bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulmonary function and emphysema in Williams–Beuren syndrome
Authors: Wan Emily S. , Pober Barbara R. , Washko George R. , Raby Benjamin A. , Silverman Edwin K.
Published: February 2010

Williams–Beuren syndrome (WBS) is caused by a submicroscopic deletion on chromosome 7q11.23 that encompasses the entire elastin (ELN) gene. Elastin, a key component of elastic fibers within the lung, is progressively destroyed in emphysema. Defects in the elastin gene have been associated with increased susceptibility towards developing chronic obstructive pulmonary disease (COPD) and emphysema in both humans and mice. We postulate that hemizygosity at the elastin gene locus may increase susceptibility towards the development of COPD and emphysema in subjects with WBS. We describe an adult subject with WBS who was a lifelong non‐smoker and was found to have moderate emphysema. We also examined the pulmonary function of a separate cohort of adolescents and young adults with WBS. Although no significant spirometric abnormalities were identified, a significant proportion of subjects reported respiratory symptoms. Thus, while significant obstructive disease does not appear to be common in relatively young adults with WBS, subclinical emphysema and lung disease may exist which possibly could worsen with advancing age. Further investigation may elucidate the pathogenesis of non‐smoking‐related emphysema. © 2010 Wiley‐Liss, Inc.
Massive cranial osteolysis, skin changes, growth retardation and developmental delay: Gorham syndrome with systemic manifestations?
Authors: Girisha K.M. , Ganesh H.K. , Rao Lakshmi , Srilatha P.S.
Published: February 2010

We report on a 16‐month‐old girl with multiple swellings on her skull due to massive osteolysis, growth retardation, facial anomalies, and wrinkly skin with mosaic hypopigmentation. She also had severe hypercalcemia, which gradually returned to normal levels. The condition likely represents Gorham syndrome with systemic manifestations. © 2010 Wiley‐Liss, Inc.
Absence of signs of systemic involvement in four patients with bilateral multiple facial angiofibromas
Authors: Hunter Alasdair G.W. , Nezarati Marjan M. , Velsher Lea
Published: February 2010

Facial angiofibromas are a major diagnostic sign for tuberous sclerosis (TS) and MEN1, and the former is probably the first disease to be considered by a geneticist when such lesions are found. They occur in up to 90% of persons with TS and 40–80% of individuals with MEN1. Early onset facial angiofibromas that are not associated with any other systemic sign appear to be unusual, and their occurrence can leave the clinician with some uncertainty as to their significance, as well as how to proceed. In this article we describe four patients with what appear to be isolated, bilateral facial angiofibromas. We discuss the significance of these lesions with respect to the conditions in which they have been seen, review prior reports of apparently isolated angiofibromas, and provide some rough calculations as to how likely it would be for an underlying systemic condition to be overlooked after different levels of investigation have been performed. We also look at some aspects of the financial cost/benefit ratio of further investigation of TS beyond a clinical examination. © 2010 Wiley‐Liss, Inc.
Vegetation correlates of gibbon density in the peat‐swamp forest of the Sabangau catchment, Central Kalimantan, Indonesia
Authors: Hamard Marie , Cheyne Susan M. , Nijman Vincent
Published: February 2010

Understanding the complex relationship between primates and their habitats is essential for effective conservation plans. Peat‐swamp forest has recently been recognized as an important habitat for the Southern Bornean gibbon (Hylobates albibarbis), but information is scarce on the factors that link gibbon density to characteristics of this unique ecosystem. Our aims in this study were firstly to estimate gibbon density in different forest subtypes in a newly protected, secondary peat‐swamp forest in the Sabangau Catchment, Indonesia, and secondly to identify which vegetation characteristics correlate with gibbon density. Data collection was conducted in a 37.1 km2 area, using auditory sampling methods and vegetation “speed plotting”. Gibbon densities varied between survey sites from 1.39 to 3.92 groups/km2. Canopy cover, tree height, density of large trees and food availability were significantly correlated with gibbon density, identifying the preservation of tall trees and good canopy cover as a conservation priority for the gibbon population in the Sabangau forest. This survey indicates that selective logging, which specifically targets large trees and disrupts canopy cover, is likely to have adverse effects on gibbon populations in peat‐swamp forests, and calls for greater protection of these little studied ecosystems. Am. J. Primatol. 72:607–616, 2010. © 2010 Wiley‐Liss, Inc.
Human–nonhuman primate interactions amongst Tikuna people: perceptions and local initiatives for resource management in Amacayacu in the Colombian Amazon
Authors: Parathian Hannah E. , Maldonado Angela M.
Published: February 2010

This study assesses the impact of hunting on the densities of nonhuman primates in two indigenous Tikuna territories (Mocagua and San Martín), overlapping Amacayacu National Park in the Colombian Amazon. Large‐bodied primates were once favored prey by Tikunas, but are now rarely hunted owing to the diminishing primate populations. We evaluate the effect of a hunting ban on woolly monkeys (Lagothrix lagothricha) by the residents of Mocagua, using qualitative and quantitative methods. Hunting records showed that from February 2005 to February 2009, a total of 25,142 kg of mammal bushmeat were harvested in Mocagua and San Martín. Primates constituted 345 kg of the total harvest. From 223 kg of large‐bodied primates extracted for subsistence purposes, 160 kg were hunted in San Martín and 64 kg in Mocagua. Large‐bodied primates made up 70% of the total primate biomass in Mocagua (398 kg/km2) and 22% in San Martín (199 kg/km2). From dietary records, we found bushmeat constituted 30% of protein consumption in Mocagua and 37% in San Martín. Primates were absent in records from Mocagua, and appeared only three times in those from San Martín suggesting inconsistencies with hunting data. Despite its moderate consumption, bushmeat was identified as a highly valued food source during focus group activities. Primate pet‐keeping and part utilization were observed in San Martín but not in Mocagua, possibly as a consequence of fewer primates being hunted. We suggest that Mocagua provides an example of how community‐based conservation strategies can be achieved, where opportunities for employment in tourism and alternative food sources are available. Am. J. Primatol. 72:855–865, 2010. © 2010 Wiley‐Liss, Inc.
Peptidbasierte Verfahren zur Herstellung nanostrukturierter anorganischer Materialien
Authors: Chen Chun‐Long , Rosi Nathaniel L.
Published: February 2010

