bluuebunny/crossref_metadata_2025 huggingface dataset:
Aberrant methylation of EphA7 in human prostate cancer and its relation to clinicopathologic features
Authors: Guan Ming , Xu Chong , Zhang Fanglin , Ye Chuanzhong
Published: September 2008

EphA7 is a member of Eph/ephrins family and play diverse roles in carcinogenesis. The aim of our study was to investigate functional and structural alterations of EphA7 in prostate cancer and determine if those findings correlate with the clinicopathologic features of prostate cancer. Forty‐eight prostate carcinomas, 31 benign prostate hyperplasias, 5 normal prostate tissues and 3 prostate cell lines (LNCaP, DU145 and PC‐3) were examined with quantitative RT‐PCR, methylation‐specific PCR and immunohistochemistry. Downregulation or loss of EphA7 mRNA expression was detected in 23 of 48 (47.9%) prostate carcinomas, and 2 of 31 (6.5%) hyperplasias. Methylation of the EphA7 promoter region was present in 20 of 48 (41.7%) of carcinomas and 6 of 31 (19.3%) hyperplasias, respectively. Immunostaining analysis showed EphA7 protein was absent in 10 of 30 (33.3%) carcinoma samples available and 8 of them (80.0%) exhibited hypermethylation. The frequency of EphA7 methylation was higher in cancer patients with higher Gleason score. Treatment of DU145 cells harboring methylation with 5‐aza‐2′‐deoxycytidine reactivated expression of EphA7. Ectopic expression of EphA7 in DU145 cells did not suppress cell growth but inhibited colony formation. Our study provides evidence that epigenetic inactivation of EphA7 may be involved in prostate carcinogenesis. © 2008 Wiley‐Liss, Inc.
The MUC1 oncoprotein as a functional target: Immunotoxin binding to α/β junction mediates cell killing
Authors: Rubinstein Daniel B. , Karmely Maya , Pichinuk Edward , Ziv Ravit , Benhar Itai , Feng Ningping , Smorodinsky Nechama I. , Wreschner Daniel H.
Published: September 2008

MUC1, a heavily glycosylated mucin, has generated considerable interest as a target for tumor killing because of its overexpression in malignancies. Full‐length MUC1 (MUC1/TM) is proteolytically cleaved after synthesis generating α and β subunits, which specifically bind in a noncovalent interaction. Although the β chain remains on the cell surface, the α chain binds in an on‐and‐off interaction. Most anti‐MUC1 antibodies (Abs) described to date recognize epitopes within the highly immunogenic α‐chain tandem repeat. Because the α‐chain is shed, such Abs are sequestered and fail to reach MUC1‐expressing cells. Immunizing with cDNA encoding MUC1/TM and the spliced MUC1/X isoform from which the tandem repeat has been deleted yielded antibodies to the MUC1 α/β junction. Pseudomonas toxin PE38 linked to polyclonal anti‐MUC1 α/β junction Abs both bound and killed MUC1‐positive malignant cells. Monoclonal DMC209 binds the MUC1 α/β junction in both MUC1/X and MUC1/TM. When injected into SCID mice xenotransplanted with human breast cancer MDA‐MB‐231, monoclonal DMC209 showed significant in vivo tumor‐suppressive activity. The MUC1/X α/β junction presents a biologically‐significant target in MUC1‐expressing malignancies because (i) antibodies directed against cell‐bound α/β junction epitopes reach the intended cellular target, (ii) antibodies to junction epitope are internalized into cells, (iii) anti α/β junction antibodies can effectively kill high MUC1‐expressing cancer cells as antibody‐toxin conjugates and (iv) antibodies targeting the MUC1 cell‐bound α/β junction results in tumor suppression in vivo. Our results indicate that cell‐bound MUC1 α/β junction, unlike shed alpha chain, represents a highly effective moiety for targeting and killing MUC1‐expressing malignancies. © 2008 Wiley‐Liss, Inc.
Starch and albumin mixture as replacement fluid in therapeutic plasma exchange is safe and effective
Authors: Agreda‐Vásquez Gladys P. , Espinosa‐Poblano Irma , Sánchez‐Guerrero Sergio A. , Crespo‐Solís Erick , Cabrera‐Vásquez Siram , López‐Salmorán Josefa , Barajas Josefina , Peñaloza‐Ramírez Paula , Tirado‐Cárdenas Nelly , Velázquez Antonio
Published: September 2008

Therapeutic plasma exchange (TPE) is an effective treatment in Myasthenia gravis (MG) and Guillain‐Barré syndrome (GBS) and 5% human albumin is the replacement fluid of choice; however, it is expensive. More recently, it has been suggested that starch is a safe and cheaper choice to human albumin. Objective: To evaluate our 5‐year experience using 3% hydroxyethyl starch (HES) and 5% human albumin mixture, as replacement fluid in TPE for these diseases. Materials and methods: Retrospective study carried out from January 2001 through September 2006. We included those patients with MG and GBS undergoing TPE. We analyzed clinical outcome (CO) and adverse events (AE) and our results were compared with a previous study which included similar patients undergoing TPE using just 5% human albumin. Results: Thirty‐one procedures were carried out in 26 patients, a total of 147 TPE sessions. In the group of MG we had 57% complete responses (CR) and 86% overall response (OR) while in the group of GBS we had 40% CR and 60% OR. When we analyzed our CO with the previous study no statistical differences were found. Mean processed plasma volume (PPV) was 4.2 in MG and 5.5 in GBS. Twenty patients had AE, being hypotension and catheter dysfunction the most frequent ones, while tachycardia, hypertension and paresthesias were statistically more frequent in the HES/albumin group. Conclusions: TPE with a mixture of 3% HES and 5% human albumin is as effective and safe as 5% human albumin alone for patients with these diseases. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Progressive recruitment of Runx2 to genomic targets despite decreasing expression during osteoblast differentiation
Authors: Pregizer Steven , Baniwal Sanjeev K. , Yan Xiting , Borok Zea , Frenkel Baruch
Published: September 2008

