bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular dynamics simulations on dextran hydrogels
Authors: Chen Jun , Zhou Si-Min , Ma Bao-Guang , Zhang Li-Ming , Yi Ju-Zhen
Published: May 2014

To probe the detailed structure of dextran hydrogels, periodical models for three dextran hydrogel systems with different dextran contents have been constructed and compared using molecular dynamic simulations. The software packages of Amorphous and Discover in Material Studio with COMPASS force field were used for the simulation. Energy minimization and geometry optimization were used to refine the models. In particular, the structure and dynamic movement of dextran chains which impose on water in the dextran hydrogel systems have been studied. The results show that in the physically crosslinked dextran hydrogels, KCl served as the crosslinker and it interacted with dextran via the oxygen atoms of hydroxyl groups in dextran ring. With increasing dextran content, the free volumes of the hydrogels and the diffusion coefficients of water in the hydrogel decrease. By the radial distribution analysis, the water in the hydrogel networks was found to interact with dextran via hydrogen bond and there are at least three kinds of water in the physically crosslinked dextran hydrogels. These results have a great significance for understanding the structure and properties of the hydrogel.
Evaluation of poly(methyl methacrylate) latex nanoparticles used in water-based drilling fluids
Authors: Bai Xiaodong , Wang Xu , Pu Xiaolin
Published: May 2014

In the prospecting and drilling processes of gas and oil, if added into the drilling fluids, the latex nanoparticles can improve the performance of the drilling fluids. In this paper, methyl methacrylate (MMA) acts as a monomer and the combination emulsifier is a certain proportion of OP-10, RH and T-80. PMMA latex nanoparticles have been polymerized through the method called microemulsion polymerization. The conditions of methyl methacrylate microemulsion polymerization have been discussed and optimized. The dosage of emulsifier is 5 wt.%, polymerization temperature is 75 0C, and the stirring rate is 100 rpm. The particle shape, granularity distribution and molecular weight have been characterized by transmission electron microscope, laser particle size analysis device and gel permeation chromatography, respectively. The results indicate that the PMMA particles are ball like, showing average particle size of 65 nm, and that the MW is about 437,140. Results show that PMMA latex has strong inhibitive function on the shale swelling. When the latex is added into the drilling fluids, the filter loss decreases dramatically; and the PMMA latex drilling fluids system can be used when the temperature is below 180 0C.
Application of high-resolution transmission electron microscopy and electron energy-loss spectroscopy in the characterization of polymer nanotubes
Authors: Shang Lei , Li Xiaoru , Wang Yiqian
Published: May 2014

Polyamide 6 (PA6) and polystyrene (PS) nanotubes were successfully fabricated by polymer solution-wetting method. High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and electron energy-loss spectroscopy (EELS) techniques were employed to investigate their crystallization phenomena. It has been found in HRTEM images that the crystalline lattice fringes are observed in some regions of the nanotube walls. XRD analysis showed that these two kinds of polymer nanotubes have a higher degree of crystallinity than that of the bulk materials. PA6 nanotubes dominate in γ phase while bulk PA6 present mainly in α phase. EELS has been used to determine the ratio of C=C and C-C in PS nanotubes, and our result is consistent with the theoretical calculation. HRTEM and EELS will shed light on the microstructural characterization of polymer nanotubes.
Synthesis of binary-patterned brushes by combining atom transfer radical polymerization and ring-opening polymerization
Authors: Olivier Aurore , Meyer Franck , Raquez Jean-Marie , Dubois Philippe
Published: May 2014

This paper report the synthesis of binary-patterned brushes, combining two distinctive surface initiated-polymerizations (SIP) on the basis of different propagating species: the SI Ring Opening Polymerization (ROP) of L-Lactide (LLA) and SI atom transfer radical polymerization (ATRP) of N,N’-dimethylaminoethyl methacrylate (DMAEMA) on gold surface. First of all, a careful study of surfaceinitiated ROP of L-Lactide from hydroxyl end-group of thiol monolayer on gold surface as catalyzed by metal-free catalyst was carried out. The PLLA brushes synthesis was evaluated using two types of thiol monolayer and revealed the influence of ROP initiator chain length on the final thickness of the PLLA film. Combining the soft lithographic technique, microcontact printing, and the liquid phase deposition, the deposition onto specific micro-domains of both initiators was performed. The growth of PDMAEMA brushes and PLLA brushes was conducted by successive ATRP and ROP.
Effect of the boron presence on the properties of polyurethane foams obtained with hydroxypropyl derivatives of oxamide as the polyol components
Authors: Zarzyka Iwona
Published: May 2014

The results of esterification of N,N'-bis(2-hydroxypropyl)oxamide (BHPOD) with the use of boric acid (BA) have been described. Subsequently hydroxypropyl derivatives of oxamide (OD) modified with boron as products of the reaction of BHPOD esterified boric acid with an excess of propylene carbonate (PC) have been obtained. Foamed polyurethane materials received with the use of these derivatives as polyol components and diisocyanate 4,4'-diphenylmethane exhibited higher thermal stability and compressive strength compared to the foams obtained with hydroxypropyl derivatives of OD which do not contain boron.
Preparation of poly(vinyl alcohol)/silica nanocomposties by sol-gel method
Authors: Zhao Yan-Na
Published: May 2014

