bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonadaptive Genetic Change in Human and Primate Evolution
Authors: Meyer Diogo , Harris Eugene E 
Published: April 2013

AbstractEvolutionary change can occur by nonadaptive processes, such as random genetic drift, and as a consequence of selection on linked genetic variants. In addition, if selective regimes change over time, an allele currently at a high frequency because of past fitness advantage may be suboptimal for its present environment. Small effective population size along the human lineage increased the influence of drift, rendering mutations with slight effects on fitness effectively neutral. Demographic events like spatial expansions and population bottlenecks shape most of the genetic variation within and among modern populations. Natural selection itself may also contribute to nonadaptive or maladaptive change by increasing the frequency of linked deleterious variants. Also, certain maladaptive alleles may have increased in frequency because of compensating fitness advantages they provide.Key Concepts:Reduced effective population size along the human lineage led to an increase in the influence of genetic drift and a reduction in the efficacy of natural selection, especially for mutations with small selective effects. Evidence for this can be seen in comparisons of measures of natural selection in lineages having different effective population sizes.Genome‐wide variation within and between human populations can be almost entirely explained by random drift and demographic forces other natural selection.Spatial expansions in human evolutionary history may cause gene surfing, in which low frequency alleles at the wave of advance can reach high frequencies and spread over large areas merely due to the effects of intense genetic drift. Nonadaptive gene surfing might be a better explanation than adaptive evolution for some high frequency, widespread genetic variants.Population bottlenecks in human evolutionary history can lead to increases in drift and reductions in the efficacy of purifying selection. This leads to an increase in the fraction of slightly deleterious mutations present in human populations that have experienced recent bottlenecks.Natural selection on alleles can result in nonadaptive shifts in the frequencies of alleles that are closely linked to them. Such linkage effects can lead to the increased frequencies of mildly deleterious alleles if they are linked to a beneficial variant, and can interfere with the effectiveness of adaptive evolution in promoting an advantageous allele if it is linked to a deleterious allele.Caution should be exercised in interpreting patterns of genetic variation in human populations as being adaptive without thoroughly ruling out nonadaptive explanations.
Crystalline CoFeB/Graphite Interfaces for Carbon Spintronics Fabricated by Solid Phase Epitaxy
Authors: Wong P. K. Johnny , van Geijn Elmer , Zhang Wen , Starikov Anton A. , Tran T. Lan Anh , Sanderink Johnny G. M. , Siekman Martin H. , Brocks Geert , Kelly Paul J. , van der Wiel Wilfred G. , de Jong Michel P. 
Published: April 2013

AbstractStructurally ordered interfaces between ferromagnetic electrodes and graphene or graphite are of great interest for carbon spintronics, since they allow spin‐filtering due to k‐vector conservation. By solid phase epitaxy of amorphous/nanocrystalline CoFeB at elevated temperatures, the feasibility of fabricating crystalline interfaces between a 3d ferromagnetic alloy and graphite is demonstrated, without suffering from the unwetting problem that was commonly seen in many previous studies with 3d transition metals. The films fabricated on graphite in this way are found to have a strong body‐centered‐cubic (110) texture, albeit without a unique, well‐defined in‐plane epitaxial relationship with the substrate lattice. Using various X‐ray spectroscopic techniques, it is shown that boron suppresses the formation of CoFe‐O during CoFeB deposition, and then diffuses out of the CoFe lattice. Segregation of B occurred exclusively to the film surface upon in situ annealing, and not to the interface between CoFeB and graphite. This is favorable for obtaining a high spin polarization at the hybrid CoFe/graphite crystalline interface. The Co and Fe spin moments in the crystalline film, determined by X‐ray magnetic circular dichroism, are found to be bulk‐like, while their orbital moments show an unusual giant enhancement which has yet to be understood.
Steady state modeling and simulation of the Oleflex process for isobutane dehydrogenation considering reaction network
Authors: Farsi M. , Jahanmiri A. , Rahimpour M. R. 
Published: April 2013

