bluuebunny/crossref_metadata_2025 huggingface dataset:
Filtering for medical news items
Authors: Watters Carolyn , Zheng Wanhong , Milios Evangelos
Published: January 2005

In this paper we describe recent work toprovide a filtering service for readers interested in medically related news articles from online news sources. The first task is to filter out the nonmedical news articles. The remaining articles, the medically related ones, are then assigned MeSH headings for context and then categorized further by intended audience level (medical expert, medically knowledgeable, no particular medical background needed). The effectiveness goals include both accuracy and efficiency. That is, the process must be robust and efficient enough to scan significant data sets dynamically for the user at the same time as provide accurate results. Our primary effectiveness goal is to provide high accuracy at the medical/nonmedical filtering step. The secondary concern is the effectiveness of the subsequent grouping of the medical articles into reader groups with MeSH contexts for each paper. While it is relatively easy for people to judge that an article is nonmedical or medical in content it is relatively difficult to judge that any given article is of interest to certain types of readers, based on the medical language used. Consequently the goal is not necessarily to remove articles of higher readership level but rather to provide more information for the reader.
Communities of practice with and without information technology
Authors: Hara Noriko , Kling Rob
Published: January 2005

Despite strong interest among practitioners and scholars, the study of communities of practice (CoPs) and Information Technology (IT) is short of empirical research. This paper presents a theoretical framework for communities of practice and provides alternative perspectives on IT supports for communities of practice. The framework was developed based on the literature and ethnographic case studies of communities of practice within two organizations. The study examines how people share and construct their knowledge and how they use collaborative IT to support work practices in two organizations. The surprising finding is that the groups that used IT most intensively had the least well‐developed CoPs. The results of the study would inform practice and research in Knowledge Management.
Cross‐cultural preference of visual information in primary school ESL children
Authors: Copper Linda Z.
Published: January 2005

This paper presents a pilot study that investigates cross‐cultural preferences of visual information in primary school children for whom English is a second language. Recently immigrated children from three different countries were shown twentyfour sets of three pictorial representations of the same concept, each published in a different country, one of these being the country of origin of some of the children. Children were asked to identify the concept represented in each set, select the best representation of the concept, and give a reason for their preference. Results are presented and discussed in terms of developmental considerations, background of participants, origin of publication, and graphic qualities of representations.
Once found, what then? A study of “keeping” behaviors in the personal use of Web information
Authors: Jones William , Dumais Susan , Bruce Harry
Published: January 2005

This observational study investigates the methods people use in their workplace to organize web information for re‐use. In addition to the bookmarking and history list tools provided by web browsers, people observed in our study used a variety of other methods and associated tools. For example, several participants emailed web addresses (URLs) along with comments to themselves and to others. Other methods observed included printing out web pages, saving web pages to the hard drive, pasting the address for a web page into a document and pasting the address into a personal web site. Differences emerged between people according to their workplace role and their relationship to the information they were gathering. Managers, for example, depended heavily on email to gather and disseminate information and did relatively little direct exploration of the Web. A functional analysis helps to explain differences in “keeping” behavior between people and to explain the overall diversity of methods observed. People differ in the functions they require according to their workplace role and the tasks they must perform; methods vary widely in the functions they provide. The functional analysis can also help to assess the likely success of various tools, current and proposed.
Innovative uses of knowledge management to maintain competitive advantage. Sponsored by SIG MGT, SIG KM
Authors: Edgar Bill , Bergeron Pierrette , Miller Jerry , Breeding Bret , Shelfer Katherine , Procaccino J. Drew , Jones Yolanda , Casale AnnaMarie Del , White Larry Nash , Colby Beverly
Published: January 2005

This panel will explore innovative applications of Knowledge Management to give conference attendees a peek at the next generation of KM from the research perspective, but including a practical spin. Some of the topics addressed will be the application of the concept of “boundary spanning” to support knowledge management innovation. Another will address the use of unfamiliar workflow models to improve knowledge transfer. The use of competitive intelligence systems technology to guide knowledge management software development will be explored, as well as other examples of the linking of competitive intelligence to knowledge management. The emphasis is on maintaining competitive edge through KM.
Digital divide II: Global vs. local content. Sponsored by SIG III
Authors: Xu Hong , Armstrong Peter , Shadrach Basheerhamad , Sealy Wendy , Stansbury Mary
Published: January 2005

At ASIST 2001 conference, a digital divide panel session on issues, policies, and case studies were very well‐received. This year, as a followup, three presenters will discuss how to bridge digital divide at local, regional, and global levels.
Access to large spoken archives: Uses and technology. Sponsored by SIG VIS
Authors: Soergel Dagobert , Gustman Samuel , Kornbluh Mark , Ramabhadran Bhuvana , Goldman Jerry
Published: January 2005

