bluuebunny/crossref_metadata_2025 huggingface dataset:
Additional patient with del(12)(q21.2q22): Further evidence for a candidate region for cardio‐facio‐cutaneous syndrome?
Authors: Rauen Katherine A. , Albertson Donna G. , Pinkel Daniel , Cotter Philip D.
Published: August 2002

Cardio‐facio‐cutaneous (CFC) syndrome is characterized by a distinct facial appearance, cardiac defects, ectodermal anomalies and developmental delay. Recently, we reported a 19‐month‐old girl with phenotypic manifestations consistent with the CFC syndrome who had an interstitial deletion of the long arm of chromosome 12, del(12)(q21.2q22), implicating a possible locus for CFC syndrome. Here, we report an additional patient with a cytogenetically identical interstitial deletion: 47,XYY,del(12)(q21.2q22). To further characterize this deletion we used microarray‐based comparative genomic hybridization (array CGH). Array CGH confirmed both the deletion and the second Y chromosome. The deletion on chromosome 12q spanned at least 14 Mb as indicated by the positions on the genome sequence of the 4 BAC clones included in the deletion. While the proband did not have the classic features of CFC, he had some dysmorphic craniofacial characteristics, ectodermal anomalies and moderate developmental delay which were suggestive of CFC syndrome; however, this patient did not have classical CFC. The phenotypic differences between the two del(12)(q21.2q22) patients may be due to variability in the expression of the syndrome, or this deletion may present as a syndrome with overlapping features. Alternatively, the phenotypic differences may result from discordance at the molecular level, which may yield a critical minimal region of deletion for CFC. The region 12q21.2 → q22 remains a possible candidate region for CFC syndrome. Additional characterization of these and other CFC patients may confirm and further refine this candidate region. © 2002 Wiley‐Liss, Inc.
Meiosis and chromosome painting of sex chromosome systems in Ceboidea
Authors: Mudry M.D. , Rahn I.M. , Solari A.J.
Published: August 2002

The identity of the chromosomes involved in the multiple sex system ofAlouatta caraya(Aca) and the possible distribution of this system among other Ceboidea were investigated by chromosome painting of mitotic cells from five species and by analysis of meiosis at pachytene in two species. The identity of the autosome #7 (X2) involved in the multiple system ofAcaand its breakage points were demonstrated by both meiosis and chromosome painting. These features are identical to those described by Consigliere et al. [1996] inAlouatta seniculus sara(Assa) andAlouatta seniculus arctoidea(Asar). This multiple system was absent in the other four Ceboidea species studied here. However, data from the literature strongly suggest the presence of this multiple in other members of this genus. The presence of this multiple system among several species and subspecies that show high levels of chromosome rearrangements may suggest a special selective value of this multiple. The meiotic features of the sex systems ofAcaandCebus apella paraguayanus(Cap) are strikingly different at pachytene, as the latter system is similar to the sex pair of man and other primates. The relatively large genetic distances between species presently showing this multiple system suggest that its origin is not recent. Other members of the same genus should be investigated at meiosis and by chromosome painting in order to know the extent and distribution of this complex sex‐chromosome system. Am. J. Primatol. 54:65–78, 2001. © 2001 Wiley‐Liss, Inc.
Sources of variability in numbers of live births in wild golden lion tamarins (Leontopithecus rosalia)
Authors: Bales Karen , O’Herron Michelle , Baker Andrew J. , Dietz James M.
Published: August 2002

We examined the effects of several variables on the number of live births in multiparous females in a wild population of golden lion tamarins (Leontopithecus rosalia). Independent variables included the number of infants born to a female the previous breeding season, the number of infants weaned the previous breeding season, the female’s age and body mass, the number of adult males and helpers in the group, and the inbreeding coefficient of the offspring. We also tested the hypothesis that trapping and chemical immobilization during pregnancy affected the number of live births. Female body mass was the only statistically significant predictor of the number of live‐born infants in the current season when both first and second peaks were included. Characteristics that predicted higher numbers of infants in the first peak of a season were the number of infants born the previous season and the body mass of the female. The greater the number of infants born the previous season, the greater the number of infants born in the first peak of the current season. Factors positively correlated with the number of live births in the second peak within a season included the number of infants born the previous season, as well as the number of available helpers. Due to sample size constraints, the analysis of litters in the second peak did not include body mass of the female as a variable. Inbreeding and handling did not affect the number of live births. We found no evidence that current reproduction negatively impacts future reproduction in this species. We also found no evidence for an age‐related reduction in fertility. Am. J. Primatol. 54:211–221, 2001. © 2001 Wiley‐Liss, Inc.
Identifying metameric variation in extant hominoid and fossil hominid mandibular molars
Authors: Hlusko Leslea J.
Published: August 2002

Landmark data were collected from cross sections and occlusal images of mandibular molar crowns, and Euclidean distance matrix analysis (EDMA) was used to identify metameric morphological variation between the first and second mandibular molars of living taxa: Gorilla gorilla (n = 30), Pan troglodytes (n = 34), and Homo sapiens (n = 26). Two patterns of metameric variation were identified, one unique to humans and the other shared by chimpanzees and gorillas.

