bluuebunny/crossref_metadata_2025 huggingface dataset:
π‐Section tunable matching network with patterned ferroelectric thin film
Authors: Zhang X. Y. , Wang P. , Tan C. Y. , Ong C. K.
Published: September 2008

A prototype of a tunable impedance matching network in π‐configuration has been fabricated with ferroelectric varactors of patterned Barium‐Strontium‐Titanate Ba0.5Sr0.5TiO3 (BST) thin film. The matching circuit is designed based on a coplanar waveguide (CPW) transmission line and interdigital capacitors (IDC). The tunable impedance matching range and insertion loss are measured with varying voltage at the frequency range of 0.1–2 GHz. The insertion loss of designed circuit is 0.36 dB at 0.9 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3251–3254, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23942
Histopathological classification of childhood rhabdomyosarcoma: A report from the international society of pediatric oncology pathology panel
Authors: Caillaud J. M. , Gérard‐Marchant R. , Marsden H. B. , Unnik A. J. M. Van , Rodary C. , Rey A. , Flamant F.
Published: September 2008

Five hundred thirteen soft tissue tumours of childhood referred to the International Society of Pediatric Oncology (SIOP) Rhabdomyosarcoma study have been reviewed. The period covered was from January 1975 to December 1983. Three hundred thirty‐nine neoplasms were regarded as embryonal rhabdomyosarcoma. The histological diagnosis of all referred tumours is given, and a classification of rhabdomyosarcomas developed during the course of the study is described. The relationship between histological subtypes and aspects of clinical behaviour is presented. The classification is thought to be helpful in diagnosis and also in assessment of the likelihood of recurrence and/or metastasis of childhood rhabdomyosarcoma.
Allograft inflammatory factor‐1: A pathogenetic factor for vasculitic neuropathy
Authors: Broglio Laura , Erne Beat , Tolnay Markus , Schaeren‐Wiemers Nicole , Fuhr Peter , Steck Andreas J. , Renaud Susanne
Published: September 2008

Allograft inflammatory factor‐1 (AIF‐1) is a cytokine that plays a major role in the immune response and proliferative vasculopathy that occur during chronic allograft rejection. The purpose of this study was to characterize the cellular expression pattern and pathogenetic role of AIF‐1 in nerve biopsies from patients with vasculitic neuropathy. We performed immunohistochemistry in human nerve biopsies of 10 patients with vasculitic neuropathies (VASs), 6 with chronic inflammatory demyelinating polyneuropathies (CIDPs), 5 with noninflammatory axonal neuropathies (NIANs), and 3 control nerves (CNs). In the CIDP and VAS nerves, AIF‐1 expression was higher than in CN and NIAN nerves (P < 0.05). AIF‐1 was increased in the arterial walls of VAS compared with CIDP nerves (P < 0.05). Vascular smooth muscle cells in vasculitic nerve express AIF‐1 at a higher level compared with CIDP and NIAN. AIF‐1 plays a role in inflammatory nerve disease and vascular smooth muscle cell proliferation and may be a new molecular target for treatment. Muscle Nerve 38: 1272–1279, 2008
Long‐term intensive electrically stimulated cycling by spinal cord–injured people: Effect on muscle properties and their relation to power output
Authors: Duffell Lynsey D. , Donaldson Nick de N. , Perkins Tim A. , Rushton David N. , Hunt Kenneth J. , Kakebeeke Tanja H. , Newham Di J.
Published: September 2008

Inactivity and muscular adaptations following spinal cord injury (SCI) result in secondary complications such as cardiovascular disease, obesity, and pressure sores. Functional electrically stimulated (FES) cycling can potentially reduce these complications, but previous studies have provided inconsistent results. We studied the effect of intensive long‐term FES cycle training on muscle properties in 11 SCI subjects (mean ± SEM: 41.8 ± 2.3 years) who had trained for up to 1 hour/day, 5 days/week, for 1 year. Comparative measurements were made in 10 able‐bodied (AB) subjects. Quadriceps maximal electrically stimulated torque increased fivefold (n = 5), but remained lower than in AB individuals. Relative force response at 1 HZ decreased, relaxation rate remained unchanged, and fatigue resistance improved significantly. Power output (PO) improved to a lesser extent than quadriceps torque and not to a greater extent than has been reported previously. We need to understand the factors that limit PO in order to maximize the benefits of FES cycling. Muscle Nerve 38: 1304–1311, 2008
Sensory physiology assessed by evoked potentials in survivors of poliomyelitis
Authors: Prokhorenko Olga A. , Vasconcelos Olavo M. , Lupu Vitalie D. , Campbell William W. , Jabbari Bahman
Published: September 2008

Evidence suggests that sensory loss may occur in a proportion of patients affected by poliomyelitis. We hypothesize that sensory problems may be a lasting sequela in some polio survivors. Sensory pathways in polio survivors were evaluated clinically and electrophysiologically using sensory evoked potentials (SEPs). Patients with sensory deficits or abnormal SEPs were further evaluated by magnetic resonance imaging (MRI). Twenty‐two patients were studied. The mean age was 64.7 years (age range: 56–81 years). Clinically, sensory impairments were found in 4 patients. Upper limb SEPs were normal. Lower limb SEPs were abnormal in 10 patients. In 1 patient, clinical and electrographic findings correlated with a patch of atrophy in the spinal cord, as shown by MRI. Sensory derangements may be found in a proportion of aging polio survivors. SEP studies may add sensitivity when evaluating sensory function in this cohort. It remains unclear whether these sensory abnormalities are related to remote poliomyelitis. Further studies are necessary. Muscle Nerve 38: 1266–1271, 2008
Comparison of parametric and nonparametric reference data in motor unit potential analysis
Authors: Podnar Simon
Published: September 2008

