bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple‐threshold models for genetic influences on age of onset for Alzheimer disease: Findings in Swedish twins
Authors: Pedersen Nancy L. , Posner Samuel F. , Gatz Margaret 
Published: August 2002

AbstractTwin studies of dementia have typically used relatively simple 2 × 2 contingency tables with one threshold to estimate the relative importance of genetic variance for liability to disease. These designs are inadequate for addressing issues of age at onset, censoring of data, and distinguishing shared environmental effects from age effects. Meyer and Breitner [1998: Am J Med Genet 81:92–97] applied a multiple‐threshold model to the NAS‐NRC Twin Panel (average age of onset, 63.5 years) and report that additive genetic effects and shared environmental effects account for 37% and 35% of the variation, respectively, in age of onset for Alzheimer disease. We apply a modified version of their model to the Study of Dementia in Swedish Twins (average age of onset, 75 years) and find that genetic effects account for 57%–78% of the variance, whereas shared environmental effects are of no importance. Heritability is lower when thresholds are freely estimated rather than fixed to the population prevalences. We interpret the findings to suggest that models with free thresholds confound influences on longevity with influences for the disease. Multiple‐threshold models, however, do not confound age effects with shared environmental influences. © 2001 Wiley‐Liss, Inc.
Changes in biological anthropology: Results of the 1998 American Association of Physical Anthropology Membership Survey
Authors: Turner Trudy R. 
Published: August 2002

AbstractIn response to the results of the 1996 survey of the membership of the American Association of Physical Anthropology (AAPA), the Executive Committee of the Association sponsored a follow‐up survey designed to assess gender and specialty differences in training, employment, academic status, mentoring, and research support. A total of 993 questionnaires was analyzed, representing approximately 62% of the 1998 membership of the Association. There has been a marked shift in the number of males and females in the discipline from the 1960s to the 1990s. While 51.2% of all respondents are female and 48.8% are male, 70% of the students are female. Chi‐square tests indicate significant differences between males and females by highest degree, age, status, obtaining a tenure‐track position, receiving tenure, and taking nontenure‐track employment before receiving a tenure‐track position. In recent years, there has been an increasing number of females in the ranks of assistant and associate professors; however, this is not true for the rank of professor. There are also significant differences between males and females by specialty within the discipline: researchers in primatology, human biological variation, skeletal biology, and paleopathology are primarily female, while researchers in human and primate evolution are increasingly female. Am J Phys Anthropol 118:111–116, 2002. © 2002 Wiley‐Liss, Inc.
Serum insulin‐like growth factor‐I, insulin‐like growth factor binding protein‐3, and the pubertal growth spurt in the female rhesus monkey
Authors: Ulijaszek Stanley J. 
Published: August 2002

AbstractWhile there is good evidence suggesting IGF‐I links to pubertal development and crown‐rump length growth among rhesus monkeys, linkages between IGF‐I and other measures of morphological growth have not been established. In this study, the pubertal growth spurt in a number of morphological characteristics of female rhesus monkeys is related to serum endocrine status of insulin‐like growth factor‐I (IGF‐I) and its binding protein, insulin‐like growth factor binding protein‐3 (IGFBP‐3), to test the hypothesis that elevations in IGF‐I and IGFBP‐3 coincide with the time of greatest growth rate of different morphological characteristics. A longitudinal study of pubertal growth among four female rhesus monkeys was carried out across a 3‐year period. Morphometric measurements included weight, crown‐rump length, foot‐length, and skinfolds at five sites (biceps, triceps, abdominal, subscapular, and suprailiac). These measures were taken as being representative of total mass, skeletal growth of the trunk and head, limb length, and body fatness, respectively. Measurements were carried out as closely as possible to 3‐monthly, with interpolations being performed to standardise the data to exactly 3‐monthly intervals for all individuals. Blood samples were taken at time of morphometry. Elevations in serum IGF‐I and IGFBP‐3 took place in a manner similar to that of humans, and across the period associated with onset of puberty. Mean 3‐monthly gain in crown‐rump length and foot length showed significant peaks across the measurement period, while mean 3‐monthly gains in weight and sum of five skinfolds did not. Greatest foot length gain occurred on average between 3–3.5 years of age, while crown‐rump length gain was greatest between 3.75–4 years of age. Periods of greatest gain in crown‐rump length and foot length took place across the period of elevated serum IGF‐I levels, which was between 3–4.5 years of age. Significant elevations in IGF‐I and IGFBP‐3 were not coincident with greatest gains in foot length or crown‐rump length. Thus the hypothesis does not hold true for the two measures showing significant peaks in 3‐monthly gain across the measurement period. The nature of the endocrine impact on macaque morphology remains unclear, although this may be fundamental to the understanding of the variation in the pubertal growth spurt and its influence on morphology at maturity both within and across primate species. Am J Phys Anthropol 118:77–85, 2002. © 2002 Wiley‐Liss, Inc.
Osteobiographic analysis of skeleton I, Sítio Toca dos Coqueiros, Serra da Capivara National Park, Brazil, 11,060 BP: First results
Authors: Lessa Andrea , Guidon Niéde 
Published: August 2002

