bluuebunny/crossref_metadata_2025 huggingface dataset:
Cellular location of proteins related to iron absorption and transport
Authors: Simovich Marcia J. , Conrad Marcel E. , Umbreit Jay N. , Moore Elizabeth G. , Hainsworth Lucille N. , Smith Hilary K.
Published: October 2004

K562 erythroleukemia cells and IEC6 rat cells were examined using confocal microscopy and antibodies raised against DMT‐1 (Nramp‐2, DCT‐1), transferrin receptor (CD71), β3 integrin (CD61), mobilferrin (calreticulin), and Hephaestin. The cellular location of each of these proteins was identified by immunofluorescence in both saponin‐permeabilized and non‐permeabilized cells. Fluorescent reactivity was observed on or near the cell surface of each of these proteins, suggesting that they might participate in surface membrane transport of iron. Fluorescence was observed in the region of the cytoplasm with each antibody to include β3 integrin and transferrin receptor. It was pronounced in cells incubated with mobilferrin, Hephaestin, and DMT‐1 antibodies. Speckled nuclear fluorescence was observed in cells incubated with anti‐DMT‐1. While these observations are descriptive, they demonstrate that there are significant concentrations of DMT‐1, mobilferrin, and Hephaestin in the cytoplasmic region of cells. This suggests that there may be intracellular roles for these proteins in addition to their serving to transit iron across the cell surface membrane. Am. J. Hematol. 69:164–170, 2002. © 2002 Wiley‐Liss, Inc.
Organophosphate pesticide residues in urine of farmworkers and their children in Fresno County, California
Authors: Mills Paul K. , Zahm Shelia Hoar
Published: October 2004

Background

Childhood cancer, notably leukemia, brain cancer, non‐Hodgkin's lymphoma, soft tissue sarcoma, and Hodgkin's disease, has been associated with pesticide exposure, often with greater relative risks than among exposed adults, suggesting greater susceptibility in children. These differences in risk may be due to developmental factors or differences in pesticide exposure.

Methods

A feasibility study was conducted to determine levels of pesticide metabolites in urine of adults (n = 18) and children (n = 9) in Fresno County, California, an intensely agricultural county in the Central San Joaquin Valley. Spot urine samples were obtained and analyzed for six metabolites of organophosphate (OP) pesticides using gas chromatography with flame photometric detection methods. The metabolites of OP pesticides included DMP, DEP, DMTP, DMDTP, DETP, and DEDTP.

Results

Levels were generally low for both adults and children for most metabolites tested. Frequencies of detection ranged from 0 to 37%, with mean levels ranging from non‐detectable to 13.22 ppb. However, levels of several metabolites were higher in children than in adults. The most frequently detected metabolite, DMP, was found among 44% of the children and 33% of the adults. DMTP was detected among 33% of the children and 28% of the adults.

Conclusions

These results are difficult to interpret given the sampling variation associated with the small sample size. Nevertheless, because OP pesticides have been associated with increased cancer risk in animal and human studies, these results indicate a need to closely monitor children's exposure to environmental chemicals. Am. J. Ind. Med. 40:571–577, 2001. © 2001 Wiley‐Liss, Inc.
Evaluation of Mexican American migrant farmworker work practices and organochlorine pesticide metabolites
Authors: Hernández‐Valero María A. , Bondy Melissa L. , Spitz Margaret R. , Zahm Shelia H.
Published: October 2004

Background

Epidemiologic studies often must rely upon questionnaire data to assess past exposures. The ability of questionnaires to rank migrant farmworkers according to past pesticide exposure is not known.

Methods

We conducted a pilot feasibility study to measure a panel of 21 organochlorine pesticides (OCPs) and correlate levels with reported occupational exposures in 26 Mexican–American migrant farmworkers in Baytown, Texas. The Migrant Farmworker Questionnaire developed by the National Cancer Institute (NCI) was administered and each participant donated a blood sample. Three OCPs [mean (ppb) levels: mirex 1.8, DDT 1.0, and trans‐nonachlor 0.7] were detected despite the fact that these chemicals have been banned in the US for many years, and the detected levels were far higher than the standard provided by the referent laboratory. Work clothes, protective attire, and self‐reported pesticide exposures were significant predictors of OCP exposure. Similarly, personal hygiene, length of employment, and number of duties also predicted OCP exposure.

Conclusions

The results of this study indicate that data obtained from standardized questionnaires may be reasonable indicators of occupational exposure when biomarker data are not available. Am. J. Ind. Med. 40:554–560, 2001. © 2001 Wiley‐Liss, Inc.
Respiratory diseases caused by occupational exposure to 1,5‐naphthalene‐diisocyanate (NDI): Results of workplace‐related challenge tests and antibody analyses
Authors: Baur X. , Chen Z. , Marczynski B.
Published: October 2004

Background

1,5‐naphthalene‐diisocyanate (NDI) is an aromatic diisocyanate with a very low vapor pressure which is mainly used in the automotive industry.

Methods

In the present study we described five cases with workplace‐related asthma and one case with extrinsic allergic alveolitis associated with pulmonary hemorrhage after NDI exposure.

Results

Corresponding to case histories, extrinsic alveolitis on asthmatic reactions in three subjects and a rhinitis reaction in one patient could be reproduced by inhalative challenge tests to NDI at a concentration of 10 ppb. Preliminary IgE and IgG antibody analyses in patients' sera did not produce significantly positive results.

