bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterisation of Thin Composite Films from Hyperbranched Polyphenylene and Thermolabile Hyperbranched Polycarbonate
Authors: Stumpe Katrin , Eichhorn Klaus‐Jochen , Voit Brigitte
Published: June 2008

Thin composite films made from a thermally stable hyperbranched polyphenylene and a thermolabile hyperbranched polycarbonate were prepared on silicon wafers and characterised. The end groups of the polycarbonate were varied in order to accomplish an optimised interaction between the two components and thus the formation of homogeneous blends. The composite films were annealed at 200 °C in order to decompose the hyperbranched polycarbonate which can act as a porogen. The composition of the films before and after the annealing process was investigated applying IR spectroscopy and spectroscopic ellipsometry. Analysis of the data allowed calculating the volume fractions of the two materials within the films.

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Thermal Behaviour and Glass Transition Dynamics of Inclusion Complexes of α‐Cyclodextrin with Poly(D,L‐lactic acid)
Authors: Mano João F.
Published: June 2008

Inclusion complexes (ICs) have been prepared by the host–guest interaction between α‐cyclodextrin (αCD) and poly(d,l‐lactic acid) (PDLLA). This enables transformation of the amorphous polymer into a well organized channel‐type crystalline structure, as studied by wide angle X‐ray scattering (WAXS). WAXS experiments using synchrotron radiation allowed the evolution of this crystalline structure to be followed upon heating. The diffraction peaks disappeared above 320 °C, in a temperature region similar to the occurrence of thermal degradation, also investigated by thermogravimetric analysis. No glass transition could be detected in the IC using differential scanning calorimetry (DSC), but non‐conventional dynamic mechanical analysis measurements revealed the existence of loss factor peaks shifted to higher temperatures when compared with PDLLA. The relaxation plot of the IC was characterized by an Arrhenius behaviour with a high activation energy that could be consistent with the high geometrical confinement felt by the chains in the nanostructured organization.

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Degradation Mechanisms of Biodegradable Poly(DL‐lactide‐co‐glycolide)1000 Diacrylate Network as Studied by Proton Solid‐State Flow NMR Relaxometry
Authors: Litvinov V. M. , Plum B. , Boerakker M. , Dias A. A.
Published: June 2008

Summary:Degradation mechanisms of biodegradable photo‐polymerised poly(DL‐lactide‐co‐glycolide)1000 diacrylate {[(DL‐LA/GA)DA]} matrices or films were studied by proton solid‐state NMR relaxometry. A flow NMR unit cell was developed for this purpose. The (DL‐LA/GA)DA‐network was degraded in PBS buffer solution of pH = 7.4. A real‐time proton NMR method provided information about the staged break down of the network during continuous circulation of the buffer solution through the NMR tube. The current study shows that degradation of the network proceeds in three stages: 1 ‐ extraction of a sol fraction that causes substantial immobilization of the material, 2 ‐ scissions of network chains producing network defects without formation of extractable products, and 3 – finally, chain scissions that cause formation of a sol fraction and complete degradation of the material. It was shown that the [(DL‐LA/GA)DA‐network was composed of rigid and viscoelastic domains on all stages of degradation. This heterogeneity could be due to heterogeneous spatial distribution of network junctions in the initial network and/or nano‐scale phase separation of polyacrylate chains that form multifunctional network junctions and poly(lactide‐co‐glicolide) network chains. A combination of bulk and surface erosion both on nano‐ and macroscopic scales could explain the observed degradation mechanisms. It is shown that knowledge of weight loss upon hydrolytic degradation is not sufficient for understanding degradation mechanisms in the relation to functional properties of this type of hydrogels.
A new Phosphorylated Polysaccharide for Biomedical Applications: Generation of 3D Scaffolds with Osteogenic Activity and Coating of Titanium Oxide Surfaces
Authors: Pasqui Daniela , Danieli Elisa , Leone Gemma , Torricelli Paola , Barbucci Rolando
Published: June 2008

Summary:A new phosphorylated derivative of carboxymethylcellulose and amidic carboxymethylcellulose containing one phosphate group for each disaccharide unit was synthesized using sodium trimetaphospahte (STMP) as the phosphating agent. The new polysaccharide was characterized by infrared spectroscopy (FT‐IR) and the amount of phosphate groups was determined by elemental analysis. These modified polysaccharides were used both to prepare 3D scaffolds and functionalize titanium oxide surfaces with the aim to improve the osseointegration with the host tissue. The presence of phosphate groups modify the physical‐chemical properties of the hydrogels with respect to the native ones. The evaluation of the bioactivity of the phosphorylated carboxymethylcellulose hydrogels towards osteoblast‐like cells showed a significant increase in the osteocalcin production. The modified surfaces were chemically characterized by means of X‐ray photoelectron spectroscopy (XPS) and FT‐IR, whereas the surface topography was analysed by Atomic Force Measurements (AFM) measurements before and after the polysaccharide coating. In vitro biological tests using osteoblast‐like cells demonstrated that phosphorylated carboxymethylcellulose functionalized TiO2 surfaces promoted better cell adhesion and significantly enhanced their proliferation. These findings suggest that the phosphate polysaccharide both as a 3D scaffold and as a surface coating promotes osteoblast growth potentially improving the biomaterial osseointegration rate.
Novel Poly(amidoamine)‐Based Hydrogels as Scaffolds for Tissue Engineering
Authors: Emilitri Elisa , Guizzardi Fabiana , Lenardi Cristina , Suardi Marco , Ranucci Elisabetta , Ferruti Paolo
Published: June 2008

