bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and properties of crystalline dicarboxylated poly(L‐lactic acid) prepolymers
Authors: Sun Xiangying , Wu Linbo
Published: April 2011

Crystalline dicarboxylated poly(L‐lactic acid)s (dcPLLAs) with number‐average molecular weights (Mn's) of 103 to 104 g/mol were synthesized via the melt polycondensation of L‐lactic acid (LLA) in the presence of succinic anhydride (SAD), with tin(II) chloride and toluene‐4‐sulfonic acid as binary catalysts. They were characterized by end‐group titration, 1H‐NMR, differential scanning calorimetry, and wide‐angle X‐ray diffraction. The terminal COOH percentage reached over 98%, and the molecular weight could be controlled by the molar ratio of LLA to SAD. The thermal behaviors depended on the molecular weight. The poly(L‐lactic acid)s (PLLAs) crystallized slowly for Mn ≤ 2000 but quickly for Mn ≥ 4000. The crystallinity increased from 27 to 40% when Mn grew from 4000 to 10,000. With comparison to ordinary PLLA, the dcPLLA had the same crystallization structure but a slightly lower crystallizability. The glass‐transition temperature was clearly higher than that of amorphous dcPLLAs. With a controllable molecular weight, high COOH percentage, and crystallinity, the dcPLLA with Mn ≥ 4000 appeared to be a suitable prepolymer for the preparation of high‐molecular‐weight crystalline PLLA via chain extension. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Biodegradable polyurethanes: Comparative study of electrospun scaffolds and films
Authors: Caracciolo Pablo C. , Buffa Fabián , Thomas Vinoy , Vohra Yogesh K. , Abraham Gustavo A.
Published: April 2011

The development of elastomeric, bioresorbable, and biocompatible segmented polyurethanes (SPUs) for use in tissue‐engineering applications has attracted considerable interest in recent years. In this work, nonporous films and microfiber/nanofiber scaffolds, which were prepared from two different poly(ϵ‐caprolactone)‐based SPUs previously synthesized from 1,6‐hexamethylene diisocyanate and novel chain extenders containing urea groups or an aromatic amino acid derivative, were studied. Their thermal properties were influenced by both the different chemical structures of the hard segments and the processing conditions. The mechanical properties of the scaffolds (the elastic modulus, ultimate strain, and tensile stress) were adequate for engineered soft‐tissue constructs (e.g., myocardial tissue). The film samples displayed a low swelling degree (<2 wt %) in a phosphate‐buffered solution at 37°C. The introduction of the amino acid derivative chain extender with hydrolyzable ester bonds contributed to greater degradation. The fibrous scaffolds exhibited higher hydrolytic stability than the films after short assay times because of their more crystalline structures and higher degrees of association by hydrogen bonding, but they also experienced higher mass losses under accelerated conditions (70°C). This suggested that the degradation rate was not constant but depended on the degradation time and the processing technique. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Attaining optimal dyeability and tensile properties of polypropylene/poly(ethylene terephthalate) blends with a special cubic mixture experimental design
Authors: Mirjalili Fereshteh , Moradian Siamak , Ameri Farhad
Published: April 2011

In this investigation, we attempted to enhance the dyeability of polypropylene (PP) with disperse dyestuffs without adversely affecting its tensile properties. To this end, a special cubic experimental design was used to predict the effect of variations in the properties of a tricomponent mixture composed of PP, poly(ethylene terephthalate) (PET), and maleic anhydride grafted polypropylene (PP‐g‐MA) on the dyeability and tensile properties of the resultant polymer blend. The results illustrate that there seemed to be critical PET content, above which the blend's dye uptake tended to remain constant, but the tensile properties were adversely affected. Further analysis of the results indicated that the PP/PET/PP‐g‐MA blends in which the PET and PP‐g‐MA contents were in the range 10–15 and 4–5 wt %, respectively, gave maximal dye uptake and desirable tensile properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Poly(L‐lactide)/polypropylene blends: Evaluation of mechanical, thermal, and morphological characteristics
Authors: Choudhary Priyanka , Mohanty Smita , Nayak Sanjay K. , Unnikrishnan Lakshmi
Published: April 2011

Poly(Llactide) (PLA) was blended with polypropylene (PP) at various ratios (PLA:PP = 90 : 10, 80 : 20, 70 : 30, and 50 : 50) with a melt‐blending technique in an attempt to improve the melt processability of PLA. Maleic anhydride (MAH)‐grafted PP and glycidyl methacrylate were used as the reactive compatibilizers to induce miscibility in the blend. The PLA/PP blend at a blend ratio of 90 : 10, exhibited optimum mechanical performance. Differential scanning calorimetry and thermogravimetric analysis studies showed that the PLA/PP/MAH‐g‐PP blend had the maximum thermal stability with the support of the heat deflection temperature values. Furthermore, dynamic mechanical analysis findings revealed an increase in the glass‐transition temperature and storage modulus with the addition of MAH‐g‐PP compatibilizer. The interaction between the compatibilizers and constituent polymers was confirmed from Fourier transform infrared spectra, and scanning electron microscopy of impact‐fractured samples showed that the soft PP phase was dispersed within the PLA matrix, and a decrease in the domain size of the dispersed phase was observed with the incorporation of MAH‐g‐PP, which acted as a compatibilizer to improve the compatibility between PLA and PP. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Miscibility and thermal behavior of poly(vinyl chloride)/feather keratin blends
Authors: Akhlaghi Shahin , Sharif Alireza , Kalaee Mohammadreza , Manafi Mohammadreza
Published: April 2011

