bluuebunny/crossref_metadata_2025_split huggingface dataset:
Automatisierte Glykan‐Assemblierung 19F‐markierter Glykansonden ermöglicht Hochdurchsatz‐NMR‐Untersuchungen von Protein‐Glykan‐Interaktionen
Authors: Fittolani Giulio , Shanina Elena , Guberman Mónica , Seeberger Peter H. , Rademacher Christoph , Delbianco Martina 
Published: March 2021

AbstractProtein‐Glykan‐Interaktionen vermitteln wichtige biologische Prozesse wie die Pathogen‐Wirt‐Invasion und zelluläre Kommunikation. Wir hier stellen einen schnellen Ansatz vor, der die automatisierte Glykan‐Assemblierung (AGA) von 19F‐markierten Sonden und Hochdurchsatz‐NMR‐Methoden integriert und die Untersuchung von Protein‐Glykan‐Interaktionen ermöglicht. Synthetische Lewis‐Typ‐2‐Antigene wurden gegen sieben glykanbindende Proteine (GBPs) durchmustert, darunter DC‐SIGN und BambL, die an HIV‐1‐ bzw. Lungeninfektionen bei immungeschwächten Patienten beteiligt sind, wobei die Präferenz für fucosylierte Glykane (Lex, H Typ 2, Ley) bestätigt wurde. Bisher unbekannte schwache Wechselwirkungen zwischen Glykanen und Lektinen wurden nachgewiesen und thermodynamische Daten gewonnen. Enzymatische Reaktionen wurden in Echtzeit überwacht und lieferten kinetische Parameter. Diese Ergebnisse zeigen den Nutzen von AGA in Kombination mit 19F‐NMR‐Spektroskopie für die Entdeckung und Charakterisierung von Glykan‐Protein‐Wechselwirkungen, wodurch sich neue Perspektiven für 19F‐markierte komplexe Glykane eröffnen.
25 Years of Reticular Chemistry
Authors: Freund Ralph , Canossa Stefano , Cohen Seth M. , Yan Wei , Deng Hexiang , Guillerm Vincent , Eddaoudi Mohamed , Madden David G. , Fairen‐Jimenez David , Lyu Hao , Macreadie Lauren K. , Ji Zhe , Zhang Yuanyuan , Wang Bo , Haase Frederik , Wöll Christof , Zaremba Orysia , Andreo Jacopo , Wuttke Stefan , Diercks Christian S. 
Published: March 2021

AbstractAt its core, reticular chemistry has translated the precision and expertise of organic and inorganic synthesis to the solid state. While initial excitement over metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) was undoubtedly fueled by their unprecedented porosity and surface areas, the most profound scientific innovation of the field has been the elaboration of design strategies for the synthesis of extended crystalline solids through strong directional bonds. In this contribution we highlight the different classes of reticular materials that have been developed, how these frameworks can be functionalized, and how complexity can be introduced into their backbones. Finally, we show how the structural control over these materials is being extended from the molecular scale to their crystal morphology and shape on the nanoscale, all the way to their shaping on the bulk scale.
Comparison of Two DNA Aptamers for Dopamine Using Homogeneous Binding Assays
Authors: Hou Yaoyao , Hou Jianjun , Liu Xixia 
Published: March 2021

AbstractDopamine is an essential neurotransmitter and its detection is important for bioanalytical chemistry. Two very different DNA aptamers have been reported for dopamine, one derived from an RNA aptamer (named Apt1) and other obtained via direct aptamer selection (named Apt2). In this study, we used four homogeneous binding assays to compare these two DNA dopamine aptamers. Thiazole orange (TO) fluorescence assay indicated that the Apt2 specifically bound with dopamine with a Kd of 2.37 μM, which was consistent with that from the isothermal titration calorimetry (ITC) assay. However, Apt1 had much less TO fluorescence change and also no signal from ITC. By labeling the two ends of the two aptamers by a fluorophore and a quencher, the aptamer beacons showed binding of dopamine only for Apt2. Finally, the label‐free AuNP‐based colorimetric assay showed no difference between these two aptamer sequences, and even non‐binding random DNA showed the same response, indicating that AuNPs were not a good probe for detecting dopamine. According to the data, Apt1 does not appear to be able to bind dopamine specifically, while Apt2 showed specific binding and could be used for developing related biosensors.
Enantioconvergent Substitution Reactions of Racemic Electrophiles by Organocatalysis
Authors: Kikuchi Jun , Terada Masahiro 
Published: March 2021