For calculation of outlier reference intervals, by definition nonparametric statistics are applied, while for mean value reference intervals parametric or nonparametric statistics can be used. The aim of this study was to compare the mean value reference intervals and their sensitivity for diagnosis of myopathy. Quantitative concentric needle electromyography (EMG) of the biceps brachii muscle was performed using multi–motor unit potential (MUP) analysis. In 34 healthy subjects both parametric (mean ± 2SD) and nonparametric (2.5th–97.5th percentiles) reference intervals were calculated for mean values of MUP parameters, while for outliers nonparametric reference intervals (5th–95th percentiles) were calculated. Their sensitivity was tested in 29 patients with facioscapulohumeral muscular dystrophy. Nonparametric reference intervals were narrower than parametric intervals, which resulted in slightly higher sensitivities when combined with outlier limits (e.g., thickness = 86% and 83%, respectively). Muscle Nerve, 2008
Collateral reinnervation by the superior laryngeal nerve after recurrent laryngeal nerve injury
Authors: Hydman Jonas , Mattsson Per
Published: September 2008

This study investigates the role of the intact superior laryngeal nerve (SLN) in the reinnervation process of one of the laryngeal muscles, the posterior cricoarytenoid muscle (PCA), following recurrent laryngeal nerve (RLN) injury. Using a chronic RLN injury model in the adult rat, PCA reinnervation was assessed by retrograde double‐tracing techniques in combination with electrophysiology and immunohistochemistry of muscle sections. The results demonstrate that the PCA receives dual innervation from both laryngeal nerves even in the uninjured system. Functionally significant collateral reinnervation originates from intact SLN fibers following RLN injury, mainly due to intramuscular sprouting rather than by recruitment of more motor neurons. This may be important when choosing surgical and/or medical treatment for patients with RLN injury. Muscle Nerve 38: 1280–1289, 2008
A generic model of motor‐carrier fuel optimization
Authors: Suzuki Yoshinori
Published: September 2008

Fuel optimizers are decision models (software products) that are increasingly recognized as effective fuel management tools by U.S. truckload carriers. Using the latest price data of every truck stop, these models calculate the optimal fueling schedule for each route that indicates: (i) which truck stop(s) to use, and (ii) how much fuel to buy at the chosen truck stop(s) to minimize the refueling cost. In the current form, however, these models minimize only the fuel cost, and ignore or underestimate other costs that are affected by the models' decision variables. On the basis of the interviews with carrier managers, truck drivers, and fuel‐optimizer vendors, this article proposes a comprehensive model of motor‐carrier fuel optimization that considers all of the costs that are affected by the model's decision variables. Simulation results imply that the proposed model not only attains lower vehicle operating costs than the commercial fuel optimizers, but also gives solutions that are more desirable from the drivers' viewpoint. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008
Relationships between patient‐centered cancer nursing interventions and desired health outcomes in the context of the health care system
Authors: Radwin Laurel E. , Cabral Howard J. , Wilkes Gail
Published: September 2008

A non‐experimental longitudinal prospective study was conducted to examine the relationships between patient‐centered nursing interventions (PCNIs), system characteristics, patient characteristics, and desired health outcomes (DHOs) for 173 hematology‐oncology patients. Forty‐nine nurse participants provided system characteristics data. Confirmatory factor analyses yielded parsimonious scales to operationalize the variables. In the path model, one PCNI—individualization—was positively related to three subsequent DHOs: authentic self‐representation, optimism, and sense of well‐being. Two additional PCNIs—responsiveness and proficiency—were positively related to subsequent trust in nurses. PCNIs did not vary with patient race, ethnicity, age, gender, or educational level. Patient‐centeredness of care for cancer patients may be enhanced by quality improvement activities that measure and monitor these PCNIs and resultant outcomes. © 2008 Wiley Periodicals, Inc. Res Nurs Health 32:4–17, 2009
Phosphorylation of the oestrogen receptor α at serine 305 and prediction of tamoxifen resistance in breast cancer
Authors: Holm C , Kok M , Michalides R , Fles R , Koornstra RHT , Wesseling J , Hauptmann M , Neefjes J , Peterse JL , Stål O , Landberg G , Linn SC
Published: September 2008