Various poly(vinyl chloride) (PVC)/feather keratin (FK) blends were prepared via a solution blending method in the presence of N,N‐dimethylformamide as a solvent. The miscibility of the blends was studied with different analytical methods, such as dilute solution viscometry, differential scanning calorimetry, refractometry, and atomic force microscopy. According to the results obtained from these techniques, it was concluded that the PVC/FK blend was miscible in all the studied compositions. Specific interactions between carbonyl groups of the FK structure and hydrogen from the chlorine‐containing carbon of the PVC were found to be responsible for the observed miscibility on the basis of Fourier transform infrared spectroscopy. Furthermore, increasing the FK content in the blends resulted in their miscibility enhancement. The thermal stability of the samples, as an important characteristic of biobased polymer blends, was finally examined in terms of their FK weight percentage and application temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis, characterization and use of polymer‐supported phase transfer catalyst in organic reactions
Authors: Kaur Inderjeet , Kumari Vandna , Dhiman Poonam K.
Published: April 2011

A polymer‐supported (PS) phase transfer catalyst, polyethylene‐g‐quaternary ammonium salt (PE‐g‐QN+), is prepared through a three‐step graft copolymerization of maleic anhydride (MAn) onto polyethylene (PE) by photochemical method using 1% benzophenone (Bz) as photosensitizer. Post grafted acid hydrolysis of polyethylene‐g‐maleic anhydride (PE‐g‐MAn) results in the preparation of PE‐g‐succinic acid which on further treatment with tetrabutylammonium bromide (TBAB) under basic conditions in tetrahydrofuran (THF) gives PE‐g‐QN+. Optimum conditions pertaining to maximum percentage of grafting have been evaluated as a function of concentration of maleic anhydride, amount of photosensitizer, and time of reaction. Maximum percentage of grafting (25%) was obtained using 3.57 mol of MAn and 0.5 mL of 1% Bz in 120 min. The PE and graft copolymers, PE‐g‐MAn, and PE‐g‐QN+ were characterized by FTIR Spectroscopy and thermogravimetric analysis (TGA). The ionic nature of quaternary ammonium salt, PE‐g‐QN+ has also been confirmed by conductance measurements. PE‐g‐QN+ reagent have been used successfully for polymerization, amidation, and esterification reactions. The products obtained were characterized by FTIR and H1NMR spectral methods. The reagent was reused for the further reactions and it was observed that the polymeric reagent polymerize, amidate, and esterificate the compounds successfully but with little lower product yield. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effects of the structural components on slow crack growth process in polyethylene blends. Composition intervals prediction for pipe applications
Authors: García Rafael A. , Carrero A. , Martín C. , Domínguez C.
Published: April 2011

A linear low density polyethylene (LLDPE) obtained from a metallocene based catalyst, was blended in an extruder with a high density polyethylene (HDPE) homopolymer synthesized with an iron based catalyst. The bimodal polyethylenes, made with blends from 0 to 100 wt % of copolymer were characterized by SEC, DSC, ESEM, SEC‐FTIR, and TREF, while their resistance to the slow crack growth (SCG) was evaluated through the PENT test. Results provide that polymer blends with copolymer contents between 47.5 and 72.5 wt % are suitable for pipe applications. Furthermore, a method based on the intercrystalline tie chains calculus is proposed as suitable and attractive, because of its simplicity and novelty, to forecast long term performance and to predict capabilities. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
DSC study of foamable poly (vinyl chloride‐co‐vinyl acetate) plastisols of different commercial plasticizers
Authors: Zoller Agnes , Marcilla Antonio
Published: April 2011

In this article the characterization of the thermal behavior of foamable PVC (Poly (vinyl chloride)) plastisols from 20 different plasticizers has been studied by differential scanning calorimetry (DSC). The interactions between the resin and the plasticizer as well as the decomposition of the azodicarbonamide (ADC)—the chemical blowing agent (CBA) used—have been analyzed. The latter process is of crucial importance for the knowledge of plasticized PVC flexible foam formation. Clear effects of the chemical nature of the plasticizers and their molecular weight (Mw) have been observed, both in the interactions (swelling and early stages of gelation) between the resin and the plasticizer, as well as in the temperature of the ADC decomposition and the shape of the DSC peak. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A novel polycaprolactone‐grafted‐carbon black nanocomposite‐based sensor for detecting solvent vapors
Authors: Cheng Jianguo , Wang Li , Huo Jia , Yu Haojie
Published: April 2011

A novel vapor sensor is fabricated with polycaprolactone‐grafted‐carbon black (CB‐g‐PCL) as sensing materials. The influence of PCL with different grafting contents and solvents with various solubility and concentrations including benzene, deionized water, epoxy chloropropane (ECP), ethanol, toluene, and tetrahydrofuran on the response of electric resistance was investigated. When compared with mixture of PCL and carbon black, the CB‐g‐PCL‐based sensor shows high sensitivity and good reproducibility. Sensor with moderate content of grafting PCL showed high sensitivity to vapors. The electric resistance of sensor drastically increased in ECP, ethanol, and deionized water with similar solubility with PCL and showed slight increase in benzene, toluene, and tetrahydrofuran with different solubility. The study on the response of electric resistance of CB‐g‐PCL to different vapors confirmed the swelling‐induced sensing mechanism of sensor based on polymer‐grafted‐conductive nanomaterials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Proton conducting crosslinked polymer electrolyte membranes based on SBS block copolymer
Authors: Roh Dong Kyu , Koh Jong Kwan , Chi Won Seok , Shul Yong Gun , Kim Jong Hak
Published: April 2011

