bluuebunny/crossref_metadata_2025 huggingface dataset:
A new blind source separation method based on fractional lower‐order statistics
Authors: Zha Daifeng , Qiu Tianshuang
Published: March 2006

We proposed neural network structures related to multilayer feed‐forward networks for performing blind source separation (BSS) based on fractional lower‐order statistics. As alpha stable distribution process has no its second‐ or higher‐order statistics, we modified conventional BSS algorithms so that their capabilities are greatly improved under both Gaussian and lower‐order alpha stable distribution noise environments. We analysed the performances of the new algorithm, including the stability and convergence performance. The analysis is based on the assumption that the additive noise can be modelled as alpha stable process. The simulation experiments and analysis show that the proposed class of networks and algorithms is more robust than second‐order‐statistics‐based algorithm. Copyright © 2006 John Wiley & Sons, Ltd.
Surfactant Systems: A Survey of the Transcontinental Gas Pipeline from Houston to New Jersey
Authors: Morozov Petia
Published: March 2006

The Transcontinental Pipeline, Transco, is a 10,560‐mile line that traverses the US, transporting natural gas from its source in the Gulf of Mexico to the East Coast. Petia Morozov describes the postwar engineering feat that made the pipeline a reality, and also reveals the web of myriad agreements, with often diametrically opposed parties or interests, that support its rights of way and management. Copyright © 2005 John Wiley & Sons, Ltd.
Squatting Geometries ‐ Guerilla Barcelona: Technological Appropriations of the Over‐Planned City
Authors: Luis José , Manau Echeverria , Mansilla Jordi , Jorge Ortoneda , Solano Perea
Published: March 2006

In the 1980s, Barcelona became the darling of urban regeneration. Its mayor and city authorities gained awards and recognition the world over. However, 111 architects José Luis Echeverría Manau, Jordi Mansilla Ortoneda and Jorge Perea Solano depict a very different, more sinister view of the city's development, in which the metropolis has been reshaped to serve private rather than civic interests. They explain how subversive citizens' groups are hitting back and realising their collective power through the strategic, yet often spontaneous use of portable communication and remote‐sensing technologies. Copyright © 2005 John Wiley & Sons, Ltd.
Serpentine Gallery Pavilion 2005
Authors: Melvin Jeremy
Published: March 2006

The Serpentine Gallery Pavilion is a unique programme that commissions architecture for art's sake. It provides innovative architects, who have not previously built in the UK, with the opportunity to design a cutting‐edge structure for a summer show. Jeremy Melvin describes how Portuguese masters Alvaro Siza and Eduardo Souto de Moura, in collaboration with Cecil Balmond of Arup, have produced ‘an urban design’ that is perfectly calibrated to respond to its Hyde Park setting. Copyright © 2005 John Wiley & Sons, Ltd.
Three‐Dimensionally Ordered Gold Nanocrystal/Silica Superlattice Thin Films Synthesized via Sol–Gel Self‐Assembly
Authors: Fan H. , Wright A. , Gabaldon J. , Rodriguez A. , Brinker C. J. , Jiang Y.‐B.
Published: March 2006

Nanocrystals and their ordered arrays hold many important applications in fields such as catalysis, surface‐enhanced Raman spectroscopy based sensors, memory storage, and electronic and optical nanodevices. Herein, a simple and general method to synthesize ordered, three‐dimensional, transparent gold nanocrystal/silica superlattice thin films by self‐assembly of gold nanocrystal micelles with silica or organosilsesquioxane by spin‐coating is reported. The self‐assembly process is conducted under acidic sol–gel conditions (ca. pH 2), ensuring spin‐solution homogeneity and stability and facilitating the formation of ordered and transparent gold nanocrystal/silica films. The monodisperse nanocrystals are organized within inorganic host matrices as a face‐centered cubic mesostructure, and characterized by transmission electron spectroscopy and X‐ray diffraction.
High prevalence and correlates of low bone mineral density in young adults with sickle cell disease
Authors: Miller Redonda G. , Segal Jodi B. , Ashar Bimal H. , Leung Sophia , Ahmed Shamim , Siddique Shabina , Rice Tasha , Lanzkron Sophie
Published: March 2006

Sickle cell disease (SCD) is a prevalent genetic disorder in which sickle hemoglobin leads to tissue hypoxia and adverse effects on bone. Published studies suggest that children with SCD often have undiagnosed osteopenia or osteoporosis. Minimal data exist on the prevalence of low bone mineral density (BMD) in adults. Our objective was to describe the prevalence of osteopenia and osteoporosis in adults with SCD and to identify patient or disease characteristics associated with low BMD. We conducted a cross‐sectional study of adults with SCD. Through questionnaires, we collected data about disease course and osteoporosis risk factors. Patients underwent dual X‐ray absorptiometry (DXA) measurement of BMD at the hip, spine, and forearm and sampling of blood and urine for markers of bone turnover, sickle cell disease severity, and secondary causes of osteoporosis. Our main outcome measure was prevalence of osteopenia and osteoporosis as defined by WHO criteria. Of 32 adults with SCD (14 men and 18 women) with a mean age of 34 years, 72% (95% confidence interval 53–86%) had low BMD at one or more anatomic sites. Thirteen patients were classified as osteoporotic and 10 as osteopenic. The prevalence of low BMD was greatest in the lumbar spine (66% of patients). Significant correlates of decreased BMD included low BMI (P < 0.01), male sex (P = 0.02), and low serum zinc concentrations (P < 0.01). The prevalence of osteopenia and osteoporosis in young adults with SCD is extremely high. Further research is needed to address fracture risk and therapeutic interventions. Am. J. Hematol. 81:236–241, 2006. © 2006 Wiley‐Liss, Inc.
False‐negative factor V Leiden genetic testing in a patient with recurrent deep venous thrombosis
Authors: Libby Edward N. , Booker Jessica K. , Gulley Margaret L. , Garcia David , Moll Stephan
Published: March 2006

