bluuebunny/crossref_metadata_2025_split huggingface dataset:
The role of cold cues at different life stages on germination and flowering phenology
Authors: Rubin Matthew J. , Friedman Jannice 
Published: April 2018

Premise of the StudyThe timing of major phenological transitions is critical to lifetime fitness, and life history theory predicts differences for annual and perennial plants. To correctly time these transitions, many plants rely on environmental cues such as exposure to extended periods of cold, which may occur at different stages throughout their lifetime.MethodsWe studied the role of cold at different life stages, by jointly exposing seed (stratification) and rosettes (vernalization) to cold. We used 23 populations of Mimulus guttatus, which vary from annuals to perennials, and investigated how cold at one or both stages affected germination, flowering, growth, and biomass.Key ResultsWe found that stratification and vernalization interact to affect life cycle transitions, and that cold at either stage could synchronize flowering phenology. For perennials, either stratification or vernalization is necessary for maximum flowering. We also found that germination timing covaried with later traits. Moreover, plants from environments with dissimilar climates displayed different phenological responses to stratification or vernalization.ConclusionsIn general, cold is more important for seed germination in annuals and plants from environments with warm temperatures and variable precipitation. In contrast, cold is more important for flowering in perennials: it accelerates flowering in plants from lower precipitation environments, and it increases flowering proportion in plants from cooler, more stable precipitation environments. We discuss our findings in the context of the variable environments plants experience within a population and the variation encountered across the biogeographic native range of the species.
Toxicity of the spiny thick‐foot Pachypodium
Authors: Agrawal Anurag A. , Ali Aliya , Daisy Johnson M. , Hastings Amy P. , Burge Dylan , Weber Marjorie G. 
Published: April 2018

Premise of the StudyPachypodium (Apocynaceae) is a genus of iconic stem‐succulent and poisonous plants endemic to Madagascar and southern Africa. We tested hypotheses about the mode of action and macroevolution of toxicity in this group. We further hypothesized that while monarch butterflies are highly resistant to cardenolide toxins (a type of cardiac glycoside) from American Asclepias, they may be negatively affected by Pachypodium defenses, which evolved independently.MethodsWe grew 16 of 21 known Pachypodium spp. and quantified putative cardenolides by HPLC and also by inhibition of animal Na+/K+‐ATPase (the physiological target of cardiac glycosides) using an in vitro assay. Pachypodium extracts were tested against monarch caterpillars in a feeding bioassay. We also tested four Asclepias spp. and five Pachypodium spp. extracts, contrasting inhibition of the cardenolide‐sensitive porcine Na+/K+‐ATPase to the monarch's resistant form.Key ResultsWe found evidence for low cardenolides by HPLC, but substantial toxicity when extracts were assayed on Na+/K+‐ATPases. Toxicity showed phylogenetic signal, and taller species showed greater toxicity (this was marginal after phylogenetic correction). Application of Pachypodium extracts to milkweed leaves reduced monarch growth, and this was predicted by inhibition of the sensitive Na+/K+‐ATPase in phylogenetic analyses. Asclepias extracts were 100‐fold less potent against the monarch compared to the porcine Na+/K+‐ATPase, but this difference was absent for Pachypodium extracts.ConclusionsPachypodium contains potent toxicity capable of inhibiting sensitive and cardenolide‐adapted Na+/K+‐ATPases. Given the monarch's sensitivity to Pachypodium, we suggest that these plants contain novel cardiac glycosides or other compounds that facilitate toxicity by binding to Na+/K+‐ATPases.
Computational and Experimental Evidence of Two Competing Thermal Electrocyclization Pathways for Vinylheptafulvene
Authors: Frandsen Benjamin N. , Skov Anders B. , Cacciarini Martina , Brøndsted Nielsen Mogens , Kjaergaard Henrik G. 
Published: April 2018

