bluuebunny/crossref_metadata_2025 huggingface dataset:
RE: Mesothelioma and lung tumors attributable to asbestos among petroleum workers. Am. J. Ind. Med. 2000. 37:275–282*
Authors: Ludwig Erich R. , Madeksho Larry , Egilman David
Published: September 2002

Gennaro et al. [2000] report that the latest installment in a series of articles on the effects of asbestos in petroleum refinery workers.

Over the past several years, there has been considerable controversy over potential increases in cancer rates in chemical and petroleum refinery workers. Many readers may be curious about the extent and vigor of the debate surrounding potential cancer increases in this small group of workers. Although this debate may seem like a tempest in a teapot, the policy implications that underlie this dispute are momentous.
Predictors of hearing loss in New York farmers
Authors: Hwang Syni‐An , Gomez Marta I. , Sobotova Lubica , Stark Alice D. , May John J. , Hallman Eric M.
Published: September 2002

Background

Data from the telephone interview portion of the New York Farm Family Health and Hazard Surveillance were used to study self‐reported hearing loss in New York farmers.

Methods

One thousand six hundred and twenty‐two persons completed the hearing loss and noise exposure interview. Hearing loss was defined as at least some trouble hearing in one or both ears. Predictors of hearing loss were determined using logistic regression.

Results

Twenty‐two percent of participants reported hearing loss. From the logistic regression, significant confounders are age (P = 0.0001), gender (P = 0.0001), being from a livestock farm (P = 0.012), and loss of consciousness due to head trauma (P = 0.04). Significant noise exposures are more hours of lifetime exposure to noisy farm equipment (P = 0.001) and having had a noisy non‐farm job (with some hearing protection P = 0.002, without any hearing protection P = 0.0001).

Conclusions

Farm noise exposure is a serious risk to the hearing of this population. Although use of hearing protection should be encouraged, replacing and modifying farm equipment to decrease noise at the source should be the first priority. Am. J. Ind. Med. 40:23–31, 2001. © 2001 Wiley‐Liss, Inc.
Accelerated silicosis in workers exposed to agate dust in Guangzhou, China*
Authors: Jiang C.Q. , Xiao L.W. , Lam T.H. , Xie N.W. , Zhu C.Q.
Published: September 2002

Background

An investigation of a small private agate mill was prompted by an agate worker who presented with silicosis in Guangzhou, China, in December 1998.

Methods

The work processes and records of dust measurements of the mill were examined. The mean total dust concentrations ranged from 3.0 to 9.9 mg/m3; 86–88% of the particles' diameter was smaller than 5.0 μm. Free SiO2 content from agate samples was measured. Occupational history was obtained and X‐ray chest and lung function was carried out.

Results

Free SiO2 content of the agate was 90.5%. Thirty‐two men involved in processing agate stone were examined. The mean ( ± SD) age was 29.8 ( ± 4.9) years and the mean (± SD) duration of exposure was 3.5 (± 1.7) years. Fifteen cases (47%) were diagnosed as accelerated silicosis. Up to September 1999, three had died from respiratory failure and five were in critical condition.

Conclusions

Silicosis is an important problem in primitive work environments. Am. J. Ind. Med. 40:87–91, 2001. © 2001 Wiley‐Liss, Inc.
Apportionment of global human genetic diversity based on craniometrics and skin color
Authors: Relethford John H.
Published: September 2002

A number of analyses of classical genetic markers and DNA polymorphisms have shown that the majority of human genetic diversity exists within local populations (≈85%), with much less among local populations (≈5%) or between major geographic regions or “races” (≈10%). Previous analysis of craniometric variation (Relethford [1994] Am J Phys Anthropol 95:53–62) found that between 11–14% of global diversity exists among geographic regions, with the remaining diversity existing within regions. The methods used in this earlier paper are extended to a hierarchical partitioning of genetic diversity in quantitative traits, allowing for assessment of diversity among regions, among local populations within regions, and within local populations. These methods are applied to global data on craniometric variation (57 traits) and skin color. Multivariate analysis of craniometric variation shows results similar to those obtained from genetic markers and DNA polymorphisms: roughly 13% of the total diversity is among regions, 6% among local populations within regions, and 81% within local populations. This distribution is concordant with neutral genetic markers. Skin color shows the opposite pattern, with 88% of total variation among regions, 3% among local populations within regions, and 9% within local populations, a pattern shaped by natural selection. The apportionment of genetic diversity in skin color is atypical, and cannot be used for purposes of classification. If racial groups are based on skin color, it appears unlikely that other genetic and quantitative traits will show the same patterns of variation. Am J Phys Anthropol 118:393–398, 2002. © 2002 Wiley‐Liss, Inc.
Brief communication: How much larger is the relative volume of area 10 of the prefrontal cortex in humans?
Authors: Holloway Ralph L.
Published: September 2002

