bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of normal and expanded CAG repeat sizes influences age at onset of Huntington disease
Authors: Djoussé L. , Knowlton B. , Hayden M. , Almqvist E.W. , Brinkman R. , Ross C. , Margolis R. , Rosenblatt A. , Durr A. , Dode C. , Morrison P.J. , Novelletto A. , Frontali M. , Trent R.J.A. , McCusker E. , Gómez‐Tortosa E. , Mayo D. , Jones R. , Zanko A. , Nance M. , Abramson R. , Suchowersky O. , Paulsen J. , Harrison M. , Yang Q. , Cupples L.A. , Gusella J.F. , MacDonald M.E. , Myers R.H.
Published: May 2003

Huntington disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of CAG repeats in the HD gene on chromosome 4p16.3. Past studies have shown that the size of expanded CAG repeat is inversely associated with age at onset (AO) of HD. It is not known whether the normal Huntington allele size influences the relation between the expanded repeat and AO of HD. Data collected from two independent cohorts were used to test the hypothesis that the unexpanded CAG repeat interacts with the expanded CAG repeat to influence AO of HD. In the New England Huntington Disease Center Without Walls (NEHD) cohort of 221 HD affected persons and in the HD‐MAPS cohort of 533 HD affected persons, we found evidence supporting an interaction between the expanded and unexpanded CAG repeat sizes which influences AO of HD (P = 0.08 and 0.07, respectively). The association was statistically significant when both cohorts were combined (P = 0.012). The estimated heritability of the AO residual was 0.56 after adjustment for normal and expanded repeats and their interaction. An analysis of tertiles of repeats sizes revealed that the effect of the normal allele is seen among persons with large HD repeat sizes (47–83). These findings suggest that an increase in the size of the normal repeat may mitigate the expression of the disease among HD affected persons with large expanded CAG repeats. © 2003 Wiley‐Liss, Inc.
Gastroesophageal reflux and Cornelia de Lange syndrome: Typical and atypical symptoms
Authors: Luzzani S. , Macchini F. , Valadè A. , Milani D. , Selicorni A.
Published: May 2003

As previously reported, gastroesophageal reflux (GER) is a frequent and severe medical complication of Cornelia de Lange syndrome (CDLS). The incidence of GER and the correlation between its presence and degree, and the clinical phenotype of CDLS (mild/classical according to Van Allen classification) were evaluated in a series of 43 patients. The pattern of presenting symptoms and their clinical evolution after medical or surgical treatment were also studied. A pathological GER was evident in 28/43 (65%) CDLS patients. The incidence of the complication was not significantly different in patients with classical (93.3%) vs. mild phenotype (82.3%), whereas a strong correlation was present between the degree of the esophageal damage and the clinical phenotype. A behavioral symptom (hyperactivity) was the most frequent sign associated with the condition (85%). Our data confirm the high occurrence of GER in CDLS patients, independently from the CDLS clinical phenotype. Regarding the severity of the esophageal lesions, a significant difference between the two clinical CDLS phenotypes was found. The evaluation of the presenting symptoms and of their evolution during the treatment emphasizes the importance of behavioral symptoms as major signs of esophageal damage in CDLS. © 2003 Wiley‐Liss, Inc.
New variant of acro‐renal field defect
Authors: Scheuerman Oded , Horev Gadi , Merlob Paul
Published: May 2003

We describe two patients with a new variant of acro‐renal field defect. The first was a full‐term, small‐for‐gestational‐age female infant who showed preaxial polydactyly of the right hand and horseshoe kidney on abdominal ultrasonographic examination. In addition, there was a single umbilical artery and some mild facial errors of morphogenesis. The second patient, a full‐term male infant, had horseshoe kidney and left hand ectrodactyly. Various renal abnormalities have been described in the literature, but there are no reports on horseshoe kidney as part of acro‐renal field defect. We suggest that acro‐renal field defect should not be regarded as a definitive diagnosis, but only as a starting point for the search for various conditions. © 2003 Wiley‐Liss, Inc.
Interaction of genetic counselors with molecular genetic testing laboratories: Implications for non‐geneticist health care providers
Authors: McGovern Margaret M. , Benach Marta , Zinberg Randi
Published: May 2003

The availability of molecular genetic tests for the identification of mutant gene carriers, and for assessing individual genetic response to pharmacologic agents, infectious agents, and other environmental exposures, is expected to result in the increased use of the molecular genetic testing laboratory by primary care physicians. However, a number of concerns have been raised about such testing including the need for safeguards to protect patient privacy, and if the interface between genetic testing laboratories and the ordering physician facilitates the appropriate clinical use of the test result. In this study, genetic counselors were surveyed to determine their practices with regard to the clinical issues of informed consent and confidentiality in the context of genetic testing, and to assess their level of satisfaction with the reporting practices of molecular genetic testing laboratories. The results of this survey revealed that there is variability in the practices of genetic counselors with regard to obtaining informed consent, and that there are areas for improvement with regard to molecular genetic test reports, particularly in terms of interpretation of results. © 2003 Wiley‐Liss, Inc.
Deletion of the SHOX gene in patients with short stature of unknown cause
Authors: Morizio E. , Stuppia L. , Gatta V. , Fantasia D. , Guanciali Franchi P. , Rinaldi MM , Scarano G. , Concolino D. , Giannotti A. , Verrotti A. , Chiarelli F. , Calabrese G. , Palka G.
Published: May 2003