Conclusions

According to the outcome of our tests and in comparison with several other studies, we conclude that NDI should be classified as potent airway‐sensitizing substance. Improved workplace conditions and decrease in threshold limit values should therefore be recommended. Am. J. Ind. Med. 39:369–372, 2001. © 2001 Wiley‐Liss, Inc.
Mortality among unionized construction plasterers and cement masons*
Authors: Stern Frank , Lehman Everett , Ruder Avima
Published: October 2004

Background

Plasterers perform a variety of duties including interior and exterior plastering of drywall, cement, stucco, and stone imitation; the preparation, installation, and repair of all interior and exterior insulation systems; and the fireproofing of steel beams and columns. Some of the current potential toxic exposures among plasterers include plaster of Paris, silica, fiberglass, talc, and 1,1,1‐trichloroethylene; asbestos had been used by the plasterers in the past. Cement masons, on the other hand, are involved in concrete construction of buildings, bridges, curbs and gutters, sidewalks, highways, streets and roads, floors and pavements and the finishing of same, when necessary, by sandblasting or any other method. Exposures include cement dust, silica, asphalt, and various solvents.

Methods

Proportionate mortality ratios (PMRs) and proportionate cancer mortality ratios (PCMRs) were calculated for 99 causes of death among 12,873 members of the Operative Plasterers' and Cement Masons' International Association who died between 1972 and 1996 using United States age‐, race‐, and calender‐specific death rates. Statistical significance (P value) of results was based upon the Poisson distribution.

Results

Among plasterers, statistically significant elevated mortality was observed for asbestosis, where the PMR reached 1,657 (P < 0.01) with eleven observed deaths and less than one death expected, for lung cancer (PCMR = 124, P < 0.01), and for benign neoplasms (PMR = 210, P < 0.05). Among cement masons, statistically significant elevated mortality was observed for cancer of the stomach (PCMR = 133, P < 0.01), benign neoplasms (PMR = 132, P < 0.01), and poisonings (PMR = 159, P < 0.05). Except for poisonings, which were not thought to be occupationally related, all of the statistically significant results occurred among those members who entered the union prior to 1950. However, the risk for lung cancer among plasterers was still elevated among those entering the union after 1970 as was the risk for stomach cancer among cement masons who entered the union after 1950.

Conclusions

The present study suggests that plasterers and cement masons still have elevated risks for certain diseases, especially lung and stomach cancer. Therefore, union members currently living should be screened for asbestos‐related diseases and educated about the future risks for these diseases.Am. J. Ind. Med.39:373–388, 2001. Published 2001 Wiley‐Liss, Inc.
Control of chemical risks during the treatment of soil contaminated with chlorophenol, creosote and copper‐chrome‐arsenic‐wood preservatives
Authors: Priha Eero , Ahonen Ilpo , Oksa Panu
Published: October 2004

Background

Exposure to chemicals in polluted soil was studied during the remediation of four polluted sites. They are sawmill areas contaminated with chlorophenols and polychlorinated dibenzo‐p‐dioxins and furanes (PCDD/F), wood impregnating plants contaminated with polycyclic aromatic hydrocarbons (PAH) from creosote oil, old gas works area contaminated with PAH, and a wood impregnation plant contaminated with copper‐chromium‐arsenic (CCA) preservative.

Methods

The exposure levels were determined by both air and biological monitoring.

Results

Air monitoring showed that the exposure levels were generally well below the current occupational exposure limits. The calculations indicated, however, that the lowest acceptable daily intake value recommended for PCDD/F by the U.S. Environmental Protection Agency was exceeded. Chlorophenol exposure was generally low. Exposure to volatile PAH was 0.038–0.884 mg/m3 and that to particulate PAH was 0.004–0.183 mg/m3. The biomonitoring results (urinary 1‐pyrenol) suggested that some exposure occurs, probably through the contamination of hands or skin absorption. At the sites contaminated with CCA salts, no exposure limits were exceeded.

Conclusions

The results generally suggest that the exposure of cleanup workers is generally below the current occupational exposure limits but that short‐term high exposure cannot be excluded. There was also some indication of poor skin protection, which should be improved when soil contaminated with PAH and creosote oil is handled. Am. J. Ind. Med. 39:402–409, 2001. © 2001 Wiley‐Liss, Inc.
Work environment factors, health, lifestyle and marital status as predictors of job change and early retirement in physically heavy occupations
Authors: Lund Thomas , Iversen Lars , Poulsen Kjeld B.
Published: October 2004

Background

The aim was to assess the rate at which waste collectors and municipal workers leave their job, to establish the outcome and to identify associated risk factors within work environment, health, lifestyle and marital status.

Methods

A questionnaire‐based survey among a cohort of 2,918 waste collectors and municipal workers was performed in 1994, with follow‐up 2.5 years later.

Results

Twenty‐five percent had left the job at follow‐up. Of these, 31% had changed jobs (associated with low decision authority), 16% were unemployed (associated with low skill discretion, pushing heavy loads and extreme bending of back), 10% received Disability Pension/long‐term sick leave (associated with low skill discretion, prevalent diseases, underweight and smoking), and 12% received Early Retirement Pension (associated with extreme bending of back and marital status).

