bluuebunny/crossref_metadata_2025_split huggingface dataset:
Composites based on jute fibers and phenolic matrices: Properties of fibers and composites
Authors: Razera I. A. T. , Frollini E. 
Published: November 2003

AbstractComposites based on phenolic matrices and both untreated and alkali and ionized air–treated jute fibers were prepared. Different fiber lengths and fiber content were used to reinforce the phenolic matrices. The jute fibers were characterized with respect to lignin, holocellulose, ash, and humidity contents and also to the crystallinity index. The mechanical properties of fibers were investigated by means of tensile analysis and the morphology by SEM. The untreated and treated jute fiber–reinforced composites were characterized as to water absorption. The mechanical property and morphological aspects of the composites were evaluated by impact strength and photomicrographs obtained from SEM. Among the jute fiber treatments considered in the present work, the treatment with a solution of 5% NaOH presented the best results because: (1) the fiber presented a higher tensile strength, and a larger percentage of elongation at break; (2) the composite reinforced with this fiber presented the highest impact strength results when this was the unique treatment (20% of fiber), as well as when it was combined with ionized air (30% of fiber); and (3) the composite that presented the lowest water uptake was that reinforced with this fiber. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1077–1085, 2004
Synthesis in inverse emulsion and associating behavior of hydrophobically modified polyacrylamides
Authors: Pabon Martial , Corpart Jean‐Marc , Selb Joseph , Candau Françoise 
Published: November 2003

AbstractAn inverse free‐radical emulsion polymerization technique was used to prepare copolymers of acrylamide and two different hydrophobic comonomers: N,N‐dihexylacrylamide (diC6) or N,N‐diphenylacrylamide (diPh). The products of the reaction were high molecular weight hydrophobically modified water‐soluble polymers (HMWSPs) encapsulated within water droplets dispersed in an organic medium. A comparison of the copolymer compositions prepared under different experimental conditions showed that the level of incorporation of diPh in the final copolymer depended strongly on its localization in the emulsion (aqueous or oil phase) and on the nature of the redox initiator pair (water‐soluble or oil‐soluble). The rheological properties of the HMWSPs in aqueous solution were investigated as a function of the comonomer content and the nature of the initiator, using steady‐flow experiments. The thickening properties were found to be directly correlated to the conditions of synthesis and were optimal when the initiator and the hydrophobic comonomer were located in two distinct phases. An examination of the viscosity as a function of shear rate showed that these solutions exhibit typical characteristics of hydrophobically associative polymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 916–924, 2004
Microhardness studies of PMMA/natural rubber blends
Authors: Mina M. F. , Ania F. , Baltá Calleja F. J. , Asano T. 
Published: November 2003

AbstractThe microhardness, H, of PMMA/natural rubber blends, prepared following the solution method has been investigated by means of the microindentation technique. Hardness changes are correlated with the variation of the glass transition temperature. The influence of temperature and degree of deformation on H were additionally examined. The inclusion of rubber particles in the PMMA matrix is shown to soften the blends. The variation of the micromechanical property at the phase boundary of polymer/rubber particle has been studied. Results reveal that H drastically drops at the interphase. In the case of the drawn materials, the indentation anisotropy (ΔH) is shown to gradually increase with the draw ratio, where ΔH is found to be higher for the PMMA/rubber blend than for the original PMMA. This result is explained by the higher orientation of the PMMA molecules near the periphery of stretched rubber particles. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 205–210, 2004
Phase morphology of PP/COC blends
Authors: Šlouf Miroslav , Kolařík Jan , Fambri Luca 
Published: November 2003