Summary:Poly(amidoamine)s are biocompatible biodegradable polymers, which can be easily functionalized with a number of bioactive and biomimetic compounds. Co‐polymerization of these polymers with 4‐aminobutyl guanidine (agmatine) leads to an RGD mimicking structure. Hydrogels based on this structure showed an enhanced cell adhesion and could be chemically linked to a glass substrate to create a bioadhesive support for cell growth. Preliminary optimization and cell adhesion tests on Madin‐Darby Canine Kidney cells were performed, both on functionalized and non‐functionalized structures, with promising results.
Negative Temperature Sensitive Hydrogels in Controlled Drug Delivery
Authors: Geever Luke , Cooney Ciaran , Devine Declan , Devery Sinead , Nugent Michael , Higginbotham Clement
Published: June 2008

Summary:PVP/PNIPAAm copolymers exhibit a temperature sensitive nature that makes them an attractive candidate for controlled drug delivery devices. Diclofenac sodium was added to the monomeric mixture, which included an initiator and crosslinking agent (where appropriate), prior to UV photopolymerisation. It was found that the xerogels retained similar properties as the original samples (not containing drug) at lower levels of drug integration. In all cases, drug dissolution analysis showed that the active agent was released at a slower rate at temperatures above the Lower Critical Solution Temperature (LCST). Interestingly, the drug release trends were almost identical for both the physically and chemically crosslinked hydrogels, when the decrease in transition temperature caused by the incorporated crosslinking agent is taken into consideration. It is believed that both types of copolymers reached a constant maximum swollen weight at a set of temperatures above their transition temperatures. When this swollen plateau is attained, the hydrophilic‐hydrophobic interactions are balanced, thus the gel does not swell or shrink further and the drug diffuses out at a constant rate.
Characterisation of Redox Initiators for Producing Poly(Vinyl Alcohol) Hydrogels
Authors: Martens Penny , Grant Michele , Nilasaroya Anastasia , Whitelock John , Poole‐Warren Laura
Published: June 2008

Summary:This work focuses on the characterisation of ascorbic acid/persulphate initiating system. Three different persulphates were used (ammonium, potassium and sodium), and a range of initiator concentrations were tested. Gel time, gel quality, initiator toxicity, and cell survival upon encapsulation were measured. No significant differences were observed between the three types of persulphates. Higher concentrations of the initiators resulted in faster gel times (5min for 0.05wt% initiator) and higher quality gels (less than 20% sol fraction), although the lower initiator concentrations were better in terms of cell growth inhibition and survival upon encapsulation. Overall, this system shows great promise for use in biomedical applications, however there is a need to minimise the initiator concentration to increase cell compatibility while maintaining a high enough concentration for adequate gel formation.
An Artificial Disc: Chemical and Biomechanical Analysis
Authors: Mercuri D. , Leone G. , Barbucci R. , Favaloro R. , Facchini A. , Signori F. , Bronco S. , Ciardelli F.
Published: June 2008

Summary:Degeneration of intervertebral discs is the most common cause of back pain. The first phase of this degenerative process involves the nucleus pulposus. A rapid recovery of this structure can prevent further degradation of the annulus fibrosus. Guar Gum is an hydrophilic polysaccharide extracted from the seed endosperm of a plant. Through a cross‐linking procedure a Guar hydrogel was synthesized. The Guar hydrogel could be injected by a syringe and it is a good candidate as a nucleus pulposus substitute. For the preparation of the artificial fibrosus annulus, commercially available polymer materials are tuned to achieve suitable mechanical properties. To achieve this peculiar behaviour, the main strategy investigated is the dispersion of hollow polymer micro spheres in a thermoplastic polymer matrix. Processing conditions and particle content are finely tuned to get the target mechanical behaviour.
Preparation of Porous Protein‐Based Hydogel for Highly Sensitive Protein Chips
Authors: Tanaka Hiroyuki , Shiroya Toshifumi , Hanasaki Minako , Isojima Tatsushi , Takeuchi Hisao , Kawaguchi Haruma
Published: June 2008

Summary:Protein chips are important tools for high‐throughput analysis of biological events. We have developed a novel method to prepare a protein‐based hydrogel, that is, a “Three‐Dimensional Nano‐structured Protein Hydrogel” (3‐D NPH), which is composed of protein and polymer nano‐particles. The 3‐D NPH could be easily prepared by dispensing a protein and polymer mixture on a substrate. Surprisingly, gold particles conjugated with protein A diffused into the 3‐D NPH which was made of mouse IgG through the pores. We have shown that the protein chips made with our 3‐D NPH method has tremendously improved sensitivity in detecting protein‐protein interactions compared with that of direct protein immobilization methods.
Stimulations of Responsive Hydrogels: Experimental Investigations and Modelling
Authors: Maurer Gerd
Published: June 2008

Summary:Modelling the responses of hydrogels to external stimulations requires a thermodynamic framework for the phase equilibrium between a gel and a surrounding phase and models for describing the Gibbs energies of both phases. The phase equilibrium conditions are described and some appropriate models for describing the thermodynamic properties are presented. These methods are applied to describe (correlate/predict) the swelling of nonionic hydrogels (of n‐isopropyl acrylamide) and ionic hydrogels (of n‐isopropyl acrylamide and sodium methacrylate) in various nonionic and ionic aqueous solutions at 298 K.
Micro and Macro Characterization of PEO‐PPO‐PEO Triblocks Hydrogels
Authors: Fusco S. , Borzacchiello A. , Cohn D. , Netti P. A.
Published: June 2008

