bluuebunny/crossref_metadata_2025 huggingface dataset:
In vitro blood compatibility of modified PDMS surfaces as superhydrophobic and superhydrophilic materials
Authors: Khorasani M. T. , Mirzadeh H.
Published: December 2003

The surface of polydimethylsiloxane rubber (PDMS) was irradiated by a CO2‐pulsed laser. The irradiated surfaces were grafted by hydroxyethylmethacrylate phosphatidylcholine (HEMAPC) by using the preirradiation method. The laser‐treated surfaces and HEMAPC‐grafted PDMS surfaces were characterized by using a variety of techniques including ATR‐FTIR spectroscopy, scanning electron microscopy (SEM), and wettability, which was measured by a water‐drop contact angle. Different surfaces with different wettability were prepared. These surfaces, including untreated PDMS (hydrophobic), laser‐treated PDMS (superhydrophobic), and HEMAPC‐grafted surfaces (superhydrophilic), were used for a platelet adhesion study. Results from in vitro testing indicated that chemical structures, such as negative‐charge polar groups and wettability, are important factors in blood compatibility of these surfaces and the superhydrophilic (the most wettable) and the superhydrophobic (the most unwettable) of modified PDMS surfaces have excellent blood compatibility compared to the unmodified PDMS. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:2042–2047, 2004
Single component self‐curable aqueous‐based PU system with new aziridinyl curing agent
Authors: Lai Jian‐Zei , Chang Yu‐Ching , Yeh Jen‐Taut , Chen Kan‐Nan
Published: December 2003

The self‐emulsified aqueous‐based polyurethane (PU) consists of carboxyl group, which is an ionic center not only stabilizing the aqueous polymer dispersion but also serving as the curing site toward aziridinyl curing agent. Two new aziridinyl curing agents, HDI‐AZ and ADA‐AZ, are prepared from an addition reaction of aziridine to hexamethylene diisocyanate (HDI) and adipic acyl chloride (ADA), respectively. These curing agents are added separately into NCO‐terminated PU prepolymer before or after the water dispersion process. The resulting PU dispersion becomes a single component self‐curable aqueous‐based PU system. The cured PU is obtained from this single component PU dispersion on drying at ambient temperature. The improved PU properties demonstrate the feasibility of this convenient single component self‐curable aqueous‐based PU system. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91:1997–2007, 2004
Thermal and mechanical properties of poly(butylene succinate) nanocomposites with various organo‐modified montmorillonites
Authors: Someya Yoshihiro , Nakazato Toshiyuki , Teramoto Naozumi , Shibata Mitsuhiro
Published: December 2003

Nanocomposites based on biodegradable poly(butylene succinate) (PBS) and layered silicates were prepared by melt intercalation. Nonmodified montmorillonite (MMT) and MMTs (DA‐M, ODA‐M, ALA‐M, LEA‐M, and HEA‐M) organo‐modified by protonated ammonium cations {i.e., those of dodecylamine, octadecylamine, 12‐aminolauric acid, N‐lauryldiethanolamine, and 1‐[N,N‐bis(2‐hydroxyethyl)amino]‐2‐propanol, respectively} were used as layered silicates. From morphological studies using transmission electron microscopy, DA‐M, ODA‐M, and LEA‐M were found to be dispersed homogeneously in the matrix polymer, whereas some clusters or agglomerated particles were observed for ALA‐M, HEA‐M, and MMT. The enlargement of the difference in the interlayer spacing between the clay and PBS/clay composite, as measured by X‐ray diffraction, had a good correlation with the improvement of the clay dispersion and with the increase in the tensile modulus and the decrease in the tensile strength of the PBS composites with an inorganic concentration of 3 wt %. Dynamic viscoelastic measurements of the PBS/LEA‐M nanocomposite revealed that the storage modulus and glass‐transition temperature increased with the inorganic concentration (3–10 wt %). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1463–1475, 2004
Milling‐induced esterification between cellulose and maleated polypropylene
Authors: Qiu Wulin , Zhang Farao , Endo Takashi , Hirotsu Takahiro
Published: December 2003

The ball milling of cellulose and maleic anhydride grafted polypropylene (MAPP) induced the formation of ester bonds between OH groups of cellulose and maleic anhydride groups of MAPP, in marked contrast to the melt mixing of the original cellulose and MAPP, through which the esterification was hardly observed. This esterification was hardly dependent on the chemical structure of MAPP. In agreement with the enhanced interfacial adhesion due to the formation of ester bonds, a composite prepared via ball milling revealed an improvement in the tensile strength with respect to a melt‐mixed composite. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1703–1709, 2004
Direct measurement of gas solubilities in polymers with a high‐pressure microbalance
Authors: Von Solms N. , Nielsen J. K. , Hassager O. , Rubin A. , Dandekar A. Y. , Andersen S. I. , Stenby E. H.
Published: December 2003

Solubility and diffusion data are presented for methane and carbon dioxide gases in high‐density polyethylene. The polymer was cut from extruded piping intended for use in offshore oil and gas applications. The measurements were carried out with a high‐pressure microbalance. The properties were determined from 25 to 50°C and from 50 to 150 bar for methane and from 20 to 40 bar for carbon dioxide. In general, a good agreement was obtained with similar measurements reported in the literature. The solubility followed Henry's law (linear) dependence with pressure, except at high pressures for methane, for which negative deviations from Henry's law behavior were observed. The diffusion coefficients for each of the gases in the polymer were also measured with the balance, although the uncertainty was greater than for the solubility measurements. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1476–1488, 2004
Physical properties of polycaproamide/cationic dyeable poly(ethylene terephthalate) polyblended fibers
Authors: Hsiao Keven , Tsen Wen‐Chin , Shu Yao‐Chi
Published: December 2003