With recent advances in information technology, digital archiving is emerging as an important and practical method for capturing the human experience. Large amounts of spoken materials and audiovisual materials in which speech is an important component are becoming available. This panel will discuss the uses of these mateials for education, information retrieval and dissemination, and research, the requirements that arise from these uses, and speech recognition and retrieval technologies being developed to meet these requirements. These materials have tremendous potential for enriching the presentation of information in education, newscasts and documentaries, but retrieval from and access to these large repositories pose significant challenges. The panel will provide an overview of these issues.
Multicultural aspects of information organization and access. Sponsored by SIG III
Authors: Zhang Yin , Skrzeszewski Stan , Subrahmanyam Bhagirathi , Metoyer Cheryl , Leroy Nathalie , Caidi Nadia
Published: January 2005

The globalization of information creates an involving multicultural environment that poses great opportunities and challenges for information organization and access. In this panel session, a group of experts will present their insight and research to illustrate how they address these opportunities and challenges.
Virtual reference services: Exploring the open source options. Sponsored by SIG DL, SIG ED, SIG LAN, SIG STI
Authors: Tang Rong , Calarco Pascal V. , Fagan Jody Condit , Stormont Sam , Casson Rob
Published: January 2005

Virtual reference services, particularly in academic libraries, are coming to be regarded as essential. LSSI and LivePerson are among the well‐established commercial vendors of virtual reference systems. However, interesting open source efforts offer libraries the power to customize their virtual reference services to best meet their institution's needs better than many commercial packages can. This session provides an overview of three open‐source packages, discusses how they are being used, and examines their role in providing academic reference services.
Digital libraries supporting distance education. Sponsored by SIG DL, SIG ED, SIG PUB
Authors: Calarco Pascal V. , Griffiths Joséa‐Marie , Tirrell Tim , Long Phillip D. , Walker Ed
Published: January 2005

Use of online courseware in supporting distributed and distance learning in higher education is maturing in terms of both technology and organizational readiness. However, faculty and institutions are concerned with receiving equal credit for creating and delivering online courses. For both, peer review is important, while faculty have additional concern over workload and promotion and tenure considerations. Standards, interoperability, and collaboration will increase the legitimacy of their efforts. This session will present the work of three initiatives that are developing standards for courseware repositories, interoperability between courseware products, and collaborative efforts to produce and share courseware for member institutions and others.
Mapping the knowledge. Sponsored by SIG MET, SIG VIS
Authors: Chen Chaomei , McCain Katherine , Boyack Kevin W. , Lin Xia , Morris Steven A.
Published: January 2005

This technical panel session aims to bring together researchers and practitioners who are interested in exploiting quantitative and qualitative approaches to tracking and visualizing the development of science and technology, with special emphasis on the potential of information visualization techniques. The aim is to bring home some issues that have been the central concern of information scientists so as to promote cross‐disciplinary communications on topics such as scholarly communication, science studies, and knowledge discovery and information visualization.
Digital intermediation: An exploration of user and intermediary perspectives
Authors: Southwick Sílvia Barcellos
Published: January 2005

In recent years major efforts have been made in developing digital library technologies for information seeking. This is an evolving area with many challenges for both practitioners and researchers. In particular, at the current stage in digital library development, users may still be unable to find relevant resources to solve their information problems without the help of human intermediaries. Intermediaries have traditionally served an important role in assisting library system users. Following on this tradition, information services have begun to offer human‐mediated reference to assist remote users. Despite this trend, there remains an inadequate understanding of the effectiveness of these systems. This paper reports on an exploratory case study of intermediation in a hospital digital library information service. The study focused on intermediation where user‐intermediary communications were conducted through an asynchronous text‐based digital medium. The goal of the research was in describing and gaining a further understanding of the processes of intermediation. The overall approach was naturalistic with grounded theory providing a framework for data analysis. The contributions of the study are evidenced in a descriptive framework of nine categories of factors perceived as affecting digital intermediation. The paper concludes with directions for future research.
Finding aid as interface? Enhancing K‐12 access to digitized cultural heritage resources through adaptive systems technology: An exploratory study
Authors: Besser Howard , Afnan‐Manns Sheila , Stieber Dale Ann , Griest Bryan , Turnbow Dominique , Dorr Aimée
Published: January 2005

To what extent must diverse users adapt themselves to singular one‐interface systems, and in what ways does this impede access and use? In a perfect world of adaptive systems, backend architecture structuring digital information would be accessible through multiple user interfaces that support the literacy levels, technological capabilities and other characteristics of different user groups. Collaborating with the California Digital Library, usability testing was conducted with 4th and 12th graders to compare the effectiveness of an existing finding aid‐based interface with a newly developed prototype interfaco in retrieving cultural heritage information. Findings inform the growing number of efforts by cultural heritage communities—including libraries, archives, museums, and community organizations—to create broader access to their rich resources through digitization.
MOAC II user evaluation: Making museum content useful
Authors: Gilliland‐Swetland Anne , Chandler Robin L. , White Layna
Published: January 2005

