bluuebunny/crossref_metadata_2025 huggingface dataset:
A multivariate study of moss distributions in relation to environment in the Gulf of St. Lawrence region, Canada
Authors: Belland René J
Published: March 2005

Moss distribution patterns in the Gulf of St. Lawrence were investigated using multivariate analyses to determine the relationship of the patterns to environmental factors. Distance-based redundancy analysis was used to ordinate 29 operational geographical units (OGU) or sampling units based on their moss floras, and hierarchical cluster analysis in combination with indicator analysis was used to produce classifications of both species and sampling units. Climatic variables, in particular, warmth of the growing season, were the most important factors determining species distribution; this resulted in a northsouth gradient through the study area. Oceanity was also shown to be important and manifested as an eastwest gradient. Edaphic factors, in particular, amount of calcareous rock outcrop, had a secondary influence and modified the patterns established by climate. Ordination of OGUs showed the effects of environment to be more variable in the northern half of the Gulf of St. Lawrence, which may in part explain the higher species richness there. Seven OGU groups were recognized based on cluster analysis of floristic composition. Although indicator species were few, most groups were distinguished by unique sets of regionally rare species. Eleven species elements were identified based on species occurrence in OGUs. The elements constituted sets of overlapping distributions showing southern, northern, and eastern biases in the Gulf region. Multivariate analysis was shown to be effective tool for extracting mossenvironment patterns, even at medium geographic scale.Key words: Gulf of St. Lawrence, mosses, environment, richness, distribution, ordination, cluster analysis.
Cosmogenic exposure dating in arctic glacial landscapes: implications for the glacial history of northeastern Baffin Island, Arctic Canada
Authors: Briner Jason P , Miller Gifford H , Davis P Thompson , Finkel Robert C
Published: March 2005

Cosmogenic exposure dating and detailed glacial-terrain mapping from the Clyde Foreland, Baffin Island, Arctic Canada, reveal new information about the extent and dynamics of the northeastern sector of the Laurentide Ice Sheet (LIS) during the last glacial maximum (LGM). The Clyde Foreland is composed of two distinct landscape zones: (1) glacially scoured terrain proximal to the major sources of Laurentide ice that flowed onto the foreland, and (2) ice distal unscoured sectors of the foreland. Both zones are draped with erratics and dissected by meltwater channels, indicating past ice cover. We interpret the two landscape classes in terms of ice sheet erosive ability linked with basal thermal regime: glacially scoured terrain was occupied by erosive warm-based ice, and unscoured terrain was last occupied by non-erosive cold-based ice. Cosmogenic exposure ages from >100 erratics from the two landscape types have different age distributions. Cosmogenic exposure ages from the glacially scoured areas suggest ice cover during the LGM, followed by deglaciation between ~15 and ~12 ka. In the unscoured lowlands, the cosmogenic exposure ages have multiple modes ranging between ~12 and ~50 ka, suggesting multiple periods of cold-based ice cover during the last glacial cycle. In landscapes covered by cold-based ice, large numbers of cosmogenic exposure ages are required for elucidating glacial histories.
Natural chemical markers identify source and date of introduction of an exotic species: lake trout (Salvelinus namaycush) in Yellowstone Lake
Authors: Munro Andrew R , McMahon Thomas E , Ruzycki James R
Published: March 2005

Exotic species invasions pose a pervasive threat to aquatic ecosystems worldwide, yet fundamental questions about the geographic origin and timing of invasions or introductions are frequently difficult to answer. We used natural chemical markers (Sr:Ca ratios) in otoliths to identify probable source and date of introduction of exotic lake trout (Salvelinus namaycush) into Yellowstone Lake, Wyoming, USA. Otolith Sr:Ca ratios were significantly different among lake trout known to have reared in three different Yellowstone National Park lakes (Yellowstone, Heart, and Lewis lakes) and showed little variation along the otolith axis, indicating that lake trout within each lake experienced a similar, and consistent, environmental history. In contrast, suspected transplants showed a large and rapid increase in otolith Sr:Ca ratios indicative of a marked shift to water of differing chemistry. Timing of the abrupt change in Sr:Ca ratios indicated that some lake trout were introduced into Yellowstone Lake during the late 1980s, but more recent transplants also occurred. A discriminant model identified Lewis Lake as the likely source lake for lake trout transplanted into Yellowstone Lake. Our results demonstrate that chemical signatures within otoliths can serve as an important forensic tool for identifying the probable source and date of exotic fish introductions.
Biogeochemistry of persistent bioaccumulative toxicants: processes affecting the transport of contaminants to remote areas
Authors: Blais J M
Published: March 2005