AbstractOver the past decades, the development of enantioselective catalysis using organocatalysts has evolved into an active research field and a number of enantioselective transformations have been established. However, despite their being a highly desirable process for the synthesis of organic molecules in an enantioenriched form, the enantioconvergent substitution reactions of racemic electrophiles using organocatalysts still present several challenges. Although intrinsic difficulties in the catalytic stereocontrol abound due to the initial chiral information of racemic electrophiles, in recent years, mechanistically diverse enantioconvergent processes have been intensively investigated in organocatalysis. This Minireview focuses on recent achievements in the development of enantioconvergent substitution reactions of racemic electrophiles using organocatalysts. The contents are classified on the basis of the mechanistic types of enantioconvergent processes.
Stochastic gradient descent‐based support vector machines training optimization on Big Data and HPC frameworks
Authors: Abeykoon Vibhatha , Fox Geoffrey , Kim Minje , Ekanayake Saliya , Kamburugamuve Supun , Govindarajan Kannan , Wickramasinghe Pulasthi , Perera Niranda , Widanage Chathura , Uyar Ahmet , Gunduz Gurhan , Akkas Selahatin 
Published: March 2021

SummarySupport vector machines (SVM) is a widely used machine learning algorithm. With the increasing amount of research data nowadays, understanding how to do efficient training is more important than ever. This article discusses the performance optimizations and benchmarks related to providing high‐performance support for SVM training. In this research, we have focused on a highly scalable gradient descent‐based approach to implementing the core SVM algorithm. In providing a scalable solution, we have designed optimized high‐performance computing and dataflow‐oriented SVM implementations. A high‐performance computing approach means the algorithm is implemented with the bulk synchronous parallel (BSP) model. In addition, we analyzed the language level optimizations and math kernel optimizations on a prominent HPC modeling programming language (C++) and dataflow modeling programming language (Java). In the experiments, we compared the performance of classic HPC models, classic dataflow models, and hybrid models designed on classic HPC and dataflow programming models. Our research illustrates a scientific approach in designing the SVM algorithm at scale in classic HPC, dataflow, and hybrid systems.
Recent Advances in Design Strategies for Tough and Stretchable Hydrogels
Authors: Maiti Chiranjit , Imani Kusuma Betha Cahaya , Yoon Jinhwan 
Published: March 2021

AbstractThe development of multifunctional hydrogels with excellent stretchability and toughness is one of the most fascinating subjects in soft matter research. Numerous research efforts have focused on the design of new hydrogel systems with superior mechanical properties because of their potential applications in diverse fields. In this Minireview, we consider the most up‐to‐date mechanically strong hydrogels and summarize their design strategies based on the formation of double networks and dual physical crosslinking. Based on the synthetic approaches and different toughening mechanisms, double‐network hydrogels can be further classified into three different categories, namely chemically crosslinked, hybrid physically–chemically crosslinked, and fully physically crosslinked. In addition to the above‐mentioned methods, we also discuss few uniquely designed hydrogels with the intention of guiding the future development of these fascinating materials for superior mechanical performance.
A systematic review of metacognitions in Internet Gaming Disorder and problematic Internet, smartphone and social networking sites use
Authors: Casale Silvia , Musicò Alessia , Spada Marcantonio M. 
Published: March 2021