ABSTRACTIn this study, the performance of moving bed radial flow reactors in Olefex technology to produce isobutene from isobutane dehydrogenation is studied at steady state condition. The dehydrogenation reactors have been modeled heterogeneously on the basis of the mass and energy governing laws considering a two‐dimensional model. In this system, isobutane dehydrogenation, hydrogenolysis, propane dehydrogenation, and coke formation reactions occur on the catalyst surface. The coke deposition on the catalyst surface and the catalyst velocity along the axial direction result to an activity profile along reactors that has been calculated from proper correlation. To prove the accuracy of the considered mathematical model and assumptions, simulation results are compared with the plant data at the same process condition. The isobutane conversion and isobutene selectivity have been obtained at about 38.53% and 90.76%, respectively, which have good agreement with the plant data. © 2013 Curtin University of Technology and John Wiley & Sons, Ltd.
Reactions of 13‐Vertex Carboranes with Strong Bases: Synthesis and Structural Characterization of Carborane Monoanions with exo‐π Bonding
Authors: Zheng Fangrui , Zhang Jian , Fu Xiaodu , Xie Zuowei 
Published: April 2013

AbstractSeveral monoanions of 13‐vertex carboranes were prepared in high yields from the reactions of C,C′‐linked 13‐vertex carboranes with tBuOK or NaH in dry THF at room temperature. These monoanions were characterized by various spectroscopic methods, elemental analysis, and single‐crystal X‐ray diffraction. The results showed substantial double‐bond character between the cage‐carbon atom and the exo vicinal carbon atom, thus leading to charge delocalization into the cage. As a result, the atomatom distances within the cage were elongated, with one broken CB bond. However, the cage geometry of the monoanions remained very similar to that of their corresponding neutral 13‐vertex closo‐carboranes. These monoanions represent the first examples of 13‐vertex carboranes with exo‐π bonding to hypercarbon atoms.
Design of Robust Discrete‐Time Observer‐Based Repetitive‐Control System
Authors: Zhou Lan , She Jinhua , Zhou Shaowu , Wu Min 
Published: April 2013

AbstractThis paper concerns the design of a robust discrete‐time observer‐based repetitive‐control system for a class of linear plants with periodic uncertainties. A discrete two‐dimensional model is built that partially uncouples the control and learning actions of a repetitive‐control system, enabling their preferential adjustment. The combination of a singular‐value decomposition of the output matrix and Lyapunov stability theory is used to derive a linear‐matrix‐inequality‐based design algorithm that determines the control and state‐observer gains. A numerical example illustrates the main advantage of the method: easy, preferential adjustment of control and learning by means of two tuning parameters in an linear‐matrix‐inequality‐based condition.
Improvement of grand multi‐model ensemble prediction skills for the coupled models of APCC/ENSEMBLES using a climate filter
Authors: Lee Doo Young , Ahn Joong‐Bae , Ashok Karumuri , Alessandri Andrea 
Published: April 2013

AbstractTwelve coupled model simulations of two multi‐model ensemble (MME) systems for boreal winters from 1983 to 2005 are used to improve the climate prediction. From grading the relative capability of each simulation in reproducing the observed link between the tropical El Niño‐Southern Oscillation (ENSO)‐related Walker circulation and the Pacific rainfall, we find an optimal MME suite with improved prediction skills. This study demonstrates that the climate filter concept, proposed by us in a recent work, is not only useful in improving the MME prediction skills as compared to a single MME system, but also the skills of a grand MME that encompasses two well‐performing MMEs.
Characteristics improvement of calcium hydroxide dental cement by hydroxyapatite nanoparticles. Part 1: Formulation and microstructure
Authors: Yasaei Mana , Zamanian Ali , Moztarzadeh Fathollah , Ghaffari Maryam , Mozafari Masoud 
Published: April 2013

AbstractCalcium hydroxide cement (CHC), which is a direct pulp‐capping material, has been widely used for several decades. In spite of the well‐known advantages of CHCs, they have some disadvantages as well, such as high solubility, no inherent adhesive qualities, and low mechanical strength. Previous studies were undertaken to improve these deficiencies by implementing changes to modify the conventional CHCs. The aim of the present research is to demonstrate the potential rectification of the aforementioned deficiencies of the commercially available CHCs by adding hydroxyapatite (HA) nanoparticles without lessening their advantages. Here, the synthesized HA nanoparticles were added into the CHCs in two different portions of 3 and 7 wt%. A scanning electron microscope was used to observe and analyze the microstructure, and X‐ray energy dispersive analysis was used to analyze the elemental composition of the new CHCs. In addition, setting time, mechanical strength, pH, calcium (Ca) release, and antibacterial behavior were measured to assess how HA nanoparticles influence the characteristics of CHCs. The results showed that adding 3 wt% HA nanoparticles can optimally improve the mechanical strength of the cement and increase the Ca release rate as a mineralization promoter without reducing the antibacterial behavior.
President's page
Authors: Dillon Andrew 
Published: April 2013