False‐negative genetic testing of the factor V Leiden (fVL) mutation is unusual. We report a case of a young woman with a history of deep venous thrombosis tested for the fVL at four separate laboratories on four separate dates. Two laboratories reported the patient to be heterozygous for the fVL, while the other two reported no evidence of a mutation. Testing methods of the various laboratories were reviewed, and additional testing was performed on stored and newly drawn DNA samples, including sequencing of the fVL gene segment. The preponderance of evidence indicates the patient to be heterozygous for the fVL mutation. Dissection of data suggests that either sample misidentification or faulty allele specific amplification methods could have led to false‐negative results in two laboratories. In one of the two laboratories, misinterpretation of results and clerical error could not be excluded. There is a need for standardization of optimized fVL genetic testing methods. Further education of ordering physicians on the limitations of genetic testing is necessary. Am. J. Hematol. 81:284–289, 2006. © 2006 Wiley‐Liss, Inc.
Successful reduced intensity allogeneic stem cell transplantation for systemic AL amyloidosis
Authors: Imamura Tomoyuki , Ogata Masao , Kohno Kazuhiro , Tomo Tadashi , Ohtsuka Eiichi , Kikuchi Hiroshi , Kadota Jun‐ichi
Published: March 2006

No established treatments for systemic AL amyloidosis have been determined, and only four reports have described allogeneic stem cell transplantation for this disease. We report the case of a patient with orthostatic hypotension, diarrhea, nephrotic syndrome, and cardiac amyloidosis due to systemic AL amyloidosis. Reduced intensity allogeneic stem cell transplantation (RIST) was performed using a conditioning regimen comprising fludarabine 125 mg/m2 and melphalan 90 mg/m2. Hematologically complete remission and symptomatic improvement were obtained without severe transplantation‐related complications. RIST may thus offer a useful treatment strategy for systemic AL amyloidosis complicated by cardiac amyloidosis. Am. J. Hematol. 81:281–283, 2006. © 2006 Wiley‐Liss, Inc.
Hemoglobin Loves Park [β68 (E12) Leu→Phe]: Report of five cases including one originating from a de novo mutation
Authors: Ferreira Cristina , Hoyer James D. , Miranda Armandina , Picanço Isabel , Almendra Vanda , Seixas Maria Teresa , Almeida Teresa , Romão Luísa , Faustino Paula
Published: March 2006

Hemoglobin (Hb) Loves Park [β68 (E12) Leu→Phe] was identified in a 2‐year‐old Portuguese boy with anemia, microcytosis, and hypochromia. This Hb variant was detected by isoelectric focusing and quantified by reverse‐phase high‐performance liquid chromatography (HPLC) (48.4%), and the DNA mutation was identified by HBB (β‐globin gene) sequencing. Hematological and biochemical analyses performed on his parents revealed normal hematological parameters and normal hemoglobin and globin chain profiles. DNA sequence analysis of the HBB gene of both parents showed the absence of the Hb Loves Park mutation. Study of the haplotypes in the β‐globin gene cluster confirmed parenthood. Moreover, paternity was confirmed by the study of nine short tandem repeats (STRs) and four variable‐number tandem repeat (VNTRs) loci. The most likely explanation for these results is that the Hb Loves Park mutation has occurred de novo in this family. The original American cases of Hb Loves Park, from a family of Italian origin, which were never published, as well as two additional cases, are also included in this report. Functional studies revealed that Hb Loves Park is stable and has a decreased oxygen affinity. Am. J. Hematol. 81:256–261, 2006. © 2006 Wiley‐Liss, Inc.
Benign chronic neutropenia with abnormalities involving 16q22, affecting mother and daughter
Authors: Glasser Lewis , Meloni‐Ehrig Aurelia , Joseph Plakyil , Mendiola Jennifer
Published: March 2006

We report a case of familial, chronic, benign neutropenia in a 17‐year‐old female showing (1) the spontaneous expression of a heritable rare fragile site at 16q22 and (2) a deletion at the same region. The del(16)(q22), which most likely originated from the fragile site, was the main clonal abnormality detected in the patient's bone marrow cells, whereas a few cells with either del(16)(q22) or fra(16)(q22) were seen in the patient's peripheral blood. Interestingly, the del(16q) was also detected in the patient's uncultured cells, as demonstrated by FISH, excluding an in vitro origin of the del(16q) during culture. The bone marrow was hypocellular with decreased neutrophils and their precursors. Absolute neutrophil counts ranged from (0.62 to 1.24) × 109/L with a median value of 1.02 × 109/L. The patient had a more severe neutropenia than her mother, which correlated with the presence of more cells with del(16q) in the marrow. The patient's mother, who was also diagnosed with neutropenia, revealed only a few cells with the rare fra(16)(q22) in her peripheral blood cells, whereas her bone marrow showed cells with both fra(16)(q22) and del(16)(q22), although the del(16q) was present in only 2/20 cells. Some possible candidate genes contributing to the pathogenesis of the neutropenia are discussed. Chromosome abnormalities involving the 16q22 breakpoint have been observed in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). In this patient, the del(16)(q22) risk factor is unknown for subsequent development of MDS or AML. Another point to consider is the need to determine the origin of a chromosome abnormality, particularly when the clinical picture does not fit the chromosome findings. Although, the observation of a constitutional structural abnormality in a mosaic form is an extremely rare event, it is somewhat different in the case of a fragile site expression, which can, as in this case, be present in some cells and not in others. Am. J. Hematol. 81:262–270, 2006. © 2006 Wiley‐Liss, Inc.
Dural venous sinus thrombosis in a patient with sickle cell disease: Case report and literature review1
Authors: Ciurea S.O. , Thulborn K.R. , Gowhari M.
Published: March 2006