AbstractPhase morphology of polymer blends PP/COC, where PP is polypropylene and COC is a copolymer of ethene and norbornene, was characterized by means of scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM). PP/COC blends were prepared by injection molding and their morphology was studied for six different compositions (90/10, 80/20, 70/30, 60/40, 50/50, and 25/75 wt %). The intention was to improve PP properties by forming COC cocontinuous phase, which should impart to the PP matrix higher stiffness, yield stress, and barrier properties. Surprisingly enough, all studied blends were found to have fibrillar morphology. In the 90/10, 80/20, and 70/30 blends, the PP matrix contained fibers of COC, whose average diameter increased with increasing COC fraction. In the 60/40 blend, the COC component formed in the PP matrix both fibers and larger elongated entities with PP fibers inside. The 50/50 blend was formed by COC cocontinuous phase with PP fibers and PP cocontinuous phase with COC fibers. In the 25/75 blend, PP fibers were embedded in the COC matrix. In all blends, the fibers had an aspect ratio at least 20, were oriented in the injection direction, and acted as a reinforcing component, which was proven by stress–strain and creep measurements. According to the available literature, the fibrous morphology formed spontaneously in PP/COC is not common in polymer blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 253–259, 2004
Wood flour: A new filler for the rubber processing industry. II. Cure characteristics and mechanical properties of NBR compounds filled with corona‐treated wood flour
Authors: Vladkova T. G. , Dineff P. D. , Gospodinova D. N. 
Published: November 2003

AbstractCorona‐treated wood flour was evaluated as a filler for NBR (nitrile butadiene rubber) compounds by studying its influence on their cure characteristics and mechanical properties. The different operating conditions of the corona treatment, such as voltage and duration, which led to different degrees of surface etching, were observed by means of electron microscopy. Accumulation of different oxygen‐containing groups on the wood flour particles' surface was confirmed by means of ESCA. Wood flour–filled materials were thus obtained with varying final properties. The cure characteristics, mechanical parameters, and water adsorption of the composites were estimated to determine an optimum level of the wood flour surface modification. The corona treatment of the wood flour renders it into a semiactive filler. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 883–889, 2004
Melt flow indexer evidence of high‐temperature transitions in molten high‐density polyethylenes
Authors: Hussein Ibnelwaleed A. , Williams Michael C. 
Published: November 2003

AbstractA melt flow indexer (MFI) was used to investigate high‐temperature transitions in melts of high‐density polyethylene (HDPE). The MFI data were obtained in the range 190–230°C. These transitions were found in the MFI at about 210 and 225°C and reproduced in a Haake melt blender. Polystyrene was used in the blender experiment to demonstrate typical amorphous behavior. For HDPE melts, the MFI–temperature behavior and the torque–temperature data of the blender were found to be alternative images of the same anomalous temperature dependency in the range 210–225°C. Also, the Haake melt blender was able to reproduce the 150°C transition observed by Kolnaar and Keller in the extrusion of HDPE. Regardless of the simplicity of the MFI device, results are in agreement with our previous DSC findings. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1309–1313, 2004
Effect of coupling agent on the mechanical properties of fly ash–filled polybutadiene rubber
Authors: Alkadasi Nabil A. N. , Hundiwale D. G. , Kapadi U. R. 
Published: November 2003

AbstractFly ash, a waste productof thermal power stations generated in huge quantities, has been posing problems of its disposal. As such it contains a variety of inorganic oxides and is available in finely powdered form. Attempts have been made for its use as a filler in elastomers and plastics. It is important to note that fly ash used in in untreated form does not significantly enhance the mechanical properties of composites. In this work, fly ash treated with silane coupling agent (Si‐69) was used as a filler in polybutadiene rubber (PBR). The comparison of properties of composites filled with treated and untreated fly ash revealed that the composites with treated fly ash showed better reinforcing properties. Thus the silane coupling agent used here promoted adhesion between fly ash and the PBR. The improvement in mechanical properties in general and tensile properties (tensile strength, modulus 100% and modulus 200%, hardness) of the composites in particular were observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1322–1328, 2004
Properties of crosslinked casein/waterborne polyurethane composites
Authors: Wang Niangui , Zhang Lina , Lu Yongshang , Du Yuming 
Published: November 2003