A fluorescence in situ hybridization (FISH) study was performed in 56 patients with short stature of unknown cause in order to establish the role of deletion of the SHOX gene in this population. FISH analysis was carried out on metaphase spreads and interphase lymphocytes from blood smears using a probe specific for the SHOX gene. Deletion of SHOX was found in four patients (7.1%). No skeletal abnormalities were detected in these patients either at the physical examination or at X‐rays of the upper and lower limbs. Present results indicate that SHOX plays an important role also in short stature of unknown cause, and FISH analysis appears as an easy, appropriate, and inexpensive method for the detection of SHOX deletion. © 2003 Wiley‐Liss, Inc.
Understanding why negative genetic test results sometimes fail to reassure
Authors: Michie Susan , Smith Jonathan A. , Senior Victoria , Marteau Theresa M.
Published: May 2003

A proportion of those receiving negative results following predictive genetic testing desire future bowel screening. This is despite a negative result meaning a general population risk of 1:7,500 and despite bowel screening being experienced as aversive and clinically unnecessary. This study aimed to investigate perceptions of risk, illness, and tests amongst those receiving negative results following predictive genetic testing. Interviews with nine people receiving negative genetic test results for familial adenomatous polyposis (FAP) were analyzed using the qualitative method, interpretative phenomenological analysis (IPA). Those not reassured by negative genetic test results perceived a continuing risk to themselves and to their children. Two sets of perceptions emerged that might explain this: (1) perceptions of the genetic basis of the condition (FAP). Although the condition was perceived to be genetic, genetic status was seen as transient, so a result today could not predict the future. The condition was also seen as caused by factors other than genes, so information about only one risk factor could not be reassuring. (2) Perceptions of the genetic test. There was a lack of conviction in the ability of the genetic test, based on a blood sample, to predict a disease located in the bowel. These results suggest that some individuals receiving negative test results are not reassured because of their representations of the cause of their condition and the nature of the tests they undergo. It may be that eliciting and, when appropriate, changing people's representations prior to testing may enable those receiving negative results to be more reassured about their residual risk. © 2003 Wiley‐Liss, Inc.
Application of a protocol for the detection of disorders of sialic acid metabolism to 124 high‐risk Brazilian patients
Authors: Castilhos Cristina D. , Mello Alexandre S. , Burin Maira G. , Guidobono Régis R. , Gotardo Silvane , Giugliani Roberto , Coelho Janice C.
Published: May 2003

Lysosomal storage disorders (LSD) present great clinical variability. Included in this group are sialic acid metabolism disorders (SAMD). In the present study, we describe the application of a 3‐step protocol for the diagnosis of SAMD, including (1) oligosaccharide and sialyloligosaccharide chromatography; (2) quantitative determination of sialic acid; and (3) measurement of neuraminidase activity. Application of our protocol to 124 individuals at risk for SAMD led to the diagnosis of five affected patients, two with type I sialidosis, one with type II sialidosis, and two with galactosialidosis. Due to its simplicity and efficiency, we propose the use of this protocol for the diagnostic evaluation of patients with suspected SAMD, which could be specially useful to non‐specialized laboratories and to services located in developing countries. © 2003 Wiley‐Liss, Inc.
Occlusal relief changes with molar wear in Pan troglodytes troglodytes and Gorilla gorilla gorilla
Authors: M'kirera Francis , Ungar Peter S.
Published: May 2003

Most research on primate tooth form–function relationships has focused on unworn teeth. This study presents a morphological comparison of variably worn lower second molars (M2s) of lowland gorillas (Gorilla gorilla gorilla; n=47) and common chimpanzees (Pan troglodytes troglodytes; n=54) using dental topographic analysis. High‐resolution replicas of occlusal surfaces were prepared and scanned in 3D by laser scanning. The resulting elevation data were used to create a geographic information system (GIS) for each tooth. Occlusal relief, defined as the ratio of 3D surface area to 2D planometric area of the occlusal table, was calculated and compared between wear stages, taxa, and sexes. The results failed to show a difference in occlusal relief between males and females of a given taxon, but did evince differences between wear stages and between taxa. A lack of significant interaction between wear stage and taxon factors suggests that differences in occlusal relief between chimpanzees and gorillas are maintained throughout the wear sequence. These results add to a growing body of information on how molar teeth change with wear, and how differences between primate species are maintained at comparable points throughout the wear sequence. Such studies provide new insights into form–function relationships, which will allow us to infer certain aspects of diet in fossils with worn teeth. Am. J. Primatol. 60:31–41, 2003.
Resting energy metabolism of Goeldi's monkey (Callimico goeldii) is similar to that of Other callitrichids
Authors: Power Michael L. , Tardif Suzette D. , Power Rachel A. , Layne Donna G.
Published: May 2003

