bluuebunny/crossref_metadata_2025 huggingface dataset:
Model based project centered team learning
Authors: Amzad Imtiaz , Ortiz Arturo Jose
Published: July 2006

In this paper, we describe a model to support the non-technical aspects of team development. This model has been derived from studies of student team work at Pace University and through a number of student surveys. The model provides a framework to assess team practices and subsequently guide team members through material specific to their learning needs.
Introducing python into the first year curriculum at wits
Authors: Holt Alexander , Rauchas Sarah , Sanders Ian
Published: July 2006

Since 1999 the School of Computer Science (CS) at the University of Witwatersrand (Wits) has been using Scheme as the first programming language our students encounter [2]. We chose Scheme because it is a language unfamiliar to most of the first year students, so that the students with imperative programming experience from school would not have an advantage over those who did not. Also, it has a simple syntax which we felt that students without prior programming experience could easily learn. Finally, the functional paradigm allows a more direct mapping of mathematical concepts to programs, which fits with the mathematical emphasis in our curriculum.
Teaching web services using .NET platform
Authors: Assunção Luís , Osório António Luís
Published: July 2006

Teaching Web Services concepts, standards and technologies is a difficult and a long process if we have not chosen the right tools [1]. Nowadays there are several open source tools and platforms, but some of them are not suitable to teach.This poster describes our experience by using Microsoft .NET platform and Visual Studio .NET with Web Services Enhancements (WSE) to teach basic Web Services concepts and related technologies.
Exploring teacher methodology
Authors: Godejord Per Arne
Published: July 2006

This paper describes a unique, educational project that was implemented in the undergraduate study of Computer Science in 2002. Nesna University College has been using the example of sexual abuse of children in case study teaching in Social Informatics. The Computer Science education at Nesna University College is the only Computer Science education in the world which has sexual abuse of children as the main topic on the Computer Science curriculum. This exceptional cooperation between Nesna University College, Save the Children Norway and the Norwegian police makes the project not only unique, but might also be a major factor in both the willingness of students to learn Social Informatics and their skills in the various topics of Social Informatics.
Greenfoot demonstration
Authors: Henriksen Poul
Published: July 2006

While the introduction of object-oriented programming slowly moves down the age groups - starting from advanced university courses, to introductory courses, and now into high schools - many attempts are being made to make object-oriented programming introduction less abstract and theoretical. Visualisation and interaction techniques are being applied in an attempt to give students engaging and concrete experiences with objects.Recently, the Greenfoot [1],[2] environment has been proposed as another step in this development. Greenfoot is a programming environment and framework for introductory programming education. This demonstration will show what Greenfoot is and how it can be used.
GoJava
Authors: Wise Jon
Published: July 2006

This is an abstract supporting a demonstration of software developed to help the teaching of Java programming to students without prior experience of computer programming.
WeBWorK for programming fundamentals
Authors: Baldwin Jacqueline , Crupi Eileen , Estrellado Tabitha
Published: July 2006

WeBWorK is a web-based assessment tool developed at the University of Rochester to generate, deliver, and automatically grade homework problems and distribute their solutions. Sharing the market with similar systems, WeBWorK differs in that it is free and open-source. It provides an advanced processing of mathematical formulae and a high-level of problem randomization. Although it was used initially used in mathematics and physics, we are working on extending and adapting WeBWorK for programming fundamentals and computer science.
Application of finite state automata to the bakery algorithm in critical section modeling
Authors: Bozic Vladan
Published: July 2006

The Bakery Algorithm (BA), developed by Dr. Leslie Lamport [1], is utilized as a method to a critical section (CS) problem modeling. A common solution to a CS problem in Operating Systems (OS) must satisfy the three requirements: (1) mutual exclusion; (2) progress; and (3) bounded waiting. The property of BA that is most important for this investigation is that it solves the mutual exclusion problem, while satisfying the requirements of CS. The system consisting of two processes is investigated. The proposed computational model may be extended to any number of processes. By offering clarity to the CS problem, this model may be used in OS design due to its simplistic computational structure, as well as it could be applied to teaching Operating Systems.
A web-based information centre to provide help, guidance and support for students
Authors: Ekman Josephine
Published: July 2006

Researchers have explored ways of improving the educational system through interactive online learning, with the added bonus of saving time, space and cost. More and more universities are implementing a variety of systems from personal websites, video streaming of lectures, to online tutorials. As technology advances so does the desire to expand the online learning experience through a more interactive, centralized and personal learning environment targeted at providing support and guidance to students.
PEPM 2006 paper abstracts
Authors: Bailey Mark W. , Hatcliff John , Tip Frank
Published: July 2006

The ACM SIGPLAN Workshop on Partial Evaluation and Program Manipulation (PEPM 2006) was held on January 9th and 10th in Charleston, South Carolina and this article contains abstracts for the 19 papers presented at the workship. The PEPM workshops focus on techniques, supporting theory, tools, and applications of the analysis and manipulation of programs. The full proceedings for this workshop are available from ACM.
Adrenal Function Improves in Asthmatic Children on Inhaled Steroids: A Longitudinal Study
Authors: Priftis Kostas N. , Papadimitriou Anastasios , Anthracopoulos Michael B. , Gatsopoulou Evi , Fretzayas Andrew , Nicolaidou Polyxeni , Chrousos George P.
Published: July 2006

