bluuebunny/crossref_metadata_2025 huggingface dataset:
A set of female pheromones affects reproduction before, during and after mating inDrosophila
Authors: Marcillac Fabrice , Ferveur Jean-François
Published: October 2004

Sex pheromones are chemical signals used for mate attraction and discrimination in many invertebrate species. These compounds are often complex mixtures with different components having different effects. We tested live Drosophila melanogaster mutant female flies genetically depleted for unsaturated cuticular hydrocarbons, which were then perfumed with these substances to measure their influence on various aspects of reproduction. Female pheromones of the control Cs strain enhanced female attractivity,copulation duration and tended to decrease the number of female progeny of mutant females mated with Cs males, but no dose-dependent effect was found. Cs and variant males showed different response to Cs female pheromone, suggesting a strain-specific coadaptation of female and male characters. The fact that female pheromones induced reciprocal effects on the frequency of the genes contributed by females and males suggests that these substances regulate coevolutionary processes between the sexes.
Hydrodynamics of surface swimming in leopard frogs (Rana pipiens)
Authors: Johansson L. Christoffer , Lauder George V.
Published: October 2004

The kinematics of swimming frogs have been studied extensively in the past and, based on these results, hypotheses regarding the hydrodynamics of frog swimming can be generated. To test these hypotheses we used digital particle image velocimetry (DPIV) to quantify the flow structure of the wake produced by the feet during the propulsion phase of the kick of surface swimming frogs(Rana pipiens). These frogs use two different gaits, asynchronous and synchronous kicking, and the magnitude of the thrust produced by the feet differs between asynchronous (34±5.4 mN foot–1) and synchronous kicking (71±13.3 mN foot–1), as does maximum swimming speed, with higher swimming speed and forces produced during the synchronous kicks. Previous studies have suggested that an interaction between the feet, resulting in a single posteriorly directed fluid jet, as the feet come together at the end of synchronous kicks, may augment force production. Our results show, however, that each foot produces its own distinct vortex ring, in both asynchronous and synchronous kicking of the feet. There is no evidence of a central jet being produced even during powerful synchronous kicks (maximum thrust calculated was 264 mN foot–1). An alternative mechanism of force production could be the lift-based paddling recently suggested for delta-shaped feet of swimming birds. However, the orientation of the vortex rings generated by the feet is almost perpendicular to the swimming direction for both gaits and there is only a slight asynchrony of the shedding of the distal (start) and proximal (stop) vortex rings, which is different from what would be expected by a dominantly lift-based mechanism. Thus, our results do not support lift as a major mechanism contributing to thrust. Instead, our data support the hypothesis that propulsion is based on drag and acceleration reaction forces where the thrust is generated by separated, but attached, vortex rings on the suction side of the feet, resulting in vortices that are shed behind the frogs during both asynchronous and synchronous kicking.
Thermal validation of a misaligned grease-lubricated journal bearing model
Authors: Dick A , Lin C , Wang Y , Wang Q J
Published: October 2004

Bearing temperatures predicted by a misaligned grease-lubricated journal bearing simulation were compared with experimental data. The numerical simulation combines a steady state mixed thermo-elastohydrodynamic lubrication model with a semiempirical soap-thickened grease rheology model. Circumferential temperature profiles were measured using a test fixture and journal test specimens of 5.1 cm diameter and 1.9cm wide over a range of bearing loads (3.8–30kN) and angular misalignments (from −0.08° to 0.05°) at 166r/min rotational speed. The results show that the maximum temperatures in the numerical and experimental profile agree within 5 per cent over the range of loads and misalignments studied.
An investigation into the thermal mixing in journal bearings
Authors: Kosasih P B , Tieu A K
Published: October 2004

Flows in the thermal mixing zone of a journal bearing are investigated using the computational fluid dynamics (CFD) approach. The complexity and inertial effect of the flows inside the supply region of different configurations are considered. It is shown that these flows are highly recirculating but have almost negligible effects on the thermal mixing. The turbulent flow inside the supply region is modelled using the k-ω turbulence model. Most parts of the supply region are filled with recirculation zones and most of the injected cold oil does not immediately enter the oil film. For all configurations considered the extent of the thermal mixing zone is not confined to just above the supply groove. This zone extends some distance beyond the pockets/grooves and in some cases extends for almost the whole bearing length in the axial direction. The length of the supply region and supply pressure governs the extent of the mixing zones. To investigate the effect of various groove dimensions, locations and bearing operating conditions on the bush temperature, the supply region and oil film were considered as separate domains. This allows the difference in length scales to be resolved. The results are presented quantitatively in terms of bush temperatures and maximum temperature. A flow field inside a pocket is compared with available experimental flow visualizations.
Thermal effects on the performance of floating ring bearings for turbochargers
Authors: San Andrés L , Kerth J
Published: October 2004