Mit ihrer einzigartigen sequenzspezifischen Selbstorganisation und der Fähigkeit zur Substraterkennung spielen Peptide in natürlichen Systemen eine entscheidende Rolle bei der Steuerung der Biomineralisation anorganischer Nanostrukturen und der Entstehung von Weichgewebe. Daher sind Peptide auch besonders wertvoll für die Herstellung neuer Materialien, und Forscher vieler Disziplinen bedienen sich heute dieser Moleküle, um die Synthese anorganischer Nanostrukturen und den Aufbau weicher Biomaterialien zu steuern. In diesem Aufsatz schildern wir die Entwicklungen auf diesem Gebiet, wobei unser spezielles Augenmerk der Fähigkeit von Peptiden gilt, die Zusammensetzung und Struktur neuer anorganischer Materialien zu steuern.
Thermal properties of graphite‐loaded nitrile rubber/poly(vinyl chloride) blends
Authors: Mansour S. A. , Al‐Ghoury M. E. , Shalaan E. , El Eraki M. H. I. , Abdel‐Bary E. M.
Published: February 2010

The thermal properties (thermal conductivity, thermal diffusivity, and specific heat capacity) of nitrile rubber (NBR)/poly(vinyl chloride) (PVC) blends were measured in the temperature range of 300–425 K. The incorporation of graphite into the NBR/PVC (30/70) matrix improved its thermal properties. Moreover, these properties slightly changed with the temperature. The thermal conductivity values of the prepared samples were compared with values modeled according to the Maxwell–Eucken, Cheng–Vachon, Lewis–Nielsen, geometric mean, and Agari–Uno models. The Agari–Uno model best predicted the effective thermal conductivity for the whole range of blend ratios and for the whole range of graphite contents in NBR/PVC (30/70)/graphite composites. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Morphology and thermal properties of maleic anhydride grafted polypropylene/ethylene–vinyl acetate copolymer/wood powder blend composites
Authors: Dikobe Dorine Geneth , Luyt Adriaan Stephanus
Published: February 2010

Maleic anhydride grafted polypropylene (MAPP) was blended with ethylene–vinyl acetate (EVA) copolymer to form MAPP/EVA polymer blends. Wood powder (WP) was mixed into these blends at different weight fractions to form MAPP/EVA/WP blend composites. Differential scanning calorimetry (DSC) analysis of the blends showed small melting peaks between those of EVA and MAPP, which indicated interaction and cocrystallization of fractions of EVA and MAPP. The presence of MAPP influenced the EVA crystallization behavior, whereas the MAPP crystallization was not affected by the presence of EVA. Scanning electron microscopy, Fourier transform infrared spectroscopy, and DSC results show that the WP particles in the MAPP/EVA blend were in contact with both the MAPP and EVA phases and that there seemed to be chemical interaction between the different functional groups. This influenced the crystallization behavior, especially of the MAPP phase. The thermogravimetric analysis results show that the MAPP/EVA blend had two degradation steps. An increase in the WP content in the blend composite led to an increase in the onset of the second degradation step but a decrease in onset of the first degradation step. The presence of WP in the blend led to an increase in the modulus but had almost no influence on the tensile strength of the blend. The dynamic mechanical analysis results confirm the interaction between EVA and MAPP and show that the presence of WP only slightly influenced the dynamic mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Vibrational dynamics of gamma form of nylon 6 (γNY6)
Authors: Shukla Sandeep Kumar , Kumar Naresh , Tandon Poonam , Gupta Vishwambhar Dayal
Published: February 2010

Normal mode analyses including phonon dispersion have been performed, to understand completely the spectra (Infrared/Raman) of (γNY6), using Wilson GF matrix method and Urey‐Bradley force field. Characteristic features of the dispersion curves such as repulsion and region of high density‐of‐states have been explained. Heat capacity measurements have been interpreted and the limitation of this work discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Characterization of chemically modified wood fibers using FTIR spectroscopy for biocomposites
Authors: Gwon Jae Gyoung , Lee Sun Young , Doh Geum Hyun , Kim Jung Hyeun
Published: February 2010