Phosphorylation of oestrogen receptor α at serine 305 (ERαS305‐P) induces tamoxifen resistance in experimental studies, but does not influence response to other endocrine agents, such as fulvestrant. We evaluated ERαS305‐P using immunohistochemistry in 377 breast carcinomas from premenopausal participants of a randomized trial (n = 248) and patients with advanced disease (n = 129). Among the premenopausal patients, adjuvant tamoxifen improved recurrence‐free survival (RFS) for ERαS305‐P‐negative tumours (multivariate HR = 0.53, 95% CI 0.32–0.86, p = 0.010), but not for ERαS305‐P‐positive tumours (multivariate HR = 1.01, 95% CI 0.33–3.05, p = 0.99) (interaction p = 0.131). Notably, ERαS305‐P was not significantly associated with RFS in patients not treated with tamoxifen (multivariate HR = 0.64, 95% CI 0.30–1.37, p = 0.248), indicating that ERαS305‐P is a marker for treatment outcome rather than tumour progression. Given the direct experimental link between ERαS305‐P and tamoxifen resistance and these first clinical data suggesting that premenopausal patients with ERαS305‐P‐positive breast cancer are resistant to adjuvant tamoxifen, further research is encouraged to study whether alternative endocrine treatment should be considered for this subgroup. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Applying diagnostic criteria for type 1 von Willebrand disease to a pediatric population
Authors: Hyatt Sarah A. , Wang Wei , Kerlin Bryce A. , O'Brien Sarah H.
Published: September 2008

Background

Definitive diagnosis of type 1 von Willebrand disease (VWD) remains elusive in clinical practice. Both the International Society on Thrombosis and Haemostasis (ISTH) and the Hospital for Sick Children (HSC) have proposed diagnostic criteria for type 1 VWD, which include abnormal laboratory values, significant mucocutaneous bleeding history, and/or positive family history. The objective of this study was to apply ISTH and HSC criteria to a large pediatric population previously diagnosed with type 1 VWD. We hypothesized that a substantial number of patients would not meet these diagnostic criteria.

Procedure

We performed a retrospective medical record review of all type 1 VWD patients at a single children's hospital. Frequencies of fit for ISTH and HSC diagnostic criteria were calculated.

Results

Of 201 patients, 4.5% and 34% met the ISTH and HSC definitions, respectively. An additional 15% (ISTH) and 56% (HSC) met the definition of possible disease. For each definition, criteria for significant bleeding were most likely to be met, while criteria for abnormal laboratory values were least likely. When defined as simply VWF:Ag 5–20 IU/ml, as recently proposed by the ISTH, only 9% of patients met the definition of type 1 VWD.

Conclusions

ISTH criteria failed to identify the majority of children and adolescents who presented to medical attention with significant mucocutaneous bleeding. Further work is needed to develop diagnostic criteria with improved clinical validity in the pediatric setting. Pediatr Blood Cancer 2009;52:102–107. © 2008 Wiley‐Liss, Inc.
Effects of storage aging on the cure kinetics of T700/BMI prepregs for advanced composites
Authors: Guo Zhan‐Sheng
Published: September 2008

The effects of room temperature aging on the cure kinetics of a bismaleimide (BMI) matrix prepreg have been characterized by different time and storage conditions. The study has focused on the stability of BMI matrix carbon fiber prepregs, when exposed to controlled environmental conditions before being used in composite manufacturing. The effects of aging on reactivity, glass transition temperature, and process window have been investigated by differential scanning calorimetrer through dynamic and isothermal tests. A theoretical kinetic model for epoxy matrix prepregs, developed in previous studies, has been applied to the cure of both aged and virgin BMI matrix. The model is able to satisfactorily describe the effect of processing variables such as temperature and degree of cure during the curing of the composite under different conditions (curing temperature and heating rate). The effects of diffusion‐controlled phenomena on the cure kinetics, associated with changes in glass transition temperature as a function of the degree of cure, have been taken into account in the formulation of an nth‐order kinetic model. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Pressure window analysis for thin laminated composites in autoclave process
Authors: Li Min , Li Yanxia , Zhang Zuoguang , Gu Yizhuo
Published: September 2008

The curing temperature, pressure, and curing time have significant influence on finished thermosetting composite products. The external pressure and the time of pressure application are two major factors affecting the laminate thickness, fiber volume fraction, and void content. Based on the resin flow/fiber compaction model and corresponding program developed by our group, the genetic algorithm is accepted to design the pressure window for the consolidation of thin laminate. The objective of the optimization is to find the time of pressure application that achieves the desired average fiber volume fraction under given pressure. The pressure windows are analyzed for S‐2 glass fiber/5228 and T700S/5228 laminates with unidirectional and bidirectional lay‐up. It is found that no special viscosity region can be defined as pressure window for many factors affecting the consolidation process. The fiber and lay‐up type largely affect the time of pressure application. For laminates with the same fiber and lay‐up type, the fiber distribution is not much influenced by pressure cycle. The uneven degree of fiber distribution is larger for the fiber bed having higher deformation properties. With the genetic algorithm optimization system, the time of pressure application can be gotten quickly. It is helpful for the improvement of composite parts quality, reduction of the fabrication cost. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Study on superabsorbent composite. XX. Effects of cation‐exchanged montmorillonite on swelling properties of superabsorbent composite containing sodium humate
Authors: Zheng Yian , Wang Aiqin
Published: September 2008