Physical models and fast computational programs aim to improve the design and performance of turbocharger (TC) rotordynamics. Most commercial automotive TCs incorporate floating ring bearings (FRBs) owing to their low cost and reduced power losses. However, persistent subsynchronous motions afflict this type of rotor/bearing system, albeit reaching limit cycles that enable their continuous operation. FRBs comprise two fluid films in series and are prone to show one or two subsynchronous instabilities over extended speed ranges of operation. A flow model for prediction of FRB forced response is detailed here. The model incorporates a lumped-parameter thermal energy balance for estimation of the lubricant viscosity and thermal growth of the rotor, bearing and floating ring. The FRB model, fully integrated into a non-linear rotordynamics computational program, predicts the floating ring speed, journal and ring eccentricities, power loss and the rotordynamic force coefficients of the inner and outer films as a function of the load applied at a given rotor speed. Knowledge of the actual load conditions, static and dynamic, and the changes in operating clearance and effective lubricant viscosity are most important for accurate estimation of a TC dynamic forced response. Predictions for the exit lubricant temperature, power losses and floating ring speeds agree well with measurements obtained in an automotive turbocharger test rig. The rotordynamic stability characteristics of the test TC are also highlighted.
Thermoelastohydrodynamic lubrication for the connecting rod big-end bearing under dynamic loading
Authors: Souchet D , Hoang L V , Bonneau D
Published: October 2004

This paper discusses an experimental device used to investigate thermoelasto-hydrodynamic behaviour of connecting rod big-end bearing models. Theoretical results for this device are obtained by calculation with a two-dimensional thermoelastohydrodynamic model. A brief description of both theoretical development and experimental device is presented. After the presentation of measurement results, a comparison with theoretical results is discussed.
Measuring the performance of a novel fluid film bearing supporting a rotor on a stationary shaft, by non-contacting means
Authors: Martin J K
Published: October 2004

A description is given of a multi-body dynamics rig for testing a novel rotor fluid film bearing system. The design included a composite rotor supported on a stationary central shaft, with loading applied by non-contacting electromagnets. The shaft included hydrostatic bearing pockets and continuously adjustable hydrodynamic bearing segments. A technique is described for deriving displacement coefficients for both types of bearing. Observations are given on the use of the rig and test techniques, along with some results, and on implications of the results regarding the bearing system.
Media, Education and Anti-Americanism in the Muslim World
Authors: Gentzkow Matthew A , Shapiro Jesse M
Published: October 2004

Recent surveys in the United States and the Muslim world show widespread misinformation about the events of September 11, 2001. Using data from 9 predominantly Muslim countries, we study how such beliefs depend on exposure to news media and levels of education. Standard economic theory would predict that increased access to information should cause beliefs to converge. More recent models of biased belief formation suggest that this result might hinge critically on who is providing the information. Consistent with the latter, we find that overall intensity of media use and level of education have at best a weak correlation with beliefs, while particular information sources have strong and divergent effects. Compared to those with little media exposure or schooling, individuals watching Arab news channels or educated in schools with little Western influence are less likely to agree that the September 11 attacks were carried out by Arab terrorists. Those exposed to media or education from Western sources are more likely to agree. Belief that the attacks were morally justified and general attitudes toward the US are also strongly correlated with source of information. These findings survive controls for demographic characteristics and are robust to identifying media effects using cross-country variation in language.
Economic Policy and Prospects in Iraq
Authors: Foote Christopher , Block William , Crane Keith , Gray Simon
Published: October 2004

This paper describes the Coalition Provisional Authority's attempts to stabilize and reform Iraq's economy along market lines. It argues that while security concerns remain serious, Iraq's economy has not been crippled by violence. However, sustained economic growth will depend on whether Iraq's future leaders pursue the pro-market approaches the Coalition has advocated. If the Iraqi economy is to reach its potential, it will need to go even farther than the Coalition did, implementing reforms the Coalition did not pursue because of security concerns.
Identity construction and British Muslims' political activity: Beyond rational actor theory
Authors: Hopkins Nick , Kahani‐Hopkins Vered
Published: October 2004

Political activity is often addressed in terms of rational actor theory (RAT). We review RAT's psychological assumptions and highlight the neglect of collective identity. In turn, we view the perception of ‘interest’ as contingent upon constructions of identity and explore how different characterizations of collective identity are organized strategically so as to shape people's understandings of their interests and how they should act to realize them. Using examples taken from a study of British Muslims’ political activity we emphasize the contested and strategic dimension to identity construction and analyse how activists addressing the same constituency construe Muslim identity in different ways so as to promote different conceptions of collective interest. Specifically, we explore the contested invocations of Prophetic example in the definition of Muslim identity. The broader thrust behind this work is a critique of the sharp dichotomization of Muslim and non‐Muslim political activity. We maintain that essentially similar processes of identity construction underlie all attempts to organize collective sentiment and political action (including that comprising so‐called ‘conventional’ electoralist politics in the West), and that conceiving of identity as a site of political struggle underscores the inadequacy of Orientalist characterizations of Muslim identity in terms of a singular, transhistorical essence.
The fundamental attribution error: A phenomenological critique
Authors: Langdridge Darren , Butt Trevor
Published: October 2004