Conclusions

The study suggests a potential for preventing people from leaving physically heavy occupations by improving the physical and psychosocial work environment. Am. J. Ind. Med. 40:161–169, 2001. © 2001 Wiley‐Liss, Inc.
Observed versus predicted carboxyhemoglobin levels in cellulose triacetate workers exposed to methylene chloride
Authors: Amsel Jon , Soden Kevin J. , Sielken Robert L. , Valdez‐Flora Ciriaco
Published: October 2004

Background

Occupational exposure to methylene chloride, together with carboxyhemoglobin concentrations, has not been studied previously.

Methods

Carboxyhemoglobin levels were measured in non‐smoking employees exposed to varying concentrations of methylene chloride during the manufacture of cellulose triacetate fibers. The observed carboxyhemoglobin levels were compared to predicted concentrations using a pharmacokinetic model.

Results

The presence of carboxyhemoglobin in non‐smokers exposed to methylene chloride results primarily from the metabolism of methylene chloride in the liver and exhibits a linear dose‐response relationship. The observed levels of carboxyhemoglobin in non‐smokers at the end of an 8‐hour shift depend upon exposures to methylene chloride that day but are independent of occupational exposures on previous days. The observed daily concentrations of carboxyhemoglobin are consistent with predicted concentrations using a pharmacokinetic model. While varying exposure patterns were shown to change the rate of metabolite formation at the end of shift, these same exposure patterns had almost no effect on the total amount of carbon monoxide in the blood.

Conclusion

While the present study addresses the relationship between methylene chloride, carbon monoxide, carboxyhemoglobin and ischemic heart disease, it does not address the issue of tumorigenicity, which is also the basis for the current U.S. Occupational Health and Safety workplace exposure limit of 25 ppm. This study provides support for the conclusion that the current American Conference of Governmental Industrial Hygienists 8‐hour Threshold Limit Value of 50 ppm adequately protects human health with regard to ischemic heart disease and carboxyhemoglobin formation among non‐smokers. Am. J. Ind. Med. 40:180–191, 2001. © 2001 Wiley‐Liss, Inc.
Interstitial fibrosis following hydrogen sulfide exposure
Authors: Duong Thanh X. , Suruda Anthony J. , Maier Lisa A.
Published: October 2004

This case report describes a patient with interstitial fibrosis 4 years after poisoning by hydrogen sulfide. Hydrogen sulfide causes pulmonary edema and is also toxic to the nervous system. Long‐term pulmonary sequelae of hydrogen sulfide poisoning has not been reported frequently in the literature. Am. J. Ind. Med. 40:221–224, 2001. © 2001 Wiley‐Liss, Inc.
Comparison of a traditional questionnaire with an icon/calendar‐based questionnaire to assess occupational history†
Authors: Engel Lawrence S. , Keifer Matthew C. , Zahm Shelia H.
Published: October 2004

Background

Self‐reported work histories are an essential tool for estimating exposure in many occupational epidemiologic studies. However, the transience of some occupations such as farm work can hamper recall, resulting in inaccurate reporting. To address this problem, we have developed an icon/calendar‐based questionnaire. This study compares work histories collected via this questionnaire to those collected via a traditional questionnaire.

Methods

Eighty‐nine farmworkers and non‐farmworkers were interviewed twice, 8–10 months apart, about their lifetime employment. In the first interview, subjects were asked to recount their entire work history, starting from the interview date and moving backwards in time (“traditional questionnaire”). In the second interview, subjects were first asked about important life events, which were recorded with icons on a calendar. They were then asked to recount their work history, which was recorded, job‐by‐job, on the calendar with icons (“icon‐calendar questionnaire”).

Results

Number of jobs and amount of work time accounted for since first employment were significantly greater using the icon‐calendar questionnaire than the traditional questionnaire, the disparity increasing with time from the date of interview. The ratio of number of jobs in the traditional questionnaire to number of jobs in the icon‐calendar questionnaire decreased from 100.0% in the most recent time period to 0.0% in the earliest time period. While the percentage of time explained by employment remained relatively constant across time periods in the icon‐calendar questionnaire, ranging from 86.3 to 98.9%, it rapidly decreased with time in the traditional questionnaire, from 77.9% in the most recent time period to 0.0% in the earliest time period.

Conclusions

The icon‐calendar questionnaire was more effective than the traditional questionnaire for obtaining complex work histories during interviews, producing a more complete picture of a person's work history. Am. J. Ind. Med. 40:502–511, 2001. Published 2001 Wiley‐Liss, Inc.
Test‐retest reliability of an icon/calendar‐based questionnaire used to assess occupational history†
Authors: Engel Lawrence S. , Keifer Matthew C. , Thompson Mary Lou , Zahm Shelia H.
Published: October 2004

Background

Self‐reported work histories can be critical for both epidemiologic and clinical purposes. However, the complexity of some work histories, such as those of migrant farm workers, can hamper recall, resulting in inaccurate reporting. Memory aids may reduce such error. This study assesses the reliability of work histories collected using such aids in the form of an icon/calendar‐based questionnaire.

Methods

Thirty‐one males engaged in farmwork and other manual labor for a median 28 years (range: 10–64) were interviewed twice, 8–14 months apart, about their lifetime employment. In each interview, subjects were asked about important life events, which were recorded with icons on a calendar. They were then asked to recount their work history, including for each job the tasks, crops or products handled, starting and ending dates, and location. This information was recorded, job‐by‐job, on the calendar with icons.

