bluuebunny/crossref_metadata_2025 huggingface dataset:
Examining the Role of Attitudinal Factors in Shaping Fire Prevention Intentions: A Study of Response Efficacy in Public Markets of Tanzania
Authors: Mwakatage Billy J. , Golyama Bahati
Published: January 2024

The need of this study was to examine the moderating effects of attitude on the relationship between response efficacy and prevention intention of fire outbreaks in public markets. This research utilized quantitative research methods, surveying 384 participants consisting of traders and market management in the Dar es Salaam Region. A simple random sampling technique was employed to select respondents from 10 markets, and data analysis was conducted using a structural equation model. Findings show that attitudes moderate the relationship between perceived response efficacies towards prevention intention of fire outbreaks in public markets. The result shows that the effects of perceived response efficacy to attitudes (CR = 0.114, P = 0.035 and SRW = 0.480) and path leading from attitudes to prevention intention on outbreaks of fire in public markets was (CR = 0.2.653, P = 0.008 and SRW = 0.931). The study recommends that building attitudes on fire prevention should be a continuous process in public market in Tanzania.
Electron transfer in the redox reaction of cobalt tetraphenylporphyrin incorporated in a Nafion film
Authors: ZHAO FENG , ZHANG JIAN , KANEKO MASAO
Published: August 2002

Potential step chronoamperospectrometry (PSCAS) was carried out to analyze electron transfer in the redox reaction processes of 5,10,15,20-tetraphenylporphyrinatocobalt(II) ( Co II TPP (-2)) incorporated in a Nafion film. The reactions of Co II TPP (-2) to [ Co III TPP (-2)]+ and of [ Co III TPP (-2)]+ to Co II TPP (-2) took place through a diffusion mechanism, as confirmed by the first-order initial reaction rate with respect to the complex concentration in the matrix. However, the reaction of [ Co III TPP (-2)]+ to [ Co III TPP (-1)]2+ occurred by an electron-hopping mechanism, as confirmed by the second-order initial reaction rate with respect to the complex concentration. The fraction of electroactive complex (Rct) increased with the sample time after the potential step until it reached saturation. In the reactions of Co II TPP (-2) to [ Co III TPP (-2)]+ and of [ Co III TPP (-2)]+ to Co II TPP (-2), Rct approached 1.0, while in the reaction of [ Co III TPP (-2)]+ to [ Co III TPP (-1)]2+, only about 0.3 was reached. The apparent diffusion coefficient (Dapp) decreased in the order of [ Co III TPP (-2)]+ to Co II TPP (-2) > Co II TPP (-2) to [ Co III TPP (-2)]+>[ Co III TPP (-2)]+ to [ Co III TPP (-1)]2+. The different behavior of these redox reactions was ascribed to the microenvironment of the redox species in the matrix, interaction of the redox centers, especially the product with the framework, and counter ion migration.
Chromatographic behaviour of some porphyrins and their complexes with Zn, Pd(II) and Cu(II)
Authors: UVAROVA M. I. , BRYKINA G. D. , SHPIGUN O. A.
Published: August 2002

In this work the influence of the porphyrin structure and of the nature of the mobile phase upon retention parameters is examined by means of reversed phase high-performance liquid chromatography (HPLC). Acetonitrile–ethyl acetate and other mixtures were used as eluents. An increase in the retention of azo- and benzosubstituted porphyrins as well as of those containing a large number of carbon atoms as substituents of macrocycles may be noted. A variation in the polarity of the mobile phase affects the retention of the ligands more than that of their zinc complexes. The retention of the most hydrophobic compounds may be well described in coordinates lg k'– lg M. For less hydrophobic porphyrins these dependences are close to linear only within limited intervals of mobile phase ethyl acetate concentration. The best separation of zinc complexes was achieved with acetonitrile as the eluent. The detection limit of porphyrin ligands and complexes with metals is n × 10-8 M.
Something Old, Something New: Adult Learning Theory for the Twenty‐First Century
Authors: Merriam Sharan B.
Published: August 2002

This chapter summarizes the recent additions to the knowledge base of adult learning theory and concludes with some thoughts on how these contributions are expanding adult learning theory.
Involuntary memories of emotional events: do memories of traumas and extremely happy events differ?
Authors: Berntsen Dorthe
Published: August 2002

Laboratory studies of voluntary memories have been criticized for being too insensitive in detecting the impact of trauma. To overcome this, 12 traumatized undergraduates participated in a diary study of involuntary memories (8 females, 4 males, mean age 25 years, range 19–33). Six participants had encountered their trauma more than five years ago, six within the most recent year. No group differences were found on frequency and vividness of involuntary trauma memories, their mood‐impact and ability to trigger a physical reaction. Marked differences were found between traumatic and non‐traumatic involuntary memories on the same variables. The results indicate that trauma memories are extraordinarily persistent. This was confirmed by a comparative study of memory for extremely happy events (9 females, 5 males, 26 years, range 20–38). Further, it was demonstrated that highly vivid involuntary memories—so‐called flashbacks—are not limited to trauma nor even to emotionally negative events. Copyright © 2001 John Wiley & Sons, Ltd.
Rotationally molded polyethylene: Structural characterization by x‐ray and microhardness measurements
Authors: Cramez Maria Clara , Oliveira Maria Jovita , Fakirov Stoyko , Crawford Robert James , Apostolov Anton Atanassov , Krumova Marina
Published: August 2002