Museums and the Online Archive of California II User Evaluation (MOAC II) examines digital museum content for use in education and research. MOAC II is an advancement of MOAC (1998‐present), a major collaboration involving integration of collection descriptions and images. The evaluation targets four user constituencies: K‐12 teachers, university students, academics in the humanities and social sciences, and museum professionals, librarians and archivists. MOAC II examines why users use digital museum objects, what users need to understand about museum objects as sources of information and evidence, and how digital museum objects might be used to enhance classroom teaching at K‐12, undergraduate, and graduate levels. MOAC II collaborators will report on progress made in the first year of this collaborative research project.
A text corpus approach to an analysis of the shared use of core terminology
Authors: Patrick Timothy B. , Reid John C. , Sievert MaryEllen , Rice Frances Ellis , Gigantelli James W. , Schiffman Jade S. , Shelton Mark E.
Published: January 2005

We sought to investigate the shared use of core Ophthalmology terms in the domains of Ophthalmology, Family Practice and Radiology. A random sample of 450 terms was selected from the terms submitted as Ophthalmology terms in the NLM/AHCPR Large Scale Vocabulary Test. Two expert Ophthalmologists rated each term as Ophthalmic or non‐Ophthalmic. When both raters agreed that a term was Ophthalmic, it was treated as a core Ophthalmology term for purposes of the study. We searched for the core terms in a text corpus of 38,695 MEDLINE abstracts covering 1970–1999 from journals representing the three domains of Ophthalmology, Radiology, and Family Practice. We compared proportions of abstracts from each domain for each term. We examined overlap of confidence intervals for proportions of abstracts for each core term and domain. Core Ophthalmology terms were used significantly more by Ophthalmology than by Radiology, or by Family Practice.
User centric design and implementation of a digital historic costume collection
Authors: Martin Kathi , Lin Xia , Lunin Lois
Published: January 2005

This paper reports on the human factors considered in the design and implementation of a digital museum for historic costume. Starting with a thorough elicitation and analysis of the qualitative as well as the functional needs of its users, an evolutionary prototype has been developed for a model of digital archiving that delivers a gratifying web experience, visually and interactively. The prototype is a standards and best practices based information system with the interface designed to be accessible for anyone with World Wide Web experience. An online category thesaurus has been developed to enhance the classification of, and access to, images and data about historic costume. Standards and protocols of the Open Archive Initiative (OAI) and the Museums Online Archive California (MOAC) are being implemented to broaden the user base by making the system portable and extendible.
Fitting users' needs into Web‐based area studies resources: A study of the Latin American Network Information Center (LANIC)
Authors: Letalien Bethany Lynn , Chen Hsin‐Liang
Published: January 2005

The Latin American Network Information Center (LANIC, http://lanic.utexas.edu/) is an academic Website that houses various databases and similar projects and provides directory access to sites in and about Latin America. Exploratory research into the site's usability was performed in October and November of 2002 through surveys, card sorting, and observation. Problems addressed included users' (in)ability to identify and use databases, (in)adequacy of the site's and the directory's hierarchical structures, (in)adequacy of subject terms, and page size. Several open‐ended questions were used to solicit criticisms and suggestions from users. Overall, users were successful in using the Website and expressed satisfaction with it, but some problems, both major and minor, were uncovered.
The role of narrative in understanding digital video: An exploratory analysis
Authors: Wilkens Todd , Hughes Anthony , Wildemuth Barbara M. , Marchionini Gary
Published: January 2005

Narrative is perhaps the oldest and most widely used form for organizing information and human experience, thus, it is not surprising that there is a significant body of research concerning narrative and its importance to comprehension and understanding. One important outcome of this research is the concept of narrative intelligence, the human tendency to fit experience into narrative form. This research is extremely relevant to information seeking in general and sense‐making

Throughout the paper we are referring to the general process of sense‐making (i.e. how people make sense of and construct meaning in their worlds) and not to the Sense‐Making methodology of Dervin (1992).

in particular. This paper outlines the basic principles and research supporting the concept of narrative intelligence and its applicability to the ways in which people make sense of digital video. We explore relevant theory and research in sense‐making, surrogates, narrative, and narrative intelligence and then present the preliminary results of two research studies. The first clarifies and operationalizes the concept of narrative as it relates to video. The second demonstrates how narrativity can have significant effects on information seeking and sense‐making in digital video. Results from these studies have implications for how syntactic form can be used as a means of indexing digital video.
Multitasking Web searching and implications for design
Authors: Ozmutlu Seda , Ozmutlu H. C. , Spink Amanda
Published: January 2005

This paper presents findings from a study of users multitasking searches on Web search engines. A user's single session with a Web search engine may consist of seeking information on single or multiple topics. Limited research has focused on multitasking search and the implications for Web design. Incidence of multitasking search by AlltheWeb.com and Excite Web search engine users were filtered from transaction logs. Findings include: (1) multitasking Web searches are a noticeable user behavior, one tenth of Excite users and one third of AlltheWeb.com users conducted multitasking searches, (2) multitasking search sessions are longer than regular search sessions in terms of queries per session and duration, (3) both Excite and AlltheWeb.com users search for about three topics per multitasking session and submit about 4–5 queries per topic, and (4) there is a broad variety of search topics in multitasking search sessions. The implications of our findings for Web design and further research are discussed.
Pioneering women in information science. Sponsored by SIG HFIS
Authors: Bonnici Laurie J. , Furner Jonathan , Justice Alexander , La Barre Kathryn , Miksa Shawne D. , Plant Helen
Published: January 2005

