bluuebunny/crossref_metadata_2025 huggingface dataset:
Hypersensitivity and idiosyncratic reactions to oxaliplatin
Authors: Thomas Rebecca R. , Quinn Mary G. , Schuler Barbara , Grem Jean L.
Published: April 2003

BACKGROUND

Oxaliplatin is a third‐generation platinum analog that is used to treat a variety of solid tumors, particularly colorectal carcinoma. Patients may develop hypersensitivity reactions, although this complication occurs infrequently.

METHODS

Three patients developed hypersensitivity reactions to oxaliplatin while undergoing treatment on a Phase I trial of oxaliplatin and capecitabine. An Entrez PUBMED search was performed to identify other cases.

RESULTS

Two patients experienced the abrupt onset of erythema alone or with pruritis during the 9th and 11th infusions of oxaliplatin, whereas the other patient developed fever and mild dyspnea a few hours after the 9th oxaliplatin infusion. All 3 patients were rechallenged successfully for at least 1 additional oxaliplatin infusion by using oral dexamethasone, 20 mg orally, 6 and 12 hours before the administration of oxaliplatin and by administering intravenously 125 mg of solumedrol, 50 mg of diphenhydramine, and 50 mg of cimetidine 30 minutes before oxaliplatin. The literature review suggests two distinct patterns of reactions: classic hypersensitivity (as experienced by the first two patients) and idiosyncratic reactions (as experienced by the third patient).

CONCLUSIONS

Patients who develop mild to moderate hypersensitivity to oxaliplatin may be pretreated with steroids and antagonists of Type 1 and 2 histamine receptors, whereas patients who develop severe reactions are unlikely to tolerate further therapy. Cancer 2003;97:2301–7. Published 2003 American Cancer Society.

DOI 10.1002/cncr.11379
New method to measure control performance of dust palliatives on unpaved roads at federal facilities
Authors: Muleski Gregory E. , Trenholm Andrew R. , Gebhart Dick L. , Franke Deborah L. , Cowherd Chatten
Published: April 2003

Military training activities often produce significant dust emissions from unpaved travel surfaces. Because
failure to comply with environmental regulations could adversely affect training operations, prudent use of
chemical palliatives for control of dust from unpaved surfaces enhances the Army's land‐based training
capability, mission, and combat readiness.

This article describes a new, more efficient method to determine the control effectiveness of palliatives on
roads at Army facilities. Rather than attempting to quantify “absolute” emission rates, the
“mobile sampler” described in this article relies on relative measures. As compared to the methods
used in previous field studies, the mobile sampler is not only more efficient in terms of time and labor required,
it also provides greater reproducibility and relieves many of the restrictions placed on acceptable test sites
when using test methods for absolute emission levels. © 2003 Wiley Periodicals, Inc.
Individual job‐choice decisions and the impact of job attributes and recruitment practices: A longitudinal field study
Authors: Boswell Wendy R. , Roehling Mark V. , LePine Marcie A. , Moynihan Lisa M.
Published: April 2003

The present research is intended to contribute to the understanding of how job‐choice decisions are
made and the role of effective and ineffective recruiting practices in that
process. The issues are examined by tracking job seekers through the job search and choice process. At multiple
points in the process, structured interviews are used to elicit information from the job seekers pertaining to
how they are making their decision and what factors play a role. Results provide theoretical and practical
insights into the organizational and job attributes important to job choice, as well as how specific recruiting
practices may exert a significant influence, positive or negative, on job‐choice decisions. For example,
our findings reinforced the importance of providing job seekers the opportunity to meet with multiple (and
high‐level) organizational constituents, impressive site‐visit arrangements, and frequent and
prompt follow‐up. Also, imposing a deadline (i.e., “exploding offer”) showed little
effect on job‐choice decisions. Recommendations for recruitment practice and continued research are
provided. © 2003 Wiley Periodicals, Inc.
Time and space: Reframing the training and development agenda
Authors: Baird Lloyd , Griffin Darrell , Henderson John
Published: April 2003

In this article, we review how time and space relationships are reframing the training and development agenda.
As the speed of business moves faster and boundaries become less relevant, we need ways of expanding and choosing
how and when learning and development can take place. We need ways to target development on specific business
issues and deliver improved performance in less time with reduced cost. We define a learning options framework to
help organize, integrate, synthesize, and better fit training and development methodologies to business realities.
Specific knowledge, tools, and examples are provided to show how organizations are identifying and choosing among
development options. © 2003 Wiley Periodicals, Inc.
Clusters of chromosomal imbalances in thymic epithelial tumours are associated with the WHO classification and the staging system according to Masaoka
Authors: Penzel Roland , Hoegel Josef , Schmitz Waltraud , Blaeker Hendrik , Morresi‐Hauf Alicia , Aulmann Sebastian , Hecker Erich , Mechtersheimer Gunhild , Otto Herwart F. , Rieker Ralf J.
Published: April 2003