The resting metabolic rates (RMRs) of six adult Goeldi's monkeys (Callimico goeldii) were measured using standard methods of open circuit respirometry during both the active (daytime) and inactive (nighttime) circadian phases for this species. One subject was measured both while she was pregnant and after she delivered a full‐term, stillborn infant. Inactive‐phase RMR within thermal neutrality (above 27.5°C) averaged 288.5±30.8 ml O2/hr; active‐phase RMR within thermal neutrality averaged 416.3±60.9 ml O2/hr. These values are 74.6% and 107.6%, respectively, of the mammalian expected for animals of this body mass. During the inactive phase, metabolic rate increased an estimated 4.3% for every degree decline in temperature below 27.5°C. The RMR in Goeldi's monkey is similar quantitatively and qualitatively to those of other captive callitrichids that have been studied, with active‐phase RMR being at or slightly above the mammalian expected, and inactive‐phase RMR being significantly reduced. We propose that this circadian pattern of RMR is a consequence of small body size, and is not a specific metabolic adaptation within the Callitrichidae. Thus we predict that metabolic studies measuring both circadian phases in other small primates will also find this pattern of reduced RMR during the inactive phase. The inactive‐phase RMR within thermal neutrality of the pregnant female was not different from that measured after the stillbirth, despite an almost 15% difference in body mass. During pregnancy, however, the female was more metabolically responsive to temperature below thermal neutrality, and had a lower upper critical temperature (i.e., was less tolerant of heat). Am. J. Primatol. 60:57–67, 2003. © 2003 Wiley‐Liss, Inc.
New method to census primate groups: Estimating group density of Japanese macaques by point census
Authors: Hanya Goro , Yoshihiro Shinichi , Zamma Koichiro , Kubo Ritsuko , Takahata Yukio
Published: May 2003

We devised a new method to estimate the density of primate groups in habitats that preclude the use of a line‐transect census because the ground is too steep. We combined point census and group follows. From the number of groups counted at a fixed point for an hour, n, group density D was calculated: $D = {{\lambda n} \over \pi}$. λ, the detectability constant, was a constant when distance‐dependent detectability g(y) was regressed on a half‐normal model: g(y) = e‐λ2 and can be estimated by combining the information of group follow and point census. Using this method, we estimated the group density of Japanese macaques in Yakushima. A census area of 7 km2 was divided into 28 grid squares (500 m×500 m). One observer was positioned at a point in each grid square, and those points were censused simultaneously for 4–6 days from 0600–0700 to 1500–1600 hr. Four troops were followed for 144 hr during the point census. Distance‐dependent detectability closely correlated with the half‐normal model. The detectability constant varied with the time of day, but it was not influenced by troop identity or topography. Group density was calculated to be 1.48±0.61 and 0.701±0.432 groups/km2 in the disturbed and undisturbed areas, respectively (95% confidence limit). “True” group density estimated by home range data was within the confidence limit calculated by a point census in the home range of the troops for two troops, suggesting that this method was valid. This method is applicable to other species as long as at least one group can be followed, because it satisfies the fundamental assumptions of point census, and the detectability does not seem to be biased by troop or topography. Am. J. Primatol. 60:43–56, 2003.
Preparation and characterization of amphiphilic block copolymer of polyacrylonitrile‐block‐poly(ethylene oxide)
Authors: Sui Kunyan , Gu Lixia
Published: May 2003

The synthesis of polyacrylonitrile‐block‐poly(ethylene oxide) (PAN‐b‐PEO) diblock copolymers is conducted by sequential initiation and Ce(IV) redox polymerization using amino‐alcohol as the parent compound. In the first step, amino‐alcohol potassium with a protected amine group initiates the polymerization of ethylene oxide (EO) to yield poly(ethylene oxide) (PEO) with an amine end group (PEO‐NH2), which is used to synthesize a PAN‐b‐PEO diblock copolymer with Ce(IV) that takes place in the redox initiation system. A PAN‐poly(ethylene glycol)‐PAN (PAN‐PEG‐PAN) triblock copolymer is prepared by the same redox system consisting of ceric ions and PEG in an aqueous medium. The structure of the copolymer is characterized in detail by GPC, IR, 1H‐NMR, DSC, and X‐ray diffraction. The propagation of the PAN chain is dependent on the molecular weight and concentration of the PEO prepolymer. The crystallization of the PAN and PEO block is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1753–1759, 2003
The scaling analysis of thermooxidative degradation of poly(arylatearylene sulfonoxide)
Authors: Kozlov G. V. , Batyrova H. M. , Zaikov G. E.
Published: May 2003

It is shown that scaling relationships adequately describe the process of oxygen consumption in the course of thermooxidative degradation of poly(arylatearylene sulfonoxide). The correspondence of the experimental curve amount of the consumed oxygen time to one or another scaling relationship allows the definition of the mechanism of thermooxidative degradation. So, for poly(arylatearylene sulfonoxide), the mode of autodeceleration corresponds to the attack by oxygen molecules of the polymeric macromolecules reactive centers, and the mode of autoacceleration corresponds to the reaction of low molecular radicals. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1760–1763, 2003
The structural treatment of a number of effective centers of polymeric chains in the process of the thermooxidative degradation
Authors: Kozlov G. V. , Batyrova H. M. , Zaikov G. E.
Published: May 2003

It is shown that the effective number of the polymeric macromolecule reactive centers depends on the macromolecular coil structure. The quantitative characteristic of the latter one can be received within the framework of the fractal analysis. The increase in macromolecular coil fractal dimension, meaning the rise of a degree of its compactness, results in lowering the effective number of the reactive (accessible to the molecules of oxidant) sites of a polymeric macromolecule. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1764–1767, 2003
Influence of recycling and contamination on structure and transport properties of polypropylene
Authors: Incarnato Loredana , Scarfato Paola , Acierno Domenico , Milana Maria Rosaria , Feliciani Roberta
Published: May 2003