This Panel examines the lives and work in information science of six pioneering women – Helen Brownson, Elfreda Chatman, Edith Ditmas, Margaret Egan, Barbara Kyle, and Phyllis Richmond. In careers that collectively span more than seventy years, these women have had tremendous impact on our field. Yet the full extent of their influence has often gone unrecognized in the secondary literature. In this session, we will seek to reveal these pioneers' contributions in such areas as documentation, classification, information retrieval, and social epistemology; to identify reasons for the historical neglect of some of these contributions; and to provide links to our past that will enhance our understanding of current theory and practice in the field of library and information science.
The death of the user. Sponsored by SIG HFIS, CRIT
Authors: Rosenbaum Howard , Davenport Elisabeth , Lievrouw Leah A. , Day Ronald E.
Published: January 2005

This panel critically investigates the theoretical and practical issues involved with the wellestablished concept of “the user” in Library and Information Science. It suggests that digital information and communication technologies and systems are theoretically and practically undermining this concept, a concept that was already weak in its ability to fully account for agency in many events of information and knowledge.
Transborder data flow: Implications for information dissemination and policies between the U.S., Canada and Mexico. Sponsored by SIG IFP, III
Authors: Warwick Shelly , Caidi Nadia , Bergeron Pierrette , Dufour Christine , Cortes Jesus , Rumble John
Published: January 2005

The convergence of computing and networking has affected the ways in which people live, work and learn; the way institutions operate; and raised new issues and challenges for governments. National and global initiatives have been implemented to address the blurring of boundaries ‐geographical and political‐caused by electronic data transfer over these global networks. The flow of electronic data and digital content across jurisdictional lines calls for novel ‐or updated‐ laws and regulatory solutions (e.g., data protection, privacy, content regulation, etc.).

This panel offers a comparative analysis of national laws and policies regulating the transport of data across national boundaries, with a special focus on the implications for information dissemination and access. A series of panelists from a variety of backgrounds and perspectives will explore these issues and describe how these are framed and debated in the United States, Canada and Mexico. The discussion should both inform and entice the audience to reflect on and pursue these timely problems.
The public domain under pressure. Sponsored by SIG IFP, III, STI
Authors: Hodge Gail , Uhlir Paul , Arunachalam Subbiah , Moritz Tom
Published: January 2005

Public domain information, whether limited to judicial decisions or extended to all government‐authored or sponsored works, has been expounded as a means of ensuring a knowledgeable citizenry, promoting economic advancement, and ensuring that publicly funded information is not “double taxed”. However, the public domain has come under increased pressures as the global information economy changes. The speakers in this session will address these pressures from a number of different national and disciplinary views.
Student award‐winning papers. Sponsored by SIG ED.
Authors: Wildemuth Barbara M.
Published: January 2005

Winners of the three student award competitions will be invited to present their work to the ASIST audience. They include winners of the Pratt‐Severn Best Student Research Paper Award, the ISI Doctoral Dissertation Scholarship, and the UMI Doctoral Dissertation Award.
2nd Global Information Village Plaza ‐ Connecting multi‐cultural, multi‐lingual and multi‐media universes. Sponsored by SIG III, IFP
Authors: Caidi Nadia , Menou Michel J.
Published: January 2005

Building on the success of the 2002 Global Information Village Plaza, this new edition maintains its interactive format (aimed at giving ASIS&T members an opportunity to express their personal views about the challenges and opportunities that the so called “information society” represents in their personal and professional lives) and adds a new multimedia dimension. New features include an edited video segment showcasing individuals and communities from around the world and the ways in which they frame the debate; another feature is the international contest for Best Graphic Art piece related to the overarching topic of the Global Information Village Plaza. Moreover, in an attempt to widen the debate, all the SIGs will be contacted and asked to submit their reflections on the issues debated. A complete web resource dedicated to the Global Information Village Plaza will be developed that includes results from the previous year's discussions; identification of recurring themes; areas where more research is needed; links to existing resources, initiatives, and policy statements. The discussion will focus on the main issues identified in the 1st Global Information Village Plaza. To keep up with the spirit of the Global Information Village Plaza, personal submission of position statements will be sought from the information professional community around the globe. The process is due to run from May through October 2003. It will include posting and discussion by those interested of short position statements on ASIST&T and other professional listservs. Selected statements will be summarized in a series of posters during a special session. During the session, participants in the Annual Meeting will be invited to first browse through the posters and comment in writing. A general discussion will later on take place. SIG/III plans to publish a summary of the process and its outcome.
Information behavior in everyday life: Research on street‐level sex workers, new immigrants, and hair stylists. Sponsored by SIG USE
Authors: Fisher Karen E. , Baker Lynda M. , Brown Christine
Published: January 2005