Using comparative genomic hybridisation, we investigated chromosomal imbalances in 28 cases of thymic epithelial neoplasms including type A, B2, B3, the A component of type AB and different subtypes of type C thymoma. To identify different patterns of chromosomal aberrations associated with the biological behaviour and the histological diversity of thymomas, a hierarchical cluster analysis of 65 cases was performed. The here‐reported Comparative Genomic Hybridisation (CGH) data (28 cases) of partly uninvestigated tumour subtypes were pooled with previously published data of chromosomal imbalances of 37 thymomas (Zettl et al. [Am J Pathol 2000;157:257–66]). The analysis of 278 chromosomal subbands yielded 2 main clusters. The first main cluster was characterised by gains of the chromosomal arm 1q, consisted only of type C and B3 thymomas and was further subdivided into 2 subgroups. To the first subgroup only thymomas were attributed, which, in addition to gains of the chromosomal arm 1q, showed losses on 6q and 16q, whereas tumours belonging to the second subgroup exhibited no further recurrent chromosomal alterations. The second main cluster was formed by a heterogeneous group of thymoma types (types A, AB, B2, B3 and C), showing no specific pattern of chromosomal imbalances. In 19 thymomas, no chromosomal imbalances could be detected (3 type B2 and 5 type A thymomas of our study as well as 11 type A thymomas investigated by Zettl et al., Am J Pathol 2000;157:257–66). Chromosomal imbalances were more frequent in type C thymomas than in other subtypes. The distribution of tumour stages according to Masaoka (p = 0.003) and the World Health Organisation (WHO) classification (p < 0.0001) was significantly different in the clusters and subgroups obtained. The groups reflect the staging system and the WHO classification and show that type B3 and type C carcinomas have a strong relationship concerning their chromosomal imbalances. Furthermore, chromosomal imbalances detected in some type A thymomas might be responsible for the aggressive behaviour described in a few cases of this thymoma subtype. © 2003 Wiley‐Liss, Inc.
Vascular endothelial growth factor‐A determines detectability of experimental melanoma brain metastasis in GD‐DTPA‐enhanced MRI.
Authors: Leenders William , Küsters Benno , Pikkemaat Jeroen , Wesseling Pieter , Ruiter Dirk , Heerschap Arend , Barentsz Jelle , de Waal Robert MW
Published: April 2003

We have previously shown that the dense vascular network in mouse brain allows for growth of human melanoma xenografts (Mel57) by co‐option of preexisting vessels. Overexpression of recombinant vascular endothelial growth factor‐A (VEGF‐A) by such xenografts induced functional and morphologic alterations of preexisting vessels. We now describe the effects of VEGF‐A expression on visualization of these brain tumors in mice by magnetic resonance imaging (MRI), using gadolinium diethylenetriaminepenta‐acetic acid (Gd‐DTPA) and ultra small paramagnetic iron oxide particles (USPIO) as contrast agents. Brain lesions derived from (mock‐transfected) Mel57 cells were undetectable in MRI after Gd‐DTPA injection. However, the majority of such lesions became visible after injection of USPIO, due to the lower vascular density in the lesions as compared to the surrounding parenchyma. In contrast, VEGF‐A‐expressing lesions were visualized using Gd‐DTPA‐enhanced MRI by a rapid circumferential enhancement, due to leaky peritumoral vasculature. USPIO‐enhanced MRI of these tumors corroborated the immunohistochemic finding that peritumorally located, highly irregular and dilated vessels were present, while intratumoral vessel density was low. Our study shows that VEGF‐A is a key factor in imaging of brain neoplasms. Our data also demonstrate that, at least in brain, blood‐pool agent‐enhanced MRI may be a valuable diagnostic tool to detect malignancies that are not visible on Gd‐DTPA‐enhanced MRI. Furthermore, the involvement of VEGF‐A in MRI visibility suggests that care must be taken with MRI‐based evaluation of antiangiogenic therapy, as anti‐VEGF treatment might revert a tumor to a co‐opting phenotype, resulting in loss of contrast enhancement in MRI. © 2003 Wiley‐Liss, Inc.
Effect of the surface charge of liposomes on their uptake by angiogenic tumor vessels
Authors: Krasnici Senat , Werner Alexander , Eichhorn Martin E. , Schmitt‐Sody Marcus , Pahernik Sascha A. , Sauer Birgitta , Schulze Brita , Teifel Michael , Michaelis Uwe , Naujoks Kurt , Dellian Marc
Published: April 2003

Recently, cationic liposomes have been shown to preferentially target the angiogenic endothelium of tumors. It was the aim of our study to investigate the influence of liposomal surface charge on the uptake and kinetics of liposomes into solid tumors and tumor vasculature. Experiments were performed in the amelanotic hamster melanoma A‐Mel‐3 growing in the dorsal skinfold chamber preparation of male Syrian golden hamsters. Fluorescently labeled liposomes with different surface charge were prepared. Accumulation of i.v. injected liposomes was assessed by quantitative intravital fluorescence microscopy of tumor and surrounding host tissue. The histological distribution of liposomes was analyzed by double‐fluorescence microscopy 20 min after application of fluorescently labeled lectin as a vascular marker. After i.v. application of anionic and neutral liposomes, we observed an almost homogeneous distribution of liposome‐induced fluorescence throughout the chamber preparation without specific targeting to tumor tissue. In contrast, cationic liposomes exhibited a significantly enhanced accumulation in tumor tissue and tumor vasculature up to 3‐fold compared to surrounding tissue (p<0.05). The histological distribution of neutral and anionic liposomes revealed extravasation 20 min after i.v. injection, while cationic liposomes displayed a highly selective accumulation on the vascular endothelium. In conclusion, cationic liposomes exhibited a preferential uptake in angiogenic tumor vessels and therefore may provide an efficient tool for the selective delivery of diagnostic or therapeutic agents to angiogenic blood vessels of solid tumors. On the other hand, anionic and neutral liposomes may be used as carriers of drugs to the extravascular compartment of tumors due to their extravasation. © 2003 Wiley‐Liss, Inc.
Differential expression of hMLH1 and hMSH2 is related to bladder cancer grade, stage and prognosis but not microsatellite instability
Authors: Catto James W. F. , Xinarianos George , Burton Julian L. , Meuth Mark , Hamdy Freddie C.
Published: April 2003