It has long been thought that the prefrontal cerebral cortex has been greatly expanded in the human brain. Semendeferi et al. ([2001] Am. J. Phys. Anthropol. 114:224–241) showed that Brodmann's area 10 is relatively larger in the human compared to pongid brains. The question is: how much larger relatively is it? Using their data, it can be shown that the relative increase for human prefrontal area 10 is only 6% larger. Looking at the data base of neural structures provided by Stephan et al. ([1981] Folia Primatol. (Basel) 35:1–29), it is apparent that 6% is a relatively low residual value from a predicted value based on allometric considerations between total brain weight and any given neural structure. When this small increase is combined with their earlier findings on area 13 of prefrontal cortex (Semendeferi et al. [1997] J. Hum. Evol. 32:375–388), it appears that the prefrontal cortex in humans is not some 200% larger as claimed by some researchers (Deacon [1997] Symbolic Species, New York: W.W. Norton; cf. Holloway [1998] Am Sci 86:184–186), and that the findings of Semendeferi et al. ([2001] Am. J. Phys. Anthropol. 114:224–241) are in agreement with the earlier work (Semendeferi and Damasio [2000] J. Hum. Evol. 38:317–332; Semendeferi et al. [1997] J. Hum. Evol. 32:375–388), showing that the human frontal lobe volume is what would be expected for a primate of its brain size. While the prefrontal cortex may have increased relatively in Homo sapiens, the increase is likely to have been far less than currently believed. Am J Phys Anthropol 118:399–401, 2002. © 2002 Wiley‐Liss, Inc.
Late Pleistocene human femoral diaphyseal curvature
Authors: Shackelford Laura L. , Trinkaus Erik
Published: September 2002

Anterior femoral curvature is a consistent characteristic of Pleistocene and recent humans, although variation exists in the degree of curvature among individuals and across populations. In particular, one group, the Neandertals, has been characterized for a century as having marked femoral curvature. To evaluate the degree of anterior femoral curvature in both Neandertals and other Late Pleistocene humans, their curvature subtenses and proximodistal positions were evaluated in the context of recent human variation. Recent human comparisons show little relationship between subtense (absolute curvature) and femoral length, suggesting that an index that incorporates subtense relative to the length of the femur is inappropriate for between‐group assessments. Neandertals were statistically indistinguishable from Middle or earlier Upper Paleolithic modern humans in the degree of absolute curvature, all of whom had greater curvature on average than all later humans. Additionally, Neandertals and Qafzeh‐Skhul early modern humans had a more distal point of maximum curvature than any other group. Curvature was not strongly correlated with functional considerations including body mass estimates, surrogate variables for body size, proximal femoral articular orientation, or knee anteroposterior dimensions. The functional role of femoral anterior curvature is unknown; however, the general decrease in curvature subtense closely parallels the between‐group changes in inferred levels of mobility from femoral diaphyseal robusticity and shape, suggesting that femoral curvature may reflect mobility levels and patterns among Late Pleistocene and recent humans. Am J Phys Anthropol 118:359–370, 2002. © 2002 Wiley‐Liss, Inc.
Scoring system for estimating age in the foot skeleton
Authors: Whitaker Jeffrey M. , Rousseau Leslie , Williams Trevor , Rowan Reed A. , Hartwig Walter Carl
Published: September 2002

This study assesses chronological age of immature individuals from the degree of ossification evident in the foot skeleton. We considered all tarsal and ray bones in various combinations to determine the most sensitive indicators of chronological age. Skeletal maturity was rated according to a subjective but simple scoring system applied to radiographs of normal feet of children of known chronological age. Scales for assessing the primary center of ossification, secondary center of ossification, and state of fusion are defined. In general, as expected, females show earlier onset of skeletal maturity than males; in particular, females in our sample are skeletally mature in most elements beginning 48 months prior to the earliest incidence of skeletal maturity in males for the same bones. Females in our sample show a marked tendency toward skeletal maturity of all elements by 150 months of age, while males do not show the same tendency until approximately 200 months of age. In general within each sex, consecutive states of fusion show broad overlap in range of chronological age within each bone. Combining scores from several different bones enables a reasonable estimate of potential age in a test application of the model. Am J Phys Anthropol 118:385–392, 2002. © 2002 Wiley‐Liss, Inc.
Addition of Me3SiCN to trifluoromethyl derivates of N‐(pyridylmethylidene) anilines catalyzed by Lewis acids
Authors: Iovel Irina , Golomba Lena , Belyakov Sergey , Kemme Andrejs , Lukevics Edmunds
Published: September 2002

A series of novel Shiff bases (1a–h) was synthesized by condensation of pyridinecarboxaldehydes (1–4) with 3‐ and 4‐trifluoromethylanilines (5, 6) in the presence of molecular sieves (4 Å). It was found that AlCl3 and AlBr3 catalyzed the addition of Me3SiCN to the CN bond of the imines obtained, whereas the other Lewis acids studied (YCl3, LaCl3, ZnI2) were not active. The reactivity of the imines in the title reaction, on the whole, correlated with their basicity. Besides the addition giving the expected α‐amino nitriles (2a,b,d–f,h), an unusual reaction leading to unsaturated nitriles (3a–h) was observed. The structures of saturated and unsaturated products 2d and 3c were determined by X‐ray diffraction. Copyright © 2001 John Wiley & Sons, Ltd.
Degradation of triphenyltin compounds in sea water by pyoverdins from Pseudomonas chlororaphis
Authors: Yamaoka Yukiho , Inoue Hiroyuki , Takimura Osamu , Oota Sinji
Published: September 2002