The mRNAs encoding Runx2, a master osteoblast transcription factor, and its target gene Osteocalcin (OC), are commonly used as markers of osteoblast differentiation. We found that while OC mRNA levels do indeed increase during development of the osteoblast phenotype in MC3T3‐E1 cultures, Runx2 mRNA levels surprisingly decrease. Neither translational control of Runx2 (based on Western analysis) nor regulation of its DNA‐binding ability (assessed by electrophoretic mobility shift assay) could explain the unexpected opposite patterns of Runx2 and OC expression. Instead, a series of chromatin immunoprecipitation (ChIP) assays during osteoblast differentiation revealed that early on, when Runx2 protein amount and DNA‐binding activity are maximal, it is practically absent from the OC promoter. At later stages, Runx2 is recruited to the OC promoter while Runx2 mRNA, protein, and in vitro DNA binding progressively decrease. We also followed Runx2 occupancy at a novel genomic target discovered by ChIP‐Chip analysis of cells in which the OC promoter is maximally occupied. The results revealed that Runx2 is recruited to this locus and to the OC promoter with a remarkably similar temporal pattern. These observations highlight a mechanism that restrains Runx2‐mediated transcriptional control by confining its access to genomic targets to a narrow window of time. The need for such stringent control is consistent with the severe consequences of Runx2 over‐expression in vivo. J. Cell. Biochem. 105: 965–970, 2008. © 2008 Wiley‐Liss, Inc.
Isolation and characterization of porcine adult muscle‐derived progenitor cells
Authors: Wilschut Karlijn J. , Jaksani Sridevi , Van Den Dolder Juliette , Haagsman Henk P. , Roelen Bernard A.J.
Published: September 2008

Here, we report the isolation of progenitor cells from pig skeletal muscle tissue fragments. Muscle progenitor cells were stimulated to migrate from protease‐digested tissue fragments and cultured in the presence of 5 ng/ml basic fibroblast growth factor. The cells showed a sustained long‐term expansion capacity (>120 population doublings) while maintaining a normal karyotype. The proliferating progenitor cells expressed PAX3, DESMIN, SMOOTH MUSCLE ACTIN, VIMENTIN, CD31, NANOG and THY‐1, while MYF5 and OCT3/4 were only expressed in the lower or higher cell passages. Myogenic differentiation of porcine progenitor cells was induced in a coculture system with murine C2C12 myoblasts resulting in the formation of myotubes. Further, the cells showed adipogenic and osteogenic lineage commitment when exposed to specific differentiation conditions. These observations were determined by Von Kossa and Oil‐Red‐O staining and confirmed by quantitative RT‐PCR analysis. In conclusion, the porcine muscle‐derived progenitor cells possess long‐term expansion capacity and a multilineage differentiation capacity. J. Cell. Biochem. 105: 1228–1239, 2008. © 2008 Wiley‐Liss, Inc.
MicroRNAs in embryonic stem cells
Authors: Wang Yulei , Keys David N. , Au‐Young Janice K. , Chen Caifu
Published: September 2008

The unique properties of embryonic stem cells (ESCs) to self‐renew indefinitely or to differentiate to any cell type have great potential for clinical applications in regenerative medicine. MicroRNAs (miRNAs) are emerging as important regulators of post‐transcriptional gene expression and have been implicated as crucial elements in regulating ESCs. Here, we review recent progresses in characterizing the role of miRNAs in the maintenance and development of ESCs. J. Cell. Physiol. 218: 251–255, 2009. © 2008 Wiley‐Liss, Inc.
Modeling and Simulation of Liquid Phase Propylene Polymerizations in Industrial Loop Reactors
Authors: de Lucca Eneida A. , Filho Rubens Maciel , Melo Príamo A. , Pinto José Carlos
Published: September 2008

Liquid phase tubular loop polymerization reactors are widely used in the polyolefin industries because of their capabilities to promote high mixing of reactants in the reaction vessel and to allow for high heat transfer rates with the cooling jacket due to their high aspect ratio. Previous works on this subject focused on the modeling of the polymerization system, but only a few compared their results with real industrial data. A literature review about the propylene production in loop reactors shows that the validation of a distributed model with actual industrial data is yet to be presented. A distributed mathematical model is presented for industrial liquid phase loop polypropylene reactors and validated with actual industrial data for the first time. The model is able to represent the dynamic trajectories of production rates, MFI and XS values during grade transitions within the experimental accuracy. The model indicates that the polymer quality can change significantly along the reactor train and that manipulation of feed flow rates can be successfully used for production of more homogeneous polymer products.
Estimating Reactivity Ratios From Triad Fraction Data
Authors: Hauch Emma , Zhou Xiaoqin , Duever Thomas A. , Penlidis Alexander
Published: September 2008