AbstractBackgroundThe use of new technologies is growing, and some authors have suggested that frequent use might hide a non‐chemical addiction (i.e., technological addiction). Over the last 5 years, several studies investigating the role of metacognitions in technological addictions have been published. We aim to provide the first systematic review focused on this topic, by updating the initial evidence highlighted by a previous systematic review on metacognitions across addictive behaviours (Hamonniere & Varescon, 2018).MethodsElectronic literature databases (Pubmed, PsychINFO, SCOPUS and Web of Science) were searched to identify studies that examined the relationship between metacognitions and four different technological addictions (Internet Gaming Disorder, IGD; problematic Internet use, PIU; problematic smartphone use, PSU; and problematic social networking sites use, PSNSU).ResultsWe found 13 empirical studies published between 2018 and 2021. Positive low to moderate cross‐sectional associations between the four technological addictions and both generic and specific metacognitions were found, in accordance with the metacognitive model of addictive behaviours. Positive beliefs about worry, negative beliefs about thoughts concerning uncontrollability and danger, beliefs about the need to control thoughts and a lack of cognitive confidence were associated with IGD, PIU, PSU and PSNSU.ConclusionsThe absence of longitudinal studies prevents us from providing definitive answers about the role of metacognitions in technological addictions. Despite this limitation, interventions that target metacognitions could be beneficial for people presenting with technological addictions.
An intermodulation distortion estimation method for linear CMOS circuits
Authors: Baxevanakis Dimitrios , Alimisis Vassilis , Sotiriadis Paul P. 
Published: March 2021

SummaryThis article presents a general, time‐domain method for intermodulation distortion estimation that offers a fast, systematic, and compact formulation. It can be applied to any linear CMOS circuit architecture, with any number of stages, ranging from amplifiers and transconductors to filters, that are characterized by weakly nonlinear behavior. Each CMOS stage of the circuit is modeled as aGm‐stage with an output current expressed as a more involved function of its input and output voltages, taking into account both powers and cross‐product terms necessary to accurately capture the nonlinear behavior. The proposed method is easily implemented in numerical computing environments like MATLAB or Python and results in a very fast distortion estimation. A number of example topologies simulated in Cadence Spectre illustrate the application of the method and demonstrate its accuracy.
Microcomputed tomography used to link head morphology and observed feeding behavior in cichlids of Lake Malaŵi
Authors: Konings Adrianus F. , Wisor Joshua M. , Stauffer Jay R. 
Published: March 2021

AbstractCichlids inhabiting the Great Lakes of Africa have radiated extremely rapidly, with Lake Malaŵi harboring some 850 species. This rapid radiation may be linked to the diversity in behaviors, sexual selection, and phenotypic plasticity. To determine the relationships between morphology and behaviors, microcomputed tomography (microCT) was used to observe internal morphological structures. Observed morphological adaptations were linked with observed behavior of cichlids in Lake Malaŵi with respect to the various available food resources. Many of these adaptations have parallels, sometimes into the finest details, in other drainage systems and can thus be considered as variations of how cichlids in general respond to environmental opportunities and challenges. Variations in the structure and teeth of the pharyngeal jaws and the oral jaws allowed for fine tuning of specializations, so that various species can utilize the same source without direct competition. We suggested that high‐resolution X‐ray computed tomography will permit scientists to infer life history and behavior characters of rare or extinct taxa from a detailed examination of morphology and linkages between morphology and behavior found in extant species.
Tackling unresolved questions in forest ecology: The past and future role of simulation models
Authors: Maréchaux Isabelle , Langerwisch Fanny , Huth Andreas , Bugmann Harald , Morin Xavier , Reyer Christopher P.O. , Seidl Rupert , Collalti Alessio , Dantas de Paula Mateus , Fischer Rico , Gutsch Martin , Lexer Manfred J. , Lischke Heike , Rammig Anja , Rödig Edna , Sakschewski Boris , Taubert Franziska , Thonicke Kirsten , Vacchiano Giorgio , Bohn Friedrich J. 
Published: March 2021