The yellow compound species pyoverdin was isolated from Pseudomonas chlororaphis. Degradation of triphenyltin (TPT) by pyoverdin (20 mg) was carried in distilled water (30 ml) containing a 6 µg l−1 concentration of TPT at 20 °C for 96 h in aerobic conditions. The organotins in water and sea water were analyzed by gas chromatograph–mass spectrometry in selected ion mode. TPT and diphenyltin (DPT) in sea water were degraded to monophenyltin (MPT) with pyoverdins isolated from P. ­chlororaphis. Degradation of TPT in sea water increased with increasing temperature between 4 and 37 °C. Optimum degradation of TPT in sea water was at pH 7–8.5. Degradation of TPT and DPT in distilled water can be faster than in sea water. Also, degradation of TPT in both water and sea water was faster than that of DPT. Tributyltin, dibutyltin, monobutyltin and MPT in water and sea water were not degraded by pyoverdins isolated from P. chlororaphis. Copyright © 2001 John Wiley & Sons, Ltd.
Maternal transfer of arsenic to eggs of black‐tailed gull (Larus crassirostris) from Rishiri Island, Japan
Authors: Kubota Reiji , Kunito Takashi , Tanabe Shinsuke , Ogi Haruo , Shibata Yasuyuki
Published: September 2002

Concentrations of total arsenic and individual arsenic compounds were determined in several tissues and eggs of the black‐tailed gull (Larus crassirostris) to characterize accumulation and maternal transfer to eggs. A relatively high concentration of arsenic was observed in the liver, kidney, pancreas, muscle and gonad. The transfer rate of arsenic to eggs of the black‐tailed gull was about 10%. Chemical speciation analysis revealed that arsenobetaine was the major arsenic compound in all the tissues. Dimethylarsinic acid, methylarsonic acid, arsenocholine, and an unidentified arsenic compound were also detected as minor constituents. Like maternal tissues, egg also contained arsenobetaine as the major arsenic compound and dimethylarsinic acid as a minor compound. These results suggest that arsenobetaine and dimethylarsinic acid can transfer from the mother bird to the eggs. To our knowledge, this is the first report on the maternal transfer of arsenic species to eggs of seabirds. Copyright © 2002 John Wiley & Sons, Ltd.
Dimethylarsinic acid causes inhibition of microtubule assembly and inhibition of calcium‐sensitive disassembly of microtubules via interaction with glutathione
Authors: Ochi Takafumi , Meguro Shiori , Namikoshi Michio , Oya‐Ohta Yukiko , Kaise Tosikazu
Published: September 2002

The effects of dimethylarsinic acid (DMAA) on microtubule assembly in vitro were investigated in terms of the role of glutathione (GSH). Increase in turbidity due to assembly of brain tubulins was monitored in the presence or absence of DMAA. DMAA at concentrations up to 10 mM did not cause inhibition of the increased turbidity. GSH at concentrations over 10 mM enhanced the increase in turbidity. By contrast, the increased turbidity was inhibited markedly when DMAA and GSH were combined in the ratio of 5:1. Moreover, the combination similarly inhibited calcium‐induced disassembly of microtubules with a potency equivalent to that of 10 µM taxol. These results suggest that DMAA inhibited not only microtubule assembly, but also calcium‐sensitive disassembly of microtubules, via interaction with GSH. Copyright © 2002 John Wiley & Sons, Ltd.
Short Communucation: An arsenosugar as the major extractable arsenical in the earthworm Lumbricus terrestris
Authors: Geiszinger Anita E. , Goessler Walter , Kosmus Walter
Published: September 2002

Earthworms (Lumbricus terrestris) were investigated for arsenic compounds by high‐performance liquid chromatography inductively coupled plasma mass spectrometry MS. Total arsenic concentrations were 6.3 ± 0.4 mg kg−1 in the earthworms and 28.1 ± 1.9 mg kg−1 in the casts of the earthworms. Extraction of the samples removed ∼25% of total arsenic from the earthworm tissues, but only ∼0.7% from the casts. The major arsenic compound in the earthworm extracts was an arsenic‐containing carbohydrate (phosphate arsenosugar, ∼55%); glycerol arsenosugar, dimethylarsinic acid, methylarsonic acid, arsenate, and arsenite were also present as minor constituents. In the cast extracts, the two arsenosugars could also be detected in addition to some arsenate and arsenite. The identification of the phosphate arsenosugar was confirmed with liquid chromatography– electrospray‐mass spectrometry with detection of m/z 75 (As+) and m/z 483 [(M + H)]+; the data were identical with those recorded for authentic standard material. This is the first report of an arsenosugar as the major extractable arsenical in a terrestrial animal. Copyright © 2002 John Wiley & Sons, Ltd.
Utilization of some oligomers based on poly(ethylene terephthalate) wastes as modifiers for polyvinyl chloride
Authors: Mansour S. H. , Abd‐El‐Messieh S. L. , Ikladious N. E.
Published: September 2002

Two glycolyzed products, PET‐TEG and PET‐BD, were prepared by depolymerization of PET wastes using 30 wt % triethylene glycol (TEG) and 40 wt % 1,4‐butanediol (BD). In this work we investigated how the mechanical and electrical properties of PVC and PVC/EPDM blend were affected by mixing them with different concentrations of the two obtained glycolyzed products. Dynamic mechanical, DSC, and dielectric behaviors of PVC containing various amounts of the two modifiers were studied. The present data confirm that the α‐relaxation dynamic of PVC at constant frequency shifts to a lower temperature with increasing modifier content. PVC samples containing 5 phr of the two modifiers show the highest impact strength at −30°C. It was noted that addition of PET‐TEG to PVC or PVC/EPDM blend led to end products with enhanced insulating properties, which makes them suitable for industrial applications. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2501–2509, 2002
Robust on‐line measurement of conversion and molecular weight using NIR spectroscopy during solution polymerization
Authors: Cherfi A. , Fevotte G. , Novat C.
Published: September 2002