Chemical modifications of wood fibers (Lignocel® C120) were performed for biocomposite applications, and chemically modified wood fibers were analyzed by FTIR spectroscopy. NaOH treatment showed band shifts from Cell‐I to Cell‐II in FTIR spectra from 2902 cm−1, 1425 cm−1, 1163 cm−1, 983 cm−1, and 897 cm−1 to 2894 cm−1, 1420 cm−1, 1161 cm−1, 993 cm−1, and 895 cm−1 and the change in peak height at 1111 cm−1 and 1059 cm−1 assigned for Cell‐I structure. Silane treatment showed peak changes at 1200 cm−1 assigned as SiOC band, at 765 cm−1 assigned as SiC symmetric stretching bond, at 700 cm−1 assigned as SiOSi symmetric stretching, and at 465 cm−1 assigned as SiOC asymmetric bending. Benzoyl treatment resulted in an increase in the carbonyl stretching absorption at 1723 cm−1 and in band characteristics of aromatic rings (1604 cm−1 and 710 cm−1) and a strong absorption at 1272 cm−1 for CO band in aromatic ring. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Creep rupture properties of homopolymer, copolymer, and terpolymer based on poly(oxymethylene)
Authors: Tajima Yoshihisa , Itoh Takahito
Published: February 2010

Polyacetal copolymers were prepared by cationic ring‐opening copolymerizations of 1,3,5‐trioxane (TOX) with 1,3‐dioxolane (DOX), and polyacetal terpolymers were prepared by terpolymerizations of TOX, DOX, and 2‐ethylhexyl glycidyl ether (EHGE). Polyacetal polymers with three different structures such as polyacetal homopolymers, polyacetal copolymers, and polyacetal terpolymers were compared in the mechanical properties and the creep characteristics, and discussed from the view point of the polymer structure. The polyacetal copolymers and the polyacetal terpolymers were determined by 1H‐MNR measurement. About 80 mol % of DOX and EHGE amounts in feed were incorporated randomly into the each polymer. From the plots of the degree of crystallinity (Xc) versus the tensile strength, the tensile strength and crystallintiy of the polyacetal homopoymers are higher than those of the polyacetal copolymers and the polyacetal terpolymers. However, the tensile strength does not decrease linearly with a decrease in the crystallinity among the polyacetal polymers with three different structures, the polyacetal homopolymer, the polyacetal copolymers, and the polyacetal terpolymers. Creep rupture was characterized by the activation volume, υc, value in Zhurkov's equation, which can be estimated from the slope in the plots of load versus log (rupture time) at 80°C. The polyacetal polymers with higher molecular weight have larger values of the activation volume than those with lower molecular weight. When the activation volume values are compared among the polyacetal polymers with the same molecular weights, they increase in the following order: the polyacetal homopolymers < the polyacetal copolymers < polyacetal terpolymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Comparative investigation of the structure and properties of ferroelectric poly(vinylidene fluoride) and poly(vinylidene fluoride–trifluoroethylene) thin films crystallized on substrates
Authors: Chen Shuting , Yao Kui , Tay Francis Eng Hock , Chew Lydia Li Shan
Published: February 2010

Poly(vinylidene fluoride) (PVDF) and copolymers of vinylidene fluoride and trifluoroethylene [P(VDF/TrFE)s] were deposited on silicon substrates, and their structure and properties were comparatively investigated. Compared to P(VDF/TrFE), which is the polymer material currently most dominant for ferroelectric thin‐film devices applications, our β‐phase PVDF homopolymer thin film demonstrated several advantages, such as higher dielectric breakdown strength, improved polarization fatigue endurance, and larger ferroelectric polarization at elevated temperatures with improved thermal stability. The reasons for the observed different characteristics between the PVDF and P(VDF/TrFE) thin films were analyzed on the basis of their different structures and morphologies. The results indicate that the low‐cost β‐phase PVDF homopolymer thin films have great potential as an alternative to P(VDF/TrFE) for ferroelectric and piezoelectric thin‐film‐device applications. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fabrication and properties of superabsorbent complex gel beads composed of hydrolyzed polyacrylamide and chitosan
Authors: Cao Jie , Tan Yebang , Che Yuju , Ma Qiang
Published: February 2010

A novel method for preparing complex beads composed of hydrolyzed polyacrylamide (HPAM) and chitosan, based on the electrostatic attraction between COO− of HPAM and Al3+ and between COO− and NH3+ of chitosan, was established. In the two‐stage crosslinking process, first Al3+ was used as a crosslinking agent for the crosslinking of HPAM molecules, which were used as the skeleton structure of the gel beads. In the second stage, chitosan diffused into the skeleton structure. The gel beads were characterized with scanning electron microscopy, inductively coupled plasma mass spectrometry, Fourier transform infrared spectroscopy, and thermogravimetric analysis. There was a chitosan component in the gel beads, and these gel beads had porous and rough surfaces. The swelling properties of the HPAM–chitosan gel beads were measured in water, in acidic, neutral, and alkaline buffers, and in different saline solutions. The swelling ratio was as high as 3675 g/g in water and 170 g/g in a 0.15 mol/L NaCl solution. The beads showed pH sensitivity in buffers of different pH values and salt sensitivity in different saline solutions. The order of the equilibrium absorbency of the gel beads in different saline solutions was Na+ > K+ > Mg2+ > Ca2+ > Al3+. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Gas permeation related to the moisture sorption in films of glassy hydrophilic polymers
Authors: Laksmana F.L. , Kok P.J.A. Hartman , Frijlink H.W. , Vromans H. , Van Der Voort Maarschalk K.
Published: February 2010