AbstractThis paper presents an osteobiographic analysis of a single skeleton found in a small rock shelter known as Toca dos Coqueiros, Piauí, Brazil. This find is of interest because of an exceptionally old radiocarbon date associated with it. The date (11,060 BP) was obtained from charcoal associated directly with the skeleton. This is an interesting find because of the rarity of osteobiographic studies of skeletons of such antiquity. Despite the existence of two projectile points in association with the burial, the morphological and molecular analyses of the skeleton demonstrated that this was a female. She was about 35–45 years of age at death. The skeleton exhibited acute and chronic bone lesions. Oral pathology was also observed, including an interproximal dental groove, probably caused by the therapeutic use of a cactus thorn. This could be one of the oldest cases of an analgesic plant used in the prehistoric Americas. Am J Phys Anthropol 118:99–110, 2002. © 2002 Wiley‐Liss, Inc.
Production of dimethyl telluride and elemental tellurium by bacteria amended with tellurite or tellurate
Authors: Basnayake Rukma S. T. , Bius Janet H. , Akpolat Osman M. , Chasteen Thomas G. 
Published: August 2002

AbstractThe purpose of this study was to determine whether a facultative anaerobe, Pseudomonas fluorescens K27, would produce dimethyl telluride when anaerobic cultures were amended with differing concentrations of sodium tellurate and/or sodium tellurite and how that volatile organotellurium production varied over time. Batch bacterial bioreactor experiments were undertaken in order to observe the changes in the headspace of a growth medium solution inoculated with P. fluorescens and amended with tellurium salts. Gas samples were taken from the bioreactor every hour and were analyzed by capillary gas chromatography using fluorine‐induced chemiluminescence detection to determine compounds in the headspace. Liquid samples were analyzed by spectrophotometer to determine optical densities, which were used as an indicator of cell growth. Verification of the identity of the dimethyl telluride produced in the bacterial headspace above a tellurate‐amended culture was achieved by comparison with the chromatographic retention time of an authentic (CH3)2Te standard and by gas chromatography/mass spectrometry. The time course production of dimethyl telluride varied with amendment salts' tellurium oxidation states and concentrations. Increasing tellurate concentrations caused slower bacterial growth, but those cultures reached the stationary phase sooner than cultures amended with tellurite concentrations 10 or 100 times less. Black elemental tellurium (Te0) was produced by live cultures amended with tellurium salts but not by sterile controls. The amount of tellurium in the solid phase (as Te0 and in/or on cells) harvested from replicate, anaerobic cultures of P. fluorescens sampled after 92 h of incubation was approximately 34%. Mixed tellurite/tellurate amendment experiments exhibited a synergistic toxic effect and yielded less final biomass and very little dimethyl telluride production compared with cultures amended with either tellurate or tellurite alone. Copyright © 2001 John Wiley & Sons, Ltd.
Speciation and detection of organotins from PVC pipe by micro‐liquid chromatography–electrospray–ion trap mass spectrometry
Authors: Jones‐Lepp T. L. , Varner K. E. , Hilton B. A. 
Published: August 2002

