bluuebunny/crossref_metadata_2025 huggingface dataset:
Library Security in the UK
Authors: Ewing David
Published: July 2002

Focuses on the situation regarding library crime and security as it
appears today in the UK. Discusses common forms of library abuse such as
book theft, non‐return of items, theft of property, staff/user abuse and
vandalism. Examines recent surveys focusing on library crime and looks
at methods of reducing various types of abuse. Concludes that book theft
is extensive, as is non‐return of items. Theft of property has been
widely reported and external vandalism and book mutilation are also
common. However, library counting practices are poor and loss has not
been properly defined. Recommends that inventories be improved and loss
determined precisely in order to improve the accuracy of statistics
collected, making for better evidence on theft; tough legal deterrents
be implemented and that authorities should also develop their own
definite security policies.
Embodied energy analysis of fixtures, fittings and furniture in office buildings
Authors: Treloar Graham J. , McCoubrie Andrew , Love Peter E.D. , Iyer‐Raniga Usha
Published: July 2002

The energy required to operate office buildings has been the focus of much research in the past three decades. There have been limited attempts to quantify the embodied energy consumed in construction. Some embodied energy studies have been relatively detailed. But the energy embodied in fixtures, fittings and furniture which is used by occupiers of buildings is rarely mentioned. The potential significance of the energy embodied in fixtures, fittings and furniture has yet to be established. Aims to establish the likely importance of the energy embodied in fixtures, fittings and furniture relative to other life cycle energy requirements of office buildings in temperate climates. Implementation actions are suggested for the optimisation of the energy embodied in fixtures, fittings and furniture used in buildings. Assists facility managers and businesses with their decision making with respect to the environmental impacts associated with energy use throughout the life cycle of their buildings.
Automatic metric advancing front triangulation over curved surfaces
Authors: Lee C.K.
Published: July 2002

A 3D surface mesh generation scheme is suggested for the triangulation of general bi‐variate surfaces. The target surface to be meshed is represented as a union of bi‐variate sub‐surfaces and hence a wide range of surfaces can be modelled. Different useful features such as repeated curves, crack lines and surface branches are included in the geometrical and topological models to increase the flexibility of the mesh generation scheme. The surface metric tensor specification is employed to define and control the element characteristics in the mesh generation procedure. A robust metric triangulation kernel is used for parametric space mesh generation. The shape qualities of the sub‐surface meshes generated are then improved by using some ad hoc mesh quality enhancement schemes before they are combined together to form the final mesh. Numerical examples indicate that high quality surface meshes with rapid varying element size and stretching characteristics can be generated within a reasonable time limit in a few mesh adaptive iterations.
Work and family expectations of the future managers and professionals of Canada and China
Authors: Bu Nailin , McKeen Carol A.
Published: July 2002

This study investigates the work‐family expectations of the next generation Canadian and Chinese managers and professionals. Three hundred and seventy‐four Canadian and Chinese business students of both sexes were surveyed about their expectations about their own and their spouse’s/partner’s future occupational and family roles. The data revealed that Chinese of both sexes attached greater value to their occupational role and would commit more time to it than Canadians. They also anticipated less difficulty balancing work and family. Men and women in both countries expected traditional gender roles in their future marriages with women performing more household tasks, being less well paid and having less prestigious jobs. Canadian women expected a larger decrease in time for paid work and a larger increase in time for household tasks than Canadian men did during the second five years after graduation, however this sex difference was non‐existent in China.
Intuition‐analysis cognitive style and learning preferences of business and management students
Authors: Sadler‐Smith Eugene
Published: July 2002

The study is an attempt to provide empirical elaboration, in the context of business and management education, for the “onion” and cognitive control models of cognitive style. Using a sample of 226 business and management undergraduates the research explored the relationship between cognitive style (measured using the cognitive style index and learning preference. Using principal components analysis, three categories of learning preference were discerned (active, reflective and individual). Correlational analysis and one way analysis of variance revealed statistically significant relationships between preferences for reflective and individual methods and cognitive style. The results provide some support for the “onion” and cognitive control models; the implications for business and management education, training and development are discussed.
Part of the job: violence in public libraries
Authors: McGrath Hannah , Goulding Anne
Published: July 2002

Discusses some of the issues surrounding violence in the library workplace, analysing violent behaviour in libraries and the various types of “problem users” public library staff may encounter. Discusses the results of a mail survey of public library staff. Staff from four public library authorities were surveyed, to explore the extent to which violent and aggressive behaviour by library users is a recognized problem in public libraries. The results indicate that public libraries suffer from a wide range of “problem users”. Serious incidents which involve physical assault are rare, although verbal abuse is widespread and is generally tolerated by staff who regard it as “part of the job”. Outlines possible preventive measures to reduce the problem and improve the working environment with a particular emphasis on training and customer care initiatives.
Self‐directed learning
Authors: Robotham David
Published: July 2002