In order to assess the utility of this type of analysis for the interpretation of the hominid fossil record, 19 mandibular molars from Sterkfontein Member 4, South Africa, were examined. The pattern of metameric variation of the Sterkfontein molars resembled that of the African great apes, and differed from the modern human pattern. These results demonstrate that data on metameric variation may provide information regarding function or developmental processes previously indiscernible from fossil material. Am J Phys Anthropol 118:86–97, 2002. © 2002 Wiley‐Liss, Inc.
Waiting for Trivers and Willard: Do the rich really favor sons?
Authors: Koziel Slawomir , Ulijaszek Stanley J.
Published: August 2002

Parental investment theory has been put forward as a major evolutionary argument explaining male or female biased birth sex ratio, the Trivers‐Willard (T‐W) hypothesis, predicting that parents living in good circumstances will bias their investment to sons, whereas parents in poor circumstances will bias their investment toward daughters. Tests of the T‐W hypothesis on human beings have shown limited evidence for parents appearing to differentiate their investment to sons or daughters according to the reproductive potential of each sex. The present study tests the T‐W hypothesis among a large contemporary Polish sample using first birth interval and extent of breastfeeding as measures of parental investment, and economic status and level of parental education as measures of parental condition. The extents to which parental investment and markers of parental condition vary by sex of the child were examined using log‐linear analysis. Weak support for the T‐W effect is found among families where fathers were best educated, where a greater proportion of first‐born boys are breastfed longer than girls, while the opposite trend is observed among families with fathers with lowest levels of education. Although the present study does not fully support the T‐W hypothesis, it gives evidence of greater investment in female offspring at the lower extremes of income, and greater investment in males at higher levels of income. Am J Phys Anthropol 115:71–79, 2001. © 2001 Wiley‐Liss, Inc.
Ontogeny of canine dimorphism in extant hominoids
Authors: Schwartz Gary T. , Dean Christopher
Published: August 2002

Many behavioral and ecological factors influence the degree of expression of canine dimorphism for different reasons. Regardless of its socioecological importance, we know virtually nothing about the processes responsible for the development of canine dimorphism. Our aim here is to describe the developmental process(es) regulating canine dimorphism in extant hominoids, using histological markers of tooth growth. Teeth preserve a permanent record of their ontogeny in the form of short‐ and long‐period incremental markings in both enamel and dentine. We selected 52 histological sections of sexed hominoid canine teeth from a total sample of 115, from which we calculated the time and rate of cuspal enamel formation and the rate at which ameloblasts differentiate along the future enamel‐dentine junction (EDJ) to the end of crown formation. Thus, we were able to reconstruct longitudinal growth curves for height attainment in male and female hominoid canines. Male hominoids consistently take longer to form canine crowns than do females (although not significantly so for our sample of Homo). Male orangutans and gorillas occasionally take up to twice as long as females to complete enamel formation. The mean ranges of female canine crown formation times are similar in Pan, Gorilla, and Pongo. Interspecific differences between female Pan canine crown heights and those of Gorilla and Pongo, which are taller, result from differences in rates of growth. Differences in canine crown heights between male Pan and the taller, more dimorphic male Gorilla and Pongo canines result both from differences in total time taken to form enamel and from faster rates of growth in Gorilla and Pongo. Although modern human canines do not emerge as significantly dimorphic in this study, it is well‐known that sexual dimorphism in canine crown height exists. Larger samples of sexed modern human canines are therefore needed to identify clearly what underlies this. Am J Phys Anthropol 115:269–283, 2001. © 2001 Wiley‐Liss, Inc.
Growth and ontogeny of sexual size dimorphism in the mandrill (Mandrillus sphinx)
Authors: Setchell Joanna M. , Lee Phyllis C. , Wickings E. Jean , Dixson Alan F.
Published: August 2002

We present body mass (N = 419) and crown‐rump length (CRL, N = 210) measurements from 38 male and 49 female mandrills born into a semifree‐ranging colony in order to describe growth from birth to adulthood, and to investigate maternal influences upon growth. Adult male mandrills are 3.4 times the body mass, and 1.3 times the CRL, of adult females. Body mass dimorphism arises from a combination of sex differences in length of the growth period (females attain adult body mass at 7 years, males at 10 years) and growth rate. Both sexes undergo a subadult growth spurt in body mass, and this is much more dramatic in males (peak velocity 551 g/months ± 89 SEM at 84–96 months). CRL dimorphism arises from bimaturism (females attain adult CRL at 6 years, males after 10 years), and neither sex shows a particular subadult growth spurt in CRL. Sexual size dimorphism thus represents important time and metabolic costs to males, who mature physically approximately 3–4 years after females. Considerable interindividual variation occurs in the size‐for‐age of both sexes, which is related to maternal variables. Older mothers have heavier offspring than do younger mothers, and higher‐ranking mothers have heavier offspring than do lower ranking mothers. Mass advantages conferred upon offspring during lactation by older and higher‐ranking mothers tend to persist postweaning in both sexes. Thus maternal factors affect reproductive success in both sexes, influencing the age at which offspring mature and begin their reproductive career. Am J Phys Anthropol 115:349–360, 2001. © 2001 Wiley‐Liss, Inc.
Lake pigments facilitate analysis of fecal cortisol and behavior in group‐housed macaques
Authors: Stavisky Ronda C. , Whitten Patricia L. , Hammett David H. , Kaplan Jay R.
Published: August 2002