AbstractWaterborne polyurethane (WPU) and casein (1 : 1 by weight) were blended at 90°C for 30 min, and then were crosslinked by adding 1–10 wt % ethanedial to prepare a series of sheets. Their structure and properties were characterized by using infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, dynamic mechanical analysis, and tensile testing. The results indicated that crosslinked blend sheets exhibited a certain degree of miscibility, and exhibited much higher tensile strength and water resistivity than did the WPU, casein, and the uncrosslinked blend from WPU and casein. When the ethanedial content was 2 wt %, the tensile strength and elongation at break of crosslinked sheets achieved 19.5 MPa and 148% in the dry state, and 5.0 MPa and 175% in the wet state, respectively. A 2 wt % content of ethanedial plays an important role in the enhancement of mechanical properties, thermal stability, and water resistivity of the blends of WPU and casein as a result of intermolecular crosslinking. This work provided a new protein plastic with good water resistivity. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 332–338, 2004
Influence of processing method on the exfoliation process for organically modified clay systems. I. Polyurethanes
Authors: Rhoney Ian , Brown Steven , Hudson Nicholas E. , Pethrick Richard A. 
Published: November 2003

AbstractThe influence of different processing methods on the nature of the dispersion achieved in the creation of a polyurethane nanocomposite is presented. The nanocomposites were produced using two different types of organically modified montmorillonite clays and a sample of fine particles of silicon nitride as a reference material. Rheological data were used to assess the nature of the dispersion achieved using the different processing methods. The nature of the dispersion produced was characterized using wide‐angle X‐ray scattering measurements of the finally cured products. Dynamic mechanical thermal analysis was used to investigate the effect of the incorporation of clay platelets into the matrix of the polymer. The high‐temperature modulus provides evidence of the interaction between the polymer and the clay platelets; however, surprisingly, the glass transition temperatures of the filled and unfilled materials were almost identical. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1335–1343, 2004
Characterization of two molluscan crystal‐modulating biomineralization proteins and identification of putative mineral binding domains
Authors: Michenfelder Martina , Fu Germaine , Lawrence Camille , Weaver James C. , Wustman Brandon A. , Taranto Laura , Evans John Spencer , Morse Daniel E. 
Published: November 2003

AbstractEthylenediamine‐tetraacetic acid extracted water‐soluble matrix proteins in molluscan shells secreted from the mantle epithelia are believed to control crystal nucleation, morphology, orientation, and phase of the deposited mineral. Previously, atomic force microscopy demonstrated that abalone nacre proteins bind to growing step edges and to specific crystallographic faces of calcite, suggesting that inhibition of calcite growth may be one of the molecular processes required for growth of the less thermodynamically stable aragonite phase. Previous experiments were done with protein mixtures. To elucidate the role of single proteins, we have characterized two proteins isolated from the aragonitic component of nacre of the red abalone, Haliotis rufescens. These proteins, purified by hydrophobic interaction chromatography, are designated AP7 and AP24 (aragonitic protein of molecular weight 7 kDa and 24 kDa, respectively). Degenerate oligonucleotide primers corresponding to N‐terminal and internal peptide sequences were used to amplify cDNA clones by a polymerase chain reaction from a mantle cDNA library; the deduced primary amino acid sequences are presented. Preliminary crystal growth experiments demonstrate that protein fractions enriched in AP7 and AP24 produced CaCO3 crystals with morphology distinct from crystals grown in the presence of the total mixture of soluble aragonite‐specific proteins. Peptides corresponding to the first 30 residues of the N‐terminal sequences of both AP7 and AP24 were generated. The synthetic peptides frustrate the progression of step edges of a growing calcite surface, indicating that sequence features within the N‐termini of AP7 and AP24 include domains that interact with CaCO3. CD analyses demonstrate that the N‐terminal peptide sequences do not possess significant percentages of α‐helix or β‐strand secondary structure in solution. Instead, in both the presence and absence of Ca(II), the peptides retain unfolded conformations that may facilitate protein–mineral interaction. © 2003 Wiley Periodicals, Inc. Biopolymers 70: 522–533, 2003
Spectroscopic study of permanganate oxidation reactions of oligonucleotides containing single base mismatches
Authors: Bui Chinh T. , Lambrinakos Andreana , Cotton Richard G. H. 
Published: November 2003