We release a very wide variety of synthetic chemicals to the environment. The persistence, environmental behavior, and toxicity of these chemicals will determine the severity of their impacts on our ecosystems. In some cases, contaminated areas are far from the source of pollution. The study of contaminants in remote environments, however, provides important information about a chemical's environmental behavior. For example, when anthropogenic chemicals are recorded in very remote arctic environments, we know that these chemicals arrived by long-range transport. When we examine contaminants on a global scale, we observe a global distribution that is not random, but rather represents a systematic geochemical behavior that is affected by atmospheric and ocean transport, deposition from the atmosphere, and concentration in food chains. This paper reviews the nature and processes involved in long-range transport of chemicals to remote environments and explores some of the pathways taken by persistent bioaccumulative toxicants following their release.
Laminar fully developed flow and heat transfer of RobertsonStiff fluids in a rectangular duct
Authors: Sayed-Ahmed M E , El-Yazal A S
Published: March 2005

The laminar fully developed flow and heat transfer through a rectangular duct of a viscous incompressible RobertsonStiff fluid is investigated. RobertsonStiff fluids are time independent non-Newtonian materials possessing a yield value. The governing momentum and energy equations are solved numerically using finite-difference approximations. We consider two cases of thermal boundary conditions: H1 the "circumferentially constant wall temperature and axially constant wall heat flux" and H2 the "circumferentially and axially constant wall heat flux". The velocity, temperature, the average friction factor and Nusselt numbers for the two cases are computed for various values of the physical parameters. The present results have been compared with the known solutions for Newtonian and power-law fluids and are found to be in good agreement.PACS Nos.: 47.50.+d, 47.15.x
Not-so-classical mechanics: unexpected symmetries of classical motion
Authors: Wheeler James T
Published: March 2005

A survey of topics of recent interest in Hamiltonian and Lagrangian dynamical systems, including accessible discussions of regularization of the central-force problem; inequivalent Lagrangians and Hamiltonians; constants of central-force motion; a general discussion of higher order Lagrangians and Hamiltonians, with examples from Bohmian quantum mechanics, the Kortewegde Vries equation, and the logistic equation; gauge theories of Newtonian mechanics; and classical spin, Grassmann numbers, and pseudomechanics. PACS No.: 45.25.Jj
Transient Disruption of Ventrolateral Prefrontal Cortex During Verbal Encoding Affects Subsequent Memory Performance
Authors: Kahn Itamar , Pascual-Leone Alvaro , Theoret Hugo , Fregni Felipe , Clark Dav , Wagner Anthony D.
Published: March 2005