Fiber‐optic near‐infrared (NIR) spectroscopy was used to monitor the monomer conversion and the weight‐average molecular weight of the polymer produced during solution polymerization of methyl methacrylate (MMA) carried out in a lab‐scale reactor. NIR spectra were recorded during batch and semi‐continuous reactions using an in situ transmission probe. Off‐line gravimetry and GPC were used as reference methods to provide the conversion and the average molecular weight data set required for the calibration procedure. A statistical model was generated using partial least‐squares regression (PLS) to relate the NIR spectral data to the two polymerization variables of interest. The measurements were then validated for various operating conditions (i.e., different solvent, initiator, MMA, and chain‐transfer agent concentrations) and for both batch and semi‐continuous modes. The conversion was predicted during three validation experiments with an average standard error of prediction (SEP) of 2.1%. The on‐line evaluation of M̄w was obtained with an average relative SEP of 5.7%; such on‐line NIR measurement was thus demonstrated to be robust and accurate, even in the case of versatile use of the polymerization plant. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2510–2520, 2002
Acrylonitrile–maleic anhydride copolymer membranes with different molecular weights
Authors: Pei Zhi‐Chao , Pei Yu‐Xin , Wang Qing‐Rui
Published: September 2002

The structure and performance of acrylonitrile–maleic anhydride copolymer membranes with different molecular weights were investigated. The results showed that the water flux of the membrane decreased gradually with increasing molecular weight of the copolymer; the rejection increased only when there was an obvious increase of molecular weight. The addition of an additive (polyvinylpyrrolidone) largely decreased the water flux and rejection of the membrane when the concentration of the copolymer remained unchanged. The higher the molecular weight, the thicker were the transition layer and the wall of the support pore and the better was the anticompactness of the membrane. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2521–2527, 2002
Interaction between unlike macromolecules: A new method based on the motional resistance response of a piezoelectric quartz crystal
Authors: Mao Youan , Wei Wanzhi , Zhang Jinzhong
Published: September 2002

A new method for the study of the interaction between unlike macromolecules was developed, based on the motional resistance (Rm) response of a piezoelectric quartz crystal sensor to viscosity change in a contacting dilute polymer solution. The experimental setup, constructed with a 9‐MHz AT‐cut quartz crystal, a flowthrough detection cell, and an impedance analyzer, was shown to provide highly reproducible data at 25°C and a fluid flow rate of 1.3–1.6 mL/min. A quantitative relationship between Rm and the relative viscosity of the dilute polymer solution was derived. A model for using Rm to study the interaction was proposed. The interaction between polyethylene glycol (PEG) and poly(vinyl alcohol) (PVAL) was studied by this method with a thermodynamic parameter α. Experimental results indicated that the values of α for the blend PEG/PVAL were 0.094 and 0.086, corresponding to molecular weights of PEG of 10,000 and 20,000, respectively, and in agreement with those of capillary viscometry. The positive value of α showed that an attractive interaction existed between PEG and PVAL. An important feature of the new method was that it could be used in continuous measurement. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2528–2534, 2002
Thermal degradation of cellulose‐based complex material
Authors: Ou Yifang , Huang Qiulian
Published: September 2002

Thermal degradation of cellulose‐based complex material was investigated by treating at 100, 140, and 160°C, respectively. The performance changes of the material such as average degree of polymerization (DP), weight loss, brightness, and tensile strength were tested during the thermal treatment. And the thermal analyses of the material was conducted to show the change in different heating stage from 27 to 700°C. The effect of anti water and anti oil agents in the complex material on the change of performances was investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2535–2539, 2002
Synthesis and characterization of novel magnetic polymer microspheres with photoconductivity
Authors: Zhang Junhua , Ding Xiaobin , Peng Yuxing , Wang Mang
Published: September 2002

Functional Fe(III)‐phthalocyanine with vinyl groups was synthesized, and the structure was confirmed using Fourier transform infrared spectroscopy and elemental analysis, separately. A novel magnetic polymer microsphere with photoconductivity was prepared by copolymerization of styrene and functional Fe(III)‐phthalocyanine, which was used as a comonomer, in the presence of Fe3O4 magnetic fluid. The structure and morphology of magnetic polymer microspheres were determined by infrared analysis, elemental analysis, thermogravimetric analysis, and scanning electron microscopy. The magnetic responsiveness and photoconductivity were studied. The average size of the microspheres was 38.1 μ, with multidistribution. The microsphere has a good magnetic responsiveness and a good photoconductivity at 762.5 nm. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2609–2614, 2002
Rheological behavior of styrene‐maleic anhydride/polyol blends obtained through reactive processing
Authors: Bayram G. , Yilmazer U. , Xanthos M. , Patel S. H.
Published: September 2002

The condensation reaction of styrene‐maleic anhydride copolymer (SMAH) with polytetramethylene ether glycol (PTMEG) in the presence or absence of a hydrated zinc acetate catalyst was studied in a batch mixer. As a control, pure SMAH and an SMAH/catalyst blend were also subjected to the same processing conditions. The reaction characteristics of the blends were investigated by Fourier transform infrared spectroscopy (FTIR) and thermal and rheological analysis. FTIR analysis of the SMAH/PTMEG blend indicated ester formation. The addition of zinc acetate and/or PTMEG to SMAH decreased the glass transition temperature of pure SMAH. Oscillatory shear properties of storage modulus, G′, loss modulus, G″, and complex viscosity, η*, were measured. The SMAH/PTMEG/zinc acetate blend had higher G′, G″, and η* than the blend without the zinc acetate catalyst. The parameters of the relaxation spectra were calculated by using the experimental oscillatory data and the generalized Maxwell model. Zero shear viscosity and the mean relaxation time increased with addition of zinc acetate and/or PTMEG to SMAH as a result of chain extension/branching reactions. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2615–2623, 2002
Grafting and quaternization of 2‐(dimethylamino)ethyl methacrylate onto polyamide‐6 fabric pretreated with acetone
Authors: Ramadan A. M. , Mosleh S. , Gawish S. M.
Published: September 2002