We report a case of dural venous sinus thrombosis (DVST) in a patient who developed seizures following exchange transfusion for treatment of acute chest syndrome associated with sickle cell disease. Evaluation with magnetic resonance imaging and magnetic resonance venography of the brain indicated left sigmoid sinus thrombosis. The history and laboratory evaluation did not reveal any other inherited or acquired hypercoagulable states. This is the fourth case of dural venous sinus thrombosis associated with sickle cell disease reported in literature. The patient had a favorable outcome with early treatment of unfractionated heparin. Am. J. Hematol. 81:290–293, 2006. © 2006 Wiley‐Liss, Inc.
Suppression of ionization and optimization of assay for 3‐hydroxy fatty acids in house dust using ion‐trap mass spectrometry
Authors: Alwis K. Udeni , Larsson Lennart , Milton Donald K.
Published: March 2006

Background

3‐Hydroxy fatty acids (3‐OHFAs), components of lipid A of gram‐negative bacteria are useful chemical markers of endotoxin.

Methods

We analyzed 3‐OHFAs in house dust as trimethylsilyl (TMS) methyl ester derivatives in the electron impact ionization mode using gas chromatography ion‐trap mass spectrometry. Linear calibrations with r > 0.995 were observed for all the 3‐OHFA methyl ester external standards.

Results

Recovery efficiency experiments with house dust demonstrated that accurate quantification requires calibration curves to be subjected to phase separation and solid phase extraction (SPE) because of differing clean‐up losses according to chain length of 3‐OHFAs. Recovery experiments also demonstrated interference with detection of C16:0 by the ion trap, which may be due to suppression of ionization by a constituent in house dust. Interference was overcome by injecting 1:4 dilutions of derivatized samples. The range of recoveries was 89.3%–111.5% for 3‐OHFAs added to house dust. The reproducibility of injections was high (CV for C14:0 = 2.36%). The limit of detection (LOD) was 0.15 ng/mg for each 3‐OHFA.

Conclusions

The modifications we made included: use of 3‐hydroxy C11:0 and C13:0 methyl esters as internal standards, subjecting calibration standards to phase separation and SPE; addition of water to phase separation; addition of 1‐pentadecanol as a carrier; injecting 1:4 diluted TMS derivatives of 3‐OHFAs; and monitoring both m/z 131 and 133 ions to improve stability of area measurements for product ions. This method of optimization establishes an appropriate technique for quantification of 3‐OHFAs in house dust. Am. J. Ind. Med. 49:286–295, 2006. © 2006 Wiley‐Liss, Inc.
Recombinant factor C assay for measuring endotoxin in house dust: Comparison with LAL, and (1 → 3)‐β‐D‐glucans
Authors: Alwis K. Udeni , Milton Donald K.
Published: March 2006

Background

Measurement of exposure to environmental endotoxin is frequently performed using a Limulus amebocyte lysate (LAL) based assay. Recently, a new method has become available with similar sensitivity and potentially greater specificity using recombinant Factor C (rFC) from the horseshoe crab Carcinoscorpius rotundicauda. A preliminary study was carried out to determine the comparability of LAL and rFC in measuring endotoxins in house dust for large scale epidemiologic studies.

Methods

House dust samples were collected from family rooms by vacuuming 1 m2 of the center of the room. Sixty sieved house dust samples were assayed for endotoxin by LAL (Cambrex, KQCL lysate) and rFC (Pyrogene, Cambrex) and for (1 → 3)‐β‐D‐glucans by ELISA. The resistant parallel line estimation was used for data analysis of LAL and rFC. A four‐parameter logistic fit with inverse prediction was used to calculate (1 → 3)‐β‐D‐glucan levels of the samples.

Results

The spike recovery was 113.63% (95% CI = 101.69, 125.57%) for LAL and 99.69% (95% CI = 90.14, 109.24%) for rFC assays. The LAL assay gave higher endotoxin estimates compared with rFC. The LAL and rFC estimates were highly correlated (r = 0.86, P < 0.0001). The difference between LAL and rFC endotoxin estimates correlated with the LAL estimates (r = 0.51, P < 0.0001). However, the difference was not correlated with (1 → 3)‐β‐D‐glucans.

Conclusion

LAL and rFC gave comparable results, hence either assay can be used for studies of endotoxin exposure. The current study shows that (1 → 3)‐β‐D‐glucan is not a major factor interfering with endotoxin measurements in house dust using a Cambrex KQCL LAL preparation. Am. J. Ind. Med. 49:296–300, 2006. © 2006 Wiley‐Liss, Inc.
Adiposity affects human response to inhaled organic dust
Authors: Cormier Yvon , Israël‐Assayag Evelyne
Published: March 2006

Background

Swine containment facilities are often highly contaminated with organic dusts that often contain varying levels of endotoxins and other microbial products. This study was performed to evaluate the effect of obesity on the inflammatory response induced by chronic or acute exposure to swine confinement buildings (SCB).

Methods

Two separate studies were performed; Study I included 36 SCB long‐time workers and a control group of 35 matched male hospital workers never exposed to SCB. In Study II, 14 naïve healthy young subjects (8 overweight and 6 lean) volunteered to be acutely exposed to a SCB environment for 5 hr. Markers of sub‐clinical inflammation linked to obesity (C‐reactive protein (CRP), interleukin 6 (IL‐6)) or to active inflammation (soluble adhesion molecules, IL‐8, TNF) were measured.