In this work the effect of three processing cycles on the physical properties of polypropylene (PP) was studied and related to the changes in the structure (molecular weight, molecular weight distribution, morphology) occurring during recycling. In order to simulate both the use and the recycling process of PP in the laboratory, PP pellets were contaminated with three model substances and submitted to three cycles of processing by injection molding. The bars for testing were produced from virgin and recycled polymers. The amount of degradation occurring during the reprocessing was estimated by means of viscosity and gel permeation chromatography measurements. Differential scanning calorimetry and scanning electron microscopy analyses were performed to investigate the crystallization behavior and the morphology of virgin and recycled PP. In order to obtain information on the structural organization and mobility of the amorphous phase, a dynamic mechanical thermal analysis and measurements of the transport properties were carried out. The results obtained were attributed to the different structural organization of the bars in relation to the number of processing cycles and contamination. Part of the work was focused on the recyclability of PP for food packaging applications, considering the residual contamination and migrational behavior after repeated processing cycles. In particular, the relationships existing between reprocessing, the residual amounts of contaminants, and the migrational behavior were investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1768–1778, 2003
Investigation of microstructure of the acrylonitrile‐styrene‐glycidyl methacrylate terpolymers by 1D and 2D NMR spectroscopy
Authors: A. S. Brar  , Pradhan D. R.
Published: May 2003

Acrylonitrile‐styrene‐glycidyl methacrylate (N/S/G) terpolymers were prepared by bulk polymerization by using benzoyl peroxide as initiator and analyzed by NMR spectroscopy. The compositions of terpolymers were determined by quantitative 13C{1H}‐NMR spectra and compared with those calculated by Goldfinger's equation by using comonomer reactivity ratios: rNS = 0.04, rSN = 0.40; rNG = 0.22, rGN = 1.37; rSG = 0.44, rGS = 0.53. The 13C{1H}‐ and 1H‐NMR spectra were overlapping and complex. The spectral assignments were done with the help of distortionless enhancement by polarization transfer and two‐dimensional 13C‐1H heteronuclear single quantum correlation experiments. 2D total correlated spectroscopy was used to ascertain the various coupling between the protons. The methyl, methine, methylene, and oxymethylene carbon resonances showed compositional sensitivity. 2D nuclear Overhauser enhancement spectroscopy (NOESY) experiment was used to ascertain the spatial proton–proton couplings. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1779–1790, 2003
Determination of optical properties, dispersion, and structural parameters of poly(ethylene terephthalate) fibers using automatic variable wavelength interferometry technique
Authors: Sokkar T. Z. N. , El‐Farahary K. A. , El‐Bakary M. A.
Published: May 2003

Automatic variable wavelength interferometry (VAWI) is used in combination with a Pluta double refracting polarizing interference microscope for measuring the spectral dispersion parameters of the refractive indices of poly(ethylene terephthalate) (PET) highly oriented yarn fibers (1000 denier/250 filaments). The resulting data are utilized to calculate the spectral dispersion and structural parameters such as Cauchy's constants, the dispersion energy, the oscillation energy, the density, the mean polarizability of the monomer unit, the number of monomer units per unit volume, the dielectric constant, the electric susceptibility, the optical orientation function, and the electric polarizability constant. Microinterferograms are given for illustration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1737–1742, 2003
Study of poly(ethylene terephthalate)/polypropylene microfibrillar composites. I. Morphological development in melt extrusion
Authors: Lin X. D. , Cheung W. L.
Published: May 2003

Poly(ethylene terephthalate)/polypropylene (PET/PP) blends of different compositions were extruded through a 2‐mm capillary die using a corotating twin‐screw extruder. The extrudates were cryogenically fractured and examined using scanning electron microscopy. The viscosity ratio of the constituent polymers alone was found to be unsuitable for explaining the polymer blend morphology. At a PET concentration of 20%, the extrudate consists of three regions. The skin layer, which is about 10 μm thick, has a lower concentration of the dispersed PET phase than the overall concentration. The intermediate region, which is about 400 μm thick, has profuse PET fibers and some small PET particles. The central region, which is approximately 800 μm in diameter, mainly contains PET particles that are generally bigger. A low barrel temperature, low die temperature, and fast cooling rate helped to retain the fibers near the extrudate skin. Meanwhile, the variation of the barrel temperature, die temperature, and cooling media did not produce a significant affect on the PET particle size distribution in the central region of the extrudate. A high screw speed and a high postextrusion drawing speed were very effective in producing fibers in the extrudates through elongation of particles. At a PET concentration of 30%, coalescence of the PET phase was prevalent, leading to the formation of PET platelets near the extrudate skin and irregular PET networks in the central region of the extrudate. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1743–1752, 2003
Effect of the composition on the phase size in immiscible blends with the viscosity ratio close to unity
Authors: Zeng Jijun , Aoyama Masatoshi , Takahashi Hiroshi
Published: May 2003

The influence of the composition and interfacial tension on the phase size in immiscible polymer blends with a viscosity ratio close to unity has been investigated with poly(methyl methacrylate)/poly(ethylene terephthalate) blends and data from various works. For all the blends considered, the dispersed particle diameter (d) is proportional to the interfacial tension of the system. When the dispersed‐phase content (ϕ) is below 1%, there is minimal change of d with increasing ϕ. When ϕ is between 1 and 20%, d is proportional to ϕ0.4. It seems that the processing conditions do not influence the morphology significantly for blend systems with a viscosity ratio close to unity.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1791–1799, 2003
Synthesis of a high‐trans 1,4‐butadiene/isoprene copolymers with supported titanium catalysts
Authors: He Aihua , Huang Baochen , Jiao Shuke , Hu Youliang
Published: May 2003