Polycaproamide (PCA) and cationic dyeable poly(ethylene terephthalate) (CDP) polymers were blended mechanically (in ratios of 75/25, 50/50, and 25/75) in a melt twin‐screw extruder to prepare three PCA/CDP polyblended materials. The blends of PCA and CDP were spun into fibers. The molar ratio of dimethyl 5‐sulfoisophthalate sodium salt for CDP was 2%. This study investigated the physical properties of PCA/CDP polyblended fibers with nuclear magnetic resonance, gel permeation chromatography, gas chromatography, potentiometer, differential scanning calorimetry (DSC), thermogravimetric analysis, scanning electron microscopy (SEM), extension stress–strain measurements, density gradient analysis, and rheometry. The experimental results of DSC proved that PCA and CDP formed an immiscible system. In an SEM image of a 50/50 PCA/CDP blend, the morphological aggregation of a larger size, from 3 to 5 μm in diameter, was observed. The rheological behavior of the PCA/CDP polyblended materials exhibited negative‐deviation blends, and the 50/50 blend of the PCA/CDP polyblended fibers showed a minimum tenacity value. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1710–1715, 2004
Synthesis of isobutyl maleate–divinylbenzene microspheres by different techniques of heterogeneous polymerizations
Authors: Gawdzik Barbara , Maciejewska Malgorzata
Published: December 2003

Copolymers of isobutyl maleate–divinylbenzene in the form of microspheres were obtained. In their preparation, the following techniques of heterogeneous polymerization were used: emulsion, modified emulsion, precipitation, suspension, and multistep swelling polymerization. Among the obtained microspheres, those synthesized by modified emulsion and multistep swelling polymerizations have a size suitable for HPLC purposes, whereas the product of suspension polymerization can be used as packing material for gas chromatography. Their porous structure was studied in detail. The influence of the polymerization technique on the particle size and morphology is discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2008–2015, 2004
Maleic anhydride grafted thermoplastic elastomer as an interfacial modifier for polypropylene/polyamide 6 blends
Authors: Ou Yuchun , Lei Yuguo , Fang Xiaoping , Yang Guisheng
Published: December 2003

A maleic anhydride grafted thermoplastic elastomer (TPEg) was prepared. The effect of the TPEg on the morphology and performance of polypropylene (PP)/polyamide 6 (PA‐6) blends was studied. The final properties of the blends were tuned through variations in the TPEg/PA‐6 ratios and TPEg and PA‐6 percentages in the blends. Scanning electron micrographs showed that the TPEg greatly improved the homogeneity of the blends, and this led to better mechanical performance. The nonisothermal crystallization behaviors of PP and PA‐6 in the blends, revealed by differential scanning calorimetry, were different from those of pure PP and PA‐6. The crystallization temperature and rate of PP were promoted by the PA‐6 component because of its nucleating effect, whereas stepwise crystallization was detected for PA‐6 in the PP/PA‐6 blends when the TPEg was added. On the basis of these observations, a schematic model was proposed for these blends. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1806–1815, 2004
Grafting, blending, and biodegradability of cellulose acetate
Authors: Guruprasad K. H. , Shashidhara G. M.
Published: December 2003

We performed the graft copolymerization of methyl acrylate and methyl methacrylate on cellulose acetate (CA) by a free‐radical method. The grafting was confirmed by gravimetric analysis and IR spectroscopy. Low graft efficiency was observed for the benzoyl peroxide initiator used in the system. Melt blending of CA and nylon 6 was done for CA‐rich compositions. The physical and mechanical property measurements showed an improvement over virgin CA properties. The chemical properties, however, did not show any phenomenal advancement. A CA/starch (90/10) blend was prepared and studied for biodegradation during soil burial. The gravimetric and mechanical property results indicated possible degradation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1716–1723, 2004
Radiation grafting/crosslinking of silk using electron‐beam irradiation
Authors: Liu Jinqiang , Shao Jianzhong , Zheng Jinhuan
Published: December 2003

The radiation grafting of silk with methacrylamide (MAA) was studied using an electron‐beam (EB) irradiation technique. Two irradiation processes, preirradiation and coirradiation, were compared, and some factors affecting the degree of grafting were investigated. The radiation crosslinking of silk with dimethyloldihydroxyethylene urea (DMDHEU) was preliminarily studied. The physical and mechanical properties such as whiteness, breaking strength, and resilience of the radiation‐grafted/crosslinked silk fabrics were examined. The radiation grafting of silk with MAA increases the silk weight, while the radiation crosslinking of silk with DMDHEU imparts improved crease resistance to silk. X‐ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) analysis indicate the formation of peroxy and free‐radical species on the EB‐irradiated silk. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2028–2034, 2004
Use of compatible blends to fabricate carbon black composite vapor detectors
Authors: Penco Maurizio , Sartore Luciana , Bignotti Fabio , Sciucca Stefania Della , Ferrari Vittorio , Crescini Paolo , D'Antone Salvatore
Published: December 2003