Grafting of polyamide (PA‐6) pretreated with acetone was done using 2‐(dimethylamino)ethyl methacrylate (DMAEM). It was found that the percentage graft yield of acetone‐pretreated PA fabric was higher than the untreated and there was a difference of 4% under the same conditions. The graft yield was studied as a function of the different variable conditions such as monomer concentration, reaction time, and temperature. The pretreated and grafted DMAEM‐PA fabric was then quaternized with different alkylating agents including ethyl iodide, benzyl chloride, and epichlorohydrin. The grafted and quaternized fabrics had a significant increase in dyeability. The quaternized fabric showed higher moisture regain compared to the ungrafted one and that could enhance the antistatic effect of such fibers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2318–2323, 2001
A novel and efficient xanthenic dye–organometallic ion‐pair complex for photoinitiating polymerization
Authors: Grotzinger C. , Burget D. , Jacques P. , Fouassier J. P.
Published: September 2002

The photochemistry of the complex formed between a Rose Bengal dianion (RB) and a ferrocenium salt [Fc(+)] is described in this article. Stoichiometric analysis of the crystal showed that the Fc(+):RB ratio is 2:1. The dissociation percentage of complex RB(Fc)2 in several solvents was evaluated using fluorescence studies. In nonpolar media, in which most of the RB(Fc)2 exists as contact ion pairs, the photodegradation rate of the complex was found to be unaffected by the presence of oxygen and led to photoproducts capable of initiating a radical polymerization reaction. Because of this, the initiation step showed low oxygen inhibition. In fact, in a visible‐light photoinitiating system such as one composed of xanthene dye (Rose Bengal), ferrocenium salt, amine, and hydroperoxide, substituting the complex RB(Fc)2 for the sensitizing dye RB led to an increase in efficiency of the polymerization (especially under aerated conditions) as compared to that obtained in the presence of benzoyl phosphine oxide derivatives. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2368–2376, 2001
Electrooptical‐responsive microsphere with ferroelectric liquid crystalline segments
Authors: Yoshida Masahiro , Fan Xinghe , Uemura Yoshimitsu , Hatate Yasuo
Published: September 2002

We synthesized a ferroelectric liquid crystalline monomer (4‐[4′‐(7‐octeneloxy)benzoyloxy]benzoate‐2‐methylbutyester, OBBM) possessing both carboxyl p‐benzolxybenzoate and carboxyl (s)‐(‐)‐2‐methylbutylester as a mesogenic group in its side chain. The liquid crystalline and styrene monomers were employed to make matrices of microspheres prepared by dispersion, suspension, or emulsion polymerization. In this study, we investigated, in detail, physicochemical properties, thermal responses, and electrooptical responses of the microspheres possessing liquid crystalline abilities. The ferroelectric liquid crystalline monomer OBBM had a thermotropic liquid crystalline ability, two‐phase transition temperatures, and a Smectic C* texture, which is characteristic of ferroelectric liquid crystalline substances. The microspheres prepared also exhibited a liquid crystalline ability, and the phase‐transition temperatures toward the liquid crystalline segments into the microspheres prepared by copolymerizing the liquid crystalline and styrene monomers could be decreased with increasing of the styrene monomer. Furthermore, we found that the microspheres remarkably exhibited electrooptical responses at about 8 V. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2490–2499, 2001
Blends of polyamide 6, polycarbonate, and poly(propylene oxide). II. Reactive compatibilization–thermal degradation relationships
Authors: Costa Dilma A. , Oliveira Clara Marize F.
Published: September 2002

The thermal degradation of some blends of polyamide 6/polycarbonate (PA6/PC) and polyamide 6/polycarbonate/poly(propylene oxide) (PA6/PC/PPO) were investigated. The copolymer formed during the mixing of polyamide 6 and polycarbonate, at 240°C, for 30 min, increases the thermal stability of PA6/PC and of PA6/PC/PPO blends. This increase in the thermal stability occurs due to the plasticizing effect of PPO, which increases the mobility of the molecules of PA6 and PC, and consequently increases the probability of the reaction between the —NH2 and —O—CO—O groups of polyamide 6 and polycarbonate, respectively. The ternary blends with PPO (5–10% w/w) have lower thermal stability than PA6/PC blends. This is due to the decrease of miscibility between these polymers and the rise of the diluting effect. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2556–2562, 2001
Crystallization of vulcanizates. I. Low‐temperature crystallization as a function of extent of cure for polyisoprene vulcanized with tetramethylthiuram disulfide/sulfur and 2‐bisbenzothiazole‐2,2′‐disulfide/sulfur
Authors: Van Der Merwe M. J. , Gradwell M. H. S. , McGill W. J.
Published: September 2002

