bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of lactase persistence polymorphism in ancient and present‐day Hungarian populations
Authors: Nagy Dóra , Tömöry Gyöngyvér , Csányi Bernadett , Bogácsi‐Szabó Erika , Czibula Ágnes , Priskin Katalin , Bede Olga , Bartosiewicz László , Downes C. Stephen , Raskó István 
Published: March 2011

AbstractThe prevalence of adult‐type hypolactasia varies ethnically and geographically among populations. A C/T–13910 single nucleotide polymorphism (SNP) upstream of the lactase gene is known to be associated with lactase non‐persistence in Europeans. The aim of this study was to determine the prevalence of lactase persistent and non‐persistent genotypes in current Hungarian‐speaking populations and in ancient bone samples of classical conquerors and commoners from the 10th–11th centuries from the Carpathian basin; 181 present‐day Hungarian, 65 present‐day Sekler, and 23 ancient samples were successfully genotyped for the C/T‐13910 SNP by the dCAPS PCR‐RFLP method. Additional mitochondrial DNA testing was also carried out. In ancient Hungarians, the T‐13910 allele was present only in 11% of the population, and exclusively in commoners of European mitochondrial haplogroups who may have been of pre‐Hungarian indigenous ancestry. This is despite animal domestication and dairy products having been introduced into the Carpathian basin early in the Neolithic Age. This anomaly may be explained by the Hungarian use of fermented milk products, their greater consumption of ruminant meat than milk, cultural differences, or by their having other lactase‐regulating genetic polymorphisms than C/T‐13910. The low prevalence of lactase persistence provides additional information on the Asian origin of Hungarians. Present‐day Hungarians have been assimilated with the surrounding European populations, since they do not differ significantly from the neighboring populations in their possession of mtDNA and C/T‐13910 variants. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Vertebral pathologies in two early modern period (16th–19th century) populations from Croatia
Authors: Novak Mario , Šlaus Mario 
Published: March 2011

AbstractIn order to test to what degree Schmorl's nodes (SN), osteophytosis of the vertebral bodies (VO), and osteoarthritis of the articular facets (OA) are useful indicators of activity‐related stress, an analysis of their frequencies and severity of expression was conducted in two early Modern period skeletal samples from Croatia—Koprivno and Sisak. Historic and contemporary ethnographic sources suggest that living conditions were more demanding in Koprivno, and that a sexual division of labor existed in both populations. A total of 2,552 vertebral bodies (990 from Koprivno and 1,562 from Sisak) and 5,186 articular facets (2,135 from Koprivno and 3,051 from Sisak) were analyzed. Koprivno exhibits significantly higher total frequencies of SN, VO, and OA than Sisak, and the total frequencies of SN and OA in both series are significantly higher in males. When, however, the series were analyzed by age and sex categories, the same trend was noted only in SN. The frequencies and severity of VO and OA could not be interpreted in keeping with the historic and contemporary ethnographic sources and were additionally, unlike SN, found to be strongly correlated with increased age. This study, therefore, suggests that while SN are useful indicators of different lifestyles and/or different activity patterns between various archaeological populations, VO and OA are—possibly because of their more varied etiologies—less useful markers of activity‐related stress. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Optimization of biomethane production by anaerobic digestion of palm oil mill effluent using response surface methodology
Authors: Saleh A. F. , Kamarudin E. , Yaacob A. B. , Yussof A. W. , Abdullah M.A. 
Published: March 2011

ABSTRACTThis study investigated the effects of factors namely temperature, palm oil mill effluent (POME) volume, inoculum volume, and co‐substrate addition such as oil palm empty fruit bunch (EFB) and palm kernel on the anaerobic digestion process for biogas and methane production. Response surface methodology by the Box‐Behnken design verified that the specific biogas production rate and methane yield were mainly affected by operating temperature and co‐substrate addition. The optimal conditions for the maximum specific biogas production rate (0.0574 m3/ kg chemical oxygen demand per day) and methane yield (25.6%) have been predicted by multiple response optimization and verified experimentally at 47.8 °C operating temperature, 50.4 mL POME volume, and 5.7 g EFB addition. The error percentage between experimental and predicted values which were around 5% for methane composition and 12% for specific biogas production rate suggests the good predictability of the model. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
Polypropylene surface modification with stearyl alcohol ethoxylates to enhance wettability
Authors: Datla Vasantha M. , Shim Eunkyoung , Pourdeyhimi Behnam 
Published: March 2011

