopy
Authors: Mangal Jyoti , Monga Rashi , Mathur Sandeep R. , Dinda Amit K. , Joseph Joby , Ahlawat Sarita , Khare Kedar 
Published: April 2019

AbstractWe report results on unsupervised organization of cervical cells using microscopy of Pap‐smear samples in brightfield (3‐channel color) as well as high‐resolution quantitative phase imaging modalities. A number of morphological parameters are measured for each of the 1450 cell nuclei (from 10 woman subjects) imaged in this study. The principal component analysis (PCA) methodology applied to this data shows that the cell image clustering performance improves significantly when brightfield as well as phase information is utilized for PCA as compared to when brightfield‐only information is used. The results point to the feasibility of an image‐based tool that will be able to mark suspicious cells for further examination by the pathologist. More importantly, our results suggest that the information in quantitative phase images of cells that is typically not used in clinical practice is valuable for automated cell classification applications in general.
Rational approaches for toxicological assessments of nanobiomaterials
Authors: Pandey Shalabh , Mishra Awanish 
Published: April 2019

AbstractThe nanobiomaterials display unique and distinguished usefulness in day‐to‐day life. The application of nanobiomaterials is being utilized in several segments, including semiconductor industries, cosmetics, and medicines. Alongside their usefulness these nanobiomaterials have potential toxicity which may limit it's further use. As there is sparse information on toxicological facets of nanomaterials available, a proactive approach for evaluation of potential risk of nanobiomaterials should be exercised. This review explains the potential mechanism of nanobiomaterials toxicity and rational approaches for selection of protocols to study toxicity of nanobiomaterials.