AbstractThe thermal electrocyclic ring‐closure reaction of vinylheptafulvene (VHF) to form dihydroazulene (DHA) is elucidated herein by using DFT and 1H NMR spectroscopy. Two different transition states were found computationally; one corresponds to a disrotatory pathway, which is allowed according to the Woodward–Hoffmann selection rules, whereas the other corresponds to a conrotatory pathway. The conrotatory pathway is found to be zwitterionic in the transition state, whereas the disrotatory transition state varies in zwitterionic character depending on solvent and substituents in the molecular framework. The conrotatory and disrotatory transition states are found to have similar energy and their relative stability varies with solvent polarity and functionalization at the C1 position. To support these findings, we chemically ring‐opened diastereomerically pure 1‐(benzothiazol‐2‐yl)‐DHA to give the VHF form, then subsequently thermally reconverted the VHF to DHA in a range of solvents with various polarities. We found that, depending on solvent polarity, different ratios of anti‐ and syn‐diastereoisomers of DHA were formed in a systematic manner, which supports the existence of two distinct thermal ring‐closure pathways for VHF.
Biodegradable bioadhesive nanoparticle incorporation of broad‐spectrum organic sunscreen agents
Authors: Suh Hee‐Won , Lewis Julia , Fong Linda , Ramseier Julie Ying , Carlson Kacie , Peng Zheng‐Hong , Yin Emily Sara , Saltzman W. Mark , Girardi Michael 
Published: April 2018

AbstractConventional emulsion‐based sunscreen formulations are limited by postapplication epicutaneous penetration that increases the risk of allergic dermatitis, cellular damage, and filter photodegradation upon ultraviolet radiation (UVR) exposure. Encapsulation of the UVB filter padimate O within bioadhesive biodegradable nanoparticles (BNPs) composed of poly(d,l‐lactic acid)‐hyperbranched polyglycerol was previously shown to enhance UVR protection while preventing skin absorption. Herein, we assess the capacity of BNP co‐incorporation of avobenzone and octocrylene to provide broad‐spectrum UVR protection. The ratio of UV filters within nanoparticles (NPs) was optimized for filter–filter stabilization upon UV irradiation and maximum drug loading. In vitro water‐resistance test showed significant particle retention at 85% over 3 hr. In a pilot clinical study, protection against UVR‐induced erythema of BNPs was found to be comparable to the FDA standard P2. Thus, sunscreen formulations utilizing BNP incorporation of a combination of organic filters may offer key safety and performance advantages.
Simplified hybrid algorithms for pressure wire interrogation exploiting advantages of a baseline and contrast Pd/Pa ratio indexes to predict stenosis significance: Insight from the SPARE multicenter prospective study
Authors: Cerrato E. , Tomassini F. , Salinas P. , Pavani M. , Conrotto F. , Echavarria‐Pinto M. , Macaya F. , Quadri G. , D'Ascenzo F. , Quirós Alicia , Varbella F. , Escaned J. 
Published: April 2018

AbstractBackgroundSimplification of functional stenosis assessment with pressure guidewires may facilitate adoption of physiology‐guided revascularization. An important step in this regard is the avoidance of hyperemic agents, required for fractional flow reserve (FFR) calculation. We evaluate the merits of a hybrid algorithms that combines the translesional pressure ratio (Pd/Pa) obtained at rest, after contrast medium injection (cFFR) and after adenosine administration (FFR).Methods and ResultsEighty‐six patients with 108 de novo intermediate coronary stenoses were included in this prospective, multicenter study. Using prespecified cut‐off values that correctly identified stenosis with a 95% of agreement (<0.89 and >0.96 for Pd/Pa; <0.84 and > 0.87 for cFFR) we tested the efficiency of three different multi‐step strategies combining the three indices to classify stenosis severity, using FFR‐only measurement as reference. All three different hybrid algorithms (Pd/Pa‐FFR; cFFR‐FFR; Pd/Pa‐cFFR‐FFR) have more than 95% of agreement with FFR. Yet, the novel Pd/Pa‐cFFR‐FFR hybrid strategy demonstrated the best performance, avoiding the need of adenosine and medium contrast in 90% and 48% of cases, respectively.ConclusionsA hybrid Pd/Pa‐cFFR‐FFR decision‐making algorithm could be an alternative and valuable strategy to increase the adoption of a physiology‐guided PCI using conventional pressure guidewires and consoles.
Experiments and Simulations for Horizontal Pneumatic Transport of Dry Drill Cuttings
Authors: Malagalage Anjana , Ariyaratne W. K. Hiromi , Ratnayake Chandana , Melaaen Morten C. 
Published: April 2018