Defects in the DNA mismatch repair proteins result in microsatellite instability and malignancy in hereditary non‐polyposis colorectal carcinoma (HNPCC). However, the role of mismatch repair (MMR) proteins and microsatellite instability (MSI) in transitional cell carcinoma of the bladder is less clear. In our study, the expression of 2 MMR proteins and the frequency of MSI in Transitional cell carcinoma of the bladder (TCC) were investigated. One hundred eleven patients with TCC of the bladder were studied, with complete clinicopathological data (median follow up of 5 years, range 5–16 years). Immunohistochemistry was used to detect the expression levels of hMLH1 and hMSH2. Microsatellite analysis for 14 loci (10 loci from the Bethesda consensus panel and the repeats in the TGFβR2, BAX, hMSH3 and hMSH6 genes) was performed on 84 tumors. Reduced expression of either MMR protein was seen in 26 of 111 tumors (23%). Reduced expression was seen more commonly in muscle invasive (p<0.03) and high grade TCC (p<0.03) than in superficial, low grade tumors. By 5 years, reduced expression of either MMR protein was associated with fewer recurrences of superficial tumors (p=0.015) and fewer relapses in all tumors (p=0.03), compared to tumors with normal expression. Nine tumors had reduced expression of both MMR proteins, analysis which suggests a synergistic reduction in expression (p=0.001). MMR expression was related to patient age, younger patients being more likely to have reduced MMR expression than older patients (p<0.01). MSI was seen at multiple loci in 1 tumor (1%) and at a single locus in 6 tumors (7%). MSI was not associated with MMR expression. Our findings indicate that reduced expression of the MMR proteins may have an important contribution in the development of a subset of TCCs and suggest a potential role for MMR expression as prognostic indicators. © 2003 Wiley‐Liss, Inc.
Influence of tumor location on breast cancer prognosis
Authors: Kroman Niels , Wohlfahrt Jan , Mouridsen Henning T. , Melbye Mads
Published: April 2003

Our objective was to investigate the influence of primary tumor location on breast cancer prognosis. We used a population‐based registry since 1977 that has collected detailed information regarding clinical and histopathological presentation, postoperative therapy and follow‐up status on Danish women with breast cancer. Nodal status and relative risk of dying was estimated according to primary tumor localization in the breast. Overall, 35,319 patients with primary breast cancer were included in the study. After adjustment for prognostic factors, the risk of dying increased significantly (up to 21%) with increasing distance of tumor location from the axilla. This trend was seen both among women with and without spread to the axillary lymph nodes. In conclusion, survival is significantly better for women with a tumor in the upper lateral quadrant than tumors located elsewhere in the breast. Our finding of a similar trend according to distance from the axilla among women with positive axillary lymph nodes who all are allocated to systemic therapy suggests that a better lymph node staging procedure alone is unlikely to eliminate these survival differences. Other reasons for the observed differences should be sought to help improve survival for women with breast cancer. © 2003 Wiley‐Liss, Inc.
Molecular detection of p16 promoter methylation in the serum of recurrent colorectal cancer patients
Authors: Nakayama Hiroshi , Hibi Kenji , Takase Tsunenobu , Yamazaki Taiji , Kasai Yasushi , Ito Katsuki , Akiyama Seiji , Nakao Akimasa
Published: April 2003

We previously proved that p16 promoter methylation present in the tumors of colorectal cancer patients can be detected in the serum of those same patients using methylation‐specific PCR (MSP). To seek the possibility that this technique could be applied to the monitoring of cancer recurrence, we examined the p16 methylation using MSP. We detected tumor DNA in the serum of 31 of 45 (69%) patients with recurrent colorectal cancer. No methylation was found in serum DNA of 50 patients with colorectal cancers whose corresponding tumor DNA had no methylation in p16 promoter. These results suggested that MSP might be a sensitive and useful method to detect recurrent colorectal cancer in serum. © 2003 Wiley‐Liss, Inc.
Fried potatoes and human cancer
Authors: Pelucchi Claudio , Franceschi Silvia , Levi Fabio , Trichopoulos Dimitrios , Bosetti Cristina , Negri Eva , La Vecchia Carlo
Published: April 2003

