bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Triclosan on Self‐Assembly of Alkyl Ammonium Surfactants Adsorbed within Montmorillonite Galleries in Silicone Elastomer Composites
Authors: Liauw Christopher M. , Taylor Rebecca L. , Munro Lindsey J. , Wilkinson Arthur N. , Cheerarot Onanong 
Published: April 2014

SummaryPoly(propylene) homopolymer/fly ash (50% wt) composites have been prepared from two samples of fly ash that differ in terms of the geographic source of coal feedstock, which left one of the samples with a higher group I and II metal content. A screening study indicated that Lubrizol Solplus® C800 (an unsaturated carboxylic acid dimer coupling agent), initiated with dicumyl peroxide, conferred the best strength–toughness balance to the composites. In some cases, however this was related to detachment of the interfacial region due to possible extraction of PP‐C800 adduct‐group I and II ion reaction products. Interfacial adhesion was arguably too high in the case of the fly ash sample bearing a lower level of group I and II ions. These deductions were also supported by DSC data.
Probing the the Glass Transition of Atactic Polystyrene Thin Films Using Fiber Optic Refractometry
Authors: Giordano M. , Russo M. , Zarrelli M. , Cusano A. , Antonucci V. 
Published: April 2014

SummaryAn high resolution optical technique based on the film fiber optic refractometer has been used to investigate the effect of the thickness on the glass transition dynamic of Atactic Polystyrene films in the range 20–120 nm. The thermo‐optic behavior of a set of layers dip coated onto the fiber has been analyzed upon cooling from long term equilibrated melt state. The glassy transition temperature is observed to be thickness‐independent as did both the width and the lower and upper bounds of the transition itself. At lowering the thickness of the film the relevant effect is the reduction of the “contrast” between the melt equilibrium phase and the glassy state. A double layers model where a surface soft layer (3.9 nm at 418 K) do not contribute to the glass dynamic retaining liquid features even at temperature well below the glass transition, while the core layer shows a bulk glass transition, is able to quantitatively reproduce reflectance experimental data.
Mechanical Properties of Magneto‐Sensitive Elastomers in a Homogeneous Magnetic Field: Theory and Experiment
Authors: Ivaneyko D. , Toshchevikov V. , Borin D. , Saphiannikova M. , Heinrich G. 
Published: April 2014

SummaryThe aim of this study is to present a microscopic theory which describes the mechanical behaviour of magneto‐sensitive elastomers (MSEs) under a uniform external magnetic field. For this we use a model where magnetic particles are located on the sites of the regular rectangular lattice. We introduce a structure parameter to describe isotropic, chain‐like and plane‐like particle distributions. Our theory is based on the equation for free energy as a function of strain. The magneto‐induced deformation and the shear modulus are calculated as functions of the magnetization. It is shown that interaction between the magnetic particles results in the contraction of an elastomer along the homogeneous magnetic field. With increasing magnetic field the shear modulus for the shear deformation perpendicular to the magnetic field increases for all spatial distributions of magnetic particles. Furthermore, we have compared our result for the shear modulus to the experimental data and found good agreement.
Unfolding study of a trimeric membrane protein AcrB
Authors: Ye Cui , Wang Zhaoshuai , Lu Wei , Wei Yinan 
Published: April 2014

AbstractThe folding of a multi‐domain trimeric α‐helical membrane protein, Escherichia coli inner membrane protein AcrB, was investigated. AcrB contains both a transmembrane domain and a large periplasmic domain. Protein unfolding in sodium dodecyl sulfate (SDS) and urea was monitored using the intrinsic fluorescence and circular dichroism spectroscopy. The SDS denaturation curve displayed a sigmoidal profile, which could be fitted with a two‐state unfolding model. To investigate the unfolding of separate domains, a triple mutant was created, in which all three Trp residues in the transmembrane domain were replaced with Phe. The SDS unfolding profile of the mutant was comparable to that of the wild type AcrB, suggesting that the observed signal change was largely originated from the unfolding of the soluble domain. Strengthening of trimer association through the introduction of an inter‐subunit disulfide bond had little effect on the unfolding profile, suggesting that trimer dissociation was not the rate‐limiting step in unfolding monitored by fluorescence emission. Under our experimental condition, AcrB unfolding was not reversible. Furthermore, we experimented with the refolding of a monomeric mutant, AcrBΔloop, from the SDS unfolded state. The CD spectrum of the refolded AcrBΔloop superimposed well onto the spectra of the original folded protein, while the fluorescence spectrum was not fully recovered. In summary, our results suggested that the unfolding of the trimeric AcrB started with a local structural rearrangement. While the refolding of secondary structure in individual monomers could be achieved, the re‐association of the trimer might be the limiting factor to obtain folded wild‐type AcrB.
Structure of vaccinia virus A46, an inhibitor of TLR4 signaling pathway, shows the conformation of VIPER motif
Authors: Kim Yongwoon , Lee Hasup , Heo Lim , Seok Chaok , Choe Jungwoo 
Published: April 2014