The poly(vinyl alcohol)/silica nano-composities hybrid membranes were prepared by co-hydrolysis and co-condensation of γ-glycidyloxypropyl trimethoxysilane (GPTMS) and tetraethoxysilane (TEOS) in poly(vinyl alcohol)(PVA) aqueous solution. The mechanical properties of hybrid membranes was studied, the result indicated that the well dispersion of nanoparticles was beneficial to the enhancement of the mechanical properties, and GPTMS could increase the miscibility of the polymer and SiO2. The membranes were characterized by scanning eletron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDS), 29Si CP/MAS solid-state nuclear magnatic resonance (NMR). The EDS of poly(vinyl alcohol)/silica nano-composities showed that Si element had been grafted onto the chain of PVA. The 29Si CP/MAS solidstate NMR spectra, 13C CP/MAS Solid-state NMR spectrum and EDS confirmed that silica had been introduced into the chain of PVA. Latex particle size and morphology was observed by transmission electron microscopy (TEM) and dynamic light scattering (DLS). The TEM and DLS indicated that silica nanoparticles well and regularly dispersed in PVA solution and the average diameter of silica nanoparticles dispersed in PVA solution was about 58 nm.
Synthesis and characterization of novel polysiloxane based ABA-type triblock copolymers using ATRP
Authors: Bodkhe Rajan B. , Webster Dean C.
Published: May 2014

Novel polysiloxane based ABA-type triblock copolymers having a secondary amine at the junction point were synthesized using a combination of ring opening equilibration polymerization (ROEP), Michael addition and atom transfer radical polymerization (ATRP). Polysiloxane based bifunctional ATRP macroinitiators were synthesized and subsequently used for controlled radical polymerization of t-butyl acrylate (t-BA) and sulfobetaine methacrylate (SBMA). Gel permeation chromatography (GPC) analysis of the triblocks based on t-BA showed high chain end functionality, due to the disappearance of peaks related to the macroinitiator. ROEP can be used to control the block length of the polysiloxane while ATRP can be used to control the chain length of the outer blocks, making the ABA- type triblock a unique material with secondary amine functionality which can be used for further reaction.
Tuning of heavy metal removal efficiency from water via micro algae/hydrogel composites
Authors: Aydınoğlu Demet , Şen Sinan , Helvacıoğlu Ekmel , Nugay Turgut , Nugay Nihan
Published: May 2014

A series of micro algea-based hydrogel composites were prepared from polyacrylamide and Spirulina (PAAm-sp). Free radical polymerization of acrylamide (AAm) in the presence of N,N-methylene bis-acrylamide (BAAm), as a crosslinker, and Spirulina microalgae in different loadings was conducted. Chromium metal adsorption capacity was determined with UV-VIS spectroscopy whereas mechanical performance of the resultant hydrogel composites was followed with uniaxial compression experiments. It has been found that efficiency can be tuned by Spiriluna composition in hydrogel. PAAm hydrogel composite having 0.5 % Spirulina had the maximum compression strength, good swelling in water as well as improved thermal stability due to the special and beneficial ‘fishnet morphology” observed via scanning electron microscopy (SEM). The observed high performance of this composition is proved to be due to this morphology where all potential binding sites are under receptive position for metal adsorption. Spirulina by itself in water can remove only about 2 % of its weight of Cr+3 ion, however in the hydrogel structure this removal increases up to 200 % which makes this biotechnological approach superior in the metal removal from the water.
Enantioselective analysis of naproxen using chiral molecular imprinting polymers based thin-layer chromatography
Authors: Huangfu Fengyun , Wang Bing , Shan Juanjuan , Zhang Zhiliang
Published: May 2014

This paper describes a rational design and testing of molecularly imprinted polymers (MIPs) as chiral stationary phases of thin-layer chromatography (TLC) for enantiomeric purity of naproxen. Using D-naproxen as template, MIPs with particle size between 10~90 μm were prepared by precipitation polymerization in acetonitrile/methanol mixed solvent. The interactions between functional monomers and template were verified by UV absorption spectrometry. The morphology, particle size distribution and specific surface area of MIPs were also observed by scanning electron microscopy, particle size distribution meter and liquid nitrogen adsorption instrument, respectively. Binding capacities of MIPs had been studied by equilibrium binding assay. Preparation conditions of TLC and impact of acetic acid content on the separation of enantiomers were investigated. The results indicated that when acetic acid content was 4%, the racemates of templates were completely separated, and the chiral separation factor α was 1.58.
Controlled release of Capreomycin sulfate from pHresponsive nanocapsules
Authors: Loiko Olessya P. , Herk Alex M. van , Ali Syed I. , Burkeev Meiram Zh. , Tazhbayev Yerkeblan M. , Zhaparova Lyazzat Zh.
Published: May 2014

The synthesis of polymeric nanocapsules loaded with the antituberculosis drug Capreomycin sulphate is presented in this work. The pHresponsive polymeric nanocapsules were successfully synthesized using the RAFT-based vesicle templating approach in the presence of Capreomycin sulphate. Anionic small polyelectrolytes comprising randomly distributed butyl acrylate and acrylic acid units were adsorbed on cationic vesicles of dimethyldioctadecyl ammonium bromide (DODAB). N,N-(dimethylamino)ethyl methacrylate (DMAEMA) and methyl methacrylate (MMA) or tertiary butyl methacrylate (tBMA) and MMA were used for the formation of the polymeric shells. Subsequently the tBMA was hydrolyzed to obtain negatively charged nanocapsules. The nanocapsule morphology for both approaches was characterized by DLS and TEM. The most stable hollow latex particles were obtained with the monomer composition of DMAEMA:MMA = 1:1. These nanocapsules were found to be colloidally stable and pH-responsive. The entrapment efficiency of drug determined by UV-Vis-spectroscopy was 70 %. The drug release rate from nanocapsules at pH 6.5 was found to be relatively fast (substantial release within one hour already), however we believe slower release can be achieved by using a thicker polymer shell.
Rheological measurement of molecular weight distribution of polymers
Authors: Khak Maryam , Ramazani Ahmad S. A.
Published: May 2014