In this work, the effects of different cation‐exchanged montmorillonite on water absorbency of poly(acrylic acid‐co‐acrylamide)/montmorillonite/sodium humate (PAA‐AM/MMT/SH) superabsorbent composite were systematically investigated under the same preparation conditions. The superabsorbents doped with different cation‐exchanged montmorillonite were characterized by Fourier‐transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy technologies. Swelling behaviors of developing superabsorbent composite in various cationic saline solutions (NaCl, CaCl2, and FeCl3) were also investigated. The water absorbencies of superabsorbent composite with 20 wt% MMT and 30 wt% SH are 638, 723, 682, and 363 g g−1 in distilled water for incorporating natural Na+‐MMT, Li+‐exchanged MMT, Ca2+‐exchanged MMT, and Al3+‐exchanged MMT, respectively. The results showed that the cation‐exchange process had some obvious influences on final water absorbency of superabsorbent composite. NaCl, CaCl2, and FeCl3 solutions did not alter the swelling characteristics of the superabsorbent materials at a concentration of less than 0.01 mM, however, a concentration of greater than 0.1 mM caused a collapse in the swelling curves. The excellent swelling‐reswelling‐swelling behavior and lower swelling rate testified that Al3+‐exchanged MMT can act as an assistant crosslinker in the polymeric network. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Cure kinetics and conductivity of rigid rod epoxy with polyaniline as a curing agent
Authors: Fu Tiezhu , Liu Jia , Wang Jing , Na Hui
Published: September 2008

The samples of rigid rod epoxy resin (4,4′‐diglycidyl (3,3′,5,5′‐tetramethylbiphenyl) epoxy resin (TMBP)) with different weight contents of polyaniline (PANI) as a curing agent were prepared. The kinetics of curing reaction between TMBP and PANI was analyzed by dynamic differential scanning calorimetry in the temperature range of 25–300°C. The results showed that the heat of cure reaction of TMBP/PANI sample with 10 wt% PANI was larger than those of others. The active energies with different curing conversions of TMBP/PANI sample with 10 wt% PANI were calculated by iso‐conversional method using the Coats‐Redfern approximation. The results showed that the activation energy was dependent on the degree of conversion. The morphology of the cured samples was detected by scanning electron microscopy measurements. The relationship between morphology and conductivity of cured samples was researched. The conductivities increased from 2.7 × 10−4 to 9.5 × 10−4 S/cm with the increase of PANI from 5 to 20 wt% in cured samples. The thermal stabilities of cured TMBP/PANI samples were examined by thermogravimetric analysis. The results showed that the cured TMBP/PANI can be promising to use as a conducting adhesive. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Rheological behavior and theoretical modeling of uniaxial elongational flow properties of polypropylene/layered silicate nanocomposites
Authors: Lee Seung Hwan , Kim Seong Yun , Youn Jae Ryoun
Published: September 2008

Rheological behaviors of polypropylene/layered silicate nanocomposites were investigated in both shear and uniaxial elongational flows. They were analyzed by using the K‐BKZ constitutive equation with two damping functions, for example, the WD‐FÖ and PSM‐LT models in transient and steady elongational viscosities. Although pure PP matrix and uncompatibilized nanocomposite did not show the strain hardening, compatibilized nanocomposite showed outstanding strain‐hardening behavior due to three‐dimensional network structure. Predictions of WD‐FÖ and PSM‐LT models gave good agreement with the experimental results at low elongational rate region. However, the elongational viscosity calculated with the WD‐FÖ model did not predict the steady‐state value and diverged to infinity when
$\dot{\varepsilon} {\lambda}_{\bf max}\ {\geq}\ {\bf 1}$. The PSM‐LT model offered good description on transient and steady elongational viscosities even at higher elongational rates as well as on strong strain‐hardening behavior of compatibilized nanocomposites. Through the numerical analysis, using the K‐BKZ model with two types of damping functions, it was found that the PSM‐LT model was superior to that of the WD‐FÖ model in rheological modeling of PP/layered silicate nanocomposites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Investigation of oxygen barrier properties of organoclay/HDPE/EVA nanocomposite films prepared using a two‐step solution method
Authors: Dadfar S.M. Reza , Ramazani S.A. Ahmad , Dadfar S.M. Ali
Published: September 2008

In this article, oxygen barrier properties of nanocomposite films composed of organoclay (OC), high‐density polyethylene (HDPE), and ethylene vinyl acetate (EVA) copolymer have been investigated. The nanocomposite films whose EVA forms a dominant fraction were prepared using the solution method. The dispersion of the OC in the HDPE/EVA blend was improved through taking two‐step procedure in the preparation of nanocomposite. First, the OC and EVA were dissolved in chloroform. Then, the resulting product, after evaporating most of the solvent, along with HDPE was dissolved in xylene. The obtained nanocomposite films underwent a number of tests in order to examine their barrier properties including X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The results showed that OC/HDPE/EVA nanocomposites are intercalated and partially exfoliated. Furthermore, from the TEM micrographs, the organoclay experimental aspect ratio was found. Also, the O2 permeability through the films was evaluated, which showed that adding both OC and HDPE to EVA leads to a remarkable increase in the barrier properties of EVA films. Finally, by using the gas permeation results and existing permeation theories, the organoclay theoretical aspect ratio was predicted. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Piezo and dielectric properties of PHB–PZT composite
Authors: Malmonge J.A. , Malmonge L.F. , Fuzari G.C. , Malmonge S.M. , Sakamoto W.K.
Published: September 2008

