bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereoselective and Stereospecific Reactions of Cobalt Sandwich Complexes: Synthesis of a New Class of Single Enantiomer Bulky Planar Chiral P−N and P−P Ligands
Authors: Arthurs Ross A. , Horton Peter N. , Coles Simon J. , Richards Christopher J. 
Published: December 2017

AbstractStarting from (η5‐acetylcyclopentadienyl)(η4‐tetraphenylcyclobutadiene)cobalt(I), highly enantioselective (99 % ee) (S)‐CBS catalysed ketone reduction followed by stereospecific alcohol‐azide exchange, azide reduction and dimethyllation gave (R)‐(η5‐α‐N,N‐dimethylaminoethylcyclopentadienyl)(η4‐tetraphenylcyclobutadiene) cobalt(I) (Arthurs’ amine). This underwent highly diastereoselective cyclopalladation to give di‐μ‐acetate‐bis‐(R)‐[(η5‐(Sp)‐2‐(α‐N,N‐dimethylaminoethyl)cyclopentadienyl, 1‐C, N)(η4‐tetraphenylcyclobutadiene)cobalt(I)]dipalladium, and highly diastereoselective lithiation to give (R)‐(η5‐(Sp)‐1‐(α‐N,N‐dimethylaminoethyl)‐2‐(diphenylphosphino)cyclopentadienyl)(η4‐tetraphenylcyclobutadiene)cobalt(I) (PPCA) following the addition as electrophile of chlorodiphenylphosphine. This PN‐ligand was converted into (R)‐(η5‐(Sp)‐1‐(α‐dicyclohexylphosphinoethyl)‐2‐(diphenylphosphino)cyclopentadienyl)(η4‐tetraphenylcyclobutadiene)cobalt(I), a PP‐ligand (Rossiphos), by stereospecific amine‐phosphine exchange using HPCy2. These air‐stable P−N and P−P complexes are the first examples of a new class of bulky planar chiral ligands for application in asymmetric catalysis.
Aggregation Pathways of Native‐Like Ubiquitin Promoted by Single‐Point Mutation, Metal Ion Concentration, and Dielectric Constant of the Medium
Authors: Fermani Simona , Calvaresi Matteo , Mangini Vincenzo , Falini Giuseppe , Bottoni Andrea , Natile Giovanni , Arnesano Fabio 
Published: December 2017

AbstractUbiquitin‐positive protein aggregates are biomarkers of neurodegeneration, but the molecular mechanism responsible for their formation and accumulation is still unclear. Possible aggregation pathways of human ubiquitin (hUb) promoted by both intrinsic and extrinsic factors, are here investigated. By a computational analysis, two different hUb dimers are indicated as possible precursors of amyloid‐like structures, but their formation is disfavored by an electrostatic repulsion involving Glu16 and other carboxylate residues present at the dimer interface. Experimental data on the E16V mutant of hUb shows that this single‐point mutation, although not affecting the overall protein conformation, promotes protein aggregation. It is sufficient to shift the same mutation by only two residues (E18V) to regain the behavior of wild‐type hUb. The neutralization of Glu16 negative charge by a metal ion and a decrease of the dielectric constant of the medium by addition of trifluoroethanol (TFE), also promote hUb aggregation. The outcomes of this research have important implications for the prediction of physiological parameters that favor aggregate formation.
Switching Multivalent DNA Complexation using Metal‐Controlled Cationic Supramolecular Self‐Assemblies
Authors: Drożdż Wojciech , Bessin Yannick , Gervais Virginie , Cao Xiao‐Yu , Lehn Jean‐Marie , Stefankiewicz Artur R. , Ulrich Sébastien 
Published: December 2017

AbstractWe provide a proof‐of‐principle that coordination chemistry drives the in situ self‐assembly of an inactive ligand into a multivalent cluster capable of effectively complexing DNA. We show that metal coordination and scavenging can be used to switch the multivalency of the system. Thus, controlled DNA complexation and decomplexation could be achieved.
Do You Get What You See? Understanding Molecular Self‐Healing
Authors: Geitner Robert , Legesse Fisseha‐Bekele , Kuhl Natascha , Bocklitz Thomas W. , Zechel Stefan , Vitz Jürgen , Hager Martin , Schubert Ulrich S. , Dietzek Benjamin , Schmitt Michael , Popp Jürgen 
Published: December 2017