This paper has described a method to obtain the molecular weight distribution (MWD) of polymeric materials from their rheological data. The method has been developed for linear polymers with log normal molecular weight distribution. The rheological data required to obtain the molecular weight distribution are the shear storage modulus,G' (ω) , and shear loss modulus,G" (ω) , extending from the terminal zone to the plateau region. For determining the molecular weight average, the method uses the relationship between stress moduli and relaxation spectrums, with the equation that connects dynamic rheological data with molecular weight distribution, and so it is not necessary to achieve the relaxation spectrums and the molecular weight distribution is obtained directly from dynamic shear experiments and it is one of the main advantageous of the proposed method. Comparison of calculated and experimental data obtained by GPC for five polypropylene samples produced in different conditions show that model can correctly predict molecular weight distribution for these types of polymers.
Chain length distribution and kinetic characteristics of an enzymatically produced polymer
Authors: Mulders K.J.M. , Beeftink H.H.
Published: May 2014

Non-processive enzymatic polymerization leads to a distribution of polymer chain lengths. A polymerization model was developed to investigate the relation between the extent of this distribution on one hand, and the polymerization start conditions and reaction kinetics on the other hand. The model describes changes in concentration of chains of length n as the result of two elongation reactions: elongation by monomer addition to length n-1 and elongation by monomer addition to length n. Polymerization reactions were assumed to be zero order in monomer concentration and to obey Michaelis-Menten kinetics with respect to polymer concentrations. In addition, the amount of enzyme available for each individual reaction (n → n+1) is assumed to be proportional to the concentration of polymer substrate of length n. The development of the shape of the chain length distribution was found to be independent of the value of the overall reaction rate constant; only the rate at which these shapes developed was influenced by the 1st-order rate constant. The value of the Michaelis parameter did affect the form of the chain length distribution curve since it affects the reaction order. An increase in reaction order was found to promote widening of the chain length distribution. Differences in kinetic parameters between the subsequent polymerization reactions, if any, were also found to have a large effect on the development of the chain length distribution. An increase in rate constants with chain length entailed a wider distribution; a more narrow distribution would require a decrease in rate constants with chain length.
Hydrogen effects in the polymerization of propylene with C2 symmetric metallocene catalysts
Authors: Amer Ismael , Reenen Albert van
Published: May 2014

Propylene was polymerized with two C2 symmetric metallocene catalysts, ethylene bis(indenyl)zirconium dichloride and dimethylsilyl bis(2-methylbenz( e) indenyl) zirconium dichloride, in the presence of increasing amounts of hydrogen. The hydrogen influenced the molecular weight significantly, as was expected. The degree of isotacticity of the polypropylene was influenced by the level of hydrogen added during polymerization, and the amount and type of stereoerrors as determined by 13C NMR increased as hydrogen levels were increased. Results indicated that efficiency of enantiomorphic site control is dependent on the length of the growing polymer chain during polymerization.
Encapsulation of human serum albumin in submicrometer magnetic poly(lactide-co-glycolide) particles as a model system for targeted drug delivery
Authors: Shubhra Quazi T.H. , Macková Hana , Horák Daniel , Fodor-Kardos Andrea , Tóth Judit , Gyenis János , Feczkó Tivadar
Published: May 2014

Two types of iron oxide nanoparticles were synthesized by coprecipitation of Fe(II) and Fe(III) chlorides: water-dispersible γ-Fe2O3 and organic solvent-dispersible oleic acid-coated Fe3O4 particles. The nanoparticles, together with human serum albumin (HSA) serving as a model for a protein-type drug, were then incorporated in poly(lactide-co-glycolide) (PLGA) particles using double emulsion solvent evaporation technique. Morphology, size and particle size distribution of the resulting particles was analyzed by electron microscopy and dynamic light scattering. Iron oxide and HSA encapsulating efficiency was determined by Prussian Blue staining and micro-BCA assay, respectively.
Patriarchy and New Comedy in Ancient Athens and Rome: Revisiting Northrop Frye's “Mythos of Spring: Comedy”
Authors: Caron James E.
Published: May 2014

Few theoretical statements about comic drama and fiction can match the influence of Northrop Frye's essay, “Mythos of Spring: Comedy.” Particularly for scholars interested not only in classic comic literary forms such as stage comedy, but also in the popular forms of contemporary films as well as television sitcoms, Frye's theory continues to be useful for understanding basic structures within large quantities of examples. In this essay, I challenge Frye's model for comic art. Although a quasi-Oedipal plot dominates extant New Comedy, the model suppresses the fact that it is only one significant plot among others capable of generating variations. More importantly, when one examines plays structured by the quasi-Oedipal plot, Frye's summary – a generational struggle that ends in the son's triumph – misrepresents the material: the son's triumph is not a foregone conclusion. New Comedy's function as the symbolic womb of the Western comic tradition is thus far from unproblematic. My challenge has serious consequences, not just for those critics who have organized their analyses on it, but also for those critics who might theorize about literary and popular art forms, as well as for scholars who would write a history of comic forms in the West.
Kynical dogs and cynical masters: Contemporary satire, politics and truth-telling
Authors: Higgie Rebecca
Published: May 2014