AbstractStearyl alcohol ethoxylated additives were melt‐blended in polypropylene (PP) films, and the characteristics of the modified films were investigated. The melt blending of stearyl alcohol ethoxylates improved the hydrophilicity of the PP films through additive surface segregation. Surface specific techniques, such as X‐ray photoelectron spectroscopy and time‐of‐flight secondary‐ion mass spectrometry, were used to study the surface compositions of the samples modified with ethoxylated additives. This revealed that the surface concentrations of the additives were significantly higher than the bulk concentrations in all samples. In addition, the surface compositions of the additive‐modified samples continuously changed, even after the films were fully solidified. We also found that the resulting surface characteristics were very dynamic, so the melt‐additive‐containing polymer surfaces responded to water exposure, and their surface properties and morphologies were altered as a result. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polyelectrolyte complexes from polyethylene imine/acetone formaldehyde sulfite polycondensates: A novel reagent for effective fluid loss control of oil well cement slurries
Authors: Dugonjić‐Bilić Fatima , Plank Johann 
Published: March 2011

AbstractWhen used by itself, polyethylene imine (PEI) does not perform well as cement fluid loss additive. Its combination with acetone formaldehyde sulfite (AFS) polycondensate, however, exhibits excellent filtration control. The mechanism underlying this synergistic effect was studied and the conditions producing best results were determined. For optimum performance, PEI and AFS must be reacted with each other to yield a polyelectrolyte complex (PEC) (d ∼ 5–10 μm), which effectively plugs the pores of the cement filter cake. Composition, size, and effectiveness of the PEC are strongly influenced by the anionic charge amount of the AFS dispersant. Ionic interactions between cationic imine functionalities of PEI and anionic sulfonate groups existing in AFS were confirmed by conductivity, infrared, zeta potential, and particle size measurements. For AFS samples possessing different degrees of sulfonation, the largest particle size and hence best fluid loss performance of the PEC was found to occur at a PEI:AFS molar ratio, which corresponds to neutral charge. Occurrence of large PEC particles (d ∼ 5 μm) within the cement filter cake pores was visualized by scanning electron microscopy, and their stability in highly alkaline cement pore solution was confirmed by particle size measurement. Other anionic polyelectrolytes may be used to yield such PECs with PEI to provide effective fluid loss control for cement slurries. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Combination effect of organics‐modified montmorillonite with intumescent flame retardants on thermal stability and fire behavior of polyethylene nanocomposites
Authors: Huang Guobo , Zhu Bingchun , Shi Haibo 
Published: March 2011

AbstractA combination effect was observed between organics‐modified montmorillonite (OMMT) and a novel intumescent flame retardant, diphenylmethanamine spirocyclic pentaerythritol bisphosphonate (PSPD), in low‐density polyethylene (LDPE) nanocomposites. The results from X‐ray diffraction and transmission electron microscopy showed that montmorillonite can achieve better dispersion in LDPE/PSPD blend matrix, and exfoliated LDPE/PSPD/OMMT nanocomposites are formed. Thermal stability and flammability properties were investigated by thermogravimetric analysis and cone calorimeter tests. The combination effect of PSPD and montmorillonite improved thermal stability and reduced significantly the flammability (including heat release rate, total heat release, average mass loss rate, etc.). The peak heat release rate of LDPE/PSPD/OMMT is reduced by about 51% compared with pure LDPE. The morphology and composition of residues generated after cone calorimeter tests were investigated by scanning electron microscopy and X‐ray photoelectron spectroscopy. The scanning electron microscopy images showed that the compact and dense intumescent char is formed for LDPE/PSPD/OMMT nanocomposite after combustion. The results of X‐ray photoelectron spectroscopy confirmed that the carbon content of the char for LDPE/PSPD/OMMT increases obviously by the combination effect of PSPD and montmorillonite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Fracturing fluid cleanup by controlled release of enzymes from polyelectrolyte complex nanoparticles
Authors: Barati Reza , Johnson Stephen J. , McCool Stan , Green Don W. , Willhite G. Paul , Liang Jenn‐Tai 
Published: March 2011