AbstractThe self‐healing ability of self‐healing materials is often analyzed using morphologic microscopy images. Here it was possible to show that morphologic information alone is not sufficient to judge the status of a self‐healing process and molecular information is required as well. When comparing molecular coherent anti‐Stokes Raman scattering (CARS) and morphological laser reflection images during a standard scratch healing test of an intrinsic self‐healing polymer network, it was found that the morphologic closing of the scratch and the molecular crosslinking of the material do not take place simultaneously. This important observation can be explained by the fact that the self‐healing process of the thiol‐ene based polymer network is limited by the mobility of alkene‐containing compounds, which can only be monitored by molecular CARS microscopy and not by standard morphological imaging. Additionally, the recorded CARS images indicate a mechanochemical activation of the self‐healing material by the scratching/damaging process, which leads to an enhanced self‐healing behavior in the vicinity of the scratch.
Unexplored Areas of Direct Solvolytic Liquefaction of Lignocellulosic Biomass
Authors: Bahlo Rune L. , Hursthouse Andrew S. , Sievers Anika , Willner Thomas 
Published: December 2017

AbstractMost research on direct solvolytic liquefaction (DSL) focuses on hydrothermal liquefaction or organic model solvents and is dominated by catalytic processes. This review highlights the much less understood aspects of non‐catalytic DSL including the solvent recycling required for continuous processing. Results from earlier studies indicate both the feasibility of recycling and the non‐catalytic suppression of char formation. However, a proof of continuous operation under steady state with a stationary solvent composition and an extensive investigation of process parameters are missing to date.
A Kinetic Study of Methane Partial Oxidation over Fe‐ZSM‐5 Using N2O as an Oxidant
Authors: Chow Ying Kit , Dummer Nicholas F. , Carter James H. , Meyer Randall J. , Armstrong Robert D. , Williams Christopher , Shaw Greg , Yacob Sara , Bhasin Madan M. , Willock David J. , Taylor Stuart H. , Hutchings Graham J. 
Published: December 2017

AbstractCatalytic methane oxidation using N2O was investigated at 300 °C over Fe‐ZSM‐5. This reaction rapidly produces coke (retained organic species), and causes catalyst fouling. The introduction of water into the feed‐stream resulted in a significant decrease in the coke selectivity and an increase in the selectivity to the desired product, methanol, from ca. 1 % up to 16 %. A detailed investigation was carried out to determine the fundamental effect of water on the reaction pathway and catalyst stability. The delplot technique was utilised to identify primary and secondary reaction products. This kinetic study suggests that observed gas phase products (CO, CO2, CH3OH, C2H4 and C2H6) form as primary products whilst coke is a secondary product. Dimethyl ether was not detected, however we consider that the formation of C2 products are likely to be due to an initial condensation of methanol within the pores of the zeolite and hence considered pseudo‐primary products. According to a second order delplot analysis, coke is considered a secondary product and its formation correlates with CH3OH formation. Control experiments in the absence of methane revealed that the rate of N2O decomposition is similar to that of the full reaction mixture, indicating that the loss of active alpha‐oxygen sites is the likely cause of the decrease in activity observed and water does not inhibit this process.
Solubility‐Modifying Power of Zwitterionic Salts
Authors: Level Gaelle , Vieira Fadul Mariana , Blesic Marijana 
Published: December 2017

AbstractThe separation of small, hydrophilic molecules from aqueous solutions on one side and the dissolution of hydrophobic organic molecules in water on the other are nowadays among the most difficult challenges in chemical and bio‐technology. Even though these two tasks are seemingly of opposite nature, it is demonstrated herein that both processes can be facilitated by addition of zwitterionic salts, a new class of compounds that can act either as a solubility enhancer or a phase‐separation promoter depending on the structure of the solute dissolved in an aqueous solution. At a more fundamental level, this study investigates the salting in/out propensity of the ions and supports the importance of both salt–solute interaction and their concentration.
The cognitive–behavioural model of hoarding disorder: Evidence from clinical and non‐clinical cohorts
Authors: Kyrios Michael , Mogan Christopher , Moulding Richard , Frost Randy O. , Yap Keong , Fassnacht Daniel B. 
Published: December 2017