The crystallization of polyisoprene, vulcanized to various degrees of cure with tetramethylthiuram disulfide/sulfur and 2‐bisbenzothiazole‐2,2′‐disulfide (MBTS)/sulfur formulations, was studied in a density column at −25°C. The densities of vulcanizates before crystallization decrease progressively with cure time, which is ascribed to an increase in free volume occasioned by the formation of accelerator‐terminated pendent groups on the polymer chain. The induction period before the onset of crystallization increases and both the rate of and the degree of crystallization decrease with extent of cure. This is attributed primarily to the presence of residual pendent groups on the polymer chain and secondly to crosslink formation. The changes are more marked with MBTS formulations where pendent groups are more bulky. MBTS compounds fail to crystallize once vulcanized to the point where a gel has formed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2565–2572, 2001
Crystallization of vulcanizates. II. Low‐temperature crystallization as a function of extent of cure for polybutadiene vulcanized with dicumyl peroxide, tetramethylthiuram disulfide, 2‐bisbenzothiazole‐2,2′‐disulfide, and zinc–accelerator complexes
Authors: Van Der Merwe M. J. , Gradwell M. H. S. , McGill W. J.
Published: September 2002

Polybutadiene compounds, vulcanized to various degrees of cure, were crystallized in a density column at −16°C. The percentage crystallinity of vulcanizates was also determined by differential scanning calorimetry where samples, precooled at a programmed rate, were reheated. Curing with peroxides has little effect on either the rate or the extent of crystallization, except at very high crosslink densities, although the induction period prior to crystallization increases progressively with increased crosslink density. Tetramethylthiuram disulfide (TMTD)/sulfur and 2‐bisbenzothiazole‐2,2′‐disulfide (MBTS)/sulfur vulcanizates, cured for progressively longer periods, were found to have lower densities, a result attributed to an increase in free volume occasioned by the formation of accelerator‐terminated pendent groups on the polymer chain. The induction period for crystallization increases and both the rate and the extent of crystallization decrease with extent of cure. These changes are more marked for MBTS vulcanizates that do not crystallize once a gel has formed. Formulations with zinc stearate develop higher crosslink densities and crystallize to a greater extent on cooling, showing the effect of zinc stearate in the crosslinking of pendent groups. The densities of both zinc dimethyldithiocarbamate [Zn2(dmtc)4]– and zinc mercaptobenzothiazole [Zn(mbt)2]–accelerated sulfur vulcanizates increase with cure time, a result attributed to the formation of ZnS in the compounds. Zn2(dmtc)4 compounds crystallize extensively on cooling, pointing to limited main‐chain modification. It is suggested that main‐chain modification in these vulcanizates may comprise cyclic sulfide formation. Zn(mbt)2 compounds crystallize less readily than Zn2(dmtc)4 compounds, but to a greater extent than MBTS/sulfur compounds. The crystallization of the vulcanizates is discussed in terms of vulcanization reactions that give rise to crosslinking with the different formulations used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2573–2586, 2001
Synthesis and swelling characteristics of poly(4‐vinylpyridine) gels crosslinked by irradiation
Authors: Acar Nermin
Published: September 2002

The effect of irradiation under vacuum on thermal properties and swelling behavior on poly(4‐vinylpyridine) (P4VP) was investigated. The gel percentage in the irradiated P4VP films was determined by Soxhlet extraction. UV spectroscopy was also used to determine sol percentage, which decreased as the radiation dose increased. The changes in thermal properties, such as glass‐transition temperature (Tg), were followed by differential scanning calorimetry before and after Soxhlet extraction. The gels prepared after irradiation were characterized with respect to their swelling properties and network structures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2609–2614, 2001
A new method for treatment of sol‐gel data in irradiated polymers
Authors: Shyichuk A. V. , Tokaryk G. V.
Published: September 2002

A log‐log plot of sol fraction versus dose has been found to be an effective graphical technique to treat sol‐gel analysis data. The treatment procedure is described in detail with an example of radiation crosslinking of linear low‐density polyethylene. Radiation chemical yields both for crosslinking and scission of macromolecules were determined using Monte Carlo simulation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2621–2625, 2001
Cellulose furoate. I. Synthesis in homogeneous and heterogeneous systems
Authors: Hon David N.‐S. , Yan Hui
Published: September 2002

Cellulose furoate was synthesized via heterogeneous and homogeneous reactions. Cotton cellulose and wood cellulose were used. Lithium chloride/dimethylacetamide solvent was used to dissolve the cellulose for the homogeneous reaction. The esterification reaction between cellulose and 2‐furoyl chloride was systematically studied. It revealed that the activation of cellulose was important for its esterification reaction. Activation by solvent exchange decreased the crystallinity and increased the accessibility of cellulose. X‐ray diffraction analysis showed no significant change in the spectrogram after activation of cellulose. The degree of substitution of cellulose furoate was influenced by the molecular weight of the cellulose, the stoichiometry of the reagents, the acid scavenger, and the reaction time. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2649–2655, 2001
Properties and application of poly(acrylphenylamidrazone‐phenylhydrazide) chelating fiber for enrichment–separation of trace gold and ruthenium from solution samples
Authors: Chang Xijun , Yang Xiulan , Wang Bingtao
Published: September 2002