A series of crosslinked polymer electrolyte membranes with controlled structures were prepared based on poly(styrene‐b‐butadiene‐b‐styrene) (SBS) triblock copolymer and a sulfonated monomer, 2‐sulfoethyl methacrylate (SEMA). SBS membranes were thermally crosslinked with SEMA in the presence of a thermal‐initiator, 4,4′‐azobis(4‐cyanovaleric acid) (ACVA), as confirmed by FT‐IR spectroscopy. The water uptake and ion exchange capacity (IEC) of membranes increased almost linearly with SEMA concentrations due to the increase of SO groups. However, the proton conductivity of membranes increased linearly up to 33 wt % of SEMA, above which it abruptly jumped to 0.04 S/cm presumably due to the formation of well‐developed proton channels. Microphase‐separated morphology and amorphous structures of crosslinked SBS/SEMA membranes were observed using wide angle X‐ray scattering (WAXS), small angle X‐ray scattering (SAXS), and transmission electron microscopy (TEM). The membranes exhibited good mechanical properties and high thermal stability up to 250°C, as determined by a universal testing machine (UTM) and thermal gravimetric analysis (TGA), respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Structural parameters in relation to the rheological behavior and properties of PP/EPR in‐reactor alloy synthesized by multi‐stage sequential polymerization
Authors: Bagheri H. , Nekoomanesh M. , Hakim S. , Jahani Y. , Fan Z. Q.
Published: April 2011

The morphology and molecular structure of an in‐reactor polypropylene/ethylene propylene rubber alloy, synthesized by multi‐stage sequential polymerization, were studied with respect to the rheological behavior and final properties of the alloy. The polymer alloys, based on different structural morphologies, were characterized by SEM, GPC, 13C NMR, DSC, rheological analysis, and mechanical testing. The scanning electron microscopy of samples showed that the size of the dispersed phase particles is decreased as the switch frequency of copolymerization timing is increased. The GPC results showed that switch frequency slightly altered the molecular weight distribution of the copolymer although it had no effect on PP homopolymer. 13C NMR results were used for the evaluation of compatibility between the two phases with changes in switch frequency. DSC results showed that Tm and Tc were almost independent of switch frequency, even though the size of dispersed phase was decreased and the blend crystal content increased with ΔH of about 13%. The small amplitude oscillation rheometry showed that storage modulus and viscosity shifted to higher values when switch frequency increased. In studying the mechanical properties it was revealed that, especially the impact strength increased by about 62% when the size of the dispersed particles was decreased. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Comparison of the toughening effects of different elastomers on nylon 1010
Authors: Yu Haiyang , Zhang Yong , Ren Wentan , Hoch Martin , Guo Sharon
Published: April 2011

The toughness of three different elastomer‐toughened nylon 1010 blends was investigated via standard notched Izod impact test and single edge notched three‐point bending test. The toughness of nylon 1010 blends varies much with different elastomer types and components. All three kinds of nylon/elastomer/maleated‐elastomer blends showed high impact strength (over 50 kJ m−2) as long as at appropriate blending ratios. With increasing maleated elastomer content, brittle‐ductile transition was observed for all three kinds of elastomer‐toughened nylon 1010 blends. The number average dispersed particle size (dn) of ethylene‐1‐octene copolymers or ethylene‐vinyl acetate copolymers toughened nylon 1010 blends significantly decreased from over 1 to 0.1 μm with increasing corresponding maleated elastomer content. Investigation on the fracture toughness showed the dissipative energy density gradually increased with decreasing dn, while the limited specific fracture energy increased with increasing dn when dn was below 1 μm and then sharply decreased with further increasing dn. The energy consumed in the outer plastic zone was the main part of the whole energy dissipated during the fracture process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Enhancing protein resistance of hydrogels based on poly(2‐hydroxyethyl methacrylate) and poly(2‐methacryloyloxyethyl phosphorylcholine) with interpenetrating network structure
Authors: Wang Jingjing , Li Xinsong
Published: April 2011

In this work, sequential interpenetrating polymer networks (IPNs) based on poly(2‐hydroxyethyl methacrylate) (PHEMA) and poly (2‐methacryloyloxyethyl phosphorylcholine) (PMPC) were prepared with improved protein resistance. The bulk properties of the IPN hydrogels such as water content, ion permeability and mechanical strength were determined by the gravimetric method, ionoflux measurement technique and tensile tester respectively. The surface characteristics of the IPNs were investigated by X‐ray photoelectron spectroscopy (XPS) and contact angle measurements. XPS analysis suggested that PMPC was present on the surface and in the bulk material. The IPN hydrogels possessed more hydrophilic surface than PHEMA revealed by contact angle measurements. Bovine serum albumin was used as a model protein to evaluate protein resistance by bicinchoninic acid assay method. The result revealed that the protein adsorption on the IPNs showed dramatically reduction compared to PHEMA. These results suggest that the IPNs based on PHEMA and PMPC may be further developed as ophthalmic biomaterials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of the nucleation mechanism on complex poly(L‐lactide) nonisothermal crystallization process. Part 1: Thermal and structural characterization
Authors: Martinelli Andrea , Calì Massimo , D'Ilario Lucio , Francolini Iolanda , Piozzi Antonella
Published: April 2011

