bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unlocking the 5‐exo Pathway with the AuI‐Catalyzed Alkoxycyclization of 1,3‐Dien‐5‐ynes
Authors: Virumbrales Cintia , Suárez‐Pantiga Samuel , Marín‐Luna Marta , Silva López Carlos , Sanz Roberto 
Published: May 2020

AbstractThe first general regio‐ and stereoselective 5‐exo gold(I)‐catalyzed alkoxycyclization of a specific class of 1,5‐enynes such as 1,3‐dien‐5‐ynes has been described, despite 1,5‐enynes being known to almost invariably proceed via endo cyclizations under gold‐catalysis. The configuration of the terminal alkene in the starting 1,3‐dien‐5‐yne plays a crucial role on the regiochemical outcome of the reaction. A wide variety of interesting alkoxy‐functionalized alkylidenecyclopentenes have been synthesized from 1‐monosubstituted (E)‐1,3‐dien‐5‐ynes. On the contrary, the corresponding Z isomers evolve affording formal 6‐endo cyclization products. In addition, mechanistic exploration supports a highly stabilized carbocation as a key intermediate instead of a highly constrained cyclopropyl gold carbene from E isomers, and also accounts for the well differentiated reactivity observed between both E/Z geometrical isomers as well as for the stereochemical outcome of the reaction.
Impact of Chirality on Hydrogen‐Bonded Supramolecular Assemblies and Photoconductivity of Diketopyrrolopyrrole Derivatives
Authors: Militzer Swann , Nishimura Nozomi , Ávila‐Rovelo Nelson Ricardo , Matsuda Wakana , Schwaller Duncan , Mésini Philippe J. , Seki Shu , Ruiz‐Carretero Amparo 
Published: May 2020

AbstractHydrogen bonds can efficiently guide the self‐assembly of organic materials, enabling to tune the properties of the aggregation processes. In the case of π‐conjugated materials, several parameters such as temperature, concentration and solvent can be used to modify the aggregation state while tuning the optoelectronic properties. Chirality can be included within the impacting parameters due to the differences in molecular packing. Here, chiral and achiral thiophene‐capped diketopyrrolopyrrole derivatives were designed and synthesized containing amide bonds, with the aim to study the interplay between chiral assemblies and their stabilization through hydrogen‐bonding. Differences in aggregation properties were observed with spectroscopy and microscopy, and a contactless microwave‐based technique was used to study their intrinsic charge carrier mobility. The positive role of hydrogen‐bonding has been highlighted and the differences between chiral and achiral compounds have been elucidated.
Spiropyran Meets Guanine Quadruplexes: Isomerization Mechanism and DNA Binding Modes of Quinolizidine‐Substituted Spiropyran Probes
Authors: Avagliano Davide , Sánchez‐Murcia Pedro A. , González Leticia 
Published: May 2020

AbstractThe recent delivery of a fluorescent quinolizidine‐substituted spiropyran, which is able to switch in vivo and bind to guanine quadruplexes (G4) at physiological pH values, urged us to elucidate its molecular switching and binding mechanism. Combining multiscale dynamical studies and accurate quantum chemical calculations, we show that, both in water and in the G4 environment, the switching of the spiropyran ring is not promoted by an initial protonation event—as expected by the effect of low pH solutions—but that the deprotonated merocyanine form is an intermediate of the reaction leading to the protonated open species. Additionally, we investigate the binding of both deprotonated and protonated open forms of merocyanine to c‐MYC G4s. Both species bind to G4s albeit with different hydrogen‐bond patterns and provide distinct rotamers around the exocyclic double bond of the merocyanine forms. Altogether, our study sheds light on the pharmacophoric points for the binding of these probes to DNA, and thereby, contributes to future developments of new G4 binders of the remarkable family of quinolizidine‐substituted spiropyrans.
SaaS software performance issue diagnosis using independent component analysis and restricted Boltzmann machine
Authors: Wang Rui , Ying Shi 
Published: May 2020