Rotationally molded polyethylene (PE) blended in two ways (turbo blending and extrusion) with nucleating and nonnucleating pigments is structurally characterized by wide‐ and small‐angle x‐ray scattering (WAXS and SAXS, respectively), DSC and microhardness measurements. Morphological observations are performed by polarized light microscopy. The melting temperature and the degree of crystallinity (from both DSC and WAXS) remain essentially constant regardless of sample preparation and type of pigment. The same holds for the crystal sizes from WAXS and the lamella thickness from SAXS. Only the values of microhardness depend on the type of pigment, increasing about 10% when a nucleating type is used. The almost constant values of these properties, contrasting to the spherulitic morphology, are explained by the fact that the processing conditions in rotational molding are very favorable for crystallization. As a consequence, optimal crystalline structure is achieved, which masks significantly the effect of pigments and blending conditions on the crystallization behavior of polyethylene. © 2001 John Wiley & Sons, Inc. Adv Polym Techn 20: 116–124, 2001
Frequency of the 677 C→T mutation of the methylenetetrahydrofolate reductase gene among Kuwaiti sickle cell disease patients
Authors: Adekile A.D. , Kutlar F. , Haider M.Z. , Kutlar A.
Published: August 2002

Sickle cell disease (SCD) is relatively mild among Kuwaiti Arabs. However, an atypical subset of patients exists with frequent, severe vaso‐occlusive crisis and osteonecrosis. The thermolabile variant of MTHFR, resulting from a C→T mutation at nucleotide 677, has been shown to be associated with hyperhomocysteinemia, which is an important risk factor for premature vascular disease. We have screened an unselected group of 41 Kuwaiti SCD patients (33 SS and 8 Sβ0‐thal) attending the Hematology Clinic of Kuwait University Teaching Hospital for the MTHFR mutation, using a PCR‐RFLP method. The patients were aged 2–41 years (mean of 12.8 ± 8.6). One (2.4%) individual was homozygous for the mutation while 15 (36.6%) were heterozygous, giving an allele frequency of 20.7%. Twenty‐one patients (14 SS and 7 Sβ0‐thal) were screened for osteonecrosis using MRI of the hip (spin‐echo T1‐ and T2‐weighted images). Seven (33.3%) had varying degrees of osteonecrosis, among whom the frequency of the 677 C→T allele was 21.4%. The frequency was identical among those without osteonecrosis. Although the allele frequency is higher among our patients compared to American SS patients, our results do not suggest an association with osteonecrosis. Am. J. Hematol. 66:263–266, 2001. © 2001 Wiley‐Liss, Inc.
Evolutionary demography and intrahousehold time allocation: School attendance and child labor among the Okavango Delta Peoples of Botswana
Authors: Bock John
Published: August 2002

The ways in which resources are allocated within households and/or families, especially within the context of children's time allocation to labor and schooling, has long been a subject of concern to demographers and economists. Differential investment in children and resulting differences in activity budgets may have significant effects on children's growth and development as well as on aspects of reproduction. This study uses predictions regarding parental investment in the embodied capital of offspring generated by evolutionary theory to examine the pattern of children's time allocation to labor and schooling among the Okavango Delta Peoples of Botswana. Models incorporating individual costs and benefits of resource allocation, conflicts of interests between men and women and between parents and offspring, and the effects of family composition, subsistence ecology, and gender are developed and applied to data on time allocation, household demography, and household economy. Several findings emerged: (1) The availability of alternative productive tasks strongly affects intra‐ and intergenerational labor substitution. (2) The presence of similarly aged children of the same sex within the household decreases the likelihood of both boys and girls engaging in a specific productive activity and increases the likelihood of children's school attendance. (3) Birth order, the labor needs of the household, and parents’ marital status all affect school attendance. These results have implications for understanding the determinants of children's time allocation to labor and schooling and consequent impacts on development, health, and welfare. Am. J. Hum. Biol. 14: 206–221, 2002.© 2002 Wiley‐Liss, Inc.
A prospective study of computer users: II. Postural risk factors for musculoskeletal symptoms and disorders
Authors: Marcus Michele , Gerr Fredric , Monteilh Carolyn , Ortiz Daniel J. , Gentry Eileen , Cohen Susan , Edwards Alicia , Ensor Cindy , Kleinbaum David
Published: August 2002

Background

Despite widespread recommendations regarding posture during computer use, associations between specific postures and musculoskeletal health are not well characterized.

Methods

Six hundred and thirty‐two newly hired computer users were followed prospectively to evaluate associations between posture and neck or shoulder (N/S) and hand or arm (H/A) musculoskeletal symptoms and musculoskeletal disorders. Participants' postures were measured at entry and they reported symptoms on weekly diaries. Participants reporting symptoms were examined for specific disorders. Multivariate Cox regression models were used to estimate associations between postural variables and risk of symptoms and disorders, controlling for confounding variables.

Results

Keying with an inner elbow angle > 121°, greater downward head tilt, and presence of armrests on the participants chair were associated with lower risk of N/S symptoms or N/S disorders. Keying with elbow height below the height of the “J” key and the presence of a telephone shoulder rest were associated with a greater risk of N/S symptoms or N/S disorders. Horizontal location of the “J” key > 12 cm from the edge of the desk was associated with a lower risk of H/A symptoms and H/A disorders. Use of a keyboard with the “J” key > 3.5 cm above the table surface, key activation force > 48 g, and radial wrist deviation of > 5° while using a mouse was associated with a greater risk of H/A symptoms or H/A disorders. The number of hours keying/week was associated with H/A symptoms and disorders.