A considerable public concern about cancer risk from acrylamide‐rich foods followed the announcement that high concentrations of acrylamide are found in fried potatoes and potato chips and, more generally, in starch‐containing foods cooked at high temperatures. From a series of hospital‐based case–control studies conducted in Italy and Switzerland between 1991 and 2000, we have analyzed the relation between intake of fried/baked potatoes and cancer risk. The cancer sites considered were oral cavity and pharynx (749 cases, 1,772 controls), esophagus (395 cases, 1,066 controls), larynx (527 cases, 1,297 controls), large bowel (1,225 colon and 728 rectum cases, 4,154 controls), breast (2,569 cases, 2,588 controls) and ovary (1,031 cases, 2,411 controls). All cancer cases were incident and histologically confirmed. Controls were subjects admitted to the same network of hospitals of cases for acute, non‐neoplastic conditions. All the odds ratios (OR) for the highest vs. the lowest tertile of intake ranged between 0.8–1.1. We found no evidence of interaction with age, gender, alcohol and tobacco use. Our data provide reassuring evidence for the lack of an important association between consumption of fried/baked potatoes and cancer risk. © 2003 Wiley‐Liss, Inc.
Leucine‐zipper protein, LDOC1, inhibits NF‐κB activation and sensitizes pancreatic cancer cells to apoptosis
Authors: Nagasaki Koichi , Schem Christian , von Kaisenberg Constantin , Biallek Marco , Rösel Frank , Jonat Walter , Maass Nicolai
Published: April 2003

We have isolated a novel gene, LDOC1, which encodes for a leucine zipper protein that was downregulated in a series of human pancreatic cancer cell lines but was expressed in corresponding normal tissues. We report the initial characterization of LDOC1 as a novel regulator of the transcriptional response mediated by the nuclear factor kappa B (NF‐κB). Transient expression of LDOC1 significantly inhibited the luciferase activity in LDOC1‐negative BxPC‐3 pancreatic cancer cell line transfected with the NF‐κB reporter plasmid, activated with mitogen‐activated protein kinase/ERK kinase kinase‐1 (MEEK). LDOC1, however, does not affect p53, AP1 and CRE‐dependent reporter gene expression. The activation of NF‐κB through ligand‐induced stimulation by tumor necrosis factor‐α (TNF‐α) or phorbol 12‐myristate 13‐acetate (PMA) was also inhibited by transient expression of LDOC1 in a dose dependent manner. To determine the growth effect of LDOC1 expression on cancer cells, BxPC‐3 cells were stably transfected with LDOC1 cDNA. Viability studies demonstrated that TNF‐α or PMA‐induced antiproliferative effects were significantly enhanced by stable transfection of cells with LDOC1. These observations suggest that LDOC1 is a novel regulator of NF‐κB that can affect the PMA or TNF‐α‐mediated pathway to apoptosis through inhibition of NF‐κB activation in BxPC3 pancreatic cancer cells. © 2003 Wiley‐Liss, Inc.
Increased protein expression of DNA methyltransferase (DNMT) 1 is significantly correlated with the malignant potential and poor prognosis of human hepatocellular carcinomas
Authors: Saito Yoshimasa , Kanai Yae , Nakagawa Tohru , Sakamoto Michiie , Saito Hidetsugu , Ishii Hiromasa , Hirohashi Setsuo
Published: April 2003

Alteration of DNA methylation is one of the most consistent epigenetic changes in human cancers. DNA methyltransferase (DNMT) 1 is a major enzyme involved in establishing genomic methylation patterns. Most of the studies concerning DNMT1 expression in human cancers have been performed only at the mRNA level. To directly examine DNMT1 protein expression levels during human hepatocarcinogenesis, 16 histologically normal liver tissues, 51 noncancerous liver tissues exhibiting chronic hepatitis or cirrhosis, which are considered to be precancerous conditions, and 53 hepatocellular carcinomas (HCCs) were subjected to immunohistochemic examination. If more than 20% of the cells exhibited nuclear DNMT1 staining, the tissue sample was considered to be DNMT1‐positive. DNMT1 immunoreactivity was observed in 23 (43%) of the HCCs, but in none (0%) of the histologically normal liver or noncancerous liver tissues exhibiting chronic hepatitis or cirrhosis. The incidence of increased DNMT1 protein expression in HCCs correlated significantly with poor tumor differentiation (p = 0.0006) and portal vein involvement (p = 0.0002). Moreover, the recurrence‐free (p = 0.0001) and overall (p < 0.0001) survival rates of patients with HCCs exhibiting increased DNMT1 protein expression were significantly lower than those of patients with HCCs that did not exhibit increased expression. Increased DNMT1 protein expression may play a critical role in the malignant progression of HCCs and be a biologic predictor of both HCC recurrence and a poor prognosis in HCC patients. © 2003 Wiley‐Liss, Inc.
Chords of longest circuits of graphs embedded in torus and Klein bottle
Authors: Li Xuechao , Zhang Cun‐Quan
Published: April 2003

Thomassen conjectured that every longest circuit of a 3‐connected graph has a chord. It is proved in this paper that every longest circuit of a 4‐connected graph embedded in a torus or Klein bottle has a chord. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 1–23, 2003
Highly edge‐connected detachments of graphs and digraphs
Authors: Berg Alex R. , Jackson Bill , Jordán Tibor
Published: April 2003