SummarySaaS software performance issue diagnosis aims to classify the type of the performance records. Deep classification method has gained much attention as a way to construct hierarchical representations from a small amount of labeled data. However, there are few researches on how to solve the classification problem of performance issues by using the deep classification method. In addition, shallow classification methods exist some problems, such as the training sample is large and the ability to fit complex functions is weak. In this article, we proposed a deep performance issue classification method based on Independent Component Analysis (ICA) and Restricted Boltzmann Machine (RBM). ICA is used to extract the features, after this process, the classification feature is obtained as RBM input, and the extracted information about performance issue is transformed into identifiable information for the classifier via visible structure of input; Hidden layer for RBM is built to realize the data transmission between hidden structure, keeping the key information; And the classification algorithm is implemented to solve our performance issue diagnosis problem of SaaS software. Experiments show that the performance of our approach is superior to the classical shallow classification algorithm, and it also meet the efficiency requirement.
A virtualized data center energy‐saving mechanism based on switching operating mode of physical servers and reserving virtual machines
Authors: Yin Chunxia , Liu Jian , Jin Shunfu 
Published: May 2020

AbstractThe energy consumption of virtualized data centers has grown very fast in last several years. Because a large number of hosts are running in an idle state, virtualized data centers waste a large amount of electric energy. To save more energy for virtualized data centers, an energy‐saving mechanism is proposed based on switching operating mode of physical servers and reserving virtual machines (VMs). The main idea is that when the amount of idle VMs reaches twice of a specified threshold, half of these idle VMs are reserved to process the new task that is about to arrive, and the physical server which hosts the other half of the idle VMs is switched to the sleep mode. From the perspective of task arrival rate and sleep parameters, we use two‐dimensional Markov processes to analyze the proposed energy‐saving mechanisms. By using matrix geometry solutions, we theoretically estimate energy consumption and response performance. According to the numerical experiments, the proposed energy‐saving mechanism obviously cut down electric energy consumption and ensures response performance. Finally, the specified threshold for the amount of VMs is optimized by building a cost function.
A self‐stabilizing algorithm for constructing a maximal (σ,τ)‐directed acyclic mixed graph
Authors: Kim Yonghwan , Katayama Yoshiaki , Masuzawa Toshimitsu 
Published: May 2020

SummaryA (σ,τ)‐directed acyclic mixed graph (DAMG) is a mixed graph, which allows both arcs (or directed edges) and (undirected) edges such that there exist exactly σ source nodes and τ sink nodes, but there exists no directed cycle (consisting of only arcs). Each source (resp. sink) node has at least one outgoing (resp. incoming) arc, but no incoming (resp. outgoing) arc. Moreover any other node is neither a source nor a sink node; it has no incident arc or both outgoing and incoming arcs. This article considers maximal (σ,τ)‐DAMG constructions: when an arbitrary undirected connected graph G=(V,E) and two distinct subsets S and T of node set V, where |S|=σ and |T|=τ, are given, construct a maximal (σ,τ)‐DAMG with source node set S and sink node set T by assigning directions to as many edges as possible (ie, by changing edges into arcs). The maximality implies that changing any more edges to arcs violates the conditions of a (σ,τ)‐DAMG (eg, a sink node has an outgoing arc or a directed cycle is created). As a previous work, a self‐stabilizing algorithm for constructing a maximal (1,1)‐DAMG in an arbitrary undirected connected graph is proposed for the case of σ=τ=1. In this article, we consider construction of a maximal (σ,τ)‐DAMG for any σ and τ. First, we introduce a self‐stabilizing algorithm for a maximal (1,2)‐DAMG construction in any connected graph (with few constraints), which is based on the previous work. Concerning generalization of σ and τ to arbitrary values, we first clarify the necessary and sufficient condition under which a (σ,τ)‐DAMG can be constructed in which a source and a sink node sets are given. Then, we propose a generalized self‐stabilizing algorithm that constructs a (σ,τ)‐DAMG when a given graph with a source and a sink node sets satisfies the above condition.
Genetic studies of extra‐early provitamin‐A maize inbred lines and their hybrids in multiple environments
Authors: Badu‐Apraku B. , Fakorede M.A.B. , Talabi A.O. , Oyekunle M. , Aderounmu M. , Lum A.F. , Ribeiro P.F. , Adu G.B. , Toyinbo J.O. 
Published: May 2020