Background/Aims: Asthmatic children on long-term treatment with inhaled corticosteroids (ICS) may exhibit mild adrenal suppression. We aimed to test the hypothesis that baseline adrenal function of some asthmatic children might be lower than that of others and that this difference might be accentuated by ICS therapy. Methods: A low-dose Synacthen test was performed in 41 prepubertal asthmatic children placed on long-term inhaled budesonide (400 µg/day) prior to the onset of ICS treatment, 6 and 12 months later. Five children withdrew before the 6- and another 2 before the 12-month follow-up. Results: Low adrenal function was demonstrated in 4 children (9.8%) upon recruitment and in another 8 at the 6-month evaluation (22.2%). Adrenal function normalized in the aforementioned 4 children at the 6-month evaluation, while 6 (17.6%) exhibited suppressed adrenal function at the 12-month evaluation. Three of these patients had also exhibited adrenal suppression at the 6-month visit. A significant improvement in peak cortisol values from baseline to the 6- and 12-month evaluation (95% confidence intervals: –283.9 to –69.0 and –239.8 to –50.8, respectively) was evident when children with suppressed adrenal response at the second or third evaluation were excluded. Conclusions: In many asthmatic children, adrenal response improves on long-term ICS. The expected adrenal suppression of certain patients on maintenance ICS appears to constitute a separate phenomenon.
Remodeling of the Cone Photoreceptor Mosaic during Metamorphosis of Flounder (Pseudopleuronectes americanus)
Authors: Hoke Kim L. , Evans Barbara I. , Fernald Russell D.
Published: July 2006

The retinal cone mosaic of the winter flounder, Pseudopleuronectes americanus, is extensively remodeled during metamorphosis when its visual system shifts from monochromatic to trichromatic. Here we describe the reorganization and re-specification of existing cone subtypes in which larval cones alter their spatial arrangement, morphology, and opsin expression to determine whether mechanisms controlling cell birth, mosaic position, and opsin selection are coordinated or independent. We labeled dividing cells with tritiated (3H) thymidine prior to mosaic remodeling to determine whether existing cone photoreceptors change phenotype. We also used in situ hybridization to identify mosaic type and opsin expression in transitional retinas to understand the sequence of transformation. Our data indicate that in the winter flounder retina the choice of new opsin species and the cellular rearrangement of the mosaic proceed independently. The production of the precise cone mosaic arrangement is not due to a stereotyped series of sequential cellular inductions, but rather might be the product of a set of distinct, flexible processes that rely on plasticity in cell phenotype.
Prolonged Ovalbumin Exposure Attenuates Airway Hyperresponsiveness and T Cell Function in Mice
Authors: Swirski Filip K. , D’Sa Abigail , Kianpour Sussan , Inman Mark D. , Stämpfli Martin R.
Published: July 2006

Background: Continuous exposure of sensitized mice to an innocuous antigen, such as OVA, does not lead to chronic airway eosinophilia, but induces antigen unresponsiveness and resolution of the inflammatory response. In this study we explored mechanisms underlying attenuation of the airway inflammatory response, assessed whether the phenomenon is strain-specific, and determined its consequences to airway physiology. Methods: Mice were sensitized and exposed to OVA for two and four weeks. Analysis involved BAL, flow cytometry, adoptive transfer of OVA specific CD4 T cells, ex vivo cytokine expression and response to methacholine challenge. Results: Chronic exposure to antigen resulted in decreased eosinophilia in 5 different mouse strains. Likewise, numbers of lung CD4 T cells expressing activation and Th2 markers sharply declined following continuous OVA exposure. Transfer studies using OVA TcR transgenic cells revealed that the contraction of lung T cells included antigen-specific cells. Systemically, we observed a loss of Th2 memory effector function. Finally, we observed significantly attenuated airway hyper-responsiveness (AHR) in chronically exposed animals. Conclusions: Attenuation of airway eosinophilia in response to chronic OVA exposure is independent of genetic background. Airway eosinophilia, but not systemic responses, correlates with and is predictive for airway hyperresponsiveness. Our study contributes to the understanding of immune regulatory processes controlling antigen-driven airway inflammatory responses.
Agrippa and the Mourning Rites for Drusilla in Alexandria
Authors: Kerkeslager Allen
Published: July 2006

Philo's descriptions of the outburst of violence in Alexandria in 38 suggest that he was trying to distract attention away from some crime against Rome committed by the local Judeans. Careful analysis of the chronology suggests that this crime was a dramatic violation of the Alexandrian funerary celebrations for Drusilla, the sister of the Roman emperor Gaius. The edict of Flaccus and subsequent violence against the Judeans was a punitive response to this crime. The entire sequence of events was fully in harmony with normal Roman legal and administrative policies.
Children and Childhood in Light of the Demographics of the Jewish Family in Late Antiquity
Authors: Tropper Amram
Published: July 2006