Fecal steroid analyses are becoming more popular among both field and laboratory scientists. The benefits associated with sampling procedures that do not require restraint, anesthesia, and blood collection include less risk to both subject and investigator, as well as the potential to obtain endocrine profiles that do not reflect the influence of stress. However, the utility of the fecal steroid method has been limited in field conditions because of problems associated with sample identification. Here, we present evidence that Lake pigments are a valuable tool for the identification of individual fecal samples from group‐housed female cynomolgus macaques. Further, we present data that suggest that excreted cortisol can be assayed from such samples, leading to the finding that time of day of sample collection influences cortisol concentrations, with morning samples producing higher values (t = 2.769, P = 0.024). Finally, the collection of physiological data from group‐housed animals permits the evaluation of the relationship between endocrine status and behavior. This study demonstrated that morning fecal cortisol was significantly correlated with competitive and proximity behaviors, although not with rank in two stable social groups. In conclusion, the utility and validity of fecal steroid analyses continue to expand with further investigations. Am J Phys Anthropol 116:51–58, 2001. © 2001 Wiley‐Liss, Inc.
Association between high‐density lipoprotein and cognitive impairment in the oldest old
Authors: Van Exel Eric , de Craen Anton J. M. , Gussekloo Jacobijn , Houx Peter , Bootsma‐van der Wiel Annetje , Macfarlane Peter W. , Blauw Gerard J. , Westendorp Rudi G. J.
Published: August 2002

Low high‐density lipoprotein cholesterol is associated with an increased risk for cardiovascular disease and stroke. At the same time, cardiovascular disease and stroke are important risk factors for dementia. We assessed the association between total and fractionated cholesterol and cognitive impairment and explored whether observed associations were dependent on or independent of atherosclerotic disease. In a population‐based study, total cholesterol, triglycerides, low‐density lipoprotein cholesterol, and high‐density lipoprotein cholesterol were measured in 561 subjects 85 years old and grouped in three equal strata representing decreasing serum concentrations. History of cardiovascular disease and stroke was determined. All subjects completed the Mini‐Mental State Examination (MMSE), and the presence of dementia was determined. Median MMSE scores were significantly lower in subjects with low high‐density lipoprotein cholesterol (25 points vs 27 points, p < 0.001). No differences in MMSE scores were found for other lipids and lipoproteins. MMSE scores in subjects with and without cardiovascular disease were 26 and 27 points (p = 0.007), respectively, and in subjects with and without stroke were 21 and 26 points (p < 0.001), respectively. The associations between low MMSE scores and low high‐density lipoprotein cholesterol remained significant after subjects with cardiovascular disease or stroke were excluded. In a comparison of subjects with low high‐density lipoprotein cholesterol with subjects with high high‐density lipoprotein cholesterol, the odds ratio for dementia was 2.3 (95% confidence interval, 1.2–4.3), and in subjects without cardiovascular disease or stroke, it was 3.7 (95% confidence interval, 1.3–10.1). All odds ratios were unaffected by education, low‐density lipoprotein cholesterol, triglycerides, and survival. Low high‐density lipoprotein cholesterol is associated with cognitive impairment and dementia. At least part of the association between high‐density lipoprotein cholesterol and cognitive function is independent of atherosclerotic disease.
Neuroimmunophilins: Novel neuroprotective and neuroregenerative targets
Authors: Guo Xin , Dillman James F. , Dawson Valina L. , Dawson Ted M.
Published: August 2002

Cyclosporin A (CsA) and FK506 (tacrolimus) are immunosuppresants that are widely used in organ transplantation. CsA is an 11‐member cyclic peptide, whereas FK506 is a macrolide antibiotic. Recently, these powerful and useful compounds have become of great interest to neuroscientists for their unique neuroprotective and neuroregenerative effects. These drugs and nonimmunosuppressive analogs protect neurons from the effects of glutamate excitotoxicity, focal ischemia, and 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)‐induced dopaminergic cell death. They also stimulate functional recovery of neurons in a variety of neurologic injury paradigms. These drugs exert their effects via immunophilins, the protein receptors for these agents. The immunophilin ligands show particular promise as a novel class of neuroprotective and neuroregenerative agents that have the potential to treat a variety of neurologic disorders.
Ocular flutter associated with a localized lesion in the paramedian pontine reticular formation
Authors: Schon Fred , Hodgson Timothy L. , Mort Dominic , Kennard Christopher
Published: August 2002

Ocular flutter is a rare horizontal eye movement disorder characterised by rapid saccadic oscillations. It has been hypothesised that it is caused by loss of “pause” neuronal inhibition of “burst” neuron function in the paramedian pontine reticular formation (PPRF); however there have been no imaging studies confirming such anatomical localisation. We report the case of a woman with an acute attack of multiple sclerosis associated both with ocular flutter and a circumscribed pontine lesion, mainly involving the PPRF on magnetic resonance imaging. As she recovered from the attack, both the midline pontine lesion and the ocular flutter dramatically improved. This case is the first clear evidence that at least some cases of ocular flutter are due to lesions involving the PPRF.
Arsenic concentrations and speciation in a temperate mangrove ecosystem, NSW, Australia
Authors: Kirby J. , Maher W. , Chariton A. , Krikowa F.
Published: August 2002