Results

Interquestionnaire agreement of cumulative reported employment duration (as measured by the correlation coefficient) was moderate to high across all time periods for certain crops (e.g., r = 0.69–0.92 for apple‐related work), by location (e.g., r = 0.76–0.95 for Washington State), and for agricultural work in general (r = 0.67–0.94), but was lower for specific tasks. Agreement of job counts was high for total work history for certain crops (e.g., r = 0.93 for apple‐related work), by location (e.g., r = 0.90 for Washington State), and for agricultural work in general (r = 0.89), but paradoxically decreased with proximity to the interview date. Agreement of both measures tended to be highest for those tasks and crops in which subjects reported spending the most time. Categorization of subjects into tertiles on the basis of either cumulative duration or counts produced results similar to those observed for job counts.

Conclusions

The icon‐calendar questionnaire is an effective tool for estimating cumulative duration of certain work categorizations among subjects with complex work histories. Am. J. Ind. Med. 40:512–522, 2001. Published 2001 Wiley‐Liss, Inc.
Comparability of data obtained from migrant farmworkers and their spouses on occupational history†
Authors: Colt Joanne S. , Engel Lawrence S. , Keifer Matthew C. , Thompson Mary Lou , Zahm Shelia Hoar
Published: October 2004

Background

Epidemiologic studies, particularly case‐control studies, often rely on proxy respondents to provide information about subjects' occupational histories. The quality of proxy‐reported information in occupational histories has never been evaluated for migrant farmworkers.

Methods

We compared occupational histories self‐reported by 31 farmworkers with those reported by their wives. The work histories were obtained using an icon/calendar‐based questionnaire that was designed to facilitate recall for migrant farmworkers, who typically have complex work histories.

Results

The work histories provided by proxy respondents contained 32% fewer jobs and accounted for 24% fewer years than the self‐reported histories. Correlations for lifetime duration of employment in different types of jobs were moderate to good for general agricultural jobs in Washington (0.70) and apple‐related jobs (0.65), which were held by virtually all of the farmworkers; correlations were moderate to poor for less common jobs and for specific types of tasks. Agreement was better after marriage than before, and for jobs held in the current year compared to other time frames. Overall, the ability of the spouses to provide occupational histories for farmworkers was within the range observed in studies involving other occupations and industries.

Conclusions

In studies involving farmworkers, when study subjects cannot be interviewed, spouses can provide useful information on occupational histories. However, the information should be used only for more generalized exposure assessments; it is most appropriate for estimating cumulative duration of agricultural work, or recent work, by place or for common crops. Am. J. Ind. Med. 40:523–530, 2001. Published 2001 Wiley‐Liss, Inc.
Analysis of ten candidate genes in autism by association and linkage
Authors: Philippe Anne , Guilloud‐Bataille Michel , Martinez Maria , Gillberg Christopher , Råstam Maria , Sponheim Eili , Coleman Mary , Zappella Michele , Aschauer Harald , Penet Christiane , Feingold Josué , Brice Alexis , Leboyer Marion ,   and the Paris Autism Research International Sibpair Study
Published: October 2004

We studied the possible involvement of ten candidate genes in autism: proenkephalin, prodynorphin, and proprotein convertase subtilisin/kexin type 2 (opioid metabolism); tyrosine hydroxylase, dopamine receptors D2 and D5, monoamine oxidases A and B (monoaminergic system); brain‐derived neurotrophic factor, and neural cell adhesion molecule (involved in neurodevelopment). Thirty‐eight families with two affected siblings and one family with two affected half‐siblings, recruited by the Paris Autism Research International Sibpair Study (PARIS), were tested using the transmission disequilibrium test and two‐point affected sib‐pair linkage analysis. We found no evidence for association or linkage with intragenic or linked markers. Our family sample has good power for detecting a linkage disequilibrium of 0.80. Thus, these genes are unlikely to play a major role in the families studied, but further studies in a much larger sample would be needed to highlight weaker genetic effects. © 2002 Wiley‐Liss, Inc.
Search for genes involved in Joubert syndrome: Evidence that one or more major loci are yet to be identified and exclusion of candidate genes EN1, EN2, FGF8, and BARHL1
Authors: Blair Ian P. , Gibson Roxanne R. , Bennett Craig L. , Chance Phillip F.
Published: October 2004

Joubert syndrome (JS) is a rare autosomal recessive malformation syndrome involving agenesis or dysgenesis of the cerebellar vermis with accompanying brainstem malformations. JS is further characterized by hypotonia, developmental delay, intermittent hyperpnea, and abnormal eye movements. The biochemical and molecular basis of JS remains unknown, although several genes that are crucial in the development of the cerebellum have been proposed as attractive candidate genes. JS is clinically heterogeneous; this, together with previous linkage analyses, suggests that there may also be genetic heterogeneity. A locus for JS was previously identified on chromosome 9q34 by linkage analysis in a consanguineous family of Arabian origin. A putative second JS locus was recently suggested when a deletion on chromosome 17p11.2 was observed in a patient with Smith‐Magenis syndrome and JS phenotype. We have investigated a cohort of apparently unrelated North American JS pedigrees for association with the loci on chromosomes 9q34 and 17p11.2 and excluded them in all cases where data were informative. Analysis of an additional 21 unrelated JS patients showed no evidence of homozygosity at the 9q34 and 17p11.2 loci that would suggest inheritance of founder JS mutation(s) or unreported consanguinity. Together, these data suggest that one or more major loci for JS remain to be identified. Consequently, we undertook mutation analysis of several functional candidate genes, EN1, EN2, and FGF8, in a total of 26 unrelated JS patients. Our data suggest that all of these genes may be excluded from a direct pathogenic role in JS. The BARHL1 gene, which localizes to chromosome 9q34 and has previously been proposed as a strong positional candidate gene for JS, was also investigated and excluded from involvement in JS that is linked to chromosome 9q34. © 2002 Wiley‐Liss, Inc.
Sex differences in shared genetic and environmental influences between conduct disorder symptoms and marijuana use in adolescents
Authors: Miles Donna R. , van den Bree Marianne B.M. , Pickens Roy W.
Published: October 2004