The aim of this work was the development of materials to be used in the field of gas sensing for the detection of organic vapors. Conductive sensors were prepared with carbon black filled blends of poly(vinyl chloride) and diol‐terminated poly(ϵ‐caprolactone), an oligomeric plasticizer. For comparison, blends with di(2‐ethylhexyl)phthalate, a traditional low‐molecular‐weight plasticizer, were also prepared. All sensors were tested upon exposure to different organic vapors. In general, the plasticizer content affected the response rates of the sensors, and a linear variation of the relative resistance with the analyte concentration was observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1816–1821, 2004
Study of the effect of branch content of octene‐based linear low‐density polyethylene on its melt miscibility with high‐density polyethylene by inverse gas chromatography
Authors: Zhao Liyan , Choi Phillip
Published: December 2003

Inverse gas chromatography was used to measure Flory–Huggins interaction parameters (χ23) for five binary blends consisting of high‐density polyethylene (HDPE) and octene‐based linear low‐density polyethylene (LLDPE) with different compositions at four elevated temperatures. The branch content of the LLDPE used in each pair of the blends ranged from 2 to 87 branches per 1000 backbone carbons. To obtain solvent‐independent χ23, the data analysis approach recently proposed by Zhao and Choi (Polymer 2001, 42, 1075) was used. The results indicate that the higher the branch content of LLDPE, the higher the measured χ23, signifying that HDPE/LLDPE blends with low branch content LLDPEs are relatively more miscible than those with high branch contents. In particular, when the branch content of LLDPE is higher than 50 branches per 1000 backbone carbons, phase separation may occur. This result is in good agreement with other researchers' results obtained from different techniques. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1927–1931, 2004
Kinetic features of the nonisothermal oxidative degradation of ethylene vinyl acetate copolymers
Authors: Ruban L. V. , Sychugova O. V. , Kolesnikova N. N. , Zaikov G. E.
Published: December 2003

Thermogravimetric analysis was used for a comparative investigation of the thermooxidative decomposition of ethylene vinyl acetate (EVA) copolymers with different vinyl acetate (VA) group contents. There were two stages of mass loss in this process. It was revealed that the apparent activation energies were correlated with the content of VA groups in the EVA copolymers. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1958–1961, 2004
Effect of poly(vinylidene fluoride) interface layer on charge storage and residual potential in amorphous selenium films
Authors: Chand S. , Sharma G. D. , Dwivedi S. , Chandra R.
Published: December 2003

Thermally stimulated discharge current and the potential decay behavior of amorphous selenium (a‐Se) films (∼ 100 μm thick) were studied as a function of the thickness of a poly(vinylidene fluoride) (PVDF) interface barrier layer in the range 2000–8000 Å. The incorporation of a PVDF layer into an a‐Se film resulted in (1) a considerable reduction in its charge storage capacity, (2) a considerable increase in its initial surface potential, and (3) a considerable reduction in its residual potential and the enhancement of its X‐ray sensitivity. These effects were attributed to the blocking and field‐enhanced mobility role of the PVDF interface barrier layer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1962–1966, 2004
Instantaneous elastic recovery of poly(trimethylene terephthalate) filament
Authors: Chen Kequan , Tang Xiaozhen
Published: December 2003

The instantaneous elastic recoveries of poly(trimethylene terephthalate) (PTT), PET, and PBT filaments were comparatively analyzed by a tensile testing machine. The conditions of the measurement were studied and the mechanism of instantaneous elastic recovery of these three aromatic polyester filaments is discussed. The instantaneous elastic recovery of PTT filaments was significantly higher than those of PBT and PET filaments. Moreover, PTT filaments had a high instantaneous elastic recovery even at a high elongation of 20%. The outstanding instantaneous elastic recovery of PTT filaments resulted from its helical conformation in crystal lattice, which responded immediately to the applied stress and deformed as though it was a coiled spring; we suggest it was a quasispring elastic recovery mechanism. When we measured the instantaneous elastic recovery of, PTT filaments with the tensile testing machine, it was appropriate to set up the crosshead speed at 500 mm/min with an elongation of 20% and a load of 0.5 cN/tex. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 1967–1975, 2004
Methyl methacrylate/N‐(o‐/m‐/p‐chlorophenyl) itaconimide copolymers: Microstructure determination by NMR spectroscopy
Authors: Anand Vishal , Kumar Rajeev , Choudhary Veena
Published: December 2003

Homopolymerization and copolymerization of N‐(o‐/m‐/p‐chlorophenyl) itaconimide with methyl methacrylate was carried out by taking varying mole fractions (0.1 to 0.5) of N‐aryl substituted itaconimide monomers in the initial feed using azobisisobutyronitrile as an initiator and tetrahydrofuran as the solvent. The copolymer composition was determined by 1H‐NMR spectroscopy using the ratio of proton resonance signal intensity attributed to OCH3 of MMA (δ = 3.5–3.8 ppm) and the aromatic protons (δ = 7.0–7.5 ppm) of N‐(o‐/m‐/p‐chlorophenyl) itaconimide. The comonomer reactivity ratios were determined using Kelen–Tüdos and nonlinear error in variable methods. The reactivity ratios obtained by nonlinear error in variable methods were r1 (PI) = 1.26/r2 (MMA) = 0.35; r1 (MI) = 1.21/r2 (MMA) = 0.34; and r1 (OI) = 0.78/r2 (MMA) = 0.34. The carbonyl carbon signals of MMA (M) as well as N‐aryl itaconimide (I) copolymers were used for the determination of the sequence distribution of M‐ and I‐centered triads. The sequence distribution of M‐ and I‐centered triads determined from 13C{1H}‐NMR spectra of the copolymers are in good agreement with the triad concentrations calculated using the Alfrey–Mayo statistical model and Monte Carlo simulation method. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2016–2027, 2004
Mapping information policy frames: The politics of the digital millennium copyright act
Authors: Maxwell Terrence A.
Published: December 2003