Flexible piezoelectric composite films made of poly(3‐hydroxybutyrate) (PHB) in powder form and lead zirconate titanate (PZT) ceramic powder were obtained by mixing both powders and pressing at 180°C. The effect of PZT on PHB crystallization was investigated using differential scanning calorimetry (DSC). The relative dielectric constant and dielectric loss factor were analyzed by dielectric spectroscopy and the α‐relaxation of amorphous phase of PHB was observed. After suitable polarization, the composite film displayed piezoelectric activity indicating the possibility of using that material as a sensor. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Effect of temperature on hygroscopic thickness swelling rate of composites from lignocellolusic fillers and HDPE
Authors: Najafi Abdollah , Kazemi Najafi Saeed
Published: September 2008

Effect of temperature on hygroscopic thickness swelling rate of lignocellolusic fillers/HDPE (high density polyethylene) composites was investigated. The composites were manufactured using a dry blend/hot press method. In this method, powder of plastic and dried powder of lignocellolusic material were mixed in high‐speed mixer and then the mixed powder were pressed at 190°C. Lignocellolusic fillers/HDPE composites panels were made from virgin and recycled HDPE (as plastic) and wood sawdust and flour of rice hull (as filler) at 60% by weight filler loadings. Nominal density and dimensions of the panels were 1 g/cm3 and 35 × 35 × 1 cm3, respectively. Thickness swelling rate of manufactured wood plastic composites (WPCs) were evaluated by immersing them in water at 20, 40, and 60°C for reaching a certain value where no more thickness was swelled. A swelling model developed by Shi and Gardner [Compos. A, 37, 1276 (2006)] was used to study the thickness swelling process of WPCs, from which the parameter, swelling rate parameter, can be used to quantify the swelling rate. The results indicated that temperature has a significant effect on the swelling rate. The swelling rate increased as the temperature increased. The swelling model provided a good predictor of the hygroscopic swelling process of WPCs immersed in water at various temperatures. From the activation energy values calculated from the Arrhenius plots, the temperature had less effect on the thickness swelling rate for the composites including wood sawdust compared with the rice hull as filler and the composites including recycled compared with the virgin HDPE as plastic. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Temperature and strain rate dependences of yield stress of polypropylene composites reinforced with carbon nanofibers
Authors: Bao S.P. , Tjong S.C.
Published: September 2008

Polypropylene (PP) nanocomposites filled with 0.1, 0.3, 0.5, and 1.0 wt% carbon nanofiber (CNF) were prepared via melt compounding in a twin‐screw extruder followed by injection molding. The effects of CNF additions on the structure, mechanical and tensile yielding behavior of PP were investigated. TEM and SEM observations showed that CNFs were dispersed uniformly within PP matrix. Tensile test showed that the yield strength and Young's modulus of PP were improved considerably by adding very low CNF loadings. The reinforcing effect of CNF was also verified from the dynamic mechanical analysis. Impact measurement revealed that the CNF additions were beneficial to enhance the impact toughness of PP. The yield stress of the PP/CNF nanocomposites was found to be strain rate and temperature dependent. The yielding responses of PP/CNF nanocomposites can be described successfully by the Erying's equation and a reinforcing index n. The structure and mechanical property relationship of the nanocomposites is discussed. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Dynamic mechanical study of epoxy, epoxy/glass, and glass/epoxy/wood hybrid composites aged in various media
Authors: Ghasemzadeh Shahab , Haddadi‐Asl Vahid , Kajorncheappunngam Somjai , GangaRao Hota V.S. , Gupta Rakesh K.
Published: September 2008

It was proposed and subsequently established that wrapping of red oak wood crossties with epoxy impregnated glass fiber composites will impart longer service life and better stiffness and strength characteristics to these hybrid ties than conventional ones and will help them better withstand environmental extremes. The objective was to understand the degrading effects of aqueous (distilled water), saline (NaCl), acidic (HCl), and alkaline (NaOH) solutions, as well as accelerated aging and freeze/thaw cycling environments on the dynamic and static mechanical properties of these hybrid materials (i.e., wood, wrapped with fiber reinforced resin) and their components. Also micrographs of composite samples, obtained through scanning electron microscopy (SEM), were studied to determine the failure mechanism of composite specimens aged in different environments. Results showed that immersion in aging media lowered the glass transition temperature (Tg) and enhanced apparent phase separation in the samples because of polymer plasticization. In water immersion, the Tg and the stiffness increased with time owing to continued resin curing. At ambient temperature, sustained load had little effect on the mechanical behavior of the aged samples. The extent of degradation was the least for samples aged in salt solution. Soaking in room‐temperature acid solution was most damaging to pure red oak wood samples. Six‐cycle aging did not damage the neat resin or the hybrid samples, whereas it damaged pure wood specimens. Therefore, the composite wrapping around the wood core of the hybrid sample protected it sufficiently, thereby preventing damage to the hybrid specimen during the aging process. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Characterization and properties of activated nanosilica/polypropylene composites with coupling agents
Authors: Lin Ong Hui , Md Akil Hazizan , Ishak Z.A. Mohd
Published: September 2008