The association between conduct disorder (CD) symptoms and marijuana use (MU) was assessed in 1,480 adolescent twins participating in the National Longitudinal Study on Adolescent Health. A strong association was found between CD and MU for both males (r = .38, P < .01) and females (r = .31, P < .01). Structural equation modeling on age‐corrected rank normalized scores using the program Mx indicated significant gender differences in the genetic and environmental contributions to MU. Additive genetic influences were comparable in size for males (29%) and females (24%). However, for females the influence of common environmental influences was greater (58%) than for males (36%). There was also evidence of greater common environmental influences for females, as well as greater genetic influences for males for CD, but these differences did not reach significance. In addition, for CD common environmental influences did not differ significantly from zero. Additive genetic influences accounted for 61% of the variance in CD, with the remainder being of unique environmental origin. Bivariate genetic analyses suggested a moderate genetic correlation between CD and MU (rg = .28) and a low unique environmental correlation (re = .14). These results suggest that CD and MU share genetic influences, while environmental influences tend to be more specific to each behavior. These findings may have implications for the prevention and treatment of CD and substance use among adolescents. © 2002 Wiley‐Liss, Inc.
Survival, growth, health, and reproduction following nursery rearing compared with mother rearing in pigtailed monkeys (Macaca nemestrina)
Authors: Sackett Gene P. , Ruppenthal Gerald C. , Davis Arthur E.
Published: October 2004

Nursery‐reared primates do not experience psychological “maternal bonding” or immunological benefits of breast milk, so they are expected to be inferior to mother‐raised monkeys in growth, health, survival, reproduction, and maternal abilities. Studies of nursery‐reared monkeys support aspects of this prediction for infants deprived of social contact or raised in pairs. We present colony record data on 1,187 mother and 506 nursery‐raised monkeys, 2–10 yr of age, living in mixed groups. We found no group differences in survival, growth, clinical treatments for disease or bite wounds, or pregnancy outcome and neonatal deaths. Nursery males given breeding opportunities produced an average of 24 offspring. In addition to 24‐hr personnel present on every day of the year, we believe that three of our procedures account for differences between our results and other reports. Our infants received 1) intensive human handling, 2) daily social interaction in a playroom, and 3) success and failure experience during learning and cognitive testing. We do not advocate rearing primates without mothers, but we conclude that these procedures are sufficient for producing physical health and adaptive juvenile and adult social skills in nursery‐raised monkeys. Am. J. Primatol. 56:165–183, 2002. © 2002 Wiley‐Liss, Inc.
Adhesive and flame resistance behavior of poly(arylene ether phosphine oxide) (PEPO) and PEPO‐modified epoxy resins
Authors: Jeong K. U. , Park I. Y. , Kim I. C. , Yoon T. H.
Published: October 2004

Poly(arylene ether phosphine oxide) (PEPO) with controlled molecular weights and amine end‐groups was synthesized, and used as an adhesive, a coating material for adherend or a modifier for diglycidyl ether of bisphenol A (DGEBA)‐based epoxy resins. Closely related poly(arylene ether sulfone) and commercial polyethersulfone, Udel® P‐1700, were also utilized for comparison purposes. Adhesive behavior was measured via single lap shear samples as a function of coated polymer type, test temperature (R.T. and 100°C), and aging condition in boiling distilled water or 5% salt water. Flame resistance of PEPO and PEPO‐modified epoxy resin was evaluated by TGA and a flame test. PEPO exhibited better adhesive properties than PES or Udel® P‐1700. PEPO coating on an Al adherend markedly improved adhesive property of PES and Udel® even at 100°C, and after aging study failure mode changed from adhesive to cohesive with the PEPO. Aminophenyl terminated PEPO‐modified epoxy resins also exhibited highly improved adhesive behavior and flame resistance, compared to control samples. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1198–1205, 2001
Novel optical material: Polyarylates with azomethine side‐chain groups
Authors: Zadrożna I. , Mysłek M.
Published: October 2004

A number of NLO polymers were obtained, in which aromatic polyester is a matrix and the chromophores are incorporated into the form of a side chain. Special monomers are based on 2,2‐bis(3‐amino‐4‐hydroxyphenyl)propane; they contain an azomethine bond and various electron‐acceptor groups (nitro, cyanide, and fluoride) as substituents in the side‐chain aromatic ring. The effect of the type of the electron‐acceptor substituent, its substitution position in the aromatic ring with respect to the azomethine bond, and special monomer concentration on the optical, mechanical, and thermal properties of the whole system was studied. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1374–1382, 2001
Die swell of thermoplastic polyurethanes: A peculiar behavior
Authors: Dufrancatel‐Veiller L. , Lacrampe M. F. , Pabiot J.
Published: October 2004