The copolymerization of butadiene (Bd) and isoprene (Ip) with a supported titanium‐triisobutyl aluminum catalyst system was studied. An analysis using differential scanning calorimetry, X‐ray diffraction, and13C‐NMR spectra indicated that products with 25–60 mol % Bd units were random copolymers and that the melting temperatures and glass‐transition temperatures (Tg) were 30–40 and −74°C (or thereabout), respectively, which were very similar to those of natural rubber. The chemical structure of these copolymers was characterized by a high‐trans 1,4‐configuration: the trans 1,4‐content of Ip units was greater than 98%, and the trans 1,4‐content of Bd units was greater than 90%. The reactivity ratio of Bd was greater than that of Ip (rBd= 5.7 andrIp= 0.17). The sequence distribution of the monomer units of the copolymers followed a first‐order Markov statistical model. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1800–1807, 2003
Synthesis and kinetic analysis of 1,4‐naphthalene‐di(carboxylic acid) and hydroquinone diacetate based homopolyesters
Authors: Al‐Adwani H. , Bishara A. , Shaban H.
Published: May 2003

A variety of high temperature liquid crystalline polymers can be developed using the homopolyester of 1,4‐naphthalene di(carboxylic acid) (1,4‐NDCA) and hydroquinone diacetate (HQDA) as a spacer. In such cases the monomer 1,4 NDCA acts as a kink. Kinetic studies of the synthesis of homopolyesters by melt polymerization using 1,4‐NDCA and hydroquinone diacetate (HQDA) are reported. The performance of two transesterification catalysts are estimated for this system. In this study, initial stage polymerization kinetics of the homopolyesters were examined. The side product, acetic acid, evolved in the homopolymerization of 1,4‐NDCA and HQDA, was used to estimate the progress of the reaction. The polycondensations were found to obey second order kinetics, regardless of whether the reaction was catalyzed or uncatalyzed.

A set of twelve differential equations containing four different rate constants, k1, k2, k3 and k4 has been developed and computed, to study the initial stage kinetics. The computed values of acetic acid are compared with the experimentally collected amounts, and the four rate constants are optimized using a differential algebraic optimization technique. The present model represents the data with an acceptable accuracy and with an average percentage error of less than 5% for the entire experimental range. The correlation coefficient values range from 0.95 to 0.99 for all experimental data. The kinetic constants and activation energy values are reported.

Differential scanning calorimetric (DSC) analysis of the homopolyesters indicate that 1,4 NDCA–HQDA had the highest melting temperature, around 350°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1808–1817, 2003
Polyimide asymmetric membranes: Elaboration, morphology, and gas permeation performance
Authors: Leblanc N. , Le Cerf D. , Chappey C. , Langevin D. , Métayer M. , Muller G.
Published: May 2003

Asymmetric 2,2‐bis‐(3,4‐dicarboxyphenyl) hexafluoropropane dianhydride (6FDA)‐2‐methyl‐1,3‐phenylenediamine (mPDA) polyimide membranes were prepared according to a phase‐inversion mechanism by using different solvent/nonsolvent blends. The membrane formation mechanism and the final performances of the asymmetric membranes have been found both nonsolvent and solvent nature dependent. From the visualization of cross sections of asymmetric membranes by scanning electron microscopy and the study of the permeation of two gases (N2, CO2) through asymmetric membranes, a relationship between elaboration conditions and asymmetric membranes characteristics could be drawn. The organization of polymer chains in solution strongly affects the final polymer arrangement and thus the final performances of the membrane. The influence of preliminary solvent evaporation before immersion has been shown to be dependent on the structure of the asymmetric membrane: finger‐like or sponge‐like structures. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1838–1848, 2003
Gas transport properties of poly(ethylene‐2,6‐naphtalene dicarboxylate) films: Influence of crystallinity and orientation
Authors: Hardy L. , Espuche E. , Seytre G. , Stevenson I.
Published: May 2003

H2 and CO2 transport properties were investigated on semicrystalline poly(ethylene‐2,6‐dicarboxylate naphtalene) (PEN) films and biaxially stretched films and analyzed in terms of solubility and diffusion. The decrease of the permeability observed on the thermally crystallized samples has been described by Maxwell's law. No change of the sorption properties of the amorphous phase has been noticed as a function of the thermal treatment and the evolution of the diffusion coefficient has been related to a tortuosity effect. The low permeability measured on the biaxially stretched film is related to both a change of the free volume sizes distribution and a tortuosity effect. The interesting barrier properties of the biaxially stretched film are kept even after annealing the film at 250°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1849–1857, 2003
Pseudo‐interpenetrating polymer networks based on tetrafunctional epoxy resins and poly(methyl methacrylate)
Authors: Alcântara Robério Marcos , Pires Alfredo Tibúrcio Nunes , De Barros Glaucione Gomes , Belfiore Laurence A.
Published: May 2003