The purpose of this article is to elucidate the effect of integral sorption of moisture on gas permeation in glassy hydrophilic polymers. The oxygen and the simultaneous moisture sorption into various hydroxypropyl methylcellulose (HPMC) films were measured under a wide range of relative humidities using sorption analyzer equipment. Correspondingly, the oxygen permeability at different ambient conditions was measured using an oxygen detector. The solubility of oxygen in the HPMC film was found to be affected by the amount of water and therefore by the water state. At low moisture content, the water molecules are present as bound water, which promotes the sorption of oxygen in the HPMC films. At moisture content higher than 5%, water clusters are rapidly formed, which increase the affinity of HPMC polymer towards water rather than towards oxygen molecules, resulting in a decrease of oxygen solubility in the polymer. This was found to be the governing factor for the reduction in the oxygen permeability in glassy HPMC films at high water activity. This proposes a specific interaction between moisture sorption and oxygen transport in coating films like HPMC, which is of important aspect in the coating design and formulation. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of stoichiometric imbalances on the melt condensation polymerization of poly(dodecamethylene terephthalamide) studied by intrinsic viscosity and 13C‐NMR
Authors: Novitsky Theodore , Lange Christopher , Jarrett William , Mathias Lon , Osborn Scott , Ayotte Roger , Manning Steve
Published: February 2010

Poly(dodecamethylene terephthalamide) (PA‐12,T) was synthesized by melt condensation polymerization of 12,T salt with 0, 1, 3, 5, or 10% molar excess of 1,12‐diaminododecane (DA), terephthalic acid (TA), or benzoic acid (BA). Intrinsic viscosities (IV) (0.5 g/dL in 96% H2SO4 at 25°C) were measured to determine relative molecular weight differences. IV was highest for reactions containing 1 and 3 mol % excess DA (1.36 and 1.31 dL/g, respectively), followed by the product of pure 1 : 1 salt (1.25 dL/g). For all concentrations of excess TA and BA, IV was decreased. 13C‐NMR chemical shifts for DA, TA, and BA end groups were identified and their concentrations determined by comparison with the intensity of main chain polymer peaks. A log–log plot of IV versus number average molecular weight calculated from 13C‐NMR data shows a linear trend with Mark‐Houwink constants of K = 55.8 × 10−5 dL/g and α = 0.81. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Comprehensive study of metal on the characteristic properties of epoxy resins
Authors: Mohan Pragyan
Published: February 2010

A series of different type of epoxy resins containing metal(s) have been prepared by the using cobalt acrylate (CoA2), nickel acrylate(NiA2),bismuth acrylate (BiA3) during resinification. The values of epoxide equivalent weight, chlorine content increases whereas hydroxyl content, refractive index decreases in the presence of metal acrylate(s). The influence of complex formation of metal acrylate with ether linkage of epoxy resins were investigated by spectroscopy. Epoxy resins containing cobalt acrylate which was cured by p‐acetylbenzilidinetriphenylarsoniumylide (p‐ABTAY) shows better conducting properties in comparison to NiA2 and BiA3 containing epoxy resins. The dispersion of metal(s) in epoxy resins matrix was confirmed by scanning electron microscope (SEM). The glass transition temperature of epoxy resins containing CoA2 is lower than that of blank epoxy resins and epoxy resins containing bismuth and nickel acrylate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Modification of polypropylene composites containing potassium titanate whisker and talcum
Authors: Mao Shuangming , Wang Jikui , Qiu Chunchang , Guo Weihong , Wang Yaoxian
Published: February 2010

Modified polypropylene was prepared by blending with potassium titanate whisker (PTW) and 10 w/w% talc via Haake extruder followed by injection molding. Reinforced with both PTW and talc, the PP composites exhibited better mechanical properties. The tensile modulus and flexural modulus of PP composites tend to increase with the increasing of whisker concentrations. The talc plays a synergistic role in improving the mechanical properties of composites and reducing cost. Torque measurement shows the PP composites has a good processing condition due to lubrication of PTW. TGA test shows PP composites containing 20 w/w% PTW and 10 w/w% talc is useful for improving PP composite's thermo oxidative stability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Palladium and platinum sorption on a thiocarbamoyl‐derivative of chitosan
Authors: Butewicz A. , Gavilan K. Campos , Pestov A. V. , Yatluk Y. , Trochimczuk A. W. , Guibal E.
Published: February 2010

Immobilizing thiourea onto chitosan allowed using the polymer for the recovery of platinum groups metals (PGMs) in acidic solutions (up to 1–2M HCl concentrations). At low HCl concentration protonated amine groups may sorb chloroanionic metal species (electrostatic attraction mechanism); however, most of sorption proceeds through chelation on sulfur containing groups (less sensitive to acidic conditions). The bi‐site Langmuir equation was used for fitting sorption isotherms. The sorption of PGMs was weakly affected by the composition of the solution (presence of high concentration of anions and base metals). Maximum sorption capacities for Pd(II) and Pt(IV) ranged between 274 and 330 mg g−1 in 0.25M HCl solutions and decreased to 150–198 mg g−1 in 2M HCl solutions: Pd(II) sorption was systematically higher than Pt(IV) sorption. The pseudo‐second rate equation was used for modeling the uptake kinetics. Agitation speed hardly affected uptake kinetics indicating that external diffusion resistance is not the rate controlling step. Desorption yield higher than 85% were obtained using thiourea in 0.1M HCl solution. The adsorbents could be reused for at least three cycles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Semitransparent chitosan‐TiO2 nanotubes composite film for food package applications
Authors: Díaz‐Visurraga J. , Meléndrez M.F. , García A. , Paulraj M. , Cárdenas G.
Published: February 2010