The instantaneous and equilibrium isothermal die swell ratios of thermoplastic polyurethanes have been measured by two methods. The incidence of some structural, geometrical, and processing parameters has been analyzed. The experimentation reveals the atypical behavior of these polymers related to a structural evolution during processing that greatly depends on the residence time in temperature under shearing and that probably results from the cumulated effects of multiple recombinations and chain cuts. This thermo‐mechanical degradation affects the rheological properties of these polymers. The maximal behavior variations are observed for short times and stabilize above a specific critical time. Taking into account the effect of these rheological alterations on the generating mechanisms of die swell allows us to interpret all the experimental results (atypical or not) in terms of magnitude and direction of variation of the phenomenon. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1710–1724, 2001
Degradation of new cellulose‐based complex material
Authors: Ou Yifang , Huang Qiulian , Chen Jianan
Published: October 2004

The degradation of a kind of cellulose‐based complex material was investigated by the soil bury and exposure methods. The results showed that the average molecular weight of the sample decreased 66.7% and the copper number increased from 1.32 to 7.58 after 9 weeks as measured by the soil bury method. Meanwhile the average molecular weight decreased 38.7% and the copper number increased from 1.32 to 5.00 after 14 weeks of exposure under the sun. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 809–812, 2001
Comparison of gas‐ and liquid‐phase polymerization of propylene with heterogeneous metallocene catalyst
Authors: Meier G. B. , Weickert G. , van Swaaij W. P. M.
Published: October 2004

Sorption measurements are executed to study the sorption behavior of propylene in a semicrystalline polymer. Decreasing values for the Flory–Huggins interaction parameter with increasing temperature are obtained. Large deviations are found, especially at higher temperatures, compared to data from the literature. Propylene is polymerized in liquid and gaseous propylenes with Me2Si[Ind]2ZrCl2/MAO/SiO2 as the metallocene catalyst. Lower relative reaction rates are found in the gas phase compared to the experiments in the liquid phase. The activation energies from the experiments in both phases are on the same order of magnitude. However, the literature versus experimental sorption data has a large effect on the determined kinetic parameters. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1193–1206, 2001
Grafting vinyl monomers onto silk (Bombyx mori) using different initiators: Properties of grafted silk
Authors: Tsukada Masuhiro , Arai Takayuki , Freddi Giuliano , Imai Tsuneo , Kasai Nobutami
Published: October 2004

The graft–copolymerization of silk with methacrylamide (MAA), 2‐hydroxyethyl methacrylate (HEMA), and methyl methacrylate (MMA) was studied using three different free‐radical initiators: an inorganic peroxide [ammonium persulfate (APS)] and two azo compounds [2,2′‐azobisisobutyronitrile (AIBN) and 2,2′‐azobis(2‐methylpropionamidine) dihydrochloride (ADC)]. The rate and yield of grafting followed the order: APS > AIBN > ADC. The performance of AIBN was close to that of APS in terms of weight gain attained. The degree of yellowing of grafted silk varied as a function of the initiator–monomer system used. APS induced the highest degree of yellowing, regardless of which monomer was used, whereas silk grafted with the MAA/AIBN system displayed the lowest level of yellowing. Moisture regain of grafted silk changed as a function of the hydrophilic/hydrophobic character of the grafted polymer, regardless of the kind of initiator used. Accordingly, tensile properties showed a tendency to decrease with increasing weight gain of grafted silk, the extent of which was independent of the kind of monomer and initiator used. The different initiators did not induce any appreciable change in the fine structure of silk, as demonstrated by optical measurements. Uneven surface deposition of homopolymer was detected to variable extent with MMA and HEMA grafting, whereas the surface of MAA‐grafted silk was completely free of any foreign deposit, independently of the initiator used. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1401–1409, 2001
Physicochemical and thermal properties of phenol–formaldehyde‐modified polyphenol impregnate
Authors: Sekaran G. , Thamizharasi S. , Ramasami T.
Published: October 2004

Tannin, a natural polymer belonging to the polyphenolic group of compounds, is widely used in the leather industry, specifically as a tanning agent for the conversion of putrescible collagen fibers into leather matrix during the leather‐manufacturing process. Unspent tannin poses a serious environmental threat to the public because it has a very high half‐life, leading to groundwater pollution when discharged into soil. Attempts have been made to separate tannins through chemical means and recovered tannin needs to be encapsulated for its safe disposal. In the present study the recovered tannin was impregnated in phenol–formaldehyde (PF) resin. Spectroscopic and thermogravimetric (IR, NMR, TGA and DSC) studies revealed that the modified polyphenol was held physically in the impregnate. The impregnated matrix showed resistance to mineral acids, strong alkalis and organic solvents and was tested for its adhesive property on leather sheets. The leather that bonded with PF‐modified polyphenol impregnate (PFT) had a 27% increase in peel strength and a 40% increase in lap shear strength as compared to the sample bonded with PF resin. The corrosive resistance result of the PFT resin shows it has potential application as an anticorrosive paint in the paint industry. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1567–1571, 2001
Comparative rheological characteristics of industrial polyflavonoid tannin extracts
Authors: Garnier S. , Pizzi A. , Vorster O. C. , Halasz L.
Published: October 2004