Episodic memory supports conscious remembrance of everyday experience. Prior functional neuroimaging data indicate that episodic encoding during phonological task performance is correlated with activation in bilateral posterior ventrolateral prefrontal cortex (pVLPFC), although uncertainty remains regarding whether these prefrontal regions make necessary contributions to episodic memory formation. Using functional MRI data to guide application of single-pulse transcranial magnetic stimulation (spTMS), this study examined the necessity of left and right pVLPFC for episodic encoding (as expressed through subsequent memory performance). To assess the timing of critical computations, pVLPFC function was transiently disrupted at different poststimulus onset times while subjects made syllable decisions about visually presented familiar and unfamiliar words; subsequent memory for these stimuli was measured. Results revealed that left pVLPFC disruption during encoding of familiar words impaired subsequent memory, expressed as a decline in recognition confidence, with disruption being maximal at 380 ms after stimulus onset. In contrast, right pVLPFC disruption facilitated subsequent memory for familiar words, expressed as an increase in medium confidence recognition, with this facilitation being maximal at 380 ms. Finally, phonological (syllable) decision accuracy was facilitated by right pVLPFC disruption, with this effect being maximal at 340 ms, but was unaffected by left pVLPFC disruption. These findings suggest that left pVLPFC mechanisms onset between 300 and 400 ms during phonological processing of words, with these mechanisms appearing necessary for effective episodic encoding. In contrast, disruption of correlated mechanisms in right pVLPFC facilitates encoding, perhaps by inducing a functional shift in the mechanisms engaged during learning.
Evaluations, Referents of Support, and Political Action in New Democracies
Authors: Catterberg Gabriela
Published: March 2005

Discussions of political participation originally centered on cultural explanation, thus emphasizing the dynamics between cognitive and affective orientations of mass populations toward their polities and the role of the self in the political system (Gamson 1968; Easton 1965; Almond and Verba 1963; Dahl 1961; Campbell et al. 1960). Positive evaluations induce involvement, while negative attitudes hinder it. Despite “institutional” criticism, contemporary studies provide ample evidence for the validity of cultural explanations in comprehending protest behavior in post-industrial societies (Dalton 2001; Norris 1999; Klingemann 1999; Inglehart 1997; Jennings 1990). To understand involvement in elite-challenging activities in new democracies, however, the cultural premises should be re-specified. Not only the types, but also the referents of support, have had differentiated effects in citizens’ propensity to participate during the third wave of democratization. Specifically, I claim that support for the new political institutions positively affected participation, while assessments of incumbent authorities negatively impacted engagement after regime change in Latin American and Eastern and Central European nations. Probit estimations using data from the 1995-2001 World Values Surveys support this proposition while they also suggest that participation was mainly influenced by the strength of their orientations toward democracy at similar levels of governmental discontent between two individuals.
Social Institutions and Sanctioned Behaviors: A Cross-National Study
Authors: Parboteeah K. Praveen , Hoegl Martin , Cullen John B.
Published: March 2005

This research considers important social institutions (e.g., the economic system, the level of industrialization, the level of social inequality, and the degree of religiosity) as determinants of individuals’ justifications to commit socially sanctioned behaviors. Using factor analyses on data from 32,734 individuals located in 27 nations, we find that regardless of country, all individuals group 23 socially sanctioned behaviors uniformly in three categories, which we term controversial behaviors (e.g., abortion), peccadilloes (e.g., keeping money found), and illegal behaviors (e.g., political assassinations). We used Hierarchical Linear Modeling (HLM) to test the country-level effects of the social institutions on individuals’ ability to justify these three types of sanctioned behaviors. The results confirm that the social institutions influence individuals’ justifications of sanctioned behaviors, above and beyond important individual-level control variables included in the HLM analyses. The economic system (degree of socialism) and the level of industrialization show positive effects on all three types of sanctioned behaviors. Social inequality has a positive effect on illegal behaviors and peccadilloes, but a negative effect on controversial behaviors. Religiosity affects illegal behaviors positively and controversial behaviors negatively with no significant influence on peccadilloes.
National Identity Issues in the New German Elites: A Study of German University Students
Authors: Ezell Elizabeth D. , Seeleib-Kaiser Martin , Tiryakian Edward A.
Published: March 2005

This empirical study treats German university students as a rising elite. After discussing the broader sociohistorical context of German national identity in recent decades, this study analyzes (a) students’ attitudes and perceptions on issues related to nationalism, national identity, and inclusion, and (b) the extent to which the “Wall in the Mind” as a psychological chasm persists in the new post-cold war generation of West and East Germans. Survey data were obtained from a sample of 544 students at 11 universities in the three areas of Germany: West Germany, East Germany, and Berlin.