Pseudo‐interpenetrating polymer networks (p‐IPNs) of an epoxy resin and poly(methyl methacrylate) (PMMA) were synthesized simultaneously. Methyl methacrylate (MMA) was polymerized with benzoyl peroxide in the presence of an oligomeric epoxy resin, which contained stoichiometric amounts of either a tetrafunctional [i.e., ethylenediamine (EDA)] or hexafunctional [i.e., triethylenetetramine (TETA)] crosslinking agent. The resulting materials would be useful for aerospace, automotive, medical, and dental applications. The structure of the epoxy resin (i.e., tetraglycidyl 4,4′‐diamine diphenyl methane) was confirmed by elemental analysis and IR and NMR spectroscopies. The thermal, mechanical, and kinetic behaviors of the polymeric networks produced from this oligomeric epoxy resin and the p‐IPNs of this crosslinked epoxy with linear PMMA were compared. Time‐resolved IR spectroscopy of the cyclic ether group in the epoxy at 906 cm−1 revealed kinetic information between 40 and 80°C for a complex reaction scheme. In the absence of MMA, the asymptotic final conversion of epoxide groups was achieved after (1) 60 min of chemical crosslinking at 50°C and (2) 30 min of crosslinking at 80°C with tetrafunctional EDA. In the presence of 10 wt % MMA, asymptotic final conversions of the epoxide group were achieved after (1) 150 min at 40°C, (2) 80 min at 50°C, and (3) 30 min at 80°C. In agreement with other kinetic studies based on the same epoxy resin but different crosslinking agents, these solvent‐free polymerizations were diffusion‐controlled during the later stages of chemical crosslinking because the apparent reaction order was very close to unity, via an unsteady state batch reactor model with lumped‐parameter kinetics. The thermal expansion coefficients of the crosslinked epoxy resin increased at higher concentrations of PMMA, but hexafunctional TETA produced a higher crosslink density and reduced the thermal expansion relative to the same networks and p‐IPNs prepared with tetrafunctional EDA. Elastic modulus, fracture stress, and toughness increased synergistically when the epoxy resin was crosslinked with EDA at 40°C in the presence of 10 wt % MMA. This p‐IPN exhibited minimal shrinkage, on the order of 0.15%, during the actual polymerization. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1858–1868, 2003
Brominated phenol–formaldehyde resin as an adhesive for plywood
Authors: Petsom Amorn , Roengsumran Sophon , Hanphichanchai Supattra , Sangvanich Polkit
Published: May 2003

A brominated phenol–formaldehyde resin was investigated as a plywood adhesive to study the effect of bromine on the physical and flammability properties of this resin. The results of these studies showed that brominated phenol–formaldehyde resin of 10% bromine content by weight of the phenol–formaldehyde resin was suitable to be used as a plywood adhesive. The optimal compressing temperature and compressing time were 110°C and 30 min, respectively. The prepared plywood obtained from the optimal condition gave a high shear strength, good flame retardancy, and good resistance to both hot and cold water. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1918–1924, 2003
Poly(sulfobetaine)s and corresponding cationic polymers. IX. Synthesis and aqueous solution properties of zwitterionic poly(sulfobetaine) derived from a styrene–N,N‐dimethylaminopropyl maleamidic acid copolymer
Authors: Lee Wen‐Fu , Chen Yan‐Ming
Published: May 2003

A styrene–N,N‐dimethyl(maleamidic acid)propyl ammonium propane sulfonate (SDMMAAPS) copolymer was synthesized through an amidoacidation reaction of a styrene–maleic anhydride alternating copolymer with N,N‐dimethylaminopropylamine (ring‐opening reaction) and then reacted with propane sultone. The cloud point and minimum salt concentration (msc) of this ampholytic SDMMAAPS copolymer were determined in aqueous salt solutions. The effects of counterions on the cloud point and msc of SDMMAAPS were not entirely the same as those of other zwitterionic poly(sulfobetaine)s. The greatest difference from other poly(sulfobetaine)s, such as styrene–N,N‐dimethyl(maleimido propyl)ammonium propane sulfonate copolymers, was the carboxylic group on the polymer chain unit of SDMMAAPS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1884–1889, 2003
Synthesis of polyurethane/polyethylene grafted polymers using cyclotriphosphazene as a coupling agent
Authors: Dez Isabelle , De Jaeger Roger
Published: May 2003

The reaction between a dihydroxyphenoxycyclotriphosphazene containing allylic functions, 3, and hexamethylene‐1,6‐diisocyanate (HDI) leads to a new cyclotriphosphazene‐substituted polyurethane 4. The structures of both classes of compounds involved in that synthesis were investigated by 31P‐, 13C‐, and 1H‐NMR, infrared, and mass spectrometries, size‐exclusion chromatography, and elemental analysis. The thermal behavior of 4 was investigated and compared to that of hexaphenoxycyclotriphosphazene, N3P3(OC6H5)6, and of a polyurethane synthesized from 1,3‐bis(hydroxy)benzene and HDI. The free‐radical‐promoted grafting of 4 onto the polyethylene surface is described. The resultant surface was studied by ATR–IR, XPS, and contact‐angle techniques. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1925–1934, 2003
Synthesis and properties of the semi‐interpenetrating polymer network–like, thermosensitive poly(N‐isopropylacrylamide) hydrogel
Authors: Zhang Xian‐Zheng , Chu Chih‐Chang
Published: May 2003