Let G = (V,E) be a graph or digraph and r : V → Z+. An r‐detachment of G is a graph H obtained by ‘splitting’ each vertex ν ∈ V into r(ν) vertices. The vertices ν1,…,νr(ν) obtained by splitting ν are called the pieces of ν in H. Every edge uν ∈ E corresponds to an edge of H connecting some piece of u to some piece of ν. Crispin Nash‐Williams 9 gave necessary and sufficient conditions for a graph to have a k‐edge‐connected r‐detachment. He also solved the version where the degrees of all the pieces are specified. In this paper, we solve the same problems for directed graphs. We also give a simple and self‐contained new proof for the undirected result. © 2003 Wiley Periodicals, Inc. J Graph Theory 43: 67–77, 2003
Kinetics of crystallization and a crystal‐crystal transition in poly‐1‐butene
Authors: Boor J. , Mitchell J. C.
Published: April 2003

The formation and melting of the two crystalline modifications of poly‐1‐butene have been studied by the techniques of differential thermal analysis, infrared spectroscopy, dilatometry, and polarizing microscopy. On cooling the melt, modification 2 (Tm = 120–126°C.) appears within minutes. This form is unstable and gradually transforms to modification 1 (Tm = 135–142°C.). A density change of over 4% accompanies this latter transformation. As torsional damping experiments have shown the amorphous content to decrease by only about 5%, the stable modification must be much more dense than the unstable form. The kinetics of the crystallization of modification 2 from the melt were studied primarily dilatometrically at several temperatures. The data generally followed the Avrami equation with n equal to 4. This crystallization shows a high negative temperature coefficient (T1/2 = 380 min. at 110°C. and 2 min. at 90°C.) and becomes too rapid to measure by this technique at lower temperatures. The kinetics of the transformation of modification 2 to modification 1 were followed in infrared spectral, density gradient tube, and dilatometric studies. At room temperature, halftimes ranging from 250 to 1600 min. were observed, depending on the mechanical and thermal history of the sample. The observed discrepancies have been shown to be due, at least in part, to orientation effects. In dilatometric studies of the temperature dependence, the transition rate showed a pronounced maximum in the region of 15°C. Large increases in the torsional modulus and offset yield point of the specimen were observed to accompany the transition.
The dielectric relaxation time spectrum and the corresponding cole‐cole diagram for methylcellulose in water
Authors: Kuhn W. , Moser P.
Published: April 2003

From a measurement of the dielectric increment of methylcellulose in water, including the frequency dependence of this increment, the dielectric relaxation time spectrum has been determined and represented quantitatively by a formula containing three parameters τor, νAh, and θq, each of which can be obtained from earlier published viscosity and birefringence of flow data. On the basis of this relaxation time spectrum, the Cole‐Cole diagram of the aqueous solution of methylcellulose can be drawn. It is found that this diagram is dissymmetrical, i.e., different in shape from a circle or part of a circle; the circular form of the Cole‐Cole diagram is thus not a general phenomenon, even if it is realized in many cases.
Viscosity of critical mixtures
Authors: Debye P. , Chu B. , Woermann D.
Published: April 2003

Measurements of the viscosity of critical mixtures were extended to high polymer solutions (polystyrene–cyclohexane). An anomaly is found in the temperature coefficient of the viscosity. An empirical expression for the viscosities of critical mixtures as a function of ΔT/Tc, where ΔT = T − Tc, and Tc is the critical temperature, is derived.
Critical opalescence of polystyrene in ethylcyclohexane
Authors: Debye P. , Woermann D. , Chu B.
Published: April 2003

The range of molecular forces and the critical temperature of polystyrene in ethylcyclohexane are calculated from measurements of the angular dependence of critical opalescence. The polystyrene samples have molecular weights ranging from 69,000 to 552,000. The range of molecular forces remains strikingly small and is comparable with values obtained earlier on the system polystyrene–cyclohexane.
A theory for surface elevation in the weissenberg effect
Authors: Middleman Stanley
Published: April 2003

A Couette flow generated by a cylinder rotating perpendicular to the free surface of a fluid is considered and the equations of motion are solved to yield an expression for the surface shape in the vicinity of the rod. The fluid model chosen is one for which the shear stress τrθ and the normal stresses Trr and Tee obey the relations

where M, n, a, b, and κ are constants characteristic of the fluid and v is the flow velocity component in the angular direction. The results are found to be in reasonable agreement with previous experimental observations of the Weissenberg effect.
Depolarization of scattered light in solutions of linear and branched polysaccharides
Authors: Rao V. S. R. , Foster Joseph F.
Published: April 2003

The effect of branching on the depolarization of light scattered from polymer solutions has been investigated employing various branched and unbranched polysaccharides. Two dextran fractions of M̄w 71,000 and 131 × 106 were studied in a strong solvent (aqueous KOH) and an indifferent solvent (water). The other polymers, studied in aqueous KOH only, included unfractionated corn amylopectin, the β‐amylase limit dextrin of corn amylopectin, unfractionated corn amylose, and three subfractions of potato amylose (M̄w = 2.4 × 106, 1.14 × 106, and 0.27 × 106). Each polymer system was studied at several concentrations and all components of the scattered light, namely Hu, Vu, Hv, Vv, Hk, and Vh, were measured in each case. In general the results are in agreement with predictions of Krishnan and of Doty. However, certain important deviations from predicted behavior are noted and discussed.
Unsaturation in high impact polystyrene analytical studies
Authors: Crompton T. R. , Reid V. W.
Published: April 2003