Summary:Amphiphilic poly(ethylene oxide) ‐ poly(propylene oxide) triblock copolymers are very appealing materials for biomedical application since they can be easily injected as liquid at room temperature while they produce a gel when in the body. On the other hand, these materials no longer hold the gel state when in presence of solvent (as physiological solutions) due to the dilution of the system. To overcome these limitations Cohn and coworkers1 have synthesized a novel thermo‐responsive systems by extending the chain of the commercially available PEO‐PPO copolymer named F127. The aim of this study was to evaluate the effect of the chemical modification on the macroscopic, rheological, and microscopic, transport, properties of these new materials.
Elucidation of the Mechanism of Enhanced Insulin Uptake and Release from pH Responsive Hydrogels
Authors: Tuesca Anthony , Lowman Anthony
Published: June 2008

Summary:Environmentally responsive hydrogels composed of poly(methacrylic acid‐g‐ethylene glycol) (P(MAA‐g‐EG)) have shown promise for oral insulin delivery due to their pH responsive complexation behavior. A series of hydrogel formulations were polymerized with varying amounts of crosslinker and varying monomer volume fraction. The mesh size of the network depended primarily on pH, varying from 8.0 to 27.2 nm. Insulin loading efficiency varied directly with crosslink density, ranging from 42.7 to 84.9% of available insulin loaded into the hydrogels. The release of insulin was performed with each polymer formulation at 5 pH levels ranging from 2.7 to 6.8. Insulin release was less than 20% for all formulations tested with insulin for the duration of the 3 hour release study for all pH levels considered except when the pH was 6.8, at which point the release occurred as a burst. Loading studies performed with insulin glargine, an insulin analog with an increased pI, showed the same trends as native insulin. However, the release of insulin glargine only occurred at a pH level above that of the pI of the protein. These results indicate that hydrogen bonds and ionic interactions between the protein and P(MAA‐g‐EG) may strongly influence its loading and release behavior in vitro.
Recurrent metastatic neuroblastoma followed by myelodysplastic syndrome: Possible leukemogenic role of temozolomide
Authors: Kushner Brian H. , Laquaglia Michael P. , Kramer Kim , Modak Shakeel , Cheung Nai‐Kong V.
Published: June 2008

An 8‐year old child had a pelvic MYCN‐nonamplified neuroblastoma (NB) with retroperitoneal nodal extension. Multi‐modality therapy achieved complete remission (CR). Small recurrences confined to left supraclavicular nodes were treated with surgery alone at 4.9, 6.5, 7.5, 9.5, and 12.9 years from diagnosis. Monitoring through 12 months after the last resection showed CR. When she returned 34 months later (16.8 years from diagnosis), she had massive disease in the left neck and upper trunk, without osteomedullary metastases. Salvage therapy featured 11 cycles of temozolomide. She developed myelodysplastic syndrome with 45,XX,der(7)t(7;21) (p15;q11),‐21 at age 24 and refused treatment; 19 months later she was transfusion‐dependent but her NB remained in CR. Pediatr Blood Cancer 2008;51:552–554. © 2008 Wiley‐Liss, Inc.
Virilizing ovarian tumor in a 14‐year‐old female with a prior familial multinodular goiter
Authors: Niedziela Marek
Published: June 2008

A 14‐year‐old female presented with intermittent abdominal pain, deepening of voice and amenorrhoea for 4 months. Twelve months earlier she had had a thyroidectomy because of familial multinodular goiter and had, subsequently, received substitution with L‐thyroxine. At the time of admission, a high serum testosterone level was detected. The dexamethasone suppression test confirmed the hormonal autonomy and magnetic resonance imaging (MRI) visualized a solid tumor within the left ovary. The pathological diagnosis after left salpingo‐oophorectomy was Sertoli‐Leydig cell tumor. The patient has remained disease‐free for 6 years. Pediatr Blood Cancer 2008;51:543–545. © 2008 Wiley‐Liss, Inc.
Preparation and characterization of nanocomposite material based on polyurethane acrylate macromonomer
Authors: Fang Shao‐Ming , Zhou Li‐Ming , Gao Li‐Jun , Liu Dong‐Liang , Zhang Hai‐Bo
Published: June 2008

In the present investigation, a macromonomer of polyurethane acrylate (PUA) was synthesized, and novel netlike nanocomposite materials were prepared through in situ polymerization of polyurethane acrylate macromonomers in the presence of organically modified montmorillonite (oMMT). The structure of oMMT was compared with untreated MMT by Fourier transform infrared (FTIR) and X‐ray diffraction (XRD). Transmission electronic microscopy (TEM) studies showed that the silicate layers of oMMT were dispersed homogeneously in the polymer matrix. Tensile test, impact test, and thermal gravity analysis proved that the mechanical and thermal properties of the nanocomposites are superior to those of the pure system, and the mechanical properties of the cured hybrid reach maximum while the content of oMMT is 1.5 wt%. Surprisingly, dynamic mechanical thermal analysis (DMTA) displayed that the glass transition temperature (Tg) of the nanocomposites decreased with increasing the oMMT contents. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
The shock and release behavior of an aerospace‐grade cured aromatic amine epoxy resin
Authors: Hazell P.J. , Stennett C. , Cooper G.
Published: June 2008