Reactivity ratio estimation is a non‐linear estimation problem. Typically, reactivity ratios are estimated using the instantaneous copolymer composition equation, otherwise known as the Mayo‐Lewis model, based on low conversion (<5%) copolymer composition data. However, there are other instantaneous models, which can be used to estimate reactivity ratios, such as the instantaneous triad fraction equations. The aim of this paper is to determine the potential improvement in reactivity ratio estimates when triad fraction data is used in place of and in combination with copolymer composition data. The interest in using triad fraction data in parameter estimation, stems from the fact that there are a greater number of responses measured (six triad fractions) compared to composition leading to data with theoretically more information content. In principle this should lead to reactivity ratio estimates having less uncertainty. In this study, the parameter estimates are obtained by employing the error in variables model (EVM), assuming a multiplicative error structure. Several case studies involving published literature data for different copolymer systems are presented. As the case studies demonstrate in general more precise estimates can be obtained from triad fraction data. Combining the triad fraction with composition data leads to little additional improvement. However, discrepancies arise between reactivity ratios estimated from composition data compared with those obtained from triad fraction data depending upon the copolymer system. Those copolymer systems exhibiting more heterogeneity due to phase separation during polymerization may be showing more discrepancy.
Microemulsion Polymerization Modeling Based on the Experimental Conversion Trend and its Derivative
Authors: López‐Serrano F. , López‐Aguilar J. E. , Mendizábal E. , Puig J. E. , Álvarez J.
Published: September 2008

In this work, the microemulsion polymerization modeling problem is addressed with an integrodifferential approach. The procedure was applied to experimental data, previously presented, on the microemulsion polymerization of hexyl methacrylate (C6MA) and styrene (STY). It was found that: (i) the nucleation rate is not linear with time, as assumed before, (ii) a vitreous effect is observed even in reactions where the polymer's glass transition temperature is lower than the reaction temperature, (iii) radical entry to polymer particles and coagulation among particles are negligible, (iv) the rate decrease interval is also caused by a reduction of active sites, (v) a mechanism in which micelles provide monomer to living particles was detected, and (vi) a simple three‐parameter mechanistic model was obtained, capable of describing the studied systems.
Coagulation of Carboxylic Acid‐Functionalized Latexes
Authors: Santos Adélia , Santos Alexandre F. , Sayer Cláudia , Araújo Pedro H. H. , Fortuny Montserrat
Published: September 2008

In the present work, the stability of particles produced by emulsion polymerization and stabilized by carboxylic acid groups was studied from turbidity measurements. To achieve this, a number of copolymerization runs was carried out under different reaction conditions, including the use of different carboxylic monomers. Partitioning analyses using conductimetric and potentiometric titrations were performed in order to assess the distribution of carboxylic monomers among the main phases of the produced latexes. Additionally, the stability and coalescence of particles were measured by turbidimetry in a diluted latex considering either the presence or not of the anionic surfactant sodium lauryl sulfate. Coalescence of particles was provoked in the latex samples at different temperatures by addition of an aliquot of a concentrated solution of electrolyte. The influence of surfactant, temperature and type of carboxylic acid group on the particle stability was investigated.
Molecular Architecture of Non‐Linear Polymers: Kinetic Modeling and Experimental Characterization of the System Methyl Methacrylate + Ethylene Glycol Dimethacrylate
Authors: Trigo Ivone M. R. , Gonçalves Miguel A. D. , Dias Rolando C. S. , Costa Mário Rui P. F. N.
Published: September 2008

A general kinetic approach allowing the prediction of the molecular architecture of non‐linear polymers is applied to the study of the copolymerization of methyl methacrylate (MMA) with ethylene glycol dimethacrylate (EGDMA). Dynamic predictions of molecular weight distributions, sequence length distributions and mean square radius of gyration are possible before and after gelation. A set of experiments concerning the copolymerization of MMA and EGDMA was carried out in toluene solution at 60 °C for which classic radical kinetics is a good approximation. The time evolution of key polymer properties was followed using a SEC system with a refractive index detector coupled with MALLS allowing the determination of absolute weight average molecular weight and apparent molecular size distributions as well as z‐average radius of gyration. Special focus was given to assess the influence of the initial amount of cross‐linker on the dynamics of the non‐linear structure build‐up of these products. A kinetic scheme comprising 23 different chemical species and 76 chemical reactions was used in the modeling studies of this chemical system. Most of the kinetic parameters used in the simulations have been collected from previous studies. For experiments at low monomer conversion (up to about 0.5) a good agreement between predictions and experimental measurements is observed for molecular weights and z‐average radius of gyration by fitting a small number of parameters describing gel effect (with a conversion dependent but chain length independent termination rate parameter) and the relative propagation on pendant double bonds. However, predicted values of weight‐average molecular weights and z‐average radius of gyration before gelation are too low at higher monomer conversions with non‐linear systems. The likely cause is the presence of intramolecular reactions which should not be neglected in these circumstances.
Preparation of Hybrid Nanocapsules
Authors: Ni K. , Bourgeat‐Lami E. , Sheibat‐Othman N. , Shan G. , Fevotte G.
Published: September 2008