AbstractEditor's SummaryAs the president of the newly renamed Association for Information Science & Technology, Dillon recognizes critical behind‐the‐scenes work being done to improve ASIS&T from the inside out. The Task Force on Web Presence will develop a plan to enhance internal communications and to keep information current and easy to find. Developing a moderated discussion forum on information will help solidify the organization's position as a thought leader. An information resource on what information professionals do will help define the field for public viewers and solicit thoughts on careers and opportunities. Recognizing the value of volunteer involvement, input and assistance, Dillon invites all ASIS&T members to participate actively at this turning point for the global association.
Open access and altmetrics: Distinct but complementary
Authors: Mounce Ross 
Published: April 2013

AbstractEditor's SummaryOpen access to publications through electronic journals has dramatically expanded downloading and use of this literature and spurred the rise of alternative metrics to assess article impact. Open access publications have been shown to gain more citations than articles with restricted access, and seven of the 10 most popular articles in 2012 were free public access with the most response, as documented through altmetrics, coming from non‐scientists. Altmetrics also enables post‐publication filtering and peer review in a nearly immediate timeframe for very large open access journals. Online activity measured through altmetrics highlights attention to the article on its own, less dependent on the validation of a journal name. The field of altmetrics is young, still limited to certain open websites, but with potential for considerable expansion, development and application. Open access and altmetrics can be expected to grow in a complementary and mutually supportive manner.
Collaborative annotation for scientific data discovery and reuse
Authors: Borne Kirk 
Published: April 2013

AbstractEditor's SummaryHuman classification alone, unable to handle the enormous quantity of project data, requires the support of automated machine‐based strategies. In collaborative annotation, humans and machines work together, merging editorial strengths in semantics and pattern recognition with the machine strengths of scale and algorithmic power. Discovery informatics can be used to generate common data models, taxonomies and ontologies. A proposed project of massive scale, the Large Synoptic Survey Telescope (LSST) project, will systematically observe the southern sky over 10 years, collecting petabytes of data for analysis. The combined work of professional and citizen scientists will be needed to tag the discovered astronomical objects. The tag set will be generated through informatics and the collaborative annotation efforts of humans and machines. The LSST project will demonstrate the development and application of a classification scheme that supports search, curation and reuse of a digital repository.
CNT‐Supported MoxC Catalysts: Effect of Loading and Carburization Parameters
Authors: Frank Benjamin , Friedel Klaus , Girgsdies Frank , Huang Xing , Schlögl Robert , Trunschke Annette 
Published: April 2013

AbstractMoxC/CNT catalysts were prepared through carburization of an oxidic molybdenum precursor impregnated on multiwalled carbon nanotubes (CNTs). The effects of different carburization atmospheres, heating rates, and molybdenum loadings were tested. The catalysts were characterized by using CO temperature‐programmed desorption, XRD, N2physisorption, SEM, and TEM. The catalytic performance in the steam reforming of methanol was used as a sensitive probe to indicate changes in the catalyst surface during the catalytic action. Contrary to the bulk MoxC catalysts, the heating rate during carburization has no effect on the catalysts. Instead, molybdenum loading and carburization atmosphere are the key factors for catalyst structure and performance. The molybdenum‐based activity decreases at loadings >10 wt % at a constant product selectivity. The CO2/CH4product ratio indicates changes in the catalyst properties at the loadings <20 wt %, at which the activity is constant. Carburization in 20 % CH4/H2yields 2 nm sized crystallites of cubic α‐MoC. Carburization in pure H2and He yields hexagonal β‐Mo2C with a larger particle size. Both phases show different catalytic performances in terms of activity and CO2/CH4selectivity. Thus, a multiparameter toolbox for fine‐tuning of catalyst properties is presented.
A Combined Kinetic and Thermodynamic Approach for the Interpretation of Continuous‐Flow Heterogeneous Catalytic Processes
Authors: Bortolini Olga , Cavazzini Alberto , Giovannini Pier Paolo , Greco Roberto , Marchetti Nicola , Massi Alessandro , Pasti Luisa 
Published: April 2013