Semitransparent composite films were prepared made from TiO2 nanotubes in chitosan (CS) matrix. Hydrothermally synthesized titanium nanotubes (TiNTs) were dispersed in chitosan matrix in order to produce film‐forming solutions at 0.05 and 0.10% w/v. Structural, topological, optical and thermal properties of these films were evaluated. The antimicrobial activity of films against Salmonella
enterica serovar Typhimurium, Escherichia coli (Gram‐negatives) and Staphylococcus aureus (Gram‐positive) was also investigated. Fourier transform infrared (FTIR) spectra showed effective site‐selective interactions between chitosan and TiNTs. TiNTs prevented the degradation of films, avoiding the oxidization of the glucosamine ring. Characterizing techniques such as, Scanning electron microscopy–energy dispersive spectroscopy (SEM‐EDS) line profile and atomic force microscopy (AFM) were used to examine the TiNTs dispersion within the film. The morphological analysis indicated that the TiNTs were well dispersed and became clustered proportionally to the weight percentage of TiNTs used in the composites. The UV‐Vis spectra showed that TiNTs increased the film absorption in the UV region and the light barrier properties of films remained stable over the storage period. Photoacoustic spectroscopy (PAS) was used to study these films, nondestructively for their thermal effusivity (e). The films were effective in reducing the microbial concentration in the liquid culture for all bacteria tested. The effectiveness was found to dependent on the bacterial strain and TiNTs content. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Mechanical and morphological properties for sandwich composites of wood/PVC and glass fiber/PVC layers
Authors: Mongkollapkit Narudol , Kositchaiyong Apisit , Rosarpitak Vichai , Sombatsompop Narongrit
Published: February 2010

This work manufactured sandwich composites from glass fiber/poly(vinyl chloride) (GF/PVC) and wood/PVC layers, and their mechanical and morphological properties of the composites in three GF orientation angles were assessed. The effects of K value (or viscosity index) of PVC and Dioctyl phthalate (DOP) loading were of our interests. The GF/PVC was used as core layer whereas wood/PVC was the cover layers. The experimental results indicated that PVC with low K value was recommended for the GF/PVC core layer for fabrication of GF/WPVC sandwich composites. The improvement of PVC diffusion at the interface between the GF and the PVC core layer was obtained when using PVC with K value of 58. This was because it could prevent de‐lamination between composite layers which would lead to higher mechanical properties of the sandwich composites, except for the tensile modulus. The sandwich composites with 0° GF orientation possessed relatively much higher mechanical properties as compared with those with 45° and 90° GF orientations, especially for the impact strength. Low mechanical properties of the sandwich composites with 45° and 90° GF orientation angles could be overcome by incorporation of DOP plasticizer into the GF/PVC core layer with the recommended DOP loadings of 5–10 parts per hundred by weight of PVC components. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of nanoTiO2 addition on poly(methyl methacrylate): An exciting nanocomposite
Authors: Chatterjee Amit
Published: February 2010

A systematic research has been conducted to investigate the matrix properties by introducing nanosize TiO2 (5 nm, 2.0–30% by weight) filler into a poly (methyl methacrylate) (PMMA) resin. A twin screw extraction process was developed to disperse the particles into the PMMA. The thermal, mechanical, and viscoelastic properties of the virgin PMMA and nanoTiO2‐PMMA composite were measured. The nanofiller infusion improves the thermal, mechanical and viscoelastic properties of the PMMA. Nanocomposite shows increase in storage modulus (∼ 60%), rubbery modulus (∼ 210%), glass transition temperature (∼ 27%), crosslink density (∼ 213%), initial decomposition temperature (∼ 83% at 1% wt. loss), and activation energy (∼ 141%). Mechanical performance and thermal stability of the nanoTiO2‐PMMA composites are depending on the dispersion state of the TiO2 in the PMMA matrix. Scanning electron microscopic study shows that the particles are well dispersed in the PMMA matrix. They are correlated with loading. Kinetics for thermal degradation analysis was studies. The integral procedural decomposition temperature (IPDT) is enhanced (∼ 117%). The nanocomposites of high activation energy possess high thermal stability. Interrelation of Tg, crosslink density, IPDT, storage modulus, activation energy, and TiO2 weight percent are established. Various reasons for these effects in terms of reinforcing mechanisms have been discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
A novel thermoviscosifying water‐soluble polymer: Synthesis and aqueous solution properties
Authors: Wang Yu , Feng Yujun , Wang Biqing , Lu Zhiyong
Published: February 2010

A novel thermoviscosifying water‐soluble polymer was synthesized by direct free radical copolymerization of acrylamide with a newly‐prepared macromonomer, and its aqueous solution viscosity behavior at different temperatures was preliminarily examined in both pure water and KCl brine in comparison with its homopolyacrylamide counterpart. Thermoviscosifying ability of the copolymer was clearly evidenced in both aqueous media, and the thermoassociative temperature of the copolymer decreased upon increasing KCl content in polymer solution. Under the same conditions, homopolyacrylamide shows only thermothinning behavior and viscosity loss in both pure water and KCl solution. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Kinetic analysis of solid‐state photodimerization reaction of photosensitive monomers and a polymer with cinnamoyl moieties
Authors: Jiao Yang , Guo Jinbao , Dong Xiaoming , Li Rui , Wei Jie
Published: February 2010