The effect of the holding temperature and time in the melt state of poly(L‐lactide) (PLLA) samples on the nonisothermal melt crystallization process and on the structure have been investigated by means of DSC, polarized optical microscopy and wide angle X‐ray scattering. As standard starting material, single crystals grown from dilute solution were used. In the mild melting condition, the survived athermal nuclei favor high temperature polymer crystallization, while the more severe treatment leads the PLLA to crystallize at higher supercooling with a sporadic nucleation. At the intermediate melting temperature a distinct double nucleation mechanism was observed while at the lower nuclei concentration, a double crystallization rate was also found. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Electrical conductivity of single walled and multiwalled carbon nanotube containing wool fibers
Authors: Montazer Majid , Ghayem Asghari Mohammad Samin , Pakdel Esfandiar
Published: April 2011

The main purpose of this study was producing conductive wool fabric applying carbon nanotubes. Raw and oxidized wool samples were treated with carbon nanotubes in the impregnating bath in the presence of citric acid as a crosslinking agent and sodium hypophosphite as a catalyst while sonicating them in the ultrasonic bath. Electrical resistance, washing durability, and color variation of treated samples were assessed. Through SEM images, the surface morphology of treated samples was studied confirming the surface coating through carbon nanotubes. According to the results, the electrical resistance of treated wool with carbon nanotubes reduced substantially. However, the single‐walled carbon nanotubes are more useful to increase the conductivity. In addition, the wool color changed into gray after the treatment. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Use of isothermal and nonisothermal chemiluminescence measurements for comparison of stabilizing efficiency of hydroxytyrosol (3,4‐dihydroxy‐phenylethanol), α‐tocopherol and irganox®1076 in polypropylene
Authors: Peltzer M. , Jiménez A. , Matisová‐Rychlá L. , Rychlý J.
Published: April 2011

Hydroxytyrosol (3,4‐dihydroxyphenylethanol) is a phenolic compound obtained during olive processing in oil manufacturing. It plays a role in enhancing the oxidative stability of olive oil with positive effects on human health. The raising interest towards the use of natural antioxidants as stabilizers in polymer formulations makes hydroxytyrosol a potential candidate to substitute synthetic antioxidants in polyolefin formulations. In this study, hydroxytyrosol was compared in antioxidant efficiency with two other compounds, one of them obtained from natural resources (α‐tocopherol) and a synthetic commercial phenolic antioxidant (Irganox®1076). Chemiluminescence was used to as a tool to assess the increase in the polypropylene stability to thermo‐oxidative degradation. A significant increase in the value of oxygen induction time with the initial concentration of natural antioxidants tested under isothermal conditions at 140, 150 and 160°C was observed. A comparison at the same concentration level (0.1 wt %) between the three antioxidants showed an order of stabilizing efficiency as: α‐tocopherol > Irganox®1076 > hydroxytyrosol, but all them showed clearly their stabilization performance in polypropylene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and characterization of high melt strength polypropylene with long chain branched structure by the reactive extrusion process
Authors: Cao Kun , Li Yan , Lu Zhan‐Quan , Wu Shui‐Liang , Chen Zhen‐Hua , Yao Zhen , Huang Zhi‐Ming
Published: April 2011

The reactive extrusion of maleic anhydride grafted polypropylene (PP‐g‐MAH) with ethylenediamine (EDA) as coupling agent is carried out in a corotating twin‐screw extruder to produce long chain branched polypropylene (LCBPP). Part of PP‐g‐MAH is replaced by maleic anhydride grafted high‐density polyethylene (HDPE‐g‐MAH) or linear low‐density polyethylene (LLDPE‐g‐MAH) to obtain hybrid long chain branched (LCB) polyolefins. Compared with the PP‐g‐MAH, PE‐g‐MAH, and their blends, the LCB polyolefins exhibit excellent dynamic shear and transient extensional rheological characteristics such as increased dynamic modulus, higher low‐frequency complex viscosity, broader relaxation spectra, significantly enhanced melt strength and strain‐hardening behaviors. The LCB polyolefins also have higher tensile strength, tensile modulus, impact strength and lower elongation at break than their blends. Furthermore, supercritical carbon dioxide (scCO2) is constructively introduced in the reactive extrusion process. In the presence of scCO2, the motor current of the twin extruder is decreased and LCB polyolefins with lower melt flow rate (MFR), higher complex viscosity and increased tensile strength and modulus can be obtained. This indicates that the application of scCO2 can reduce the viscosity of melt in extruder, enhance the diffusion of reactive species, and then facilitate the long chain branching reaction between anhydride group and primary amine group. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Sclerostin antibody treatment enhances bone strength but does not prevent growth retardation in young mice treated with dexamethasone
Authors: Marenzana M. , Greenslade K. , Eddleston A. , Okoye R. , Marshall D. , Moore A. , Robinson M. K.
Published: April 2011

Objective

Exposure to supraphysiologic levels of glucocorticoid drugs is known to have detrimental effects on bone formation and linear growth. Patients with sclerosteosis lack the bone regulatory protein sclerostin, have excessive bone formation, and are typically above average in height. This study was undertaken to characterize the effects of a monoclonal antibody to sclerostin (Scl‐AbI) in mice exposed to dexamethasone (DEX).

Methods

Young mice were concomitantly treated with DEX (or vehicle control) and Scl‐AbI antibody (or isotype‐matched control antibody [Ctrl‐Ab]) in 2 independent studies. Linear growth, the volume and strength of the bones, and the levels of bone turnover markers were analyzed.