Total arsenic concentrations and species were measured in the sediments, vegetation and tissues of marine animals from a temperate mangrove ecosystem. Mean arsenic concentrations ranged from 0.3 to 55 µg g−1 dry mass. Epiphytic algae/fungi associated with mangrove fine roots had relatively higher arsenic concentrations (12 ± 3 µg g−1) than mangrove leaves, bark or main roots (0.3–1.2 µg g−1) and algae/fungi attached to main roots (1.5 ± 0.8 µg g−1). The concentrations of arsenic in detritivores (8.5–55 µg g−1) were significantly higher than in the major primary producers (0.3–1.5 µg g−1), two herbivores (8 ± 1 and 14 ± 2 µg g−1) and omnivores (2–16.6 µg g−1). Most marine animal tissues contained large percentages of arsenobetaine (28–81%). Glycerol arsenoribose was found in all tissues examined (1–23%) except oyster tissues. Relatively large concentrations of this arsenoriboside were found in the digestive tissues of two crab species (13–23%). Small amounts of trimethylarsoniopropionate (1–8%), tetramethylarsonium ion (1–7%), sulfate arsenoribose (2–13%) and trace amounts of arsenocholine (<1%), trimethylarsine oxide (<1%), dimethylarsinic acid (<2%), phosphate arsenoribose (<2%), arsenate (<1%), and sulfonate arsenoribose (<3%) were found in some tissues. Methylarsonic acid was not found in any tissues. Two unknown cationic arsenic compounds (1–2%) and three anionic arsenic compounds (1–17%) were present in some marine animal tissues. The arsenic concentrations and species found in animals could not be attributed to their position in the food web or feeding mode, but are likely to be related to their dietary intake of arsenic and their ability to assimilate, metabolize and retain arsenic species. Copyright © 2002 John Wiley & Sons, Ltd.
Biomethylation of bismuth by the methanogen Methanobacterium formicicum
Authors: Michalke Klaus , Meyer Jörg , Hirner Alfred V. , Hensel Reinhard
Published: August 2002

In this study the bioconversion of bismuth to volatile derivatives was investigated in cultures of the common sewage sludge methanogen Methanobacterium formicicum. The production of volatile bismuth compounds was analysed during growth of M. formicicum with respect to the concentration and chemical formulation of the applied bismuth. The main volatile bismuth compound detected in the culture headspace was trimethylbismuth (TMBi), with a maximum conversion rate of up to 2.6 ± 1.8% from spiked 1 µM bismuth nitrate [Bi(NO3)3] in the culture media. This main compound proved to be stable under the incubation conditions in a CO2–H2 atmosphere. Bismuthine and the partially methylated bismuthines monomethylbismuth hydride and dimethylbismuth hydride were additionally detected in the late exponential growth phase, but only in the presence of low concentrations of spiked Bi(NO3)3 (10 nM, 100 nM). The conversion of bismuth to TMBi from the bismuth‐containing pharmaceuticals Bismofalk® [containing bismuth subgallate and Bi(NO3)3] and Noemin® (containing bismuth aluminate) could also be observed, however, with a lower rate than found for Bi(NO3)3. In vitro experiments with crude extracts of M. formicicum suggest that the methylation of bismuth is mainly catalysed by enzyme‐catalysed reactions with methylcobalamin as methyl donor. Copyright © 2002 John Wiley & Sons, Ltd.
Thermal cure monitoring of phenolic resole resins based on in situ fluorescence technique
Authors: Vatanparast Ramin , Li Shuyan , Hakala Kati , Lemmetyinen Helge
Published: August 2002

The thermal curing reaction of two phenolic resole resins is monitored using the fluorescence technique. The intrinsic fluorescence can be used as an indicator for cure monitoring for the first resole. As the thermal curing proceeds, the intrinsic fluorescence intensity of the resole resin decreases and exhibits a few nanometers of redshift. The fluorescence intensity of the emission maxima is correlated with the conversion measured by differential scanning spectroscopy. A linear correlation is found at three different temperatures. The intrinsic fluorescence cannot always be used for monitoring the curing process of phenolic resole resins. Thus, three intramolecular charge transfer compounds and two organic donor–π‐acceptor salts are selected and applied for the cure monitoring of the second phenolic resole resin. As the curing reaction proceeds, the fluorescence emission spectra of the probes exhibit a blue spectral shift and the intensity changes because of environmental changes. An intensity ratio method is applied in which the ratios of the low‐ to high‐intensity changes in the emission bands are used to determine the degree of the curing process. There is a smooth correlation between the intensity ratio method and the degree of cure. The method enables one to follow the changes in the polymer structure at low and intermediate degrees of the curing process (below 70%) and obtain comparable results from different types of probes during the same curing process. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1773–1780, 2002
Microporous membranes of isotactic poly(4‐methyl‐1‐pentene) from a melt‐extrusion process. I. Effects of resin variables and extrusion conditions
Authors: Johnson Matthew B. , Wilkes Garth L.
Published: August 2002