This work focused on the different kinetic behaviors in photodimerization between a low‐molecular‐weight molecule and a macromolecule, and the relationship between photodimerization and photo free radical polymerization. We have synthesized two monomers, one (M1) containing a cinnamoyl moiety and another (M2) containing both a cinnamoyl moiety and an acrylate moiety. Their chemical structures were confirmed by FTIR and 1H‐NMR spectral analysis. Polymer (P2) was obtained by free radical polymerization of acrylate moieties of M2. Real‐time FTIR (RT‐FTIR) was used to analyze the kinetic effects of photoreaction. The results strongly suggest that cinnamoyl moieties did not undergo free radical polymerization under exposure of ultraviolet (UV) light. Additionally, the photodimerization of M1 and P2 has been confirmed by RT‐FTIR spectra, UV absorption, and transmittance spectra; and photodimerization of M1 was also confirmed by solid‐state NMR spectra. The results show that this photoreaction of M1 is much faster than that of M2 and P2. Wide angle X‐ray diffraction patterns have demonstrated their different molecular arrangements, which may be responsible for the difference in photodimerization reaction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Rheological, mechanical, optical, and transport properties of blown films of polyamide 6/residual monomer/montmorillonite nanocomposites
Authors: Beatrice Cesar A. G. , Branciforti Marcia C. , Alves Rosa M. V. , Bretas Rosario E. S.
Published: February 2010

Exfoliated nanocomposites of polyamide 6 (PA6) with residual monomer and an organically treated montmorillonite (3 and 5 wt %) were produced by twin‐screw extrusion. The composites had their steady state, dynamic, and transient rheological properties measured by parallel‐plates rheometry; their exfoliation level was characterized by wide angle X‐rays diffraction (WAXD) and transmission electron microscopy (TEM). The characterization showed as follows: (i) the nanoclay's lamellas were well dispersed and distributed thru the PA6, (ii) the postpolymerization of the residual monomer produced more branched chains than linear ones in the pure PA6, (iii) the nanoclay's lamellas acted as entanglement points in the nanocomposites, and (iv) the molecular weight of the PA6 in the nanocomposites decreased. Blown films of the nanocomposites were produced by single screw extrusion; the die pressure during the film blowing of the nanocomposites strongly decreased. The tensile mechanical properties of the blown films were also measured. Along the machine direction (MD), the best mechanical properties were obtained with the 5 wt % nanocomposite, whereas along the transverse direction (TD), the 3 wt % nanocomposite had the best behavior. The glass transition temperature (Tg) of the blown films was measured by dynamic mechanical thermal analyses (DMTA). The 5 wt % nanocomposite had the highest Tg of all the films. The optical properties were measured by spectrophotometry; the nanoclay decreased the films' haze, but the level of transmittance was not affected. The water vapor and oxygen permeability rates of the nanocomposites films were found to be lower than in the pure PA6 blown film as a result of a tortuosity effect. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Flocculation by cationic polyelectrolytes: Relating efficiency with polyelectrolyte characteristics
Authors: Rasteiro M. G. , Garcia F. A. P. , Ferreira P. J. , Antunes E. , Hunkeler D. , Wandrey C.
Published: February 2010

A series of acrylamide/dimethylaminoethylacrylate methyl chloride copolymers (AM‐co‐DMAEA) was evaluated as flocculants for model Precipitated Calcium Carbonate (PCC) in distilled water. These cationic polyelectrolytes (PEL) differed by their AM/DMAEA ratio, i.e., their charge density, chain architecture (linear and branched), their intrinsic viscosity (IV), and zeta potential of their aqueous solutions. The IV being directly related to the hydrodynamic volume of the PEL and the zeta potential reflecting the effective charges in suspension were selected for practically useful correlations with flocculation performance. The fractal dimension (dF) and the scattering exponent (SE) of the flocs, analyzed by the laser diffraction method, were taken as indication of primary particle and aggregate assembly. For the optimum PEL dosage, SE anddFvaried with the IV and zeta potential. It was observable that floc size, floc resistance, and floc reorganization correlate with the PEL characteristics. Copolymers with lower IV, which is here associated with PEL of similar molar mass but lower charge density, yielded larger and less resistant flocs. Copolymers with higher IV originated smaller more compact flocs being more resistant. In high shear situations, where floc breakage should be avoided, as it is the case in papermaking, polymers with high IV yielding large SE are advantageous. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Controllable surface modifications of polyamide by photo‐induced graft polymerization using immobilized photo‐initiators
Authors: Liu Ning , Sun Gang , Gaan Sabyasachi , Rupper Patrick
Published: February 2010

A novel two‐step UV initiated grafting method has been developed and applied on surface modification of polyamide. Anthraquinone‐2‐sulfonate sodium, an acid dye, was chosen as the photo‐initiator. In the first step, photo‐initiators were ionically bonded onto polyamide through a normal acid dye dyeing process. Vinyl monomers such as acrylic acid were then grafted onto polyamide surface in the following step. During UVA irradiation, not only monomers were grafted onto polymer surface, photo‐initiator itself was also covalently bonded onto polymer. The grafted polymers were characterized by Fourier transform infrared spectrometer (FTIR), X‐ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM).The degree of photo‐grafting can be controlled by adjusting concentrations of photo‐initiator and monomer, as well as UVA exposure time. This process demonstrated the feasibility of efficiently modifying polymer surface under low UV intensity. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of hydroxyvalerate composition of polyhydroxy butyrate valerate (PHBV) copolymer on bone cell viability and in vitro degradation
Authors: Liu Hui , Pancholi M. , Stubbs J. , Raghavan D.
Published: February 2010