Results

In DEX‐treated mice, Scl‐AbI had no significant effect on linear growth when compared to control treatment (Ctrl‐Ab). However, in mice treated with DEX and Scl‐ABI, a significant increase in trabecular bone at the femoral metaphysis (bone volume/total volume +117% versus Ctrl‐Ab–treated mice) and in the width and volume of the cortical bone at the femoral diaphysis (+24% and +20%, respectively, versus Ctrl‐Ab–treated mice) was noted. Scl‐AbI treatment also improved mechanical strength (as assessed by 4‐point bending studies) at the femoral diaphysis in DEX‐treated mice (maximum load +60% and ultimate strength +47% in Scl‐AbI–treated mice versus Ctrl‐Ab–treated mice). Elevated osteocalcin levels were not detected in DEX‐treated mice that received Scl‐AbI, although levels of type 5b tartrate‐resistant acid phosphatase were significantly lower than those observed in mice receiving DEX and Ctrl‐Ab.

Conclusion

Scl‐AbI treatment does not prevent the detrimental effects of DEX on linear growth, but the antibody does increase both cortical and trabecular bone and improves bone mechanical properties in DEX‐treated mice.
Role of semaphorin 7a signaling in transforming growth factor β1–induced lung fibrosis and scleroderma‐related interstitial lung disease
Authors: Gan Ye , Reilkoff Ronald , Peng Xueyan , Russell Thomas , Chen Qingsheng , Mathai Susan K. , Homer Robert , Gulati Mridu , Siner Jonathan , Elias Jack , Bucala Richard , Herzog Erica
Published: April 2011

Objective

Semaphorin 7a regulates transforming growth factor β1 (TGFβ1)–induced fibrosis. This study was undertaken to test the hypothesis that semaphorin 7a exerts its profibrotic effects in part by promoting the tissue accumulation of CD45+ fibrocytes.

Methods

A murine model of pulmonary fibrosis in which an inducible, bioactive form of the human TGFβ1 gene is overexpressed in the lung was used. Fibrosis and fibrocytes were evaluated in TGFβ1‐transgenic mice in which the semaphorin 7a locus had been disrupted. The effect of replacement or deletion of semaphorin 7a on bone marrow–derived cells was ascertained using bone marrow transplantation. The role of the semaphorin 7a receptor β1 integrin was assessed using neutralizing antibodies. The applicability of these findings to TGFβ1‐driven fibrosis in humans was examined in patients with scleroderma‐related interstitial lung disease (ILD).

Results

The appearance of fibrocytes in the lungs of TGFβ1‐transgenic mice required semaphorin 7a. Replacement of semaphorin 7a on bone marrow–derived cells restored lung fibrosis and fibrocytes. Immunoneutralization of β1 integrin reduced pulmonary fibrocytes and fibrosis. Peripheral blood mononuclear cells (PBMCs) from patients with scleroderma‐related ILD showed increased levels of messenger RNA for semaphorin 7a and its receptors, with semaphorin 7a located on collagen‐producing fibrocytes and CD19+ lymphocytes. Peripheral blood fibrocyte outgrowth was enhanced in these patients. Stimulation of normal human PBMCs with recombinant semaphorin 7a enhanced fibrocyte differentiation; these effects were attenuated by β1 integrin neutralization.

Conclusion

Our findings indicate that interventions that reduce semaphorin 7a expression or prevent the semaphorin 7a–β1 integrin interaction may ameliorate TGFβ1‐driven or fibrocyte‐associated autoimmune fibroses.
Dose escalation of certolizumab pegol from 200 mg to 400 mg every other week provides no additional efficacy in rheumatoid arthritis: An analysis of individual patient‐level data
Authors: Curtis Jeffrey R. , Chen L. , Luijtens K. , Navarro‐Millan I. , Goel N. , Gervitz L. , Weinblatt M.
Published: April 2011

Objective

To determine whether certolizumab pegol (CZP) dosage escalation from 200 mg to 400 mg every other week benefits some patients with rheumatoid arthritis (RA).

Methods

In the extension of the Rheumatoid Arthritis Prevention of Structural Damage 1 (RAPID 1) study into an open‐label study, all patients received CZP 400 mg every other week in combination with methotrexate (MTX). Before the open‐label phase of the study, patients had received CZP 200 mg or 400 mg every other week, or placebo every other week, as add‐on therapy to MTX. The open‐label study included those who had completed the RAPID 1 study (to week 52) and also those who had been withdrawn from the study (at week 16, due to inadequate response). At 12 weeks and 48 weeks after enrollment in the open‐label study, changes in the Disease Activity Score in 28 joints (DAS28) were compared in dose‐escalation patients (200 mg increased to 400 mg every other week) versus stable‐dosage patients (400 mg every other week), using cumulative probability plots of individual patient‐level data.

Results

In the group of patients who had completed the RAPID 1 study and had moderate or severe disease activity at entry into the open‐label study, and in those who had been withdrawn early from the RAPID 1 study, the median DAS28 improvements 12 weeks after enrollment into the open‐label study were similar in the dose‐escalation and stable‐dose groups. Individual patient‐level data revealed no greater likelihood of response in the group of patients who received an increased dosage of CZP versus those in whom a stable dosage was maintained, whether they had completed the RAPID 1 study or had been withdrawn early.