AbstractUnderstanding the processes that shape forest functioning, structure, and diversity remains challenging, although data on forest systems are being collected at a rapid pace and across scales. Forest models have a long history in bridging data with ecological knowledge and can simulate forest dynamics over spatio‐temporal scales unreachable by most empirical investigations.We describe the development that different forest modelling communities have followed to underpin the leverage that simulation models offer for advancing our understanding of forest ecosystems.Using three widely applied but contrasting approaches – species distribution models, individual‐based forest models, and dynamic global vegetation models – as examples, we show how scientific and technical advances have led models to transgress their initial objectives and limitations. We provide an overview of recent model applications on current important ecological topics and pinpoint ten key questions that could, and should, be tackled with forest models in the next decade.Synthesis. This overview shows that forest models, due to their complementarity and mutual enrichment, represent an invaluable toolkit to address a wide range of fundamental and applied ecological questions, hence fostering a deeper understanding of forest dynamics in the context of global change.
Genomic divergence in sympatry indicates strong reproductive barriers and cryptic species within Eucalyptus salubris
Authors: Binks Rachel M. , Steane Dorothy A. , Byrne Margaret 
Published: March 2021

AbstractGenetic studies are increasingly detecting cryptic taxa that likely represent a significant component of global biodiversity. However, cryptic taxa are often criticized because they are typically detected serendipitously and may not receive the follow‐up study required to verify their geographic or evolutionary limits. Here, we follow‐up a study of Eucalyptus salubris that unexpectedly detected two divergent lineages but was not sampled sufficiently to make clear interpretations. We undertook comprehensive sampling for an independent genomic analysis (3,605 SNPs) to investigate whether the two purported lineages remain discrete genetic entities or if they intergrade throughout the species’ range. We also assessed morphological and ecological traits, and sequenced chloroplast DNA. SNP results showed strong genome‐wide divergence (FST = 0.252) between two discrete lineages: one dominated the north and one the southern regions of the species’ range. Within lineages, gene flow was high, with low differentiation (mean FST = 0.056) spanning hundreds of kilometers. In the central region, the lineages were interspersed but maintained their genomic distinctiveness: an indirect demonstration of reproductive isolation. Populations of the southern lineage exhibited significantly lower specific leaf area and occurred on soils with lower phosphorus relative to the northern lineage. Finally, two major chloroplast haplotypes were associated with each lineage but were shared between lineages in the central distribution. Together, these results suggest that these lineages have non‐contemporary origins and that ecotypic adaptive processes strengthened their divergence more recently. We conclude that these lineages warrant taxonomic recognition as separate species and provide fascinating insight into eucalypt speciation.
Changes in the Montagu’s Harrier Circus pygargus diet in Eastern Poland across decades promote insects and reptilians, but not birds and rodents
Authors: Kitowski Ignacy , Jakubas Dariusz , Mirski Paweł , Pitucha Grzegorz , Markowska Kornelia 
Published: March 2021

AbstractWe investigated temporal changes in diet composition of the Montagu's HarrierCircus pygargusbreeding in natural habitat (calcareous peat bog) in SE Poland. We characterized diet composition in a three‐year period (2007–2009), based on pellet analyses. We investigated whether diet composition was affected by years or stage of breeding. We compared diet of the studied population between 2000s and 1990s and with other populations. We found that the food of the studied population was dominated by insects and mammals (by number) and mammals and birds (by biomass). Biomass and abundance of main prey items differed between studied years because of different air temperatures. We found some interannual differences in contribution of some prey items including higher number of thermophilic prey (insects and amphibians) in warmer years. Comparison of pellet composition in the 1990s and 2000s revealed significant increase in the abundance of thermophilic prey (insects and reptiles) and decrease of mammals includingMicrotusvoles and birds. Those changes may be linked to habitat changes in areas neighboring peat bogs and climate change‐induced changes in prey communities. The studied population was able to respond to changes in foraging habitats and prey composition by opportunistic foraging on easily available prey. The diet of the studied population is the most similar to the geographically closest populations foraging in similar habitats and characterized by high contribution of insects.
Past connections with the mainland structure patterns of insular species richness in a continental‐shelf archipelago (Aegean Sea, Greece)
Authors: Hammoud Cyril , Kougioumoutzis Konstantinos , Rijsdijk Kenneth F. , Simaiakis Stylianos M. , Norder Sietze J. , Foufopoulos Johannes , Georgopoulou Elisavet , Van Loon Emiel E. 
Published: March 2021