Conclusions

The results suggest that the risk of musculoskeletal symptoms and musculoskeletal disorders may be reduced by encouraging specific seated postures. Am. J. Ind. Med. 41:236–249, 2002. © 2002 Wiley‐Liss, Inc.
Predictors of shoulder and back injuries in nursing home workers: A prospective study
Authors: Myers Douglas , Silverstein Barbara , Nelson Nancy A.
Published: August 2002

Background

Nursing assistants (NAs) working in nursing homes have among the highest back and shoulder injury rates in the US. Incidence, severity, and cost of non‐traumatic soft tissue musculoskeletal disorders in the nursing home industry in Washington State are quite high.

Methods

To determine whether resident characteristics data reported on the Health Care Financing Administration Minimum Data Set (MDS) could be used as a surrogate measure of cumulative exposure to physical loads, we conducted an 18‐month prospective study in one nursing home.

Results

The combined NA injury incidence rate (IR) was 45.8 self‐reported back and shoulder injuries per 100 [FTE] workers per year. In general, MDS reported resident characteristics failed to predict risk with the exception of exposure to loss of voluntary leg mobility (OR = 1.11 per person‐shifts of exposure, 95% CI [0.97–1.27]), with the highest risk on the day shift (OR = 1.15, 95% CI [0.95–1.40]).

Conclusions

These findings suggest social integration and work organization issues may be more important predictors of back and shoulder injuries in nursing assistants than reported resident characteristics as measured by the MDS. Am. J. Ind. Med. 41:466–476, 2002. © 2002 Wiley‐Liss, Inc.
Gene‐based SNP genetic association study of the corticotropin‐releasing hormone receptor‐2 (CRHR2) in major depression
Authors: Villafuerte Sandra M. , Del‐Favero Jurgen , Adolfsson Rolf , Souery Daniel , Massat Isabelle , Mendlewicz Julien , Van Broeckhoven Christine , Claes Stephan
Published: August 2002

An increasing amount of data suggests that affective disorders are related to dysregulation of the hypothalamic‐pituitary‐adrenal (HPA) axis, the stress‐response system. Corticotropin‐releasing hormone receptor‐2 (CRHR2)‐deficient mice display a stress‐sensitive and anxiety‐like phenotype suggesting that the CRHR2 is a plausible functional candidate gene influencing the reactivity of the HPA axis and therefore the liability to develop affective disorders. In this study, a gene‐based single nucleotide polymorphism (SNP) map of the corticotropin‐releasing hormone receptor 2 (CRHR2) was constructed containing one synonymous cSNP in exon 10, two intronic SNPs, and two SNPs in the 5′ upstream regulatory region. No significant difference in allele or genotype frequency was found for four out of the five SNPs between Belgian unipolar (UP) patients and age‐, gender‐, and ethnicity‐matched controls. The cSNP did show allelic and genotypic association with borderline significance (P = 0.04). However, a replication study of this cSNP in a bipolar sample of Belgian origin and a Swedish UP sample did not show significant differences in allele and genotype frequencies. © 2002 Wiley‐Liss, Inc.
Mutational analysis of the Sonic Hedgehog gene in 220 newborns with oral clefts in a South American (ECLAMC) population†
Authors: Orioli Iêda M. , Vieira Alexandre R. , Castilla Eduardo E. , Ming Jeffrey E. , Muenke Maximilian
Published: August 2002

Oral clefts generally have a multifactorial etiology. A number of genes contribute to the formation of the face and palate. Cleft lip and/or palate can occur in pedigrees with autosomal dominant holoprosencephaly due to mutations in Sonic Hedgehog (SHH). In addition, animal models have shown that SHH is involved in face development. We thus examined the human SHH gene in 220 newborn infants with nonsyndromic oral clefts registered by the Estudio Colaborativo Latinoamericano de Malformaciones Congenitas: ECLAMC (Latin American Collaborative Study of Congenital Malformations). We found 15 variant bands in 13 patients with oral clefts, representing five different base changes, all of which were found by sequencing to represent silent polymorphisms. Four occurred in introns. The alteration occurring in an exon, Ser190Ser, may create a consensus sequence for the 3′splice site 6 bp downstream of the original consensus sequence. Thus, we did not identify any clearly disease‐causing mutation in SHH in these patients, and conclude that SHH mutations are not a frequent cause of isolated oral clefts in humans. Published 2002 Wiley‐Liss, Inc.
Homozygous Gly530Ser substitution in COL5A1 causes mild classical Ehlers‐Danlos syndrome
Authors: Giunta C. , Nuytinck L. , Raghunath M. , Hausser I. , De Paepe A. , Steinmann B.
Published: August 2002