Knowing the dynamic behavior of polymer materials that are used in the construction of fiber‐reinforced composite materials is particularly important for such materials that are subjected to impact. In this work, we have conducted a number of plate‐impact experiments on a commercially important aromatic amine epoxy resin that is used in the construction of carbon fiber composite materials. The measured Hugoniot in shock velocity–particle velocity space was Us = 2.65 + 1.55 up (ρ0 = 1.141 g/cc), and is similar to the measured Hugoniots of other resins presented by different researchers. We have also measured the longitudinal stress in the shocked material and shown, in common with other polymers, that above a threshold stress, an increase in shear strength with impact stress is observed. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Preparation, structure, and properties of the PTT/SGF composites
Authors: Run Mingtao , Song Hongzan , Hao Yanping , Hu Xiaomin , Yao Chenguang
Published: June 2008

Short glass fiber reinforced poly(trimethylene terephthalate) composites (PTT/SGF) were prepared by twin screw extruder. The structural feature and physical properties of these composites were studied by scanning electron microscope, differential scanning calorimetry, thermalgravimetric analyzer, capillary rheometer, universal tester, etc. The glass fiber was modified by the silane coupling agent before being blended with the polymer. The results suggest that there is strong interaction between SGF and PTT matrix, which leads to an increasing on the tensile strength, Young's modulus, impact strength and thermal stability of the composites with proper contents of SGF. Rheological behavior of the PTT/SGF composites melt is complicated, combining a dilate fluid at lower shear rate and a pseudo‐plastic fluid at higher shear rate. The melt apparent viscosity of composites decreases with increasing SGF content because of the rigid fibers improving the flow of the melt. Moreover, the flow activation energy of the composites suggests that the melt with more SGF has lower sensitivity to the processing temperature. In conclusion, the composite with 10–20 wt% content of SGF has better properties. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Ethylene vinyl acetate/Mg‐Al LDH nanocomposites by solution blending
Authors: Kuila T. , Acharya H. , Srivastava S.K. , Bhowmick A.K.
Published: June 2008

Partially exfoliated ethylene vinyl acetate (EVA‐40, 40% vinyl acetate content)/layered double hydroxide (LDH) nanocomposites using organically modified layered double hydroxide (DS‐LDH) have been synthesized by solution intercalation method. X‐ray diffraction (XRD) and transmission electron microscopy (TEM) studies of nanocomposites shows the formation of exfoliated LDH nanolayers in EVA‐40 matrix at lower DS‐LDH contents and partially intercalated/exfoliated EVA‐40/MgAl LDH nanocomposites at higher DS‐LDH contents. These EVA‐40/MgAl LDH nanocomposites demonstrate a significant improvement in tensile strength and elongation at break for 3 wt% of DS‐LDH filler loading compare to neat EVA‐40 matrix. Thermogravimetric analysis also shows that the thermal stability of the nanocomposites increases with DS‐LDH content in EVA‐40. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Study of the modification of the properties of (PP/EPR) blends with a view to preserving natural resources when elaborating new formulation and recycling polymers
Authors: Mnif Nizar , Massardier Valérie , Kallel Tasnim , Elleuch Boubaker
Published: June 2008

The aim of the present work is to study how CaCO3, very abundant on earth, can be blended with polypropylene/ethylene propylene rubber (PP/EPR) either to preserve natural resources when elaborating virgin formulations or to simulate mixtures of waste made of CaCO3 filled PP with PP/EPR which could result from end‐of‐life‐vehicles (ELV). The article focuses on the studies of PP/EPR blends, used in the manufacture of automobile fenders, in the presence of nano‐CaCO3 and compatibilizers. Blends of various compositions (with and without compatibilizer and nanoparticles) were prepared using a corotating twin‐screw extruder. The results were compared with the ones presented by a commercial (PP/EPR) blend. The experiments included mechanical tests, differential scanning calorimetry, scanning electron microscopy, and dynamic mechanical analysis experiments. The presence of the compatibilizers in the (PP/EPR) blends decreases the size of elastomer particles, improves the adherence to the interface and improves the mechanical properties. The nano‐CaCO3 would also seem to act as a nucleating agent in the PP/EPR matrix; it increases the cristallinity and the Young modulus of the blends. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Morphology, mechanical, and dielectric breakdown properties of PBT/PET/TPE, PBT/PET/PA66, PBT/PET/LMPE, and PBT/PET/TiO2 blends
Authors: Park Eun‐Soo
Published: June 2008

The morphology and thermal behavior of tertiary blends of poly(butylene terephthalate) [PBT]/poly(ethylene terephthalate) [PET] alloy resin (Alloy)/thermoplastic elastomer (TPE), Alloy/nylon 66 (PA66), Alloy/low molecular weight polyester (LMPE), and Alloy/titanium dioxide (TiO2) have been investigated by scanning electron microscopy, differential scanning calorimetry, and thermogravimetry (TG). In case of TPE and LMPE containing blends did not show any morphological change compared with Alloy whereas for PA66 containing blends, the size of the dispersed phase increased with the increase the PA66 contents. The crystallization peak of Alloy/TPE blends became undetectable with an increasing TPE content. In contrast, the crystallization temperature (Tc1) of Alloy/PA66, Alloy/LMPE, Alloy/TiO2 blends increased significantly as the PA66, LMPE, and TiO2 content increases. TG traces show a significant shift of the weight loss towards higher temperature for Alloy/TiO2 blend whereas Alloy/TPE, Alloy/PA66 and Alloy/LMPE blends slightly decreases in thermal stability than Alloy. To investigate the applicability for insulation material, the prepared blend samples were extruded an electric wire and the breakdown voltage (BDV) of wires was investigated. The melt flow rate of Alloy increased as the amount of TPE increased, and a contrary trend was found when the increase of the amount of TiO2. The dielectric breakdown test applies a voltage that is greater than the product's rated operating voltage for a specific period of time during which dielectric breakdown must not occur. The BDV of Alloy/TPE and Alloy/PA66 blends is higher than other blends before and after thermal aging 225°C for 30 min. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
In situ reinforcement of poly(butylene terephthalate) and butyl rubber by liquid crystalline polymer
Authors: Kumar S. , Rath T. , Mahaling R.N. , Das C.K. , Srivastava R.B. , Yadaw S.B.
Published: June 2008