A major finding on the issue of national identity, as manifested in common symbols and common tasks, is a blurring of regional differences, with no significant differences found by age or gender. Overall, students reject “traditional” nationalism in favor of a “post-national” commitment to transnational values such as human rights and social equality for all. A significant majority feel there is a common German culture and that East and West Germans are forming one people; one whose future lies in being part of the European Union. We conclude there may be an emergent trend among university students of a post-national identity of being German-in-Europe, which warrants further comparative research.
Organizational Commitment and Conflicting Values: The Impact of Systems of Norms in Six Western Countries
Authors: Hult Carl
Published: March 2005

This study compares organizational commitment in six western countries: USA, Great Britain, New Zealand, Germany, Norway, and Sweden. The main focus is on the hypothesized existence of conflicting values due to different systems of norms. The assumption made is that the central norms, values, and expectations in any particular work organization, originate in a more general technical/economic system of norms; and that subordinated groups, supporters of left-wing values, those identifying with lower social classes, and union members all espouse other systems of norms, which are not entirely compatible with this technical/economic system, and that these groups are therefore likely to display lower organizational commitment than other groups. The results in this paper do suggest the existence of conflicting norms and that this has implications for organizational commitment. The most noteworthy finding is that organizational commitment correlates with right-wing political values in five of the six countries. Other similarities and differences between the countries are also identified and discussed, and new avenues for further comparative research are suggested.
A Statistical Conversion Technique: Objective and Perceptive Financial Measures of the Performance Construct
Authors: Tehrani Minoo , Noubary Reza
Published: March 2005

This study develops a statistical technique that allows comparison of objective and perceptive financial measures of the performance construct. The proposed technique provides a simple and statistically meaningful method for conversion of objective or archival financial data into scales that can be used for testing the convergent validity with corresponding perceptive measures of performance. Use of the proposed technique can enhance flexibility in application of data collected from different sources and strengthen the generalizability of the findings across studies in the strategic management literature. Empirical data of performance measures are used to demonstrate the use of the technique.
Scholarly Journals as Producers of Knowledge: Theory and Empirical Evidence Based on Data Envelopment Analysis
Authors: McWilliams Abagail , Siegel Donald , Van Fleet David D.
Published: March 2005

There have been numerous studies that rank journals based on relative quality. These have generally failed to address some important theoretical and empirical issues relating to productivity. As an alternative, the authors outline a theoretical framework in which an academic journal is considered to be a “producer” of intellectual output. Using the field of management as an example, the authors specify the inputs and outputs of the production process and estimate the relative efficiency of journals using Data Envelopment Analysis. The derived measures of relative productivity are then used to develop a productivity ranking of journals. To explain why some journals use inputs more efficiently than others, the authors regress the estimates of relative efficiency on a set of managerial factors and suggest means to increase relative efficiency. The authors find that increasing the size of the editorial board and reducing both the subscription price and the acceptance rate will enhance the relative performance of an academic journal.
Organizational Behaviour across Cultures
Authors: Fischer Ronald , Ferreira Maria Cristina , Assmar Eveline Maria Leal , Redford Paul , Harb Charles
Published: March 2005

The present article has two objectives. First, general issues for developing and testing cross cultural multi-level models such as variable identification, measurement, sampling and data analysis are discussed. A second aim is to illustrate some of these issues by developing a multi-level framework incorporating variables at an individual, organizational and national level. The goal is to explain cross cultural differences in extra-role behaviour. Based on a review of previous multi-level research and cross cultural research it is proposed that the effect of national culture on work attitudes and behaviour is mediated by organizational practices. The framework is formulated using recent recommendations for the development of multi-level models.
Subcultural Values and Violent Delinquency
Authors: Ousey Graham C. , Wilcox Pamela
Published: March 2005