Hybrid nanoparticles with a polystyrene core and a hybrid copolymer shell were used to produce hybrid nanocapsules by dissolving the polystyrene core from the previously elaborated core‐shell particles. Following previous works, the core‐shell particles were prepared by emulsion polymerization of styrene and subsequent addition of γ‐methacryloxy propyl trimethoxy silane (MPS) to produce the shell by copolymerization reaction of MPS with the residual styrene. Core extraction was performed by diluting the core‐shell particles in an excess of tetrahydrofuran (THF). Two procedures were investigated to separate the dissolved polymer chains from the nanocapsules. In the first procedure, the polymer was isolated by successive centrifugation and redispersion in THF, whereas in the second procedure, the free polymer chains were removed by dialysis. The polymer molecular weight was optimized in order to promote dissolution of the polymer chains and allow them to diffuse through the shell.
Initialization of RAFT Agents with Different Leaving Groups – Determination of the Transfer Coefficients
Authors: Drache Marco , Schmidt‐Naake Gudrun
Published: September 2008

The leaving group of the initial RAFT agent is one key factor during the initialization period of the RAFT polymerization. Benzyl‐, Phenylethyl‐ and Cumyl Dithiobenzoate RAFT mediated bulk polymerization of styrene at 120 °C was investigated by direct measurement of the concentration of the RAFT agent and determination of the molecular weight in the initial phase of the RAFT polymerization using Size Exclusion Chromatography (SEC). The initialization period can be described by means of two transfer coefficients that are determined by the stability of the free‐radical leaving group. By means of a Monte Carlo simulation the RAFT initialization process was characterized and the transfer coefficients from the experimental data were determined.
Structure elucidation and 1H/13C NMR spectral assignments of four trabectedin related compounds
Authors: Vermeulen Wim , Filliers Walter , García Carmen , Manzanaro Sonia , Montalvo David , Polanco Concepción , Spillemaeckers Frank , Van Hoof Bart , Winderickx Guido , Somers Ivan , Rodriguez‐Campos Ignacio
Published: September 2008

This article presents the structure elucidation of four new compounds, formed during the hemisynthetic preparation of trabectedin, an anti‐tumor natural product from Ecteinascidia turbinata. We report herein on the use of UV, MS and NMR spectroscopic data along with 1H and 13C spectral assignments obtained by means of 1D and 2D homo‐ and heteronuclear NMR techniques. Copyright © 2008 John Wiley & Sons, Ltd.
Prenylated isoflavones from Flemingia philippinensis
Authors: Li Hua , Yang Meihua , Miao Jianhua , Ma Xiaojun
Published: September 2008

Two new prenylated isoflavones, named flemiphilippinins E and F, were isolated from the roots of Flemingia philippinensis, together with six known ones. The structures of the above compounds were established by spectroscopic methods. Flemiphilippinins E and F were identified as 5,4′‐dihydroxy‐8‐(3,3‐dimethylallyl)‐6″,6″‐dimethyl‐5″‐(1,1‐dimethylallyl) pyrano(2″,3″:7,6)isoflavone and 5,4′‐dihydroxy‐4″,4″,5″‐trimethyl‐4″,5″‐dihydrofurano(2″,3″:7,8) isoflavone, respectively, by a combination of HR‐EI‐MS, 1H NMR, 13C NMR, HMQC, HMBC, and NOESY spectra. Copyright © 2008 John Wiley & Sons, Ltd.
MRI retinovascular studies in humans: research in patients with diabetes
Authors: Trick Gary L. , Edwards Paul A. , Desai Uday , Morton Paula E. , Latif Zahid , Berkowitz Bruce A.
Published: September 2008

Purpose

To review existing applications of MRI for detecting blood–retinal barrier (BRB) damage and retinal oxygenation response abnormalities in patients with diabetes and highlight new information available from such applications.

Methods

BRB studies were accomplished using dynamic contrast‐enhanced MRI, and the retinal oxygenation response studies were accomplished by monitoring changes in the MRI signal associated with hyperoxic provocation. Participants were patients with diabetes and macular edema, with either no detectable or mild to moderate background retinopathy, as well as non‐diabetic individuals of similar age (controls). Single‐slice FLASH images were obtained using a Siemens Sonata, 1.5 T together with a Siemens ‘Loop Small’ surface coil fixed in place over the eye. Time‐dependent changes in image contrast in the pre‐retinal vitreous were quantified, and differences between patients and controls were assessed statistically.

Results

The BRB breakdown studies showed a significant difference in the temporal evolution of the MRI signal enhancement post‐contrast injection between the controls and the patients with diabetic macular edema. The retinal oxygenation studies revealed a supernormal oxygenation response in the pre‐retinal vitreous in patients with diabetes who had no evidence of retinopathy, as well as in patients with background diabetic retinopathy. A nasal–temporal asymmetry in the evolution of retinal oxygenation response was found in patients with diabetes that was not present in healthy subjects.