The fundamental attribution error (Heider, 1958; Ross, 1977) has been extensively researched and explanations sought within a social cognitive framework. This work is reviewed, and it is noted that there is no unifying theory to account for the extensive catalogue of experimental work. Social cognitive explanations have proposed distinctions between perceptual, inferential and motivational functions within the person to account for the phenomenon. A phenomenological critique of this approach is then advanced. Drawing on the thought of Merleau‐Ponty (1962) it is argued that our understanding of the phenomenon is enhanced by focusing not ‘inside’ people, but on interactions between them. In many ways, this brings us back to the project of Gestalt psychology, Heider's original framework for studying attribution.
Ambivalence and information integration in attitudinal judgment
Authors: Van Harreveld Frenk , Van der Pligt Joop , de Vries Nanne K. , Wenneker Clemens , Verhue Dieter
Published: October 2004

In three studies we investigated the role of bottom‐up information processing in attitudinal judgment. Overall, the results confirm our expectations and show that people are faster in judging attributes underlying their attitude towards the object than in generating or ‘computing’ their overall attitudinal response. As predicted, respondents who selected more attributes as important to their attitude needed more time to integrate these attributes in order to come to an overall attitudinal response. Moreover, ambivalence was also related to decreased response times of the overall attitudinal response. We argue that the main reason for this is that non‐ambivalent attitudes are generally based on evaluatively congruent attributes, while ambivalent attitude‐holders need to integrate evaluatively incongruent attributes into an overall judgment. Implications for research on attitude structure and ambivalence are briefly discussed.
Predictors and predictive effects of ambivalence
Authors: Sparks Paul , Harris Peter R. , Lockwood Nina
Published: October 2004

Recent interest in people's ambivalence about social behaviours and social categories has provoked a number of challenges for the ways in which attitudes are conceptualized. Research into the implications of ambivalence for attitude‐behaviour relationships and for information processing has developed alongside a concern with how best to measure ambivalence and with its implications for the application of social psychological theory. In a study (N = 197) of attendance at a local health club, two novel issues were addressed: firstly, an assessment of the effect of ambivalence on intention‐behaviour relationships (using an objective behaviour measure) revealed the hypothesized moderation effect; secondly, in a move towards identifying some of the factors that may lead to ambivalence, an assessment of potential motivational conflicts based on a consideration of behavioural beliefs and outcome evaluations was introduced. We suggest that this method of assessing ambivalence represents a useful framework on which to build a fuller understanding of the relationship between people's attitudes and the variety of motives that may influence their social behaviour. Pointers for future research are outlined.
The underrepresentation of women in science: Differential commitment or the queen bee syndrome?
Authors: Ellemers Naomi , Van den Heuvel Henriette , de Gilder Dick , Maass Anne , Bonvini Alessandra
Published: October 2004

We examined possible explanations for the underrepresentation of women among university faculty, in two different national contexts. In the Netherlands, a sample of doctoral students (N = 132) revealed no gender differences in work commitment or work satisfaction. Faculty members in the same university (N = 179), however, perceived female students to be less committed to their work and female faculty endorsed these gender‐stereotypical perceptions most strongly. A second study, in Italy, replicated and extended these findings. Again, no gender differences were obtained in the self‐descriptions of male and female doctoral students (N = 80), while especially the female faculty (N = 93) perceived female students as less committed to their work than male students. Additional measures supported an explanation in social identity terms, according to which individual upward mobility (i.e. of female faculty) implies distancing the self from the group stereotype which not only involves perceiving the self as a non‐prototypical group member, but may also elicit stereotypical views of other in‐group members.
Social support and its consequences: ‘Positive’ and ‘deficiency’ values and their implications for support and self‐esteem
Authors: Goodwin Robin , Costa Patricia , Adonu Joseph
Published: October 2004

Recent research on social support has suggested that there may be only a weak correlation between perceived and received (enacted) support, with the former best seen as a stable, personality‐like trait. This study investigates the relationship between individual values, self‐esteem and perceived and received support, with samples taken from four nations (the UK, Portugal, Ghana and Mozambique). Respondents completed Schwartz's Portrait Values Questionnaire (Schwartz, Melech, Lehmann, Burgess, & Harris, 2001) and measures of self‐esteem and perceived and received support. The values explained more than twice the variance for perceived compared with received support, with those scoring high on stimulation, hedonism and benevolence, and low on tradition, conformity and security, reporting greater perceived support. In path analyses, values significantly predicted perceived support and perceived support predicted self‐esteem, but there was no direct relationship between values and self‐esteem. These findings are discussed in the light of current debates on the role of values in the promotion of prosocial behaviour.
External Quality Assessment of Molecular Biology-Based Methods Used in Laboratories of Clinical Chemistry and Human Genetics
Authors: Braun Andreas , Deufel Thomas , Geilenkeuser Wolf-Jochen , Neumaier Michael , Röhle Gerhard , Roscher Adelbert , Wagener Christoph
Published: October 2004

The Reference Institute of Bioanalysis of the German Society of Clinical Chemistry has performed the first external assessment of molecular genetics methods used in medical diagnosis. The following procedures were tested: (I) DNA preparation from whole blood, (II) PCR amplification using “standard” primers, and (III) submarine agarose gel electrophoresis. Out of 50 participants, 45 returned samples for evaluation.
Preoperative Values of Molecular Coagulation Markers Identify Patients at Low Risk for Intraoperative Haemostatic Disorders and Excessive Blood Loss
Authors: Korte Wolfgang , Truttmann Berta , Heim Christoph , Stangl Ulrike , Schmid Luzius , Kreienbühl Georg
Published: October 2004