Skin hyperelasticity, tissue fragility with atrophic scars, and joint hypermobility are characteristic for the classical type of Ehlers‐Danlos syndrome (EDS). The disease is usually inherited as an autosomal dominant trait; however, recessive mode of inheritance has been documented in tenascin‐X‐deficient EDS patients. Mutations in the genes coding for collagen α1(V) chain (COL5A1), collagen α2(V) chain (COL5A2), tenascin‐X (TNX), and collagen α1(I) chain (COL1A1) have been characterized in patients with classical EDS, thus confirming the suspected genetic heterogeneity. Recently, we described a patient with severe classical EDS due to a Gly1489Glu substitution in the α1(V) triple‐helical domain who was, in addition, heterozygous for a disease‐modifying Gly530Ser substitution in the α1(V) NH2‐terminal domain [Giunta and Steinmann, 2000: Am. J. Med. Genet. 90:72–79; Steinmann and Giunta, 2000: Am. J. Med. Genet. 93:342]. Here, we report on a 4‐year‐old boy with mild classical EDS, born to healthy consanguineous Turkish parents; the mother presented a soft skin, while the father had a normal thick skin. Ultrastructural analysis of the dermis revealed in the patient the typical “cauliflower” collagen fibrils, while in both parents variable moderate aberrations were seen. Mutation revealed the presence of a homozygous Gly530Ser substitution in the α1(V) collagen chains in the patient, while both parents were heterozygous for the same substitution. An additional mutation in either the COL5A1 and COL5A2 genes was excluded. Furthermore, haplotype analysis with polymorphic microsatellite markers excluded linkage to the genes coding for α3(V) collagen (COL5A3), tenascin‐X (TNX), thrombospondin‐2 (THBS2), and decorin (DCN). These new findings support further our previous hypothesis that the heterozygous Gly530Ser substitution is disease modifying and now suggest that in the homozygous state it is disease causing. © 2002 Wiley‐Liss, Inc.
Carrier testing in fragile X syndrome: When to tell and test
Authors: McConkie‐Rosell Allyn , Spiridigliozzi Gail A. , Sullivan Jennifer A. , Dawson Deborah V. , Lachiewicz Ave M.
Published: August 2002

This study explored age preferences about when to learn at‐risk status and have carrier testing in women who were undergoing testing for fragile X. Forty‐two women (20 carriers and 22 noncarriers) completed a structured interview prior to carrier testing and after learning their result. The majority favored learning at‐risk status and carrier status at < 18 years for themselves and their children. Preferred ages fell into four developmental categories: early childhood (0–9), preteen (10–13), teen (14–17), and adult (≥ 18). Although no significant mean changes in age responses were found between interviews or between carrier and noncarrier responses, a difference in the pattern of responses related to age categories was suggested. There appeared to be an increase in the number of responses in the 0–9 category at time 2. Also, the mean ages for testing were older than they were for telling at time 1, but not at time 2. For women indicating ages 0–9, the most frequent reason was to provide children with time to adjust. Those reporting ages 10–13 felt that the onset of puberty as well as a child's ability to understand, adjust, and cope were key determinants. Those preferring the teen years felt the possibility of sexual activity and planning for the future were important considerations. The developmental focus for adults was serious relationships. This study, through its unique longitudinal perspective of transition from uncertainty to certainty, builds on prior knowledge, has implications for genetic counseling, and suggests that the developmental stage of the child is important in determining when to tell and test. © 2002 Wiley‐Liss, Inc.
No evidence of an association between 5HT1B receptor gene polymorphism and suicide victims in a Japanese population
Authors: Nishiguchi Naoki , Shirakawa Osamu , Ono Hisae , Nishimura Akiyoshi , Nushida Hideyuki , Ueno Yasuhiro , Maeda Kiyoshi
Published: August 2002

Serotonergic systems have been reported to mediate the control of aggression and/or impulsivity in humans and to be involved in suicidal behavior. Neurochemical studies showing serotonergic dysfunction in suicide appear to support the functional alteration of serotonergic systems due to gene polymorphisms. Knock‐out mice of the 5HT1B receptor gene have been reported to result in increased aggression. We hypothesized that the 5HT1B receptor‐mediated serotonergic dysfunction was implicated in suicide through disinhibition of aggression and/or impulsivity. To explore this hypothesis, we examined the association between suicide victims who completed suicide and the 5HT1B receptor gene G861C polymorphism. No significant differences in genotype distribution and allele frequencies were found between suicide victims and controls. Though there is the possibility of failing to detect small effects, these results show no evidence of an association between the 5HT1B receptor gene G861C polymorphism and suicide victims in a Japanese population and indicate that it is unlikely that the 5HT1B receptor is implicated in the susceptibility to suicide. © 2001 Wiley‐Liss, Inc.
Parental failure in captive cotton‐top tamarins (Saguinus Oedipus)
Authors: Bardi Massimo , Petto Andrew J. , Lee‐Parritz David E.
Published: August 2002

Several New World monkey species experience high rates of infant mortality in captivity, and parental failure in the form of infant neglect and abuse is often regarded as one of the leading causes of this problem. We explored a large archival database to assess environmental, familial, and biological variables identified as significant for parental success in previous studies of captive tamarins, through several generations and across several dozen pedigrees. Using a stepwise multiple regression analysis we developed a model including the fewest variables able to identify statistically significant predictors of infant outcome. We found that seven independent variables could predict infant outcome in the colony. The most important appeared to be the presence of helpers with whom parents could share infant carrying. Mother’s experience and litter size were two other variables that contributed to a significant extent to explaining parental failure. Moreover, the model showed that there is a measurable contribution to infant outcome due to the health status of both parents. Finally, we found a distinct role for mothers and fathers, and that parental failure follows different patterns for abuse and rejection. Am. J. Primatol. 54:159–169, 2001. © 2001 Wiley‐Liss, Inc.
Detection of antibodies to selected human pathogens among wild and pet macaques (Macaca tonkeana) in Sulawesi, Indonesia
Authors: Jones‐Engel Lisa , Engel Gregory A. , Schillaci Michael A. , Babo Rosnany , Froehlich Jeffery
Published: August 2002