A new strategy was used to prepare a semi‐interpenetrating polymer network (semi‐IPN)–like poly(N‐isopropylacrylamide) (PNIPAAm) polymeric hydrogel, consisting of either low (2300) or high (33,000) molecular weight linear PNIPAAm chains and the crosslinked PNIPAAm network. The properties of the resulting PNIPAAm hydrogels were characterized by DSC and SEM as well as their swelling ratios at various temperatures, the deswelling in hot water (48°C), and the oscillating shrinking–swelling properties within small temperature cycles. It was found that the deswelling rate of these semi‐IPN–like PNIPAAm hydrogels was improved if the molecular weight and/or composition of the linear PNIPAAm chains within the semi‐IPN–like PNIPAAm hydrogels were increased. This improved deswelling rate was attributed to the fast response nature of the linear PNIPAAm chains and the increased pore number in the matrix network, which provided numerous water channels for the water to diffuse out during the deswelling process at a temperature above the lower critical solution temperature. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1935–1941, 2003
Ce(IV)‐initiated graft polymerization of acrylic acid onto poly(ethylene terephthalate) fiber
Authors: Chansook N. , Kiatkamjornwong S.
Published: May 2003

Graft copolymerization of acrylic acid onto poly(ethylene terephthalate) (PET) fiber by a redox system using ceric (IV) initiator was studied with regard to various parameters of importance: acrylic acid concentration, ceric (IV) concentration, nitric acid concentration, reaction temperature, and reaction time. Based on the morphology of the PET fiber, it could be concluded that ceric (IV) in dilute nitric acid is a redox initiator for the surface graft copolymerization of the acrylic acid/PET system. The grafted PET fiber showed an increase in improved moisture regain to reach 900% at 39.5% graft yield. The dyeability with the basic dye and disperse dye significantly increased by 100 and 22%, respectively, as a result of the grafting onto PET fiber. Both tenacity and elongation gradually decreased by 51.2 and 28.9%, respectively, with increasing graft yield, which reduced the fiber service lifespan. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1952–1958, 2003
Cashew nut shell liquid–based tailor‐made novolac resins: Polymer morphology quantitation by 1‐D and 2‐D NMR techniques and performance evaluation
Authors: Roy Debmalya , Basu P. K. , Raghunathan P. , Eswaran S. V.
Published: May 2003

The application of cashew nut shell liquid (CNSL) and CNSL‐based polymers in the burgeoning microelectronics industry is rare. “High ortho” alternating and semialternating tailor‐made novolac copolymers based on CNSL and m‐cresol and/or p‐cresol and have been made and successfully used as photoresists for microlithography. The microstructure of one of the representative m‐cresol copolymer is exhaustively elucidated based on 1‐D and 2‐D NMR techniques. Incorporation of different monomers in the resin backbone has been quantitatively estimated based on an improved NMR methodology. The lithographic performance of photoresists using novolac resins based on cardanol (fractionated CNSL) and diazonaphthoquinone ester was also evaluated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1959–1965, 2003
Effect of the copolycondensation temperature on the reactivities of bis(3‐hydroxypropyl)terephthalate and bis(2‐hydroxyethyl)terephthalate
Authors: Sik Yoon Won , Seok Lyoo Won , Do Ghim Han , Lee Jinwon , Ho Kim Joon , Soo Kim Sam
Published: May 2003

The rate constants of cross reactions in the copolycondensation of bis(3‐hydroxypropyl)terephthalate (BHPT) and bis(2‐hydroxyethyl)terephthalate (BHET), k12 and k21, were determined with the results obtained from 1H NMR spectroscopy analysis. BHPT and BHET were polymerized and copolymerized at 260, 270, and 280°C with titanium tetrabutoxide as a catalyst. With the adoption of second‐order kinetics to the polycondensation, k11 and k22 were calculated. The monomer reactivity ratios of BHPT were much larger than those of BHET, indicating the block nature of the copolycondensation, but the difference between the reactivity ratios was lowest at the highest polycondensation temperature of 280°C. This indicated that the probability of randomization was increased. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1890–1895, 2003
Membrane properties of microporous structures prepared from polyethylene/polymethacrylate IPN
Authors: Pionteck Jürgen , Hu Jianjiang , Schulze Ulrich
Published: May 2003

Polyethylene/polymethacrylate interpenetrating polymer networks (PE/PMA IPN) form a matrix–particle or a co‐continuous morphology that can be adjusted by the composition and synthesis conditions. Based on the fact that PMA degrades whereas PE crosslinks when they are exposed to energetic irradiation, we developed a new approach to create a porous structure by electron beam irradiation. IPN systems that differ in the methacrylate components and composition were studied. One system contains poly(butyl methacrylate‐co‐methyl methacrylate) (BMA‐co‐MMA) and the other contains poly(dodecyl methacrylate‐co‐ethyl methacrylate) (DMA‐co‐EMA) as the PMA phase. After electron beam irradiation followed by extraction with xylene, both IPN systems have a porous structure that is permeable to water. However, the structure and size of the pores depend on the PMA components and the synthesis conditions. PMAs with long aliphatic side chains degrade less than PMAs containing only short aliphatic pendant groups. Therefore, the PE/BMA‐co‐MMA IPN forms bigger pores than PE/DMA‐co‐EMA, resulting in a higher water flux. The molecular cutoffs of the IPN are characteristic for microfiltration or ultrafiltration.© 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1976–1982, 2003
Preparation of high capacity weak base poly(methyl methacrylate)–ethylene glycol dimethylacrylate copolymer anion exchange resin by modification using NOx
Authors: Sinha Shishir , Jayaswal Namita , Kumar Anil
Published: May 2003