AbstractThis paper describes the application of a micro‐liquid chromatography–electrospray–ion trap mass spectrometry (µ‐LC–ES–ITMS) method for separation and detection of organotin compounds leached from potable‐water polyvinyl chloride (PVC) pipe. Dibutyltin (DBT) is added as a heat stabilizer to PVC. DBT was determined in 1 l water samples that had remained static in PVC pipes over several days (totaling 96 h). Other organotin compounds in the leachate were screened for, by using µ‐LC–ES–ITMS. An initial level of approximately 1 µgl−1 of DBT resulted within 24 h, with a subsequent drop and then a rise in DBT levels over the next 96 h to 0.8 µgl−1. Published in 2001 by John Wiley & Sons, Ltd.
Speciation of phenyltin(IV) compounds using high‐performance liquid chromatography: Part 1. The direct analysis of mixed standard solutions of tetraphenyltin, triphenyltin chloride, triphenyltin hydroxide and triphenyltin acetate
Authors: Lal Shobha K. , Tan G. H. , Tioh N. H. , Kumar Das V. G. 
Published: August 2002

AbstractA rapid speciation high‐performance liquid chromatography (HPLC) method has been developed for the simultaneous determination of phenyltin compounds. The commercially important products of triphenyltin‐chloride, ‐acetate, ‐hydroxide and tetraphenyltin were separated by reversed‐phase HPLC on a Waters Spherisorb S5W ODS‐2 (octadecylsilica) column using an isocratic mixture of 90:10 (v/v) acetonitrile:water as the mobile phase at a flow rate of 1 ml min−1. The phenyltin compounds were detected by UV detection at 254 nm and the total elution time is 8 min. The elution order is triphenyltin‐chloride, ‐acetate, ‐hydroxide and tetraphenyltin. Detection limits were 0.01 ppm for each of the triphenyltin compounds and 0.02 ppm for tetraphenyltin. Spiked water samples containing the three biocidal triphenyltin compounds could also be analysed simultaneously by the above method without the need for any prior derivatization, following extraction with toluene. The versatility of the method in sensing substituent group variations on the phenyl ring was also demonstrated by the successful resolution of the hydroxides, tris(p‐chlorophenyl)tin hydroxide, diphenyl(p‐chlorophenyl)tin hydroxide and triphenyltin hydroxide. Copyright © 2002 John Wiley & Sons, Ltd.
Organoarsenic compounds in plants and soil on top of an ore vein
Authors: Geiszinger Anita , Goessler Walter , Kosmus Walter 
Published: August 2002

AbstractPlants and soil collected above an ore vein in Gasen (Austria) were investigated for total arsenic concentrations by inductively coupled plasma mass spectrometry (ICP‐MS). Total arsenic concentrations in all samples were higher than those usually found at non‐contaminated sites. The arsenic concentration in the soil ranged from ∼700 to ∼4000 mg kg−1 dry mass. Arsenic concentrations in plant samples ranged from ∼0.5 to 6 mg kg−1 dry mass and varied with plant species and plant part. Examination of plant and soil extracts by high‐performance liquid chromatography–ICP‐MS revealed that only small amounts of arsenic (<1%) could be extracted from the soil and the main part of the extractable arsenic from soil was inorganic arsenic, dominated by arsenate. Trimethylarsine oxide and arsenobetaine were also detected as minor compounds in soil. The extracts of the plants (Trifolium pratense, Dactylis glomerata, and Plantago lanceolata) contained arsenate, arsenite, methylarsonic acid, dimethylarsinic acid, trimethylarsine oxide, the tetramethylarsonium ion, arsenobetaine, and arsenocholine (2.5–12% extraction efficiency). The arsenic compounds and their concentrations differed with plant species. The extracts of D. glomerata and P. lanceolata contained mainly inorganic arsenic compounds typical of most other plants. T. pratense, on the other hand, contained mainly organic arsenicals and the major compound was methylarsonic acid. Copyright © 2002 John Wiley & Sons, Ltd.
Morphology and physical properties of closed cell microcellular ethylene–octene copolymer: Effect of precipitated silica filler and blowing agent
Authors: Nayak N. C. , Tripathy D. K. 
Published: August 2002

AbstractThe morphology of the microcellular ethylene–octene copolymer (Engage) of both unfilled and precipitated silica‐filled compounds was studied from SEM photomicrographs with variation of blowing agent and silica filler loading. The average cell size, maximum cell size, and cell density varies with variation of blowing agent and filler loading. Physical properties similar to relative density, hardness, tensile strength, elongation at break, modulus, and tear strength decreases with blowing agent concentration. The elastic nature of closed cells reduces the hysteresis loss compared to solid compounds. Set properties improve with blowing agent concentration. It is observed that stress relaxation behavior is independent of blowing agent loading (i.e., density of closed cell microcellular vulcanizates). Theoretically, flaw sizes are found to be about 3.08 times larger than maximum cell sizes observed from SEM photomicrographs. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 357–366, 2002
Thermal properties and crystalline structure of liquid crystalline poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate)
Authors: Rhee Do Mook , Ha Wan Shik , Youk Ji Ho , Yoo Dong Il 
Published: August 2002