AbstractVaccinia virus (VACV) encodes many proteins that interfere with the host immune system. Vaccinia virus A46 protein specifically targets the BB‐loop motif of TIR‐domain‐containing proteins to disrupt receptor:adaptor (e.g., TLR4:MAL and TLR4:TRAM) interactions of the toll‐like receptor signaling. The crystal structure of A46 (75–227) determined at 2.58 Å resolution showed that A46 formed a homodimer and adopted a Bcl‐2‐like fold similar to other VACV proteins such as A52, B14, and K7. Our structure also revealed that VIPER (viral inhibitory peptide of TLR4) motif resides in the α1‐helix and six residues of the VIPER region were exposed to surface for binding to target proteins. In vitro binding assays between wild type and six mutants A46 (75–227) and full‐length MAL identified critical residues in the VIPER motif. Computational modeling of the A46:MAL complex structure showed that the VIPER region of A46 and AB loop of MAL protein formed a major binding interface. In summary, A46 is a homodimer with a Bcl‐2‐like fold and VIPER motif is believed to be involved in the interaction with MAL protein based on our binding assays.
Role of connecting loop I in catalysis and allosteric regulation of human glucokinase
Authors: Martinez Juliana A. , Larion Mioara , Conejo Maria S. , Porter Carol M. , Miller Brian G. 
Published: April 2014

AbstractGlucokinase (GCK, hexokinase IV) is a monomeric enzyme with a single glucose binding site that displays steady‐state kinetic cooperativity, a functional characteristic that affords allosteric regulation of GCK activity. Structural evidence suggests that connecting loop I, comprised of residues 47–71, facilitates cooperativity by dictating the rate and scope of motions between the large and small domains of GCK. Here we investigate the impact of varying the length and amino acid sequence of connecting loop I upon GCK cooperativity. We find that sequential, single amino acid deletions from the C‐terminus of connecting loop I cause systematic decreases in cooperativity. Deleting up to two loop residues leaves the kcat value unchanged; however, removing three or more residues reduces kcat by 1000‐fold. In contrast, the glucose K0.5 and KD values are unaffected by shortening the connecting loop by up to six residues. Substituting alanine or glycine for proline‐66, which adopts a cis conformation in some GCK crystal structures, does not alter cooperativity, indicating that cis/trans isomerization of this loop residue does not govern slow conformational reorganizations linked to hysteresis. Replacing connecting loop I with the corresponding loop sequence from the catalytic domain of the noncooperative isozyme human hexokinase I (HK‐I) eliminates cooperativity without impacting the kcat and glucose K0.5 values. Our results indicate that catalytic turnover requires a minimal length of connecting loop I, whereas the loop has little impact upon the binding affinity of GCK for glucose. We propose a model in which the primary structure of connecting loop I affects cooperativity by influencing conformational dynamics, without altering the equilibrium distribution of GCK conformations.
Active site conformational changes upon reaction intermediate biotinyl‐5'‐AMP binding in biotin protein ligase from Mycobacterium tuberculosis
Authors: Ma Qingjun , Akhter Yusuf , Wilmanns Matthias , Ehebauer Matthias T. 
Published: April 2014

AbstractProtein biotinylation, a rare form of post‐translational modification, is found in enzymes required for lipid biosynthesis. In mycobacteria, this process is essential for the formation of their complex and distinct cell wall and has become a focal point of drug discovery approaches. The enzyme responsible for this process, biotin protein ligase, substantially varies in different species in terms of overall structural organization, regulation of function and substrate specificity. To advance the understanding of the molecular mechanism of biotinylation in Mycobacterium tuberculosis we have biochemically and structurally characterized the corresponding enzyme. We report the high‐resolution crystal structures of the apo‐form and reaction intermediate biotinyl‐5'‐AMP‐bound form of M. tuberculosis biotin protein ligase. Binding of the reaction intermediate leads to clear disorder‐to‐order transitions. We show that a conserved lysine, Lys138, in the active site is essential for biotinylation.
Prospects for decadal climate prediction in the Mediterranean region
Authors: Guemas Virginie , García‐Serrano Javier , Mariotti Annarita , Doblas‐Reyes Francisco , Caron Louis‐Philippe 
Published: April 2014