The demography of the Jewish family is indispensable for the study of the nature of Jewish childhood in late antiquity. Demography in this context refers to the probable mortality rate, fertility rate and average age of first marriage for the Jews of our period. Together these demographic factors create a model of the duration and rhythm of the life-course; a model of the skeletal structure of the ancient Jewish family. We explore below the nature of Jewish childhood in late antiquity in light of the portrait of the family that emerges from a study of ancient family demographics.
United States' Policy towards Iran after the Islamic Revolution
Authors: Yazdani Enayatollah , Hussain Rizwan
Published: July 2006

The United States has pursued an antagonistic policy towards the Islamic Republic of Iran ever since the fall of the pro-US monarchy. Even though subsequent US administrations since 1979 have been trying to restore earlier influence in that country, the disintegration of the Soviet Union has reinforced the US resolve to regain political leverage in Iran. The realization of this objective could remove a major impediment to the growing US hegemony in the region. Thus, Iran forms part of the Bush administration's so-called ‘axis of evil’. The Iranian Islamic government's autonomous foreign and domestic policies pose a challenge to the US-led Western bloc's preponderant political, military and economic influence in the Persian Gulf and South-west Asia. The ongoing pressure on Tehran to abandon its nuclear programme is an integral component of a multifaceted strategy that seeks to isolate Iran both at the regional and international levels. The US-led occupations of Iraq and Afghanistan in the aftermath of the 11 September events have facilitated the encirclement of Iran with US military power. Further, the absence of a global counter-weight to check US interventionism in the region has increased the chances of US political or even military interference in Iran. Consequently, the US has enhanced its attempts to weaken and possibly overthrow the Islamic regime as part of its plans to redraw the political and strategic maps of the region. In this regard, the US is using various political and economic instruments to undermine the Iranian government.
Millennium Development Goals and Health
Authors: Nayar K.R. , Razum Oliver
Published: July 2006

The MDGs has been carved out of the UN Millennium Declaration adopted in the fifty-fifth session of the UN General Assembly in September, 2000. Significantly, the MDGs has a bias towards health, education and empowerment. This could be construed as a positive move in international policy as far as the development agenda is concerned. But a closer look at the strategies show that there are several roadblocks towards achieving these goals. The major constraint is the lack of reliable data in developing countries for planning public health programmes. This results in an element of uncertainty and leads to unrealistically high targets which could distort the already fragile health systems in several countries. The selective approach could also spiral intensive drives which might further erode the primary health care system as has happened with the attempt to eradicate polio. The alternative, therefore, is to evolve longer-term, broader, system-based interventions to address the health concerns in the MDGs.
Mr. Nigger
Authors: Jenkins Toby S.
Published: July 2006

The underachievement, lack of inclusion, and backward progression of African American men within American society, and particularly within the educational arena, has once again surfaced as a trend that demands immediate attention. However, the challenges of reversing the negative circumstances facing African American men requires transforming a broad array of social, political, economical, psychological, and educational issues that are deeply rooted in the very power structure of America. On one hand, the society espouses rhetoric of concern and desire to elevate Black males, but, on the other hand, practices a policy of oppression, prejudice, and disregard. Put differently, the experience of the Black man in America seems to be one in which he is called “mister” but is treated with a “niggardly” regard. And the result is the positioning of Black males at the lower rungs of society and their experiencing underachievement in almost allaspectsoflife.
Nepal at the Political Crossroads
Authors: Thapliyal Sangeeta
Published: July 2006

This article critically examines the Government of India's policy of ‘twin pillars’ (constitutional monarchy and multi-party democracy) in Nepal. It asserts that these two forces have not co-existed harmoniously: the inherent contradiction between them is one of the reasons for the political instability in Nepal. Other actors have emerged due to political instability and socio-economic alienation, including protest movements by the janjatis (ethnic nationalities), women, dalits and terains (people from the foothills and plains of Nepal). The Maoist armed movement, by challenging both the monarchy and political parties, has further worsened the situation. This article analyses the strengths and weaknesses of the three main political actors and advocates the adoption of an inclusive political formula for resolving the conflict. Political instability in Nepal has a direct impact upon India, which must therefore proactively use whatever leverage it has in Nepal to help resolve the conflict there.
Dysfunctions and Sub-optimal Behaviours of Rural Development Networks
Authors: Cannarella Carmelo , Piccioni Valeria
Published: July 2006

This article describes the dynamics and impacts of local territorial networks' on the base of the articulation of some examples of varieties of well known pathologies in social systems adjusted to the peculiarities of these local networks. The potential capability of these pathologies to create profound effects in inhibiting link formation, to turn positive links into ineffective or negative ones and to enhance the non-linear system behaviour and results, deeply influences the quality of interactions among network agents. The possibility of providing a correct diagnosis of these network pathologies could provide useful contributions to alerting about actual and potential possibilities of their occurring and in preventing a system collapse caused by a deterioration in the link value and in the eventual link losses.
For and Against Grain Land Use
Authors: Narayanan N.C.
Published: July 2006