AbstractWater‐based polymer gels are used widely in the oil and gas industry to viscosify fluids used in the hydraulic fracturing of production wells, where they serve to increase the force applied to the rock and to improve the transport of proppants used to maintain the fracture after formation. After fracturing, the gel must be degraded to a low viscosity with enzymes or gel breakers. Existing systems add the breaker either directly to the gelant or encapsulated in beads that are crushed when the applied pressure is released and the fractures close. In the former case, the gel may be broken prematurely, and this may prevent efficient fracture propagation and proppant transport, whereas in the latter case, the breaker may not be uniformly distributed throughout the gel, with the result that the gel is incompletely broken and the hydraulic conductivity of the well is reduced. To obtain delayed release, combined with the homogeneous distribution of enzyme throughout the gel, polyethylenimine–dextran sulfate polyelectrolyte complexes were used to entrap pectinase. Such particles were originally developed to entrap pharmaceuticals, and we previously demonstrated their ability to delay the release of gel crosslinking agents for oilfield applications. The degradation of both the viscosity and viscoelastic moduli of borate‐crosslinked guar gel by pectinase loaded in polyelectrolyte nanoparticles was delayed by up to 12 h, compared to about 2 h for equivalent systems where the pectinase was not entrapped. The combination of homogeneous mixing and the delayed release of enzymes packaged in polyelectrolyte complex nanoparticles showed promise for improved cleanup after hydraulic fracturing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis, speed of ultrasound and associated acoustical parameters of epoxy acrylate of 9,9′‐bis (4‐hydroxy phenyl) anthrone‐10 solutions
Authors: Bhuva B. D. , Parsania P. H. 
Published: March 2011

AbstractDensity (ρ), viscosity (η), and speed of ultrasound (U) (2 MHz) of pure solvents (chloroform, THF, and 1,4‐dioxane) and solutions of epoxy acrylate of 9,9′‐bis(4‐hydroxy phenyl) anthrone‐10 (EAAN) have been investigated at 303, 308, and 313 K. Specific acoustical impedance (Z), isentropic compressibility (κs), intermolecular free path length (Lf), classical absorption coefficient (α/f2)cl, and viscous relaxation time (τ) have been determined from ρ, η, and U data and are correlated with concentration. Z, (α/f2)cl, and τ increased with C and decreased with T, while κs and Lf decreased with C and increased with T in the solvent systems studied. A fairly good to excellent correlation between a given parameter and concentration is observed in solvent systems studied. Linear increase or decrease of acoustical parameters with concentration and temperature indicated existence of strong molecular interactions. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Alginic acid‐g‐poly(N‐vinylformamide) graft copolymer: Synthesis, characerization, swelling, and flocculation property
Authors: Sand Arpit , Yadav Mithilesh , Mishra Dinesh Kumar , Behari Kunj 
Published: March 2011

AbstractThe graft copolymer of N‐vinylformamide with alginic acid was synthesized by free radical polymerization using potassium peroxymonosulphate and thiourea as redox pair in inert atmosphere. The optimum conditions for maximum grafting have been determined by varying the concentrations of N‐vinylformamide, potassium peroxymonosulphate, thiourea, sulfuric acid, alginic acid as well as time duration and temperature. The grafting parameters increase up to the certain concentrations of N‐vinylformamide, potassium peroxymonosulhate, thiourea, and hydrogen ion while thereafter grafting parameters decrease. The effect of alginic acid concentration on grafting parameters has been observed to decrease continuously. It has also been found that grafting parameters increase up to certain time and temperature, respectively, and thereafter decrease. The swelling properties of graft copolymer in terms of swelling ratio and percent swelling are investigated. Flocculation property of pure and grafted sample for both coking and noncoking coals is also investigated for the treatment of coal mine waste water. The graft copolymer has been characterized by Fourier transform infrared spectroscopy as well as thermogravimetic analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Combining atom transfer radical polymerization and melt compounding for producing PMMA/clay nanocomposites
Authors: Lerari D. , Peeterbroeck S. , Benali S. , Benaboura A. , Dubois Ph. 
Published: March 2011