Conventional laboratory investigations of haemostasis like prothrombin time and activated partial thromboplastin time are not useful in predicting and managing intra-operative bleeding complications. In order to establish a possible “perioperative reference range” for thrombin generation prothrombin fragment F1+2 (F1+2) and fibrin degradation (D-dimer) markers, we measured F1+2 and D-dimer concentrations before surgery (but after induction of anaesthesia), 30 minutes into surgery, 10 minutes after the event expected to induce the maximal activation of the haemostatic systems, 90 minutes after surgery and on postoperative days 1 and 2 in 226 consecutive patients. Samples were collected from arterial lines. Twenty patients developed a clinically defined, intraoperative disorder of haemostasis, 206 did not. Patients with an intraoperative disorder of haemostasis had significantly higher preoperative F1+2 and D-dimer concentrations. Preoperative values for F1+2 and D-dimer concentrations above the 75th percentile of patients without an intraoperative disorder of haemostasis indicated a 2.70 to 2.88 fold risk of developing an intraoperative disorder of haemostasis (odds ratios were 3.04, 3.12 and 3.29 for D-dimer, ELISA, F1+2, and D-dimer latex tests, respectively with 95% confidence intervals from 1.20 to 8.46) with negative predictive values of 94%, but positive predictive values of only 16% to 26%. These data suggest that preoperative determination of molecular markers might be helpful in identifying a group of patients at high risk for intraoperative disorder of haemostasis by exclusion of low risk patients. Validation of such an approach requires a prospective trial.
Rifampicin Causes False-Positive Immunoassay Results for Urine Opiates
Authors: de Paula Marta , Saiz Luis C. , González-Revaldería Joaquín , Pascual Tomás , Alberola Carmen , Miravalles Elena
Published: October 2004

The treatment of tuberculosis usually includes the antibiotic rifampicin, especially in patients with concomitant human immunodeficiency virus infection. Some of these patients are in withdrawal therapy for drug abuse. When opiate screening is carried out in patients receiving rifampicin, false positive results are detected with the kinetic interaction of microparticles in solution method. We evaluated this interference in a Cobas-Integra analyzer and found a 12% cross-reactivity of rifampicin for antibiotic concentrations ranging from 0.19 to 6.08 μmol/l (156 to 5000 μg/l). This effect is not explained by the colour of the rifampicin solutions. Calculations assuming first order kinetics of elimination show that more than 18 hours after a single oral dose of 600 mg of rifampicin, a false positive result for opiates could be obtained. This indicates that the risk of a false positive result must always be considered when urine samples from these patients are analyzed.
Mutation Analysis of Exon 3 of the LDL Receptor Gene in Patients with Severe Hypercholesterolemia
Authors: Geisel Jürgen , Gielen Jörg , Oette Kurt , Herrmann Wolfgang , Wielckens Klaus
Published: October 2004

Single-strand conformation polymorphism analysis was used to screen for mutations in exon 3 of the low density lipoprotein receptor gene in a group of 218 unrelated patients with severe hypercholesterolemia (low density lipoprotein cholesterol > 6.7 mmol/l) living in the Cologne area of Germany. Including the complementary primers the fragment studied had a length of 176 bp. An abnormal single-strand conformation polymorphism pattern was observed in eight patients, four of whom had an identical abnormal fragment pattern indicating that five different mutations were present. By direct DNA sequencing, the underlying mutations could be confirmed (Cys54→Tyr, Trp66→Gly, Glu80→Lys, 2 bp insertion (AT between codon 44 and 45, 9 bp deletion (codons 65 to 67)). The analysis of the pathogenicity indicates that all mutations were causative for the low density lipoprotein cholesterol elevation. The Trp66→Gly and Glu80→Lys mutations were previously described in a French-Canadian population and in an English population, respectively. The 2 bp insertion was detected in four unrelated patients and is one of the most frequent mutations detected up to now in the German population.
Long-Term Variability of Serum Lipoprotein(a) Concentrations in Healthy Fertile Women
Authors: Garnotel Roselyne , Monier Frédérique , Lefèvre Fabrice , Gillery Philippe
Published: October 2004

Lipoprotein(a) is a unique lipoprotein with atherothrombogenic properties. Although its blood concentration is mainly genetically determined, various factors exist which may cause variability. These may influence the clinical use of the results. We studied lipoprotein(a) biological variation by a rate nephelometric assay over a period of two years in a population of healthy fertile women. The study was performed in 12 volunteers, healthy subjects with various lipoprotein( a) concentrations, by monthly determinations during one year and a single determination one year later, together with measurements of total, high density lipoprotein and high density lipoprotein2 cholesterol, triglycerides and apolipoproteins A1 and B. The intra-individual variability of lipoprotein(a) ranged between 4 to 20%, with three subjects showing a coefficient of biological variation higher than 15 %. In absolute terms, the difference between two determinations could represent 0.44 g/l or 50 % of the mean value. This study suggests that physiological lipoprotein( a) variations should be taken into account for clinical purposes, especially in patients in need of thorough risk evaluation.
Standardization of Steroid Immunoassays – In Theory an Easy Task
Authors: Thienpont Linda M.
Published: October 2004