Little research has focused on the information behavior of the general public (Julien & Duggan, 2000). In this session we report findings on how information is sought and used as part of everyday life by three distinct groups: (1) street‐level sex workers, (2) new immigrants, and (3) hairdressers.
Leveraging the power of diversity to create effective and empowering technology
Authors: Nair Sarita , Flansburg Sundra , Hanson Katherine
Published: January 2005

Very little existing research has comprehensively examined the impact of new technologies on teaching and learning. Looking beyond the “training” of users to access and use ICTs, the work of the Gender, Diversities, and Technology Institute looks at how emerging technologies can be more effectively utilized to meet the needs of diverse learners—in effect humanizing technology. This paper reviews learning arising from a range of the Institute's research and practice, including large‐scale digital resource development that builds in accessibility and usability, online learning that engages learners and other stakeholders in creating equitable learning experiences, and e‐communications that incorporates and responds to issues arising at the intersection of gender and culture. Together, this work has raised new questions that lead to a re‐examination of the relationship between “users” and “developers,” as well as a need to look at the development process itself. The need to not only engage diverse users in the design and development process, but to also actively search for and build on the different starting points that arise from these diverse users is at the core of work to humanize technology and its impacts.
Targeted access for varied audiences to integrated, heterogeneous digital information resources
Authors: Alemneh Daniel Gelaw , Hartman Cathy Nelson , Hastings Samantha Kelly
Published: January 2005

Portals have emerged as an important tool for facilitating single‐point‐access to digital resources. This poster presents an overview of the University of North Texas (UNT) Libraries' “Portal to Texas History” project, which aims to integrate and ensure long‐term access to large quantities of heterogeneous digital resources from many different institutions. The UNT library is undertaking the leadership role by creating the application framework, setting project standards and guidelines, and facilitating collaborative efforts for content building. Also discussed are expanded services for targeted audiences, project approaches to preservation challenges, collaboration benefits, and other issues that emerged in the process of building a platform for the portal system.
Involvement of Rho‐kinase in the contractile mechanism of human ureteral smooth muscle
Authors: Hong Sung Kyu , Kwak Cheol , Chang Jeong Byung , Kim Bong Sub , Kim Hyeon Hoe
Published: February 2005

Aim

Even though many agents have been implicated as modulators of ureteral contractile activity, the exact mechanisms that control human ureteral smooth muscle contractility have yet to be clearly defined. Recently, Rho‐kinase has been reported to be involved in the contractile mechanism of smooth muscles in various organs. In the present study, we sought to investigate whether or not Rho‐kinase is expressed in the human ureteral smooth muscle, and to study its role regarding human ureteral smooth muscle contractility.

Methods

Ureteral samples were obtained from human adult subjects undergoing radical nephrectomy. Immunohistochemistry and Western blotting were performed to determine the presence of Rho‐kinase in human ureter. Functional studies were performed with human ureteral strips suspended in organ bath, and the effects of Y‐27632, a specific inhibitor of Rho‐kinase, on baseline tensions, spontaneous contractions, and electrical field stimulation (EFS)‐induced contractions were analyzed.

Results

The results of immunohistochemistry and immunoblotting study indicated that Rho‐kinase is present in human ureteral smooth muscle. In functional analysis, Y‐27632 was shown to decrease the baseline tension. And, both spontaneous and EFS‐induced contractile responses of human ureteral strips were attenuated by Y‐27632 in dose‐dependent manners.

Conclusions

For the first time, the results of the present study indicate that Rho‐kinase is present in human ureteral smooth muscle and may play an important role in the intricate mechanism of human ureteral contractility and tone. Neurourol. Urodynam. 24:136–141, 2005. © 2005 Wiley‐Liss, Inc.
Polydimethylsiloxane‐magnetite nanoparticle complexes and dispersions in polysiloxane carrier fluids
Authors: Wilson K. S. , Goff J. D. , Riffle J. S. , Harris L. A. , St Pierre T. G.
Published: January 2005

Dispersions of sterically stabilized magnetite nanoparticles in polydimethylsiloxane (PDMS) carrier fluids have been prepared for potential biomedical applications. Trivinylsiloxy‐terminated PDMS was functionalized with mercaptoacetic acid or mercaptosuccinic acid to afford PDMS stabilizers containing either three or six carboxylic acid groups, respectively, at one chain‐end. Magnetite nanoparticles were synthesized by a chemical co‐precipitation reaction of FeCl2 and FeCl3 with hydroxide at pH 9–10. Subsequently, the PDMS stabilizers were adsorbed onto the magnetite nanoparticle surfaces via the carboxylate groups in an interfacial reaction at an acidic pH. The complexes were characterized with transmission electron microscopy to establish an average particle diameter of 7.4 ± SD 1.7 nm and approximately spherical shape. Complexes containing up to 67 wt% magnetite were prepared using these PDMS stabilizers, resulting in maximum saturation specific magnetizations of ∼50 emu g−1. The polymer‐magnetite nanoparticle complexes could be dispersed in PDMS oligomers to afford polysiloxane ferrofluids. Copyright © 2005 John Wiley & Sons, Ltd.
Mechanical creep and recovery of poly(styrene‐b‐ethylene/butylene‐b‐styrene) (SEBS), sulfonated SEBS (sSEBS), and sSEBS/silicate nanostructured materials
Authors: Blackwell Richard I. , Mauritz Kenneth A.
Published: January 2005