AbstractVitamin A deficiency, drought, low soil nitrogen (low‐N), andStriga hermonthicaparasitism of maize (Zea maysL.) cause malnutrition and food insecurity in sub‐Saharan Africa. The objectives of this study were to determine combining abilities of extra‐early provitamin A (PVA) lines, classify them into heterotic groups (HGs), identify testers, and determine yield stability of hybrids under contrasting environments in two trials. In Trial 1, 190 F1hybrids plus six checks were tested underStriga‐infested, drought, and stress‐free environments in Nigeria from 2015–2017. In Trial 2, 35 extra‐early yellow hybrids were evaluated under low‐N,Striga‐infested, and stress‐free environments in 2018. TZEEIOR 202 and TZEEIOR 205 had PVA concentrations of 23.98 and 22.56 μg g−1. TZEEIOR 197 × TZEEIOR 205 (20.1 μg g−1) and TZEEIOR 202 × TZEEIOR 205 (22.7 μg g−1) contained about double the PVA level of the commercial check, TZEEI 58 × TZEE‐Y Pop STR C5 (11.4 μg g−1). Both general (GCA) and specific (SCA) combining ability variances were significant for most agronomic traits, although GCA was larger than SCA effects, indicating GCA effects primarily controlled the inheritance of those traits. TZEEIOR 97 and TZEEIOR 197 were identified as inbred testers. TZEEIOR 197 × TZEEIOR 205 was identified as a single‐cross tester and the most stable and highest‐yielding hybrid across environments. TZEEIOR 202 and TZEEIOR 205 should be invaluable resources for breeding for high PVA. Provitamin A level was independent of hybrid yield potential, indicating that selection of superior hybrids with elevated PVA levels should be feasible.
“Cycling of amino‐nitrogen and other nutrients between shoots and roots in cereals—A possible mechanism integrating shoot and root in the regulation of nutrient uptake” by H.D. Cooper and D.T. Clarkson, Journal of Experimental Botany (1989) 40:753–762
Authors: Rufty Thomas W. , Sinclair Thomas R. 
Published: May 2020

AbstractThis article is part of a series of brief commentaries to highlight papers that have resulted in important and distinctly new perspectives in crop science. A criterion for selection of papers is that they must have been published at least 20 yr ago to allow for a long‐range perspective in assessment of the papers. The current article briefly reviews the paper by H.D. Cooper and D.T. Clarkson published in 1989 that offered an original analysis of internal movement of nitrogen in wheat (Triticum aestivum L.). Using 15NO3− fed to a split‐root system, they found that a large fraction of absorbed nitrogen was rapidly cycled around the plant as a result of exchanges between the xylem and phloem. They concluded that cycling in the plant ensured tissues had access to a common pool of soluble nitrogen from which nitrogen could be removed and incorporated into protein depending on the demands of tissue growth. The cycling pool of nitrogen also provided a possible whole‐plant signaling mechanism that coordinates growth activities with the feedback control system regulating nitrate uptake by the root.
Priming effects of phytometabolites and hormones on rooting characteristics in tall fescue exposed to water stress
Authors: Liu Ying , Zhang Juming , Huang Bingru 
Published: May 2020

AbstractExtensive rooting is a key factor regulating plant growth. The objectives of this study were (a) to determine how priming of plants with phytometabolites and hormones, including trehalose (Tre), glycine betaine (GB), spermidine (Spd), brassinolide (BR), and strigolactone (SL), affect rooting characteristics in tall fescue (Festuca arundinacea Schreb.) exposed to water stress, and (b) to identify the effective concentration for each compound affecting root elongation and lateral root proliferation. Roots of seedlings were incubated for 12 h in solutions containing four concentrations of each compound (Tre, GB, Spd, BR, or GR24 [a synthetic analog of SL]) and grown in nutrient solution containing polyethylene glycol 8000 (PEG) solution to induce water stress (−0.5 MPa osmotic potential). Priming of plants with all compounds stimulated root growth under PEG‐induced water stress, and the effects were dose dependent. Glycine betaine at 10 mM and GR24 at 1 μM mainly enhanced main root elongation. Spermidine at 0.1 mM was promotive to main root formation and elongation. Trehalose at 0.3 mM increased main root length, lateral root length and number. Brassinolide at 0.1 nM was effective in stimulating elongation and formation of both main roots and lateral roots. Trehalose, GB, Spd, BR, and SL promoted root growth, but differentially regulated lateral root proliferation or main root elongation in tall fescue exposed to water stress. Future research may investigate whether these compounds may synergistically or coordinately regulate root growth and underlying mechanisms for the differential regulation of main roots and lateral branching by each compound individually or interactively.
The search for alignment of board gender diversity, the adoption of environmental management systems, and the association with firm performance in Asian firms
Authors: Rehman Saif , Orij René , Khan Hashim 
Published: May 2020