AbstractInvestigation of the possibility of using a pneumatic conveying technique for the transportation of dry drill cuttings is the main objective of this study. Both pilot‐scale experimental and simulation approaches were carried out for sand, which was used as a model material that mimics the properties of dry drill cuttings. Simulations based on the multiphase particle‐in‐cell method, which is a Eulerian‐Lagrangian model, were used to predict the pressure drop, and the predictions are in good agreement with the experimental results. Both approaches supported the possibility of using a pneumatic conveying technique for the transportation of dry drill cuttings under the tested conditions. The study provides the foundation for further analysis of the pneumatic conveyance of wet drill cuttings.
Development and Application of Asymmetric Organocatalytic Mukaiyama and Vinylogous Mukaiyama‐Type Reactions
Authors: Frías María , Cieślik Wioleta , Fraile Alberto , Rosado‐Abón Anielka , Garrido‐Castro Alberto F. , Yuste Francisco , Alemán José 
Published: April 2018

AbstractOrganocatalysis is a growing area that is benefiting from advances in many fields. Its implementation has begun in areas such as supramolecular chemistry, organic chemistry and natural product synthesis. While a considerable number of important publications in the field of organocatalytic Mukaiyama‐type additions have been reported, they are yet to be fully covered in a review. Therefore, we would like to highlight the applications of various kinds of organocatalysts in Mukaiyama‐type reactions, while also including the vinylogous Mukaiyama variation. Herein we describe and discuss the development and current state of the art of the organocatalytic Mukaiyama reaction, vinylogous Mukaiyama and related reactions.
Axonal neurofilaments exhibit frequent and complex folding behaviors
Authors: Fenn J. Daniel , Monsma Paula C. , Brown Anthony 
Published: April 2018

AbstractNeurofilaments are flexible cytoskeletal polymers that are capable of folding and unfolding between their bouts of bidirectional movement along axons. Here we present a detailed characterization of this behavior in cultured neurons using kymograph analysis with approximately 30 ms temporal resolution. We analyzed 781 filaments ranging from 0.6‐42 µm in length. We observed complex behaviors including pinch folds, hairpin folds, orientation changes (flips), and occasional severing and annealing events. On average, the filaments spent approximately 40% of their time in some sort of folded configuration. A small proportion of filaments (4%) moved while folded, but most (96%) moved in an outstretched configuration. Collectively, our observations suggest that motors may interact with neurofilaments at multiple points along their length, but preferentially at their ends. In addition, the prevalence of neurofilament folding and the tendency of neurofilaments to straighten out when they move, suggest that an important function of the movement of these polymers in axons may be to maintain them in an outstretched and longitudinally co‐aligned configuration. Thus, neurofilament movement may function as much to organize these polymers as to move them, and this could explain why they spend so much time engaged in apparently unproductive bidirectional movement.
Opening Furan for Tailoring Properties of Bio‐based Poly(Furfuryl Alcohol) Thermoset
Authors: Falco Guillaume , Guigo Nathanael , Vincent Luc , Sbirrazzuoli Nicolas 
Published: April 2018

AbstractThis work shows how furan ring‐opening reactions were controlled by polymerization conditions to tune the cross‐link density in bio‐based poly(furfuryl alcohol) (PFA). The influence of water and isopropyl alcohol (IPA) on the polymerization of furfuryl alcohol, and particularly on furan ring‐opening, was investigated by means of13C NMR and FT–IR spectroscopy. Results indicated that formation of open structures were favored in the presence of solvents, thus leading to modification of the thermo‐mechanical properties compared to PFA cross‐linked without solvent. Dynamic mechanical analyses showed that when slightly more open structures were present in PFA it resulted in an important decrease of the cross‐link density. Despite lower glass‐transition temperature and lower elastic modulus for PFA polymerized with solvent, the thermal stability remains very high (>350 °C) even with more open structures in PFA.
Label‐free Electrochemical Aptasensor for Jurkat Cells Detection as a Potential Diagnostic Tool for Leukemia
Authors: Bábelová Lenka , Sohová Marianna Eliášová , Poturnayová Alexandra , Buríková Monika , Bizík Jozef , Hianik Tibor 
Published: April 2018

AbstractElectrochemical impedance spectroscopy (EIS) and thickness shear mode acoustic method (TSM) have been used for development of the aptamer‐based biosensor for detection leukemic Jurkat cells. Thiolated DNA aptamers specific to the cancer marker protein tyrosine kinase‐7 (PTK7) have been chemisorbed on a gold surface. Redox probe [Fe(CN)6]3−/4− has been used for monitoring changes in charge transfer resistance, Rct, in EIS experiments. Rct increased with increasing the concentration of Jurkat cells. TSM allowed label‐free detection based on decrease of resonant frequency following addition of the cells. We obtained high sensitivity of Jurkat cells determination with limit of detection (LOD) 105±10 and 463±50 cells/mL for electrochemical and acoustic sensor, respectively. Small non‐specific interactions have been observed for control U266 cells which can be particularly due to the interaction of the aptamers with lipid part of the biomembranes.
Biophysical measurement of red blood cells by laboratory on print circuit board chip
Authors: Zhao Ying , Zhang Wengeng 
Published: April 2018