Ternary in situ butyl rubber (IIR)/poly(butylene terephthalate) (PBT) and liquid crystalline polymer (LCP) blends were prepared by compression molding. The LCP used was a versatile Vectra A950, and the matrix material was IIR/PBT 50/50 by weight. Morphological, thermal, and mechanical properties of blends were investigated using scanning electron microscopy (SEM), atomic force microscopy (AFM), differential scanning calorimetry, and thermogravimetric analysis (TGA). Microscopy study (SEM) showed that formation of fibers is increasing with the increasing amount of LCP A950. Microscopic examination of the fractured surface confirmed the presence of a polymer coating on LCP fibrils. This can be attributed to some interactions including both chemical and physical one. The increased compatibility in polymer blends, consisting of IIR/PBT, by the presence of LCP A950 may be explained by the adsorption phenomena of the polymer chains onto the LCP fibrils. SEM and AFM images provided the evidence of the interaction between IIR/PBT and the LCP. Dynamic mechanical analyses (DMA) and TGA measurements showed that the composites possessed a remarkably higher modulus and heat stability than the unfilled system. Storage modulus for the ternary blend containing 50 wt% of LCP exhibits about 94% increment compared with binary blend of IIR/PBT. From the above results, it is suggested that the LCP A950 can act as reinforcement agent in the blends. Moreover, the fine dispersion of LCP was observed with no extensional forces applied during mixing, indicating the importance of interfacial adhesion for the fibril formation. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Preparation and characterization of chitosan/KSF biocomposite film
Authors: Altınışık Aylin , Seki Yoldaş , Yurdakoç Kadir
Published: June 2008

Chitosan–clay biocomposites have been prepared in which KSF‐montmorillonite (KSF) is used as filler and diluted acetic acid is used as solvent for dissolving and dispersing chitosan and montmorillonite, respectively. The effect of KSF loadings in biocomposites has been investigated. The characterization with different methods (FTIR, DSC, TGA, SEM, and XRD) on chitosan/KSF biocomposites systems was examined. Morphology and properties of chitosan biocomposites have been studied compared with those of pure chitosan. The FTIR and SEM results indicated the formation of an intercalated‐and‐exfoliated structure at low KSF content and an intercalated‐and‐flocculated structure at high KSF content. The thermal stability and the mechanical properties of the composites were also examined by DSC, TGA/DTG, and tensile strength measurements, respectively. The dispersed clay improves the thermal stability of the matrix systematically with the increase of clay loading. Tensile strength of a chitosan film was enhanced until the clay ratio up to 2 wt% and elongation‐at break decreased with addition of clay into the chitosan matrix. The XRD results confirmed the intercalation of the biopolymer in the clay interlayer by the decrease of 2θ values while the chitosan–clayratio increases. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Effects of resin storage aging on rheological property and consolidation of composite laminates
Authors: Gu Yizhuo , Li Min , Zhang Zuoguang , Li Yanxia
Published: June 2008

The ability to predict the viscosity of thermoset resin is important to understand the manufacturing process of composites and optimize the processing parameters. During resin or prepreg storage course, the cure reaction may happen and the degree of cure increases gradually. The storage aging effect reduces the fluidity of resin, and hence alters the processability of resin. In this article, the rheological properties of an epoxy resin and a bismaleimide resin used in composite autoclave process were measured and a viscosity model was established, which can predict the viscosity progression during cure for different aging degree of resin. Moreover, a computer simulation method was used to study the effects of aging degree on the composite consolidation and the processing operations. It is found that the viscosity model of aged resin can be obtained by modified dual Arrhenius model of fresh resin with the dynamic rheological measurement. The resin aging strongly alters the flowability, so influences composite consolidation. According to the simulated results, the processing parameters need to be adjusted to achieve cured composites with appropriate fiber content. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Synthesis of polyacrylate/poly(ethylene glycol) hydrogel and its absorption properties for heavy metal ions and dye
Authors: Tang Qunwei , Wu Jihuai , Sun Hui , Fan Shijun , Hu De , Lin Jianming
Published: June 2008

A novel polyacrylate/poly(ethylene glycol) (PAA/PEG) hydrogel was synthesized by a simple two‐step aqueous prepolymerization method. The deswelling properties were investigated in the case of changing the neutralization degrees of PAA, the pHs and the concentration of multivalent salt solutions. Methyl orange (MO) dye can be adsorbed and released using the swelling–deswelling property of the PAA/PEG hydrogel. The PAA/PEG hydrogel can adsorb MO of 29 mg/g at equilibrium and release about 80% in 30 min. Based on the deswelling property, the dyes in wastewater can be reclaimed and reused. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Diffusion‐weighted MR imaging and apparent diffusion coefficient of the normal fetal lung: preliminary experience
Authors: Manganaro Lucia , Perrone Anna , Sassi Simona , Fierro Francesca , Savelli Sara , Di Maurizio Marco , Tomei Alessandra , Francioso Antonella , La Barbera Laura , Giancotti Antonella , Ballesio Laura
Published: June 2008

Objective

To assess if a correlation is present between apparent diffusion coefficient (ADC) values and normal lung maturation during gestation to define potential reference values as indicators of the lung development.