AbstractRecent research in island biogeography has highlighted the important role of late Quaternary sea‐level fluctuations in shaping biogeographic patterns in insular systems but focused on oceanic systems. Through this study, we aim investigate how late Quaternary sea‐level fluctuations shaped species richness patterns in continental‐shelf island systems. Focusing on the Aegean archipelago, we first compiled maps of the area's geography using published data, under three sea‐level stands: (a) current; (b) median sea‐level over the last nine glacial–interglacial cycles (MSL); and (c) Last Glacial Maximum (LGM). We gathered taxon–island occurrences for multiple chorotypes of angiosperms, butterflies, centipedes, and reptiles. We investigated the impact of present‐day and past geographic settings on chorological groups by analyzing island species–area relationships (ISARs) and using generalized linear mixed models (GLMMs) selection based on multiple metrics of goodness of fit. Our results confirm that the Aegean's geography has changed dramatically since the LGM, whereas the MSL only modestly differs from the present configuration. Apart for centipedes, paleogeographic changes affected both native and endemic species diversity through altering connections between land‐bridge islands and the mainland. On land‐bridge islands, we detected over‐representation of native species and under‐representation of endemics. Unlike oceanic islands, sea‐level‐driven increase of isolation and area contraction did not strongly shape patterns of species richness. Furthermore, the LGM configurations rather than the MSL configuration shaped patterns of endemic species richness. This suggests that even short episodes of increased connectivity with continental populations are sufficient to counteract the genetic differentiation of insular populations. On the other hand, the over‐representation of native nonendemic species on land‐bridge islands reflected MSL rather than LGM mainland connections. Our study shows that in terms of processes affecting species richness patterns, continental archipelagos differ fundamentally from oceanic systems because episodic connections with the mainland have profound effects on the biota of land‐bridge islands.
Prey and predator density‐dependent interactions under different water volumes
Authors: Cuthbert Ross N. , Dalu Tatenda , Wasserman Ryan J. , Sentis Arnaud , Weyl Olaf L. F. , Froneman P. William , Callaghan Amanda , Dick Jaimie T. A. 
Published: March 2021

AbstractPredation is a critical ecological process that directly and indirectly mediates population stabilities, as well as ecosystem structure and function. The strength of interactions between predators and prey may be mediated by multiple density dependences concerning numbers of predators and prey. In temporary wetland ecosystems in particular, fluctuating water volumes may alter predation rates through differing search space and prey encounter rates. Using a functional response approach, we examined the influence of predator and prey densities on interaction strengths of the temporary pond specialist copepodLovenula rayneraepreying on cladoceran prey,Daphnia pulex, under contrasting water volumes. Further, using a population dynamic modeling approach, we quantified multiple predator effects across differences in prey density and water volume. Predators exhibited type II functional responses under both water volumes, with significant antagonistic multiple predator effects (i.e., antagonisms) exhibited overall. The strengths of antagonistic interactions were, however, enhanced under reduced water volumes and at intermediate prey densities. These findings indicate important biotic and abiotic contexts that mediate predator–prey dynamics, whereby multiple predator effects are contingent on both prey density and search area characteristics. In particular, reduced search areas (i.e., water volumes) under intermediate prey densities could enhance antagonisms by heightening predator–predator interference effects.