The learning style of individuals can be an important consideration
for trainers in looking to optimize the effectiveness of training.
Explores the usefulness of the learning styles approach for trainers.
Considers whether training style should be matched with learning style
within a training programme. Suggests that self‐direction in learning
may be a more appropriate approach in developing skills beyond the
confines of a training programme. Outlines a framework for trainers to
consider in increasing learner self‐direction, and identifies key
factors that should be taken into consideration.
Stakeholder analysis: the implications for the management of HRD
Authors: Garavan Thomas N.
Published: July 2002

Considers some of the issues raised in the previous articles.
Presents a number of guiding principles for HRD management and looks at
a number of structural mechanisms to make a steerer model of stakeholder
management practicable.
Employee commitment in changing organizations: an exploration
Authors: Nijhof Wim J. , de Jong Margriet J. , Beukhof Gijs
Published: July 2002

Commitment of employees can be an important instrument for improving the performance of organizations. Based on international literature and studies, commitment has been defined as organizational and task commitment, and is related to personal, job and organizational characteristics. Intends to explore some important relations between the characteristics of commitment and organizational effects. Between commitment and the level of the organization the most important relations are a better communication and less illness; at the level of the individual employee the commitment to change and to take part very actively in change processes, bringing up new ideas, is important. These conclusions are in line with the literature. Commitment is strongly connected with colleagues and the style of management and could be seen as an important asset of the learning company.
The future of academic libraries: changing formats and changing delivery
Authors: Wood Patricia A. , Walther James H.
Published: July 2002

Time is of the essence for librarians to review the pace of change occurring within higher education and how information will be provided in academic libraries to their vastly changing student population. The integration of technology in higher education has an impact on academic libraries in two direct ways: changing material formats and the scholarly communication options; and changing how information is delivered, beyond the classroom experience. The authors examine the depth of the format change issues, including changes in data preservation and conversion, personnel and facilities issues, and a close examination of scholarly communication and distance education issues facing our higher education and academic libraries.
The chairman’s statement ‐ A content analysis of discretionary narrative disclosures
Authors: Smith Malcolm , Taffler Richard J.
Published: July 2002

Explores whether the firm’s discretionary narrative disclosures measure its financial risk of bankruptcy. Specifically examines the existence of an association between the content of the chairman’s statement and firm failure. Show that these statements are closely associated with financial performance, reinforcing the argument that such unaudited disclosures contain important information. The results have implications both for the form and content of future narrative disclosures by management.
Engineering solder paste performance through controlled stress rheology analysis
Authors: Bao Xiaohua , Lee Ning‐Cheng , Raj Rajkumar B. , Rangan K.P. , Maria Anu
Published: July 2002

The rheology of solder paste significantly affects the qualities of stencil printing, tack and slump performance. This paper describes a series of tests performed on solder paste to investigate and determine the rheological properties of a group of solder pastes and fluxes, and the correlation of those properties with paste performance prior to reflow. Data indicate that: the incidence of print defects are proportional to the material’s compliant qualities (J1 and J2) and are inversely proportional to the elastic properties (G¢/G¢¢ and recovery) and meta‐rigidity (yield stress); slump resistance is proportional to elastic properties (recovery), solid characteristics (stress [G¢ = G¢¢]), and rigidity (|G*|); and that high elastic properties (recovery), low compliance (J1 and J2), and low solid characteristics (stress [G¢ = G¢¢]) are required in order to achieve high tack value. Good correlation between fluxes and solder pastes were observed for yield stress and recovery only, suggesting that those two properties are primarily dictated by fluxes.
Characterization of a solder paste printing process and its optimization
Authors: Poon Gary K.K. , Williams D.J.
Published: July 2002

The objectives of this research are to model the screening process with planned experiments and to identify the optimal setting of the process parameters so as to minimize the printing defects. The percentage volume matching (PVM) and defects per unit (DPU) are the two quality characteristics of interest. A fractional factorial design was employed to study simultaneously the effects of eight process factors on the PVM and DPU and their possible interactions. Subsequent analysis shows that a low level of the stencil cleaning interval and low temperature results in the minimum DPU while maintaining a PVM very close to 100 per cent. Empirical relationships between these two quality characteristics and the important factors were formulated using regression analysis and close matches were found during subsequent validation experiments.
Obstacles to foreign direct investment in Russia
Authors: Jones Alan , Fallon Grahame , Golov Roman
Published: July 2002

Explores the obstacles facing trans‐national corporations (TNC) considering FDI in Russia. Dunning (1994) suggests that countries’ abilities to attract and exploit the potential economic benefits of inbound FDI vary according to their national political, economic and legal cultures, traditions and infrastructures, together with the economic objectives and policies pursued by host governments. This paper seeks to make use of Dunning’s model, in exploring the obstacles to FDI in modern Russia, and their implications for TNCs. The papers’ findings suggest that Russia’s relative lack of success in attracting FDI and exploiting its potential benefits during the 1990s can be attributed to her national infrastructural factors and government policies, as Dunning’s model suggests. Russia’s ability to attract a larger share of FDI in future seems likely to be constrained by national ambivalence towards the benefits of FDI, together with the political and economic realities of her current situation.
Using the compression properties of pillows to estimate sleeping comfort
Authors: Yokura Hiroko , Nakanishi Masae , Niwa Masako
Published: July 2002