Conclusion

Although patient heterogeneity in clinical settings is acknowledged, the present results indicate that increasing the dose of CZP from 200 mg to 400 mg offers little additional benefit in RA, even for selected patients.
Oral administration of artemisinin analog SM934 ameliorates lupus syndromes in MRL/lpr mice by inhibiting Th1 and Th17 cell responses
Authors: Hou Li‐Fei , He Shi‐Jun , Li Xin , Yang Yang , He Pei‐Lan , Zhou Yu , Zhu Feng‐Hua , Yang Yi‐Fu , Li Ying , Tang Wei , Zuo Jian‐Ping
Published: April 2011

Objective

SM934, an artemisinin derivative, possesses potent antiproliferative and antiinflammatory properties. The aim of this study was to examine the effects and explore the mechanisms of SM934 to treat autoimmune disease in lupus‐prone female MRL/lpr mice.

Methods

In vitro, the effects of SM934 on the activation of polyclonal CD4+ T cells and the differentiation of naive CD4+ T cells were examined. In vivo, the preventative or therapeutic effects of SM934 in MRL/lpr mice were investigated. Ex vivo, the mechanisms of treatment were explored according to the immunologic correlates of disease.

Results

In vitro, SM934 inhibited interferon‐γ (IFNγ) and interleukin‐17 (IL‐17) production from polyclonal CD4+ T cells activated by T cell receptor engagement and the differentiation of naive CD4+ T cells into Th1 and Th17 cells, but not Treg cells. In vivo, 12‐week‐old MRL/lpr mice treated with SM934 for 4 weeks showed significantly ameliorated proteinuria and renal lesion severity; decreased levels of blood urea nitrogen, serum IFNγ, and serum anti–double‐stranded DNA antibodies; decreased spleen size; and a lower percentage of CD3+B220+CD4−CD8− T cells; 16‐week‐old MRL/lpr mice treated with SM934 for 8 weeks avoided severe proteinuria and survived longer. Ex vivo, SM934 treatment elevated the percentage of Treg cells, inhibited the development of Th1 and Th17 cells, and impeded the comprehensive activation of STAT‐1, STAT‐3, and STAT‐5 proteins in splenocytes.

Conclusion

Taken together, the results of this study demonstrated that the artemisinin analog SM934 had therapeutic effects in lupus‐prone female MRL/lpr mice by inhibiting both Th1 cell and Th17 cell responses. Moreover, this study indicated that both IFNγ and IL‐17 are required for the elicitation and development of murine lupus.
Solid malignancies among etanercept‐treated patients with granulomatosis with polyangiitis (Wegener's): Long‐term followup of a multicenter longitudinal cohort
Authors: Silva Francisco , Seo Philip , Schroeder Darrell R. , Stone John H. , Merkel Peter A. , Hoffman Gary S. , Spiera Robert , Sebastian Jodi K. , Davis John C. , St.Clair E. William , Allen Nancy B. , McCune W. Joseph , Ytterberg Steven R. , Specks Ulrich ,   Wegener's Granulomatosis Etanercept Trial Research Group
Published: April 2011

Objective

An association between therapeutic inhibition of tumor necrosis factor (TNF) and solid malignancies was observed during the Wegener's Granulomatosis Etanercept Trial (WGET), which included 180 patients with granulomatosis with polyangiitis (Wegener's) (GPA). The present study was conducted to determine the malignancy risk beyond the time of exposure to study therapy.

Methods

The occurrence and type of solid malignancies were ascertained using a standardized data form. Data collected included vital status, histologic findings, and therapeutic interventions. The Surveillance, Epidemiology, and End‐Results database was used to estimate a standardized incidence rate (SIR) for solid malignancies.

Results

Post‐trial followup data were available for 153 patients (85% of the original cohort), with a median followup time of 43 months. Fifty percent of these patients had received etanercept. There were no differences in demographic characteristics between the etanercept and placebo groups. Thirteen new solid malignancies were detected, 8 in the etanercept group and 5 in the placebo group. Compared to the general population, the risk of solid malignancies in the etanercept group was increased (SIR 3.92 [95% confidence interval 1.69–7.72]), but was not different from the risk in the placebo group compared to the general population (SIR 2.89 [95% confidence interval 0.94–6.73]). All solid malignancies occurred in patients who had been exposed to cyclophosphamide. The overall duration of disease and a history of malignancy before trial enrollment were associated with the development of malignancy during post‐trial followup.

Conclusion

The incidence of solid malignancy remained increased during long‐term followup of the WGET cohort. However, this could not be attributed solely to etanercept exposure during the trial. Anti‐TNF therapy with etanercept appears to further increase the risk of malignancy observed in patients with GPA treated with cytotoxic agents and should be avoided in these patients.
Bone edema on magnetic resonance imaging is an independent predictor of rheumatoid arthritis development in patients with early undifferentiated arthritis
Authors: Duer‐Jensen Anne , Hørslev‐Petersen Kim , Hetland Merete Lund , Bak Lene , Ejbjerg Bo Jannik , Hansen Michael Sejer , Johansen Julia Sidenius , Lindegaard Hanne Merete , Vinterberg Henrik , Møller Jakob M. , ØStergaard Mikkel
Published: April 2011

Objective

To study magnetic resonance imaging (MRI) as a tool for early diagnosis of rheumatoid arthritis (RA) in patients with early undifferentiated arthritis (UA).

Methods

Patients (n = 116) without a specific rheumatologic diagnosis, but with ≥2 tender joints and/or ≥2 swollen joints among the metacarpophalangeal, proximal interphalangeal, wrist, or metatarsophalangeal (MTP) joints for >6 weeks but <24 months, underwent clinical, biochemical, conventional radiographic, and MRI examinations and were followed up for >12 months for the final diagnosis of RA or non‐RA. Based on univariate analyses, clinical, biochemical, and imaging parameters were selected for inclusion as explanatory variables in multiple logistic regression analysis, with development of RA as the dependent variable. A prediction model was developed, and its performance was tested and compared with that of a previous model developed by van der Helm‐van Mil et al (the vdHvM model).