Macroporous poly(methyl methacrylate)–ethylene glycol dimethylacrylate (PMMA–EGDM) resin (resin 1) was prepared by suspension polymerization and gelatin was found to be the key component deciding the size of particles. To prepare aminated macroporous weak base PMMA–EGDM exchanger, resin 1 was nitrated using NO2 gas with a minor amount of NO (termed NOx). The modified PMMA–EGDM resin (resin 2) was reduced to NH2 groups and the exchange capacity of the weak base anion exchange resin (resin 3) was determined. Regression analysis of NOx consumption versus time and the exchange capacity Q versus time data suggested a second‐order kinetics for the modification reaction and these are reported. We examined the effect of duration of nitration on the exchange capacity of resin 3. It was found that it first increased with the increase in the extent of nitration, reaching a broad maximum of 4.8 meq/g of wet resin with 78% moisture for about 8 h of nitration, and decreasing for longer nitration times as a result of polymer degradation. These results were compared with commercial resin, which had an exchange capacity of 1.68 meq/wet g with 43% moisture content. To assess the salvation ability of the modified PMMA–EGDM resin, consistent with the literature, we devised three stages of removing moisture. Experiments suggest that the high capacity of the modified PMMA–EGDM resin may be attributed to this increased salvation ability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1991–1999, 2003
Cloud‐point measurements for salt + poly(ethylene glycol) + water systems by viscometry and laser beam scattering methods
Authors: Nozary S. , Modarress H. , Eliassi A.
Published: May 2003

The phase separation of salt + poly(ethylene glycol) + water systems was studied by cloud‐point measurements using viscometry and laser beam scattering methods. The Flory–Huggins model was applied to determinate the condition for salt‐induced liquid–liquid phase separation in the system. A temperature‐ and concentration‐dependent interaction parameter was employed to fit the phase diagrams for the systems. The temperature and concentration functionality of the interaction parameter was determined and used to predict cloud‐point curves for the systems. The cloud‐point curves were found to be in quantitative agreement with experimental data. Also, the effect of various salts on the measured cloud points was studied. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1983–1990, 2003
Effect of nitrogen and oxygen incorporated into TMSAA plasma coating on surface‐bound heparin activity
Authors: Chen Meng , Osaki Shigemasa (Gem) , Zamora Paul O. , Potekhin Mila
Published: May 2003

To investigate the influence of nitrogen and oxygen incorporated into N‐trimethylsilylallyamine (TMSAA) plasma coating on heparin binding to the surfaces, four types of monomer combinations were utilized. Those combinations include TMSAA alone, TMSAA mixed with nitrogen (TMSAA + N2), with air (TMSAA + air), and with oxygen (TMSAA + O2). Fourier transform infrared (FTIR) spectroscopy was employed to study the coating of the bulk structure. The thickness and surface morphology of the coatings were measured using atomic force microscopy (AFM). Electron spectroscopy for chemical analysis (ESCA) and the contact angle were used to investigate the surface elemental composition and hydrophilicity, respectively. It was found that the incorporation of oxygen into the coating formation significantly increased the deposition rate of the TMSAA + O2 coating, but the heparin activity was the least even though it made the coating surface more hydrophilic. This is considered to have resulted from the loss of nitrogen in the coating structure due to the oxygen replacement to nitrogen. The nitrogen incorporated into the coating had no noticeable effect on the heparin surface‐binding ability. The TMSAA + air plasma grafting process exhibited the best heparin attachment to the surface, which could be largely attributed to its highest surface roughness, although the nitrogen composition was decreased to some extent compared to the pure TMSAA plasma coating. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1875–1883, 2003
Pharmacokinetics and bioequivalence evaluation of two simvastatin 40 mg tablets (Simvast & Zocor) in healthy human volunteers
Authors: Najib Naji M. , Idkaidek Nasir , Adel Ayman , Admour Isra' , Astigarraga Rafel E. B. , Nucci Gliberto De , Alam S. Mahmood , Dham Ruwayda , Qumaruzaman
Published: May 2003

The pharmacokinetics of two brands of simvastatin 40 mg tablets were compared in 24 healthy human volunteers after a single oral dose in a randomized cross‐over study, conducted at IPRC, Amman, Jordan. Reference (Zocor, MSD, Netherlands) and test (Simvast, Julphar, UAE) products were administered to fasted volunteers; blood samples were collected at specified time intervals, plasma separated and analyzed for simvastatin and its active metabolite (β‐hydoxy acid) using a validated LC–MS/MS method at Cartesius Analytical Unit, Institute of Biomedical Sciences – USP, Sao Paulo, Brazil. The pharmacokinetic parameters AUC0−t, AUC0−∝, CMAX, TMAX, T1/2 and elimination rate constant were determined from plasma concentration–time profile for both formulations and were compared statistically to evaluate bioequivalence between the two brands, using the statistical modules recommended by FDA. The analysis of variance (ANOVA) did not show any significant difference between the two formulations and 90% confidence intervals fell within the acceptable range for bioequivalence. Based on these statistical inferences it was concluded that the two brands exhibited comparable pharmacokinetic profiles and that Julphar's Simvast is bioequivalent to Zocor of MSD, Netherlands. Copyright © 2003 John Wiley & Sons, Ltd.