Human‐to‐primate disease transmission can potentially cause significant morbidity and mortality among wild primate populations and thus constitutes an important conservation issue. Our cross‐sectional study examines serological evidence of exposure to human pathogens among wild and pet macaques in Sulawesi. Serum samples taken from 11 pet and 15 wild macaques (Macaca tonkeana) were analyzed for antibodies to a panel of viruses commonly encountered in human populations. Antibodies to measles, influenza A, and parainfluenza 1 were detected in sera of both pet and wild macaques. Antibodies to parainfluenza 2 and 3 were found in the sera of wild macaques only. Possible routes of exposure, as well as implications for conservation are discussed. Am. J. Primatol. 54:171–178, 2001. © 2001 Wiley‐Liss, Inc.
Mutation of the doublecortin gene in male patients with double cortex syndrome: Somatic mosaicism detected by hair root analysis
Authors: Kato Mitsuhiro , Kanai Masayo , Soma Osamu , Takusa Yuichi , Kimura Toshiyuki , Numakura Chikahiko , Matsuki Takasumi , Nakamura Shigeki , Hayasaka Kiyoshi
Published: August 2002

The molecular basis of double cortex syndrome was investigated in 2 male patients. Magnetic resonance imaging of the patients' heads showed diffuse subcortical band heterotopia, as is seen in female patients. We found a heterozygous mutation for Asp50Lys or Arg39Stop in both patients. Microsatellite polymorphism analysis revealed that both patients had inherited a single X chromosome from their mothers. Restriction enzyme analysis using DNA extracted from the hair roots of each patient showed four different patterns in the combination of cells carrying wild and mutant alleles, which strongly suggest somatic mosaicism. We conclude that somatic mosaic mutations in the doublecortin gene in male patients can cause subcortical band heterotopia, and that molecular analysis using hair roots is a useful method for detecting somatic mosaicism.
Hypoperfusion of Wernicke's area predicts severity of semantic deficit in acute stroke
Authors: Hillis Argye E. , Wityk Robert J. , Tuffiash Elizabeth , Beauchamp Norman J. , Jacobs Michael A. , Barker Peter B. , Selnes Ola A.
Published: August 2002

Based on earlier findings that the presence of word comprehension impairment (a deficit in the meaning of words, or lexical semantics) in acute stroke was strongly associated with the presence of hypoperfusion or infarct in Wernicke's area, we tested the hypothesis that the severity of word comprehension impairment was correlated with the magnitude of delay in perfusion of Wernicke's area on magnetic resonance perfusion‐weighted imaging. Eighty patients were prospectively studied within 24 hours of onset or progression of acute left hemisphere stroke symptoms, with diffusion‐weighted imaging, perfusion‐weighted imaging, and detailed language tests. For 50 patients without infarct in Wernicke's area, we found a strong Pearson correlation between the rate of errors on a word comprehension test and the mean number of seconds of delay in time‐to‐peak concentration of contrast in Wernicke's area, relative to the homologous region on the right. These results add further evidence for the crucial role of Wernicke's area (Brodmann's area 22) in word comprehension and indicate that the magnitude of delay on PWI may be a gross indicator of tissue dysfunction.
Synthesis of silver powder using a mechanochemical process
Authors: Keskinen J. , Ruuskanen P. , Karttunen M. , Hannula S.‐P.
Published: August 2002

Fine silver powder was synthesized in a mechanochemical process by inducing a solid‐state displacement reaction between AgCl and sodium. The process employed was ball milling in a planetary‐type ball mill. The reaction products were elemental silver and NaCl in powder form. The silver particles were separated out by washing the NaCl by‐product from the milled powder mixture. The milled powders were characterized using X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The XRD determination showed that the reaction between AgCl and sodium was complete in almost all the experiments carried out. In some cases a minor quantity of Ag2Na was formed. SEM and TEM examinations revealed that, depending on the milling parameters employed, the size of the particles in the synthesized metallic silver powder was in the range 50–1000 nm. Copyright © 2001 John Wiley & Sons, Ltd.
Arsenic in the prepared edible brown alga hijiki, Hizikia fusiforme
Authors: Hanaoka Ken'ichi , Yosida Kenta , Tamano Mie , Kuroiwa Takayoshi , Kaise Toshikazu , Maeda S.
Published: August 2002

To reduce the arsenic content of the leaves and branches of an edible brown alga, hijiki Hizikia fusiforme, the Japanese traditional washing and soaking process before cooking was shown to be effective: about 32 to 60% of the arsenic was removed from the alga at room temperature. Increasing the amount of water in which the hijiki was soaked did not affect arsenic removal. On the other hand, arsenic content decreased linearly as the temperature used to wash and soak hijiki increased from 0 to 60 °C. In the washed and soaked hijiki, inorganic arsenic accounts for 90% of the total arsenic and dimethylated arsenic compounds 10%. Copyright © 2001 John Wiley & Sons, Ltd.
Polycarbonate/polyalkylene terephthalate blends: Interphase interactions and impact strength
Authors: Pesetskii S. S. , Jurkowski B. , Koval V. N.
Published: August 2002