Results

Of the 116 patients with early UA, 27 (23.3%) developed RA. When the prediction model was applied, which included as explanatory variables presence of hand arthritis, positivity for rheumatoid factor (RF), morning stiffness lasting >1 hour, and the Outcome Measures in Rheumatology Clinical Trials MRI summary score for bone edema in the MTP and wrist joints, the outcome of RA or non‐RA was correctly identified in 82% of the patients (sensitivity 81%, specificity 82%). Another cutoff value for the prediction index in the model would allow a higher specificity (98%) and higher accuracy (83%), but lower sensitivity (36%). With the vdHvM model, RA/non‐RA was predicted in 60.2% of the population.

Conclusion

MRI evidence of bone edema in the MTP and wrist joints is an independent predictor of future RA in patients with early UA. A prediction model that includes the variables clinical hand arthritis, morning stiffness, positivity for RF, and bone edema on MRI in the MTP and wrist joints correctly identified the development or lack of development of RA in 82% of patients.
Anion‐Free Bambus[6]uril and Its Supramolecular Properties
Authors: Svec Jan , Dusek Michal , Fejfarova Karla , Stacko Peter , Klán Petr , Kaifer Angel E. , Li Wei , Hudeckova Edita , Sindelar Vladimir
Published: April 2011

Methods for the preparation of anion‐free bambus[6]uril (BU6) are presented. They are based on the oxidation of iodide anion, which is bound inside the macrocycle, utilizing dark oxidation by hydrogen peroxide or photooxidation in the presence of titanium dioxide. Anion‐free BU6 was found to be insoluble in any of the investigated solvents; however, it dissolves in methanol/chloroform (1:1) or acetonitrile/water (1:1) mixtures in the presence of the tetrabutylammonium salt of a suitable anion. The association constants with halide ions, BF4−, NO3−, and CN−, were measured by 1H NMR spectroscopy. The highest association constant (8.9×105 M−1) was found for the 1:1 complex of BU6 with I− in acetonitrile/water mixture. A number of crystal structures of BU6 complexes with various anions were obtained. The influence of the anion size on the macrocycle diameter is discussed together with an unusual arrangement of the macrocycles into separate layers.
Natural convection of nanofluids in a shallow rectangular enclosure heated from the side
Authors: Alloui Z. , Guiet J. , Vasseur P. , Reggio M.
Published: April 2011

This article reports an analytical and numerical study of natural convection in a shallow rectangular cavity filled with nanofluids. Neumann boundary conditions for temperature are applied to the vertical walls of the enclosure while the two horizontal ones are assumed insulated. Three types of nanoparticles are taken into consideration: Cu, Al2O3and TiO2. Various models are used for calculating the effective viscosity and thermal conductivity of nanofluids. The governing parameters for the problem are the thermal Rayleigh number, Ra, the Prandtl number Pr, the aspect ratio of the cavity,Aand the solid volume fraction of nanoparticles, Φ. In the first part of the analytical study a scale analysis of the present problem is made. In the second part analytical solutions are obtained, in the limit of an infinite layer ($A\gg 1$), for the stream function and temperature fields. The analytical model relies on the assumption of a parallel flow approximation in the core region of the cavity and an integral form of the energy equation in the end regions. In the high Rayleigh number regime a good agreement is obtained between the predictions of the scale analysis and those of the analytical solution. Numerical solutions of the full governing equations are obtained for a wide range of the governing parameters. A good agreement is observed between the analytical model and the numerical simulations based on the lattice Boltzmann method.

Cet article présente une étude analytique et numérique de la convection naturelle dans une cavité rectangulaire peu profonde remplie de nanofluides. Les conditions aux limites de Neumann pour la température sont appliquées sur les parois verticales de l'enceinte tandis que les deux parois horizontales sont supposées isolées. Trois types de nanoparticules sont pris en considération: Cu, Al2O3et TiO2. Divers modèles sont utilisés pour le calcul de la viscosité et la conductivité thermique effective du nanofluide. Les paramètres régissant le problème sont le nombre de Rayleigh thermique, Ra, le nombre de Prandtl Pr, le facteur de forme de la cavité, A et la fraction volumique de nanoparticules solides, phi. Dans la première partie de l'étude analytique une analyse d'échelle du problème est réalisée. Dans la deuxième partie les solutions analytiques sont obtenues, dans la limite d'une couche infinie, pour la fonction de courant et les champs de température. Le modèle de la solution repose sur l'hypothèse de l'écoulement parallèle dans la région centrale de la cavité et sur un bilan de conservation d'énergie dans les extrémités. Pour des nombres de Rayleigh assez élevés un bon accord est obtenu entre les prédictions de l'analyse d'échelle et ceux de la solution analytique. Des solutions numériques des équations complètes sont obtenues pour une large gamme des paramètres de contrôle. Un bon accord est observé entre le modèle analytique et les simulations numériques basées sur la méthode de Lattice Boltzmann. © 2011 Canadian Society for Chemical Engineering
CO2–CH4 phase equilibria on modified multi‐walled carbon nanotubes using Gibbs excess energy models based on vacancy solution theory
Authors: Ghaznavi Farzaneh , Fatemi Shohreh , Joda Marzieh
Published: April 2011