This article proposes that the philosophical techniques found in contemporary satires can be understood using a spectrum that ranges between the cynical and the kynical. Cynicism is the belief that there is no hope for change, that truth is dead, while kynicism – a non-nihilistic form of cynicism – maintains that truth does exist, and is worth saving from political and media manipulations. By exploring the evolution of kynicism, from its origins in ancient Greek philosophy to its presence in contemporary satire, I analyze how
Hoisan-wa in jest: Humor, laughter, and the construction of counter-hegemonic affect in contemporary Chinese American language maintenance
Authors: Leung Genevieve
Published: May 2014

This research examines the language and cultural maintenance of Chinese Americans of a specific heritage:

Drawing from 93 sociolinguistic interviews with
Inter- and intra-observer variability in cervical measurement by ultrasound in the first and second trimesters of pregnancy: does it matter?
Authors: França Cíntia , Carraca Teresa , Monteiro Sofia Bessa , Rodrigues Teresa , Montenegro Nuno , Severo Milton , Matias Alexandra
Published: May 2014

Objectives: The aim of this study was to evaluate the inter- and intra-observer variabilities in the cervical length (CL) measurement by transvaginal ultrasound (TVU) in the first and second trimesters of pregnancy.

Materials and methods: A total of 55 singleton pregnant women were evaluated in the first or second ultrasound. Each patient was blindly evaluated by three of the four observers who performed three measurements each.

Results: In the first and second trimesters, patients were evaluated at 12.3 weeks (mean) and 21.3 weeks (mean), respectively. The intra-class correlation coefficients (ICC) between observers in the first and second trimesters were 0.76 and 0.72, respectively, and the ICCs within observers were 0.889 and 0.899, respectively. In both trimesters, the main source of variance was the patient and the second source of variance was the interaction, Patient×Observer (12.0% and 13.5%, respectively). The observer and measurement explained a small proportion of variance in both trimesters (1.4% and 0.4%, respectively in the 1st trimester, and 3.3% and 0%, respectively in the 2nd trimester). The residual variances were 10.6% and 11.2%, and the standard errors of measurement were 1.78 mm and 1.82 mm for the first and second trimesters, respectively.

Conclusions: TVU is a reliable and reproducible method by which to predict preterm birth in both the first and second trimesters.
Crystal structure of 3-ethyl-1,5-dioxaspiro[5,5]undecane-3-carboxylic acid, C12H20O4
Authors: Yuan Lin , Jia Guo-Kai , Zhang Min , Yuan Xian-You
Published: May 2014

C
Crystal structure of (,2-2,2'-bipyrimidine-κ4N1,N1':N3,N3')bis[iodido (t-butyldiphenylphosphane-κP)copper(I)]dimethylformamide disolvate, C40H44Cu2I2N4P2·2(C3H7NO), C46H58Cu2I2N6O2P2
Authors: Fettouhi Mohammed
Published: May 2014

C
Crystal structure of 2-(methylthio)thiazolo[4,5-c]pyridine, C7H6N2S2
Authors: Tian Xin-Zhe , Zhao Shuang , Wang Wei-Min , Jin Chao-Xi
Published: May 2014

C
Effect of the quenching temperature on the mechanical and thermophysical properties of polycarbonate pigmented with titanium dioxide
Authors: Rouabah Farid , Dadache Derradji , Fois Magali , Haddaoui Nacceredine
Published: May 2014

This work deals with the effect of the quenching temperature on the mechanical and thermophysical properties of polycarbonate (PC) pigmented with titanium dioxide (TiO2). The thermal conductivity, thermal diffusivity, Izod impact strength and density measurements were measured. The thermal conductivity and diffusivity of the composites were measured using a periodic measurement method. It was found that an additional second quenching involved an increase in the value of the Izod impact strength near 35°C and a decrease in the values of the density, the thermal conductivity and the thermal diffusivity. A transition in these properties which is located at around 35°C has also been observed and linked to the β1 relaxation mode of PC.
Preparation and characterization of oxidized starch-graft-poly(styrene-butyl acrylate) latex via emulsion polymerization
Authors: Cheng Shijie , Xu Jun , Wu Yumin
Published: May 2014

Oxidized starch-graft-poly(styrene-butyl acrylate) [OS-g-P(St-BA)] latex was synthesized by the graft copolymerization of OS with St and n-butyl acrylate (BA) via emulsion polymerization. The graft copolymers were characterized by Fourier transform infrared (FT-IR), transmission electronic microscopy (TEM), dynamic light scattering, thermogravimetry (TG), and differential scanning calorimetry (DSC). The effects of the amount of OS, monomers, and initiator on graft copolymerization were investigated. Under the optimal conditions, the percentage of graft (PG), grafting efficiency (GE), and ζ potential could reach 256.5%, 41.7%, and -30.1 mV, respectively. The results indicated that the OS grafted onto particles greatly enhanced the colloidal stability of latex. The thermal stability properties of OS-g-P(St-BA) were also improved by the addition of OS. The OS-g-P(St-BA) latex may be used to partly replace the conventional synthetic latex for paper coating.
Cationic copolymerization of 1,3-pentadiene with α-pinene
Authors: Li Ai-Yuan , Sun Xiang-Dong , Zhang Hui-Bo , Zhang Yong-Chun , Wang Bin , Shi Li-Qin
Published: May 2014