Passage of the Digital Millennium Copyright Act (DMCA) was a significant milestone in congressional information policy legislation. However, the results were widely criticized in some circles as providing too much power to certain stakeholder groups. This paper uses computer‐based content analysis and a theoretical taxonomy of information policy values to analyze congressional hearing testimony. The results of document coding were then analyzed using a variety of statistical tools to map how different stakeholders framed issues in the debate and determine if congressional value statements about the legislation conformed more closely to certain stakeholders. Results of the analysis indicate that significant differences in the use of information policy terms occurred across stakeholders, and showed varying degrees of convergence between congressional or other stakeholders when framing information policy issues.
Localization in Modern Standard Arabic
Authors: Abdelali Ahmed
Published: December 2003

Modern Standard Arabic (MSA) is the official language used in all Arabic countries. In this paper we describe an investigation of the uniformity of MSA across different countries. Many studies have been carried out locally or regionally on Arabic and its dialects. Here we look on a more global scale by studying language variations between countries. The source material used in this investigation was derived from national newspapers available on the Web, which provided samples of common media usage in each country. This corpus has been used to investigate the lexical characteristics of Modern Standard Arabic as found in 10 different Arabic speaking countries. We describe our collection methods, the types of lexical analysis performed, and the results of our investigations. With respect to newspaper articles, MSA seems to be very uniform across all the countries included in the study, but we have detected various types of differences, with implications for computational processing of MSA.
Spatialization of Web sites using a weighted frequency model of navigation data
Authors: Reitsma René F. , Thabane Lehana , MacLeod J. Michael B.
Published: December 2003

A common problem in the spatialization of information systems is the determination of geometry; i.e., dimensionality and metric. Such geometry is either chosen a priori or is inferred a posteriori from secondary data. Recent work emphasizes the use of geometric information latent in a system's navigational record. Resolving this information from its noisy background, however, requires an unambiguous criterion of selection. In this paper we use a previously published, statistical method for resolving a Web‐based information system's geometry from navigational data. However, because of the method's (theoretical) sensitivity to data selection, a weighted frequency correction based on empirical probability distributions is applied. The effect of this correction on the Web‐space geometry is investigated. Results indicate that the inferred geometry is robust; i.e., it does not significantly change under this probabilistic correction.
Catalogers' common ground and shared knowledge
Authors: Šauperl Alenka
Published: December 2003

The problem of multiple interpretations of meaning in the indexing process has been mostly avoided by information scientists. Among the few who have addressed this question are Clare Beghtol and Jens Erik Mai. Their findings and findings of other researchers in the area of information science, social psychology, and psycholinguistics indicate that the source of the problem might lie in the background and culture of each indexer or cataloger. Are the catalogers aware of the problem? A general model of the indexing process was developed from observations and interviews of 12 catalogers in three American academic libraries. The model is illustrated with a hypothetical cataloger's process. The study with catalogers revealed that catalogers are aware of the author's, the user's, and their own meaning, but do not try to accommodate them all. On the other hand, they make every effort to build common ground with catalog users by studying documents related to the document being cataloged, and by considering catalog records and subject headings related to the subject identified in the document being cataloged. They try to build common ground with other catalogers by using cataloging tools and by inferring unstated rules of cataloging from examples in the catalogs.
The real stakes of virtual publishing: The transformation of E‐Biomed into PubMed central
Authors: Kling Rob , Spector Lisa B. , Fortuna Joanna
Published: December 2003

In May 1999, National Institutes of Health (NIH) Director Harold Varmus proposed an electronic repository for biomedical research literature server called “E‐biomed.” E‐biomed reflected the visions of scholarly electronic publishing advocates: It would be fully searchable, be free to readers, and contain full‐text versions of both preprint and postpublication biomedical research articles. However, within 4 months, the E‐biomed proposal was radically transformed: The preprint section was eliminated, delays were instituted between article publication and posting to the archive, and the name was changed to “PubMed Central.” This case study examines the remarkable transformation of the E‐biomed proposal to PubMed Central by analyzing comments about the proposal that were posted to an online E‐biomed forum created by the NIH, and discussions that took place in other face‐to‐face forums where E‐biomed deliberations took place. We find that the transformation of the E‐biomed proposal into PubMed Central was the result of highly visible and highly influential position statements made by scientific societies against the proposal. The literature about scholarly electronic publishing usually emphasizes a binary conflict between (trade) publishers and scholars/scientists. We conclude that: (1) scientific societies and the individual scientists they represent do not always have identical interests in regard to scientific e‐publishing; (2) stakeholder politics and personal interests reign supreme in e‐publishing debates, even in a supposedly status‐free online forum; and (3) multiple communication forums must be considered in examinations of e‐publishing deliberations.
Non‐word identification or spell checking without a dictionary
Authors: Comeau Donald C. , Wilbur W. John
Published: December 2003