Blends of polycarbonate (PC) and poly(alkylene terephthalate) (PAT) such as poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) were investigated. It was learned that processes of phase separation in blends consisting of PC and PAT can cause variations in properties of both the amorphous and crystalline phases. In PC/PBT blends the DSC technique did not detect crystalline portion of PBT with its concentrations up to 20 wt %. For PBT = 40 wt %, it forms a continuous phase, and blend's crystallinity is close to the additive values. The glass transition temperature (Tg) shifts to the lower temperature region. The relaxation spectrometry revealed strong adhesion between phases in the blends over the temperature range from the completion of β‐transition to TgPAT. This interaction becomes weaker between TgPAT and TgPC. Temperature‐dependent variations in the molecular mobility and interphases interactions in the blends affect their impact strength. Over the temperature range where interphases interactions occur and the two components are in the glassy state, the blend is not impact resistant. Over the temperature range between TgPAT and TgPC the blends become impact‐resistant materials. This is because energy of crack propagation in the PAT amorphous phase—being in a high‐elastic state—dissipates. It is postulated that the effect of improving the impact strength of PC/PAT blends, which was found for temperatures between the glass transition temperatures of the mixed components, is also valid for other binary blends. © 2002 Wiley Perioodicals, Inc. J Appl Polym Sci 84: 1277–1285, 2002; DOI 10.1002/app.10472
High solids content emulsions. I. A study of the influence of the particle size distribution and polymer concentration on viscosity
Authors: Schneider M. , Claverie J. , Graillat C. , McKenna T. F.
Published: August 2002

An experimental and modeling study was carried out to understand the relationship between the viscosity of a multimodal latex and its particle‐size distribution (PSD) and polymer concentration. This study illustrates the inadequacy of existing models in predicting the viscosity of complex latices. It is shown that the latex viscosity at a fixed shear rate is very sensitive to the polymer concentration at high solids content and to the PSD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1878–1896, 2002; DOI 10.1002/app.10511
Preparation and characterization of cation exchangers from agricultural residues
Authors: Nada A. M. A. , Eid M. A. , El Bahnasawy R. M. , Khalifa M. N.
Published: August 2002

Cation‐exchange systems were prepared by phosphorylation of some lignocellulosic materials, namely, rice straw, cotton stalks, and bagasse. The effect of the particle size of the lignocellulosic materials as well as their chemical constituents on the phosphorylation process was studied by the determination of the phosphorus content of the prepared ion‐exchange material. Phosphorus was determined using inductively coupled plasma atomic emission spectrometry. Optimization of the phosphorylation reaction was achieved by studying the effect of the different experimental parameters, namely, the reaction time, temperature, and amount of phosphorus oxychloride added, on the phosphate content of the reaction product. The treatment of the lignocellulosic material with sodium hydroxide was found to improve its phosphorylation. The cation‐exchange efficiency of the produced phosphated material toward Cd2+, Co2+, Cr3+, Cu2+, Fe3+, Ni2+, Pb2+, and Zn2+ was examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 792–800, 2002
Hydrogenation of low molar mass OH‐telechelic polybutadienes catalyzed by homogeneous Ziegler nickel catalysts
Authors: Šabata S. , Hetflejš J.
Published: August 2002

Two types of low molar mass, medium vinylic polybutadienes containing 2‐hydroxypropyl and 2‐hydroxyethyl end groups were hydrogenated in the presence of several homogeneous Ziegler Ni catalysts prepared by using Ni(acac)2 and Ni(2‐ethylhexanoate)2 as metal precursors and BuLi, Li adduct to a diene and Et3Al as activators. The catalytic efficiency of these systems determined by rate measurements showed that the best results can be achieved with the Ni(2‐hexanoate)2 + Li‐diene (Ni : Li mol ratio = l : 8–10) catalyst in the solvents commonly used in the synthesis of these polyalkadienes by anionic polymerization of 1,3‐butadiene. As found by the kinetic study, the hydrogenation carried out under mild reaction conditions (temperatures of 10–35°C, hydrogen pressure of 72–178 kPa, Ni concentration of 2.1–10.0 mmol/dm−3) was the first order in the OH‐polybutadiene and hydrogen and, over narrow range of catalyst concentrations (4.3–10.0 mmol Ni/dm−3), also in the catalyst. The activation energy of the hydrogenation estimated from the Arrhenius plot was 42 kJ/mol. Changes in the relative proportion of 1,2‐, cis‐1,4‐, and trans‐1,4‐CC units of the polymer during hydrogenation indicate the selectivity of the catalyst to the 1,2‐hydrogenation. The ease of the addition of hydrogen to the internal CC unsaturation was found to be opposite to that usually observed (trans > cis). The present low‐pressure hydrogenation of both types of telechelic OH‐polybutadienes proceeds with full retention of the average OH functionality and affords the saturated polymers, the residual CC unsaturation of which (<1%) has so far been usually achieved by high‐pressure hydrogenations. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1185–1193, 2002
Preparation of semi‐interpenetrating polymer networks composed of silk fibroin and poly(ethylene glycol) macromer
Authors: Kweon H. Y. , Park S. H. , Yeo J. H. , Lee Y. W. , Cho C. S.
Published: August 2002

Semi‐interpenetrating polymer networks (SIPNs) composed of silk fibroin (SF) and a poly(ethylene glycol) (PEG) diacrylate macromer were synthesized and characterized. The conformation of SF in SIPNs was changed from a random coil to a β‐sheet structure by formation of SIPNs with PEG, while the crystalline structures of SF and PEG in SIPNs was not changed. The decomposition temperature of SF in the SIPNs was inner‐shifted, an indication of SIPN formation between the SF and the PEG macromer. The tensile strength and elongation of the SIPNs were much higher than were those of SF itself or the SF/PEG blend and increased with an increase of the PEG content. The equilibrium water content of SF was remarkably increased by formation of SIPNs with PEG due to the hydrophilic property of PEG. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1848–1853, 2001
Membrane transport of organics. III. Permeation of some carboxylic acids through bipolar polymer membrane
Authors: Wódzki Romuald , Nowaczyk Jacek
Published: August 2002