Methods

Our study included 50 pregnant women (gestational age, GA: 18–36 weeks), with normal fetal development of lungs assessed by a previous obstetric ultrasound (US), and then confirmed by our magnetic resonance (MR) examination. We used T2‐weighted sequences, diffusion‐weighted imaging sequences (DWI) and ADC maps for studying pulmonary tissue. In all cases the resulting ADC values were related to GA using Pearson correlation.

Results

ADC values ranged from 1,2 µm2/ms at 18 weeks' gestation to 3,9 µm2/ms at 36 weeks' gestation with a mean value, regardless for the gestational age, of 2, 352 ± 0,623106 µm2/ms. We found a significant correlation between ADC and gestational age (Pearson correlation = 0,816).

Conclusion

The ADC values correlate with gestational age since alveolar fluid secretion and angiogenesis increase gradually. Therefore, ADC can be considered as a new parameter for studying lung maturity. Copyright © 2008 John Wiley & Sons, Ltd.
Expectation and knowledge of pregnant women undergoing first and second trimester ultrasound examination in a Chinese population
Authors: Chan Lin Wai , Chan Oi Ka , Chau Mo Ching Macy , Sahota Daljit Singh , Leung Tak Yeung , Fung Tak Yuen , Lau Tze Kin
Published: June 2008

Objective

To evaluate expectation and knowledge on obstetric ultrasound examination in the first and second trimester in a Chinese population.

Method

A cross‐sectional survey was conducted in a university obstetric clinic in Hong Kong. Chinese pregnant women who underwent the first trimester early scan sessions, or the second trimester anomaly scan sessions were invited to complete a self‐administered questionnaire, which contained items on their knowledge, expectation, and sociodemographic characteristics.

Results

In all 276 eligible pregnant women (117 in the first trimester and 159 in the second trimester) were recruited. Although 249 women (90.2%) claimed they understood the indication of the ultrasound examination, only 93 of them were correct (33.7%). The median perceived overall‐detection rate for structural abnormalities was 66.5%. Living in Hong Kong for more than 7 years was significantly associated with higher knowledge level and expectation from ultrasound examination. Attaining tertiary education level was also significantly associated with higher knowledge level. Over 90% of the pregnant women studied wished to know the fetal gender from the anomaly scan examination.

Conclusion

Knowledge of Chinese pregnant women on ultrasound was generally unsatisfactory. Understanding their limitation of knowledge and expectations helps to devise appropriate education in the local setting. Copyright © 2008 John Wiley & Sons, Ltd.
A novel nutraceutical property of select sorghum (Sorghum bicolor) brans: inhibition of protein glycation
Authors: Farrar Johnetta L. , Hartle Diane K. , Hargrove James L. , Greenspan Phillip
Published: June 2008

Despite the high levels of polyphenolic phytochemicals in grain sorghum and its position as a major food staple, there has been a lack of research on its effects on both animal and human health and disease prevention. These phenolic compounds, mainly located in the bran fraction, result in the plant having substantial antioxidant properties. This study examined the effect of ethanol extracts of several varieties of sorghum (S. bicolor) bran on albumin glycation, a non‐enzymatic process thought to be important in the pathogenesis of many diabetic complications. Sorghum brans with a high phenolic content and high antioxidant properties inhibited protein glycation, whereas sorghum brans that are low in these properties did not inhibit this process. Ethanol extracts of wheat, rice or oat bran did not inhibit protein glycation. Although one high phenolic sorghum bran variety (sumac) inhibited protein glycation by approximately 60%, it produced only a 20% decrease in methylglyoxal mediated albumin glycation. These results suggest that certain varieties of sorghum bran may affect critical biological processes that are important in diabetes and insulin resistance. These results distinguish select sorghum brans from the common food brans and suggest a nutraceutical rationale for its human consumption. Copyright © 2008 John Wiley & Sons, Ltd.
NF‐κB inhibitory activity of compounds isolated from Cantharellus cibarius
Authors: Kim Jeong Ah , Tay David , Blanco Esperanza Carcache de
Published: June 2008

The inhibitory activities of the extracts of Cantharellus cibarius and isolated compounds were investigated in an enzyme‐based ELISA NF‐κB assay. Of the tested compounds, ergosterol, ergosterol peroxide and cerevisterol were noted to have the most potent inhibition of NF‐κB activation. The ability of the active metabolites to inhibit the NF‐κB translocation from the cytoplasm to the nucleus was assessed using a cell‐based NF‐κB assay. The isolated compounds were elucidated through the analysis of various spectroscopic methods. Copyright © 2008 John Wiley & Sons, Ltd.
The in vitro effects of Mondia whitei on human sperm motility parameters
Authors: Lampiao Fanuel , Krom Debby , Plessis Stefan S. du
Published: June 2008

Mondia whitei has been used since ancient times as an aphrodisiac even though little scientific evidence exists about its efficacy. An aqueous extract of Mondia whitei was administered to human spermatozoa in vitro and motility parameters assessed. Mondia whitei significantly enhanced total motility as well as progressive motility in a time‐dependent manner. These data may open the way for the use of Mondia whitei especially in men affected with asthenozoospermia. Copyright © 2008 John Wiley & Sons, Ltd.
Synergistic antitumor effects of liposomal honokiol combined with adriamycin in breast cancer models
Authors: Hou Wenli , Chen Lijuan , Yang Guangli , Zhou Hang , Jiang Qiqi , Zhong Zhenhua , Hu Jia , Chen Xiang , Wang Xianhuo , Yuan Yuan , Tang Minghai , Wen Jing , Wei Yuquan
Published: June 2008