Commercial, industrially produced mimosa, quebracho, pine, and pecan polyflavonoid tannin extracts water solutions of different concentrations were examined by rheometry by measuring dynamic moduli both as a function of strain amplitude and at varying frequency. The water solutions of these materials have been found to behave in general mainly as viscous liquids at the concentrations that are generally used for their main industrial applications. Clear indications of viscoelastic response are also noticeable, among these the crossover of the elastic and viscous moduli curves at the lower concentrations of the range investigated, with some differences being noticeable between each tannin and the others—pine and quebracho tannin extracts showing the more marked viscoelastic behavior. Other than pH dependence (and related structural considerations), the parameters found to be of interest as regards the noticeable viscoelastic behavior of the tannin extracts were the existence in the solutions of labile microstructures that can be broken by applied shear. This is supported by the well‐known thixotropic behavior of concentrated, commercial polyflavonoid tannin extracts water solutions. Such microstructures appear to be due (1) to the known colloidal interactions of these materials already reported, or (b) to other types of secondary interactions between tannin oligomers and particularly between tannin and carbohydrate oligomers. The latter is supported by the dependence of this effect from both the average molecular masses of the tannin and of the carbohydrate oligomers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1634–1642, 2001
Effect of comonomers on the rate of crystallization of PET: U‐turn comonomers
Authors: Connor Daniel M. , Allen Scott D. , Collard David M. , Liotta Charles L. , Schiraldi David A.
Published: October 2004

The effect of incorporating phthalate, 1,8‐naphthalenedicarboxylate, and 1,8‐anthracenedicarboxylate structural units on the crystallization rate of PET are evaluated by isothermal and dynamic calorimetry. Although all of the comonomers retard crystallization, the 1,8‐naphthalene unit shows no concentration dependence between 2.5 and 10% incorporation, in contrast to the smaller phthalate and larger anthracene units. The greater rate at which the 1,8‐naphthalene copolymer crystallizes, relative to that of the other copolymers, is consistent with the notion that the U‐turn geometry induces chain folding and nucleates crystallization. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1675–1682, 2001
Release of indomethacin from a novel chitosan microsphere prepared by a naturally occurring crosslinker: Examination of crosslinking and polycation–anionic drug interaction
Authors: Mi Fwu‐Long , Sung Hsing‐Wen , Shyu Shin‐Shing
Published: October 2004

Novel chitosan microspheres with lower cytotoxicity were fabricated in this study and their drug release characteristics were investigated. Genipin, a naturally occurring crosslinking reagent that has been used in herbal medicine and in the production of food dye, was used to prepare crosslinked chitosan microspheres by a water‐in‐oil dispersion method. The crosslinking mechanism examined by FTIR and 13C–NMR suggests that the crosslinking of chitosan by genipin leads to the formation of secondary amide and heterocyclic amino linkage. The polycation–anionic drug interaction between chitosan and indomethacin was pH dependent and could affect the dissolution property of indomethacin. By examination of the release profiles of the crosslinked chitosan microsphere, it was found that the release of indomethacin from the microsphere was sustainable and influenced by factors such as crosslinking of microsphere and chitosan–indomethacin interaction, thus establishing crosslinked chitosan microsphere as a very promising polymeric carrier for drug release. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1700–1711, 2001
Morphological and mechanical properties of PP/ABS blends compatibilized with PP‐g‐acrylic acid
Authors: Patel Alpesh C. , Brahmbhatt Ragesh B. , Sarawade B. D. , Devi Surekha
Published: October 2004

Polypropylene (PP) and acrylonitrile–butadiene–styrene (ABS) blends were prepared by a melt extrusion process. PP‐g‐acrylic acid was used as a compatibilizer. Blends with various compositions of PP, compatibilizer, and ABS were prepared and studied for morphological and mechanical properties. PP‐rich ternary blends showed good morphological and mechanical properties. The use of 5 wt % PP‐g‐acrylic acid as a compatibilizer resulted in a fine and homogeneous dispersion of the ABS phase in the PP phase. The experimental data of the tensile modulus showed good agreement in PP‐rich compositions with that generated from Kerner's model with perfect adhesion. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1731–1741, 2001
Effect of montmorillonite on thermal and moisture absorption properties of polyimide of different chemical structures
Authors: Tyan Horng‐Long , Wu Chao‐Yin , Wei Kung‐Hwa
Published: October 2004

The thermal properties and the moisture absorption of three types of polyimide/montmorillonite nanocomposite were investigated: 3,3′,4,4′‐biphenyltetracarboxylic dianhydride‐4,4′‐oxydianiline (BPDA‐ODA); pyromellitic dianhydride‐ODA (PMDA‐ODA); and 3,3′,4,′‐benzophenone tetracarboxylic dianhydride‐ODA (BTDA‐ODA). The inhibition effect on in‐plane coefficients of thermal expansion (CTE) and moisture absorption of these polyimide nanocomposites by layered silicates from montmorillonite was found to decrease with the crystallinity in the pristine polyimides. The largest reduction, 30% in in‐plane CTE occurred in the case of amorphous BTDA‐ODA containing 5 wt % montmorillonite as compared with that of pure BTDA‐ODA, while the reduction in in‐plane CTE was 20% for the case of semicrystalline BPDA‐ODA. The maximum reduction in moisture absorption, 43%, also took place for the case of 3/97 ODA‐Mont/BTDA‐ODA as compared with that of pure BTDA‐ODA, whereas the semicrystalline 1/99 PPD‐Mont/BPDA‐ODA showed a 30% reduction as compared with that of pure BPDA‐ODA. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1742–1747, 2001
Reaction kinetics for solid‐state polymerization of poly(ethylene terephthalate)
Authors: Duh Ben
Published: October 2004