The cationic copolymerization of 1,3-pentadiene (PD) with α-pinene (AP) initiated by aluminum trichloride (AlCl3) was carried out in N-pentane solvent. The effects of the polymerization temperature and the comonomer composition on the yield of the copolymer, softening point, Gardner color scale and number-average molecular weight (Mn) are discussed. The performance of the copolymer was better than that of AP homopolymer (PAP) and PD homopolymer (PPD). The structure of the copolymer was characterized by Fourier transform infrared spectroscopy (FT-IR), 1H-nuclear magnetic resonance (1H-NMR), 13C-NMR, differential scanning calorimetry (DSC) and gel permeation chromatography (GPC). In addition, the reactivity ratios for AP (M1) and PD (M2) determined by the Kelen-Tudos method from low-conversion data are r1=0.58 and r2=5.92, respectively.
X-ray absorption spectroscopy investigations on radioactive matter using MARS beamline at SOLEIL synchrotron
Authors: LLorens Isabelle , Solari Pier Lorenzo , Sitaud Bruno , Bes René , Cammelli Sebastiano , Hermange Hervé , Othmane Guillaume , Safi Sami , Moisy Philippe , Wahu Sandrine , Bresson Carole , Schlegel Michel L. , Menut Denis , Bechade Jean-Luc , Martin Philippe , Hazemann Jean-Louis , Proux Olivier , Den Auwer Christophe
Published: May 2014

The MARS beamline at the SOLEIL synchrotron is dedicated to the characterization of radioactive material samples. One great advantage of the beamline is the possibility to characterize about 380 radionuclides by different X-ray techniques in the same place. This facility is unique in Europe. A wide energy range from around 3.5 keV to 36 keV K-edges from K to Cs, and L3 edges from Cd to Am and beyond can be used. The MARS beamline is optimized for X-ray absorption spectroscopy techniques (XANES/EXAFS), powder diffraction (XRD) but x-ray fluorescence (XRF) analysis, High Energy Resolution Fluorescence Detected -XAS (HERFD-XAS), X-ray Emission (XES) and μ-XAS/XRD are also possible. A description of the beamline as well as its performances are given in a first part. Then some scientific examples of XAS studies from users are presented which cover a wide variety of topics in radiochemistry and nuclear materials.
Identification of a gene regulatory network associated with prion replication
Authors: Marbiah Masue M , Harvey Anna , West Billy T , Louzolo Anais , Banerjee Priya , Alden Jack , Grigoriadis Anita , Hummerich Holger , Kan Ho‐Man , Cai Ying , Bloom George S , Jat Parmjit , Collinge John , Klöhn Peter‐Christian
Published: May 2014

Prions consist of aggregates of abnormal conformers of the cellular prion protein (PrPC). They propagate by recruiting host‐encoded PrPC although the critical interacting proteins and the reasons for the differences in susceptibility of distinct cell lines and populations are unknown. We derived a lineage of cell lines with markedly differing susceptibilities, unexplained by PrPC expression differences, to identify such factors. Transcriptome analysis of prion‐resistant revertants, isolated from highly susceptible cells, revealed a gene expression signature associated with susceptibility and modulated by differentiation. Several of these genes encode proteins with a role in extracellular matrix (ECM) remodelling, a compartment in which disease‐related PrP is deposited. Silencing nine of these genes significantly increased susceptibility. Silencing of Papss2 led to undersulphated heparan sulphate and increased PrPC deposition at the ECM, concomitantly with increased prion propagation. Moreover, inhibition of fibronectin 1 binding to integrin α8 by RGD peptide inhibited metalloproteinases (MMP)‐2/9 whilst increasing prion propagation. In summary, we have identified a gene regulatory network associated with prion propagation at the ECM and governed by the cellular differentiation state.
Lower serum osteocalcin is associated with more severe metabolic syndrome in elderly men from the MINOS cohort
Authors: Confavreux Cyrille B , Szulc Pawel , Casey Romain , Varennes Annie , Goudable Joelle , Chapurlat Roland D
Published: May 2014

Background

Bone has emerged as an endocrine organ regulating energy metabolism through secretion of osteocalcin. In epidemiological studies, presence of metabolic syndrome (MetS) was associated with lower osteocalcin level.

Objectives

We evaluated whether osteocalcin level was associated with MetS severity in men and whether it was more strongly associated with MetS compared with N-terminal propeptide of type I procollagen (PINP), bone-specific alkaline phosphatase (BAP), and C-terminal telopeptide of type I collagen (βCTX).

Methods

We included 798 men aged 51–85 years for total osteocalcin measurement. Number of MetS criteria was used to define severity. We used polytomous logistic regression to assess the relationship between MetS severity and osteocalcin level.

Results

Thirty percent of men had MetS. In patients with MetS, the higher the number of MetS traits were present, the lower was the average osteocalcin level (0–2 criteria: 551 men: 19.5±6.7 ng/ml, three criteria: 155 men: 19.3±7.4 ng/ml, four criteria: 72 men: 17.3±5.7 ng/ml, and five criteria: 20 men: 15.0±5.1 ng/ml;Pfor trend=0.002).