This study extends research in the subculture of violence tradition by examining the simultaneous effects of individual- and aggregate-level proviolence values on violent behavior. With data from a survey of 3,690 seventh-grade students nested within 65 Kentucky schools, we found that an initially observed between-school effect of violent values on in-school violent behavior is not a contextual effect. Rather, the between-school effect of violent values is primarily a reflection of the individual-level association between violent values and violent behavior. Moreover, we found that the effect of individual values remains evident after measures of impulsivity and exposure to violent peers are controlled. No evidence of cross-level interaction effects involving individual values and the school-level violent value context was found.
Bioinformatics analysis of the locus for enterocyte effacement provides novel insights into type-III secretion
Authors: Pallen Mark J , Beatson Scott A , Bailey Christopher M
Published: March 2005

Background

Like many other pathogens, enterohaemorrhagic and enteropathogenic strains of Escherichia coli employ a type-III secretion system to translocate bacterial effector proteins into host cells, where they then disrupt a range of cellular functions. This system is encoded by the locus for enterocyte effacement. Many of the genes within this locus have been assigned names and functions through homology with the better characterised Ysc-Yop system from Yersinia spp. However, the functions and homologies of many LEE genes remain obscure.

Results

We have performed a fresh bioinformatics analysis of the LEE. Using PSI-BLAST we have been able to identify several novel homologies between LEE-encoded and Ysc-Yop-associated proteins: Orf2/YscE, Orf5/YscL, rORF8/EscI, SepQ/YscQ, SepL/YopN-TyeA, CesD2/LcrR. In addition, we highlight homology between EspA and flagellin, and report many new homologues of the chaperone CesT.

Conclusion

We conclude that the vast majority of LEE-encoded proteins do indeed possess homologues and that homology data can be used in combination with experimental data to make fresh functional predictions.
Application of population pharmacokinetics to cladribine
Authors: Lindemalm Synnöve , Savic Radojka M , Karlsson Mats O , Juliusson Gunnar , Liliemark Jan , Albertioni Freidoun
Published: March 2005

Background

The nucleoside analog cladribine is used for the treatment of a variety of indolent B- and T-cell lymphoid malignancies. The primary aim of the study was to evaluate the population distribution of pharmacokinetic parameters in patients undergoing treatment with cladribine and to detect the influence of different covariates on the pharmacokinetic parameters.

Methods

This pharmacokinetic study presents the results of a retrospective population pharmacokinetic analysis based on pooled data from 161 patients, who were given cladribine in different administration routes in various dosing regimens. The plasma concentrations of cladribine were determined by reversed-phase high-performance liquid chromatography using a solid phase extraction with a limit of quantitation of 1 nM using 1 mL of plasma.

Results

A three compartment structural model best described the disposition of cladribine. Clearance was found to be 39.3 L/hour, with a large interindividual variability. The half-life for the terminal phase was 16 hours. Bioavailability was 100% and 35% for subcutaneous and oral administration, respectively, with low interindividual variability. None of the investigated covariates were found to be correlated with the pharmacokinetic parameters.

Conclusion

As interindividual variability in apparent clearance after oral administration was not significantly higher compared to that following infusion, cladribine could be administered orally instead of intravenously if compensated for its lower bioavailability. Individualized dosing on basis of body surface area or weight does not represent an improvement in this study as compared to administering a fixed dose to all patients.
The chalcone butein from Rhus verniciflua Stokes inhibits clonogenic growth of human breast cancer cells co-cultured with fibroblasts
Authors: Samoszuk Michael , Tan Jenny , Chorn Guillaume
Published: March 2005

Background

Butein (3,4,2',4'-tetrahydroxychalone), a plant polyphenol, is a major biologically active component of the stems of Rhus verniciflua Stokes. It has long been used as a food additive in Korea and as an herbal medicine throughout Asia. Recently, butein has been shown to suppress the functions of fibroblasts. Because fibroblasts are believed to play an important role in promoting the growth of breast cancer cells, we investigated the ability of butein to inhibit the clonogenic growth of small numbers of breast cancer cells co-cultured with fibroblasts in vitro.