A fervent public debate was triggered in Kerala, South India, in July 1997, following a Luddite-type agitation by the agricultural labourers destroying the crops and assets in converted rice fields. The state is against conversion of rice lands, but farmers do it illegally, using the argument of their individual right to opt for the crop of their choice. The agricultural labourers on the other hand, with their strong labour institutions and a left wing government that was sympathetic to their demands, argued for continuance of this activity since rice cultivation is labour intensive. The trade unions argue for the highly labour absorbing activity of rice cultivation and proclaim the labourers’ ‘right to work’ and also raise the environmental and food security arguments for the conservation of rice lands. This article examines the political dimensions of this complex developmental issue.
Do They Know What They Read? Building a Scientific Literacy Measurement Instrument Based on Science Media Coverage
Authors: Brossard Dominique , Shanahan James
Published: July 2006

The authors tested a novel approach to the conceptualization and measurement of a dimension of scientific literacy, the understanding of scientific and technical terms. Through an analysis of the media’s use of scientific and technical terms randomly selected from a scientific dictionary, the authors identified the thirty-one terms most often used in the media. The authors argue that these terms represent what an individual is expected to know within the bounds of normal civic discourse. The measure that was developed therefore represents a conceptualization of a “civically literate” scientific vocabulary that avoids the possible biases that could be associated with a selection of terms based solely on experts’ views. Scientific literacy results obtained through the use of the instrument at the pilot-test level are discussed and contrasted with those obtained when using the National Science Foundation’s scale, which is the most widely cited public scientific literacy measurement instrument based on a more conventional approach to scientific literacy.
Mapping Perceptions of Science in End-of-Century Europe
Authors: Pardo Rafael , Calvo Félix
Published: July 2006

This article offers an alternative to the dominant approach for analyzing public perceptions of science. The authors seek first to clarify to what extent the public at large holds defined attitudes toward science, proposing an “index of cognitive and evaluative distance.” They then present a map of perceptions of science in end-of-century Europe based on correspondence analysis, which displays some of the most salient elements of how science was appropriated in the culture of the time. The map shows that shared social and cognitive characteristics across nations act as unifying forces in public perceptions of science, while the nation variable conserves important singularities. Knowledge of science plays a very significant role in accounting for differences in value judgments about science. “Reservations,” not “promise” items, divide the perceptions of different social groups, suggesting that more weight should be given to the former in future studies.
The Midwest Nursing Centers Consortium Research Network: Translating Research Into Practice
Authors: Anderko Laura , Lundeen Sally , Bartz Claudia
Published: July 2006

Community nursing centers (CNCs) serve the health needs of culturally diverse populations that are often marginalized and likely to experience disparities in health. CNCs utilize innovative models of primary health care that blend traditional medical management with nursing case management and community-based health promotion strategies. This article describes the mission and activities of the Midwest Nursing Centers Consortium Research Network (MNCCRN), a practice-based research network (PBRN) funded by the Agency for Healthcare Research and Quality, and is one of only two federally funded nonphysician primary care PBRNs and the only PBRN in the United States comprising exclusively CNCs. The MNCCRN utilizes Advanced Practice Nurses to deliver primary health care with a particular emphasis on reducing health disparities. The MNCCRN has successfully established a multisite, multistate collaboration for community-based participatory research that will ultimately inform practice, education, and health policy.
Who Will Care for Me? The Debate of Orphanages Versus Foster Care
Authors: O'Sullivan Joanne , McMahon Maria F.
Published: July 2006

The issue of how best to address current problems in the foster care system while at the same time considering past problems with the orphanage concept is a cause of national debate. Among the questions being examined are, is a return to orphanage care feasible and if so, would the re-creation of orphanages benefit the children who would be placed in them. The advanced practice nurse is perfectly situated to participate in this discussion and to advance a theory of harmony by addressing social, economic, and political factors within a patient's environment. Nurse practitioners can also fill an important gap in care for these children who often suffer the consequences of well-intentioned but flawed child care systems.
Controlling dispersed state and exfoliation process of clay in polymer matrix
Authors: Meng X. Y. , Wang Z. , Tang T.
Published: July 2006

In the present review, the authors do not try to provide a comprehensive review of researches on polymer/clay nanocomposites (PCNs), but some examples to demonstrate different exfoliation processes of the clay in various polymer matrixes and the dispersed state of clay. Interaction between polymers and layered silicates plays an important role in adjusting the exfoliation process of layered silicates and the microstructure of polymer nanocomposites. Properties of polymer/layered silicate nanocomposites mainly depend on the dispersed state of layered silicates. The authors will also address the outline of the present research in the direction of PCNs including the discussion of technical problems and their possible solutions.
Surface modification of nanoscale fillers for improving properties of polymer nanocomposites: A review
Authors: Rong M. Z. , Zhang M. Q. , Ruan W. H.
Published: July 2006

Direct incorporation of inorganic nanoscale building blocks into polymers represents a typical way for preparing polymeric nanocomposites. The most important aspect in preparation of nanocomposites through dispersive blending is surface modification of the nanofillers. It is able to increase hydrophobicity of the fillers, enhance interfacial adhesion via chain entanglement or chemical bonding and eliminate the loosen structure of filler agglomerates. The present paper reviews the state of the art of nanoparticles/polymer composites, including the specific surface pretreatment techniques and their applications. Especially, the role of treated nanoparticles and the mechanisms involved in the improvement of mechanical properties and wear resistance of the composites are highlighted.
Nanocomposites of polymers and inorganic particles: Preparation, structure and properties
Authors: Caseri W. R.
Published: July 2006