In order to establish an objective method of evaluating pillow comfort, we investigate the relation between the sensory evaluation of pillows and the compression properties of pillows. The subjective evaluation values of hardness, fitness and total comfort were correlated with the compression energy WC and the displacement Δ T at the maximum load of 50gf/cm2. Pillows which have large values of WC and Δ T were regarded as softer, fitter and more comfortable. Pillows estimated as being soft and fit showed larger contact areas and less contact pressure on the head. For the pillows which have the same flat shape, a good agreement between the individual judges was shown in the assessments of hardness and height. The shape and packing density of polyethylene pipes affected the degree of the hardness of the pillows.
Appraisal – The impact of increased control on the “state of play” in New Zealand schools
Authors: Piggot‐Irvine Eileen
Published: July 2002

Increased control has been linked with increased defensiveness, decreased internal commitment, inconsistent adoption of initiatives, and mixed reception. In New Zealand we have seen an incremental tightening of control in the appraisal (evaluation) context with progressively enhanced requirements for accountability in the post‐reform (post‐1989) period in schools. Reports on the context of this tightening of accountability, or increased control, and presents evidence to demonstrate its impact. The evidence was provided via the results of a four‐year (1996‐1999) longitudinal questionnaire study from the period prior to the introduction of the 1996 Draft National Guidelines for Performance Management in Schools (DNGPMS), through to that of prescribed performance criteria (professional standards) for teachers and managers in schools in 1998 and 1999. The results contradict the predicted negative impacts and provide evidence that by 1999 there was a developing positive impact from the tightening of accountability in appraisal. The conclusion discusses recent threats to the positive gains reported in this study.
Principals’ efficacy beliefs about teacher evaluation
Authors: Painter Suzanne R.
Published: July 2002

School principals have been criticized for their inaction in dealing with incompetent or low‐performing teachers. Bandura’s self‐efficacy theory suggests that principals’ beliefs in their own efficacy regarding the tasks of the evaluation may affect their motivation to perform the tasks of supervision. This survey of elementary and middle school principals suggests that principals place high value on the task of evaluating low‐performing teachers and believe that they are well equipped to do so. The data also suggest that the principals believe that they are adequately addressing the problems of poor performance, suggesting a need for research to determine why principals do not share perceptions of unapprised incompetence.
Professional mentorship for women educators in government schools
Authors: Catherine Ehrich Lisa
Published: July 2002

Discusses the use and development of mentorship as a policy
mechanism designed to promote the career development and advancement of
women in the context of educational administration in government schools
in Australia. The reason mentorship is the particular factor which has
been identified to assist women educators′ careers here is that over the
last decade there has been a general consensus by researchers in both
academic and managerial circles that mentorship is a significant career
tool, and a prerequisite for career success for both males and females.
Access to a mentor, an older and more experienced career professional
who is able to use his or her influence and power in assisting a young
and up‐and‐coming protégé, has been closely associated
with career advancement. Because women experience difficulties in
securing traditional mentoring relationships, it is argued here that a
mentorship policy will positively influence the career prospects of
women educators by enabling them to be part of the power structures in
educational administration.
Understanding principals’ attitudes towards inclusive schooling
Authors: Bailey Jeff , du Plessis Diana
Published: July 2002

Reports that including students with disabilities in regular schools is a movement which is attracting considerable community support. Inclusion is both a philosophy based on social justice, and a practice requiring, in many cases, significant adaptations by the school community. Suggests that, as school principals have a significant role in implementing policies in schools, to be able to predict their approach to inclusion, it is important to understand their attitudes towards inclusion. Reports on qualitative data on the attitudes towards inclusion of more than 200 school principals in Queensland schools. Although the majority are supportive of inclusion, their responses suggest they are “qualified” inclusionists. Concludes that, while responding to the social justice imperatives and recognizing the rights of students with disabilities, the principals were also concerned about the resource implications which attend the implementation of inclusion.
Feminist educational leadership in a New Zealand neo‐liberal context
Authors: Strachan Jane
Published: July 2002

A qualitative, feminist, case study methodology was used to research the feminist leadership of three women principals of coeducational secondary schools. Information was collected by interviewing and observing the three feminist principals, interviewing 24 staff, and collecting documents. Research indicated that being student focused was central to the practice of feminist educational leaders. This thesis explored how they were able to remain student focused in a New Zealand, neo‐liberal, education context with increased financial, accountability and marketing responsibilities. By resisting and appropriating the opportunities and demands created by the reforms, the feminist principals were, to some extent, able to resist the pressure to be less student focused. However, in doing so they worked very long hours. Their personal value systems and the school context were also important influences on their practice. There were both commonalities and diversity among the women’s leadership.
Disaster stress: an emergency management perspective
Authors: Paton Douglas , Flin Rhona
Published: July 2002