A study utilizing isotactic poly(4‐methyl‐1‐pentene) (PMP) was undertaken to investigate a three‐stage process (melt‐extrusion/annealing/uniaxial‐stretching) (MEAUS) employed to produce microporous films. The results of this study will be reported in the course of two articles. In this first part, three PMP resins were melt‐extruded into tubular films (blowup ratio; BUR = 1), where the resins each differ in weight‐average molecular weight (Mw). Specific attention was focused upon the morphological and crystal orientation results as a function of the melt‐relaxation times as influenced by the resin characteristics and the processing parameters. The results of a number of melt‐extrusion conditions are presented. A stacked lamellar morphology was obtained in each case; however, the type of stacked lamellar morphology, planar or twisted, and the orientation state was found to depend upon both the resin characteristics, specifically Mw, and the melt‐extrusion conditions. Atomic force microscopy and wide‐angle X‐ray scattering (WAXS) were the main techniques utilized to study the melt‐extruded films, while oscillatory shear measurements, in conjunction with a Carreau–Yasuda analysis, aided in differentiating the melt‐flow behavior of the three resins. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2095–2113, 2002
Iron(III) ion removal from solution through adsorption on chitosan
Authors: Burke A. , Yilmaz E. , Hasirci N. , Yilmaz O.
Published: August 2002

The potential of different forms of chitosan to adsorb iron(III) ion from a Jectofer [an iron(III)–sorbitol–citric acid complex] solution was investigated. The working solution was chosen as Jectofer, to mimic the composition of excess iron(III) as may be found in biological systems. The equilibrium studies showed that chitosan powder has the highest sorption capacity for the iron(III) ion when compared to chitosan flakes and microspheres. The amount of iron(III) adsorbed onto chitosan was found to increase with the contact time to reach equilibrium within 3 h at 37°C. A higher initial concentration of a Jectofer solution resulted in a higher amount of iron(III) adsorbed. Higher pH values, in the range 2–7, also resulted in an increase in iron(III) uptake from the solution. The data of adsorption from the Jectofer solution were found to correlate well with the Freundlich isotherm equation. In vitro adsorption experiments showed that chitosan is capable of adsorbing excess iron, measured in terms of the ferritin level, in human blood. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1185–1192, 2002; DOI 10.1002/app.10416
Three‐dimensionally braided carbon fiber–epoxy composites, a new type of material for osteosynthesis devices. I. Mechanical properties and moisture absorption behavior
Authors: Wan Y. Z. , Wang Y. L. , Cheng G. X. , Han K. Y.
Published: August 2002

In recent years, three‐dimensionally (3D) braided composites have attracted a great deal of attention because of their high‐impact damage tolerance and fatigue life, superior fracture toughness, and so forth, and have been used in aeronautics, military, and transportation. These advantages make them strong candidates for osteosynthesis devices. In this study, 3D braided carbon fiber–epoxy (C3D/EP) composites were produced via a simple vacuum impregnation technique. The load‐deflection curve, mechanical properties, and influence of fiber volume fraction, braiding angle, and axial reinforcing fibers were examined to determine their suitability for internal fixation devices. It is found that the C3D/EP composites have excellent toughness and do not show brittleness when fractured because of their relatively high void content. The flexural, shear, and impact strengths of the C3D/EP composites are excellent. It was shown that a C3D/EP composite with a stiffness similar to load‐bearing bones can be made while maintaining enough strength. It is concluded that a relatively higher void content and braiding angle is more suitable for the C3D/EP composites from the viewpoint of requirements of fracture fixation materials. The moisture absorption behavior and changes in mechanical properties caused by moisture uptake were evaluated. Results show that absorbed moisture slightly decreases mechanical properties of the C3D/EP composites. Contrary to the unreinforced epoxy, the moisture absorption behavior of the C3D/EP composites cannot be described with Fick's law of diffusion, probably because of the presence of voids and/or 3D fiber structure. The exact mechanisms should be proposed in further investigations. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1031–1039, 2002
Physical and mechanical properties of polyethylene for pipes in relation to molecular architecture. II. Short‐term creep of isotropic and drawn materials
Authors: Hubert L. , David L. , Séguéla R. , Vigier G. , Corfias‐Zuccalli C. , Germain Y.
Published: August 2002

Tensile drawing and short‐term creep of ethylene/α‐olefin copolymers having bimodal (BM) molar weight distribution are studied in comparison with unimodal (UM) copolymers of similar crystallinity. The natural draw ratio and viscoelastic recovery upon unloading strongly suggest that BM copolymers have more tie chains and chain entanglements than corresponding UM copolymers. The incorporation of co‐units in the longest chains of BM copolymers is ascribed a major role on these topological changes. Creep of isotropic materials shows lower compliance for BM copolymers in parallel with higher‐durability grades. This is attributed to a better “macromolecular network efficiency.” The creep behavior of strain‐hardened samples, which is assumed to simulate the mechanical behavior of craze fibrils at the tip of a propagating crack, reveals similar trends. The better fibril strength in BM copolymers is again ascribed to a better network efficiency. Necked samples display an odd behavior of higher compliance at low stress and lower compliance at high stress for BM copolymers compared with the behavior of UM counterparts. This is associated with the exhaustion of viscoelastic capabilities with increasing draw ratio and stress. The phenomenon is discussed in relation to cavitation. A short‐term creep test is proposed for comparative prediction of long‐term behavior. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2308–2317, 2002
Morphology and micromechanical deformation behavior of styrene/butadiene‐block copolymers. I. Toughening mechanisms in asymmetric star block copolymers
Authors: Michler G. H. , Adhikari R. , Lebek W. , Goerlitz S. , Weidisch R. , Knoll K.
Published: August 2002