In the polytomous logistic regression model, an increase in osteocalcin level of 10 ng/ml was associated with lower prevalence of severe MetS: three criteria (odds ratio (OR)=0.93 (0.70–1.24)), four criteria (OR=0.54 (0.34–0.84)), and five criteria (OR=0.28 (0.10–0.82)) in comparison with no MetS (Pfor trend=0.008).

After adjustment, using stepwise analysis of the polytomous logistic regression model, we observed that osteocalcin, age, and apparent free testosterone entered in the model but not other bone markers (PINP, βCTX, and BAP).

Conclusion

In older Caucasian men, total osteocalcin level was associated with MetS severity. Osteocalcin was more strongly associated with MetS severity than other bone turnover markers.
Comparison of universal and targeted screening for thyroid dysfunction in pregnant Egyptian women
Authors: Ahmed Iman Z , Eid Yara M , El Orabi Hussein , Ibrahim Hani Refat
Published: May 2014

Objective

To compare universal vs targeted screening for thyroid dysfunction and to estimate the prevalence of hypothyroidism in pregnant Egyptian women.

Subjects and methods

A total of 168 of pregnant women who attended the outpatient obstetric clinic at Ain Shams University Hospital (Cairo, Egypt) for antenatal care between September 2011 and December 2011 were enrolled. Based on the detailed data collection and results of laboratory testing, they were subdivided into the high- and low-risk group for thyroid disease according to the most recent Endocrine Society clinical practice guidelines, as well as into groups by trimester for application of American Thyroid Association guidelines. The group values were subjected to statistical analysis for estimating the prevalence of clinical and subclinical hypothyroidism and for identifying significant differences.

Results

Of the 168 patients, 104 were classified into the low-risk group and 64 into the high-risk group. Using the trimesteric and normal population cutoff values for thyroid functions, the prevalence of hypothyroidism was found to be 56% (n=94) and 44.6% (n=75) respectively. No statistically significant differences were found between the high- and low-risk group regarding prevalence of either clinical or subclinical hypothyroidism, and no significant differences were found regarding the prevalence of hypothyroidism in the first, second, or third trimester.

Conclusion

Use of the most recent Endocrine Society clinical practice guidelines led to missed detection of clinical or subclinical hypothyroidism in 34.5% of pregnant women. Universal screening of pregnant women for thyroid dysfunction should thus be adopted throughout Egypt.
The neonatal marmoset monkey ovary is very primitive exhibiting many oogonia
Authors: Fereydouni B , Drummer C , Aeckerle N , Schlatt S , Behr R
Published: May 2014

Oogonia are characterized by diploidy and mitotic proliferation. Human and mouse oogonia express several factors such as OCT4, which are characteristic of pluripotent cells. In human, almost all oogonia enter meiosis between weeks 9 and 22 of prenatal development or undergo mitotic arrest and subsequent elimination from the ovary. As a consequence, neonatal human ovaries generally lack oogonia. The same was found in neonatal ovaries of the rhesus monkey, a representative of the old world monkeys (Catarrhini). By contrast, proliferating oogonia were found in adult prosimians (now called Strepsirrhini), which is a group of ‘lower’ primates. The common marmoset monkey (Callithrix jacchus) belongs to the new world monkeys (Platyrrhini) and is increasingly used in reproductive biology and stem cell research. However, ovarian development in the marmoset monkey has not been widely investigated. Herein, we show that the neonatal marmoset ovary has an extremely immature histological appearance compared with the human ovary. It contains numerous oogonia expressing the pluripotency factors OCT4A, SALL4, and LIN28A (LIN28). The pluripotency factor-positive germ cells also express the proliferation marker MKI67 (Ki-67), which has previously been shown in the human ovary to be restricted to premeiotic germ cells. Together, the data demonstrate the primitiveness of the neonatal marmoset ovary compared with human. This study may introduce the marmoset monkey as a non-human primate model to experimentally study the aspects of primate primitive gonad development, follicle assembly, and germ cell biologyin vivo.
Infinium Monkeys: Infinium 450K Array for the Cynomolgus macaque (Macaca fascicularis)
Authors: Ong Mei-Lyn , Tan Peck Yean , MacIsaac Julia L , Mah Sarah M , Buschdorf Jan Paul , Cheong Clara Y , Stunkel Walter , Chan Louiza , Gluckman Peter D , Chng Keefe , Kobor Michael S , Meaney Michael J , Holbrook Joanna D
Published: May 2014

The Infinium Human Methylation450 BeadChip Array (Infinium 450K) is a robust and cost-efficient survey of genome-wide DNA methylation patterns. Macaca fascicularis (Cynomolgus macaque) is an important disease model; however, its genome sequence is only recently published, and few tools exist to interrogate the molecular state of Cynomolgus macaque tissues. Although the Infinium 450K is a hybridization array designed to the human genome, the relative conservation between the macaque and human genomes makes its use in macaques feasible. Here, we used the Infinium 450K array to assay DNA methylation in 11 macaque muscle biopsies. We showed that probe hybridization efficiency was related to the degree of sequence identity between the human probes and the macaque genome sequence. Approximately 61% of the Human Infinium 450K probes could be reliably mapped to the Cynomolgus macaque genome and contain a CpG site of interest. We also compared the Infinium 450K data to reduced representation bisulfite sequencing data generated on the same samples and found a high level of concordance between the two independent methodologies, which can be further improved by filtering for probe sequence identity and mismatch location. We conclude that the Infinium 450K array can be used to measure the DNA methylome of Cynomolgus macaque tissues using the provided filters. We also provide a pipeline for validation of the array in other species using a simple BLAST-based sequence identify filter.
Genetic Control of Heterochrony in Eucalyptus globulus
Authors: Hudson Corey J , Freeman Jules S , Jones Rebecca C , Potts Brad M , Wong Melissa M L , Weller James L , Hecht Valérie F G , Poethig R Scott , Vaillancourt René E
Published: May 2014