AbstractMicrofluidic impedance pulse sensor has emerged as an easily handled and low‐cost platform in the electrical analysis of biological cells. In the conventional method, impedance sensor demanded expensive patterning metal electrodes on the substrate, which are directly in touch with electrolytes in order to measure the microfluidic channel impedance change. In this article, a cost‐effective microfluidic impedance sensor built upon a dielectric film coated printed circuit board is introduced. Impedance electrodes are protected by a dielectric film layer from electrochemical erosion between electrodes and electrolyte. Human red blood cells from adult and neonatal were utilized to demonstrate the feasibility of the proposed device in the electroanalysis of biological cells.
Combined optimization of N‐terminal site‐specific PEGylation of recombinant hirudin using response surface methodology and kinetic analysis
Authors: Wang Xudong , Wang Shuchang , Pan Duotao , Qin Kairong , Yuan Hengli , Zhang Fengying , Sun Yundong , Xiu Zhilong 
Published: April 2018

AbstractIn this study, a combined optimization method was developed to optimize the N‐terminal site‐specific PEGylation of recombinant hirudin variant‐2 (HV2) with different molecular weight mPEG‐propionaldehyde (mPEG‐ALD), which is a multifactor‐influencing process. The HV2‐PEGylation with 5 kDa mPEG‐ALD was first chosen to screen significant factors and determine the locally optimized conditions for maximizing the yield of mono‐PEGylated product using combined statistical methods, including the Plackett–Burman design, steepest ascent path analysis, and central composition design for the response surface methodology (RSM). Under the locally optimized conditions, PEGylation kinetics of HV2 with 5, 10, and 20 kDa mPEG‐ALD were further investigated. The molar ratio of polyethylene glycol to HV2 and reaction time (the two most significant factors influencing the PEGylation efficiency) were globally optimized in a wide range using kinetic analysis. The data predicted by the combined optimization method using RSM and kinetic analysis were in good agreement with the corresponding experiment data. PEGylation site analysis revealed that almost 100% of the obtained mono‐PEGylated‐HV2 was modified at the N‐terminus of HV2. This study demonstrated that the developed method is a useful tool for the optimization of the N‐terminal site‐specific PEGylation process to obtain a homogeneous mono‐PEGylated protein with desirable yield.
Den Weltenwandel gestalten
Authors: Strohschneider Peter 
Published: April 2018

AbstractDigitalisierung und Digitalität verändern die Welt und verändern die Wissenschaften – mit unabsehbaren Erkenntnischancen, aber auch enormen Herausforderungen. Ihnen muss sich nicht zuletzt die wissenschaftsgeleitete Forschungsförderung stellen.
Blick in den viralen Baukasten
Authors: Willbold Dieter , Hoffmann Silke 
Published: April 2018

AbstractAnhand der HIV‐Infektion wollen Strukturbiologen die Wechselbeziehungen zwischen dem krank machenden Virus und seinem Wirt besser verstehen. Ergeben sich daraus neue therapeutische Ansätze? In jedem Fall Einsichten in grundlegende Zellmechanismen.
Biochemical and biophysical studies of Helicobacter pylori arginine decarboxylase, an enzyme important for acid adaptation in host
Authors: Alam Mashkoor , Srivastava Abhishek , Dutta Ankita , Sau Apurba Kumar 
Published: April 2018