Lamellae‐forming styrene/butadiene star block copolymers are studied to investigate the influence of morphology on micromechanical deformation mechanisms and mechanical properties by using transmission electron microscopy and tensile testing. A large homogeneous plastic deformation of polystyrene (PS) lamellae is found in styrene/butadiene star block copolymers on the basis of the new mechanism called thin‐layer yielding. This mechanism depends strongly on the thickness of the PS lamellae. At a critical thickness of PS lamellae of about 20 nm, a transition from thin‐layer yielding mechanism to a crazelike deformation was observed. These new deformation zones are similar to crazes with respect to their propagation perpendicular to direction of external stress and similar to shear bands with respect to an internal shear deformation component of the lamellae in the deformation zones. As a result of our investigations, the mechanical properties of star block copolymers can be understood in correlation with morphology and micromechanical deformation mechanisms. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 683–700, 2002
Thermal and mechanical properties of the polymers synthesized by the sequential polymerization of propylene and 1‐hexadecene
Authors: Jeong Han Mo , Lee Shang Hoon , Cho Kwang Jae , Jeong Young Tae , Kang Kap Ku , Oh Jae Kwon
Published: August 2002

The block copolymer of poly(1‐hexadecene) (PHD) and polypropylene (PP) was effectively synthesized by the sequential polymerization of propylene and 1‐hexadecene by using highly isospecific TiCl3/Cp2Ti(CH3)2 (Cp = cyclopentadienyl). The block copolymers had two separate melting temperatures of constituent blocks. The modulus of PHD–PP block copolymer was enhanced as the content of sequentially polymerized PP block was increased. The elongation at break showed positive deviation at the intermediate compositions from the simple additive values of constituent homopolymers. Shape memory effect which utilizes the crystalline PHD block as a reversible phase and the crystalline PP block as a fixed structure was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1709–1715, 2002; DOI 10.1002/app.10551
Preparation and properties of soluble copolysulfoneimide and performance of solvent‐resistant ultrafiltration membrane
Authors: Kim In‐Chul , Kim Jong‐Ho , Lee Kew‐Ho , Tae‐Moon
Published: August 2002

Soluble copolysulfoneimides were synthesized by thermal two‐step method in solution of N‐methyl‐2‐pyrrolidone. The used aromatic diamines were bis[4‐(3‐aminophenoxy)phenyl]sulfone (BAPS‐m) and 3,3′‐diaminosulfone, and dianhydrides were pyromellitic dianhydride, 4,4′‐oxyphthalic anhydride, and 3,3′,4,4′‐diphenylsulfone tetracarboxylic dianhydride. The molar ratio of diamines was changed to reduce the content of BAPS‐m. The thermal and mechanical properties of polyimides were investigated. The polyimide ultrafiltration membrane with molecular weight cut‐off of 10 kDa could be successfully prepared by phase‐inversion method. Various solvent (water, alcohols, acetone, and hexane) fluxes were measured to investigate solvent‐resistance and membrane behavior during solvent permeation. The activation energy relationship between hexane flux and viscosity with temperature was also studied. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1024–1030, 2002
Determination of tacticity in polypropylene by FTIR with multivariate calibration
Authors: Ozzetti Rafael A. , De Oliveira Filho Antonio Pedro , Schuchardt Ulf , Mandelli Dalmo
Published: August 2002

A method for determination of tacticity in polypropylene (PP) using FTIR associated with multivariate analysis is presented. Blends of PP with known tacticity were prepared with isotactic, syndiotactic, and atactic polymer and analyzed by 13C‐NMR. The FTIR spectra were recorded and processed through principal components regression (PCR) and partial least‐squares regression (PLS), using information from several different portions of the spectra. The method was compared with the classical methods of tacticity determination by FTIR based on the intensities of the bands at 998 cm−1 (isotactic), 868 cm−1 (syndiotactic), and 975 cm−1 (internal standard), which are known to be dependent on the crystallinity of the polymer and, thus, affected by temperature and sample preparation. The models obtained with multivariate calibration, both with PCR and PLS, gave prediction errors up to fivefold smaller than that of the classical methods, and were also shown not to be heavily dependent on the bands that are affected by the crystallinity of the polymer, but rather on the methyl and methylene bendings at 1375 and 1462 cm−1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 734–745, 2002
Reverse atom transfer radical polymerization of stearyl methacrylate using 2,2′‐azobisisobutyronitrile as the initiator
Authors: Saikia Prakash J. , Goswami Aradhana , Baruah Shashi D.
Published: August 2002

The living/controlled radical polymerization of stearyl methacrylate was carried out with a conventional radical initiator (2,2′‐azobisisobutyronitrile) in N,N‐dimethylformamide in the presence of a 2,2′‐bipyridine complex of hexakis(N,N‐dimethylformamide)iron(III) perchlorate. The polymerization mechanism was thought to proceed through a reverse atom transfer radical polymerization. The molecular weights of resulting poly(stearyl methacrylate) increased with conversion, and the resulting molecular weight distributions were quite narrow. The rates of polymerization exhibited first‐order kinetics with respect to the monomer. A probable reaction mechanism for the polymerization system is postulated to explain the observed results. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1236–1245, 2002
Heat treatment‐induced multiple melting behavior of carbon black‐filled polymer blends in relation to the conductive performance stabilization
Authors: Hou Yan Hui , Zhang Ming Qiu , Mai Kan Cheng , Rong Min Zhi , Yu Gang , Zeng Han Min
Published: August 2002