I deal with the process of standardization of steroid
immunoassays on the basis of metrological traceability (SI units). First, I
discuss the role theoretically attributed to the calibration of the measurement
procedure. Since immunoassays show matrix sensitivity, I associate traceability
of calibration with traceability of results pertaining to individual patient
samples. From this, I stress that optimization of the immunoassays in terms of
specificity and insensitivity to different kinds of interference is necessary
before standardization, and that split-sample measurements should be included in
the standardization process. Last but not least, I give an overview of the
current status of standardization of steroid immunoassays.
Thermodynamic Parameters in Immunoassay
Authors: Regenmortel Marc H. V. Van
Published: October 2004

Although affinity and kinetic measurements on their own
provide useful information regarding the suitability of antibodies for various
immunoassays, a thermodynamic analysis provices additional information that
throws light on the molecular forces at work in the antigen-antibody
interaction. It may then be possible to adjust assay conditions in order to
favour either the association or dissociation of antigen-antibody complexes. A
tenfold increase in binding affinity (K) corresponds to a free energy change of
only 1.4 kcal/mol (5.8 kJ/mol) at 25 °C. This means that K values of
105 M−1 and 1010 M−1 correspond to a
free energy change (∆G) of 7.0 and 14.0 kcal/mol respectively. The entire range
of affinity constants normally encountered in antigen-antibody interactions,
therefore differs by no more than about 7 kcal/mol of free energy change, which
is equivalent to only a few hydrogen bonds. In comparison, a single
electrostatic interaction corresponds to about 4 kcal/mol of free energy change.
A full description of the binding interaction requires an understanding of the
change in hydration states of the reactants when the complex forms, and an
assessment of the entropic andenthalpic effects of these changes. Contrary to
earlier assumptions, it is now clear that antigen-antibody interactions are
often accompanied by a large favourable enthalpy which more than compensates the
unfavourable entropy.
Antigenic Definition of Cardiac Troponin I
Authors: Larue Catherine , Ferrieres Gaëlle , Laprade Michel , Calzolari Charles , Granier Claude
Published: October 2004

The presence of cardiac troponin I in the serum is now
considered as one of the most specific biochemical markers of acute myocardial
infarction. To improve the knowledge of the antigenic properties of cardiac
Troponin I, a set of monoclonal antibodies and polyclonal antibodies against
human cardiac troponin I has been tested with overlapping peptides covering the
cardiac troponin I sequence. The results indicate that N-terminal and C-terminal
cardiac troponin I regions were most often recognized by poly- and monoclonal
antibodies. These observations are valuable for choosing the best combination of
monoclonal antibodies to set up new immunoassays to detect serum cardiac
troponin I earlier after myocardial damage, to understand better which forms are
released, and finally to propose appropriate cardiac troponin I standards.
Rapid Electrophoretic Separation of Pre-ß-Migrating High Density Lipoproteins Using Automated PhastSystem(tm): Application to Analysis of Lecitihin: Cholesterol Acyltransferase-Deficient Plasma
Authors: Saïdi Youssef , Sich Didier , Federspiel Marie-Christine , Auer Claude , Egloff Monique , Castro Gracielo R. , Beucler Isabel
Published: October 2004

To identify pre-β-high density lipoproteins, a rapid
two-dimensional separation by electrophoresis (1 hour 30 minutes) was performed
on an automated Phast System™. This procedure used commercially available
polyacrylamide gradient gels (4–15 %) and allows sensitive and reproducible
results. Pre-β-1- and pre-β-2-high density lipoproteins were clearly identified
by this method. In addition, our procedure was successfully applied to diagnosis
of a patient with familial lecithin: cholesterol acyltransferase deficiency,
characterized by the absence of α-high density lipoproteins.
Cytokines and Soluble Adhesion Molecules in Laboratory Diagnostics. Report from a Meeting Held at the German Cancer Research Center in Heidelberg on 25 November 1997
Authors: Bertsch Thomas , Richter Axel
Published: October 2004

Cytokines and soluble adhesion molecules play an increasing role in laboratory medicine especially due to the increasing knowledge of the function of the immune system and the availability of cytokine assays on analyzers working in the "random-access" mode. This meeting report gives an insight of different applications for the measurements of these immunomediators. Examples from surgery, pediatrics, transplantation medicine and immunopharmacology show that these parameters could provide early and useful information for diagnosis, prognosis, therapeutic decision making and drug actions.
Will humans swim faster or slower in syrup?
Authors: Gettelfinger Brian , Cussler E. L.
Published: October 2004

Foreword

The scientific and engineering principles that underlie chemical engineering can also be used to understand a wide variety of other phenomena, including in areas not thought of as being central to our profession. As such applications might be of interest to our readers, we will consider brief submissions for publication in this category as R&D notes. These submissions will undergo review, and novelty will be an important factor in reaching an editorial decision.