A change in the timing or rate of developmental events throughout ontogeny is referred to as heterochrony, and it is a major evolutionary process in plants and animals. We investigated the genetic basis for natural variation in the timing of vegetative phase change in the tree Eucalyptus globulus, which undergoes a dramatic change in vegetative morphology during the juvenile-to-adult transition. Quantitative trait loci analysis in an outcross F2 family derived from crosses between individuals from a coastal population of E. globulus with precocious vegetative phase change and individuals from populations in which vegetative phase change occurs several years later implicated the microRNA EglMIR156.5 as a potential contributor to this heterochronic difference. Additional evidence for the involvement of EglMIR156.5 was provided by its differential expression in trees with early and late phase change. Our findings suggest that changes in the expression of miR156 underlie natural variation in vegetative phase change in E. globulus, and may also explain interspecific differences in the timing of this developmental transition.
Reflections of a food studies researcher: Connecting the community-university-policy divide….becoming the hyphens!
Authors: Frank Lesley
Published: May 2014

This narrative presents refections on the role of the food studies researcher from the prespective of a new academic with a background in community and policy work. It details a multi-phased, mixed methods case study on the public policy relations of infant food insecurity in Canada and provides a discussion of some unintentional outcomes of doing food studies research. The author suggests that an integrative approach, one where the researcher bridges the micro-effects of public policy with policy making realms, is ideally suited to food studies and food policy analysis. The narrative reveals how a researcher can become the hyphens in the community—university—policy divide through the process of storytelling.
Against the Odds: The Survival of Traditional Food Knowledge in a Rural Alberta Community
Authors: Braun Jennifer , Beckie Mary
Published: May 2014

The globalization and industrialization of the agri-food system has been linked to declining knowledge and skills in the general population related to growing, preserving and cooking food. In rural communities, loss of this knowledge and associated culture and traditions has been further exacerbated by depopulation due to outmigration and the subsequent erosion of social and physical infrastructure. Counter to this trend of food deskilling, however, are the efforts of individuals who are actively working to maintain and perpetuate traditional food practices. The purpose of this research was to understand what factors motivate and enable the preservation of gardening, cooking and canning skills among a group of women and their children in a small rural community in Alberta. Qualitative research methods were used to gather relevant data, which were analyzed using a social practice theoretical lens. Findings from this study revealed four conditions influencing the continuation of these social practices among the research participants: the experience and history of scarcity; normative expectations; a close connection to family; and, development of a community of practice. This study illustrates the relevance of a social practice framework for examining food knowledge and skills, and points to the potential of this approach for understanding and promoting pro-environmental behaviour and sustainable consumption in the food system.
Do trade agreements substantially limit development of local / sustainable food systems in Canada?
Authors: MacRae Rod
Published: May 2014

A common view in policy and business circles is that certain elements of trade agreements (General Agreement on Tariff and Trade rules, the World Trade Organization Agreement on Agriculture, and the North American Free Trade Agreement) and the Canadian Agreement on Internal Trade significantly limit the policy and program instruments available to support the development of local/sustainable food systems.  This exploratory textual analysis of select trade articles, filtered through a local/sustainable lens, suggests that Canadian governments can put in place more substantial policy and program drivers without triggering trade disputes.  Of particular note is that local/sustainable foods may not be considered equivalent to imported conventional ones, and therefore many provisions of the trade agreements may not be applicable.  Equally important, the rules do permit certain kinds of support, there are numerous exemptions and thresholds for application of measures, and many current actors in local/sustainable implementation may not be subject to the agreements. Based on this textual analysis, pertinent instrument design features are proposed that would allow governments and other parties to support local/sustainable food systems without triggering trade disputes.
Benefit-sharing as a tool of conflict transformation: Applying the Inter-SEDE model to the Euphrates and Tigris river basins
Authors: Daoudy Marwa
Published: May 2014

The concept of benefit-sharing, as employed in the Inter-SEDE model, analyzes potential security, economic development, and environmental-related benefits to sharing the waters of the Euphrates and Tigris river basins. The article finds that Iraq scores fairly high on security and economics-related indicators, revealing the country's vulnerable downstream position. Syria's security score highlights this actor's vulnerable position as the mid-stream riparian. Turkey is favorably differentiated on some of the economic indicators. To enhance the potential for spill-over between watercooperation and conflict prevention, durable and peaceful relations among riparian states require that water-related benefits be shared.
Water, mining, and waste: An historical and economic perspective on conflict management in South Africa
Authors: Adler Rebecca A. , Claassen Marius , Godfrey Linda , Turton Anthony R.
Published: May 2014