AbstractThe Mediterranean region stands as one of the most sensitive to climate change, both in terms of warming and drying. On shorter time‐scales, internal variability has substantially affected the observed climate and in the next decade might enhance or compensate long‐term trends. Here we compare the multi‐model climate predictions produced within the framework of the CMIP5 (Coupled Model Intercomparison Project Phase 5) project with historical simulations to assess the level of multi‐year climate prediction skill in the Mediterranean region beyond that originating from the model accumulated response to the external radiative forcings. We obtain a high and significant skill in predicting 4‐year averaged annual and summer mean temperature over most of the study domain and in predicting precipitation for the same seasons over northern Europe and sub‐Saharan Africa. A lower skill is found during the winter season but still positive for temperature. Although most of this high skill originates from the model response to the external radiative forcings, the initialization contributes to the temperature skill over the Mediterranean Sea and surrounding land areas. The high and significant correlations between the observed Mediterranean temperatures and the observed Atlantic multidecadal oscillation (AMO) in the summer and annual means are captured by the CMIP5 ensemble which suggests that the added skill is related to the ability of the CMIP5 ensemble to predict the AMO. Such a link to the AMO seems restricted to western Africa and summer means only for the precipitation case.
Ten years of ENVISAT observations at ECMWF: A review of activities and lessons learnt
Authors: Dragani R. , Abdalla S. , Engelen R. J. , Inness A. , Thépaut J.‐N. 
Published: April 2014

AbstractIn 2002, the European Space Agency (ESA) launched theENVIromentalSATellite(ENVISAT), which carried ten instruments to provide continuous observation of Earth's land, atmosphere, oceans and ice caps. During the satellite's lifetime, the European Centre for Medium Range Weather Forecasts (ECMWF) has routinely monitored a variety of products from many of its instruments. A subset of these data has also been assimilated in the ECMWF operational system, along with two of its applications: the reanalysis and the Monitoring Atmospheric Composition and Climate (MACC) systems. This article reviews those activities and summarizes the lessons learnt in monitoring and assimilating data from a research satellite within a numerical weather prediction system. The value of continuous data monitoring and the benefits that a close collaboration between data provider and data user can bring to both parties are highlighted. For observations that were assimilated, impact assessments on the ECMWF products have been performed periodically. Two cases are presented in this article. The first one shows that the assimilation of ocean wave information can reduce the wave‐height model random error by up to 8% at the analysis time, with benefits at later forecast times extending to up to 5 days in the Tropics. The second example shows that the assimilation of two ENVISAT ozone products improves the agreement of the ozone analyses with independent ozone observations obtained from sondes and the Microwave Limb Sounder. Finally, the use of ENVISAT reprocessed data is presented, with an emphasis on the importance of data reprocessing and long‐term data preservation as key activities to ensure the future usage of these datasets.
Is high fetal nuchal translucency associated with submicroscopic chromosomal abnormalities on array CGH?
Authors: Huang J. , Poon L. C. , Akolekar R. , Choy K. W. , Leung T. Y. , Nicolaides K. H. 
Published: April 2014

ABSTRACTObjectiveTo examine the possible association between high fetal nuchal translucency thickness (NT) and pathogenic chromosomal copy number variants (CNVs) detected by array comparative genomic hybridization (CGH) in pregnancies with normal fetal karyotype.MethodsArray CGH was carried out in stored samples of chorionic villi from 215 singleton pregnancies resulting in live births in which chorionic villus sampling at 11–13 weeks' gestation for high fetal NT (≥ 3.5 mm) had demonstrated normal karyotype.ResultsMedian fetal NT was 4.0 (range, 3.5–9.5) mm. Array CGH detected additional CNVs in 1.4% (95% CI, 0.5–4.0) of the cases, but none of these was a known pathogenic CNV.ConclusionHigh fetal NT in the absence of sonographically detectable defects may not be associated with pathogenic CNVs. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
The roles of DAZL in RNA biology and development
Authors: Smorag Lukasz , Xu Xingbo , Engel Wolfgang , Pantakani D.V. Krishna 
Published: April 2014