AbstractThis study examines how board gender diversity can address the challenges to adopt environment management systems (EMS) to improve firm performance. Firstly, drawing on gender socialization and diversity theories, higher board gender diversity motivates firms to adopt EMS. Empirical evidence shows that firms with gender diverse boards are greener. Secondly, the study investigates the maxim that green pays to be green. The empirical findings highlight a positive and statistically significant but economically modest link between EMS and firm financial performance. However, the inclusion of board gender diversity as moderator significantly improves the relationship between EMS and firm performance. In addition, CEO gender is linked to better performance only in firms with low female board diversity. The findings strongly recommend higher board gender diversity as a mechanism to address the challenges of EMS and firm performance simultaneously. The findings are robust to controlling for propensity score matching technique and are different in different approaches.
Introduction of sacubitril/valsartan in primary care follow‐up of heart failure: a prospective observational study (THESEUS)
Authors: Dieterle Thomas , Schaefer Stefan , Meyer Ina , Ackermann Gabriele , Ahmed Kashan , Hullin Roger 
Published: May 2020

AbstractAimsSwitch from angiotensin converting enzyme inhibitor treatment to sacubitril/valsartan (sac/val) is associated with benefit in heart failure with reduced ejection fraction (HFrEF). Reports on management of this switch are largely based on randomized controlled trials, retrospective analyses, and hospital‐based care, while patients with chronic heart failure (CHF) are frequently followed‐up in primary care. The THESEUS study aimed to characterize the transition to sac/val and early maintenance period of HFrEF in primary care.Method and resultsTHESEUS was a prospective, observational, non‐interventional study, performed at primary care sites throughout Switzerland. Patient characteristics, sac/val transition, and maintenance were reported at study enrolment and approximately 3 and 6 months after sac/val initiation. The primary endpoint was achievement of 200 mg BID sac/val with maintenance for ≥12 weeks. Secondary outcomes included dosing regimens, healthcare utilization in the 6 months prior to sac/val initiation and during the study, patient well‐being, safety, and tolerability. Fifty‐eight patients with CHF were enrolled from 45 primary care centres. Six patients were excluded, and 19 achieved the primary endpoint (36.5%, Achievers). Non‐Achievers underwent fewer titration steps than Achievers (1.9 ± 0.9 vs. 3.1 ± 1.4). In both groups, patient well‐being improved and the percentage of New York Heart Association III patients decreased. Healthcare utilization decreased (19% vs. 30.8% in the 6 months pre‐enrolment period). The most frequent reasons for target dose non‐achievement were asymptomatic and symptomatic hypotension (15.3% and 12.1%, respectively).ConclusionsResults from THESEUS suggest that transition to sac/val is manageable in primary care, with a safety profile corresponding to reports from specialized heart failure care.
Influence of Temperature and Nickel on Algal Biofilm Fatty Acid Composition
Authors: Fadhlaoui Mariem , Laderriere Vincent , Lavoie Isabelle , Fortin Claude 
Published: May 2020