MEDLINE® is a collection of more than 12 million references and abstracts covering recent life science literature. With its continued growth and cutting‐edge terminology, spell‐checking with a traditional lexicon based approach requires significant additional manual follow‐up. In this work, an internal corpus based context quality rating α, frequency, and simple misspelling transformations are used to rank words from most likely to be misspellings to least likely. Eleven‐point average precisions of 0.891 have been achieved within a class of 42,340 all alphabetic words having an α score less than 10. Our models predict that 16,274 or 38% of these words are misspellings. Based on test data, this result has a recall of 79% and a precision of 86%. In other words, spell checking can be done by statistics instead of with a dictionary. As an application we examine the time history of low α words in MEDLINE® titles and abstracts.
Do the Web sites of higher rated scholars have significantly more online impact?
Authors: Thelwall Mike , Harries Gareth
Published: December 2003

The quality and impact of academic Web sites is of interest to many audiences, including the scholars who use them and Web educators who need to identify best practice. Several large‐scale European Union research projects have been funded to build new indicators for online scientific activity, reflecting recognition of the importance of the Web for scholarly communication. In this paper we address the key question of whether higher rated scholars produce higher impact Web sites, using the United Kingdom as a case study and measuring scholars' quality in terms of university‐wide average research ratings. Methodological issues concerning the measurement of the online impact are discussed, leading to the adoption of counts of links to a university's constituent single domain Web sites from an aggregated counting metric. The findings suggest that universities with higher rated scholars produce significantly more Web content but with a similar average online impact. Higher rated scholars therefore attract more total links from their peers, but only by being more prolific, refuting earlier suggestions. It can be surmised that general Web publications are very different from scholarly journal articles and conference papers, for which scholarly quality does associate with citation impact. This has important implications for the construction of new Web indicators, for example that online impact should not be used to assess the quality of small groups of scholars, even within a single discipline.
An experiment using coordinate title word searches
Authors: Kilgour Frederick G.
Published: December 2003

This study, the fourth and last of a series designed to produce new information to improve retrievability of books in libraries, explores the effectiveness of retrieving a known‐item book using words from titles only. From daily printouts of circulation records at the Walter Royal Davis Library of the University of North Carolina at Chapel Hill, 749 titles were taken and then searched on the 4‐million entry catalog at the library of the University of Michigan. The principal finding was that searches produced titles having personal authors 81.4% of the time and anonymous titles 91.5% of the time; these figures are 15 and 5%, respectively, lower than the lowest findings presented in the previous three articles of this series (Kilgour,1995;1997;2001).
Topically applied minoxidil may cause fetal malformation: A case report
Authors: Smorlesi Carlo , Caldarella Adele , Caramelli Laura , Di Lollo Simonetta , Moroni Flavio
Published: December 2003

BACKGROUND

Minoxidil is a K+ channel opener able to cause relaxation of vascular smooth muscles and modify cell growth and cell fate or migration. It is now widely used for its hair growth promoting effects. When locally applied, it is absorbed through the skin and may have systemic pharmacological effects.

CASE

A 28‐year‐old white pregnant woman daily applied minoxidil 2% to her scalp because of hair loss. At the 22nd gestational week, after a routine ultrasound test showing significant brain, heart, and vascular malformations of the fetus, pregnancy was interrupted. The placenta had numerous ischemic areas and a discrepancy between gestational age and villi maturation. In the villi, capillaries were increased in number, significantly enlarged, and excessively marginalized. The fetus' heart was increased in volume and had a globose shape, the aorta had a distal stenosis. The sigmoid colon was significantly increased in length and a mesentery commune was present. The brain had enlarged ventricles and abundant hemorrhages. Histological examination showed areas of demyelinization with gliosis, signs of excessive and inappropriate angiogenesis, and capillary rearrangement.

CONCLUSIONS

Further knowledge on minoxidil‐induced fetal toxicity would be beneficial before allowing its use in pregnant women. Birth Defects Research (Part A), 2003. © 2003 Wiley‐Liss, Inc.
New case of non‐mosaic tetrasomy 9p in a severely polymalformed newborn girl
Authors: De Azevedo Moreira Lília Maria , Freitas Lucy Magalhães , Gusmão Fábio Alexandre Ferreira , Riegel Mariluce
Published: December 2003

BACKGROUND

The phenotypic expression of an additional chromosome 9 causes a very broad clinical spectrum of anomalies. The prognosis for infants with non‐mosaic tetrasomy 9p is poor, and they usually die at a very early age.

CASE

In this article we present a new case of complete tetrasomy 9p in a newborn girl with multiple dysmorphologic features. Cytogenetic studies were carried out by CBG, GTG, and QFQ chromosome bandings, as well as by fluorescence in situ hybridization (FISH). The cytogenetic findings for the newborn girl showed an extra chromosome interpreted as an isochromosome 9p. The karyotype was characterized as 47,XX,+mar.ish i(9)(p10)(wcp9+). The parental chromosomes were normal.

CONCLUSIONS

The karyotype and clinical features of the newborn girl (e.g., typical craniofacial dysmorphism, severe skeletal anomalies, and visceral and genito‐urinary malformations), compared with cases reported in the literature, give additional support to a clinical definition of this chromosomal syndrome. Birth Defects Research (Part A), 2003. © 2003 Wiley‐Liss, Inc.
Method of weighted proportion of reproductive‐aged women taking folic acid supplements to predict a neural tube defect rate decline
Authors: Yang Quanhe , Atkinson Michael , Erickson J. David
Published: December 2003

BACKGROUND

Neural tube defect (NTD) rates can be lowered by increased consumption of folic acid (FA) by women before and during early pregnancy. The crude proportion of reproductive‐aged women taking FA supplements has been used to predict a decline of the NTD rate in the general population. In this study we examine the potential error in using the crude proportion to predict NTD risk reduction, and offer an alternative method.