An ICP‐OES method using a new poly(acrylphenylamidrazone‐phenylhydrazide) chelating fiber to enrich and separate trace Au(III) and Ru(III) ions from solution samples is established. The results show that 50–500 ng/mL of Au or Ru ions can be enriched quantitatively by 0.1 g of the fiber at pH 4, with recoveries > 96%. The ions can be desorbed quantitatively with 10 mL of 4 M HCl and 3.0% CS(NH2)2 solution from the fiber column, with recoveries > 97%, and 200–1000‐fold excesses of Cu(II), Zn(II), Ca(II), Mg(II), Mn(II), Cr(III), Fe(III), Ba(II), and Al(III) caused little interference in the determination of these ions by ICP–OES. The chelating fiber can be reused eight times, and the recoveries are all > 95%. The relative standard deviations for enrichment and determination of 50 ng/mL of Au and Ru are in the range 1.8–1.9% (1.9% for Au and 1.8% for Ru). The recoveries of trace Au and Ru ions added to real waste water and alloy samples are 96–98%. The concentration of each ion found in the alloy samples was in good agreement with that provided by the plant. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2656–2660, 2001
Thermal properties and flame retardance of Al(OH)3/polypropylene composites modified by polypropylene grafting with acrylic acid
Authors: Mai Kancheng , Li Zhengjun , Qiu Yuxin , Zeng Hanmin
Published: September 2002

The effect of polypropylene grafting with acrylic acid, PP‐g‐AA (FPP), on crystallization and melting behavior, thermal degradation, and limiting oxygen index of Al(OH)3/PP composites were investigated. The results indicated that crystallization temperature of PP shifted to high temperature with increasing content of Al(OH)3 because of the interfacial heterogeneous nucleation of Al(OH)3 and further increased by the addition of FPP and with increasing FPP content because of the improvement of the dispersion of Al(OH)3 in PP matrix and the increase in the nucleating sites of Al(OH)3. With adding Al(OH)3 and increasing the content of Al(OH)3, limiting oxygen index values of composites increased and further improved by adding FPP. This is attributed to the presence of an interfacial interaction between FPP and Al(OH)3. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2679–2686, 2001
Immobilization of glucoamylase on the plain and on the spacer arm‐attached poly(HEMA‐EGDMA) microspheres
Authors: Arica M.Yakup , Yavuz Handan , Denizli Adil
Published: September 2002

Immobilization glucoamylase onto plain and a six‐carbon spacer arm (i.e., hexamethylene diamine, HMDA) attached poly(2‐hydroxyethylmethacrylate‐ethyleneglycol dimethacrylate) [poly(HEMA‐EGDMA] microspheres was studied. The microspheres were prepared by suspension polymerization and the spacer arm was attached covalently by the reaction of carbonyl groups of poly(HEMA‐EGDMA). Glucoamylase was then covalently immobilized either on the plain of microspheres via CNBr activation or on the spacer arm‐attached microspheres via CNBr activation and/or using carbodiimide (CDI) as a coupling agent. Incorporation of the spacer arm resulted an increase in the apparent activity of the immobilized enzyme with respect to enzyme immobilized on the plain of the microspheres. The activity yield of the immobilized glucoamylase on the spacer arm‐attached poly(HEMA‐EGDMA) microspheres was 63% for CDI coupling and 82% for CNBr coupling. This was 44% for the enzyme, which was immobilized on the plain of the unmodified poly(HEMA‐EGDMA) microspheres via CNBr coupling. The Km values for the immobilized glucoamylase preparations (on the spacer arm‐attached microspheres) via CDI coupling 0.9% dextrin (w/v) and CNBr coupling 0.6% dextrin (w/v) were higher than that of the free enzyme 0.2% dextrin (w/v).The temperature profiles were broader for both immobilized preparations than that of the free enzyme. The operational inactivation rate constants (kiop) of immobilized enzymes were found to be 1.42 × 10−5 min−1 for CNBr coupled and 3.23 × 10−5 min−1 for CDI coupled glucoamylase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2702–2710, 2001
Study of poly(ethylene oxide) electrolyte with polyurethane/sulfonate side chains
Authors: Wang Xinling , Fang Bin , Wang Lei , Tang Xiaozhen , Chang Feng‐Chih
Published: September 2002

Sulfonated dimethyl fumarate (SDMF) was prepared. Poly(ethylene oxide) (PEO) with sodium sulfonate side chains (SPEO) was synthesized by transesterification between SDMF and PEO with molecular weights of 200, 400, 600, 800, and 1000. The SPEO was subsequently mixed as a plasticizer with PEO polyurethane (PU). Samples were characterized by elemental analysis, FTIR, 1H‐NMR, gel permeation chromatography, and impedance analysis. The mixture exhibited a homogeneous domain. The maximum conductivity of the CPU1000/SPEO600 was 2.6 × 10−7 S cm−1 at room temperature. The relation between the ionic conductivity and the temperature was in agreement with the Arrhenius equation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 541–545, 2001
Isothermal crystallization and spherulite structure of partially miscible polypropylene–linear low‐density polyethylene blends
Authors: Li Jun , Shanks Robert A. , Long Yu
Published: September 2002

Polypropylene (PP) was blended with a linear low‐density polyethylene (LLDPE, containing 5% hexene comonomer) over a composition range of 10–90% of PP. The crystallization and morphology of the PP–LLDPE blends were studied by differential scanning calorimetry (DSC), polarized optical microscopy with a hot stage (HSOM), and scanning electron microscopy (SEM). In particular, the isothermal crystallization of PP in molten LLDPE was investigated. It was observed that the crystallization and melting behavior of PP and LLDPE changed in the blends, indicating that there was some degree of miscibility between the PP and the LLDPE. A depression of the equilibrium melting temperature (T) of PP in the blends with no more than 15% of PP confirmed that PP was miscible with LLDPE at and below 15% of PP. In addition, a drastic decrease in T from the 25% PP blend to the 20% blend led us to conclude that the miscible behavior between PP and LLDPE became favorable at a PP concentration of 20%. The optical microscopic images showed that, in the blends with 10 and 15% of PP, the PP crystallized as open‐armed diffuse spherulites, similar to those in the miscible blends. In contrast, the PP crystallized in a phase‐separated matrix or droplets with more than 25% of PP, when obvious phase separation occurred. The SEM image revealed that the PP lamella was able to penetrate the PP and LLDPE phase boundary and grow in the LLDPE phase. The above results displayed that the PP dissolved in the LLDPE, and, particularly, when the PP concentration was below 20%, the dissolution was substantial. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 628–639, 2001
Temporomandibular joint in miniature pigs: Anatomy, cell replication, and relation to loading
Authors: Herring Susan W. , Decker Jay D. , Liu Zi‐Jun , Ma Tsun
Published: September 2002