Methods

We first measured the clonogenic growth of small numbers of the UACC-812 human breast cancer cell line co-cultured on monolayers of serum-activated, human fibroblasts in the presence of butein (2 μg/mL) or various other modulators of fibroblast function (troglitazone-1 μg/mL; GW9662-1 μM; meloxican-1 μM; and 3,4 dehydroproline-10 μg/mL). In a subsequent experiment, we measured the dose-response effect on the clonogenic growth of UACC-812 breast cancer cells by pre-incubating the fibroblasts with varying concentrations of butein (10 μg/ml-1.25 μg/mL). Finally, we measured the clonogenic growth of primary breast cancer cells obtained from 5 clinical specimens with normal fibroblasts and with fibroblasts that had been pre-treated with a fixed dose of butein (2.5 μg/mL).

Results

Of the five modulators of fibroblast function that we tested, butein was by far the most potent inhibitor of clonogenic growth of UACC-812 breast cancer cells co-cultured with fibroblasts. Pre-treatment of fibroblasts with concentrations of butein as low as 2.5 μg/mL nearly abolished subsequent clonogenic growth of UACC-812 breast cancer cells co-cultured with the fibroblasts. A similar dose of butein had no effect on the clonogenic growth of breast cancer cells cultured in the absence of fibroblasts. Significantly, clonogenic growth of the primary breast cancer cells was also significantly reduced or abolished when the tumor cells were co-cultured with fibroblasts that had been pre-treated with a fixed dose of butein.

Conclusion

We conclude that fibroblasts pre-treated with non-toxic doses of butein (a natural herbal compound) no longer support the clonogenic growth of small numbers of primary breast cancer cells seeded into co-cultures. These results suggest that interference with the interaction between fibroblasts and breast cancer cells by the natural herbal compound, butein, should be further investigated as a novel experimental approach for possibly suppressing the growth of micrometastases of breast cancer.
A qualitative study of the perceptions and experiences of Pre-Registration House Officers on teamwork and support
Authors: Lempp Heidi , Cochrane Mac , Rees John
Published: March 2005

Background

Following the implementation of a new final Year 5 curriculum in one medical school we carried out a study to explore the experience of the transition from final student year to Pre-Registration House Officer (PRHO). This study looks at the experiences of two successive cohorts of PRHOs in relation to team work, support and shared responsibility in their transition from final year students to qualified doctors. The involvement of PRHOs in teams is likely to change in the development of Foundation programmes.

Methods

A qualitative study with semi-structured interviews with 33 PRHOs, stratified by gender, ethnicity and maturity, from two study cohorts, qualifying in 2001 and 2002, from one medical school in the UK, in their first three months following medical graduation.

Results

Most PRHOs reported positive experiences for their inclusion as a full member of their first ward teams. This contributed to their increasing confidence and competence in this early period of career transition. However, a number of organisational barriers were identified, e.g. incomplete teams, shift work, which produced problems in their integration for one third of newly qualified doctors.

Conclusion

Recently introduced policies, intended to improve the working lives of newly qualified doctors have produced both benefits and unintended adverse impacts on PRHOs. The changes of the new PRHO Foundation programme will have further impact. Foundation doctors may need to relate to wider teams with more interaction and less protection. Such changes will need to be managed carefully to protect the PRHO at a vulnerable time.
BioAfrica's HIV-1 Proteomics Resource: Combining protein data with bioinformatics tools
Authors: Doherty Ryan S , De Oliveira Tulio , Seebregts Chris , Danaviah Sivapragashini , Gordon Michelle , Cassol Sharon
Published: March 2005