AbstractThe electrophoretic gel‐based chemical cleavage of the mismatch method gives an incomplete view of the DNA conformational changes induced by a single base mismatch. This spectroscopic study investigates the permanganate oxidation reactions with matched and mismatched DNA under constant and variable temperature conditions. The results, which include the oxidation levels, reaction patterns with isosbestic points, color changes, thermal spectra, spectroscopy derivative, and gel separation and melting temperatures, provide a fundamental background for identification of oligonucleotides containing single base mismatches by chemical means. © 2003 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 70: 628–636, 2003
Experimental evaluation of phospholipids and icodextrin in re-formation of peritoneal adhesions
Authors: Müller S A , Treutner K H , Anurov M , Titkova S , Oettinger A P , Schumpelick V 
Published: November 2003

Abstract

Background
The formation of further adhesions after adhesiolysis is a major problem. Not all agents that are supposed to reduce de novo adhesions can reduce further adhesion formation. The efficacy and safety of intraperitoneally applied phospholipids has been shown previously. This study evaluated the influence of phospholipids and icodextrin on adhesion re-formation.

Methods
In an experimental study on 60 Chinchilla rabbits adhesions were induced by standardized abrasion of defined areas of the ventral abdominal wall, the caecum and the ileum. Open adhesiolysis was performed 10 days later. The animals randomly received either 1·5 per cent phospholipids, 4 per cent icodextrin or Ringer's lactate intraperitoneally. Half of the animals in each group were killed after a further 10 days and the remainder at 20 days. Adhesion formation was assessed by computer-aided planimetry and histopathological examination.

Results
Phospholipids (10 days: P = 0·001; 20 days: P = 0·012) and icodextrin (10 days: P = 0·006; 20 days: P = 0·055) reduced adhesion re-formation after both intervals compared with Ringer's lactate controls.

Conclusion
Phospholipids and icodextrin were effective in preventing re-formation of adhesions.
Persistent increase in the incidence of abdominal aortic aneurysm in Scotland, 1981–2000
Authors: Best V A , Price J F , Fowkes F G R 
Published: November 2003

Abstract

Background
In the 1970s and 1980s, mortality and morbidity rates for abdominal aortic aneurysm (AAA) increased throughout the developed world. As AAAs are associated with similar risk factors to other cardiovascular diseases that have recently decreased in incidence, the incidence of AAA should show a similar declining trend.

Methods
Routinely collected data were obtained on all primary diagnoses of aortic aneurysm resulting in death or hospital discharge in Scotland between 1981 and 2000. Trends in the data were analysed according to sex and age, aneurysm site and type of hospital admission.

Results
Between 1981 and 2000, 42·3 per cent of the 10 822 deaths from aortic aneurysm in Scotland were attributed to the abdominal aorta. Age-adjusted mortality rates for AAA increased 2·6-fold from 2·62 deaths per 100 000 in 1981 to 6·82 per 100 000 in 2000. Hospital admissions for AAA also rose threefold, with increases in both elective admissions (from 3·05 to 7·80 per 100 000) and emergency admissions (from 7·44 to 11·23 per 100 000).

Conclusion
The incidence of AAA has increased over the past 20 years in Scotland. This is unlikely to be due simply to changes in detection and diagnosis, data inaccuracies, coding or ageing of the population. The incidence of both elective and emergency admission for AAA increased, suggesting that a genuine and persistent rise in the incidence of AAA has probably occurred.
Matrix metalloproteinase 2 and 9 activity in patients with colorectal cancer liver metastasis
Authors: Waas E T , Wobbes T , Lomme R M L M , DeGroot J , Ruers T , Hendriks T 
Published: November 2003

Abstract

Background
Matrix metalloproteinases (MMPs) have been reported to play an important role in tumour cell invasion and metastasis. The bioactivity of MMPs in liver metastasis from colorectal cancer was investigated and correlated with clinicopathological variables.

Method
Thirty-two patients underwent resection of colorectal cancer liver metastases. Latent and active forms of MMP were measured in tissue extracts, by means of quantitative gelatin zymography and a fluorometric activity assay.