Lack of government intervention in South Africa's mining industry has worsened conflicts associated with limited water resources. With the advent of democracy, new legislation demands that all South African citizens have the right to a clean, safe environment, including access to potable water, and that the country develop in a sustainable manner. But conflict remains due to the historical partnership between the government and the mining industry, as well as due to cumulative impacts associated with mining, which has polluted natural ground water sources. In this article, an historical overview of the mining industry in South Africa is presented, along with a simple economic model to describe behavior of the mining industry over time. Legislative frameworks used to address mine waste and mine water management are evaluated and suggestions are made for how to use an understanding of resource driven conflict to improve the outlook of mining and access to water for all in South Africa.
Water stress and water wars
Authors: Pryor Frederic L.
Published: May 2014

This essay argues three propositions: (1) by 2025 roughly one third of the world's population will be living in countries which are water-stressed, at least by conventional criteria; (2) nevertheless, macro evidence does not portend that the world will be unable to feed its growing population at that time; (3) interstate armed conflicts over water, which were not very important in the last quarter of the twentieth century, seem unlikely to become more intense in the coming decades, especially since most countries have not utilized the enormous possibilities for saving scarce water.
Trade, openness, and domestic conflict: An empirical investigation for Latin America
Authors: Bhattacharya Prasad S. , Thomakos Dimitrios D.
Published: May 2014

The article reports results of an empirical investigation into trade, openness, and domestic conflict for several Latin American countries. It addresses two main issues: (1) whether variations in trade openness affect the likelihood of the onset of domestic conflict and (2) once initiated, how variations in openness affect conflict duration. For the period 1973- 1995, and controlling for numerous sociopolitical, institutional, and economic factors, our findings suggest that (1) increased trade openness reduces the chance for domestic conflict onset as well as the intensity of domestic conflict and (2) over-reliance on agricultural exports, which can be a consequence of increased openness, is the main factor sustaining conflict. Conflict mitigation policies should keep in mind the role tradable agricultural goods play in this region of the world.
Duration of Protection After Infant Hepatitis B Vaccination Series
Authors: Middleman Amy B. , Baker Carol J. , Kozinetz Claudia A. , Kamili Saleem , Nguyen Chi , Hu Dale J. , Spradling Philip R.
Published: May 2014

BACKGROUND:

Little is known about duration of protection after the infant primary series of hepatitis B (HB) vaccine in settings of low HB endemicity. This study sought to determine the proportion of adolescents immunized as infants who had protective titers of antibody to hepatitis B surface antigen (anti-HBs) before and after a challenge dose of vaccine.

METHODS:

US-born 16- through 19-year-olds who received a recombinant HB vaccine 3-dose series initiated within 7 days of birth (group 1) or at ≥4 weeks of age (group 2) and completed by 12 months of age were enrolled. Participants had serologic testing before and 2 weeks after randomization to receive a challenge dose of 10 µg or 20 µg of Engerix-B. Baseline and postchallenge levels of anti-HBs were compared by group, challenge dosage, and demographic and behavioral characteristics.

RESULTS:

At baseline, 24% had protective anti-HBs levels of ≥10 IU/mL; 92% achieved protective levels after challenge dose. Although group 1 had a lower proportion of seroprotection at baseline, group and challenge dosage were not associated with postchallenge proportion of seroprotection. Being in group 2, higher test dosage, higher baseline geometric mean titer, and nonwhite race were associated with significantly higher geometric mean titer after challenge dose.

CONCLUSIONS:

More than 90% of study participants immunized against HB as infants exhibited a seroprotective response to a challenge dose of vaccine. Duration of protection from the primary infant HB vaccine series extended through the adolescent years in the setting of low HB endemicity.
Follow-up Formula Consumption in 3- to 4-Year-Olds and Respiratory Infections: An RCT
Authors: Li Fei , Jin Xingming , Liu Bryan , Zhuang Weihong , Scalabrin Deolinda
Published: May 2014

OBJECTIVE:

Children are vulnerable to diet inadequacies, which may affect immune function. Our objective was to determine if a follow-up formula (FUF) containing DHA, the prebiotics PDX and GOS, and yeast β-glucan affects incidence of respiratory infections and diarrheal disease in healthy children.

METHODS:

In a double-blind, randomized, controlled, prospective trial, 3-4 year old children were fed 3 servings per day of either a FUF with 25 mg DHA, 1.2 g PDX/GOS, and 8.7 mg yeast β-glucan per serving or an unfortified, cow’s milk-based beverage (control) for 28 weeks. Fecal and blood samples were collected to assess immune markers and iron/zinc status. Incidence of acute respiratory infections (ARI), diarrheal disease, and antibiotic treatment were obtained from medical records.

RESULTS:

The FUF group had fewer episodes and shorter duration of ARI (mean days [SE]; control = 4.3 [0.2]; FUF = 3.5 [0.2]; P = .007), less antibiotic use (n [%]; control = 21 [14%]; FUF = 8 [5%]; P = .01), and fewer missed days of day care due to illness. No diarrheal disease was diagnosed in either group. The FUF group had higher interleukin-10 and white blood cell count at the end of the study. There were no differences in hemoglobin, serum ferritin and zinc, or fecal secretory immunoglobulin A.

CONCLUSIONS:

Daily consumption of a FUF was associated with fewer episodes and shorter duration of ARI, as well as less antibiotic use. The children who consumed the FUF had increased interleukin-10 and white blood cells, suggesting an antiinflammatory mechanism and/or an increase of effector immune cells.