Creep and recovery of poly(styrene‐b‐ethylene/butylene‐b‐styrene) (SEBS) and sulfonated SEBS (sSEBS) materials having various percent sulfonation, some of which were exchanged with monovalent counterions, and sSEBS/silicate hybrids, were investigated. Explanations offered for tensile and shear creep reduction for low degrees of sulfonation involved hydrogen bonding between SO3H groups and/or observed frustrated morphologies. At higher sulfonation levels, an increase in overall percent strain was rationalized in terms of either a more distinct EB phase morphology, or to residual water bound to sulfonic acid groups. This effect was also observed when the acid form materials were ion‐exchanged with monovalent counterions. The behavior of silicate‐containing systems is situational and less understood. An equation for a modified Burgers viscoelastic model was seen to fit the creep data very well. Copyright © 2005 John Wiley & Sons, Ltd.
Synthesis of methyl methacrylate and N‐aryl itaconimide block copolymers via atom‐transfer radical polymerization
Authors: Anand Vishal , Agarwal Seema , Greiner Andreas , Choudhary Veena
Published: January 2005

The paper describes the synthesis of block copolymers of methyl methacrylate (MMA) and N‐aryl itaconimides using atom‐transfer radical polymerization (ATRP) via a poly(methyl methacrylate)–Cl/CuBr/bipyridine initiating system or a reverse ATRP AIBN/FeCl3·6H2O/PPh3 initiating system. Poly(methyl methacrylate) (PMMA) macroinitiator, ie with a chlorine chain‐end (PMMA‐Cl), having a predetermined molecular weight (Mn = 1.27 × 104 g mol−1) and narrow polydispersity index (PDI = 1.29) was prepared using AIBN/FeCl3·6H2O/PPh3, which was then used to polymerize N‐aryl itaconimides. Increase in molecular weight with little effect on polydispersity was observed on polymerization of N‐aryl itaconimides using the PMMA‐Cl/CuBr/Bpy initiating system. Only oligomeric blocks of N‐aryl itaconimides could be incorporated in the PMMA backbone. High molecular weight copolymer with a narrow PDI (1.43) could be prepared using tosyl chloride (TsCl) as an initiator and CuBr/bipyridine as catalyst when a mixture of MMA and N‐(p‐chlorophenyl) itaconimide in the molar ratio of 0.83:0.17 was used. Thermal characterization was performed using differential scanning calorimetry (DSC) and dynamic thermogravimetry. DSC traces of the block copolymers showed two shifts in base‐line in some of the block copolymers; the first transition corresponds to the glass transition temperature of PMMA and second transition corresponds to the glass transition temperature of poly(N‐aryl itaconimides). A copolymer obtained by taking a mixture of monomers ie MMA:N‐(p‐chlorophenyl) itaconimide in the molar ratio of 0.83:0.17 showed a single glass transition temperature. Copyright © 2005 Society of Chemical Industry
Mechanical properties of woodflour/linseed oil resin composites
Authors: Mosiewicki M , Borrajo J , Aranguren MI
Published: January 2005

The purpose of this project was to obtain new composites using filler and resin obtained from renewable resources, combining low cost and good mechanical properties. The matrix consisted of a polyester resin synthesized from linseed oil and further crosslinked with styrene in a peroxide‐initiated reaction. Composite materials made from the unsaturated polyester/styrene thermoset and containing various percentages of woodflour were prepared and tested. The relationships between the filler content, porosity fraction, and mechanical properties of the materials were evaluated. The bending modulus and strength of the composites were significantly higher than that of the matrix. Simple models were successfully applied in the analysis of the mechanical properties of the materials. The porosity effect was also considered in the model predictions. The results of the mechanical and dynamic mechanical tests, the scanning electron micrographs of surface fractures, and the adhesion parameter calculated from the strength models all indicated that there was a strong interfacial interaction between matrix and filler. Copyright © 2005 Society of Chemical Industry
Crosslinked polyurethanes with shape memory properties
Authors: Hu Jinlian , Yang Zhuohong , Yeung Lapyan , Ji Fenglong , Liu Yeqiu
Published: January 2005