Results

In the first study, positive correlations were found between girth circumference and serum levels of IL‐6 (r = 0.57, P = 0.0003) and CRP (r = 0.62, P < 0.0001) in the control group. These correlations were however blunted or lost in the SCB workers group who showed positive correlations between girth circumference and soluble l‐selectin (r = 0.34, P = 0.04), TNFα (r = 0.37, P = 0.03), ICAM‐1 (r = 0.61, P < 0.0001).

In the second study involving acute SCB exposure of naïve volunteers, no significant differences were observed between normal weight and overweight subjects for white blood cells, nasal lavage cell counts, and IL‐8 levels. However, higher levels of CRP, TNF, and IL‐6 were detected in overweight volunteers compared to those who were lean.

Conclusions

In pig farmers (Study I), environmentally induced chronic inflammation appears to blunt the sub‐clinical inflammation linked to obesity, whereas in naïve volunteers of Study II, environmentally induced acute inflammation seems to have a potentiating effect on obesity‐related inflammatory markers. Am. J. Ind. Med. 49:281–285, 2006. © 2006 Wiley‐Liss, Inc.
Pesticide safety behaviors in Latino farmworker family households
Authors: Rao Pamela , Gentry Amanda L. , Quandt Sara A. , Davis Stephen W. , Snively Beverly M. , Arcury Thomas A.
Published: March 2006

Background

Studies to assess pesticide exposure of individuals living in agricultural settings suggest that farmworkers create a “take‐home” pathway from the fields to the home that increases exposure risk for non‐farmworker household members.

Methods

A survey was conducted with 142 Latino women in farmworker family households in North Carolina to identify predictors of adherence to pesticide safety behaviors that may affect take‐home exposure risk. Behaviors included changing work clothes before entering the house, storing and washing contaminated work clothes separately from family clothing, and showering upon returning home.

Results

The number of farmworkers in the household was negatively associated with adherence to recommended changing, storing, and showering behaviors. Most workers followed recommended laundry procedures for work clothes.

Conclusions

Results support existing evidence for a take‐home pathway for pesticide residues in homes with several farmworkers. Pesticide safety education needs to reinforce behaviors that reduce take‐home exposure in farmworker households. Am. J. Ind. Med. 49:271–280, 2006. © 2006 Wiley‐Liss, Inc.
Ten‐year comparison of BMI, body fat, and fitness in the workplace
Authors: Harbin Gary , Shenoy Catherine , Olson John
Published: March 2006

Background

Overweight, obestity, and lack of fitness in America is reported to be increasing at an accelerated pace. This national trend has serious health and economic ramifications not only for the general population but also directly for industry. Obesity in the workplace has resulted in increased expenses to industry: directly through increased medical costs and indirectly through decreased productivity. The intent of this study is to define changes in fitness and body fat percentage in a working population in an isogeographical area over the past decade.

Methods

Data accumulated during a routine post‐offer testing program were divided into two groups composed of new industry hires tested from 1990 to 1992 and from 2000 to 2002. Body fat was measured with a standard skinfold. The body fat percentage and body mass index (BMI) from year 1990 were compared to those from year 2000. Fitness was assessed through an individual's ability to perform a timed maximum number of sit‐ups and squats.

Results

There was no significant difference in the BMI between the year 1990 group and the year 2000 group (P = 0.132 for females and P = 0.110 for males). There was a significant increase in body fat percentage from the 1990 group to the 2000 group (P = 0.000 for females and P = 0.000 for males). A significant decrease in fitness was observed for both males and females during the 10‐year interval of the study.

Conclusions

Percent body fat appears to be a better indicator than BMI for utilization in industry for evaluation of obesity in the workplace. The differences in significance levels between BMI and percent body fat suggest that a decrease in leisure‐time fitness activities could potentially contribute to the trend toward obesity. This study demonstrates that strength and/or fitness are important indicators that industry should monitor in order to improve the health and fitness of the workforce. Direct measurement of percent body fat and fitness indices are a more precise means than BMI for monitoring the workforce especially if employers are going to reward healthy behavior. Am. J. Ind. Med. 49:223–230, 2006. © 2006 Wiley‐Liss, Inc.
Fatal motor vehicle crashes among veterans of the 1991 Gulf War and exposure to munitions demolitions at Khamisiyah: A nested case‐control study
Authors: Gackstetter Gary D. , Hooper Tomoko I. , DeBakey Samar F. , Johnson Amy , Nagaraj Barbara E. , Heller Jack M. , Kang Han K.
Published: March 2006

Background

A proposed explanation for the observed higher risk of fatal motor vehicle crashes (MVC) among 1991 Gulf War‐deployed veterans is neurocognitive deficits resulting from nerve agent exposure at Khamisiyah, Iraq. Our objective was to assess any association between postwar fatal MVC and possible nerve agent exposure based on 2000 modeled plume data.

Methods

Cases were defined as MVC deaths with a record in the Department of Transportation Fatality Analysis Reporting System through 1995. Cases (n = 282) and controls (n = 3,131) were derived from a larger nested case‐control study of Gulf War‐era veterans and limited to Army, male, deployed personnel. Exposure and cumulative dose by case‐control status were analyzed using multivariate techniques.

Results

Exposure status was not associated with fatal MVC (OR 0.96, 95% CI 0.72–1.26), nor were tertiles of cumulative dose.