Polymer blend‐based electrical conductive composites are provided with more possibilities for tailoring the performance in comparison with single polymer systems. To find an optimum heat treatment temperature of the composites, which is critical to practical applications, detailed thermal analyses of the related materials were carried out as a function of different annealing conditions. Based on the discussion of the morphological variation during treatment in terms of multiple melting behavior, it was found that an annealing temperature of 75°C is able to stabilize the resistivity of the composites within a reasonable period of time, as only solid‐state crystallization of LDPE and uniformization of EVA crystalline size are involved. In contrast to treatment at a temperature higher than 75°C, the ultimate equilibrium resistivity resulting from the above annealing procedure approaches the resistivity of the composites as‐manufactured. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1267–1273, 2001
In situ study of the dynamics of erosion of carbon black agglomerates
Authors: Seyvet Olivier , Navard Patrick
Published: August 2002

With the help of a counter‐rotating transparent rheometer equipped with an optical microscope, the erosion of single, commercial carbon black agglomerates suspended in a polyisobutylene fluid was accurately recorded in situ. We observed that clouds of very small aggregates were leaving the agglomerate at 45 and 225° in the shear gradient–flow direction plane, where the stress is maximum. The distribution of the arrached aggregates is more efficient when the carbon black agglomerate is more asymmetric. A spherical agglomerate of critical radius R0 will reach a radius Rt at time t following R − R = at, a being a constant. This implies that the rate at which the number of aggregates is leaving the agglomerate is a constant, independent of the size of the agglomerate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1627–1629, 2001
Recycled old newsprint fibers as a reinforcing filler in molded polyester composites
Authors: Hassan Mohammad L. , Nada Abd‐Alla M. A.
Published: August 2002

Using old newsprint (ONP) fibers as reinforcing filler in polyester (PE) composite has been studied. Using ONP fibers in PE composite resulted in a decrease in modulus of rupture (MOR) and an increase in modulus of elasticity (MOE) and tensile strength as compared with a neat PE composite. Also, water absorption and thickness swelling were increased as a result of using ONP fibers in the composite. Acetylation, steaming, and esterification (using maleic anhydride) of ONP fibers were performed to improve the dimensional stability of the produced composite. Acetylation and steaming of ONP fibers resulted in a decrease in the thickness swelling of the produced composites; MOR, MOE, and tensile strength were also decreased as a result of these treatments. Esterification of ONP fibers using maleic anhydride resulted in a decrease in thickness swelling of the produced composite and, at the same time, an increase in MOR, MOE, and tensile strength. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2018–2023, 2001
Graft copolymerization of acrylic acid onto cellulose: Effects of pretreatments and crosslinking agent
Authors: Gürdağ Gülten , Güçlü Gamze , Özgümüş Saadet
Published: August 2002

The graft copolymerization of acrylic acid (AA) and 2‐acrylamido 2‐methylpropane sulfonic acid (AASO3H) onto cellulose, in the presence or absence of crosslinking agent N,N′‐methylene bisacrylamide (NMBA), by using different concentrations of ceric ammonium nitrate (CAN) initiator in aqueous nitric acid solution at either 5 or 30°C was investigated. To investigate the effect of pretreatment of cellulose on the copolymerization, before some grafting reactions cellulose was pretreated with either 2 or 20 wt % NaOH solutions or heated in distilled water/aqueous nitric acid (2.5 × 10−3 M) at 55°C. To determine how the excess of initiator affects the grafting and homopolymerization, separate reactions were carried out by removing the excess of ceric ions by filtration of the mixture of initiator solution and cellulose before the monomer addition. Extraction‐purified products were characterized by grafting percentage and equilibrium swelling capacity. Pretreatment of cellulose with NaOH solutions decreased the grafting percentage of copolymers. In the case of AA–AASO3H mixtures, nonpretreated cellulose gave a higher grafting percentage than NaOH‐pretreated cellulose. Filtration also lowered the grafting of AA on the cellulose in the cases of pretreatment with either water or nitric acid. Copolymers with the highest grafting percentage (64.8%) and equilibrium swelling value (105 g H2O/g copolymer) were obtained in grafting reactions carried out in the presence of NMBA at 5°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2267–2272, 2001
Preparation and characterization of electroconductive polypyrrole–thermoplastic composites
Authors: Castillo‐Ortega M. M. , Encinas J.C. , Rodríguez D. E. , Olayo R.
Published: August 2002

Polypyrrole–thermoplastic composite films were obtained by casting. Homogeneous films were prepared with dispersant poly(vinyl methyl ether) or poly(vinyl ethyl ether) by two methods. Electric conductivity, morphology, mechanical properties, and sensitivity to H2O2 in water were studied. Composites of polypyrrole with poly(vinyl chloride) carboxylated and poly(vinyl methyl ether) presented improved mechanical and electrical properties compared with other composites studied. These films were sensitive to H2O2 in water, showing a significant change in electric resistance. This change is discussed in relation to the H2O2 concentration and the exposure time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1498–1506, 2001
Effect of zone drawing on the structure and properties of melt‐spun poly(trimethylene terephthalate) fiber
Authors: Lyoo Won Seok , Lee Hyun Seok , Ji Byung Chul , Han Sung Soo , Koo Kang , Kim Sam Soo , Kim Joon Ho , Lee Joon‐Seok , Son Tae Won , Yoon Won Sik
Published: August 2002