The objective of this study was to elucidate the role of hydroxyvalerate (HV) composition in polyhydroxy butyrate valerate (PHBV) copolymer film on the degradation of copolymer and osteoblastic cell activity. Degradation was studied by monitoring time‐dependent changes in mass and chemical composition of the macroporous films. The mass loss of PHBV film upon 19 weeks of exposure to pH 7.4 phosphate buffer medium was found to range from 2.8% to 9.2% with a strong dependence on the original composition of the copolyester film and morphology. Tapping mode atomic force microscopy (TMAFM) was used to examine the roughness change of polyester films due to exposure to buffer medium. Chemical analysis of the degraded film was carried out using NMR to aid in the interpretation of the mass loss and TMAFM data. The NMR results showed a significant decrease in the mol % of HV content in the degraded PHBV film. Additionally, we established that UMR‐106 cell proliferation on macroporous PHBV matrix is minimally enhanced by the HV content of PHBV copolymer. Information provided by this study can be used in the selection of appropriate PHBV copolymer for clinical use where the biopolymer needs to remain physically intact and chemically unchanged during the intended period of biomedical application. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Experimental studies on electro‐conductive fabric prepared by in situ polymerization of thiophene onto polyester
Authors: Das Dipayan , Sen Kushal , Saraogi Aditya , Maity Syamal
Published: February 2010

This work deals with development, characterization, and performance of an electro‐conductive fabric prepared by in situ polymerization of thiophene onto polyester. An attempt was made to optimize the polymerization process to achieve highest level of electro‐conductivity of this fabric. The essential characteristics of this electro‐conductive fabric were examined and its electromagnetic shielding performance was evaluated. Polythiophene powder was also synthesized and analyzed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of electric field interference on double nozzles electrospinning
Authors: Yang Enlong , Shi Jingjing , Xue Yuan
Published: February 2010

The low production rate of electrospinning process may limit the industrial use of single needle system. To meet high yield requirement and uniform fibers, a bottom‐up multiple jets electrospinning nozzle was designed, each nozzle can emit 6–18 jets. The influence of electric field interference on jet path, membrane shape, and fiber morphology were investigated. Experiment finds that electrical field strength in the closer part of two nozzles is weakened because of electric field interference when the distance between two nozzles is 30 mm, making the jet hard to emit in this section, and closer part of electrospun fiber webs has fewer fibers. The spinning in far side part of two nozzles is similar to that of single nozzle. While in middle part of one nozzle, the jet path is short, elongation of jets smaller, the formed fibers thicker, solvent evaporation less sufficient. When the distance of two nozzles is increased to 50 mm, influence of electric field interference is weaker, the electrospun fiber web and average diameter of fibers are almost the same as that of single nozzle electrospinning. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structural characterization and antimicrobial activity of chitosan (CS‐40)/nisin complexes
Authors: Cai Jun , Yang Jianhong , Wang Changgao , Hu Ying , Lin Jianguo , Fan Lihong
Published: February 2010

A complex of chitosan (CS‐40) and nisin (CS‐40/nisin) was prepared and characterized with Fourier transform infrared spectroscopy and thermal analysis (thermogravimetry, differential thermogravimetry, and differential scanning calorimetry). The results show that the complex formed mainly by electrostatic interaction between the protonated amino group in CS‐40 backbone with the carboxylate ion of nisin. Minimum inhibitory concentrations (MICs) were evaluated against Gram‐positive bacteria (Staphylococcus aureus, Bacillus subtilis, and Bacillus stearothermophilus), Gram‐negative bacteria (Escherichia coli, Salmonella enteritidis, and Proteus vulgaris), and fungi (Fusarium oxysporum). The results show that the CS‐40/nisin solution did inhibit or even more strongly inhibited the growth of all the tested microorganisms, whereas CS‐40 did not inhibit the growth of F. oxysporum and nisin did not inhibit the growth of Gram‐negative bacteria (E. coli, S. enteritidis, and P. vulgaris). The relative inhibition times of CS‐40/nisin solutions with different concentrations and ratios of CS‐40 and nisin were also investigated against the seven microorganisms. The results showed that CS‐40/nisin solutions with CS‐40/nisin concentration ratios of 0.05/0.005, 0.05/0.0025, 0.05/0.00125, and 0.025/0.0001% had higher antimicrobial activity against all tested bacteria and fungi. The relationship between complex formation and antimicrobial activity is discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Fabrication of continuous aligned polyvinylpyrrolidone fibers via electrospinning by elimination of the jet bending instability
Authors: Cui Xiaojie , Li Luming , Xu Jun , Xu Fu
Published: February 2010

In this study, we successfully fabricated highly aligned polyvinylpyrrolidone (PVP) fibers and crossed mats by restraining and eliminating the jet bending instability through a dual‐opposite‐spinnerets electrospinning (DOSES) method. The DOSES process was photographed by a digital camera, and the morphology of the fibers was analyzed with field emission scanning electron microscopy. We argue that the elimination of the jet whipping and bending instability was achieved by adjusting the concentration of the polymer solution. When the concentration of PVP solution was raised to more than 15 wt %, two individual fibers stuck together were obtained without the appearance of the jet bending instability at a suitable take‐up velocity. This study demonstrated solid improvement in both the alignment of the polymer yarns and the fabrication of individual fibers side by side. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Polymer‐coated piezoelectric quartz crystal sensor for sensing the nerve agent simulant dimethyl methylphosphonate vapor
Authors: Maji S. , Asrey R. , Kumar S. , Saxena C. , Kumar N. , Vyas K. D. , Banerjee S.
Published: February 2010