This paper examines the sources of stress likely to be encountered by emergency managers when responding to a disaster. Stressors relating to environmental (e.g. time pressure, level of risk, heat), organisational (e.g. bureaucracy, appropriateness of information, decision support and management systems) and operational (e.g. incident command, decision making, interagency liaison, team and media management) demands are considered. The mediating role of personality and transient states of physical (e.g. fitness and fatigue) and psychological (e.g. high levels of occupational stress) states are reviewed in terms of their influence on stress, judgement and decision making. Strategies for identifying which of these potential stress factors can be controlled or reduced and for training emergency managers to deal with the others are discussed.
Use of query reformulation and relevance feedback by Excite users
Authors: Spink Amanda , Jansen Bernard J. , Cenk Ozmultu H.
Published: July 2002

Examines the use of query reformulation, and particularly the use of relevance feedback by users of the Excite Web search engine. A total of 985 user search sessions from a data set of 18,113 user search sessions containing 51,473 queries were examined. Includes a qualitative and quantitative analysis of 191 user sessions including more than one query, to examine patterns of user query reformulation; and second, all 804 user sessions including relevance feedback were examined. Results show limited use of query reformulation and relevance feedback by Excite users – only one in five users reformulated queries. Most relevance feedback sessions were successful. Identifies the most common pattern of searching and discusses implications for Web search system design.
Conversion of RP models to investment castings
Authors: Dickens P.M. , Stangroom R. , Greul M. , Holmer B. , Hon K.K.B. , Hovtun R. , Neumann R. , Noeken S. , Wimpenny D.
Published: July 2002

The Tooling and Casting subgroup of the European Action on Rapid Prototyping (EARP) has undertaken a project to investigate the problems associated with using rapid prototype models as sacrificial patterns for investment casting. The accuracy and surface finish of the models and the castings were also assessed so that a comparison could be made. Models from each process were manufactured by different members of EARP and then three foundries were each given a set of models to convert to castings. Observes that one of the oldest metal manufacturing techniques, which dates back to 4000‐6000 BC, is being used with one of the most modern ‐ rapid prototyping.
Thermodynamic propensities of amino acids in the native state ensemble: Implications for fold recognition
Authors: Wrabl James O. , Larson Scott A. , Hilser Vincent J.
Published: July 2002

An amino acid sequence, in the context of the solvent environment, contains all of the thermodynamic information necessary to encode a three‐dimensional protein structure. To investigate the relationship between an amino acid sequence and its corresponding protein fold, a database of thermodynamic stability information was assembled that spanned 2951 residues from 44 nonhomologous proteins. This information was obtained using the COREX algorithm, which computes an ensemble‐based description of the native state of a protein. It was observed that amino acid types partitioned unequally into high, medium, and low thermodynamic stability environments. Furthermore, these distributions were reproducible and were significantly different than those expected from random partitioning. To assess the structural importance of the distributions, simple fold‐recognition experiments were performed based on a 3D‐1D scoring matrix containing only COREX residue stability information. This procedure was able to recover amino acid sequences corresponding to correct target structures more effectively than scoring matrices derived from randomized data. High‐scoring sequences were often aligned correctly with their corresponding target profiles, suggesting that calculated thermodynamic stability profiles have the potential to encode sequence information. As a control, identical fold‐recognition experiments were performed on the same database of proteins using DSSP secondary structure information in the scoring matrix, instead of COREX residue stability information. The comparable performance of both approaches suggested that COREX residue stability information and secondary structure information could be of equivalent utility in more sophisticated fold‐recognition techniques. The results of this work are a consequence of the idea that amino acid sequences fold not into single, rigidly stable structures but rather into thermodynamic ensembles best represented by a time‐averaged structure.
Fold recognition without folds
Authors: Koretke Kristin K. , Russell Robert B. , Lupas Andrei N.
Published: July 2002

Fold recognition predicts protein three‐dimensional structure by establishing relationships between a protein sequence and known protein structures. Most methods explicitly use information derived from the secondary and tertiary structure of the templates. Here we show that rigorous application of a sequence search method (PSI‐BLAST) with no reference to secondary or tertiary structure information is able to perform as well as traditional fold recognition methods. Since the method, SENSER, does not require knowledge of the three‐dimensional structure, it can be used to infer relationships that are not tractable by methods dependent on structural templates.
An improved hydrogen bond potential: Impact on medium resolution protein structures
Authors: Fabiola Felcy , Bertram Richard , Korostelev Andrei , Chapman Michael S.
Published: July 2002