Conclusions

These studies show that subtle differences in retinovascular function between patients with diabetes and non‐diabetic individuals, including changes that occur in advance of the clinical appearance of diabetic retinopathy, can be detected with MRI. These results, together with previous extensive preclinical data, establish MRI as a powerful non‐invasive method for measuring spatial and temporal changes in the same key retinovascular metrics in both animals and humans. Wide application of these techniques for diagnosis and evaluation of treatment efficacy in a variety of human retinopathies, including diabetic retinopathy, is expected. Copyright © 2008 John Wiley & Sons, Ltd.
The application of client‐centred occupational therapy for Korean children with developmental disabilities
Authors: Kang Dae Hyuk , Yoo Eun Young , Chung Bo In , Jung Min Ye , Chang Ki Yeon , Jeon Hye Seon
Published: September 2008

The aim of this paper was to investigate the effectiveness of client‐centred occupational therapy using the Canadian Occupational Performance Measure (COPM) and the Assessment of Motor and Process Skills (AMPS). Eight girls and 23 boys from Korea, with developmental disabilities and from 3 to 10 years of age participated in this study. Each child participated in 20 to 24 sessions of client‐centred occupational therapy. Both the COPM and the AMPS change scores demonstrated statistically significant improvement (p < 0.01) in occupational performance. Significant correlations were found between COPM – Performance and AMPS – Motor skills (rs = 0.64, p < 0.05), and COPM – Satisfaction and AMPS – Process skills (rs = 0.62, p < 0.05) in a group positive towards client‐centred occupational therapy. The COPM was a valuable tool in guiding and measuring the client‐centred occupational therapy for children with developmental disabilities. The small sample size of 31 children limits the generalizability of the study's results. Future research needs to use a larger and more diverse sample of children to further validate the effectiveness of client‐centred occupational therapy. Copyright © 2008 John Wiley & Sons, Ltd.
Preparation and characterization of polyaniline/MMT conductive composites
Authors: Liu Chenxiang , Zhou Yuanyuan , Li Song , Li Lei , Yu Min
Published: September 2008

Polyaniline/montmorillonite (PAn/MMT) composite material has been prepared through chemical‐oxidative polymerization by using NH4S2O8 as the oxidant, and it was found that both the composites have inorganic and organic material characteristics and many outstanding performance through the copolymerization coupling of MMT and polyaniline. Infrared spectroscopy (FT‐IR), thermogravimetric analysis (TGA), X‐ray diffraction (XRD), and transmission electron microscopy (TEM) are used to characterize the composition and structures of composite materials, as well as test the conductivity of composite materials through a four‐probe technique. The preparation conditions of PAn/MMT conducting composites are optimized. The optimal conditions have been identified for the reaction time, amount of oxidizer, concentration of HCl, and the amount of MMT. Besides, the results show that when the reaction lasts for 8 hr in the ice bath, the amount of MMT is 0.4 g/5 ml An, the mole ratio of oxidant to aniline is 1, and the concentration of hydrochloric acid is 2 M, the composite had the largest conductivity up to 11.5 S/cm. In addition, we also did an elemental analysis of the composite mechanism of PAn/MMT composites. Copyright © 2008 John Wiley & Sons, Ltd.
Structural and vibrational study of 2‐(2′‐furyl)‐1H‐imidazole
Authors: Ledesma A. E. , Brandán S. A. , Zinczuk J. , Piro O. E. , González J. J. López , Altabef A. Ben
Published: September 2008

The 2‐(2′‐furyl)‐1H‐imidazole (1) has been prepared and characterized using infrared, Raman, and multidimensional nuclear magnetic resonance spectroscopies. Two conformations of this species obtained by rotation of 180°, approximately, around the CC inter‐ring bond are detected. Likewise, the crystal and molecular structure of1has been analyzed by X‐ray diffraction methods and it evidenced that both conformations are present in the lattice with equal occupancy and linked in alternate way to the NH‐‐‐N bonded polymeric chains along the crystal [101] direction. Theoretical calculations have been carried out by employing the density functional theory (DFT)/B3LYP method, in order to optimize the geometry in gas phase of both conformers and to support the assignments of the vibrational bands of1to their normal modes. For a complete assignment of the compound, DFT calculations were combined with Pulay's SQMFF methodology in order to fit the theoretical frequency values to the experimental one. The nuclear magnetic resonance spectrum observed for1is successfully compared with the calculated chemicals shifts at B3LYP/6‐311++G** level of theory for the two conformers. Furthermore, natural bond orbital (NBO) analysis and topological (AIM) calculations for an oligomer, containing three alternated units of the NH‐‐‐N bonded chain found in the crystal, reveals the characteristics of the hydrogen bonds present in the polymeric structure. Copyright © 2008 John Wiley & Sons, Ltd.
Exploring preferential association of laponite and cloisite with soft and hard segments in TPU‐clay nanocomposite prepared by solution mixing technique
Authors: Mishra A. K. , Nando G. B. , Chattopadhyay S.
Published: September 2008

Thermoplastic polyurethane (TPU) is a versatile polymer exhibiting many engineering applications. In this article, two varieties of clay (Cloisite and Laponite RD) have been used to prepare TPU‐based nanocomposites. They differ in, chemical composition, hydrophobicity, aggregation tendency, and dispersibility in a particular solvent. A detailed investigation of the thermal, morphological, and rheological behavior reflects the affinity of Cloisite towards the soft segment, whereas it is the hard segment for modified Laponite. The maximum improvement in onset degradation temperature has been observed to be 17.5 and 8.3 °C for Cloisite and Laponite, respectively. Five percent Cloisite‐filled sample shows optimum storage modulus in the glassy region where as it is the 10% filled sample at the rubbery region. However, the trend remains indifferent both in rubbery and glassy regions for Laponite, and properties have been found optimum for 3% filled sample. To explore the behavior in the terminal and flow regions, dynamic rheological experiments were performed in low shear rate. Variation in dynamic rheological properties can be explained well on the basis of the combination of partly exfoliated, intercalated, and aggregated structures of the nano clay inside the TPU matrix, depending on their nature and preferential association with different segments. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2341–2354, 2008
Effects of chain configuration on UCST behavior in blends of poly(L‐lactic acid) with tactic poly(methyl methacrylate)s
Authors: Li Shu‐Hsien , Woo Eamor M.
Published: September 2008