METHODS

The crude proportion measures the number of women taking FA. It ignores the substantial variability by maternal age in the probability of giving birth. Age‐specific fertility rates (ASFRs) reflect the probability that a woman in a specific age group will give birth in a given year. In this study, we show how to calculate a proportion weighted by ASFRs to predict a decline in the NTD rate, and to assess the effectiveness of FA consumption in preventing NTDs.

RESULTS

Our results show that a crude proportion of 50% of women (15–49 years old) taking FA is associated with a range of 24–77% in weighted proportions. Assuming a 40% risk reduction from taking 400 μg of FA daily, the expected NTD rate decline could vary from 9.6% to 30.6%, depending on the age distribution of women taking FA.

CONCLUSIONS

The ASFR‐weighted proportion estimates the proportion of babies born to women taking FA, as opposed to the crude proportion of women taking FA. We recommend using the ASFR‐weighted proportion to predict an NTD rate decline and measure the success of FA education campaigns. We found that when women in high‐fertility age groups increased their FA consumption, the decline in the NTD rate was greater than when women in low‐fertility age groups did so. Our findings suggest that the more efficient approach to NTD prevention is to focus on women with a higher probability of giving birth. For example, by focusing on <50% of women of childbearing age (20–34 years), as much as 76% of the maximum NTD rate reduction can be achieved. Birth Defects Research (Part A), 2003. Published 2003 Wiley‐Liss, Inc.
Differential risks to males and females for congenital malformations among 2.5 million California births, 1989–1997
Authors: Shaw Gary M. , Carmichael Suzan L. , Kaidarova Zhanna , Harris John A.
Published: December 2003

BACKGROUND

Although many studies have observed variations in the prevalence of specific malformations by sex, there is a lack of population‐based data on potential malformation prevalence differences by sex at birth.

METHODS

Our objective was to explore differences in the prevalence of structural congenital malformation phenotypes between sexes in a California population of 2.5 million live‐ and stillbirths, using data from a population‐based active surveillance system. Ascertainment was performed among offspring of California women who delivered in nonmilitary hospitals during the period of 1989–1997. Malformations were grouped according to the four‐digit malformation codes of the British Pediatric Association.

RESULTS

Overall, 32,619 males and 21,835 females were considered to have structural congenital malformations, with prevalences of 2.52% and 1.76%, respectively. Thus, males demonstrated a malformation prevalence that was 22% higher than that in females. Using a criterion of a 40% increase or decrease in the relative risk for males, increased risks for 15 and decreased risks for 17 specific malformation categories were observed. Increased risks were associated with most organ systems, with the notable exception of the nervous system (increased risks for nervous system malformations were observed among female births). Risks were not substantially influenced by adjusting for maternal age, race/ethnicity, parity, or education.

CONCLUSIONS

Our observations extend the relatively few studies that have investigated differential prevalences of a large number of specific structural malformations between male and female births. Birth Defects Research (Part A) 67:000–000, 2003. © 2003 Wiley‐Liss, Inc.
Phenotype of the neural tube defect mouse model bent tail is not sensitive to maternal folinic acid, myo‐inositol, or zinc supplementation
Authors: Franke Barbara , Klootwijk Riko , Lemmers Bianca , De Kovel Carolien G.F. , Steegers‐Theunissen Regine P.M. , Mariman Edwin C.M.
Published: December 2003

BACKGROUND

Bent tail is a mouse model for X‐linked neural tube defects (NTDs) that is characterized by the presence of exencephaly, a delayed posterior neuropore closure, and a tail phenotype. In addition, Bent tail shows laterality defects and increased prenatal mortality. The congenital malformations of this mouse are caused by a submicroscopic deletion that completely encompasses the gene coding for the zinc finger transcription factor Zic3. In this study we investigated the sensitivity of the phenotype of Bent tail to the nutrients folinic acid, myo‐inositol, and zinc. These nutrients are thought to be involved in the etiology of NTDs, in combination with a genetic predisposition.

METHODS

The most penetrant phenotype of the Bent tail mouse, the tail malformation, was used as a marker for the nutrient sensitivity of the neural phenotype. The size of the litters and the survival of the offspring, subdivided according to genotype, were analyzed as markers for the nutrient sensitivity of other phenotypic features of Bent tail.

RESULTS

In confirmation of earlier studies, we observed the prenatal loss of a number of homozygous females and hemizygous males, as well as the effect of genotype on the tail phenotype of Bent tail. However, periconceptional supplementation of the maternal diet with folinic acid, myo‐inositol, or zinc produced no significant effects on either the tail phenotype of the offspring or the size and genotypic composition of the litters.

CONCLUSIONS

Bent tail appears to be a folinic acid‐, myo‐inositol‐, and zinc‐insensitive mouse model for NTDs. Birth Defects Research (Part A), 2003. © 2003 Wiley‐Liss, Inc.
First trimester exposure to corticosteroids and oral clefts
Authors: Pradat Pierre , Robert‐Gnansia Elisabeth , Di Tanna Gian Luca , Rosano Aldo , Lisi Alessandra , Mastroiacovo Pierpaolo ,   all contributors to the MADRE database
Published: December 2003

BACKGROUND

The possible association between oral cleft in the newborn and maternal exposure to corticoids during pregnancy is still controversial. The aim of this study was to test this association by a case‐control analysis using the large multicentric MADRE database.