Results
Broad-spectrum MMP activity, and levels of both active and latent forms of MMP-2 and MMP-9, were higher in tissues containing metastatic tumour than in normal liver tissue. Median metastatic to normal tissue ratios were 15·0 and 17·6 for active and proMMP-2 respectively, and those for active and proMMP-9 were 6·2 and 2·9. The ratios of active to latent enzyme were higher in metastatic tissue than in normal tissue. Lowered MMP-2 activity was associated with large metastatic lesions and increased proMMP-9 levels with preoperative chemotherapy. Both MMP-2 and MMP-9 activity were linked unfavourably to early recurrent disease.

Conclusion
These data suggest a role for MMPs in colorectal cancer liver metastasis, but indicate different roles for individual MMPs.
Lateral pelvic lymph node dissection for advanced lower rectal cancer
Authors: Fujita S , Yamamoto S , Akasu T , Moriya Y 
Published: November 2003

Abstract

Background
The oncological outcome of patients who underwent curative surgery for lower rectal cancer was investigated to clarify whether lateral pelvic lymph node dissection (LPLD) conferred any benefit.

Methods
A total of 246 patients who underwent curative surgery for stage II and III lower rectal cancer (below the peritoneal reflection) between 1985 and 1998 was reviewed. Forty-two of these patients did not undergo LPLD.

Results
Patients who did not undergo LPLD were older, more likely to have anterior resection and pelvic nerve preservation, and had smaller tumours and lymph node metastasis at an earlier stage than those who underwent LPLD. There was no difference in survival among patients with stage II and III disease between the two groups. However, in patients with pathological N1 lymph node metastasis, the 5-year disease-free survival rate was 73·3 per cent in patients who had LPLD compared with 35·3 per cent among those who did not (P = 0·013). Multivariate analysis showed that LPLD was a significant prognostic factor.

Conclusion
LPLD improved the prognosis of patients with stage III disease and a small number of lymph node metastases. A randomized clinical trial is needed to verify the benefit of LPLD.
Comparison of histological features and inflammatory cell reaction in alcoholic, idiopathic and tropical chronic pancreatitis
Authors: Shrikhande S V , Martignoni M E , Shrikhande M , Kappeler A , Ramesh H , Zimmermann A , Büchler M W , Friess H 
Published: November 2003

AbstractBackgroundThere is increasing evidence that immune mechanisms may be crucial in the development of alcoholic chronic pancreatitis. However, it is not known whether differences in underlying aetiology influence the inflammatory reaction in patients with chronic pancreatitis. The histological features and the pattern of inflammatory cell infiltration were studied in three aetiological forms of chronic pancreatitis: alcoholic, idiopathic and tropical pancreatitis.MethodsForty-three patients, ten with alcoholic, 12 with idiopathic and 21 with tropical chronic pancreatitis, were evaluated for the pattern of pancreatic inflammatory cell infiltration and histological features. Ten organ donors served as controls. Haematoxylin and eosin-stained tissue sections were used for histological evaluation. For immunohistochemical characterization of the inflammatory reaction, four antibodies—CD4, CD8, CD45 and CD68—were used. Quantitative evaluation of the various cell infiltrates was performed with computer-assisted image analysis. The inflammatory cell infiltration pattern was also evaluated.ResultsThe degree of endophlebitis and the overall density of plasma cells were greater in tropical than in alcoholic chronic pancreatitis. The grade of intralobular fibrosis was significantly higher in tropical chronic pancreatitis compared with the idiopathic form. No significant quantitative differences in the specific cellular infiltrates (CD4, CD8, CD45, CD68) were observed in the three different groups. However, the perivascular inflammation number score was significantly higher in alcoholic compared with idiopathic pancreatitis (P = 0·037), and the perivascular inflammation area score was significantly lower in idiopathic than in alcoholic (P = 0·024) or tropical (P = 0·020) pancreatitis.ConclusionDifferent aetiological forms of chronic pancreatitis result in similar histological features and a comparable inflammatory cell reaction, indicating that the disease, independent of the underlying aetiology, reaches a common immunological stage beyond which it appears to progress as a single distinctive entity.