Although composites with, e.g.nanosized SiO2, TiO2, carbon black or gold are known for a long time, an increasing number of polymer composites comprising inorganic nanoparticles have been described only in the last 15 years. Frequently employed inorganic materials include metals (e.g. gold, silver or copper), semiconductors (e.g. PbS or CdS) or clay minerals (e.g.montmorillonite or vermiculite). In most cases, nanocomposites with spheric or plate like particles have been prepared so far but materials with nanorods (rod like particles, including nanotubes) also attracted attention. The structure of nanocomposites is essentially established by the arrangement of the particles in the polymer matrix. The particles may be dispersed as individual primary particles or as agglomerated particles (secondary particles), and the primary or secondary particles can be arranged randomly or in an ordered or oriented state, depending on the method of nanocomposite preparation and processing (including, e.g. coprecipitation, coevaporation, spin coating or drawing). In order to avoid agglomeration, the nanoparticles are frequently synthesised in situ or applied as surface modified particles, where a spheric inorganic core is preferentially surrounded by a shell composed of organic molecules (core–shell particles). Surface modification is applied routinely for clays, which is of importance for the degree of delamination of the individual silicate layers in the matrix (intercalation or exfoliation). Materials properties of nanocomposites, such as optical transparency, colour (including dichroism), iridescence, catalytic activity or superparamagnetism, can be favourable when compared with analogous composites with larger particles, and these properties may also be influenced by the structure of nanocomposites. The properties of nanocomposites are considered to provide applications in the areas of, e.g. optics, catalysis, electronics, magnetism or mechanics.
Synthesis, characterisation and properties of clay and silica based rubber nanocomposites
Authors: Bandyopadhyay A. , Maiti M. , Bhowmick A. K.
Published: July 2006

Rubbers are high molecular weight polymeric materials, which possess very low interchain attraction, low glass transition temperature and predominantly amorphous nature with low green strength. Fillers like carbon black and silica are frequently added to rubbers in order to improve the mechanical properties of the composites. In recent years, more attention has been paid towards polymer nanocomposites, where the dimension of the inorganic fillers is of the order of nanometre (1–100 nm) and which impart better physicomechanical properties as compared with conventional composites. This chapter is a compendium of the authors’ work on clay and silica filled nanocomposites based on various rubbers. Rubber–clay nanocomposites have been prepared by modification of the naturally occurring Na montmorillonite clay followed by mixing with rubber in solution. Intercalation and/or exfoliation of the clay layers, which depends on a number of factors, has been observed in styrene–butadiene rubber (SBR), acrylonitrile–butadiene rubber (NBR), polybutadiene rubber (BR), brominated polyisobutylene–co-paramethylstyrene (BIMS), ethylene–octene copolymers and thermoplastic elastomers. Predominant intercalation is observed with modified clays in the case of in situ nanocomposites from acrylic monomers. The average dimension (i.e. the width) of the clay layers ranges from 10 to 60 nm in the hybrid nanocomposites, as observed by transmission electron microscopy, scanning electron microscopy and atomic force microscopy studies. Significant improvement in mechanical, dynamic mechanical and barrier properties has been obtained with these clay filled rubber nanocomposites even at very low filler concentration. Sol–gel technique generating in situ silica from the sequential hydrolysis and condensation reactions of tetraethoxysilane (TEOS) has been adopted to synthesise transparent rubber–silica hybrid nanocomposites from polar rubbers like acrylic rubber (ACM) and epoxidised natural rubber (ENR). The sol–gel reaction parameters such as concentration of TEOS, solvents, TEOS/H2O mole ratio, pH value and temperature have profound effects on the morphology of the dispersed silica phase and hence their interaction with the matrix. These factors are crucial in determining various properties like mechanical, dynamic mechanical, rheological and thermal behaviour of the resultant nanocomposites. Some interesting observations have also been recorded in the case of in situ synthesised acrylic copolymer–terpolymer/silica hybrid nanocomposites.
Fracture behaviour of nanoplatelet reinforced polymer nanocomposites
Authors: Boo W.-J. , Liu J. , Sue H.-J.
Published: July 2006

The authors present a review of the recent research effort towards developing a fundamental understanding of fracture behaviour of polymer nanocomposites that contain nanoplatelet fillers. Various toughening mechanisms reported in the literature are summarized and discussed. Within this review, an emphasis is placed on the up to date understanding of how the nanofiller aspect ratio affects the fracture behaviour of polymer nanocomposites. Besides, the effect of nanoplatelet dispersion and exfoliation on the fracture behaviour of polymer nanocomposites will be addressed.
Nanoscale deformation and cracking studies of advanced metal evaporated magnetic tapes using atomic force microscopy and digital image correlation techniques
Authors: Li Xiaodong , Xu Weijie , Sutton M. A. , Mello M.
Published: July 2006