A method for separating a pure gel and a soluble graft containing fraction from high impact polystyrene is described together with methods for determining the unsaturation of these two fractions and for the determination of unsaturation in polybutadiene rubber and unfractionated high impact polystyrene samples. The methods have been used to show how the rubber distributes between the gel and soluble fractions obtained from high impact polystyrenes prepared by the interpolymerization technique.
Depolarization measurements of polymer solutions in high dilutions. Part I
Authors: Kalpagam V. , Ramakrishna Rao M.
Published: April 2003

The depolarization ratios of unpolarized light, vertically polarized light, and horizontally polarized light at 90° have been measured for polyvinyl acetate solutions at high dilutions with the help of a specially designed differential amplifier. Over the concentration range (0.01–0.25%) studied, the values of ρu and ρv decrease sharply with increasing concentrations up to a concentration of about 0.1% and then the curves flatten out. Depending upon the nature of the solvent, there exists for each polymer—solvent system a critical concentration range above which the anisotropy of the molecules does not later further. This behavior is the same both in the good solvent (methyl ethyl ketone) and the relatively poor solvent (ethyl acetate). The experimentally determined ρh values generally are in agreement with the values calculated from the reciprocity theorem, except where ρh values are greater than one. In the case of ρh values which are greater than unity the difference between the experimentally determined and the calculated values is as high as 70%.
Nitroso fluorocarbon elastomers. Polymerization mechanism
Authors: Crawford G. H. , Rice D. E. , Landrum B. F.
Published: April 2003

The mechanism of copolymerization of fluoronitrosoalkanes with fluoroolefins was investigated. The reaction was not inhibited by water or other common ionic polymerization inhibitors but was greatly affected by free radicals or radical chain transfer agents, indicating a free radical polymerization mechanism. Evidence against initiation by impurities or by homolytic cleavage of the nitroso monomer was obtained. Initial rates of polymerization in solution were determined. The data obtained is consistent with a polymerization mechanism involving initiation by a radical formed through the interaction of the fluoroolefin with the fluoronitrosoalkane which has a significant diradical or triplet state population at the polymerization temperature. The reactivities of various monomers, the formation of low molecular weight product and the structures of the oxazetidine by‐products are discussed in terms of this mechanism.
Particle size distribution in polymer solutions
Authors: Maurer John J.
Published: April 2003

Log‐normal particle size distributions in polymer solutions have been measured with the Coulter counter. Qualitative membrane diffusion measurements were performed to substantiate the presence in these solutions of particles in the micron size range. Particle size was found to be dependent upon the thermal history of a polymer solution and upon the shearing forces to which it had been subjected. Further, particle size decreased upon dilution of a polyelectrolyte solution or upon an increase in the salt content. It is concluded that polymeric aggregates are the species being counted. These aggregates apparently originated during the polymerization of the polystyrene or of the styrene maleic anhydride studied. Bimodal distributions were observed in polystyrene solutions and in polystyrene sulfonate (Na+) solutions. The latter bimodal systems were resolved by graphical means, and it was found that the two populations are present in the ratio 65:35. The two distributions have the same dispersions (0.04) and only slightly different means (3.7 versus 4.5 microns). The mechanism of formation of this bimodal system may be that proposed by van der Hoff; namely, that particles are formed consecutively in the micellar and in the aqueous phase of an emulsion polymerization system when the soap concentration is near the critical micelle concentration.
Crystallinity and the structure of celluloses
Authors: Heritage K. J. , Mann J. , Roldan‐Gonzalez L.
Published: April 2003

Observations on the x‐ray scattering by ball‐milled cellulose and cellulose derivatives, amorphous oligosaccharides, and Fortisan H are reported and an approximate shape is established for the scattering curve of the noncrystalline component of celluloses. Using this shape measurements have been made of the minimum crystallinity which is consistent with the observed x‐ray diagram of regenerated cellulose.

From a comparison of this minimum crystallinity with crystallinity determined by the infrared‐deuteration method, it is concluded that at least 14% of the total material cannot be truly described as either perfectly crystalline or perfectly amorphous. This fraction of material of intermediate order is registered as crystalline by x‐ray diffraction, but infrared spectroscopy suggests that it does not possess the precise molecular configuration characteristic of crystalline material. Support for this view of structure is reported from observations of differences in hydrogen‐bonding in amorphous regions of regenerated and bacterial celluloses. Infrared results show that OH groups which lie in the surface of crystallites are hydrogen‐bonded in a random amorphous manner and it is concluded that the material of intermediate order can be accounted for in terms of chains lying in the surface of crystallites of cross‐section 29 A. × 65 A.
Copolymerization of acrylonitrile and p‐sodium styrene sulfanate
Authors: Izumi Z. , Kiuchi H. , Watanabe M.
Published: April 2003