AbstractThe heterogeneous proline‐catalyzed aldol reaction was investigated under continuous‐flow conditions by means of a packed‐bed microreactor. Reaction‐progress kinetic analysis (RPKA) was used in combination with nonlinear chromatography for the interpretation, under synthetically relevant conditions, of important mechanistic aspects of the heterogeneous catalytic process at a molecular level. The information gathered by RPKA and nonlinear chromatography proved to be highly complementary and allowed for the assessment of optimal operating variables. In particular, the determination of the rate‐determining step was pivotal for optimizing the feed composition. On the other hand, the competitive product inhibition was responsible for the unexpected decrease in the reaction yield following an apparently obvious variation in the feed composition. The study was facilitated by a suitable 2D instrumental arrangement for simultaneous flow reaction and online flow‐injection analysis.
Methylidene Rare‐Earth‐Metal Complex Mediated Transformations of CN, NN and NH Bonds: New Routes to Imido Rare‐Earth‐Metal Clusters
Authors: Hong Jianquan , Zhang Lixin , Wang Kai , Zhang Yin , Weng Linhong , Zhou Xigeng 
Published: April 2013

AbstractThree new patterns of reactivity of rare‐earth metal methylidene complexes have been established and thus have resulted in access to a wide variety of imido rare‐earth metal complexes [L3Ln3(μ2‐Me)3(μ3‐Me)(μ‐NR)] (L=[PhC(NC6H3iPr2‐2,6)2]−; R=Ph, Ln=Y (2 a), Lu (2 b); R=2,6‐Me2C6H3, Ln=Y (3 a), Lu (3 b); R=p‐ClC6H4, Ln=Y (4 a), Lu (4 b); R=p‐MeOC6H4, Ln=Y (5 a), Lu (5 b); R=Me2CHCH2CH2, Ln=Y (6 a), Lu (6 b)) and [{L3Lu3(μ2‐Me)3(μ3‐Me)}2(μ‐NR′N)] (R′=(CH2)6 (7 b), (C6H4)2 (8 b)). Complex 2 b was treated with an excess of CO2 to give the corresponding carboxylate complex [L3Lu3(μ‐η1:η1‐O2CCH3)3(μ‐η1:η2‐O2C‐CH3)(μ‐η1:η1:η2‐O2CNPh)] (9 b) easily. Complex 2 a could undergo the selective μ3‐Me abstraction reaction with phenyl acetylene to give the mixed imido/alkynide complex [L3Y3(μ2‐Me)3(μ3‐η1:η1:η3‐NPh)(μ3‐CCPh)] (10 a) in high yield. Treatment of 2 with one equivalent of thiophenol gave the selective μ3‐methyl‐abstracted products [L3Ln3(μ2‐Me)3(μ3‐η1:η1:η3‐NPh)(μ3‐SPh)] (Ln=Y (11 a); Lu (11 b). All new complexes have been characterized by elemental analysis, NMR spectroscopy, and most of the structures confirmed by X‐ray diffraction.
A Versatile and Robust Vesicle Based on a Photocleavable Surfactant for Two‐Photon‐Tuned Release
Authors: Dong Jianming , Xun Zhiqing , Zeng Yi , Yu Tianjun , Han Yongbin , Chen Jinping , Li Ying‐Ying , Yang Guoqiang , Li Yi 
Published: April 2013

AbstractA small amphiphile that contains a coumarin unit and alkynyl groups, as a two‐photon‐cleavable segment and polymerizable groups, respectively, was designed and synthesized. The amphiphile showed a critical aggregation concentration of about 4.6×10−5 M and formed a vesicle‐type assembly. The formed vesicles were stabilized by in situ “click” polymerization without altering their morphology. Hydrophobic and hydrophilic guests can be encapsulated within the vesicle membrane and inside the aqueous core of the vesicle, respectively. The loaded guests can be released from the vesicle by using UV or near‐IR stimuli, through splitting up the amphiphilic structure of the amphiphile. Distinguished dose‐controlled photorelease of the polymeric vesicle is achieved with the maintenance of vesicular integrity, which makes the guest release dependent on the amount of cleavage of the amphiphilic structure during irradiation. This study provides a potential strategy for the development of versatile and stable drug‐delivery systems that offer sustained and photo‐triggered release.
Total Synthesis of Nominal Gobienine A
Authors: Kondoh Azusa , Arlt Alexander , Gabor Barbara , Fürstner Alois 
Published: April 2013