A custom designed microtensile tester was integrated with an atomic force microscopy (AFM) to perform in situ tensile tests on two advanced metal evaporated (ME) magnetic tapes – ME/polyethylene terephthalate (PET) (with PET as a substrate) and ME/polyethylene naphthalate (PEN) (with PEN as a substrate) where the tape surfaces were imaged simultaneously by AFM during tensile loading. The digital image correlation technique was used to process the AFM images and quantitatively measure local, nanoscale deformation for both front coat and back coat of the ME tapes subjected to uniaxial tensile loading. The surface morphology change, strain distribution evolution and crack initiation and propagation during tensile loading are discussed with the structures and mechanical properties of the ME tapes.
Polymer nanocomposites: Current understanding and issues
Authors: Yuan Q. , Misra R. D. K.
Published: July 2006

Polymer nanocomposites, or more appropriately polymer nanostructured materials, represent a radical alternative to the conventional filled polymers and polymer blends, in which discrete constituents on the order of a few nanometres are incorporated in the polymer matrix. In the last decade, the utility of inorganic nanoparticles as additives to enhance polymer performance has been established and now provides numerous commercial opportunities, ranging from advanced aerospace systems to commodity plastics. The incorporation of low volume additions (1–5 wt-%) of highly anisotropic nanoparticles, such as layered silicates or carbon nanotubes, have resulted in property enhancements with respect to the neat polymer that are comparable with that achieved by conventional loadings (15–40 wt-%) of traditional fillers. The lower loadings facilitate processing and reduce component weight. In addition, unique value added properties not normally possible with traditional fillers were also observed, such as high stiffness, reduced permeability, optical clarity and electrical conductivity have been achieved. However, the development of chemical and processing procedures to disrupt the low-dimensional crystallites (tactoids and ropes) to achieve uniform distribution of the nanoelement (layered silicate and single wall carbon nanotube respectively) continues to be a challenge. Even less developed are approaches to provide spatial and orientational control of the hierarchical morphology. There exists an immense potential for polymer nanocomposites, in particular, polypropyelene–clay nanocomposites paving the way for future technologies for the materials community at large.
Crystallisation in polymer nanocomposites
Authors: Jog J. P.
Published: July 2006

Polymer nanocomposites are of interest as they exhibit extraordinary properties compared with the base polymer. The second phase dispersed in the polymer matrix can be carbon nanotubes, semi-conducting inorganic nanoparticles or layer silicates such as clay. Crystallisation in these materials is also of great interest. Polymers exhibit structures at various scales (e.g. lamella, unit cell and spherulites) and the presence of a second phase has a profound effect on crystallisation. General trends observed include acceleration/retardation of crystallisation, changes in spherulite morphology and, in a few cases, changes in the crystal structure. All these observations relate to the presence of a micrometre scale second phase. However, when the dimensions of the second phase are close to the chain dimensions, the effects on crystallisation become particularly interesting. An attempt is made in the present review to address the effect of a nanoscale second phase on aspects such as isothermal and non-isothermal crystallisation, spherulite growth, phase transformation and polymorphism.
Recent advances in polymer/layered silicate nanocomposites: An overview from science to technology
Authors: Okamoto M.
Published: July 2006

Polymer/layered silicate nanocomposites (PLSNCs) offer remarkably improved mechanical and other properties with low inorganic filler loading. The major development in this field has been carried out over the last one and a half decades. However, the authors are far from the goal in terms of understanding the mechanisms of the enhancement effect in the nanocomposites. Continued progress in nanoscale controlling and an improved understanding of the physicochemical phenomena at the nanometre scale have contributed to the rapid development of novel PLSNCs. The present paper describes recent advances in PLSNCs with the primary focus on these advances from basic science to technology.
Crack formation mechanisms in Al2O3/Kovar brazed joint
Authors: Yu Z. S. , Yang P. , Li R. F. , Qi K.
Published: July 2006

Joining of metal to ceramic is difficult owing to the formation of cracks at the interface of brazed joint. In the present paper, the crack forming metallurgical mechanisms is studied primarily. The vacuum brazing experiments of ceramic Al2O3 and Kovar, Ni, Fe or Co metals are all conducted. It can be obtained that the cracks could be formed at the Al2O3–Kovar and Al2O3–Fe joint, but not at the Al2O3–Ni and Al2O3–Co joint. In addition, the interfacial morphology and compound composition near cracks are confirmed. It can be concluded that the formation of intermetallic compound FexTiy is the main reason why cracks formed.
A new criterion for glass forming ability of bulk metallic glasses
Authors: Cai A.-H. , Pan Y. , Gu J. , Sun G.-X.
Published: July 2006

The relationship between Rc and the ratio d/e of Δ d to Δ e is discussed based on five bulk metallic glass (BMG) systems, which show all concave upward parabola relations. The second derivative value of the fitted curve reflects glass forming ability (GFA) and the sensitivity to composition of GFA. The greater the second derivative value, the higher is the GFA and the stronger is the sensitivity to composition. Furthermore, the parabola relations are demonstrated comparing the predicted Rc with the practical Rc in a Mg–Ni–Nd system, and indirectly reasoned by using a Pd–Cu–Si system and a Zr–Ti–Ni–Cu–Be system. Based on the above-mentioned results, the Rcs of other Zr–Al–Ni–Cu alloys are predicted by using the fitted formula. The Rcs are among 4–20 K s−1, which is coherent to the practical preparation condition and indirectly shows reliability of the related parabola relations. The fitted formula can be applied to the cases of the invariability of the primary components of the alloy system. In addition, Trg and Δ Tx parameters are not suitable for the criteria for GFA of BMGs.
Magnetic behaviour of nanocrystalline nickel ferrite: Part 2 – Effect of dilution
Authors: Gubbala S. , Misra R. D. K.
Published: July 2006