AbstractNanocomposites based on poly (methyl methacrylate) (PMMA) and 3 wt % of clay (montomorillonite) organomodified with alkylammonium cations bearing alkyl halide function (OCTANBriBBr‐CL) have been obtained by melt blending. The “nanohybrid” masterbatch approach, already used within other matrices, has also been tested to produce this type of material. Accordingly, highly filled (∼ 30 wt %) PMMA‐OCTANBriBBr‐CL nanohybrid has been synthesized by atom transfer radical polymerization (ATRP) of MMA as in situ initiated from the alkyl halide functions decorating the nanoclay surface. This nanohybrid, i.e., PMMA‐grafted organomodified clay, has been added as masterbatch and melt‐blended within commercial PMMA. A significantly better clay nanoplatelet dispersion of the samples prepared via the masterbatch process was evidenced by wide‐angle X‐ray diffraction (WAXD) and transmission electron microscopy (TEM). As a result, these exfoliated nanocomposites proved to be characterized by better thermal and mechanical properties than the more conventional physical blends, as evidenced by thermogravimetrical analysis (TGA) and dynamical mechanical analysis (DMTA), respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Siderophore‐Mimetic hydrogel for iron chelation therapy
Authors: Mohammadi Zahra , Xie Sheng‐Xue , Golub Allison L. , Gehrke Stevin H. , Berkland Cory 
Published: March 2011

AbstractTwo, three dihydroxybenzoic acid (DHBA), a portion of the metal chelating domain of enterobactin, was immobilized on crosslinked organic polymer polyallylamine (PAAm) and used as a chelating agent for iron removal from aqueous solutions. The swelling behavior of PAAm and PAAm hydrogels conjugated with dihydroxybenzoic acid and the effect of contact time on the swelling and binding capacity of the hydrogel was investigated at several pH values to define the absorption mechanism. Iron uptake kinetics followed the pseudosecond order Ho model and equilibrium was described by either Temkin or Freundlich isotherms. Maximum chelating capacities of the hydrogels were found to be 500–1500 mg Fe3+ g−1 and 1500–2500 mg Fe2+ g−1 for PAAm and PAAm/DHBA hydrogels, respectively, depending on the pH of the media. The selectivity of the conjugate hydrogel toward ferric ions was studied at several different pH values. At every pH ranging from 2 to 7.5, the conjugate hydrogel showed relatively high binding affinity for ferric ions. The selective and rapid, high affinity binding of iron by this siderophore‐mimetic hydrogel offers potential application as a nonabsorbed chelator for iron in the gastrointestinal tract of patients suffering from iron overload diseases. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of novel, highly crystalline poly(vinyl alcohol) microspheres for chemoembolization therapy
Authors: Semenzim Vinícius Ladeia , Basso Glaucia Grazielli , da Silva Danilo Antonio , de Vasconcellos Adriano , Agreli Guilherme , Lima‐Oliveira Ana Paula Marques , Kawasaki‐Oyama Rosa Sayoko , Braile Domingo Marcolino , Nery José Geraldo 
Published: March 2011

AbstractBiodegradable polymeric microspheres can be used to deliver drugs through controlled rate and targeted processes. The drug is released from the particles by drug leaching or degradation of the polymeric matrix. Crystallinity can play a very important role in the degradation of polymeric matrixes; it can affect the drug‐release rate, especially in chemoembolization. Most commercial embolic agents have a low degree of crystallinity, and the correlation between the drug‐delivery rate and the degree of crystallinity is not fully understood. This study presents the appropriated synthesis conditions for the preparation of highly crystalline poly(vinyl alcohol) and poly(vinyl alcohol)/poly(vinyl acetate) microspheres and physicochemical characterizations by scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, and cross‐polarization/magic angle spinning nuclear magnetic resonance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Crystallization behavior of biodegradable poly(L‐lactic acid) filled with a powerful nucleating agent: N,N′‐bis(benzoyl) suberic acid dihydrazide
Authors: Cai Yanhua , Yan Shifeng , Yin Jingbo , Fan Yinqing , Chen Xuesi 
Published: March 2011