RNA‐binding proteins play an important role in the regulation of gene expression by modulating translation and localization of specific messenger RNAs (mRNAs) during early development and gametogenesis. The DAZ (Deleted in Azoospermia) family of proteins, which includes DAZ, DAZL, and BOULE, are germ cell‐specific RNA‐binding proteins that are implicated in translational regulation of several transcripts. Of particular importance is DAZL, which is present in vertebrates and arose from the duplication of the ancestral BOULE during evolution. Identification of DAZL target mRNAs and characterization of the RNA‐binding sequence through in vitro binding assays and crystallographic studies revealed that DAZL binds to GUU triplets in the 3′ untranslated region of target mRNAs. Although there is compelling evidence for the role of DAZL in translation stimulation of target mRNAs, recent studies indicate that DAZL can also function in translational repression and transport of specific mRNAs. Furthermore, apart from the well‐characterized function of DAZL in gametogenesis, recent data suggest its role in early embryonic development and differentiation of pluripotent stem cells toward functional gametes. In light of the mounting evidence for the role of DAZL in various cellular and developmental processes, we summarize the currently characterized biological functions of DAZL in RNA biology and development. WIREs RNA 2014, 5:527–535. doi: 10.1002/wrna.1228This article is categorized under:

RNA Interactions with Proteins and Other Molecules > Protein–RNA Recognition
RNA Interactions with Proteins and Other Molecules > RNA–Protein Complexes
RNA Interactions with Proteins and Other Molecules > Protein–RNA Interactions: Functional Implications
Inter‐Tissue Differences in Fatty Acid Incorporation as a Result of Dietary Oil Manipulation in Port Jackson Sharks (Heterodontus portusjacksoni)
Authors: Beckmann Crystal L. , Mitchell James G. , Stone David A. J. , Huveneers Charlie 
Published: April 2014

AbstractFatty acid profile analysis is a tool for dietary investigation that may complement traditional stomach contents analysis. While recent studies have shown that the liver of sharks fed different diets have differing fatty acid profiles, the degree to which diet is reflected in shark blood serum and muscle tissue is still poorly understood. An 18‐week controlled feeding experiment was undertaken using captive Port Jackson sharks (Heterodontus portusjacksoni). Sharks were fed exclusive diets of artificial pellets treated with fish or poultry oil and sampled every 6 weeks. The fatty acid profiles from liver, blood serum, and muscle were affected differently, with the period from which significant differences were observed varying by tissue and diet type. The total fatty acid profiles of fish oil and poultry oil fed sharks were significantly different from week 12 onwards in the liver and blood serum, but significant differences were only observed by week 18 in the muscle tissue of sharks fed different diets. The drivers of dissimilarity which aligned with dietary input were 14:0, 18:2n‐6, 20:5n‐3, 18:1n‐9 and 22:6n‐3 in the liver and blood serum. Dietary fatty acids accumulated more consistently in the liver than in the blood plasma or muscle, likely due to its role as the central organ for fat processing and storage. Blood serum and muscle fatty acid profiles were influenced by diet, but fluctuated over‐time. The low level of correlation between diet and muscle FA profiles is likely a result of low levels of fat (<1 %) in the muscle and the domination of structural, cell‐membrane phospholipids in shark muscle tissues. Our findings describe inter‐tissue differences in the incorporation of fatty acids from the diet to consumer, which should be taken into account when interpreting dietary patterns from fatty acid profiles.
Plasma Lipids, Lipoprotein Metabolism and HDL Lipid Transfers are Equally Altered in Metabolic Syndrome and in Type 2 Diabetes
Authors: Silva Vanessa M. , Vinagre Carmen G. C. , Dallan Luis A. O. , Chacra Ana P. M. , Maranhão Raul C. 
Published: April 2014