The first such article, “Will Humans Swim Faster or Slower in Syrup?” by Brian Gettelfinger and associate editor Ed Cussler, appears in this issue. Stanley I. Sandler Editor
Within‐group social relationships among females and adult males in wild western lowland gorillas (Gorilla gorilla gorilla)
Authors: Stokes Emma J.
Published: October 2004

Within‐group female relationships, and relationships between females and adult males have not been described for wild western lowland gorillas. New data are presented here from Mbeli Bai in the Nouabalé‐Ndoki National Park, Republic of Congo. Nine groups were observed over a continuous 2‐year period, and affiliative and agonistic interactions, as well as time spent by females and adult males in proximity to each other were recorded. Affiliative behavior was extremely rare in the bai, and measures of proximity between individuals were inconclusive because of the small sample sizes. Rates of agonistic interaction among females were highly variable between groups. The majority of agonistic interactions were undecided, and the supplant rate was low. Evidence for an agonistic dominance hierarchy is weak. The data do not support hypotheses that increased frugivory in western lowland gorillas raises levels of within‐group contest competition; however, the need for intersite comparisons is stressed. In contrast, rates of agonistic behavior between females and silverback males were higher and more consistent between groups. Agonistic relationships between males and females conformed with patterns seen in mountain gorillas, where male protection from intraspecific aggression is important. The benefit females gain by forming long‐term cooperative alliances appears to be small, and is likely outweighed by reproductive advantages associated with male protection. Am. J. Primatol. 64:233–246, 2004. © 2004 Wiley‐Liss, Inc.
Rheological study of poly(ethylene glycol)/poly(N‐isopropylacrylamide‐co‐2‐acrylamido‐2‐methylpropanesulphonic acid) semiinterpenetrating network formation
Authors: Zhang Chi , Easteal Allan J.
Published: October 2004

The formation of a series of semiinterpenetrating network (SIPN) hydrogels made by free‐radical copolymerization of N‐isopropylacrylamide (NIPA) and 2‐acrylamido‐2‐methylpropanesulphonic acid (AMPS) with varying comonomer mole ratios, crosslinked with N,N′‐methylene‐bisacrylamide (MBAA) in the presence of poly(ethylene glycol) (PEG) with average molecular weight 6,000 g mol−1 was studied via determination of complex viscosity, η*, using plate–plate rheometry. The isothermal time dependence of η* at various temperatures or the variation of η* with temperature of pregel solutions was utilized to detect the onset of gelation. The SIPN systems were compared with the corresponding gels made under the same conditions in the absence of PEG. The copolymer mainchain composition has a major effect on the time or temperature for onset of gelation and in particular gelation appears to be inhibited to some extent by MBAA when the AMPS/NIPA mole ratio in the pregel solution exceeds 0.5. The presence or absence of PEG in pregel solutions has a lesser effect on gelation. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2083–2087, 2004
Imparting affinity sites for adenosine triphosphate on the surface of polyurethane through molecular imprinting
Authors: Sreenivasan K.
Published: October 2004

A simple methodology for imparting affinity sites for adenosine triphosphate (ATP) on the surface of polyurethane (PU) film is discussed. It is widely known that, through oxidation, a thin layer conjugated polymer can be coated onto many polymeric substrates. This possibility is explored in this report. 3‐Amino phenyl boronic acid was polymerized in the presence of ATP as template using ammonium per sulfate. A thin layer of polyamino phenyl boronic acid was coated onto the surface of PU film immersed in the solution during the reaction. The coated layer showed remarkably high affinity toward ATP and equilibrium adsorption was attained rapidly in contrast to free standing molecularly imprinted polymers in which equilibrium adsorption is normally attained after several hours. The imprinted layer also showed a high degree of selectivity toward ATP compared to adenosine diphosphate (ADP). The approach is simple and affinity sites for any water soluble molecules can virtually be created on the surface of polymers of interest. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2088–2090, 2004
Polyimides containing 4,4′‐bipyridinium units
Authors: Gaina C. , Gaina V. , Airinei A. , Avram E.
Published: October 2004

New polyimides containing 4,4′‐bipyridinium units were synthesized by the reaction of bis(dichloromaleimide)arylene derivatives with 4,4′‐bipyridine in meta‐cresol. IR and 1H‐NMR spectroscopy and elemental analysis as well confirmed their structures. The polymers were characterized by viscometric measurements, softening points, and thermogravimetric data. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2091–2100, 2004
Pervaporation separation of water–acetic acid mixtures through NaY zeolite‐incorporated sodium alginate membranes
Authors: Kittur A. A. , Tambe S. M. , Kulkarni S. S. , Kariduraganavar M. Y.
Published: October 2004

The pervaporation (PV) separation and swelling behavior of water–acetic acid mixtures were investigated at 30, 40, and 50°C using pure sodium alginate and its zeolite‐incorporated membranes. The effects of zeolite loading and feed composition on the pervaporation performance of the membranes were analyzed. Both the permeation flux and selectivity increased simultaneously with increasing zeolite content in the polymer matrix. This was discussed on the basis of a significant enhancement of hydrophilicity, selective adsorption, and molecular sieving action, including a reduction of pore size of the membrane matrix. The membrane containing 30 mass % of zeolite showed the highest separation selectivity of 42.29 with a flux of 3.80 × 10−2 kg m−2 h−1 at 30°C for 5 mass % of water in the feed. From the temperature dependency of diffusion and permeation data, the Arrhenius activation parameters were estimated. The Ep and ED values ranged between 72.28 and 78.16, and 70.95 and 77.38 kJ/mol, respectively. The almost equal magnitude obtained in Ep and ED values signified that both permeation and diffusion contribute equally to the PV process. All the membranes exhibited positive ΔHs values, suggesting that the heat of sorption is dominated by Henry's mode of sorption. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2101–2109, 2004
Rheological and mechanical properties of compatibilized polystyrene/ethylene vinyl acetate blends
Authors: Tang L. W. , Tam K. C. , Yue C. Y. , Hu X. , Lam Y. C. , Li L.
Published: October 2004