A series of shape memory polyurethanes (SMPUs) was prepared from polycaprolactone diol (PCL) 4000, 1,4‐butanediol (BDO), dimethylol propionic acid (DMPA), triethylamine, and 4, 4′‐diphenylmethane diisocyanate (MDI), to which excess MDI or glycerin were added to obtain crosslinked shape memory polyurethanes. Their mechanical, thermomechanical, thermal and shape memory properties were investigated by using differential scanning calorimetry (DSC), Fourier‐transform (FT‐IR) spectroscopy, dynamic mechanical analysis (DMA) and tensile testing. The results showed that crosslinked SMPUs have better thermal and thermomechanical properties than those prepared from linear polyurethanes and display good shape memory effects. Copyright © 2005 Society of Chemical Industry
High chemoselectivity of CS dipolarophile in 1,3‐dipolar cycloaddition of nitrilimines and 1,2,4‐triazepin‐5‐one derivatives: experimental, theoretical and X‐ray study
Authors: Azzouzi Saida , El Messaoudi Malika , Esseffar M'hamed , Jalal Rachid , Cano Félix H. , del Carmen Apreda‐Rojas María , Domingo Luis R.
Published: February 2005

Substituted 2,7‐dimethyl‐3‐thioxo‐3,4,5,6‐tetrahydro‐2H‐[1,2,4]triazepin‐5‐one reacts as a dipolarophile with several N‐aryl‐C‐ethoxycarbonylnitrilimines, in equimolar quantities, to give, in all cases, two types of products: diethyl 3‐(p‐aryl)‐2‐[N′‐(p‐aryl)‐N′‐(2′,7′‐dimethyl‐5′‐oxo‐5′,6′‐dihydro‐2H‐[1,2,4]triazepin‐3′‐yl)‐hydrazino]‐2,3‐dihydro[1,3,4]thiadiazole‐2,5‐dicarboxylate (3a–3c in 20–25% yield) and ethyl 4‐(p‐aryl)‐5‐imino‐1,4‐dihydro[1,3,4]thiadiazole carboxylate (4a–4c in 45–50% yield). When 1:2 stoichiometry was used, the formation of product 3 (50%) was favoured. The reaction is entirely chemo‐ and regioselective. The structures of the compounds obtained, where aryl stands for p‐chloro‐phenyl (3b) in the first type and for tolyl (4a) in the second type, were determined by X‐ray crystallography and analysed by spectral methods (NMR and mass spectroscopy). The global and local electrophilicity/nucleophilicity have been analysed to rationalize the chemical reactivity of the reactants. Copyright © 2005 John Wiley & Sons, Ltd.
Stereospecific sequential block copolymerizations of styrene and 1,3‐butadiene with a C5Me5TiMe3/B(C6F5)3/Al(oct)3 catalyst
Authors: Ban Hoang The , Tsunogae Yasuo , Shiono Takeshi
Published: February 2005

This article reports a new methodology for preparing highly stereoregular styrene (ST)/1,3‐butadiene (BD) block copolymers, composed of syndiotactic polystyrene (syn‐PS) segments chemically bonded with cis‐polybutadiene (cis‐PB) segments, through a stereospecific sequential block copolymerization of ST with BD in the presence of a C5Me5TiMe3/B(C6F5)3/Al(oct)3 catalyst. The first polymerization step, conducted in toluene at −25 °C, was attributed to the syndiospecific living polymerization of ST. The second step, conducted at −40 °C, was attributed to the cis‐specific living polymerization of BD. The livingness of the whole polymerization system was confirmed through a linear increase in the weight‐average molecular weights of the copolymers versus the polymer yields in both steps, whereas the molar mass distributions remained constant. The profound cross reactivity of the styrenic‐end‐group active species with BD toward ST led to the production of syn‐PS‐b‐cis‐PB copolymers with extremely high block efficiencies. Because of the presence of crystallizable syn‐PS segments, this copolymer exhibited high melting temperatures (up to 270 °C), which were remarkably different from those of the corresponding anionic ST–BD copolymers, for which no melting temperatures were observed. Scanning electron microscopy pictures of a binary syn‐PS/cis‐PB blend with or without the addition of the syn‐PS‐b‐cis‐PB copolymers proved that it could be used as an effective compatibilizer for noncompatibilized syn‐PS/cis‐PB binary blends. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1188–1195, 2005
Poly(lactic acid)/organoclay nanocomposites: Thermal, rheological properties and foam processing
Authors: Di Yingwei , Iannace Salvatore , Maio Ernesto Di , Nicolais Luigi
Published: February 2005

In this study, polymer nanocomposites based on poly(lactic acid) (PLA) and organically modified layered silicates (organoclay) were prepared by melt mixing in an internal mixer. The exfoliation of organoclay could be attributed to the interaction between the organoclay and PLA molecules and shearing force during mixing. The exfoliated organoclay layers acted as nucleating agents at low content and as the organoclay content increased they became physical hindrance to the chain mobility of PLA. The thermal dynamic mechanical moduli of nanocomposites were also improved by the exfoliation of organoclay; however, the improvement was reduced at high organoclay content. The dynamic rheological studies show that the nanocomposites have higher viscosity and more pronounced elastic properties than pure PLA. Both storage and loss moduli increased with silicate loading at all frequencies and showed nonterminal behavior at low frequencies. The nanocomposites and PLA were then foamed by using the mixture of CO2 and N2 as blowing agent in a batch foaming process. Compared with PLA foam, the nanocomposite foams exhibited reduced cell size and increased cell density at very low organoclay content. With the increase of organoclay content, the cell size was decreased and both cell density and foam density were increased. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 689–698, 2005
Phase transitions in segmented polyesterurethane–DMSO–water systems
Authors: Heijkants R. G. J. C. , Van Calck R. V. , De Groot J. H. , Pennings A. J. , Schouten A. J.
Published: February 2005