Most Internet online resources for investigating HIV biology contain either bioinformatics tools, protein information or sequence data. The objective of this study was to develop a comprehensive online proteomics resource that integrates bioinformatics with the latest information on HIV-1 protein structure, gene expression, post-transcriptional/post-translational modification, functional activity, and protein-macromolecule interactions. The BioAfrica HIV-1 Proteomics Resource http://bioafrica.mrc.ac.za/proteomics/index.html is a website that contains detailed information about the HIV-1 proteome and protease cleavage sites, as well as data-mining tools that can be used to manipulate and query protein sequence data, a BLAST tool for initiating structural analyses of HIV-1 proteins, and a proteomics tools directory. The Proteome section contains extensive data on each of 19 HIV-1 proteins, including their functional properties, a sample analysis of HIV-1HXB2, structural models and links to other online resources. The HIV-1 Protease Cleavage Sites section provides information on the position, subtype variation and genetic evolution of Gag, Gag-Pol and Nef cleavage sites. The HIV-1 Protein Data-mining Tool includes a set of 27 group M (subtypes A through K) reference sequences that can be used to assess the influence of genetic variation on immunological and functional domains of the protein. The BLAST Structure Tool identifies proteins with similar, experimentally determined topologies, and the Tools Directory provides a categorized list of websites and relevant software programs. This combined database and software repository is designed to facilitate the capture, retrieval and analysis of HIV-1 protein data, and to convert it into clinically useful information relating to the pathogenesis, transmission and therapeutic response of different HIV-1 variants. The HIV-1 Proteomics Resource is readily accessible through the BioAfrica website at: http://bioafrica.mrc.ac.za/proteomics/index.html
Orally administered OVA/CpG-ODN induces specific mucosal and systemic immune response in young and aged mice
Authors: Alignani Diego , Maletto Belkys , Liscovsky Miriam , Rópolo Andrea , Morón Gabriel , Pistoresi-Palencia María C
Published: March 2005

We have previously demonstrated that subcutaneously administered ovalbumin (OVA) plus synthetic oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG-ODN) as adjuvant stimulate cellular and humoral immunity and promote T helper cell type 1 differentiation in aged mice. The present study assessed the ability of CpG-ODN to induce an OVA-specific immune response after oral immunization in young (3-month-old) and aged (18-month-old) BALB/c mice. Oral OVA/CpG-ODN immunization induces a similar OVA-specific T cell-proliferative response (in mucosal and systemic tissues), immunoglobulin G (IgG) in plasma, and IgA in intestinal washes in both groups of ages. The OVA-specific humoral immune response observed in aged mice was similar to the one observed in young mice, peaking at day 7 after the last oral immunization and was present over 40 days after the last oral immunization. The pattern of cytokines released in culture supernatants in both groups of mice was similar, with specific interferon-γ secretion in the absence of interleukin-5 responses. These results provide evidence that orally administered OVA/CpG-ODN induces a young-like, specific, immune response against OVA in aged mice, showing that CpG-ODN might be used as a mucosal adjuvant during aging.
The live vaccine strain ofFrancisella tularensisreplicates in human and murine macrophages but induces only the human cells to secrete proinflammatory cytokines
Authors: Bolger Courtney E , Forestal Colin A , Italo Jaime K , Benach Jorge L , Furie Martha B
Published: March 2005

Francisella tularensis is the highly infectious agent of tularemia, a disease that can prove fatal in humans. An attenuated live vaccine strain (LVS) of this bacterium is avirulent in man but produces lethal illness in mice. As a step toward understanding the species specificity of the LVS, we compared its interactions with murine and human leukocytes. The bacterium replicated within murine bone marrow-derived macrophages (muBMDM), human monocyte-derived macrophages (huMDM), and freshly isolated human monocytes. However, the murine and human phagocytes differed in their ability to secrete proinflammatory cytokines in response to the LVS. The huMDM released large amounts of CXC chemokine ligand 8 (CXCL8) and CC chemokine ligand 2 when incubated with live or killed LVS organisms, and live bacteria also elicited production of interleukin-1β (IL-1β). Furthermore, human monocytes secreted CXCL8, IL-1β, and tumor necrosis factor α in response to various bacterial preparations. In contrast, muBMDM produced little to no proinflammatory cytokines or chemokines when treated with any preparations of the LVS. Clearly, human and murine macrophages support growth of this bacterium. However, the greater proinflammatory response of human leukocytes to F. tularensis LVS may contribute to the avirulence of this strain in the human host.
Relationship between Released Strain and Growth Rate in 39 Year-Old Tectona grandis Planted in Indonesia
Authors: Wahyudi I. , Okuyama T. , Hadi Y. Sudo , Yamamoto H. , Watanabe H. , Yoshida M.
Published: March 2005