A new semi‐empirical force field has been developed to describe hydrogen‐bonding interactions with a directional component. The hydrogen bond potential supports two alternative target angles, motivated by the observation that carbonyl hydrogen bond acceptor angles have a bimodal distribution. It has been implemented as a module for a macromolecular refinement package to be combined with other force field terms in the stereochemically restrained refinement of macromolecules. The parameters for the hydrogen bond potential were optimized to best fit crystallographic data from a number of protein structures. Refinement of medium‐resolution structures with this additional restraint leads to improved structure, reducing both the free R‐factor and over‐fitting. However, the improvement is seen only when stringent hydrogen bond selection criteria are used. These findings highlight common misconceptions about hydrogen bonding in proteins, and provide explanations for why the explicit hydrogen bonding terms of some popular force field sets are often best switched off.
The HoxB1 hexapeptide is a prefolded domain: Implications for the Pbx1/Hox interaction
Authors: Slupsky Carolyn M. , Sykes David B. , Gay Grant L. , Sykes Brian D.
Published: July 2002

Hox proteins are transcriptional regulators that bind consensus DNA sequences. The DNA‐binding specificity of many of these Hox proteins is modulated by the heterodimerization with partners, such as the Pbx proteins. This cooperative heterodimerization is accomplished through a conserved hexapeptide motif found N‐terminal to the Hox DNA‐binding homeodomain. Several human leukemias have been associated with a chromosomal translocation involving either the Hox gene (i.e., NUP98/HOXA9) or the gene encoding Pbx1 (E2A/PBX1). The transforming ability of these fusion oncoproteins relies at least partially on the ability to interact with one another through this hexapeptide motif. Herein we describe NMR structural calculations of the hexapeptide of HoxB1 (Nα‐acetyl‐Thr‐Phe‐Asp‐Trp‐Met‐Lys‐amide) that has been shown to mediate binding between HoxB1 and Pbx1 and a hexapeptide consensus sequence (Nα‐acetyl‐Leu‐Phe‐Pro‐Trp‐Met‐Arg‐amide). The consensus peptide exists in two conformations caused by cis–trans isomerization of the Phe–Pro peptide bond. The structures of the HoxB1 peptide and the trans form of the consensus peptide reveal a turn very similar to that found as part of the HoxB1/Pbx1/DNA complex in the X‐ray crystal structure. This observation implies that this region is at least partially ‘preformed’ and thus ready to interact with Pbx1 and stabilize binding of Pbx1 and HoxB1 to DNA. The structural results presented here provide a starting point for synthesizing potential nonpeptide or cyclical peptide antagonists that mimic the interaction of these transcriptional cofactors resulting in a potential chemotherapeutic for certain types of leukemias.
Tubular system volume changes in twitch fibres from toad and rat skeletal muscle assessed by confocal microscopy
Authors: Launikonis Bradley S. , Stephenson D. George
Published: July 2002

The volume of the extracellular compartment (tubular system) within intact muscle fibres from cane toad and rat was measured under various conditions using confocal microscopy. Under physiological conditions at rest, the fractional volume of the tubular system (t‐sysVol) was 1.38 ± 0.09 % (n = 17), 1.41 ± 0.09 % (n = 12) and 0.83 ± 0.07 % (n = 12) of the total fibre volume in the twitch fibres from toad iliofibularis muscle, rat extensor digitorum longus muscle and rat soleus muscle, respectively. In toad muscle fibres, the t‐sysVol decreased by 30 % when the tubular system was fully depolarized and decreased by 15 % when membrane cholesterol was depleted from the tubular system with methyl‐β‐cyclodextrin but did not change as the sarcomere length was changed from 1.93 to 3.30 μm. There was also an increase by 30 % and a decrease by 25 % in t‐sysVol when toad fibres were equilibrated in solutions that were 2.5‐fold hypertonic and 50 % hypotonic, respectively. When the changes in total fibre volume were taken into consideration, the t‐sysVol expressed as a percentage of the isotonic fibre volume did actually decrease as tonicity increased, revealing that the tubular system in intact fibres cannot be compressed below 0.9 % of the isotonic fibre volume. The results can be explained in terms of forces acting at the level of the tubular wall. These observations have important physiological implications showing that the tubular system is a dynamic membrane structure capable of changing its volume in response to the membrane potential, cholesterol depletion and osmotic stress but not when the sarcomere length is changed in resting muscle.
Intrinsic physiological properties of cat retinal ganglion cells
Authors: O'Brien Brendan J. , Isayama Tomoki , Richardson Randal , Berson David M.
Published: July 2002