Chain configuration influences phase behavior of blends of poly(methyl methacrylate) (PMMA) of different tactic configurations (syndiotacticity, isotacticity, or atacticity) with poly(L‐lactic acid) (PLLA). Blends system of sPMMA/PLLA is immiscible with an asymmetry‐shaped UCST at ∼250 °C. The phase behavior of the sPMMA/PLLA blend is similar to the aPMMA/PLLA blend that has been already proven in the previous work to exhibit similar UCST temperatures (230–250 °C) and asymmetry shapes in the UCST diagrams. On the other hand, the iPMMA/PLLA blend remains immiscible up to thermal degradation without showing any transition to UCST upon heating. The blend system with UCST, that is, sPMMA/PLLA, can be frozen in a state of miscibility by quenching to rapidly solidify from the homogeneous liquid at UCST, where the Tg‐composition relationship for the sPMMA/PLLA blend fits well with the Gordon‐Taylor Tg model with k = 0.15 and the blend's T leads to χ12 = −0.26 for the UCST‐quenched sPMMA/PLLA blend. Both parameters (k and χ) as characterized for the frozen miscible blend suggest a relatively weak interaction between the two constituents (sPMMA and PLLA) in the blends. The interaction strength is likely not strong enough to maintain a thermodynamic miscibility when the blend is at ambient temperature or any lower temperatures below UCST. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2355–2369, 2008
New insight into the crystallization behavior of poly(ethylene terephthalate)/clay nanocomposites
Authors: Guan Guohu , Li Chuncheng , Yuan Xuepei , Xiao Yaonan , Liu Xiaoqing , Zhang Dong
Published: September 2008

Crystallization behavior of poly(ethylene terephthalate) (PET)/clay nanocomposites has been investigated in terms of differential scanning calorimeter (DSC) analysis, polarizing optical microscopy (POM), and scanning electron microscopy (SEM) observation. The nanocomposites for investigation were prepared via in situ polycondensation. Crystalline morphologies were observed through POM and SEM. The nonisothermal and isothermal crystallization rates of different samples were determined for comparison based on DSC data. Secondary nucleation analysis was also performed based on bulk crystallization data derived from DSC analysis. The results revealed that nucleating abilities of montmorillonites (MMT) depended on the dispersion state of clay in matrix, the surface modification status, and the metallic derivatives released from MMT during in situ synthesis. The quantities of metallic elements released were measured by inductively coupled plasma (ICP) analysis. The results showed that the release of these metallic derivatives was also affected by surfactant molecules anchored on the surface of MMT. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2380–2394, 2008
Personality predicts prostate cancer treatment decision‐making difficulty and satisfaction
Authors: Orom Heather , Penner Louis A. , West Brady T. , Downs Tracy M. , Rayford Walter , Underwood Willie
Published: September 2008

Objective: Prostate cancer (PCa) patients often must decide between several treatment modalities considered equally efficacious, but associated with different benefits and side‐effects. For some, the decision‐making process can be difficult, but little is known about patient characteristics and cognitive processes that might influence the difficulty of such decisions. This study investigated the roles of dispositional optimism and self‐efficacy in PCa treatment decision‐making difficulty and satisfaction.

Methods: One hundred and twenty‐five patients with clinically localized PCa completed a mail‐in paper‐and‐pencil survey after they had made their treatment decision, but prior to treatment.

Results: After adjusting for covariates, optimism and treatment decision‐making self‐efficacy were associated with less difficulty and greater satisfaction with the treatment decision‐making process. Effects of optimism on difficulty and satisfaction were partially mediated by self‐efficacy for making the treatment decision.

Conclusions: Men with PCa and who are low in optimism may be at greater risk for treatment decision‐making difficulty and lack of treatment decision‐making satisfaction, in part, because they have lower confidence in their ability to make the decision compared with those who are more optimistic. As self‐efficacy perceptions are modifiable, consideration should be given to including self‐efficacy enhancing components as part of PCa treatment decision‐making interventions. Copyright © 2008 John Wiley & Sons, Ltd.
NFPA's hydrogen technologies code project
Authors: Rivkin Carl H.
Published: September 2008

This article discusses the development of National Fire Protection Association 2 (NFPA), a comprehensive hydrogen safety code. It analyses the contents of this document with particular attention focused on new requirements for setting hydrogen storage systems. These new requirements use computational fluid dynamic modeling and risk assessment procedures to develop requirements that are based on both technical analyses and defined risk criteria. The intent is to develop requirements based on procedures that can be replicated based on the information provided in the code document. This code will require documentation of the modeling inputs and risk criteria and analyses in the supporting information.