The mechanical environment is a regulator of growth and adaptation of the musculoskeletal system, including joints. Although pigs (Sus scrofa) are used frequently as models for temporomandibular joint (TMJ) dysfunction, no systematic description of microanatomy exists for this species. We injected the thymidine analog 5‐bromo‐2′‐deoxyuridine (BrdU) into 10‐ to 11‐month‐old miniature pigs that were undergoing measurements of TMJ bone strain. Ten hr later, the animals were sacrificed and their heads were perfused. Histological sections were used to map the distribution of replicating cells. Additional observations were made on gross dissections of jaw joints obtained from an abattoir. The pig TMJ is better supported than that of humans laterally and medially, but more vulnerable posteriorly. The posterior attachment area of the intra‐articular disc is fibro‐fatty rather than vascular, as in humans. Cartilage lines the articular eminence as well as the condylar surface. At the posterosuperior region of the condyle, the cartilage ends abruptly and is replaced by an invaginating, actively replicating periosteum. Almost all of the BrdU‐labeled cells resided in the prechondroblastic zones. The condyle had more replicating cells than did the eminence (P < 0.02), but lateral and medial locations did not differ in either element. In sagittal sections, the condyle had more replicating cells posteriorly (P < 0.001), but no A‐P differences were seen in the eminence. Comparisons of these data with data on bone strain indicate that increased loading is negatively associated with cell replication. Anat Rec 266:152–166, 2002. © 2002 Wiley‐Liss, Inc.
Experimental confirmation of the sheep model for studying the role of calcified fibrocartilage in hip fractures and tendon attachments
Authors: Shea Jill E. , Hallows Rhett K. , Bloebaum Roy D.
Published: September 2002

Research has shown that there is a dramatic increase in the fractional area of calcified fibrocartilage from tendon and capsular insertions on the human femoral neck (Vajda and Bloebaum, 1999; Shea et al., 2001b). Additional information regarding the properties of the proximal femur's cortical shell, gained from the use of an animal model, may result in a better understanding of elderly hip fracture since the cortical shell is a significant contributor to the strength of the proximal femur. The objective of the present study was to determine if the greater trochanter's tendon insertions of the human, rat, and sheep differ in terms of morphology and mineralization. The tendons of the greater trochanter of the human, rat, and sheep were observed to insert via a fibrocartilage insertion. The mineral content of the human and sheep calcified fibrocartilage was significantly higher than that of the rat calcified fibrocartilage (P < 0.01). Additionally, the mineral content of the rat cortical bone was significantly higher than that of the human cortical bone (P < 0.01). The mineral content of the calcified fibrocartilage and bone of the human and sheep were not statistically different from each other. There were also more similarities between the bone structure and lacunae density of the human and sheep than between the human and the rat. This suggests that the tendon insertions of the sheep are a better model than the tendon insertions of the rat for the investigation of calcified fibrocartilage in elderly hip fractures. Anat Rec 266:177–183, 2002. Published 2002 Wiley‐Liss, Inc.
Squamotympanic fissure in the Ngandong and Sambungmacan hominids: A reply to Delson et al.
Authors: Durband Arthur C.
Published: September 2002

In the present study the course of the squamotympanic fissure of the mandibular fossa is examined in several fossil hominid specimens. While previous work by several authors had found that the course of this fissure was potentially autapomorphic for the Ngandong and Sambungmacan fossil samples from Indonesia, a more recent study performed by Delson et al. (Anat Rec 2001; 262:380–397) reported that a number of other fossils, including OH 9, Sangiran 4 and 17, and KNM WT 15000 were similar to the Ngandong and Sambungmacan specimens in the expression of this feature. To test these findings, those specimens purported to share similarities with Ngandong and Sambungmacan were examined. The results of this study indicate clearly differing morphologies between the Ngandong and Sambungmacan fossils, on the one hand, and the four African and Indonesian fossils named by Delson et al. (2001). Hence, the course of the squamotympanic fissure remains a potentially autapomorphic feature separating the Ngandong and Sambungmacan samples from the remaining specimens allocated to Homo erectus. Anat Rec 266:138–141, 2002. © 2002 Wiley‐Liss, Inc.
Trust, but verify: The necessity of empirical verification in quantitative neurobiology
Authors: Farel Paul B.
Published: September 2002

The preferred procedure for estimating neuron number has been the subject of intense discussion. Sampling error, systematic bias, and the physical properties of the tissue examined all contribute to the possibility that estimates may not reflect actual neuron number. Even when restricting analysis to a particular, well‐defined structure such as dorsal root ganglia, these factors act in a manner that varies with maturity of the animal, species, fixation, processing, and neuron size. These considerations reinforce the necessity of comparing estimates with the actual number of neurons as determined by three‐dimensional reconstructions. Anat Rec (New Anat) 269:157–161, 2002. © 2002 Wiley‐Liss, Inc.