The copolymerization of acrylonitrile (AN) with sodium p‐styrenesulfonate (SSS) in aqueous solutions (of pH 3 and pH 7) has been investigated. Monomer reactivity ratios at 45°C. for AN and SSS are found to be r1 = 0.10 ± 0.02, r2 = 1.20 ± 0.10 at pH 3 and r1 = 0.05 ± 0.01, r2 = 1.40 ± 0.04 at pH 7, from which Price Q and e values for SSS of 0.76 and −0.26 at pH 3 and of 1.25 and −0.43 at pH 7 are calculated. Initial rates of copolymerization at 45°C. with ammonium persulfate (APS) as initiators were determined over the entire range of composition from pure AN to pure SSS, and it has been found that there is a sharp rise in copolymerization rates within 0.2–5 mole‐% monomer feed, sometimes being eight times larger than those in the neighboring range. The copolymerization in SSS monomer feed of 0.2–5 mole‐% occurs in the transition phase from homogeneous to heterogeneous, and the system is very viscous and slightly cloudy. From the investigation of the effect of initiator concentration on the copolymerization rate and the direct observation by an electron microscope, the sharp rise in copolymerization rates may reasonably be interpreted in terms of the emulsion copolymerization mechanism.
Thermodynamic properties of solutions of cellulose acetate and cellulose nitrate
Authors: Moore W. R. , Shuttleworth R.
Published: April 2003

Vapor pressure lowerings of solutions containing 10–50 wt.‐% of a secondary cellulose acetate and of a cellulose nitrate of similar degree of substitution in representative solvents have been measured over a range of temperature. Solvent activities and free energies, heats and entropies of dilution are obtained. At low polymer concentrations the cellulose acetate systems are endothermal but become exothermal at higher concentrations. Entropies of dilution show a somewhat similar variation with concentration when acetone, methyl acetate, and dioxane are used as solvents for the cellulose acetate, but with pyridine as solvent entropies are positive and increase with increasing polymer concentration. The systems cellulose nitrate‐acetone and cellulose nitrate‐methyl acetate are exothermal at all concentrations, but entropies of dilution are positive and increase with concentration from values not far from ideal to relatively large ones. An attempt is made to interpret these results in terms of solvation and chain stiffness. Values of the polymer‐solvent interaction parameter χ1 are obtained by use of polymer volume fractions calculated from the densities of the dry polymers. As the volume fraction of polymer increases in the cellulose acetate systems, χ1 would appear initially to fall from values characteristic of dilute solutions and then to increase. In the cellulose nitrate systems, χ1 falls from small positive to relatively large negative values. Values of the heat χh and entropy χs contributions to χ1 are also obtained. It is pointed out that it may be more logical to express polymer volume fraction in terms of solvated polymer and that this might lead to values of χ1, χh, and χs more in keeping with theories of polymersolvent interaction.
New features in polymer crystal growth from concentrated solutions
Authors: Bassett D. C. , Keller A. , Mitsuhashi S.
Published: April 2003

The three‐dimensional morphology of solution‐crystallized low pressure polyethylene has been examined for concentrations to 50% in xylene. Lamellar crystallization is characteristic of the whole range, and whenever diffraction examination has been possible, the lamellae have been shown to contain chain‐folded molecules. For crystallization from relatively dilute solutions (<0.3%) and below 75°C., earlier observations that the layers of multilayer crystals splay apart have been extended and the development of sheaving morphologies via the splaying of layers demonstrated. Sheaving has been interpreted as resulting from repulsion between portions of molecules excluded from the lamellar crystals. At higher concentrations and temperatures, molecules which crystallize through several lamellae become increasingly important. These are proposed as an explanation for a new, more compact, type of object which appears under the above conditions. They are designated axialites, as they consist of layers or layer packets splaying about a common axis (b). Viewed along this axis they appear sheaving, but as hexagons or fibrous ovals perpendicular to the axis. They thus resemble single crystals in some projections and incipient spherulites in others. Electron‐microscopic fine‐structure examination has shown that physical cohesion exists between the 100 A. terraces forming a layer packet on a 1000 A. scale. This is attributed to the interlamellar ties referred to above. This tying together of otherwise chain‐folded lamellae is considered as a plausible link between crystallization from dilute solution and from the melt. Disintegration and deformation of axialites has been studied in a preliminary way. Deformation has been found to consist of the relative displacement of otherwise intact layer packets. Some points concerning interlamellar connections and the possible relation between axialites and spherulites are also discussed.
Fundamental studies on cationic polymerization. III. Extension of mechanism studies to homogenous systems
Authors: Kirshenbaum I. , Kennedy J. P. , Thomas R. M.
Published: April 2003

Fundamental studies of the cationic polymerizations of isobutylene has been extended to the n‐pentane and carbon disulfide systems. The kinetic equation for the n‐pentane system is more complex than for other solvent systems because simplifying assumptions (which were possible for methyl chloride, ethyl chloride, and vinyl chloride) do not appear to be valid here. However, in all systems studied, the molecular weight of the polymer is determined principally by two competing chain breaking processes; namely, chain transfer from polymer to monomer and chain transfer or termination involving the solvent. The solvent reaction is important in polar solvents, especially at higher temperatures (e.g. −35°C.) but is much less important in either n‐pentane or carbon disulfide systems.
Study of the rate of heterogeneous polymerization of methyl acrylate in aqueous solution
Authors: Guha Tilak , Palit Santi R.
Published: April 2003