The magnetic behaviour of nanocrystalline ferrite is compared with the diluted dispersion systems containing 10–40 wt-% nickel ferrite in a polyethylene matrix. The zero field cooled (ZFC)/field cooled (FC) magnetic measurements [ M( T)] and M( H) measurements suggest strong evidence of interparticle interaction (dipolar surface interactions) which cannot be ignored even in 10 wt-% nickel ferrite–polyethylene diluted system. The general magnetic behaviour of diluted dispersion is similar to that of the undiluted nickel ferrite. However, coercivity, remanence and saturation magnetisation are altered. The changes in the magnetic data are discussed in terms of magnetisation interactions that encourage flux closure configuration.
Microstructural evolution during aging of novel superferritic stainless steel produced by the HIP process
Authors: Ng P. G. , Clarke E. , Khoo C. A. , Fourlaris G.
Published: July 2006

The present paper presents results on the effect of selected heat treatments on the phase stability of an experimental superferritic stainless steel grade produced via the hot isostatic pressing (HIP) process. Both deformed and undeformed specimens were subjected to a variety of heat treatments within the 650–950°C temperature range for aging times of 5 min–1000 h. The temperature region of microstructural consistency for the superferritic stainless steel grade that guarantees optimum mechanical and corrosion properties was determined. Intermetallic phases were found to precipitate under all chosen temperatures, but the length of heat treatment before precipitation occurred varied with temperature and amount of deformation. The formation of minor amounts of austenite was detected in cold deformed specimens heat treated at 850 and 750°C while for the undeformed specimens, such a presence was verified only for specimens heat treated at 850°C. Formation of austenite is always preceded by the formation of an intermetallic phase. It was confirmed as anticipated, that deformation increases the rate of intermetallic phase precipitation. Superferritic steels are natural candidate materials for naval applications and fabrication techniques, such as welding, involve elevated temperatures on components previously deformed during a shaping exercise, therefore it is vital that an assessment of microstructural consistency of this novel powder metallurgy superferritic steel is performed.
Pharmacological activity of sanchi ginseng (Panax notoginseng)
Authors: Ng T B
Published: July 2006

The pharmacological activity and constituents of the sanchi ginseng Panax notoginseng have been reviewed. The bulk of pharmacological findings have been based on the saponins or steryl glycosides, although polysaccharides with immunopotentiating activity, proteins with antifungal, ribonuclease and xylanase activity, and a triacylglycerol (trilinolein) with antioxidant activity have been reported. Protective actions against cerebral ischaemia, beneficial effects on the cardiovascular system, and haemostatic, antioxidant, hypolipidaemic, hepatoprotective, renoprotective and estrogen-like activities have been described. Various methods for authentication of P. notoginseng are available.
Advances and potential applications of chitosan derivatives as mucoadhesive biomaterials in modern drug delivery
Authors: Chopra Shruti , Mahdi Saiqa , Kaur Jasjeet , Iqbal Zeenat , Talegaonkar Sushma , Ahmad Farhan J
Published: July 2006

Pharmaceutical technologists have been working extensively on various mucoadhesive polymeric systems to create an intimate and prolonged contact at the site of administration. Chitosan is one of the most promising polymers because of its non-toxic, polycationic biocompatible, biodegradable nature, and particularly due to its mucoadhesive and permeation enhancing properties. Due to its potential importance in controlled drug delivery applications, pharmaceutical scientists have exploited this mucoadhesive polymer. However, chitosan suffers from limited solubility at physiological pH and causes presystemic metabolism of drugs in intestinal and gastric fluids in the presence of proteolytic enzymes. These inherent drawbacks of chitosan have been overcome by forming derivatives such as carboxylated, various conjugates, thiolated, and acylated chitosan, thus providing a platform for sustained release formulations at a controlled rate, prolonged residence time, improved patient compliance by reducing dosing frequency, enhanced bioavailability and a significant improvement in therapeutic efficacy. We have explored the potential benefits of these improved chitosan derivatives in modern drug delivery.
Anti-plasmodial and anti-leishmanial activity of conformationally restricted pentamidine congeners
Authors: Huang Tien L , Vanden Eynde Jean Jacques , Mayence Annie , Donkor Isaac O , Khan Shabana I , Tekwani Babu L
Published: July 2006