The permeation of acetic (AA), propionic (PA), lactic (LA), oxalic (OA), citric (CA), and tartaric (TA) acids through the bipolar ion‐exchange membrane Neosepta BP‐1 (Tokuyama Corp.) was studied. It was found that the fluxes (J, mol cm−2 s−1) and mass‐transfer coefficients (k, cm s−1) increase in the following order: CA < OA < LA < TA < PA ≤ AA. The transport processes in the Neosepta BP‐1 membrane are concentration‐dependent and can be described phenomenologically using I‐Fick's law for diffusion. The permeation phenomena correspond to the solution–diffusion model similarly as to the permeation of carboxylic acids through strongly acidic cation‐exchange membranes. However, in competitive AA–PA transport experiments, typically for strongly basic membranes, the separation ability of the BP‐1 membrane with a preference toward AA was observed. The selectivity coefficients α calculated as the ratio of the respective mass‐transfer coefficients vary in the range from 1.31 ± 0.2 to 2.1 ± 0.6. These values depend on the feed composition and the system arrangement, which means that α is always higher for the system with the anion‐exchange layer is in contact with a feed solution. Rather low fluxes of PA, AA, and other acids, as compared to some monopolar membranes (Neosepta AFN‐7, Nafion‐120, Flemion), are promising for the application of the bipolar membrane in an electrodialytic separation of carboxylic acids from their aqueous solutions or mixtures. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2705–2717, 2001
Processing and properties of thermoplastic starch and its blends with sodium alginate
Authors: Souza Roberta C. R. , Andrade Cristina T.
Published: August 2002

Viscosity measurements were carried out on corn starch (CS) and CS–sodium alginate (SA) suspensions at low levels of SA [1 to 10% (w/w)], as a function of temperature. The addition of SA caused the granular CS gelatinization process to occur at a lower onset temperature. CS and CS–SA mixtures were extruded in single‐ and twin‐screw extruders, with 15% glycerol and different water contents. Processing of plasticized CS–SA mixtures required lower temperatures, which is consistent with the viscosity results. Homogeneous and flexible extrudates were obtained by processing in a twin‐screw extruder. Samples in the composition range between 0 and 10% (w/w) SA were examined using tensile tests as a function of water content. Mechanical properties were dependent on the water content and on the SA composition. A significant increase in the Young's modulus value was observed for the blend containing 1% SA. Dynamic mechanical analysis was carried out for CS and CS–SA blends. Two transitions were detected in the temperature range –80 to 150°C. Scanning electron microscopy was used to examine the morphology of the extruded samples. The surfaces of the films were homogeneous, which demonstrated that the CS granules in all samples were characteristically destructured under the conditions used in processing. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 412–420, 2001
NR–EPDM covulcanization: A novel approach
Authors: Ghosh Arup Kumar , Debnath Subhas Chandra , Naskar Nityananda , Basu Dipak Kumar
Published: August 2002

Bis(diisopropyl)thiophosphoryl disulfide (DIPDIS) was used successfully as a novel coupling agent cum accelerator to co‐vulcanize the elastomer blend comprising highly unsaturated natural rubber (NR) and ethylene propylene diene rubber (EPDM) of low unsaturation content. The blend vulcanizates produced exhibit improved physical properties that can be further enhanced by implementing a two‐stage vulcanization technique, as well as by judicious selection of the NR‐to‐EPDM ratio. The results indicate coherency and homogeneity in the blend composition of two‐stage vulcanizates. The cure‐rate mismatch problem could thus be solved through the formation of rubber‐bound intermediates with a multifunctional rubber additive (i.e., DIPDIS), thereby restricting the curative migration from lower to highly unsaturated rubber. The blend morphology as revealed by SEM studies accounts for significant improvement in physical properties, particularly in two‐stage vulcanizates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 800–808, 2001
Mechanical properties of uncrosslinked and crosslinked linear low‐density polyethylene/wax blends
Authors: Krupa I. , Luyt A. S.
Published: August 2002

The mechanical properties of uncrosslinked and crosslinked linear low‐density polyethylene (LLDPE)/wax blends were investigated, using differential scanning calorimetry (DSC), tensile testing, and melt flow indexing. A decrease in the degree of crystallinity, as determined from the DSC melting enthalpies, was observed with an increase in the dicumyl peroxide (DCP) concentration. The Young's modulus increased with increased wax portions, and there was a higher increase for crosslinked blends. The yield stress generally decreased with increased peroxide content. Crosslinking caused an increase in elongation at yield, but increased wax content caused a decrease in elongation at yield. The stress at break generally increased with increasing peroxide content, but it decreased with increased wax content. The elongation at break decreased with an increase in the DCP concentration. Melt flow rate measurements indicated a mutual miscibility in LLDPE/wax blends. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 973–980, 2001
Thermal degradation behavior of epoxy resin blended with propyl ester phosphazene
Authors: Denq Bar‐Long , Chiu Wen‐Yen , Lin King‐Fu , Fuh Ming‐Ren Steve
Published: August 2002