Retinal ganglion cells (RGCs) are the output neurons of the retina, sending their signals via the optic nerve to many different targets in the thalamus and brainstem. These cells are divisible into more than a dozen types, differing in receptive field properties and morphology. Light responses of individual RGCs are in large part determined by the exact nature of the retinal synaptic network in which they participate. Synaptic inputs, however, are greatly influenced by the intrinsic membrane properties of each cell. While it has been demonstrated clearly that RGCs vary in their intrinsic properties, it remains unclear whether this variation is systematically related to RGC type. To learn whether membrane properties contribute to the functional differentiation of RGC types, we made whole‐cell current clamp recordings of RGC responses to injected current of identified cat RGCs. The data collected demonstrated that RGC types clearly differed from one another in their intrinsic properties. One of the most striking differences we observed was that individual cell types had membrane time constants that varied widely from approximately 4 ms (alpha cells) to more than 80 ms (zeta cells). Perhaps not surprisingly, we also observed that RGCs varied greatly in their maximum spike frequencies (kappa cells 48 Hz‐alpha cells 262 Hz) and sustained spike frequencies (kappa cells 23 Hz‐alpha cells 67 Hz). Interestingly, however, most RGC types exhibited similar amounts of spike frequency adaptation. Finally, RGC types also differed in their responses to injection of hyperpolarizing current. Most cell types exhibited anomalous rectification in response to sufficiently strong hyperpolarization, although alpha and beta RGCs showed only minimal, if any, rectification under similar conditions. The differences we observed in RGC intrinsic properties were striking and robust. Such differences are certain to affect how each type responds to synaptic input and may help tune each cell type appropriately for their individual roles in visual processing.
Roscovitine: a novel regulator of P/Q‐type calcium channels and transmitter release in central neurons
Authors: Yan Zhen , Chi Ping , A. Bibb James , A. Ryan Timothy , Greengard Paul
Published: July 2002

Roscovitine is widely used for inhibition of cdk5, a cyclin‐dependent kinase expressed predominantly in the brain. A novel function of roscovitine, i.e. an effect on Ca2+ channels and transmitter release in central neurons, was studied by whole‐cell voltage‐clamp recordings and time‐lapse fluorescence imaging techniques. Extracellular application of roscovitine markedly enhanced the tail calcium current following repolarization from depolarized voltages. This effect was rapid, reversible and dose dependent. Roscovitine dramatically slowed the deactivation kinetics of calcium channels. The deactivation time constant was increased 3‐ to 6‐fold, suggesting that roscovitine could prolong the channel open state and increase the calcium influx. The potentiation of tail calcium currents caused by roscovitine and by the L‐channel activator Bay K 8644 was not occluded but additive. Roscovitine‐induced potentiation of tail calcium currents was significantly blocked by the P/Q‐channel blocker CgTx‐MVIIC, indicating that the major target of roscovitine is the P/Q‐type calcium channel. In mutant mice with targeted deletion of p35, a neuronal specific activator of cdk5, roscovitine regulated calcium currents in a manner similar to that observed in wild‐type mice. Moreover, intracellular perfusion of roscovitine failed to modulate calcium currents. These results suggest that roscovitine acts on extracellular site(s) of calcium channels via a cdk5‐independent mechanism. Roscovitine potentiated glutamate release at presynaptic terminals of cultured hippocampal neurons detected with the vesicle trafficking dye FM1–43, consistent with the positive effect of roscovitine on the P/Q‐type calcium channel, the major mediator of action potential‐evoked transmitter release in the mammalian CNS.
Sodium current modulation by a tubulin/GTP coupled process in rat neonatal cardiac myocytes
Authors: Motlagh Delara , Alden Kris J. , Russell Brenda , García Jesús
Published: July 2002

Microtubule disassembly by colchicine increases spontaneous beating of neonatal cardiac myocytes by an unknown mechanism. Here, we measure drug effects on spontaneous calcium transients and whole cell ionic currents to define the route between microtubule depolymerization and the increase in the rate of contraction. Colchicine treatment disassembles microtubules resulting in free tubulin dimers, thereby increasing the spontaneous beating frequency and changing both the rates of rise and decay of calcium transients. In addition, colchicine treatment produces an increase of the sodium current (INa) while ICa is not modified. The colchicine‐enhanced INa was blocked by the addition of 10 μm TTX. In addition, the colchicine‐induced increase of INa was prevented when GTP was omitted from the patch pipette. Vinblastine also depolymerizes microtubules but re‐aggregates tubulin into paracrystalline structures. Free tubulin dimers are not increased with vinblastine treatment. We found no modification in calcium transients or INa in the presence of vinblastine. Action potential durations measured at 50 % and 90 % repolarization were shorter, and the dV/dt was larger, in colchicine‐treated cells compared to untreated cells. The resting membrane potential and overshoot of the action potentials were comparable in both kinds of cells. Our data suggest that release of free tubulin dimers may activate G proteins, which in turn modulate the sodium channel. An increase in whole cell INa changes the spontaneous firing rate and this may be the underlying cause of the increase in the frequency of contraction in neonatal cardiac myocytes. We suggest a new role for dimeric tubulin in regulating membrane excitability.
Intramuscular fatty acid metabolism in contracting and non‐contracting human skeletal muscle
Authors: Sacchetti M. , Saltin B. , Osada T. , van Hall G.
Published: July 2002