AbstractMetabolic syndrome (MetS) refers to states of insulin resistance that predispose to development of cardiovascular disease and type 2 diabetes (T2DM). The aim was to investigate whether plasma lipids and lipid metabolism differ in MetS patients compared to those with T2DM with poor glycemic control (glycated hemoglobin > 7.0). Eighteen patients with T2DM, 18 with MetS and 14 controls, paired for age (40–70 years) and body mass index (BMI), were studied. Plasma lipids and the kinetics of a triacylglycerol‐rich emulsion labeled with [3H]‐triolein ([3H]‐TAG) and [14C]‐cholesteryl esters ([14C]‐CE) injected intravenously followed by one‐hour blood sampling were determined. Lipid transfers from an artificial nanoemulsion donor to high‐density lipoprotien (HDL) were assayed in vitro. Low‐density lipoprotein (LDL) and HDL cholesterol (mg/dl) were not different in T2DM (128 ± 7; 42 ± 7) and MetS (142 ± 6; 39 ± 3), but triacylglycerols were even higher in MetS (215 ± 13) than in T2DM (161 ±11, p < 0.05). Fractional clearance rate (FCR, in min1) of [3H]‐TAG and [14C]‐CE were equal in T2DM (0.008 ± 0.018; 0.005 ± 0.024) and MetS (0.010 ± 0.016; 0.006 ± 0.013), and both were reduced compared to controls. The transfer of non‐esterified cholesterol, phospholipids and triacylglycerols to HDL was higher in MetS and T2DM than in controls (p < 0.01). Cholesteryl ester transfer and HDL size were equal in all groups. Results imply that MetS is equal to poorly controlled T2DM concerning the disturbances of plasma lipid metabolism examined here, and suggest that there are different thresholds for the insulin action on glucose and lipids. These findings highlight the magnitude of the lipid disturbances in MetS, and may have implications in the prevention of cardiovascular diseases.
More Than One Million New American Indians in 2000: Who Are They?
Authors: Liebler Carolyn A. , Ortyl Timothy 
Published: April 2014

AbstractMore than one million people reported their race as American Indian/Alaska Native (AIAN) in the 2000 U.S. census but did not do so in the 1990 census. We ask three questions. First, which subgroups had the greatest numerical growth? Second, which subgroups had the greatest proportional increase? And third, are the 2000 single-race AIANs and the 1990 AIANs the same set of people? We use full-count and high-density decennial census data; adjust for birth, death, and immigration; decompose on age, gender, Latino origin, education, and birth state; and compare the observed subgroup sizes in 2000 with the sizes expected based on 1990 counts. The largest numerical increases were among adolescent and middle-aged non-Latinos, non-Latino women, and adults with no college degree. Latinos, women, highly educated adults, and people born in Eastern states had the largest proportionate gains. The ability to report multiple races in 2000 and the new federal definition of “American Indian” may have especially affected these groups, although personal-identity changes are probably also involved. We find that thousands of new Latino AIANs reported only one race in 2000, but many 1990 AIANs reported multiple races in 2000. Thus, the 1990 AIANs and 2000 single-race AIANs are not always the same individuals.
Exploring the Middle Classes in Nairobi: From Modes of Production to Modes of Sophistication
Authors: Spronk Rachel 
Published: April 2014

Abstract:This article explores the middle classes as cultural practice by focusing on the young professionals, or “yuppies,” of Nairobi. Young professionals are particularly interesting to study because they are the population that has reaped the benefits of a historical development of socioeconomic opportunities. They also occupy an interesting position in the context of local preoccupations with being modern or “sophisticated” in Kenya and in terms of the expectations and assumptions of previous generations. The article touches briefly on the history of class analysis in African studies and then, departing from Marx and following a Weberian analysis, shows how three factors are important in analyzing the middle classes and the forging of class identities in a globalizing world: access to education, resulting in salaried occupations; consumption patterns; and modern self-perceptions.
SPIRITUAL BORDER CROSSINGS: CHILDBIRTH, POSTPARTUM SECLUSION AND RELIGIOUS ALTERITY IN AMHARA, ETHIOPIA
Authors: Hannig Anita 
Published: April 2014

ABSTRACTThis article examines the event of postpartum seclusion of mother and infant in the Amhara region of north-west Ethiopia. During the period between birth and baptism, the mother–child pair remains in private repose, is subject to a variety of ritual prohibitions, and is barred from entering a church. Despite the mother's Orthodox Christian identity, both she and the child are called ‘Muslims’ during this time. Why should this be the case? What happens during the birthing event and its aftermath that would bring about this temporary shift in their religious designation? By shedding light on the distinct models of maternal care, safety, and danger that are emphasized in ‘childbed’, this study seeks an answer to these questions. In doing so, it also contributes to a broader understanding of why most Amhara mothers do not, at present, avail themselves of institutional deliveries and biomedical births but prefer to give birth at home.