Conclusions

Findings do not support an association between possible exposures at Khamisiyah and postwar fatal MVC among Gulf War veterans. Am. J. Ind. Med. 49:261–270, 2006. Published 2006 Wiley‐Liss, Inc.
Nutritional chemistry of foods eaten by gorillas in Bwindi Impenetrable National Park, Uganda
Authors: Rothman Jessica M. , Dierenfeld Ellen S. , Molina Denis O. , Shaw Andrea V. , Hintz Harold F. , Pell Alice N.
Published: March 2006

Foods eaten by gorillas (Gorilla beringei) in Bwindi Impenetrable National Park (BINP), Uganda, were analyzed for their nutrient content. The goal of the study was to assess the amounts of fiber, protein, and sugars in the foods eaten by the Bwindi gorillas, and to determine whether condensed tannins and cyanide are present in these foods. A total of 127 food plant parts representing 84 plant species eaten by two groups of Bwindi gorillas were collected, processed, and analyzed for their chemical contents. The Bwindi gorilla ate foods that contain 2–28% crude protein (CP), 21–88% neutral detergent fiber (NDF), 14–60% acid detergent fiber (ADF), 2–42% acid detergent lignin (ADL), and ≤1–50% water‐soluble carbohydrates (WSC) on a dry matter (DM) basis. Moisture in these foods ranged from 7% to 96%. Approximately 35% of the foods analyzed contained condensed tannins, and two foods contained cyanogenic glycosides. This is the first detailed report regarding the nutritional chemistry of gorilla foods in Bwindi, many of which are also eaten by other primates. This unique data set adds to our knowledge about the nutritional composition of foods eaten by gorillas across habitats, is useful for understanding aspects of feeding behavior, and provides valuable comparative data for optimizing the diets of gorillas ex situ. Am. J. Primatol. 68:1–17, 2006. © 2005 Wiley‐Liss, Inc.
Ringschlussmetathese: ein Schlüssel zur Arensynthese
Authors: Donohoe Timothy J. , Orr Allan J. , Bingham Matilda
Published: March 2006

Die Anwendung der Metathese, besonders der Ringschlussmetathese (RCM) zur Bildung von Fünf‐ und Sechsringen, ist heute in der organischen Chemie weit verbreitet; dennoch gibt es überraschend wenige Beispiele für ihre Anwendung zur Synthese aromatischer Verbindungen. Deren Bedeutung in der medizinischen Chemie und der Naturstoffsynthese, verbunden mit der Wirksamkeit von RCM‐Katalysatoren und ihrer Toleranz gegenüber funktionellen Gruppen, gibt Anlass, die Anwendung der RCM in der Arensynthese zu untersuchen. Die Synthese von heterocyclischen und carbocyclischen Arenen unter Verwendung der RCM wird in einigen Publikationen als Schlüsselschritt beschrieben. Galt das gebildete Aren in vielen frühen Beispielen noch als unerwünschtes Abbauprodukt, so wurden in letzter Zeit gezielt Methoden zur Arensynthese über RCM entwickelt.
Carrier‐bound methotrexate. II. Water‐soluble polyaspartamide methotrexate conjugates with amide links in polymer–drug spacer
Authors: Caldwell Gregg , Meirim Maria G. , N'Da David D. , Neuse Eberhard W.
Published: March 2006

In Part I of this series, conjugation of methotrexate (MTX) to water‐soluble polyaspartamide carriers was accomplished through ester link formation between an MTX carboxyl group and a carrier‐attached hydroxyl function. Contrasting with that type of anchoring link, this project utilizes amide formation as the means of drug conjugation. This is achieved through condensation of one of the drug's carboxyl groups with a carrier‐attached primary amine function. Derived from polysuccinimide by a time‐proven nucleophilic ring‐opening process in the presence of aliphatic diamines, polyaspartamide‐type carriers 1–12 comprise subunits equipped with tert‐amine or hydroxyl side group terminals for hydrosolubilization and other subunits equipped with primary amine terminals as drug‐binding sites. MTX conjugation with these carriers is effected in aprotic solvent, the reaction being mediated by 2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium hexafluorophosphate. The water‐soluble conjugates are fractionated and purified by size exclusion chromatography and dialysis; they are isolated by freeze‐drying in typical yields of 40–65%. In the molar MTX/NH2 feed ratios that are chosen (generally 1.2–1.3) and with the mole fractions of drug‐binding subunits restricted to 10 and 20%, drug loading in the resultant conjugates approximates 20–30% by mass. In follow‐on study, conjugates 1‐MTX–12‐MTX thus obtained will be screened in cell culture tests for antiproliferative activity against a number of human cancer lines. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3415–3424, 2006
Core/shell SiOx@PAM nanospheres from UV‐assisted surface‐initiated free radical polymerization
Authors: Liu Peng , Zhang Liuxue , Su Zhixing
Published: March 2006

The core/shell SiOx@polyacrylamide (SiOx@PAM) nanospheres were successfully prepared by the in situ surface‐initiated free radical polymerization of acrylamide (AM) from the silica nanoparticles with self‐assembled monolayers (SAMs) of N‐methyl aniline (NMA) in presence of benzophonone via a precipitation polymerization method under the ultraviolet (UV) irradiation. The conversion of monomer (C%) and the percentage of encapsulating (PE%), calculated from the elemental analyses (EA) results, reached 20.9 and 51.0% after 150 min of UV‐irradiation, respectively. It is consistent with the analyses of TGA. Fourier transform infrared (FTIR) analyses also confirmed the formation of the core/shell SiOx@PAM nanospheres. And it was investigated that the silica nanoparticles had been encapsulated with PAM from the X‐ray photoelectron spectrometer (XPS) analyses. The analysis results of transmission electron microscope (TEM) showed that the diameters of the SiOx@PAM nanospheres were in the range of 50–200 nm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3433–3438, 2006
Some monomer reactivity ratios of styrene and (meth)acrylates in the presence of TEMPO
Authors: Jianying Huang , Jiayan Chu , Jiaming Zhuang , Yihong Chen , Lizong Dai , Yousi Zou
Published: March 2006