AbstractDespite importance of arginine decarboxylase (ADC: EC 4.1.1.19) of Helicobacter pylori (H. pylori) 26695 pathogenic strain for acid adaptation in host, the enzyme has not yet been studied at a molecular level. Using combined approaches that include kinetic assays, site‐directed mutagenesis, circular dichroism, heat‐induced denaturation, analytical gel‐filtration, and homology modeling, we report here a detailed investigation of H. pylori ADC. The pyridoxal 5′‐phosphate (PLP)‐dependent enzyme exhibits higher catalytic activity in the presence of Mg2+ ions at pH ∼8.5. Unlike other bacterial ADCs, this homolog exists as a hexamer. The higher thermal stability (Tm ∼65.8 ± 0.2 °C) of the enzyme observed from the heat‐induced circular dichroism measurements indicates its secondary structural stabilization in the presence of PLP. The kinetic parameters Km and kcat of the enzyme are determined to be 3.4 ± 0.2 mM and 55.2 ± 1.0 min−1, respectively. We elucidate that Cys487, a conserved residue located at the active‐site, is involved in the catalysis, whose pKa value was estimated to be ∼7.2. The homology model of the protein show conserved α/β TIM barrel and β‐sandwich domains, which are characteristic features of fold III decarboxylases. A lower sequence identity (∼21%) of this enzyme compared with its human counterpart has enabled us to screen putative inhibitors of H. pylori ADC. We found that α‐difluoromethylarginine inhibits the activity of the H. pylori enzyme competitively with a Ki value ∼118 µM and thus it can serve as a basis to design inhibitors with higher efficacy against this ADC. © 2018 IUBMB Life, 70(7):658–669, 2018
Biological effects of Ni(II) on monocytes and macrophages in normal and hyperglycemic environments
Authors: Chana Monica , Lewis Jill B. , Davis Ryan , Elam Yolanda , Hobbs David , Lockwood Petra E. , Wataha John C. , Messer Regina L. 
Published: April 2018

AbstractCorrosion and release of nickel ions from biomedical alloys are well documented, but little is still known about the effects of released nickel ions on cellular function with recurrent inflammatory challenges. Evidence suggests Ni(II) ions amplify LPS‐induced secretion of several pro‐inflammatory cytokines from monocytes. Exacerbating the inflammatory response, hyperglycemic conditions also affect monocytic function. This study investigated how Ni(II) and hyperglycemic conditions, both singly and in combination, alter monocyte proliferation, mitochondrial activity, inflammatory responses, and differentiation. Results showed that Ni(II) did not affect proliferation, but decreased mitochondrial activity in monocytic‐cells and macrophages under normal conditions. However, hyperglycemic conditions negated the toxicity seen with Ni(II) exposure. Cytokine secretion in response to LPS was variable, with little effect on IL6 secretion, but significantly increased secretion of IL1β at intermediate Ni(II) concentrations. Hyperglycemic conditions did not alter these results significantly. Finally, exposure to eluants from nickel‐based commercial alloys caused enhanced IL1β secretion from PMA‐treated cells. These data suggest that corrosion products from nickel‐containing dental alloys increased Ni(II)‐induced changes in cytokine secretion by monocytes and macrophages. By better defining the effects of Ni(II) at these lower, biomedically relevant concentrations, we improve understanding of the biomedical alloy risk in the context of dental inflammation. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A:2433–2439, 2018.
The action of the etale fundamental group scheme on the connected component of the essentially finite one
Authors: Hai Phùng Hô , dos Santos João Pedro P. 
Published: April 2018

AbstractWe follow the pattern in [14, Section 4] to define an action of the etale fundamental group scheme on the local component of the essentially finite fundamental group scheme of Nori. We show that the associated representation is faithful when X is a curve of genus ⩾2.
Impact of relational benefits on trust in the Asian context: Alternative model testing with satisfaction as a mediator and relationship age as a moderator
Authors: Fatima Johra Kayeser , Mascio Rita Di , Johns Raechel 
Published: April 2018

AbstractAlthough it is an established phenomenon in the literature that relational benefits have many positive outcomes, the comparative effect of each type of benefit on different types of trust when customer satisfaction is the mediator, in particular in the Asian context, remains unexplored in the services literature. Therefore, this study, using several alternative models, aims to identify the impacts of confidence benefit, social benefit, and specific treatment benefit on competence, contractual, and goodwill trust, along with an investigation of the mediation impact of customer satisfaction. The study also explores the moderation impact of relationship age on the relational benefits–customer satisfaction relationship. The study's findings from partial least squares‐based structural equation modeling analysis confirmed that ensuring confidence benefit produces a higher level of competence trust and contractual trust in comparison to that achieved by social benefit and special treatment benefit, whereas the latter two types of benefit are crucial for developing goodwill trust. Although customer satisfaction was found to be a significant mediator between relational benefits and the three dimensions of trust, the moderation effect of relationship age was not significant in any model. The study's managerial and theoretical implications are presented in the final section of the paper.