In this study, a blend of polystyrene (PS)/ethylene vinyl acetate (EVA) (PS/EVA, 90 : 10 wt %) was compatibilized with three different block copolymers, in which their end blocks were compatible with either styrene or EVA. The compatibilized blends with different compositions were prepared using a twin‐screw extruder and injection molded into the required test specimens. Mechanical properties of the blends, such as tensile properties and Charpy impact strength, morphology of tensile fractured surfaces, rheological properties, and thermal properties, were investigated. The results show that the interaction between the dispersed and continuous phase can be improved by the addition of a compatibilizer. Appreciable improvement in the impact strength of the blend with 15 wt % of compatibilizer C (polystyrene‐block‐polybutadiene) was observed. Its mechanical properties are comparable to those of the commercial high‐impact polystyrene, STYRON 470. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2071–2082, 2004
Effect of molecular chain structure of the cured epoxy resin containing hyperbranched (3‐hydroxyphenyl) phosphate on expansion and flame retardance
Authors: Deng Jing , Zhu Shengwu , Shi Wenfang
Published: October 2004

Melamine is widely used as a blowing agent in intumescent flame‐retardant systems. However, when it was blended into the epoxy resin cured with hyperbranched (3‐hydroxyphenyl) phosphate (HHPP), neither greater expansion nor improved limiting oxygen index (LOI) was obtained during combustion compared with that without melamine addition. When a portion of HHPP was replaced by polyethylene glycol (PEG), both the expansion degree and the LOI increased, along with the content of PEG, even if the same amount of melamine was blended. This phenomenon shows that the molecular chain structure of the cured epoxy resin based on HHPP has a substantial effect on the flame retardance. Only when the degraded products are sufficiently viscous, at the decomposition temperature of the blowing agent, can the material be bubbled to form an expanding charred crust. The morphologic structure of the crust of the epoxy resin cured with HHPP shows that there were many holes on the surface because the degraded products were too rigid to be bubbled, from which the gases formed by melamine evolved. With increasing PEG content, the degraded products became increasingly viscous and bulged more easily with the gases. No holes appeared on the charred crust of the sample cured with the mixture of HHPP and PEG at a ratio of 3:1. In this case, most of the gases were entrapped and caused the material to expand, resulting in the increases of expansion degree and LOI. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2065–2070, 2004
Effect of vibration on crystal morphology and structure of isotactic polypropylene in nonisothermal crystallization
Authors: Zheng Qiang , Shangguan Yonggang , Tong Lifang , Peng Mao
Published: October 2004

An experimental study on crystal structure and morphology of isotactic polypropylene (iPP) subjected to vibration was carried out on a laboratory apparatus. Crystallite size, crystal structure, and crystallinity of iPP under vibration or nonvibration were investigated through differential scanning calorimeter (DSC), wide angle X‐ray diffraction (WAXD), and polarized optical microscopy (POM). The results reveal that at high cooling rate, the crystallinity of samples under vibration decreases, and at low cooling rate it remains constant because of chain relaxation. On the other hand, the sizes of the iPP spherulites under vibration decrease as compared with those without vibration. Taking the relaxation of the iPP chain into consideration, we believe that the influence of vibration conditions on the main α‐form of the iPP crystal is rather complex. An obvious increase of β‐form content in the crystal phase results from the imposition of vibration. The results indicate that the content of β‐iPP is dependent on vibration amplitude and time. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2187–2195, 2004
Isothermal crystallization kinetics and melting behavior of nylon/saponite and nylon/montmorillonite nanocomposites
Authors: Wu Tzong‐Ming , Lien Yi‐Hsin , Hsu Sung‐Fu
Published: October 2004

DSC thermal analysis and X‐ray diffraction have been used to investigate the isothermal crystallization behavior and crystalline structure of nylon 6/clay nanocomposites. Nylon 6/clay has prepared by the intercalation of ε‐caprolactam and then exfoliating the layered silicates by subsequent polymerization. The DSC isothermal results reveal that introducing saponite into the nylon structure causes strongly heterogeneous nucleation induced change of the crystal growth process from a two‐dimensional crystal growth to a three dimensional spherulitic growth. But the crystal growth mechanism of nylon/montmorillonite nanocomposites is a mixed two‐dimensional and three‐dimensional spherulitic growth. The activation energy drastically decreases with the presence of 2.5 wt % clay in nylon/clay nanocomposites and then slightly increases with increasing clay content. The result indicates that the addition of clay into nylon induces the heterogeneous nucleation (a lower ΔE) at lower clay content and then reduces the transportation ability of polymer chains during crystallization processes at higher clay content (a higher ΔE). The correlation among crystallization kinetics, melting behavior, and crystalline structure of nylon/clay nanocomposites is also discussed. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2196–2204, 2004
Preparation of superparamagnetic immunomicrospheres and application for antibody purification
Authors: Liu Xianqiao , Guan Yueping , Yang Yu , Ma Zhiya , Wu Xiaobing , Liu Huizhou
Published: October 2004