The present study was undertaken to investigate the fate of blood‐borne non‐esterified fatty acids (NEFA) entering contracting and non‐contracting knee extensor muscles of healthy young individuals. [U‐13C]‐palmitate was infused into a forearm vein during 5 h of one‐legged knee extensor exercise at 40 % of maximal work capacity and the NEFA kinetics, oxidation and rate of incorporation into intramuscular triacylglycerol (mTAG) were determined for the exercising and the non‐exercising legs. During 4 h of one‐legged knee extensor exercise, mtag content decreased by 30 % (P < 0.05) in the contracting muscle, whereas it was unchanged in the non‐contracting muscle. The uptake of plasma NEFA, as well as the proportion directed towards oxidation, was higher in the exercising compared to the non‐exercising leg, whereas the rate of palmitate incorporation into mtag was fourfold lower (0.70 ± 0.14 vs. 0.17 ± 0.04 μmol (g dry wt)−1 h−1; P lt; 0.05), resulting in fractional synthesis rates of 1.0 ± 0.2 and 3.8 ± 0.9 % h−1 (P lt; 0.01) for the contracting and non‐contracting muscle, respectively. These findings demonstrate that mTAG in human skeletal muscle is continuously synthesised and degraded and that the metabolic fate of plasma NEFA entering the muscle is influenced by muscle contraction, so that a higher proportion is directed towards oxidation at the expense of storage in mTAG.
Stress Analysis of Thermal Inclusions With Interior Voids and Cracks
Authors: Ru C. Q.
Published: July 2002

Thermal mismatch induced residual stresses are identified as one of the major causes of voiding and failure of some critical components in electronic packaging, such as passivated interconnect lines and isolation trenches. In this paper, a general method is presented for thermal stress analysis of an embedded structural element in the presence of internal or nearby voids and cracks. Here, the elastic mismatch between dissimilar materials is ignored. Hence, the embedded structural element is modeled as a thermal inclusion of arbitrary shape surrounded by an infinite elastic medium of the same elastic constants. Thermal stresses are caused by thermal mismatch between the inclusion and the surrounding material due to a uniform change in temperature. With the present method, the problem is reduced to one of an infinite homogeneous medium containing the same voids and cracks, subjected to a set of remote stresses determined by the geometrical shape of the thermal inclusion. In particular, the remote stresses are uniform when the thermal inclusion is an ellipse. The method gives an elementary expression for the internal stress field of a thermal inclusion with a single interior void or crack. Several examples of practical interest are used to illustrate the method. The results show that an internal void or crack can significantly change stress distribution within the inclusion and gives rise to stress concentration around the void or crack. [S1043-7398(00)00303-0]
CBGA Solder Joint Reliability Evaluation Based on Elastic-Plastic-Creep Analysis
Authors: Pang John H. L. , Seetoh C. W. , Wang Z. P.
Published: July 2002

Three-dimensional nonlinear finite element analysis of a ceramic ball grid array (CBGA) package was conducted to determine the solder joint creep and plastic strain deformations in a simulated thermal cycling loading. Two methods of analysis were carried out to model the creep deformations during the dwell and during the temperature ramps in the thermal cycling loading. The equivalent plastic and creep strains are presented for the two analysis method to demonstrate the differences in the strain components. Both creep and plastic strain fatigue life prediction models were used to estimate the thermal cycling life of CBGA solder joints subjected to accelerated thermal cycling tests. The lives predicted using this nonlinear finite element analysis results were satisfactory and conservative compared to the experimental test results. [S1043-7398(00)01103-8]
Laminar Natural Convection in Isosceles Triangular Enclosures Heated From Below and Symmetrically Cooled From Above
Authors: Holtzman G. A. , Hill R. W. , Ball K. S.
Published: July 2002

A numerical study of natural convection in an isosceles triangular enclosure with a heated horizontal base and cooled upper walls is presented. Nearly every previous study conducted on this subject to date has assumed that the geometric plane of symmetry is also a plane of symmetry for the flow. This problem is re-examined over aspect ratios ranging from 0.2 to 1.0 and Grashof numbers from 103 to 105. It is found that a pitchfork bifurcation occurs at a critical Grashof number for each of the aspect ratios considered, above which the symmetric solutions are unstable to finite perturbations and asymmetric solutions are instead obtained. Results are presented detailing the occurrence of the pitchfork bifurcation in each of the aspect ratios considered, and the resulting flow patterns are described. A flow visualization study is used to validate the numerical observations. Computed local and mean heat transfer coefficients are also presented and compared with results obtained when flow symmetry is assumed. Differences in local values of the Nusselt number between asymmetric and symmetric solutions are found to be more than 500 percent due to the shifting of the buoyancy-driven cells. [S0022-1481(00)02503-2]
Experimental Evaluation of EHD Film Shape and Its Comparison With Numerical Solution
Authors: Krˇupka I. , Hartl M. , Polisˇcˇuk R. , Cˇerma´k J. , Lisˇka M.
Published: July 2002