In this work, nanosilica/polypropylene composites containing 1 wt% of silica nanoparticles were prepared by melt mixing in a Thermo Haake internal mixer. Prior compounding, nanosilica was subjected to surface activation using sodium hydroxide (NaOH) solution. The effectiveness of the activation process was evaluated by measuring the amount of hydroxyl groups (OH) on the surface of nanosilica via titration method and supported by FTIR analysis. Two coupling agents namely 3‐aminopropyl triethoxysilane (APTES) and neopentyl (diallyl)oxy, tri(dioctyl) phosphate titanate (Lica 12) were used for surface treatment after activation process. The mechanical properties of polypropylene matrix reinforced with silica nanoparticles were determined by tensile and impact test. Hydroxyl groups on the nanosilica surface played an important role in enhancing the treatment with silane coupling agents. To increase the amount of hydroxyl groups on the nanosilica surface, the optimum concentration of NaOH is 1 mol%. Tensile strength, tensile modulus, and impact strength of nanosilica/PP composites improved with activation process. As the coupling agent is concerned, APTES coupling agent is more pronounced in enhancing the mechanical properties of the composites when compared with Lica 12 coupling agent. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Prevalence of scleroderma in Spain: an approach for estimating rare disease prevalence using a disease model
Authors: Villaverde‐Hueso A. , de la Paz M. Posada , Martín‐Arribas M. C. , Sánchez‐Valle E. , Ramírez‐González A. , Biairdi P.
Published: September 2008

Purpose

To estimate scleroderma prevalence in Spain.

Methods

As no data were available for Spain we used reported scleroderma incidence (Silman's study on UK and Alamanos' on Greece), scleroderma cause‐specific mortality, obtained through the National Institute of Statistics (codes included in M34 of the International Classification of Diseases, 10th revision) in Spain and remission data. Estimates were applied to the Spanish population and to all‐cause mortality for 2004, broken down by age group and gender. Estimators were assumed to follow a Poisson distribution. DisMod‐II software was used for this purpose.

Results

Estimated prevalence was 0.23 and 0.71 cases per 10 000 people for men and women, respectively, based on UK incidence, and 0.28 and 2.58 cases per 10 000 people, respectively, based on Greek incidence. Estimated age at disease onset ranged from 50 to 58 years among men and from 52 to 55 among women, according to UK and Greek data, respectively. Mean duration of the disease was estimated to be in the range of 17–20 years for men and 19–20 for women.

Conclusions

DisMod‐II is useful for obtaining, modelling and confirming variability ranges of prevalence found in literature. It also provides information for orphan drug designation and for supporting public health decisions regarding rare diseases. Copyright © 2008 John Wiley & Sons, Ltd.
A simplified method to determine the 3D orientation of an injection molded fiber‐filled polymer
Authors: Régnier G. , Dray D. , Jourdain E. , Le Roux S. , Schmidt F. M.
Published: September 2008

In short‐fiber reinforced composites, it is widely accepted that the fiber orientation plays an important role on their overall physical and thermomechanical properties. To predict the properties of such composite materials, a full 3D fiber orientation characterization is required. A variety of destructive and nondestructive techniques have been developed, but all the methods have the same common point that they are very tedious and time consuming. Knowing that the fiber orientation induced by the flow remains mainly in the flow plane, an easier method has been performed for injection molded fiber‐filled polymers. It is based on the simple 2D SEM image analysis of a specific 45°‐oblique section plane. Then, the indetermination of fiber orientation from an ellipse mark analysis does not exist anymore. This novelty also turns out to be much more accurate. To achieve measurements over large composite samples, the method has been fully automated. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Modeling of heat transfer in rotational molding
Authors: Banerjee S. , Yan W. , Bhattacharyya D.
Published: September 2008

Rotational molding is a process for manufacturing hollow or open‐sided plastic products using a rotating mold subjected to heating and then cooling. The process is attractive for the production of stress‐free objects at a competitive cost. In this article, a modified model for heat transfer in rotational molding is proposed, which assumes that the heat transfer at the mold‐powder interface is because of convection, whereas the powder particles are heated up by conduction. Heat transfer through the mold–air contact is also included. A source‐based formulation is used for modeling the layer‐by‐layer nonisothermal deposition of plastic. The reduced heat transfer due to warpage is calculated by using a modified heat transfer coefficient. Good overall agreement is found between the cycle times as predicted by the model and the experimental data. The model is then used for calculating the cycle time for particulate composites, based on their effective properties. A reduction in the cycle time is observed in the case of reinforced composites. This is attributed to the increase in thermal conductivity of the particulate composites and the reduced mass fraction of the polymer. Numerical calculations of the cycle time for the glass‐bead reinforced composites are found to be in good agreement with the experimental results. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Mixed‐mode subcritical crack growth in orthotropic polymers
Authors: Wu Chunhui , Mantell Susan C. , Davidson Jane H.
Published: September 2008

A semi‐empirical model of mixed‐mode sub‐critical crack propagation is presented for orthotropic polymers subjected to continuous loading. The model considers a combination of opening and shearing propagation modes. Optical measurement of crack propagation in an orthotropic liquid crystalline polymer film for orientation angles, which define the orientation of the loading to the extrusion direction, of 45 and 90° provides the empirical constants required by the model. The model is validated by comparison of predicted and measured crack propagation at 30, 60, and 75°. The impact of orientation angle on crack propagation is significant. A critical angle is identified at which the crack propagation rates for the opening and shearing modes are equivalent. For orientation angles less than the critical angle the crack growth is dominated by the shearing mode. For orientation angles greater than the critical angle, the crack growth is dominated by the opening mode. For the liquid crystalline polymer film tested, the critical angle is 52.6°. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Effects of polyol molecular weight on properties of benzoxazine–urethane polymer alloys
Authors: Rimdusit Sarawut , Mongkhonsi Tharathon , Kamonchaivanich Pakawan , Sujirote Kuljira , Thiptipakorn Sunan
Published: September 2008