The living free‐radical copolymerizations of styrene (St) with the polar monomers (methyl methacrylate (MMA), ethyl methacrylate (EMA), butyl methacrylate (BMA), methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), 2‐hydroxyethyl acrylate (HEA), and vinyl acetate (VAc)) mediated by TEMPO and BPO as initiator at 125°C had been analyzed by 1H NMR and gel permeation chromatography (GPC). The data from GPC showed that the polydispersities of the resulted copolymers were below 1.5, and the rate of polymerization increased, while the polydispersity declined with increase in St molar fraction in the feed. Monomer reactivity ratios had been determined by expanded Kelen–Tüdos method. rSt = 1.32, rMA = 0.14; rSt = 1.17, rEA = 0.23; rSt = 0.83, rBA = 0.20; rSt = 0.74, rMMA = 0.25; rSt = 0.76, rEMA = 0.30; rSt = 1.27, rBMA = 0.59; rSt = 1.67, rVAc = 1.05; and rSt = 0.28, rHEA = 0.43. In the copolymerization of St with acrylates the monomer reactivity ratio r1 (St) decreases and in the copolymerization of St with methacrylates the monomer reactivity ratio r1 (St) increases while the length of the substituted group increases. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3531–3535, 2006
Epoxy‐tert‐butyl poly(cyanoarylene ether) blends: Phase morphology, fracture toughness, and mechanical properties
Authors: Saxena Akanksha , Francis Bejoy , Rao V. Lakshmana , Ninan K. N.
Published: March 2006

Tert‐butyl hydroquinone–based poly(cyanoarylene ether) (PENT) was synthesized by the nucleophilic aromatic substitution reaction of 2,6‐dichlorobenzonitrile with tert‐butyl hydroquinone using N‐methyl‐2‐pyrrolidone (NMP) as solvent in the presence of anhydrous potassium carbonate in a nitrogen atmosphere at 200°C. PENT‐toughened diglycidyl ether of bisphenol A epoxy resin (DGEBA) was developed using 4,4′‐diaminodiphenyl sulfone (DDS) as the curing agent. Scanning electron micrographs revealed that all blends had a two‐phase morphology. The morphology changed from dispersed PENT to a cocontinuous structure with an increase in PENT content in the blends from 5 to 15 phr. The viscoelastic properties of the blends were investigated using dynamic mechanical thermal analysis. The storage modulus of the blends was less than that of the unmodified resin, whereas the loss modulus of the blends was higher than that of the neat epoxy. The tensile strength of the blends improved slightly, whereas flexural strength remained the same as that of the unmodified resin. Fracture toughness was found to increase with an increase in PENT content in the blends. Toughening mechanisms like local plastic deformation of the matrix, crack path deflection, crack pinning, ductile tearing of thermoplastic, and particle bridging were evident from the scanning electron micrographs of failed specimens from the fracture toughness measurements. The thermal stability of the blends were comparable to that of the neat resin. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3536–3544, 2006
Mechanical properties, stress‐relaxation, and orientation of double bubble biaxially oriented polyethylene films
Authors: Bobovitch A. L. , Tkach R. , Ajji A. , Elkoun S. , Nir Y. , Unigovski Y. , Gutman E. M.
Published: March 2006

Biaxially oriented linear low density polyethylene (LLDPE) films were produced using the double bubble process with different machine direction (MD) orientation levels and the same transverse direction (TD) blow‐up ratio. Their mechanical behavior was characterized in terms of the tensile strength and tear resistance. The viscoelastic behavior of oriented films was studied using dynamic‐mechanical thermal analysis (DMTA). The microstructure and orientation were characterized using microscopy, X‐ray diffraction pole figures, and birefringence. The results indicate that MD ultimate tensile strength increases and the TD one decreases with MD stretching ratio. Tear propagation resistance, in general, remained mainly constant in TD and decreased in MD, as the draw ratio was increased. The morphology analyses exhibit a typical biaxial lamellar structure for all samples with different lamellar dimensions. Orientation of c‐axis in crystalline phase, molecular chain in amorphous phase along MD increased with draw ratio. In most crystals, a‐axis was located in the normal direction (ND) and the b‐axis in the ND–TD plane. A good correlation was observed between c‐axis orientation factor and MD mechanical properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3545–3553, 2006
Oxidative copolymerization between toluidine and vinyl acetate
Authors: Li Xin‐Gui , Dong Zhi‐Qing , Huang Mei‐Rong , Shao Hui‐Li , Hu Xue‐Chao
Published: March 2006

A series of copolymers between o‐toluidine (OT) and vinyl acetate (VA) was synthesized by a chemically oxidative polymerization, which was carried out by three different methods: suspension solution precipitation, emulsion and inverse emulsion copolymerizations by using iron trichloride, and ammonium persulfate as oxidant. The progress in the copolymerization, polymerization yield, structure, and properties of the resulted OT/VA copolymers were systematically characterized by solution potential/temperature monitor, laser particle size, FTIR, UV–vis, and thermogravimetry techniques. The results show that the diameter, spectral characteristics, solubility, film formability, electrical conductivity, and thermostability of the virgin polymer particles formed exhibit a nonmonotonic dependence on the OT/VA ratio, suggesting an occurrence of an oxidative copolymerization between OT and VA monomers. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3562–3573, 2006
Possibilities of collagen adsorption on some polymeric matrices based on styrene copolymers
Authors: Elena Nita Loredana , Chiriac Aurica P. , Vasile Cornelia
Published: March 2006