METHODS

The MADRE database is a collection of information on malformed infants with a history of maternal first‐trimester drug exposure. Nine malformation registries participate in the data collection. Cases were defined as infants presenting with a cleft palate or cleft lip, and exposure was defined by the use of corticosteroids during the first trimester of pregnancy.

RESULTS

After 12 years of data collection, the database includes data on 11,150 malformed infants. A slight association is observed between exposure to corticoids for systemic use and the occurrence of cleft lip with or without cleft palate (OR, 2.59; 95% CI, 1.18–5.67).

CONCLUSIONS

If the observed association is real, an interpretation is suggested, based on a likely interaction between corticosteroids and environmental dioxins. It is indeed possible that human fetuses may become sensitive to the teratogenic effect of corticosteroids when they are exposed in utero to environmental pesticides as well. Birth Defects Research (Part A), 2003. © 2003 Wiley‐Liss, Inc.
Aufstieg und Fall der Kolonialwissenschaften im Nationalsozialismus
Authors: Linne Karsten
Published: December 2003

The German colonial plans concerning Africa in the era of National Socialism ascribed a central role the sciences. Scientists of all possible fields launched into activities. Especially subjects which were directly related to the practice of colonial policies, e.g., African languages, ethnology, law, economic sciences, and medicine, were developed. There were colonial ambitions at nearly every German university, but there was one which was designated to become the centre of colonial sciences: the university of Hamburg. It has to be realized that working in this field of studies protected scientists from being drafted by the army for a long time.
Valence Charge Concentrations, Electron Delocalization and β‐Agostic Bonding in d0Metal Alkyl Complexes
Authors: Scherer Wolfgang , Sirsch Peter , Shorokhov Dmitry , Tafipolsky Maxim , McGrady G. Sean , Gullo Emanuel
Published: December 2003

In this paper we describe a range of model d0metal ethyl compounds and related complexes, studied by DFT calculations and high resolution X‐ray diffraction. The concept of ligand‐opposed charge concentrations (LOCCs) for d0metal complexes is extended to include bothcis‐andtrans‐ligand‐induced charge concentrations (LICCs) at the metal, which arise as a natural consequence of covalent metal–ligand bond formation in transition metal alkyl complexes. The interplay betweenlocallyinduced sites of increased Lewis acidity and an ethyl ligand is crucial to the development of a β‐agostic interaction in d0metal alkyl complexes, which is driven by delocalization of the MC bonding electrons. Topological analysis of theoretical and experimental charge densities reveals LICCs at the metal atom, and indicates delocalization of the MC valence electrons over the alkyl fragment, with depletion of the metal‐directed charge concentration (CC) at the α‐carbon atom, and a characteristic ellipticity profile for the CαCβbond. These ellipticity profiles and the magnitude of the CC values at Cαand Cβprovide experimentally observable criteria for assessing quantitatively the extent of delocalization, with excellent agreement between experiment and theory. Finally, a concept is proposed which promises systematic control of the extent of CH activation in agostic complexes.
A Bifunctional Platinum(II) Complex Capable of Intercalation and Hydrogen‐Bonding Interactions with DNA: Binding Studies and Cytotoxicity
Authors: Ma Dik‐Lung , Che Chi‐Ming
Published: December 2003

The interactions of [Pt(CNN)(4‐dpt)]PF6, (1; 4‐dpt=2,4‐diamino‐6‐(4‐pyridyl)‐1,3,5‐triazine, HCNN=6‐phenyl‐2,2′‐bipyridine) with double‐stranded DNA, poly(dA‐dT)2, and poly(dG‐dC)2 were examined by spectroscopic, electrophoretic, and hydrodynamic methods. The spectroscopic data were analyzed with McGhee, van′t Hoff, and Gibbs–Helmholtz equations. In a comparative study, [Pt(CNN)(py)]PF6 (2; py=pyridine) was prepared and the nature of its binding towards DNA was investigated [preliminary results: ChemBioChem 2003, 4, 62–68]. For reactions with calf thymus DNA at 20 °C, the intrinsic binding constants for 1 and 2 are (4.6±0.2)×105 and (2.3±0.3)×104 mol−1 dm3, respectively. Results of DNA‐binding reactions revealed that 1 and 2 preferentially bind to the AT sequence of duplex DNA. Intercalation is the preferred binding mode for 2, whereas both intercalation and minor‐groove binding are observed for 1. Complex 1 is cytotoxic against a number of carcinoma cell lines, including KB‐3‐1, CNE‐3, and HepG2, and remains potent against multidrug‐ or cisplatin‐resistant KB‐V‐1 and CNE1 cell lines, for which the resistance ratios are 1.6 and 1.5, respectively. Importantly, 1 is almost an order of magnitude less toxic to the normal cell line CCD‐19Lu (IC50=176±1.7 μM) and it selectively induced apoptosis leading to cancer cell death with less than 5 % detectable necrosis.
Electron Transfer and Dynamic Infrared‐Band Coalescence: It Looks Like Dynamic NMR Spectroscopy, but a Billion Times Faster
Authors: Londergan Casey H. , Kubiak Clifford P.
Published: December 2003