The cognitive–behavioural model of hoarding disorder incorporates information processing difficulties, maladaptive attachment to possessions, erroneous beliefs about the nature of possessions, and mood problems as etiologically significant factors, although developmental experiences such as a compromised early family environment have also been proposed in an augmented model. This study examined the specificity and relevance of variables highlighted in the augmented cognitive–behavioural model. Various clinical participants (n = 89) and community controls (n = 20) were assessed with structured clinical interviews to verify diagnosis. Participants completed self‐report measures of hoarding severity, cognitions, meta‐memory, and early developmental experiences (e.g., memories of warmth and security in one's family). Hoarding cohorts (with and without obsessive–compulsive disorder) reported poor confidence in memory, but relative to other groups (obsessive–compulsive disorder without hoarding disorder, anxiety disorders, and healthy controls), hoarding‐relevant cognitions, need to keep possessions in view, and concerns about the consequences of forgetting were significantly higher. Hoarding groups reported the lowest recollections of warmth in their family, although no differences were found between hoarding and non hoarding clinical cohorts for uncertainty about self and others. Nonetheless, clinical cohorts reported generally higher scores of uncertainty than healthy controls. When predicting hoarding severity, after controlling for age and mood, recollections of lack of warmth in one's family was a significant predictor of hoarding severity, with hoarding‐related cognitions and fears about decision‐making being additional unique predictors. The study supports the augmented cognitive–behavioural model of hoarding, inclusive of the importance of early developmental influences in hoarding.
Toward a hierarchical and architecture‐based virtual machine allocation in cloud data centers
Authors: Rahmanian Ali Asghar , Horri Abbas , Dastghaibyfard Gholamhossein 
Published: December 2017

SummaryNumber of cloud data centers which consists of hundreds of hosts has increased tremendously around the world due to increase in demands for cloud services. It is expected energy consumption of data centers will reach 139.8 billion Kwh by 2020. Many algorithms are proposed to reduce energy consumption as well as service level agreement violationby minimizing the number of active hosts. Current proposed algorithms do not consider data center architecture, the physical position of hosts, and energy consumption of numerous switches that are in data centers. In this paper, a novel hierarchical cloud resource management is proposed that not only minimizes the number of hosts but also aggregates virtual machines on a limited subset of data center racks and modules to minimize energy consumption. Experimental results with Cloudsim show that our proposed algorithm reduces energy consumption up to 26% and service level agreement violation up to 96%.
Model for autonomous agents in machine‐to‐machine navigation networks
Authors: Ali Anum , Shah Ghalib , Aslam Muhammad 
Published: December 2017

SummaryMachine‐to‐machine (M2M) is an evolving architecture and tends to provide enormous services through the swarm presence of the networked devices. Localization is one of those services. Previous localization techniques require complex computation that is not suitable and affordable in such architecture. Moreover, integrating intelligent multiagents on these ubiquitous devices makes the network more independent and reactive requiring for a less complex localization model. This paper reviews the present localization techniques and discusses their infeasibility for M2M communication while proposing a mathematical model that is derived from Anderson model for the distributed structure of machine‐type‐communication network involving autonomous agents. This paper has made an attempt to use the property of Anderson model that structures the distributed objects. This paper also classifies autonomous agents according to their functionalities in a navigational network. Recently, Anderson model have been customized for implication of optical communication; in this paper, the proposed mathematical model involves intelligent agents for localization that aim to reduce complexity of positioning computations for nodes having restricted computational resources and battery life, which are the main characteristics of M2M communication.
Pollinator‐mediated selection on floral size and tube color inLinum pubescens: Can differential behavior and preference in different times of the day maintain dimorphism?
Authors: Lebel Merav , Obolski Uri , Hadany Lilach , Sapir Yuval 
Published: December 2017