A simple kinetic model capable of describing the behaviors of solid‐state polymerization (SSP) of poly(ethylene terephthalate) (PET) has been developed. According to this model, there are two types of end groups, namely active end groups and inactive end groups, and the solid‐state polycondensation reaction is a second‐order reaction with respect to the active end group concentration. The inactive end groups include chemically dead end groups and functional end groups that are immobilized by the crystalline structure. The inactive end group concentration determines the ultimate intrinsic viscosity (IV) or molecular weight achievable in the SSP—the lower the inactive end group concentration, the higher the ultimate IV. Four pulverized PET prepolymers with IV values ranging from 0.20 to 0.35 dL/g were solid‐state polymerized in a fluid‐bed reactor at temperatures between 200 and 230°C to generate data to test the model. The experimental results fit the proposed rate equations very well, confirming the adequacy of the proposed kinetic model. Under these SSP conditions, the activation energy is about 23.6 kcal/mol and the average SSP rate about doubles with each 10°C increase in temperature. The rate constant increases, while the inactive end group concentration decreases, with increasing temperature and prepolymer IV. This explains why the reaction rate and the ultimate IV increase with increasing prepolymer IV as well as temperature in the SSP of PET. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1748–1761, 2001
Effect of hydrolysis on porosity of cellulose acetate reverse osmosis membranes
Authors: Košutić K. , Kunst B.
Published: October 2004

The alkaline hydrolysis of asymmetric cellulose acetate membranes was investigated. The changes of cellulose triacetate and cellulose diacetate membrane performances caused by hydrolysis of the membrane material were measured, and the data were analyzed in terms of pore size distributions and effective number of pores in the upper membrane layer before and after hydrolysis. The resulting membranes rejection factors decrease of 10–25%, and a noticeable permeation rates increase were caused by closing of a part of the smallest “network” membrane pores and by increasing the size of the other pores. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1768–1775, 2001
Water crosslinking reactions of silane‐grafted polyolefin blends
Authors: Shieh Yeong‐Tarng , Chuang Hui‐Chun , Liu Chih‐Ming
Published: October 2004

Water crosslinking reactions of LDPE, PP, LLDPE, and the LDPE/PP and LDPE/LLDPE blends are investigated. Degrees of crosslinking of these samples are quantitatively compared and discussed in detail in terms of crosslinking ability, phase‐separation behavior, molecular weight (or viscosity), morphology of the constituents in blends, or in the pure state. It is found that PP gives negligible crosslinking reactions in the pure state and in blends with LDPE. LDPE and LLDPE are both capable of giving considerable degrees of crosslinking, with LLDPE giving a higher degree of crosslinking than LDPE at all conditions studied. Degrees of crosslinking of the LDPE/LLDPE blends are not linearly but are zigzagly related to the compositions of the blends with the LDPE/LLDPE = 50/50 blend giving a relatively high degree of crosslinking at 100, 120, and 140°C for a certain time except the condition at 140°C for 12 h compared with the LDPE/LLDPE = 75/25 and 25/75 blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1799–1807, 2001
Adherence evaluation of paint coatings using a three‐point flexure test and acoustic emission
Authors: Devos P. , Baziard Y. , Rives B. , Michelin P.
Published: October 2004

The adherence of paint coatings on aluminum substrates was tested using a three‐point flexure test (TPFT) combined with acoustic emission (AE) evaluation. The mechanical test was defined according to the French Standard. During bending of the paint‐coated specimen, acoustic emission signals were recorded and analyzed. Substrate pretreatments were chosen to show a set of visual interfacial ruptures and a set of visual cohesive ruptures in the paint. The formulation of the paint was fixed by industrial regulations. The varying nature of systems showed different AE patterns, particularly for two types of specimens: those that corresponded to solvent degreasings and the others to aqueous chemical pretreatments. The behavior of the paint coating differed, with significant AE, damage, and crack propagation in the first case and instantaneous phenomena in the other case. It is then possible to establish a relationship between the analysis of the recorded AE signal and the type of joint rupture. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1848–1857, 2001
Effect of CaCO3 on the performance of Partex surface modification by ultraviolet radiation curing method
Authors: Rahman M. Mizanur , Khan Mubarak A. , Uddin M. Khabir , Idriss Ali K. M. , Mustafa A. I.
Published: October 2004

Several UV‐curable formulations containing epoxydiacrylate (EB‐600) oligomer with a tri‐functional monomer, trimethylol propane triacrylate (TMPTA), and photoinitiator Irgcure‐369 were developed to improve the surface of Partex. Filler or extender CaCO3 was incorporated into the solution. Thin polymer films were prepared on glass plate with these formulated solutions and finally applied on polished Partex surface, and both were cured under UV‐radiation. The properties of UV‐cured thin films were studied as a function of CaCO3 concentration. Pendulum hardness and gel content were found to decrease on glass plate with the increase of CaCO3 concentration. Pendulum hardness, scratch hardness, and abrasion resistance of the cured Partex were found to be higher with the increase of CaCO3 content up to 4%. Thus, the formulation containing 4% CaCO3 showed the best performance over all formulations containing CaCO3. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1858–1867, 2001