Recently, a new thermoset resin namely benzoxazine (BA) resin has been developed. The polymer possesses several outstanding properties, such as, ease of synthesis, low viscosity, near‐zero shrinkage, lack of by‐product upon curing, high thermal stability, and high mechanical property. Moreover, the benzoxazine resins can be alloyed with various types of resins because of the various function groups in their structure. In this work, urethane elastomer (PU) is used to enhance toughness of the polybenzoxazine. The effects of polyol molecular weights on the properties of BA: PU polymer alloys are investigated. The experiment reveals that the similar curing peaks of the matrices at various polyol molecular weights, with the same urethane mass fraction, in the resin mixtures are obtained. The glass transition temperature increases from 160°C of polybenzoxazine to 240–245°C in the 70:30 BA:PU system. In addition, the char yield increases when the higher molecular weight of polyol is added. The flexural modulus of polybenzoxazine decreases from 6.2 GPa to be in the range of 2.2–2.8 GPa when 30 wt% of PU is presented in the alloys. Furthermore, the synergism with ultimate flexural strength is observed in the 90:10 BA:PU alloy for all molecular weights of the polyol used. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Melting behavior and isothermal crystallization kinetics of nylon 11/EVOH/dicumyl peroxide blends
Authors: Wang Biaobing , Ding Zhengya , Hu Guosheng
Published: September 2008

Nylon 11/ethylene‐vinyl alcohol/dicumyl peroxide (DCP) blends were prepared using a single‐screw extruder. The melting behavior and isothermal crystallization kinetics were investigated using differential scanning calorimetry. The reorganization of nylon 11 crystals is strongly hindered owing to cocrosslinking phenomena. The analysis of the crystallization kinetics demonstrated that the Avrami equation well described the isothermal crystallization process of the primary stage. The spherulites growth kinetics parameters and fold surface free energy were also evaluated. The experimental results confirmed that the presence of DCP increased the crystallization rate. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Kinetics of the thermal decomposition reaction of diethylketone cyclic triperoxide in acetone–toluene and acetone–1‐propanol binary solvent mixtures
Authors: Iglesias Mariángeles , Eyler Nora , Cañizo Adriana
Published: September 2008

The thermal decomposition reaction of diethylketone triperoxide (DEKT) ca. 0.02 M was studied in binary mixtures of acetone–toluene and acetone–1‐propanol at 150 °C. Products of DEKT thermolysis in solution, detected by GC analysis, were diethylketone, bibenzyl and butane. The reactions were explored by GC at different solvent compositions and in each case the reactions followed a pseudo first order kinetic law, up to at least 90% peroxide conversion. The rate coefficient value of the reaction is affected by the solvent properties, showing an increase in the kobs values with increases in the polarity of the solvent mixture in acetone–toluene systems. Changes in the rate coefficient values are probably caused by the presence of the apolar toluene solvent, which dominates the preferential solvation around the DEKT molecule through non‐specific interactions. In acetone–1‐propanol mixtures the solvation effect is slightly dominated by the specific interactions between the 1‐propanol and a polar intermediate specie represented by the biradical, initially formed. The rate coefficient value increases ca. 6% in the mixture with 0.1 mole fraction of 1‐propanol in comparison with the value in pure acetone; but no more changes in rate coefficient values are observed when the amount of the alcohol increases. The critical state of the reaction (intermediate biradical) is preferentially solvated by the 1‐propanol instead of acetone, but in mixtures of different composition, it is not possible to detect any effect on the reactivity for homolytic rupture of the OO bond. Copyright © 2008 John Wiley & Sons, Ltd.
Fully aromatic poly(ether ketone)s bearing macrocycle pendants: Synthesis and crosslinking
Authors: Yue Xigui , Zhu Ming , Zhang Haibo , Liu Baijun , Wang Yishan , Jiang Zhenhua
Published: September 2008

This study reports a method to prepare fully aromatic poly(ether ketone) thermosets. The cyclization of 2′,5′‐dimethoxy[1,1′‐biphenyl]‐2,5‐diol and a difluoro monomer was carried out under pseudo high dilution condition. Two types of fully aromatic poly(ether ketone)s with macrocycle were successfully prepared by copolymerization of macrocycle of aryl ether ketone containing hydroxyphenyl groups, 4,4′‐(hexafluoroisopropylidene)diphenol (HFBPA), and 4,4‐difluorobenzophenone. The obtained copolymers have high molecular mass, good solubility, and high glass transition temperatures in the presence of CsF, the crosslinking reaction of copolymers occurred and afforded fully aromatic thermoset poly(aryl ether ketone)s by ring‐opening reaction driven by entropy. After crosslinking, these copolymers show much higher glass transition temperatures, excellent thermal stability, and better mechanical strength. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7002–7010, 2008
Aliphatic poly(ester‐carbonate)s bearing amino groups and its RGD peptide grafting
Authors: Hu Xiuli , Chen Xuesi , Xie Zhigang , Cheng Haibo , Jing Xiabin
Published: September 2008