AbstractDiversity of flower traits is often proposed as the outcome of selection exerted by pollinators. Positive directional pollinator‐mediated selection on floral size has been widely shown to reduce phenotypic variance. However, the underlying mechanism of maintaining within‐population floral color polymorphism is poorly understood. Divergent selection, mediated by different pollinators or by both mutualists and antagonists, may create and maintain such polymorphism, but it has rarely been shown to result from differential behavior of one pollinator. We tested whether different behaviors of the same pollinators in morning and evening are associated with dimorphic floral trait inLinum pubescens,a Mediterranean annual plant that exhibits variable within‐population frequencies of dark‐ and light‐colored flower tubes.Usia bicolorbee‐flies, the major pollinators ofL. pubescens, are mostly feeding in the flower in the morning, while in the evening they are mostly visiting the flowers for mating. In 2 years of studyingL. pubescensin a single large population in the Carmel, Israel, we found in one year that dark‐centered flowers received significantly higher fraction of visits in the morning. Fitness was positively affected by number of visits, but no fitness differences were found between tube‐color morphs, suggesting that both morphs have similar pollination success. Using mediation analysis, we found that flower size was under positive directional pollinator‐mediated selection in both years, but pollinator behavior did not explain entirely this selection, which was possibly mediated also by other agents, such as florivores or a‐biotic stresses. While most pollinator‐mediated selection studies show that flower size signals food reward, inL. pubescens, it may also signal for mating place, which may drive positive selection. While flower size found to be under pollinator‐mediated selection inL. pubescens, differential behavior of the pollinators in morning and evening did not seem to explain flower color polymorphism.
Age‐associated B cells expanded in autoimmune mice are memory cells sharing H‐CDR3‐selected repertoires
Authors: Aranburu Alaitz , Höök Nina , Gerasimcik Natalija , Corleis Bjorn , Ren Weicheng , Camponeschi Alessandro , Carlsten Hans , Grimsholm Ola , Mårtensson Inga‐Lill 
Published: December 2017

AbstractAge‐associated B cells (ABCs) represent a distinct cell population expressing low levels of CD21 (CD21−/low). The Ig repertoire expressed by ABCs in aged mice is diverse and exhibits signs of somatic hypermutation (SHM). A CD21−/low B‐cell population is expanded in autoimmune diseases, e.g. systemic lupus erythematosus, as well as in lupus‐prone NZB/W mice and in mice lacking a pre‐B cell receptor (SLC−/−). However, the nature of the CD21−/low B cells (hereafter ABCs) in autoimmunity is not well understood. Here we show that in young SLC−/− mice, the vast majority of the ABCs express memory B‐cell (MBC) markers in contrast to wild‐type controls. A similar population is present in lupus‐prone MRL mice before and at disease onset. In SLC−/− mice, a majority of the ABCs are IgM+, their VH genes have undergone SHM, show clonal diversification and clonal restriction at the H‐CDR3 level. ABC hybridomas, established from SLC−/− mice, secrete typical lupus autoantibodies, e.g. anti‐Smith antigen, and some of those that bind to DNA comprise a H‐CDR3 that is identical to previously described IgM anti‐DNA antibodies from lupus‐prone mice. Together, these results reveal that ABCs in autoimmune mice are comprised of autoreactive MBCs expressing highly restricted H‐CDR3 repertoires.
Better models are more effectively connected models
Authors:   Connecteur WG3 Think‐Tank Team, Nunes João Pedro , Wainwright John , Bielders Charles L. , Darboux Frédéric , Fiener Peter , Finger David , Turnbull Laura 
Published: December 2017

AbstractWater‐ and sediment‐transfer models are commonly used to explain or predict patterns in the landscape at scales different from those at which observations are available. These patterns are often the result of emergent properties that occur because processes of water and sediment transfer are connected in different ways. Recent advances in geomorphology suggest that it is important to consider, at a specific spatio‐temporal scale, the structural connectivity of system properties that control processes, and the functional connectivity resulting from the way those processes operate and evolve through time. We argue that a more careful consideration of how structural and functional connectivity are represented in models should lead to more robust models that are appropriate for the scale of application and provide results that can be upscaled. This approach is necessary because, notwithstanding the significant advances in computer power in recent years, many geomorphic models are still unable to represent the landscape in sufficient detail to allow all connectivity to emerge. It is important to go beyond the simple representation of structural connectivity elements and allow the dynamics of processes to be represented, for example by using a connectivity function. This commentary aims to show how a better representation of connectivity in models can be achieved, by considering the sorts of landscape features present, and whether these features can be represented explicitly in the model spatial structure, or must be represented implicitly at the subgrid scale. Copyright © 2017 John Wiley & Sons, Ltd.
Main sedimentary sequences and stages of major cratonic basins during the breakup of Rodinia
Authors: Wu Xiangfeng , Xu Shumei , Wu Shan , Li Sanzhong , Wang Dahua , Xiao Yongjun , Wang Jinduo , Somerville Ian 
Published: December 2017