Honokiol, a novel antitumor agent, could induce apoptosis and inhibit the growth of vascular endothelium in several tumor cell lines and xenograft models. It has been suggested that the antitumor effect of chemotherapy could be increased by combining it with an antiangiogenesis agent in anticancer strategy. The present study explored the potential to increase the antitumor effect of adriamycin by combining it with honokiol in mouse 4T1 breast cancer models, and the underlining mechanism was investigated. Honokiol was encapsulated in liposomes to improve the water insolubility. In vitro, liposomal honokiol inhibited the proliferation of 4T1 cells via apoptosis and significantly enhanced the apoptosis of 4T1 cells induced by adriamycin. In vivo, the systemic administration of liposomal honokiol and adriamycin significantly decreased tumor growth through increased tumor cell apoptosis compared with either treatment alone. Collectively, these findings suggest that liposomal honokiol may augment the induction of apoptosis in 4T1 cells in vitro and in vivo, and this combined treatment has shown synergistic suppression in tumor progression according to the analysis of isobologram. The present study may be important in future exploration of the potential application of the combined approach in the treatment of breast cancer. Copyright © 2008 John Wiley & Sons, Ltd.
Preliminary investigation of the central nervous system effects of ‘Tira‐capeta’ (Removing the Devil), a cigarette used by some Quilombolas living in Pantanal Wetlands of Brazil
Authors: Rodrigues Eliana , Gianfratti Bruno , Tabach Ricardo , Negri Giuseppina , Mendes Fúlvio R.
Published: June 2008

During an ethnopharmacological survey carried out among some Quilombolas living in Brazil, 48 plants with possible central nervous system (CNS) action were cited. A mixture of nine plants, known as ‘Tira‐capeta’ (Removing the Devil) cigarette, has been utilized for years as a tonic for the brain. The effects observed after consuming this cigarette are: dizziness, lightness sensation, humor changes, yawns, heavy eyes, hunger, sleep and relaxation. This study aimed to verify the effects of a hydroalcohol extract of ‘Tira‐capeta’ cigarette (ETC), as well as to evaluate the phytochemical profile. The phytochemical screening carried out through characterization reactions, thin layer chromatography and high efficiency liquid chromatography indicated the presence of tannins, phenolic acids, flavonoids, saponins and alkaloids; tannins and phenolic acids being the principal constituents. The pharmacological tests showed that ETC induced a biphasic effect, with intense initial stimulation of the CNS, followed by a general depressor state; decreased the latency for sleeping and increased the total sleeping time (50, 100 and 500 mg/kg), without causing prejudice in motor coordination (doses up to 200 mg/kg); induced catalepsy in mice, verified 10 and 50 min after drug administration (500 mg/kg). Also, no anxiolytic or anxiogenic effects were verified in rats submitted to the elevated plus‐maze. Copyright © 2008 John Wiley & Sons, Ltd.
Clinical outcomes of diabetic foot management with Circulat
Authors: Olalde J. A. , Magarici M. , Amendola F. , Castillo O. del , Gonzalez S. , Muhammad A.
Published: June 2008

Major and minor lower‐extremity amputation is a common complication among diabetics. Various sources indicate diabetic foot ulcer prevalence at between 2.2% and 15% in diabetics. This study evaluates the efficacy and tolerance of a standardized plant extract combination, Circulat, developed for the prevention and treatment of severe manifestations of type 2 diabetes, such as necrotic damage of the foot. Thus, a retrospective cohort study was carried out in 174 patients treated with Circulat with diabetic foot grades D1–D3, according to The University of Texas Wound Classification System, in 50 medical centers, from 2004 to 2007. Circulat obtained 50.57% complete cure of diabetic foot, significant improvement in 37.9% and prevented amputation in 88.5% of the study's total population. The treatment was well tolerated. Four patients (2.3%) had slight gastrointestinal unrest which did not warrant suspension of treatment. Copyright © 2008 John Wiley & Sons, Ltd.
Aqueous garlic extract attenuates hepatitis and oxidative stress induced by galactosamine/lipoploysaccharide in rats
Authors: El‐Beshbishy Hesham A.
Published: June 2008

Injection of D‐galactosamine and lipopolysaccharide (DGaIN/LPS) is useful as an experimental model of acute hepatic damage. Juvenile rats were used for investigation. The hepatoprotective activity of aqueous garlic (Allium sativum) extract (AGE) at a dose of 300 mg/kg body weight for 14 days, intraperitoneal (i.p.) prior to the induction of DGalN/LPS, was investigated against DGalN/LPS‐induced hepatitis in rats. DGalN/LPS (300 mg/kg body weight/30 µg/kg body weight, i.p.), induced hepatic damage that was manifested by a significant increase in the activities of marker enzymes [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and gamma glutamyl transferase (γGT)], bilirubin, lipid peroxides (LPO), tumor necrosis factor (TNF‐α) and myeloperoxidase (MPO) activity level in serum. Also, the lipid profile in serum and liver homogenate including total cholesterol, triglycerides, free fatty acids and phospholipids were significantly deteriorated. The antioxidant enzyme activities (superoxide dismutase, SOD; reduced glutathione, GSH; catalase, CAT and glutathione peroxidase, GPX) in liver homogenate were significantly decreased in the DGalN/LPS. Pretreatment of rats with AGE reversed these altered parameters near to normal control values. Results of this study revealed that AGE could afford a significant protection in the alleviation of DGalN/LPS‐induced hepatic damage. Copyright © 2008 John Wiley & Sons, Ltd.
A clustering approach to identify the time of a step change in Shewhart control charts
Authors: Ghazanfari Mehdi , Alaeddini Adel , Niaki Seyed Taghi Akhavan , Aryanezhad Mir‐Bahador
Published: June 2008