AbstractThe lichen‐derived glycoconjugate gobienine A is structurally more complex than most glycolipids isolated from higher plants by virtue of the all‐cis substituted γ‐lactone substructure embedded into its macrocyclic frame. A concise entry into this very epimerization‐prone and hence challenging structural motif is presented, which relies on an enantioselective cyanohydrin formation, an intramolecular Blaise reaction, a palladium‐catalyzed alkoxycarbonylation, and a diastereoselective hydrogenation of the tetrasubstituted alkene in the resulting butenolide. This strategy, in combination with ring‐closing olefin metathesis for the formation of the macrocyclic perimeter, allowed the proposed structure of gobienine A (1) to be formed in high overall yield. The recorded spectral data show that the structure originally attributed to gobienine A is incorrect and that it is not the epimerization‐prone ester site on the butanolide ring that is the locus of misassignment; rather, the discrepancy must be more profound.
MAO Inhibitory Activity of 2‐Arylbenzofurans versus 3‐Arylcoumarins: Synthesis, in vitro Study, and Docking Calculations
Authors: Ferino Giulio , Cadoni Enzo , Matos Maria João , Quezada Elias , Uriarte Eugenio , Santana Lourdes , Vilar Santiago , Tatonetti Nicholas P. , Yáñez Matilde , Viña Dolores , Picciau Carmen , Serra Silvia , Delogu Giovanna 
Published: April 2013

AbstractMonoamine oxidase (MAO) is an important drug target for the treatment of neurological disorders. Several 3‐arylcoumarin derivatives were previously described as interesting selective MAO‐B inhibitors. Preserving the trans‐stilbene structure, a series of 2‐arylbenzofuran and corresponding 3‐arylcoumarin derivatives were synthesized and evaluated as inhibitors of both MAO isoforms, MAO‐A and MAO‐B. In general, both types of derivatives were found to be selective MAO‐B inhibitors, with IC50 values in the nano‐ to micromolar range. 5‐Nitro‐2‐(4‐methoxyphenyl)benzofuran (8) is the most active compound of the benzofuran series, presenting MAO‐B selectivity and reversible inhibition (IC50=140 nM). 3‐(4′‐Methoxyphenyl)‐6‐nitrocoumarin (15), with the same substitution pattern as that of compound 8, was found to be the most active MAO‐B inhibitor of the coumarin series (IC50=3 nM). However, 3‐phenylcoumarin 14 showed activity in the same range (IC50=6 nM), is reversible, and also severalfold more selective than compound 15. Docking experiments for the most active compounds into the MAO‐B and MAO‐A binding pockets highlighted different interactions between the derivative classes (2‐arylbenzofurans and 3‐arylcoumarins), and provided new information about the enzyme–inhibitor interaction and the potential therapeutic application of these scaffolds.
Homogeneous Electrochemical Detection of Hippuric Acid in Urine Based on the Osmium–Antigen Conjugate
Authors: Jeon Won‐Yong , Choi Young‐Bong , Kim Hyug‐Han 
Published: April 2013

AbstractA homogeneous electrochemical immunoassay is based on the interaction of osmium–antigen conjugate with its antibody. The novelty presented herein is the direct conjugation of the osmium complex to a small antigen and the application of the quantitative analysis of the antigen and its antibody as the electrical signal for homogeneous immunoassay. The small antigen chosen is hippuric acid (HA), a major urinary metabolite in toluene‐exposed humans. As a redox mediator, [Os(4,4′‐dimethoxy‐2,2′‐bipyridine)2(4‐aminomethylpyridine‐HA)Cl]+/2+ (Os‐HA antigen) has been synthesized and characterized on screen‐printed carbon electrodes. The synthesized Os‐HA antigen shows reversible redox peaks at E1/2=0.056 V versus Ag/AgCl. The homogeneous competitive immunoassay relies on the interaction between Os‐HA antigen conjugate and free antigen to its antibody, which can generate electrical signals linearly proportional to the free antigen monitored by cyclic voltammetry and differential pulse voltammetry in the range of 10 μg mL−1 to 5.12 mg mL−1. The cutoff concentration of HA in urine samples is 2.0 mg mL−1, so the method can be used to develop a HA immunosensor. Moreover, the proposed homogeneous electrochemical immunoassay method can be applied to detect low concentrations of small antigens found in the healthcare area.