Broadening and coalescence of infrared bands can occur due to chemical exchange processes occurring on very fast, femtosecond‐to‐picosecond timescales. One such fast process of recent investigation is intramolecular electron transfer in transition‐metal complexes with strong communication between electron‐donor and ‐acceptor sites. The observation of partial coalescence of metal–carbonyl stretching bands in hexanuclear ruthenium mixed‐valence complexes due to electron‐transfer rates on the order of 1011–1012 s−1 is chronicled here. Several important advances have been made with the aid of dynamic infrared‐band coalescence in these complexes, including the observation of dynamic solvent relaxation effects on electron‐transfer rates, the determination of the equilibrium constant between charge‐transfer isomers, and a reconsideration of the theory of electron transfer and delocalization in bridged, near‐delocalized electron‐transfer systems.
Photocurrent Generation in Multilayer Self‐Assembly Films Fabricated from Water‐Soluble Poly(phenylene vinylene)
Authors: Li Hongmei , Li Yuliang , Zhai Jin , Cui Guanglei , Liu Huibiao , Xiao Shengqiang , Liu Yang , Lu Fushen , Jiang Lei , Zhu Daoben
Published: December 2003

A novel, water‐soluble, cationic PPV derivative poly{(2,5‐bis(3‐bromotrimethylammoniopropoxy)‐phenylene‐1,4‐divinylene)‐alt‐1,4‐(2,5‐bis(2‐(2‐hydroxyethoxy)ethoxy))phenylene vinylene} (BH‐PPV) has been synthesized by a Heck coupling reaction. Multilayered assemblies of the BH‐PPV and the sodium salt of hexa(sulfobutyl)fullerenes (C60‐HS) were fabricated successfully by an alternate deposition technique. The multilayer structures were studied by UV/Vis spectroscopy, small angle X‐ray diffraction, and atomic force microscopy. The photoinduced charge transfer property of the self‐assembled multilayer film was also measured by a three‐electrode cell technique. A steady and rapid cathodic 5.5 μA cm−2 photocurrent response was measured as the irradiation of the multilayer film was switched on and off. Importantly, the response of on/off cycling is prompt and reproducible. A possible mechanism for the electron‐transfer process is proposed.
Efficient Synthesis of High Molar Mass, First‐ to Fourth‐Generation Distributed Dendronized Polymers by the Macromonomer Approach
Authors: Zhang Afang , Zhang Bin , Wächtersbach Eva , Schmidt Manfred , Schlüter A. Dieter
Published: December 2003

A homologous series of first‐ to fourth‐generation (G1–G4) dendronized macromonomers, 5, 7, 10, and 12, was synthesized, and their polymerization behavior under radical conditions investigated. These conditions were thermally induced radical polymerization (TRP) and atom‐transfer radical poymerization (ATRP). TRP was applied to all monomers and gave polymers PG1–PG4, whose molar masses range from several millions for PG1 to estimated several hundreds of thousands for PG2 and PG3, and to the oligomeric regime for PG4. ATRP was applied only to the G1 and G2 monomers 5 and 7. Kinetic studies on monomer 5 provide evidence that its polymerization proceeds in a controlled fashion. The highest monomer‐to‐initiator ratios which still gave monomodal molar mass distributions were 300:1 (for 5) and 100:1 (for 7), which correspond to achievable molar mass regime for PG1 and PG2 of approximately Mn=100 000 (DPcalcd(PG1)=200, DPcalcd(PG2)=90). The polydispersities lie in the usual range (PDI=1.1–1.2). The molar masses were determined by GPC in DMF with calibration against absolute molar masses of PG1 determined by light scattering.
X‐ray Structure and Circular Dichroism of Pure Rotamers of Bis[guanosine‐5′‐monophosphate(−1)](N,N,N′,N′‐tetramethylcyclohexyl‐1,2‐diamine)platinum(II) Complexes That HaveR,RandS,SConfigurations at the Asymmetric Diamine
Authors: Benedetti Michele , Tamasi Gabriella , Cini Renzo , Natile Giovanni
Published: December 2003

The use of a sterically hindered diamine ligand (Me4DACH) has allowed for the first time, the isolation and characterization, both in the solid state (X‐ray crystallography) and in solution (circular dichroism), of pure ΔHT rotamers of [Pt(Me4dach)(5′‐GMP)2] (compounds1and2forR,RandS,Sconfigurations of the Me4DACH ligand, respectively). Comparison of the CD spectra obtained for each rotamer, which differ only in the chirality of the Me4DACH ligand (R,RorS,S) or in the chirality of the HT conformation (Δ or Λ), allowed us to conclude that, in the 200–350 nm range, the contributions to the overall CD spectrum that stem from diamine chirality and diamine‐induced chirality of platinum d‐‐d transitions or from sugar chirality are negligible relative to the exciton chiral coupling that occurs for π–π* transitions of thecisguanines. Accurate molecular structures of1⋅10 D2O and2⋅14 D2O (conventional crystallographic agreement indexesR1convergent to 2.07 % and 2.18 %, respectively) revealed that the crystallized rotamers have a ΔHT conformation that is in agreement with all previously reported X‐ray structures of [Pt(diamine)(nucleos(t)ide)2] complexes. This conformation allows the 5′‐phosphate to be located in proximity to the Me4DACH ligand so that (P)O⋅⋅⋅HC(N) hydrogen‐bond interactions exists in both complexes. For both structures, the canting of the guanine planes on the coordination plane is right‐handed (R; canting angle (Φ) of 80.9° and 73.2°, respectively); this indicates that the canting direction is driven by the HT conformation chirality (Δ for both compounds) and not by the chirality of the carrier ligand (different for the two compounds). Density functional theory analysis of the conformational space as a function ofΦindicated a good agreement between the computed and experimental structures. The increase in energy forΦvalues below 65° and 55° (for1and2, respectively) is mainly due to the short intramolecular contacts between C(8)H and thecisNMe groups on the same side of the platinum coordination plane.