This article also includes a description of the codes and standards that address hydrogen technologies in general. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Procedural‐based controls in layer of protection analysis
Authors: Freeman Raymond “Randy”
Published: September 2008

The Center for Chemical Process Safety (CCPS) book on the LOPA (layer of protection analysis) methodology gives little credit for procedural controls. In batch operations, startups or process shutdowns, the procedural controls are often the only available means of controlling the potential hazards. This article presents a methodology for the evaluation of procedural‐based controls as potential independent layers of protection during a LOPA study. A checklist for the evaluation of procedural controls is presented as well as a few examples to demonstrate the methodology. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Improved process safety management and simple metrics
Authors: Chosnek Jack , Clifton Ricky
Published: September 2008

A Process Safety Management (PSM) system was recently implemented at Gulf Coast Waste Disposal Authority (GCWDA). This approach enabled management of increased process risks. These increased risks were brought about by the introduction of large quantities of oxygen for the processing of chemical waste and the destruction of emissions in Regenerative Thermal Oxidizers. This was a voluntary effort by GCWDA, since they do not fall under the OSHA PSM Standard (29 CFR 1910.119).

A tailored PSM system was developed that could comply with the OSHA Standard. This PSM system also included additional elements that are considered improvements on OSHA elements. These additional elements are utilized by some leading U.S. chemical manufacturing companies. These additional elements included Management Commitment, Management Review, Conduct of Operations and Continuous Improvement.

Simple metrics were created for selected PSM elements, in order to allow for continuous and proactive management review. These metrics supplemented periodic audits and replaced reliance on the common use of incident statistics.

This article will deal with the implementation of the PSM system from both the perspectives of the consultant that assisted in the implementation and the facility management that managed the implementation. The successes and some of the barriers for implementation in a small company will also be discussed, as well as the management success in the year after its implementation. © 2008 American Institute of Chemical Engineers Process Saf Prog, 2008
Energy transfer processes among emitters dispersed in a single polymer layer for colour tuning in OLEDs
Authors: Georgiadou D. G. , Vasilopoulou M. , Pistolis G. , Palilis L. , Dimotikali D. , Argitis P.
Published: September 2008

The energy transfer processes taking place in a single polymeric layer that enable the definition of the three primary colours (red, green and blue) in selected areas via photochemically induced emission tuning are discussed. The polymers used as hosts are two wide band gap polymers, PVK and a polyfluorenyl derivative. In the polymer matrix are dispersed the green emitter, 1‐(4′‐dimethyl‐aminophenyl)‐6‐phenyl‐1,3,5‐hexatriene (DMA‐DPH), the red emitter, 4‐dimethylamino‐4′‐nitrostilbene (DANS) and a photoacid generator (PAG). Upon irradiation, protons are released from the PAG and they react gradually with the two emitters, causing the blue shift of the green emitter fluorescence and the extinction of the red emitter fluorescence. Depending on the protonation extent, the relative concentrations of the emitters and the exposure dose the energy transfer processes occurring inside the matrix result in definition of different colour emitting areas. The understanding of the energy transfer processes with photoluminescence experiments is a necessary first step in order to rationalize the selection of suitable components enabling the definition of the three primary colours in OLEDs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tensile properties of shape memory alloy chiral honeycombs
Authors: Hassan M. R. , Scarpa F. , Mohamed N. A. , Ruzzene M.
Published: September 2008

The tensile properties of hexachiral honeycomb made of shape memory alloy (SMA) material are modelled and verified experimentally at different tensile loading and ambient temperature conditions. The numerical models describe the temperature‐pseudoelastic behaviour of the shape memory alloy materials constituted by Ni48Ti46Cu6 alloy. Parametric analysis on the Poisson's ratio effects over large strain deformation and temperature conditions are performed, as well as the analysis of the dependence of the honeycomb stress‐strain behaviour under uniaxial loading with temperature varying through the shape memory alloy phase transformation. Chiral SMA honeycomb samples are manufactured and tested under similar environmental conditions. The experimental results are compared with the numerical one, showing good convergence in terms of trends and overall quantitative values. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Responses of litter decomposition to temperature along a chronosequence of tropical montane rainforest in a microcosm experiment
Authors: He Xingbing , Zhang Peng , Lin Yonghui , Li Airong , Tian Xingjun , Zhang Qing‐He
Published: September 2008

We conducted a microcosm experiment for studying the decomposition of Altingia obovata leaf litter by the decomposer community at 20 and 30°C from three forest stands (namely a 35‐year‐old secondary forest, a 47‐year‐old secondary forest, and a primary forest) of a tropical montane rainforest. Our results showed that rank‐order of the litter decomposition among the three forest stands was not parallel to the stand age. At 20°C, the mass loss of A. obovata leaf litter from the primary forest was higher than those from the two secondary forests, of which the younger stand showed higher mass loss than did the older one. However, there were no differences in mass loss among these three stands at 30°C. The mass loss for the two secondary forest stands, but not for the primary forest stand, increased significantly from 20 to 30°C. The level of lignin decomposition among the three stands at 20°C corresponded to their forest stand age, i.e., the primary forest > the 47‐year‐old secondary forest > the 35‐year‐old secondary forest. A rise of 10°C in temperature significantly increased lignin decomposition for the two secondary forests, while the reverse was true for the primary forest. Carbohydrate decomposition was positively related to the temperature but not to the stand age. The different responses of litter decomposition to the forest stand age and temperature might be due to the differences in the microbial activities among the three forest stands.
Monitoring of Fat Content, Free Fatty Acid and Fatty Acid Profile Including trans Fat in Pakistani Biscuits
Authors: Kandhro Aftab , Sherazi S. T. H. , Mahesar S. A. , Bhanger M. I. , Talpur M. Younis , Arain Sarfraz
Published: September 2008