Control charts are the most popular statistical process control tools used to monitor process changes. When a control chart indicates an out‐of‐control signal it means that the process has changed. However, control chart signals do not indicate the real time of process changes, which is essential for identifying and removing assignable causes and ultimately improving the process. Identifying the real time of the change is known as the change‐point estimation problem. Most of the traditional methods of estimating the process change point are developed based on the assumption that the process follows a normal distribution with known parameters, which is seldom true. In this paper, we propose clustering techniques to estimate Shewhart control chart change points. The proposed approach does not depend on the true values of the parameters and even the distribution of the process variables. Accordingly, it is applicable to both phase‐I and phase‐II of normal and non‐normal processes. At the end, we discuss the performance of the proposed method in comparison with the traditional procedures through extensive simulation studies. Copyright © 2008 John Wiley & Sons, Ltd.
DFT study for the reactions of H atoms with CH3OH and C2H5OH
Authors: Carvalho Edson F. V. , Barauna Alessandra N. , Machado Francisco B. C. , Roberto‐Neto Orlando
Published: June 2008

Density functional theory (DFT) geometries, vibrational frequencies, barrier heights, and reaction energies are computed for the first reactive channels of reactions involving the hydrogen atoms with CH3OH and C2H5OH. For both reactions, the density functional BB1K specially fitted to study hydrogen abstraction reactions was able to give barrier heights and reaction enthalpies at 0 K with accuracy close to 1.0 kcal/mol. The B3LYP systematically underestimate the classical barrier heights and predict reasonable values for the geometries and frequencies of CH3OH and C2H5OH. The results show that the studied DFTs have strengths and weaknesses which are somewhat complementary. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Molecular one‐electron properties using the multireference Hartree–Fock CI method
Authors: Sobrinho A. M. C. , Nascimento M. A. C. , de Andrade M. D. , Malbouisson L. A. C.
Published: June 2008

The recently introduced multireference Hartree–Fock configuration interaction (MRHFCI) method has been applied to the calculation of the dipole moment of the LiH, BH, FH, CO, and H2O molecules. The results obtained indicate that MRHFCI wave functions, much more compact but of the same quality of the orthogonal full CI ones, can provide better dipole moments than the corresponding full CI wave functions. The value of the dipole moments obtained with the MRHFCI wave functions is quite insensitive to the choice of the HF references but the same is not true for the electronic energy. Therefore, further studies are necessary to develop a criterion for selecting a set of HF references which could provide the best values of energy and dipole moment. Also, it would be important to verify if other one‐electron properties can be computed with the same degree of accuracy obtained for the dipole moments. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Solvation of 5‐fluorouracil in supercritical CO2
Authors: Furlan Ana C. , Skaf Munir S.
Published: June 2008

The solvation properties of 5‐fluorouracil in supercritical carbon dioxide (SC‐CO2) is investigated by means of molecular dynamics computer simulations using a force field that treats all atoms explicitly. Solvation shell distribution functions and solvent density maps around the solute were computed at different supercritical temperatures in the range 308–328 K and densities varying from 0.117 to 0.94 g/cm3. At the lowest density, we detect a strongly inhomogeneous local density augmentation effect manifested as the clustering of solvent molecules above and below the solute molecular plane and around its carbonyl and NH groups. The free‐energy benefit for a CO2 molecule to be in the first solvation shell relative to the bulk is roughly twice the thermal energy at such conditions. The distribution of the relative orientation of CO2 with respect to the solute suggests that local bond multipolar solute–solvent interactions are responsible for the solvent density enhancement in these systems. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Enhanced bioremediation using whey powder for a trichloroethene plume in a high‐sulfate, fractured granitic aquifer
Authors: Mora Rebecca H. , Macbeth Tamzen W. , MacHarg Tara , Gundarlahalli Jagadish , Holbrook Holly , Schiff Paul
Published: June 2008

An in situ bioremediation (ISB) pilot study, using whey powder as an electron donor, is being performed at Site 19, Edwards Air Force Base, California, to treat groundwater contaminated with trichloroethene (TCE) via anaerobic reductive dechlorination. Challenging site features include a fractured granitic aquifer, complex geochemistry, and limited biological capacity for reductive dechlorination. ISB was conducted in two phases with Phase I including one‐and‐a‐half years of biostimulation only using whey powder and Phase II including biostimulation with buffered whey powder and bioaugmentation. Results of Phase I demonstrated effective distribution of whey during injections resulting in depletion of high concentrations of sulfate and methanogenesis, but acid production due to whey fermentation and limited buffering capacity of the aquifer resulted in undesirable impacts to pH. In addition, cis‐1,2‐dichloroethene (cis‐1,2‐DCE) stall was observed, which correlated to the unsuccessful growth of native Dehalococcoides populations. Therefore, Phase II included the successful buffering of whey powder using bicarbonate, which mitigated negative pH effects. In addition, bioaugmentation resulted in successful transport of Dehalococcoides populations to greater than 50 feet away from the injection point four months after inoculation. A concomitant depletion of accumulated cis‐1,2‐DCE was observed at all wells affected by bioaugmented Dehalococcoides. © 2008 Wiley Periodicals, Inc.