Abstract
Freshwater biofilms play an important role in aquatic ecosystems and are widely used to evaluate environmental conditions. Little is known about the effects of temperature and metals on biofilm fatty acid composition. In the present study, we exposed a natural biofilm cultured in mesocosms to a gradient of nickel (Ni) concentrations at 15 and 21 °C for 28 d. Metal bioaccumulation, algal taxonomic composition, and biofilm fatty acid profiles were determined. At both temperatures, bioaccumulated Ni increased with Ni exposure concentration and reached the highest values at 25 µM Ni, followed by a decrease at 55 and 105 µM Ni. In control biofilms, palmitic acid (16:0), palmitoleic acid (16:1n7), oleic acid (18:1n9), linoleic acid (18:2n6), and linolenic acid (18:3n3) were the dominant fatty acids at 15 and 21 °C. This composition suggests a dominance of cyanobacteria and green algae, which was subsequently confirmed by microscopic observations. The increase in temperature resulted in a decrease in the ratio of unsaturated to saturated fatty acids, which is considered to be an adaptive response to temperature variation. Polyunsaturated fatty acids (PUFAs) tended to decrease along the Ni gradient, as opposed to saturated fatty acids which increased with Ni concentrations. Temperature and Ni affected differently the estimated desaturase and elongase activities (product/precursor ratios). The increase in PUFAs at 15 °C was concomitant to an increase in Δ9-desaturase (D9D). The estimated activities of D9D, Δ12-desaturase, and Δ15-desaturase decreased along the Ni gradient and reflected a decline in PUFAs. The elevated estimated elongase activity reflected the observed increase in saturated fatty acids at the highest Ni exposure concentration (105 µM). Our results suggest that fatty acids could be used as an endpoint to evaluate environmental perturbations. Environ Toxicol Chem 2020;39:1566–1577. © 2020 SETAC
Abstract
The increase in temperature was accompanied by a decrease in the degree of unsaturation. Exposure to nickel also induced a decrease in polyunsaturated fatty acids. The response of biofilms thus revealed and additive effect of the two stressors. Our results highlighted the pertinence of using fatty acids as an endpoint to evaluate environmental perturbations. PUFA = polyunsaturated fatty acid; SFA = saturated fatty acid; UFA = unsaturated fatty acid.
Ibuprofen: Fish Short-Term Reproduction Assay with Zebrafish (Danio rerio) Based on an Extended OECD 229 Protocol
Authors: Constantine Lisa A. , Green John W. , Schneider Suzanne Z. 
Published: May 2020

Abstract
A study was conducted to understand the potential for ibuprofen to impact the hypothalamus-pituitary-gonadal endocrine axis resulting in disruption of fish reproduction. The Good Laboratory Practice study was conducted according to the Organisation for Economic Co-operation and Development 229 Protocol, Fish Short-Term Reproduction Assay, and extended an additional 4 d to evaluate hatching success in the F1 generation. Test organisms were exposed to nominal test concentrations of 0.5, 2.4, 11.5, 55.3, and 265.4 µg ibuprofen/L and a negative control (dilution water). To strengthen the statistical power of the study, twice the number of replicates were used in the negative control versus individual treatment levels. A 21-d pre-exposure to identify groups of actively spawning fish was immediately followed by a 36-d exposure. Results for apical endpoints of survival, growth, and reproduction (fecundity and fertility), as well as the biomarker vitellogenin in the F0 generation and time to hatch and hatching success in the F1 generation are presented. Based on mean measured exposure concentrations and effects on fecundity in the F0 generation and hatching success in the F1 generation, overall no-observed-effect concentration and lowest-observed-effect concentration for the present study were 55.2 and 265.9 µg ibuprofen/L, respectively. Results from the present study indicate a lack of endocrine-mediated reproductive effects in zebrafish at environmentally relevant concentrations of ibuprofen. Environ Toxicol Chem 2020;39:1534–1545. © 2020 SETAC
A smart energy‐based source location privacy preservation model for Internet of Things‐based vehicular ad hoc networks
Authors: Abizar   , Farman Haleem , Jan Bilal , Khan Zahid , Koubaa Anis 
Published: May 2020

AbstractVehicle‐to‐vehicle (V2V) communication aims to improve road safety by periodic exchange of Hello messages. Nowadays, the Internet of Things (IoT) is widely used to solve city transportation problems by employing multihop‐based V2V communication. In IoT‐based vehicular ad hoc networks (VANETs), devices are interconnected with various hardware and software, so the privacy of data, temporal, and location will be at risk due to unauthorized manipulation, especially at intersections in congested urban areas. To address these concerns in IoT‐based VANETs, we proposed a smart energy‐based source location privacy preservation (SESLPP) technique for sustainable urban city roads (ie, intersections). The proposed SESLPP protects the source location privacy while maintaining an accurate reputation based on specific parameters such as trust, speed, distance, and acceleration. A selected node based on these parameters forwards messages and acts as a phantom node to improve the source location privacy within their communication range. The selection of a phantom node is based on a set of parameters, which makes it a multicriteria decision problem. In this article, a multicriteria decision tool known as analytical network process has been used for optimal phantom node selection that improves the source location privacy in an urban scenario by considering intersections. We considered the same parameters (trust, speed, distance, and acceleration) that was used for highway scenario with proper adjustment of their values for an urban area (crossroad intersection point). The proposed SESLPP provides an optimal platform for smart city communication networks.