This paper summarizes the main sedimentary sequences of major cratonic basins during the breakup of Rodinia and the assembly of Gondwana and extracts evolutionary stages of the Neoproterozoic basins around the Paleo‐Pacific Ocean and Iapetus Ocean tracts. During the breakup of Rodinia, sedimentary sequences and evolutionary stages of the main basins in major cratonic blocks, such as Yangtze, Australia, Eastern American, Western American, and Western Africa cratons, mostly experienced intracratonic rifting, drifting or passive continental margin, carbonate platform construction, and foreland basin stages. The time of rifting to drifting transition in Congo‐São‐Francisco precisely marked the closure of the Adamastor Ocean between Congo‐São‐Francisco and Rio de la Plata and presaged the opening of the Iapetus Ocean. The time of rifting to drifting transition of Eastern American of Laurentia and West Africa initiated at ~580 Ma also signified the opening of the Iapetus Ocean. The time of drifting stage of the main basins around the Paleo‐Pacific Ocean tracts is not only earlier than those of the Iapetus Ocean tracts but also is characterized by diachronism. The time of drifting onset of basins in the Yangtze Block is ~720 Ma, the time of drifting initiation of the Adelaide Fold Belt in South Australia is 680 Ma, and the time of drifting stage of the south‐western margin of Laurentia occurred at 550 Ma. The different times of rifting to drifting transition of the Adelaide Fold Belt in South Australia, the Yangtze Craton, and Western American of Laurentia signified the nonisochronous opening of the Neoproterozoic Paleo‐Pacific Ocean.
Constitutive downregulation protein kinase C epsilon in hSOD1G93A astrocytes influences mGluR5 signaling and the regulation of glutamate uptake
Authors: Vergouts Maxime , Doyen Pierre J , Peeters Michael , Opsomer Remi , Hermans Emmanuel 
Published: December 2017

AbstractAccumulating evidence indicates that motor neuron degeneration in amyotrophic lateral sclerosis (ALS) is a non‐cell‐autonomous process and that impaired glutamate clearance by astrocytes, leading to excitotoxicity, could participate in progression of the disease. In astrocytes derived from an animal model of ALS (hSOD1G93A rats), activation of type 5 metabotropic glutamate receptor (mGluR5) fails to increase glutamate uptake, impeding a putative dynamic neuroprotective mechanism involving astrocytes. Using astrocyte cultures from hSOD1G93A rats, we have demonstrated that the typical Ca2+ oscillations associated with mGluR5 activation were reduced, and that the majority of cells responded with a sustained elevation of intracellular Ca2+ concentration. Since the expression of protein kinase C epsilon isoform (PKCɛ) has been found to be considerably reduced in astrocytes from hSOD1G93A rats, the consequences of manipulating its activity and expression on mGluR5 signaling and on the regulation of glutamate uptake have been examined. Increasing PKCɛ expression was found to restore Ca2+ oscillations induced by mGluR5 activation in hSOD1G93A‐expressing astrocytes. This was also associated with an increase in glutamate uptake capacity in response to mGluR5 activation. Conversely, reducing PKCɛ expression in astrocytes from wild‐type animals with specific PKCɛ‐shRNAs was found to alter the mGluR5 associated oscillatory signaling profile, and consistently reduced the regulation of the glutamate uptake‐mediated by mGluR5 activation. These results suggest that PKCɛ is required to generate Ca2+ oscillations following mGluR5 activation, which support the regulation of astrocytic glutamate uptake. Reduced expression of astrocytic PKCɛ could impair this neuroprotective process and participate in the progression of ALS.