CO2 and CH4 equilibrium adsorption are predicted by Excess Gibbs energy models based on vacancy solution theory, for single and binary mixture on Multi‐Walled Carbon Nanotubes (MWCNTs) functioned by –NH2 group. The experimental data of single gas adsorption isotherms were obtained at moderate pressures and temperatures using the volumetric method in a static gaseous set up. Firstly, the equilibrium pressures related to the adsorbed amounts, for single gases, were correlated on Wilson and Flory–Huggins activity coefficient equations based on vacancy solution theory and the model parameters were determined by fitting the model on the experimental data. Secondly, the pure component parameters were implemented in extended Wilson and Flory–Huggins equations for CO2 and CH4 mixture to predict the gas–solid phase equilibria. The results showed fairly good agreement between the experiments and both Gibbs models. Finally, the studied models were compared with the popular model of Extended Langmuir. The results revealed more accurately and precisely prediction of Wilson and Flory–Huggins against Langmuir model for mixed gas of CO2 and CH4 on MWCNT–NH2. © 2011 Canadian Society for Chemical Engineering
Utilization and expense of adjuvant cancer therapies following radical prostatectomy
Authors: Spencer Benjamin
Published: April 2011

Several randomized trials and a treatment guideline favor the use of adjuvant therapy for patients with adverse pathological features identified at radical prostatectomy. This study describes the variation in patterns of utilization and costs associated with these therapies.
Reverse stage shift at a tertiary care center
Authors: Silberstein Jonathan L. , Vickers Andrew J. , Power Nicholas E. , Fine Samson W. , Scardino Peter T. , Eastham James A. , Laudone Vincent P.
Published: April 2011

BACKGROUND:

The objective of this study was to evaluate changes in clinical and pathologic characteristics of prostate cancer in patients who underwent surgery at a large tertiary care center in the context of increased use of active surveillance (AS) and minimally invasive surgery (MIS).

METHODS:

The authors retrospectively reviewed 6624 patients with localized prostate cancer who underwent radical prostatectomy from 2000 to 2010 at Memorial Sloan‐Kettering Cancer Center. Patients were stratified by surgical approach (open, laparoscopic, or robotic) and by risk category (low, intermediate, or high). Patients with low‐risk disease, without intervention, and with a minimum follow‐up of 6 months were considered to have elected AS.

RESULTS:

The number of patients who had AS increased from <20 per year between 2000 and 2004 to ≥100 per year between 2007 and 2009. Over the same decade, the number of patients who underwent MIS (laparoscopic or robotic) increased from zero to 63% of all surgical cases. The percentage of patients in the intermediate‐risk and high‐risk categories increased over time, whereas the percentage of patients in the low‐risk category decreased (odds ratio [OR] per year, 0.91; 95% confidence interval [CI], 0.89‐0.92; P < .0005). The proportion of patients who underwent surgery with Gleason 6 tumors decreased over time (OR per year, 0.87; 95% CI, 0.85‐0.88; P < .0005), whereas pathologic stage and Gleason score increased (P < .0005). The proportion of low‐risk patients decreased across all types of surgery, and the largest decrease was observed for robotic surgery (P < .0005).

CONCLUSIONS:

A reverse stage shift was observed in patients who underwent radical prostatectomy after 2000 despite the introduction and rapid proliferation of MIS. This shift may have been caused in part by the increased use of AS and an institutional focus on the treatment of higher risk disease. Cancer 2011;. © 2011 American Cancer Society.
Impact of tyrosine kinase inhibitors on the incidence of brain metastasis in metastatic renal cell carcinoma
Authors: Verma Jonathan , Jonasch Eric , Allen Pamela , Tannir Nizar , Mahajan Anita
Published: April 2011

BACKGROUND:

This study was designed to evaluate the impact of tyrosine kinase inhibitors (TKIs) on incidence of brain metastasis (brain metastasis) and overall survival (OS) in patients with metastatic renal cell cancer (mRCC).

METHODS:

All patients who presented with mRCC but no brain metastasis in the intervals 2002 to 2003 and 2006 to 2007 were identified using the institutional tumor registry. The following data were collected: age, sex, Fuhrman grade, disease sites, nephrectomy, systemic therapy including TKIs (sorafenib or sunitinib), Memorial Sloan‐Kettering Cancer Center risk category, brain metastasis treatment, and vital status. Statistical analysis was performed using the Cox proportional hazards model and the Kaplan‐Meier method.

RESULTS:

Of the 338 patients who were identified; 154 (46%) were treated with a TKI before brain metastasis, and 184 (54%) were not. There were no significant differences in age, histology, nephrectomy, involved sites of disease other than lung, or Memorial Sloan‐Kettering Cancer Center risk category between the groups. Median OS was longer in the TKI‐treated group (25 months vs 12.1 months, P < .0001). In multivariate analysis, TKI treatment (hazard ratio [HR], 0.53; 95% confidence interval [CI], 0.38‐0.74; P < .001) was associated with improved OS. Forty‐four (13%) patients developed a brain metastasis, including 29 (15.8%) of the non‐TKI group and 15 (9.7%) of the TKI group. The 5‐year actuarial rate of brain metastasis was 40% versus 17%, respectively (P < .001). TKI treatment was associated with lower incidence of brain metastasis in Cox multivariate analysis (HR, 0.39; 95% CI, 0.21‐0.73; P = .003). Lung metastasis increased the risk of brain metastasis (HR, 9.61; 95% CI, 2.97‐31.1; P < .001).

CONCLUSIONS:

Treatment with TKI agents reduces the incidence of brain metastasis in mRCC. Lung metastasis is a risk factor for brain metastasis development. Cancer 2011;. © 2011 American Cancer Society.