AbstractThermal properties and crystalline structure of liquid crystalline (LC) poly(ethylene terephthalate‐co‐2(3)‐chloro‐1,4‐phenylene terephthalate) [copoly(ET/CPT)] were investigated using differential scanning calorimetry (DSC), thermogravimetry (TGA), limiting oxygen index (LOI) measurement, electron dispersive X‐ray analysis (EDX), X‐ray diffractometry, and infrared spectrometry (IR). The thermal transition temperatures of copoly(ET/CPT) were changed with the composition. Copoly(ET/CPT) showed two thermal decomposition steps and the residues at 700°C and LOI values of copoly(ET/CPT) were almost proportional to its chlorine content. The activation energy of thermal decomposition of LC units was very low compared to that of poly(ethylene terephthalate)(PET) units. Crystal structure of copoly(ET/CPT) (20/80) was of triclinic system with the lattice constants of a = 9.98 A˚, b = 8.78 A˚, c = 12.93 A˚, α = 97.4°, β = 96.1°, and γ = 90.8°, which is very close to that of poly(chloro‐p‐phenylene terephthlate) (PCPT) with the lattice constants of a = 9.51 A˚, b = 8.61 A˚, c = 12.73 A˚, α = 96.8°, β = 95.4°, and γ = 90.8°. When copoly(ET/CPT)(50/50) was annealed at 220°C in vacuum, crystallization induced sequential reordering (CISR) was not observed but the heat of fusion was slightly increased due to the increase of the trans isomer content in PET units. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1286–1294, 2002; DOI 10.1002/app.10451
Atomic force microscopy study of rubbed polyimide films
Authors: Devlin C. L. H. , Glab S. D. , Chiang S. , Russell T. P. 
Published: August 2002

AbstractThe surface of rubbed polyimide films was studied as a function of the film thickness and applied load using atomic force microscopy (AFM). Three dominant consequences of rubbing on the film topography were observed: scratches confined to the near surface of the film, tears that extended to the substrate, and strings of islands or droplets aligned parallel to the rubbing direction. Tears, found only in films less than 50 nm thick, varied in areal density and shape due to variations in the film thickness, rubbing load, and adhesion to the substrate. Strings of droplets aligned in the rubbing direction were seen on most samples without discernible dependence on the thickness or rubbing load. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1470–1477, 2001
Structural analysis of oriented poly(ε‐caprolactone) including CaCO3 particles with 13C solid‐state NMR
Authors: Ito Takuro , Yamaguchi Yuji , Watanabe Hiroto , Asakura Tetuso 
Published: August 2002

AbstractThe results of a study of the relation between the oriented structure and drawn Poly(ε‐caprolactone) specimens including CaCO3 particles and their dynamic mechanical properties are presented. The loss elasticity, E″, showed almost the same curve for both undrawn sheets and drawn sheets as a function of CaCO3 content. On the other hand, the storage modulus, E′, of drawn sheets increased nonlinearly with increasing CaCO3 content, and their curve showed lower E′ values than those of undrawn sheets. By simulation of 13C CP NMR spectra of drawn PCL/CaCO3 sheets, both oriented and unoriented components were observed. The distribution parameter, p, of drawn PCL/CaCO3 sheets was 13°, which was larger than those (8°) of drawn PCL. Further, the fraction of the unoriented component increased with increasing CaCO3 content. Thus, adding CaCO3 particles into the PCL, the arrangement of the oriented component was disturbed and decreased. In addition, from the line shape analyses of 13C CP MAS NMR spectra, four peaks were obtained in not only undrawn sheets but also in drawn sheets of both PCL and PCL/CaCO3 compounds. Besides, structural change occurred at only drawn PCL/CaCO3 sheets. Therefore, the change in dynamic mechanical properties observed only for drawn PCL/CaCO3 sheets were strongly dependent on the orientational structure, which was formed under shear stress of the stretching drawn process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2376–2382, 2001
Characterization of poly(dimethylsiloxane)‐poly(methyl hydrogen siloxane) composite membranes for organic water pervaporation separation
Authors: Osorio‐Galindo Marta , Iborra‐Clar Alicia , Alcaina‐Miranda Isabel , Ribes‐Greus Amparo 
Published: August 2002