Seven matrices based on polystyrene and styrene copolymers, with acrylic and methacrylic acid, acryl‐ and methacrylamide, and acrylonitrile and maleic anhydride, are tested in respect of their capacity of collagen adsorption. The aim of the study is to correlate the collagen coupling capacity by the nature of the monomers and the ability of functional groups to obtain biomaterials. The prepared vinylic polymers are relatively hydrophobic. These hydrophobic properties, together with the large mesh interstices, hinder smooth‐cell seeding. In contrast, collagen offers the advantage of specific cell interactions and hydrophilicity. Therefore, synthetic polymers and collagen have been hybridized to combine their advantages. The biocompatibilization process consists of physical immobilization of the protein onto the synthesized matrice surfaces. The content of the adsorbed protein was correlated with the conditions of capture, solution pH, and sorption temperature, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3554–3561, 2006
Thermal stability of polypropylene/carbon nanofiber composite
Authors: Chatterjee Arobindo , Deopura B. L.
Published: March 2006

Thermal stability of polypropylene and carbon nanofibre composite system has been studied using Thermogravimetric Analysis, Limited Oxygen Index (LOI), Flammability, Calorimetry, and Oxidation Induction Time techniques. Definite improvement in thermo‐oxidative stability of the composite system has been observed. Improvement in LOI and a distinct change in the burning characteristics suggest a reduction in potential fire hazards. The nanocomposite system will have enhanced anti‐ageing characteristics and require more stringent conditions for the initiation of burning and the ultimate impact of burning will be less. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3574–3578, 2006
Fluorinated‐plasma modification of polyetherimide films
Authors: Kaba Meriyam , Essamri Azzouz , Mas Andre , Schue Francois , George G. A. , Cardona F. , Rintoul L. , Wood B. J.
Published: March 2006

Ultem 1000 polyetherimide films prepared by cast‐evaporating technique were covered with a 1H,1H,2H‐tridecafluoro‐oct‐1‐ene (PFO) plasma‐polymerized layer. The effects of the plasma exposure time on the surface composition were studied by X‐ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and surface energy analysis. The surface topography of the plasma layer was deduced from scanning electron microscopy. The F/C ratio for plasma‐polymerized PFO under the input RF power of 50 W can be as high as 1.30 for 480 s and ∼0.4–2 at % of oxygen was detected, resulting from the reaction of long‐lived radicals in the plasma polymer with atmospheric oxygen. The plasma deposition of fluorocarbon coating from plasma PFO reduces the surface energy from 46 to 18.3 mJ m−2. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3579–3588, 2006
Synthesis and characterization of radiation grafted copolymer for removal of nonionic organic contaminants
Authors: Sokker H. H. , Ghaffar A. M. Abdel , Nada A. M. A.
Published: March 2006

Nonionic organic contaminants such as phenol, benzene, and toluene from contaminated wastewater on laboratory scale can be effectively sorbed by cellulosic wood pulp sheet incorporated with three polar functional groups. The synthesis was carried out by graft copolymerization reaction of N,N‐dimethylaminoethylmethacrylate with methacrylic acid onto wood pulp. The preparation conditions at which the grafting process proceeds homogeneously are determined. Characterization and some selected properties of the original and grafted wood pulp were evaluated using FTIR and scanning electron microscope, also, the removal of phenol, benzene, and toluene on laboratory scale was investigated by using gas chromatography. It was found that phenol shows the highest removal percent than that of benzene and toluene. The efficiency of removal of the nonionic contaminants is found to be 97%, which shows a great promise for its applicability in the removal of organic contaminates from wastewater. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3589–3595, 2006
Preparation and characterization of novel cationic copolymer hydrogels with pH sensitivity and thermosensitivity
Authors: Guo Jin Tang , Li Ling , Li Xiong Yong , Zhu Jun Li
Published: March 2006

Cationic hydrogels were synthesized through the copolymerization of N‐isopropylacrylamide and dimethylaminoethylmethacrylate. N,N′‐Methylenebisacrylamide was used as a crosslinking agent, and sodium bisulfite/ammonium persulfate was used as an initiator. The equilibrium and dynamic swelling properties were investigated to reveal the pH sensitivity and thermosensitivity of the hydrogels. The conclusion was drawn that the prepared cationic hydrogels demonstrated critical sensitivity at 37°C and pH 7.0–8.0 and that the stronger the acidity was of the buffered solution, the shorter the equilibrium swelling time was of the hydrogels. Drug‐release experiments in vitro were carried out at 37°C (close to body temperature), at pH 1.4 (close to the pH of the stomach), and at pH 7.4 (close to the pH of the intestine). The release results indicated that the drug (chloramphenicol) was released more rapidly from the prepared hydrogel in a pH 1.4 buffered solution than in a pH 7.4 one, and this was consistent with the results predicted from the experiments of the swelling kinetics. Moreover, the drug‐release process was confirmed by scanning electron micrographs of the hydrogels embedded with chloramphenicol. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3602–3608, 2006
Microstructure and wear properties of plasma‐sprayed aluminum–silicon–polyester coatings
Authors: Öksüz Mustafa , Yıldırım Hüseyin , Erturan Seyfettin
Published: March 2006