This article deals with (1) synthesis of novel cyclic carbonate monomer (2‐oxo [1,3]dioxan‐5‐yl)carbamic acid benzyl ester (CAB) containing protected amino groups; (2) ring‐opening copolymerization of the cyclic monomer with L‐lactide (LA) to provide novel degradable poly(ester‐carbonate)s with functional groups; (3) removal of the protective benzyloxycarbonyl (Cbz) groups by catalytic hydrogenation to afford the corresponding poly(ester‐co‐carbonate)s with free amino groups; (4) grafting of oligopeptide Gly‐Arg‐Gly‐Asp‐Ser‐Tyr (GRGDSY, abbreviated as RGD) onto the copolymer pendant amino groups in the presence of 1,1′‐carbonyldiimidazole (CDI). The structures of P(LA‐co‐CA/RGD) and its precursor were confirmed by 1H NMR analysis. Cell experiments showed that P(LA‐co‐CA/RGD) had improved adhesion and proliferation behavior. Therefore, the novel RGD‐grafted block copolymer is promising for cell or tissue engineering applications. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7022–7032, 2008
Synthesis and self‐assembly of tadpole‐shaped organic/inorganic hybrid poly(N‐isopropylacrylamide) containing polyhedral oligomeric silsesquioxane via RAFT polymerization
Authors: Zhang Weian , Liu Li , Zhuang Xiaodong , Li Xiaohui , Bai Jinrui , Chen Yu
Published: September 2008

Aminopropylisobutyl polyhedral oligomeric silsesquioxane (POSS) was used to prepare a POSS‐containing reversible addition‐fragmentation transfer (RAFT) agent. The POSS‐containing RAFT agent was used in the RAFT polymerization of N‐isopropylacrylamide (NIPAM) to produce tadpole‐shaped organic/inorganic hybrid Poly(N‐isopropylacrylamide) (PNIPAM). The results show that the POSS‐containing RAFT agent was an effective chain transfer agent in the RAFT polymerization of NIPAM, and the polymerization kinetics were found to be pseudo‐first‐order behavior. The thermal properties of the organic/inorganic hybrid PNIPAM were also characterized by differential scanning calorimetry. The glass transition temperature (Tg) of the tadpole‐shaped inorganic/organic hybrid PNIPAM was enhanced by POSS molecule. The self‐assembly behavior of the tadpole‐shaped inorganic/organic hybrid PNIPAM was investigated by atomic force microscopy and dynamic light scattering. The results show the core‐shell nanostructured micelles with a uniform diameter. The diameter of the micelle increases with the molecular weight of the hybrid PNIPAM. Surprisingly, the micelle of the tadpole‐shaped inorganic/organic hybrid PNIPAM with low molecular weight has a much bigger and more compact core than that with high molecular weight. © Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7049–7061, 2008
Reducing Water Permeability while Maintaining Transparency of PET: A Plasma Immersion Ion Implantation Study
Authors: Mizuno Keisuke , Gan Bee K. , Kondyurin Alexey , Bilek Marcela M. M. , McKenzie David R.
Published: September 2008

PET sheets were surface‐modified by ion implantation from argon, nitrogen and hydrogen plasmas. The ion implantation was found to cause carbonization and cross‐linking, improving gas barrier properties against water vapor. The barrier effectivity improved with increased implanted ion fluence. The permeability changes and optical bandgap both depend on the ion species used during implantation. The lowest permeability was obtained using argon. For practical applications, the balance between gas barrier properties and photopic transparency is important. Our results show that argon implantation yields the lowest permeability with best retention of photopic transparency.

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Influence of Impinging Ion Energy on the Bonding and Mechanical Characteristics of DLC Films Deposited by Microwave ECR Plasma CVD
Authors: Singh Sujit , Pandey Mukesh , Kishore Ramaswamy , Chand Naresh , Dash Sitaram , Tyagi Ashok , Patil Dinkar
Published: September 2008

DLC films were deposited on Si(111) substrates using CH4/Ar gas and microwave ECR plasma CVD processes. The energy of the ions impinging on the substrate during deposition was varied by changing the rf self bias voltage developed on the substrate. The bonding characteristics of the deposited films were investigated using FTIR and Raman spectroscopy, and mechanical properties were measured by nanoindentation and nanoscratch tests. The results obtained from different characterization techniques are correlated and explained on the basis of existing growth models for DLC films. Our studies indicate that the energy of the ions impinging on the substrates has a strong influence on the bonding characteristics and mechanical properties of the films.

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Influence of different assignment conditions on the determination of symmetric homodimeric structures with ARIA
Authors: Bardiaux Benjamin , Bernard Aymeric , Rieping Wolfgang , Habeck Michael , Malliavin Thérèse E. , Nilges Michael
Published: September 2008

The ambiguous restraint for iterative assignment (ARIA) approach for NMR structure calculation is evaluated for symmetric homodimeric proteins by assessing the effect of several data analysis and assignment methods on the structure quality. In particular, we study the effects of network anchoring and spin‐diffusion correction. The spin‐diffusion correction improves the protein structure quality systematically, whereas network anchoring enhances the assignment efficiency by speeding up the convergence and coping with highly ambiguous data. For some homodimeric folds, network anchoring has been proved essential for unraveling both chain and proton assignment ambiguities. Proteins 2009. © 2008 Wiley‐Liss, Inc.