Colorimetric interferomentry has been applied to the study of EHD lubrication of point contacts under pure rolling conditions to obtain lubricant film shapes with high accuracy and resolution. An RGB CCD camera together with an extensive image processing software has enabled real time evaluation of chromatic interferograms. The classical numerical isothermal solution of EHD lubrication of point contacts has been used for the comparison with three-dimensional representations of film thickness distributions obtained from experiments. A good agreement was found between experimental and numerical EHD film shapes by comparing lubricant film profiles and positions of minimum film thickness. Both experimental results and numerical solution confirm the ratio between central and minimum film thickness to change significantly with operating conditions. [S0742-4787(00)00404-5]
Nonlinear Theory of Tear Film Rupture
Authors: Gorla Madhu Sudan Reddy , Gorla Rama Subba Reddy
Published: July 2002

Nonlinear thin film rupture has been analyzed by investigating the stability of tear films to finite amplitude disturbances. The dynamics of the liquid film is formulated using the Navier–Stokes equations, including a body force term due to van der Waals attractions. The governing equation was solved by the finite difference method as part of an initial value problem for spatial periodic boundary conditions. The rupture of the tear film covering the cornea and the formation of dry spots is an important phenomenon in various pathological states associated with a dry eye. [S0148-0731(00)00605-1]
Anomalous Moisture Diffusion in Viscoelastic Polymers: Modeling and Testing
Authors: Roy S. , Xu W. X. , Park S. J. , Liechti K. M.
Published: July 2002

It is now well known that Fick’s Law is frequently inadequate for describing moisture diffusion in polymers or polymer composites. Non-Fickian or anomalous diffusion typically occurs when the rates of diffusion and viscoelastic relaxation in a polymer are comparable, and the ambient temperature is below the glass transition temperature Tg of the polymer. As a result, it is necessary to take into account the time-dependent response of a polymer, analogous to viscoelastic relaxation of mechanical properties, in constructing such a model. In this paper, a simple yet robust methodology is proposed that would allow characterization of non-Fickian diffusion coefficients from moisture weight gain data for a polymer below its Tg. Subsequently, these diffusion coefficients are used for predicting moisture concentration profiles through the thickness of a polymer. Moisture weight gain data at different temperatures for an epoxy adhesive is employed to calibrate the model. Specimen thickness independence of the modeling parameters is established through comparison with test data. A finite element procedure that extends this methodology to more complex shapes and boundary conditions is also validated. [S0021-8936(00)02402-8]
An Analytical Study of the Effect of the Contact Ratio on the Spur Gear Dynamic Response
Authors: Andersson Anette
Published: July 2002

A model was used, where the total gear mesh stiffness was approximated by two constant stiffness levels, in order to analyze the influence of the contact ratio on the dynamic response of spur gears. Due to the stiffness variation there is parametric excitation of the transmission error, which generally causes tooth separation at certain critical rotational speeds. The present paper discloses a method to analytically calculate which contact ratio to use in order to avoid tooth separation near a specific critical rotational speed. [S1050-0472(00)02604-0]
A Metric for Evaluating Design Commonality in Product Families
Authors: Kota Sridhar , Sethuraman Kannan , Miller Raymond
Published: July 2002

Many companies develop a market strategy built around a family of products. These companies regularly add new product variations to the family in order to meet changing market needs or to attract a broader customer base. Although the core functionality remains essentially unchanged across the products within a family, new functions, feature combinations and technologies are incorporated into each new product. If allowed to grow unchecked, these component variations, commonly referred to as “complexity”, can result in a loss of productivity or quality. The challenge lies in an effective management of product variations in the design studio and on the manufacturing floor. The key is to minimize non-value added variations across models within a product family without limiting customer choices. In this paper we discuss the factors that contribute to product complexity in general, and present an objective measure, called the Product Line Commonality Index, to capture the level of component commonality in a product family. Through our Walkman case study, we present a simple yet powerful method of benchmarking product families1. This method gauges the family’s ability to share parts effectively (modularity) and to reduce the total number of parts (multi-functionality). [S1050-0472(00)02704-5]
The Fiber Composite With Nonlinear Interface—Part I: Axial Tension
Authors: Levy A. J.
Published: July 2002

This paper treats the effective axial tension response of a composite consisting of fibers that debond from the matrix according to nonlinear Needleman-type cohesive zones. A second, related paper (Part II) treats effective antiplane shear response. The composite cylinders representation of a representative volume element (RVE) is employed throughout. For axial tension loading a simple rotationally symmetric boundary value problem for a single composite cylinder is solved. Bounds on the total potential energy and the total complementary energy are shown to coincide and an exact solution for axial extension and Poisson contraction of an RVE of the composite is obtained. Nonlinear interfacial debonding, however, is shown to have a negligible effect on extensional response and only a small, though potentially destabilizing, effect on Poisson contraction response. [S0021-8936(00)02004-3]