AbstractN,N′‐Bis(benzoyl) suberic acid dihydrazide (NA) as nucleating agent for poly(L‐lactic acid) (PLLA) was synthesized from benzoyl hydrazine and suberoyl chloride, which was deprived from suberic acid via acylation. PLLA/NA samples were prepared by melt blending and a hot‐press forming process. The nonisothermal and isothermal crystallization, spherulite morphology, and melting behavior of PLLA/NA with different contents of NA were investigated with differential scanning calorimetry, depolarized‐light intensity measurement, scanning electron microscopy, polarized optical microscopy, and wide‐angle X‐ray diffraction. With the incorporation of NA, the crystallization peak became sharper and shifted to a higher temperature as the degree of supercooling decreased at a cooling rate of 1°C/min from the melt. Nonisothermal crystallization indicated that the presence of NA accelerated the overall PLLA crystallization. In isothermal crystallization from the melt, the presence of NA affected the isothermal crystalline behaviors of PLLA remarkably. The addition of NA led to a shorter crystallization time and a faster overall crystallization rate; this meant that there was a heterogeneous nucleation effect of NA on the crystallization of PLLA. With the addition of 0.8% NA, the crystallization half‐time of PLLA/NA decreased from 26.5 to 1.4 min at 115°C. The Avrami theory was used to describe the kinetics of isothermal crystallization of the PLLA/NA samples. Also, with the presence of NA, the spherulite number of PLLA increased, and the spherulite size decreased significantly. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Facile preparation of poly(3,4‐ethylenedioxythiophene) nanoparticles via a miniemulsion polymerization process
Authors: Jin Sun‐Mi , Joo Young‐Tae , Park Ye‐Ji , Kim Yangsoo 
Published: March 2011

AbstractPoly(3,4‐ethylenedioxythiophene) (PEDOT) nanoparticles were prepared via a miniemulsion polymerization process. The chemical oxidative polymerization of 3,4‐ethylenedioxythiophene (EDOT) occurred in the presence of β‐1,3‐glucan with the injection of an aqueous oxidant solution, and the nanodroplets of EDOT were transformed to PEDOT nanoparticles dispersed in the aqueous medium. The aqueous emulsion of PEDOT nanoparticles showed relatively long emulsion stability (> 8 weeks), and the recovered solid nanoparticles were also redispersible in deionized water without deposition. The size and size distribution of PEDOT nanoparticles could be controlled by adjusting the operating conditions of the ultrasonifier before the polymerization process. The building‐up of a shearing force decreases the size of the PEDOT nanoparticles and also causes the occurrence of a multimodal size distribution for the PEDOT nanoparticles. The electrical conductivity of the PEDOT nanoparticles was 0.28–1.20 S cm−1. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Fast and efficient synthesis of high molecular weight poly(epsilon‐caprolactone) diols by microwave‐assisted polymer synthesis
Authors: Gotelli Gustavo A. , Bonelli Pablo , Abraham Gustavo A. , Sosnik Alejandro 
Published: March 2011

AbstractBecause of advantageous features such as shorter reaction times, greater yields, limited generation of by‐products and relatively easy and straightforward scale‐up, microwave‐assisted synthesis has become a very appealing tool in organic synthesis. Conversely, its implementation in the context of the synthesis of biomaterials for biopharmaceutical applications has been more limited. The present work reports on the fast and efficient microwave‐assisted synthesis of poly(ethylene glycol) (PEG)‐initiated poly(ε‐caprolactone) diols (PCL) by the ring‐opening polymerization (ROP) of ε‐caprolactone using stannous octanoate as catalyst. Since the PEG content in the synthesized copolymers was extremely low (0.2–1.9%), products were highly hydrophobic and displayed the intrinsic thermal properties of pure PCL. As opposed to the more time‐consuming conventional thermally‐driven synthesis that usually demands 2–3 h, the microwave technique resulted in intermediate to high molecular weight PEG‐PCL derivatives within 10–15 min. The influence of different parameters affecting the synthetic process, namely monomer‐to‐initiator ratio, reaction time, catalyst concentration and the presence, type, and concentration of solvent were thoroughly investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011