A chemical vapor sensor based on a quartz crystal microbalance was fabricated with a 10‐MHz quartz crystal oscillator. The quartz crystals were coated with four newly synthesized polymers and were studied for the detection of the nerve agent simulant dimethyl methylphosphonate vapor. The sensor was tested for immediate and extended periods of time. Various sensing parameters (e.g., the sensitivity, response time, and recovery time) were evaluated with respect to different coating materials. All the polymers showed fairly good baseline stability even after several cycles. The highest frequency drift of 23.8 Hz/kHz was observed for one of the polymers, whereas another polymer showed the best sensing stability over an extended period of 250 days. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Reduction of postsurgical adhesion formation with CM‐chitosan hydrogel barriers prepared by using γ‐irradiation
Authors: Gwon Hui‐Jeong , Lim Youn‐Mook , Chang Ho‐Nam , Nho Young‐Chang
Published: February 2010

To evaluate the efficiency of carboxymethylchitosan (CM‐chitosan)‐based hydrogels as barriers for reducing postsurgical adhesions, CM‐chitosan was synthesized to simplify the hydrogel‐making process, and the CM‐chitosan solutions were cross‐linked by using γ‐ray irradiation to create the desired hydrogels instead of using chemical cross‐linking reagents. The prepared CM‐chitosan hydrogels were characterized by a FTIR spectroscopy, swelling behavior, gel‐fraction content,and mechanical property such as gel strength of a hydrogel and the results showed a good swelling behavior and mechanical properties. Also, the radiation‐induced CM‐chitosan hydrogels significantly reduced and inhibited the postsurgical adhesions in the rat models. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Induction of CD44 cleavage in articular chondrocytes
Authors: Takahashi Nobunori , Knudson Cheryl B. , Thankamony Sai , Ariyoshi Wataru , Mellor Liliana , Im Hee‐Jeong , Knudson Warren
Published: February 2010

Objective

The hyaluronan receptor CD44 provides chondrocytes with a mechanism for sensing and responding to changes in the extracellular matrix. The purpose of this study was to document the fragmentation and loss of CD44 and to determine the likely mechanisms involved.

Methods

A polyclonal anti‐CD44 cytotail antibody was generated to detect CD44 fragmentation by Western blot analysis. Chondrocytes were isolated from human or bovine articular cartilage. Primary articular chondrocytes were treated with interleukin‐1β (IL‐1β), hyaluronan oligosaccharides, or phorbol myristate acetate or were passaged and subcultured in monolayer to induce dedifferentiation. Conditions that altered the capacity of CD44 to transit into lipid rafts, or pharmacologic inhibitors of metalloproteinase or γ‐secretase activity were used to define the mechanism of fragmentation of CD44.

Results

Chondrocytes from osteoarthritic cartilage exhibited CD44 fragmentation as low molecular mass bands, corresponding to the CD44‐EXT and CD44‐ICD bands. Following dedifferentiation of chondrocytes or treatment of primary chondrocytes with hyaluronan oligosaccharides, IL‐1β, or phorbol myristate acetate, CD44 fragmentation was enhanced. Subsequent culture of the dedifferentiated chondrocytes in 3‐dimensional alginate beads rescued the chondrocyte phenotype and diminished the fragmentation of CD44. Fragmentation of CD44 in chondrocytes was blocked in the presence of the metalloproteinase inhibitor GM6001 and the γ‐secretase inhibitor DAPT.

Conclusion

CD44 fragmentation, consistent with a signature pattern reported for sequential metalloproteinase/γ‐secretase cleavage of CD44, is a common metabolic feature of chondrocytes that have undergone dedifferentiation in vitro and osteoarthritic chondrocytes. Transit of CD44 into lipid rafts may be required for its fragmentation.
Synovial tissue heterogeneity in rheumatoid arthritis in relation to disease activity and biomarkers in peripheral blood
Authors: van Baarsen Lisa G. M. , Wijbrandts Carla A. , Timmer Trieneke C. G. , van der Pouw Kraan Tineke C. T. M. , Tak Paul P. , Verweij Cornelis L.
Published: February 2010

Objective

To investigate the clinical relevance of synovial tissue subtypes in rheumatoid arthritis (RA) and to search for peripheral blood (PB) markers that may serve as biomarkers for tissue subtypes.

Methods

Gene expression analysis using complementary DNA microarrays was applied on paired synovial tissue biopsy and PB samples obtained from 17 RA patients. Molecular tissue subtypes were correlated with histologic parameters (CD3, CD22, CD38, CD68, CD163, tumor necrosis factor α, intercellular adhesion molecule 1, vascular cell adhesion molecule, and E‐selectin), disease characteristics, and PB markers. PANTHER classification was used for pathway analysis.

Results

Genomic subtyping of high‐ and low‐inflammation rheumatoid synovial tissues based on gene expression profiles exactly matched immunohistochemical classification. The patients with the high‐inflammation tissue type had higher Disease Activity Scores in 28 joints, higher C‐reactive protein levels, higher erythrocyte sedimentation rates, increased numbers of platelets, and shorter disease durations. Comparative analysis of PB gene expression profiles yielded no statistically significant differences between the 2 tissue groups at the single‐gene expression level. PANTHER pathway analysis revealed a significant association of increased protein biosynthesis with high‐inflammation tissue.

Conclusion

High‐inflammation tissue is associated with more severe disease and shorter disease duration. While pathway‐level analysis revealed that coordinate differential expression of genes involved in protein synthesis in PB is associated with high‐inflammation tissue types, differential tissue pathology was not reflected in the PB by differential expression of single genes.