Powder coatings, which are made by plasma‐spraying processes, are being used in industrial applications because of their wear resistance, chemical resistance, and high impact strength even at low service temperatures. These factors increase the importance of plastic and plastic‐based coatings in industrial applications. In this study, an aluminum–silicon–polyester‐based composite coating was applied by plasma‐spraying processes with and without an intermediate bond coat (Ni–Al). The effects of the coating thickness, intermediate bond coat, and processes parameters on the microstructure and wear properties of the coating were studied experimentally. The wear properties of the coatings were determined according to ball‐on‐disk procedure. The microstructures of the coating were examined by optical microscopy and scanning electron microscopy. The results indicated that the plasma‐spraying current and thickness had a strong influence on the wear resistance and microstructural properties of the aluminum–silicon–polyester coating. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3609–3614, 2006
Thermal and surface characterization of plasticized starch polyvinyl alcohol blends crosslinked with epichlorohydrin
Authors: Sreedhar B. , Chattopadhyay D. K. , Karunakar M. Sri Hari , Sastry A. R. K.
Published: March 2006

Starch‐polyvinyl alcohol (PVA) blends in 2:8 wt % were prepared with various plasticizers such as polyethylene glycol (PEG‐200, PEG‐400) and glycerol. The crosslinking of starch‐PVA blends by epichlorohydrin was carried out in the presence of a plasticizer in situ. The obtained films were analyzed by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), dynamic mechanical and thermal analysis (DMTA), and X‐ray photoelectron spectroscopy (XPS), and remarkable changes in thermal stability and glass‐transition temperature have been observed on plasticizing and crosslinking in different concentrations. Different kinetic models such as Coats–Redfern, Broido, Friedman, and Chang were used to calculate the kinetic parameters of thermal decomposition. The results suggest that the thermal stability and activation energy of thermal decomposition passes through maxima at a critical concentration of plasticizer and increases with increasing crosslinker concentration. High‐resolution C 1s XPS analysis was used to provide a method of differentiating the presence of various carbons associated with different environment in the films. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 25–34, 2006
Preparation of copolymer of L‐aspartic acid and L‐glutamic acid
Authors: Rui Zhang , Tianwei Tan
Published: March 2006

In this article, a new copolymer of L‐aspartic acid and L‐glutamic acid, which may be a biodegradable high molecular polymer and can be used more widely in many areas, was synthesized. The conditions of preparation, such as catalyst, reaction time, reaction temperature, the amount of catalyst, the times of adding catalyst, and the molar ratio of L‐aspartic acid to L‐glutamic acid, were optimized. The copolymer was characterized by 13C NMR, infrared spectroscopy, and X‐ray diffractometer. The molecular weight was determined by GPC. The result indicated that production yield, purity of product, and molecular weight of product increased with amount of catalyst and molar ratio of L‐aspartic acid to L‐glutamic acid increasing. The best condition of preparation was the following: reacting 2–4 h at the temperature of 180–200°C. The product yield with the molecular weight 13,000.00 reached 63.2% and the purity of product was 96.33% when the copolymerization was carried out at the temperature of 200°C under vacuum for 2 h. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3626–3633, 2006
Mechanical properties of composites from sawdust and recycled plastics
Authors: Najafi Saeed Kazemi , Hamidinia Elham , Tajvidi Mehdi
Published: March 2006

Mechanical properties of wood plastic composites (WPCs) manufactured from sawdust and virgin and/or recycled plastics, namely high density polyethylene (HDPE) and polypropylene (PP), were studied. Sawdust was prepared from beech industrial sawdust by screening to the desired particle size and was mixed with different virgin or recycled plastics at 50% by weight fiber loading. The mixed materials were then compression molded into panels. Flexural and tensile properties and impact strength of the manufactured WPCs were determined according to the relevant standard specifications. Although composites containing PP (virgin and recycled) exhibited higher stiffness and strength than those made from HDPE (virgin and recycled), they had lower unnotched impact strengths. Mechanical properties of specimens containing recycled plastics (HDPE and PP) were statistically similar and comparable to those of composites made from virgin plastics. This was considered as a possibility to expand the use of recycled plastics in the manufacture of WPCs. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3641–3645, 2006
Rheological properties of high melt strength poly(ethylene terephthalate) formed by reactive extrusion
Authors: Forsythe J. S. , Cheah K. , Nisbet D. R. , Gupta R. K. , Lau A. , Donovan A. R. , O'Shea M. S. , Moad G.
Published: March 2006

A reactive extrusion process was developed improving the rheological properties of PET via the coaddition of a dianhydride and polyol. Specifically, the coaddition of pyromellitic dianhydride (PMDA) with pentaerythritol resulted in a gel‐free polyester with superior melt strengths and viscosities compared to the addition of PMDA alone. The enhancement in rheological properties were dependent on the relative amounts of dianhydride and polyol with the resultant polyester structurally stable in the melt. These results are consistent with the formation of a hyperbranched polyester with long chain branches. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3646–3652, 2006
Preparation and properties of nanocomposite hydrogels containing silver nanoparticles by ex situ polymerization
Authors: Lee Wen‐Fu , Tsao Kai‐Tai
Published: March 2006

A series of composite hydrogels containing silver nanoparticle used for bioadhesives were prepared from acrylic acid, poly(ethylene glycol) methyl ether acrylate, and silver nanoparticles through ex situ polymerization. Silver nanoparticles with a narrow size distribution were prepared by the reduction of a silver nitrate solution with ascorbic acid. The influence of the content of the silver nanoparticles in the hydrogels on the equilibrium swelling ratio, mechanical properties, electrical conductivity, and inactivation of Escherichia coli (E. coli) was investigated in this study. The results showed that the swelling ratios of the composite gels were reduced by silver nanoparticles in the gels but were not reduced with an increase in the content of silver nanoparticles. In addition, the crosslinking density and shear modulus of these hydrogels did not increase with an increase in the content of silver nanoparticles. The adhesive force of these hydrogels (the APECAg series) was not obviously changed. Finally, the initial rate of E. coli inactivation for the APECAg series hydrogels showed excellent antibacterial properties. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3653–3661, 2006