A novel and effective protocol for the preparation of superparamagnetic immunomicrospheres has been developed. First, micro‐size magnetic poly (methacrylate‐divinylbenzene) (PMA‐DVB) spheres were prepared by a modified suspension polymerization method. The oleic acid coated magnetite (Fe3O4) nanoparticles made by coprecipitation were mixed with monomers of MA, DVB, and initiator benzoyl peroxide (BPO) to form oil in water emulsion droplets with the presence of poly (vinyl alcohol) (PVA‐1788) as a stabilizer. The polymerization reaction was carried out in a 2‐L beaker equipped with four vertical stainless steel baffleplates by increasing the temperature of the mixture at a controlled rate. The resulting magnetic microspheres are micro‐sized (less than 8μm in diameter) and 80 percent of them are in the size ranging from 1 to 5 μm. Then, they were highly functionalized via ammonolysis reaction with ethylenediamine, and the surface amino‐modified magnetic microspheres were obtained. The morphology and properties of these magnetic microspheres were examined by SEM, TEM, VSM, and FT‐IR. Affinity ligand protein A (ProtA) was covalently immobilized to the amino‐modified magnetic microspheres by the glutaraldehyde method. These ProtA‐immobilized magnetic immunomicrospheres were effective for affinity bioseparation processes, as was demonstrated by the efficient immunoaffinity purification of antibodies IgG2a (22mg per gram of microspheres) from mouse ascites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2205–2211, 2004
Polymerized high internal phase emulsions containing a porogen: Specific surface area and sorption
Authors: Sergienko Anatoly Y. , Tai Huwen , Narkis Moshe , Silverstein Michael S.
Published: October 2004

Highly porous, open‐cell polymers [poly(HIPE)] were prepared by polymerizing the monomers in the continuous phase (∼ 10%) of high internal phase emulsions (HIPE). This paper discusses using poly(HIPE) to remove bromoform from an aqueous solution through sorption, a combination of adsorption and absorption. The crosslinked polystyrene (xPS) and crosslinked poly(ethylhexyl acrylate) (xPEHA) had cell diameters from 1.5 to 15 μm, intercellular pore diameters from 0.3 to 1.5 μm, and densities of about 0.10 g/cc. The specific surface area of the glassy xPS increased from 7.9 to 28.8 m2/g on extraction in methanol, most likely due to crazing. The use of a toluene porogen in the xPS (xPS‐T) reduced the density to 0.05 g/cc and yielded a rough surface with nanoscale porosity and a specific surface area of 132 m2/g. xPS and xPEHA, with very different molecular structures but with similar specific surface areas, exhibited similar sorption behavior. Extraction produced increases in the xPS and xPS‐T sorption plateaus and sorption capacities. For larger specific surface areas, the sorption at low concentrations was relatively independent of concentration, indicating a case of adsorption with the sites occupied. For all the other cases, absorption seems to dominate and sorption is more strongly dependent upon concentration. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2233–2239, 2004
Ethylene–propylene–rubber (EPR)/polydimethylsiloxane (PDMS) binary polymer blends: Morphology and viscoelastic properties
Authors: Carlberg M. , Colombini D. , Maurer F. H. J.
Published: October 2004

Melt mixed blends of ethylene–propylene–rubber (EPR) and polydimethylsiloxane (PDMS) were studied with regard to the composition dependence of the dynamic viscoelastic properties in relation to their morphology. Differential scanning calorimetry, scanning electron microscopy, and dynamic mechanical analysis (DMA) were used together with theoretical predictions to characterize the blends. The investigation of the viscoelastic properties showed significant improvement of the mechanical properties of the blends following the increase of the EPR content. The association of DMA results and theoretical predictions indicated that the studied blends consisted of dispersed PDMS in a matrix of EPR over the whole composition range. The microscopy study of the blends also supports these morphological conclusions. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2240–2249, 2004
Conversion of polyester into heat‐resistant polyamide by reacting with aromatic diamine compound II. Semibatch reaction by nitrogen gas sweeping process
Authors: Kim Yangsoo , Choi Young‐Jin
Published: October 2004

The conversion of poly(ethylene terephthalate) (PET) into heat‐resistant polyamide was carried out in the solid state polycondensation by applying a nitrogen gas sweeping process. The reaction product obtained by the catalyzed and uncatalyzed batch reaction with the specified reaction condition was used as the starting material in the semibatch reaction process. Nitrogen gas was introduced into the reactor to remove a volatile reaction byproduct from the reaction mixture. Effect of the semibatch reaction variables such as temperature, time, and nitrogen gas sweeping rate on the extent of reaction and the heat‐resistant property of polyamide obtained was investigated. A comparison of the extent of reaction in the semibatch reaction process was made between the catalyzed starting material and the uncatalyzed one. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2223–2232, 2004