Melt‐spun poly(trimethylene terephthalate) (PTT) fibers were zone‐drawn and the structures and properties of the fibers were investigated in consideration of the spinning and zone‐drawing conditions. The draw ratio increased up to 4 with increasing drawing temperature to 180°C, at a maximum drawing stress of 220 MPa. Higher take‐up velocity gave lower drawability of the fiber. The PTT fiber taken up at 4000 rpm was hardly drawn, in spite of using maximum drawing stress, because a high degree of orientation had been achieved in the spinning procedure. However, an additional enhancement of birefringence was observed, indicating a further orientation of PTT molecules by zone drawing. The exotherm peak at 60°C disappeared and was shifted to a lower temperature with an increase in the take‐up velocity, which means that the orientation and crystallinity of the fiber increased. The d‐spacing of (002) plane increased with increasing take‐up velocity and draw ratio, whereas those of (010) and (001) planes decreased. In all cases, the crystal size increased with take‐up velocity and draw ratio. The cold‐drawn PTT fiber revealed a kink band structure, which disappeared as the drawing temperature was raised. The physical properties of zone‐drawn PTT fibers were improved as the draw ratio and take‐up velocity increased. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3471–3480, 2001
Influence of degree of crystallinity and syndiotacticity on infrared spectra of solid PVA
Authors: Sugiura Kentaroh , Hashimoto Morio , Matsuzawa Shuji , Yamaura Kazuo
Published: August 2002

The influence of the degree of crystallinity and the syndiotacticity on the 1145, 1095, and 916 cm−1 bands was studied. The intensity of the 1145 cm−1 band increased with increasing syndiotacticity at a low degree of crystallinity and with an increasing degree of crystallinity for a sample with syndiotacticity. The intensity of 1095 cm−1 band increased with increasing syndiotacticity at a fixed degree of crystallinity and was independent of the degree of crystallinity for a sample. The intermolecular hydrogen bonds were found to play an important role. The differences of the relations between the absorbance ratio D1145/D1095 and the degree of crystallinity with syndiotacticity were explained. The extent of the decrease of the intensity of 916 cm−1 band with an increasing degree of crystallinity increased with decreasing syndiotacticity. The predominant introduction of syndiotactic sequences in the crystals was assumed in the lower syndiotacticity. The improved equation between the syndiotactic diad content in percent [s‐(diad) %] and the absorbance ratio D916/D849 was established as s‐(diad) % = 71.1 × (D916/D849)0.327 for the films heated at 50°C with use of a syndiotactic diad content obtained from NMR spectra. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1291–1298, 2001
Biologically active polymers. IV. Synthesis and antimicrobial activity of polymers containing 8‐hydroxyquinoline moiety
Authors: Kenawy El‐Refaie
Published: August 2002

Polymers containing 8‐hydroxyquinoline moiety were prepared. Modifications of the base polymer of glycidyl methacrylate were carried out in order to introduce chloromethyl groups, either by the hydrolysis of the poly(glycidyl methacrylate) and the chloroacetylation of the hydrolyzed polymer by the reaction with chloroacetyl chloride or by aminating the poly(glycidyl methacrylate) either with ethylenediamine or with hexamethylenediamine, followed by reacting the aminated polymers with chloroacetyl chloride. The polymers containing 8‐hydroxyquinoline moiety were prepared by reacting the chloromethyl groups containing polymers with potassium salt of 8‐hydroxy quinoline. The antimicrobial activity of the polymers obtained was examined against gram‐negative bacteria (Escherichia coli) and gram‐positive bacteria (Bacillus subtilus) as well as the fungus Trichophyton rubrum. Generally, all three polymers proved effective against the tested microorganisms, but growth inhibitory effects varied from one another. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1364–1374, 2001
Heat setting of stretched and microvoided PE/CaCO3 films
Authors: Hale W. R. , McGuire J. , Sand I. D. , Dohrer K. K.
Published: August 2002

Calcium‐carbonate‐filled linear low‐density polyethylene (LLDPE) films play an important role in the hygienics market because these materials allow for the diffusion of water vapor (breathability) and retain a liquid barrier while providing a barrier to liquids. This is achieved when properly formulated composites are stretched to create pores. There are many important issues surrounding this technology; this report focuses on the effects of poststretching heat‐set treatment on moisture vapor transmission rate (MVTR), dynamical mechanical thermal analysis (DMTA), tensile heat distortion temperature (THDT), and differential scanning calorimetry (DSC) thermal transitions of the porous film properties. Eastman personnel provided the LLDPE/CaCO3 breathable films for this study. In general, the film properties were insensitive to heat‐setting time beyond that of 1 min. This result suggests that the molecular reorientation and recrystallization associated with the changes in film properties occur rapidly. Properties were, however, strongly sensitive to the heat‐set temperature when MVTR decreased and DMTA properties [specifically storage modulus (E′) and the α‐transition temperature] increased as the heat‐set temperature increased. This is believed to have been mainly caused by pore closure and the annealing of crystalline regions. The heat‐set temperature was easily detectable by DSC techniques when a thermal transition was apparent at the applied temperature, and changes in the heat of fusion for the sample could be observed. Ultimately, the changes in the properties of these porous films were related to changes in the molecular orientation and crystallinity of the matrix in combination with changes in the void structure of the composite. In particular, changes in E′ could be related to these separate effects. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2454–2471, 2001