The fat contents of 12 brands of biscuits were extracted and evaluated for free fatty acids (FFA) and their fatty acid composition (FAC). The oil content and FFA varied from 13.7 to 27.6% and 0.2 to 1.0%, respectively. The FAC was analyzed by gas chromatography–mass spectroscopy with particular emphasis on trans fatty acids (TFA). Total saturated, unsaturated, cis‐monounsaturated and polyunsaturated fatty acids were determined in the range of 37.9–46.9, 53.0–62.0, 12.3–43.7 and 0.1–9.2%, respectively. The high amount of TFA was observed in all biscuit samples and varied from 9.3 to 34.9%. The quantity and quality of the lipid fraction of the biscuits indicated that the all analyzed biscuits are a rich source of fat, saturated fatty acids and trans fatty acids, consequently not suitable for the health of consumers. The high content of trans fatty acids and palmitic acid also indicated that blends of RBD palm oil and partially hydrogenated oil had been used in the biscuit manufacturing.
Le médium technique: objet et a priori
Authors: Despoix Philippe
Published: September 2008

Dans le fragment sur la musique, Max Weber réduit l'objet musical empiriquement descriptible au « médium technique » utilisé par chaque culture, dans la mesure où son analyse reste hétérogène aux valorisations esthétiques. Weber souligne que la reproduction phonographique du son constitue la condition de possibilité d'une analyse empirique du matériau musical, le point de départ d'une musicologie comparée moderne. Approche empirique et comparaison culturelle apparaissent ainsi reliées dans un chiasme « empirico-transcendental » qui fait du médium technique à la fois un objet et un a priori. L'article explicite ce choix méthodologique et ses conséquences pour une sociologie comparative de l'art.
La publication scientifique en ligne face aux lacunes du droit français
Authors: Gunthert André
Published: September 2008

Alors qu'Internet semblait pouvoir ouvrir des capacités inédites à l'édition scientifique, le durcissement législatif visant à protéger la propriété intellectuelle a compliqué l'exploitation des sources multimédia. En excluant l'application d'un usage raisonnable propre à l'exception pédagogique ou scientifique, le droit français se présente désormais comme une anomalie dans un contexte international de multiplication des ressources en ligne. Pour remédier à des conditions inadaptées, les pratiques sauvages se multiplient, symptôme de l'échec du dispositif existant.
Les moyens techniques de la science
Authors: Brian Éric
Published: September 2008

L'édition scientifique dans les disciplines qui concernent la Revue de synthèse a connu depuis une quinzaine d'années d'importantes transformations. L'article présente la formule à laquelle la Revue a finalement abouti. Elle combine une revue papier, une revue électronique, une collection patrimoniale et un site Internet expérimental de suppléments. Il propose un premier bilan des effets de ces transformations sur la production et la diffusion. Il tire des leçons de l'expérience multimédia tentée avec le présent numéro et le précédent.
Prospective prenatal serum screening for Down syndrome in Venezuela
Authors: Álvarez‐Nava Francisco , Soto Marisol , Morales‐Machín Alisandra , Rojas Alicia , Urdaneta Karelis , Cañizález Jenny
Published: September 2008

Objective

To assess the usefulness of triple‐marker screening for Down syndrome in Venezuela.

Method

Maternal serum concentrations of alpha fetoprotein (AFP), beta human chorionic gonadotropin (β‐hCG), and unconjugated estriol (uE3) were measured weekly in 3895 women from the 15th to the 20th week of pregnancy. Population‐specific likelihood ratios were determined and used to calculate the risk of fetal Down syndrome for each pregnancy.

Results

The median multiple of the median values for AFP, β‐hCG, and uE3 concentrations were 0.69, 2.10, and 0.67 for the affected pregnancies. The likelihood ratio for a positive result was 1:19. The detection and false‐positive rates were 69.23% and 5.8%.

Conclusion

These findings were consistent with reported data and therefore confirmed triple‐marker serum screening as effective and suitable for prenatal care in Venezuela. Latin American governments and Health Agencies should recommend offering this screening method to all pregnant women.
An interim revision of episcopal dates for the province of Canterbury, 850—950: part I
Authors: O'Donovan Mary Anne
Published: September 2008

This paper is offered in the hope that it will provide reliable evidence for those wishing to make use of episcopal dates during the century 850–950. The original editors of the Handbook of British Chronology were assured by experts that ‘until all the available charter-evidence had been critically sifted, it would be useless to try and revise the available lists of Anglo-Saxon bishops’, so they used for their lists the information available in W. Stubbs's Registrum Sacrum Anglicanum, 2nd ed. (Oxford, 1897) and W. G. Searle's Anglo-Saxon Bishops, Kings and Nobles (Cambridge, 1899). We are still far from the desired state of charter study, but a good deal has been done on this and related studies in the last few decades, and perhaps the time has come to look again at the bishops' dates. In many cases the episcopal witnesses can corroborate or impugn the genuineness of a charter, and it is sometimes the misfortune of the Anglo-Saxon historian, in using the appearance of a certain bishop to strengthen the validity of a charter, to find that the date of the bishop's episcopate is determined by the very charter in question. So the critical sifting of all the available charter evidence must include a study of episcopal dates – one cannot take place without the other.