AbstractHydrophobic composite membranes with a crosslinked poly(dimethylsiloxane)‐poly(methyl hydrogen siloxane) selective layer were prepared by using a new laboratory made catalyst agent. The pervaporation separation of five organic solvent–water mixtures was carried out with these composite membranes, together with swelling experiments in the same feed mixtures. The volatile organic compounds employed were ethanol, methanol, 1‐butanol, acetone, and ethyl acetate. The pervaporation and swelling experiments revealed that both the 1‐butanol and the ethyl acetate solutions showed the highest affinity for the composite membrane. When these components were employed as feed solutions, the membranes showed both high selectivity and high permeation. Mechanical–dynamical experiments of swollen and nonswollen composite membranes were also performed. The relaxation spectra were analyzed in terms of the interaction of the components of the different mixtures with the composite membrane, and the free volume corresponding to the each sample was obtained. Once the membranes had reached an equilibrium swelling, a decrease in the free volume was observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 546–556, 2001
Storage modulus of polybutadiene core in acrylonitrile–butadiene–styrene polymers with different degrees of grafting
Authors: Choi Joong‐Hwan , Ryu Jong‐Hoon , Kim Sang Yong 
Published: August 2002

AbstractThe linear viscoelastic behavior of acrylonitrile‐butadiene‐styrene (ABS) polymers in the molten state, with different degrees of grafting, was investigated within the framework of Palierne's emulsion model. The main aim of the present study is to quantitatively analyze the effect of grafting degree on the storage modulus G′ of the polybutadiene (PB) rubber core dispersed in ABS polymers. According to our model calculations, the degree of grafting significantly affects the G′ values of the PB core and, hence, the viscoelastic properties of ABS polymers. Our calculations showed that the Palierne model is very useful to calculate the storage modulus of the rubber particles dispersed in rubber‐modified polymeric materials, at least in the high‐frequency region. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 924–930, 2001
Synthesis and characterization of a copolymer: Poly(aniline‐co‐fluoroaniline)
Authors: Sharma Amit L. , Saxena Vibha , Annapoorni S. , Malhotra B. D. 
Published: August 2002

AbstractIn the present article, we report the chemical synthesis and characterization of poly(aniline‐co‐fluoroaniline) [poly(An‐FAn)]. The copolymerization of aniline and 2‐fluoroaniline was carried out by chemical method in acidic medium. The characterization of poly(aniline‐co‐fluoroaniline) was done using FTIR, UV‐visible spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron micrography (SEM), and a four‐points‐probe conductivity method. X‐ray diffraction (XRD) and SEM characterization reveal crystalline nature of doped copolymer compared to undoped copolymer. The observed decrease in the conductivity of the copolymer relative to polyaniline is attributed to the incorporation of the fluoro moieties into the polyaniline chain. The chemically synthesized copolymer shows good solubility in common organic solvents, and is, therefore, technological useful. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1460–1466, 2001
Drug‐releasing kinetics of MPEG/PLLA block copolymer micelles with different PLLA block lengths
Authors: Kim Sung Yeon , Kim Jee Heung , Kim Dukjoon , An Jung Ho , Lee Doo Sung , Kim Sung Chul 
Published: August 2002

AbstractCopolymers of poly(L‐lactic acid) and methoxy end‐capped poly(ethylene glycol) were synthesized, and their structure and physical properties were characterized. Micellar structures were formed in aqueous media because of the amphiphilic nature of the copolymers, and their sizes were measured with both dynamic light scattering equipment and scanning electron microscopy. Indomethacin was loaded into the copolymer micelles, and its releasing behavior was monitored. The drug‐releasing mechanism was determined from an investigation of the biodegradation kinetics of the copolymer micelles. The releasing mechanism was governed by diffusion rather than a biodegradation process. We adapted a model based on Fick's diffusion theory to describe the overall releasing behavior with the extraction of the diffusion coefficient. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2599–2605, 2001