The phase separation processes occurring in polyurethane/DMSO/water mixtures were studied using DSC and cloud point measurements. It is demonstrated that liquid–liquid demixing occurs in ternary solutions of segmented polyesterurethanes at sufficiently high water concentrations. It is also shown that the hard segment can crystallize from solution when cooled to room temperature; while if the mixture is cooled to sufficiently low temperatures, DMSO partially freezes, which also induces crystallization of the soft segment. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 716–723, 2005
Thermal transitions and structure of epoxy networks based on α, ω‐diamino terminated poly(propylene oxide)‐block‐poly(ethylene oxide)‐block‐poly(propylene oxide) swollen in water
Authors: Krakovský Ivan , Sánchez Manuel Salmerón
Published: February 2005

Thermal transitions in epoxy networks prepared by reaction of α, ω‐diamino terminated poly(propylene oxide)‐block‐poly(ethylene oxide)‐block‐poly(propylene oxide) and diglycidyl ether of brominated Bisphenol A, swollen in water, were studied by differential scanning calorimetry (DSC) in a broad temperature range (from −100 °C to 20 °C). Networks of two different values of initial molar ratio of amino and epoxy groups were prepared, r (r = 1.00, 2.00), and swollen with different amounts of water up to equilibrium concentration values. The qualitatively different kinds of experimental thermograms have been obtained for two networks and classified according to the amount of water in the sample on the basis of the phase diagram of the system. Also, the concentration dependence of the curves in this diagram (glass transition, melting, and crystallization) as well as the fraction of noncrystallizable water supply some information about the morphology of the system. In this sense, the existence of a microphase separated structure of swollen networks is suggested. The structure consists of hydrophilic and hydrophobic domains and depends on the initial molar ratio of the reactive groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 699–708, 2005
MM/PBSA analysis of molecular dynamics simulations of bovine β‐lactoglobulin: Free energy gradients in conformational transitions?
Authors: Fogolari Federico , Moroni Elisabetta , Wojciechowski Marcin , Baginski Maciej , Ragona Laura , Molinari Henriette
Published: February 2005

The pH‐driven opening and closure of β‐lactoglobulin EF loop, acting as a lid and closing the internal cavity of the protein, has been studied by molecular dynamics (MD) simulations and free energy calculations based on molecular mechanics/Poisson–Boltzmann (PB) solvent‐accessible surface area (MM/PBSA) methodology. The forms above and below the transition pH differ presumably only in the protonation state of residue Glu89. MM/PBSA calculations are able to reproduce qualitatively the thermodynamics of the transition. The analysis of MD simulations using a combination of MM/PBSA methodology and the colony energy approach is able to highlight the driving forces implied in the transition. The analysis suggests that global rearrangements take place before the equilibrium local conformation is reached. This conclusion may bear general relevance to conformational transitions in all lipocalins and proteins in general. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Preservation of cold‐stored guavas influenced by package materials
Authors: Jacomino Angelo Pedro , Bron Ilana Urbano , Sarantópoulos Claire Isabel Grígoli de Luca , Sigrist José Maria Monteiro
Published: February 2005

The objective of this study was to evaluate the influence of package materials on the preservation of cold‐stored ‘Kumagai’ guavas. The treatments were: PO2, co‐extruded polyolephinic film with gas injection (5% O2/5% CO2/N2); PO3, co‐extruded polyolephinic film with gas injection (5% O2/5% CO2/N2); LDPE, linear low density polyethylene film; LDPE‐gas, linear low density polyethylene film with gas injection (3% O2/8% CO2/N2); PVC, polyvinylchloride stretch film; PO1, co‐extruded polyolephinic film and control: non‐packaged guavas. Guavas were stored at 10 ± 1°C/80–90% RH for 21 days, and then transferred to room temperature. Gas composition within the package headspace was analysed during storage and the physical and chemical characteristics of the guavas were evaluated daily during ripening. The modified atmosphere provided by PO1 film was insufficient to promote the benefit of senescence control. Although PVC provided an atmosphere close to that recommended, it did not preserve the colour and pulp firmness. PO2, PO3, LDPE and LDPE‐gas retarded the senescence process of the guavas during 21 days at 10°C plus 2 days at room temperature, but harmed the normal ripening of guavas in some aspects. This can be explained by reduced O2 and elevated CO2 levels within these four packages. None of the packages influenced the titratable acidity and the soluble solids, but they did harm ascorbic acid synthesis. Copyright © 2005 John Wiley & Sons, Ltd.