The study was focused on the thermal degradation behavior of epoxy resins (EP) blended with propyl ester phosphazene (FR). The analysis studied the evolved gas and the residual char yield using different techniques. The results showed that pure epoxy resin and their blends were all a one‐stage thermal degradation reaction. The major degradation temperature of blends was lower than the temperature of pure epoxy resin, but the residual char yield of epoxy blends at 550°C was higher than that of pure epoxy resin. FR could accelerate the production of small molecules such as acetone, phenol, and isopropyl phenol during thermal degradation process. Honeycomb structure compounds were also formed in the residual char of epoxy and its blends. Additionally, elemental analysis of the residual char yield showed that phosphorus was a residual element, and other elements mostly diffused to the evolved gas. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1161–1174, 2001
Effect of diluents on membrane formation via thermally induced phase separation
Authors: Matsuyama Hideto , Teramoto Masaaki , Kudari Shunsuke , Kitamura Yoshiro
Published: August 2002

The effect of diluents on isotactic polypropylene (iPP) membrane formation via thermally induced phase separation was investigated. The diluents were methyl salicylate (MS), diphenyl ether (DPE), and diphenylmethane (DPM). The cloud‐point curve was shifted to a lower temperature in the order iPP–MS, iPP–DPE, and iPP–DPM, whereas the crystallization temperature was not influenced so much by diluent type. Droplet‐growth processes were investigated under two conditions: quenching the polymer solution at the desired temperature and cooling at a constant rate. Although droplet sizes were in the order iPP–MS, iPP–DPE, and iPP–DPM in both cases, the difference was more pronounced with the constant cooling rate condition. Scanning electron microscopy indicated that interconnected structures were obtained when the polymer solution was quenched in ice water. The effect of the diluents on these structures was observed. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 169–177, 2001
Elasticity of ion‐exchange resin beads in solvent mixtures
Authors: Tiihonen Jari , Markkanen Ismo , Laatikainen Markku , Paatero Erkki
Published: August 2002

The effect of the solvent composition on the elasticity of strong and weak cation‐ and anion‐exchange resin beads was studied. Poly(styrene‐co‐divinylbenzene) resins containing sulfonic acid or quaternary ammonium groups and an acrylic acid resin crosslinked with divinylbenzene were immersed in water, NaCl solutions, or aqueous alcohol solutions and the shear modulus was measured with a uniaxial compression method. The elastic data were compared with the swelling properties. In pure water the shear moduli increased when the crosslink density, counterion valence, counterion size, and functional group size increased. Two additional phenomena in the elastic behavior were observed when the swelling degree of the resins was changed by the addition of alcohol or salt. A decrease of the modulus was observed when moving from the fully swollen state to a less swollen state, and a steep upturn of the modulus took place at a characteristic swelling region. The depth of the minimum and the location of the transition from the rubbery to the glassy state depended on the characteristics of the resins. The finite expansibility of the polymer chains and the glass transition explained these findings. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1256–1264, 2001
Thermal and dynamic mechanical behavior of ethylene/norbornene copolymers with medium norbornene contents
Authors: Forsyth John F. , Scrivani Teresa , Benavente Rosario , Marestin Catherine , Pereña José M.
Published: August 2002

A range of ethylene/norbornene copolymers were synthesized using the commercially available rac‐Et(Ind)2ZrCl2 metallocene catalyst. A large window of norbornene contents, between 30 and 55 mol % was used to facilitate the interpretation of the results. The polymers were characterized by means of wide‐angle X‐ray scattering, differential scanning calorimetry, and dynamic mechanical thermal analysis. The X‐ray diffractograms showed two amorphous halos, the low‐angle one increasing in the intensity with norbornene content. Calorimetric and dynamic mechanical results led to a linear relation between the glass transition temperature and the norbornene content. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2159–2165, 2001
Characterization and structural modification of ammonic lignosulfonate by methylolation
Authors: Alonso M. V. , Rodríguez J. J. , Oliet M. , Rodríguez F. , García J. , Gilarranz M. A.
Published: August 2002

The methylolation of softwood and hardwood lignosulfonates was studied. Six different lignosulfonate samples (three from hardwoods and three from softwoods) were characterized in order to assess their suitability for methylolation. The techniques employed in characterization were UV/vis spectroscopy, Fourier transform infrared (FTIR), and 1H‐nuclear magnetic resonance (1H‐NMR). The best properties were shown by softwood ammonium lignosulfonate (LAS), which was used to optimize the operation conditions to promote the Lederer–Manasse reaction. The methylolation variables studied were the sodium hydroxide‐to‐lignin molar ratio, the formaldehyde‐to‐lignin molar ratio, time, and temperature. The reaction was followed by the changes in the concentration of free formaldehyde. IR and NMR spectra of nonmodified and modified samples were used to study the structural changes. Under optimum operation conditions, softwood lignosulfonates showed higher reactivity toward formaldehyde than did hardwood lignosulfonates. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2661–2668, 2001
Surface modification of poly(tetrafluoroethylene) with pulsed hydrogen plasma
Authors: Inagaki N. , Tasaka S. , Narushima K. , Teranishi K.
Published: August 2002

Surface modification of polymers by pulsed plasma has been investigated to minimize degradation reactions occurring at the same time as the surface modification reactions. The hydrogen radical, ion, and electron concentrations in the hydrogen plasma were simulated as a function of the elapsed time after turning off the discharge. The contact angle measurement showed that hydrogen plasma treatment, regardless of pulsed or continuous plasma, led to degradation reactions as well as defluorination and oxidation on PTFE surfaces. The degradation reactions of PTFE chains initiated by the pulsed hydrogen plasma were not as vigorous as those by the continuous hydrogen plasma. A combination of the on‐time/off‐time of 30/270μs in the pulsed hydrogen plasma was efficacious in modifying PTFE surfaces. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 340–348, 2002