A library of 52 pentamidine congeners in which the flexible pentyldioxy linker in pentamidine was replaced with various restricted linkers was tested for in-vitro activity against two Plasmodium falciparum strains and Leishmania donovani. The tested compounds were generally more effective against P. falciparum than L. donovani. The most active compounds against the chloroquine-sensitive (D6, Sierra Leone) and -resistant (W2, Indochina) strains of P. falciparum were bisbenzamidines linked with a 1,4-piperazinediyl or 1, 4-homopiperazinediyl moiety, with IC50 values (50% inhibitory concentration, inhibiting parasite growth by 50% in relation to drug-free control) as low as 7 nM based on the parasite lactate dehydrogenase assay. Seven piperazine-linked bisbenzamidines substituted at the amidinium nitrogens with a linear alkyl group of 3–6 carbons (22, 25, 27, 31) or cycloalkyl group of 4, 6 or 7 carbons (26, 32, 34) were more potent (IC50 < 40 nM) than chloroquine or pentamidine as anti-plasmodial agents. The most active anti-leishmanial agents were 4,4′-[1,4-phenylenebis(methyleneoxy)]bisbenzenecarboximidamide (2, IC50 ∼ 0.290 μM) and 1,4-bis[4-(1H-benzimidazol-2-yl)phenyl] piperazine (44, IC50∼0.410 μM), which were 10- and 7-fold more potent than pentamidine (IC50 ∼ 2.90 μM). Several of the more active anti-plasmodial agents (e.g. 2,31, 33, 36–38) were also potent anti-leishmanial agents, indicating broad antiprotozoal properties. However, a number of analogues that showed potent anti-plasmodial activity (1, 18, 21, 22, 25–28, 32, 43, 45) were not significantly active against the Leishmania parasite. This indicates differential modes of anti-plasmodial and anti-leishmanial actions for this class of compounds. These compounds provide important structure-activity relationship data for the design of improved chemotherapeutic agents against parasitic infections.
In-vitro and in-vivo studies on a topical formulation of sitamaquine dihydrochloride for cutaneous leishmaniasis
Authors: Garnier Tracy , Brown Marc B , Lawrence M Jayne , Croft Simon L
Published: July 2006

The efficacy of topical formulations of the 8-aminoquinoline, sitamaquine dihydrochloride, in both in-vitro and in in-vivo models of cutaneous leishmaniasis is reported. In-vitro parasite assays confirmed that sitamaquine dihydrochloride was active against a range of Leishmania species that cause either cutaneous or visceral leishmaniasis, with ED50 values against amastigotes over the range of 2.9 to 19.0μM. A range of topical sitamaquine dihydrochloride formulations (anhydrous gel, emulsions) were developed for studies on experimental cutaneous leishmaniasis using only topically acceptable excipients orthose currently undergoing regulatory approval. An uptake study into murine skin confirmed in-vitro skin penetration and retention. Several formulations were tested in-vivo against Leishmania major cutaneous lesions in BALB/c mice. None of the sitamaquine dihydrochloride formulations tested appeared to either slow lesion progression or reduce parasite burden.
Sex-related differences in the gastrointestinal disposition of ivermectin in the rat: P-glycoprotein involvement and itraconazole modulation
Authors: Lifschitz A , Ballent M , Virkel G , Sallovitz J , Lanusse C
Published: July 2006

Ivermectin (IVM), a macrocyclic lactone used as antiparasite agent, has been reported as a P-glycoprotein (P-gp) substrate. The participation of P-gp in the IVM excretion process has been previously demonstrated. Sex-related differences in the kinetic behaviour of some macrocyclic lactone compounds have been observed. The aim of this work was to characterize in-vivo the comparative gastrointestinal disposition of IVM in male and female rats. The sex-related influence on the itraconazole (ITZ) modulation of P-gp-mediated IVM intestinal transport was also assessed. Sixty Wistar rats (30 male, 30 female) received IVM alone or co-administered with ITZ. Rats were killed between 6 and 72h after treatment and blood, gastrointestinal tissues and lumen contents were collected. IVM concentrations were determined by high performance liquid chromatography. Substantial sex-related differences in the IVM disposition kinetics were observed. Higher IVM systemic availability was observed in female rats. The ITZ-mediated modulation of the IVM disposition kinetics had a differential impact between male and female rats. Co-administration with ITZ resulted in a marked increase in the IVM concentrations in the wall tissue from different portions of the gastrointestinal tract of male rats. The presence of ITZ induced drastic sex-related changes on the P-gp-mediated IVM gastrointestinal disposition.
Everolimus alters imatinib blood partition in favour of the erythrocyte
Authors: Prenen Hans , Guetens Gunther , De Boeck Gert , Highley Martin , van Oosterom Allan T , de Bruijn Ernst A
Published: July 2006

The signal transduction inhibitor imatinib is one of the latest breakthroughs in cancer pharmacotherapy. It is administered orally over prolonged periods of time for the treatment of gastrointestinal stromal tumours. Routine therapeutic drug monitoring of blood plasma versus red blood cells over several years by liquid chromatography coupled tandem mass spectrometry has highlighted a very intriguing phenomenon. Imatinib plasma availability decreases dramatically owing to a significant shift in the partition ratio of red blood cells versus plasma. The shift is enforced by combination with everolimus, another signal transduction inhibitor. These data warrant routine erythrocyte versus plasma monitoring to prevent unexpected alterations in drug efficacy during long-term treatment.