Study of the heterogeneous polymerization of methyl acrylate in dilute aqueous solution in a redox‐initiated system consisting in Na2S2O3K2S208 reveals the fact that the initial rate of polymerization increases with the increase in concentration of either of the redox pair. The rate, however, suffers a rapid deceleration in the course of polymerization in the region of high concentrations of the catalysts. At a low concentration of the initiators, addition of a small quantity of neutral electrolyte increases the rate, which falls off rapidly on further increase of the electrolyte concentration. Addition of emulsifiers in a concentration less than their critical micelle concentration inwater remarkably increases both the rate and the molecular weight. The rate of polymerization depends more or less linearly on monomer concentration when the concentration of the initiators is low in the medium. A monomer dependence tending to zero order is found when the catalyst concentration is high. Water‐soluble alcohols and glycols lower the rate when the insoluble phase in the heterogeneous polymerization is a stable colloid. Solvents such as dimethylformamide and benzene, which have strong affinity for the polymers produced in the medium, also reduce the rate. The peculiarities in the rate of this heterogeneous polymerization seem to be connected with the physical state of the insoluble polymer phase. The latter depends mainly on the ionic strength of the aqueous medium. At a low concentration of electrolytes, which may be either a neutral salt or water soluble electrolytic initiators such as K2S208/Na2S204, the insoluble phase is a stable colloid which changes via an unstable latex to a coarse precipitate on progressive increase of the electrolyte concentration in the medium. It appears that a kinetics similar to that of an emulsion polymerization operates when the insoluble phase is a stable colloid, suspension polymerization kinetics hold good when the insoluble phase is an unstable latex, and the kinetics of a typical “explosive” polymerization is the mechanism when the insoluble phase precipitates.
Grafting of poly (methyl methacrylate) to granular corn starch
Authors: Brockway C. E. , Moser K. B.
Published: April 2003

Graft copolymers were prepared by the radical‐initiated polymerization of methyl methacrylate in aqueous slurries of granular corn starch. High conversions of monomer were realized, giving products which were readily recovered by filtration. The products were free‐flowing, white powders, which by microscopic examination looked much like granular starch. Grafting was demonstrated by extracting the granular products with ethylene dichloride, which in most instances removed only a minor part of the poly(methyl methacrylate). When azoisobutyronitrile was used for initiation, a high conversion of monomer resulted, but about 90% of the polymer was extractable with ethylene dichloride. Further evidence for grafting was obtained by extraction of predissolved product, prepared by dissolving the granular product in dimethyl sulfoxide, to destroy the structure of the starch granules, and precipitating with alcohol. The fractions soluble in ethylene dichloride contained significant amounts of carbohydrate. Similar treatment of product prepared with azoisobutyronitrile initiation or of physical blends of starch and poly(methyl methacrylate) gave much more efficient separation of starch from PMMA. Failure to obtain grafting with AIBN initiation suggests that grafting occurs mainly as a result of attack on starch by radicals generated by the reaction of hydrogen peroxide or organic hydroperoxide with ferrous iron. Acid hydrolysis of the products removed the starch. The PMMA so recovered typically had viscosity‐average molecular weights of the order of 106, which suggests the grafts contained very long branch chains of PMMA attached at very infrequent intervals.
Molecular weight distribution in polypropylene glycol 2025
Authors: Morris R. J. , Persinger H. E.
Published: April 2003

The new applications of polypropylene glycols as chemical intermediates, particularly in the polyurethane field, have shifted emphasis from purely physical properties, such as density, viscosity, and volatility, to chemical properties, such as hydroxyl content, unsaturation, and molecular weight: Because much interest is also being shown in the uniformity of chain length, i.e., the “molecular purity” of the polypropylene glycol, methods were investigated for measuring this property. A liquid chromatographic procedure has been developed which will yield molecular weight distributions for polypropylene glycols in the 2025 number‐average molecular weight range. The results approximate, but do not match, the values obtained by theoretical calculations. Details of the method and a typical distribution curve are presented.
Homopolymerization of maleic anhydride. I. Preparation of the polymer
Authors: Lang John L. , Pavelich W. A. , Clarey H. D.
Published: April 2003

Maleic anhydride has been homopolymerized, contrary to accepted beliefs. Polymerization of either molten or dissolved monomer was initiated with the use of gammaradiation and free‐radical initiators. An anhydride having [η] = 0.146 dl./g. in acetophenone had a molecular weight of 23,100 (free acid), DP = 199, by the light‐scattering method. The carboxyl group propinquity is responsible for peculiar behavior of aqueous solutions of salts of the poly‐acid.
Polyethylene terephthalate structural studies
Authors: Schmidt P. G.
Published: April 2003

The absorption intensity of a given infrared absorption band, in the infrared spectrum of an oriented polymer is composed of an orientation and a structural factor. A method is discussed, using polarized infrared radiation, which will measure the contribution of each. The ethylene glycol linkage of the polyethylene terephthalate molecule may exist in either of two forms. These forms are rotational isomers. The trans form of the molecule is the extended form, the gauche form is the relaxed form. The amorphous regions of polyethylene terephthalate films have been found to contain both of these isomers. Polymer orientation is summarized in terms of transition moment types. Orientation parameters characteristic of polyethylene terephthalate films are defined.
Molecular orbital theory of reactivity in radical polymerization. Part III
Authors: Hayashi K. , Yonezawa T. , Okamura S. , Fukui K.
Published: April 2003

The chemical reactivity in diene type polymerization and degradative chain transfer is discussed by the theory previously proposed by the present authors. In addition to this, a molecular orbital procedure to calculate Q and e values is presented. Further, the stabilization energy and the reactivity ratios in various copolymerizations are calculated. The results coincide with experiment satisfactorily.