In order to clarify the growth stress mechanism of tree species in tropical forest, peripheral and internal
longitudinal released strains in 39 year-old teak (Tectona grandis) trees planted in West Java, Indonesia
were investigated using the strain-gauge technique. Results showed that both of the peripheral and internal
longitudinal released strains were not affected by the rate of growth of the trees. However, released
strains distribution inside tree stem, from pith to periphery, were significantly affected by growth rate;
slow growing trees generate steeper released strain gradients.
Dielectric Relaxation Based on Adsorbed Water in Wood Cell Wall under Non-Equilibrium State 2
Authors: Jinzhen C. , Guangjie Z.
Published: March 2005

In order to explain, on molecular level, the unusualness of wood physical properties under moisture non-equilibrium
state, the dielectric temperature and frequency spectra of Sikkim spruce (Picea spinulosa
Griff.) specimens were measured during the adsorption process in 20°C, 60% R.H. environment. Furthermore,
the dielectric relaxation based on adsorbed water was separated from that based on the
methanol groups in the amorphous region of wood cell wall, so that the thermodynamic quantities of
adsorbed water associated with the adsorption process could be evaluated. Consequently, the molecular
reorientation model of adsorbed water molecules during the dielectric relaxation process was constructed.
The results show that the activation enthalpy ∆H and activation entropy ∆S of adsorbed water both
increase linearly with the adsorption time. During the initial adsorption period ∆S appears as a negative
value. According to the values of thermodynamic quantities, especially the ∆H values, it can be inferred
that the average number of hydrogen bonds formed between each adsorbed water molecule with its surrounding
wood adsorption sites increases gradually with developing adsorption. The model based on the
obtained data in this experiment shows that after 7 hours' adsorption the number is between two and
three, after 24 hours it is three and later it approaches four.
Construction of J-R Curves Using the Common and Concise Formats
Authors: Donoso JR , Zahr J , Landes JD
Published: March 2005

A new method for constructing J-R curves is presented, which directly generates the J-Δa relation in a closed, analytical form. This new method makes use of the Concise Format and the Common Format, both developed by Donoso and Landes. These formats relate load, P, to ligament length, b, and displacement — in the elastic and in the plastic deformation ranges, respectively — and have proved useful in calculations in fracture mechanics. Key to the method is the postulate of a “crack growth law” —a power-law relation between crack extension, Δa, and plastic displacement — used to express Jpl in terms of material properties, size parameters, and crack extension, giving rise to a Jpl-Δa analytical expression, similar to the power law J = CI(Δa)C2 suggested in ASTM Standard Test Method for Measurement of Fracture Toughness (E 1820). A few examples are included to show the use of the method, and comparisons are made with suggested in ASTM Standard Test Method for Measurement of Fracture Toughness (E 1820). A few examples are included to show the use of the method, and comparisons are made with J-Δa curves calculated as per ASTM E 1820.
C-φ Characterization Model for Design of Asphalt Mixtures and Asphalt Pavements
Authors: Fwa TF , Tan SA
Published: March 2005

This paper reports the results of a research effort initiated in the early 1990s to develop a C-φ (cohesion-angle of friction) characterization model for the design of asphalt mixtures and asphalt pavements. It is demonstrated that, since the model is based on the fundamental material properties represented by C and φ, it can derive analytically other asphalt mix design parameters such as Marshall stability and flow, and indirect tensile strength. The C-φ characterization model therefore offers a useful basis for the development of a comprehensive design framework that integrates asphalt mix design with asphalt pavement structural design. To demonstrate this capability, the research developed an empirical-mechanistic rutting prediction model of asphalt pavement layer using the C-φ characterization model. In addition, the model allows stresses and strains under design loading to be computed, which can be applied as input to structural analysis for asphalt material selection and pavement thickness design.
Optimum Design of Gas Pycnometers for Determining the Volume of Solid Particles
Authors: Tamari S , Aguilar-Chávez A
Published: March 2005

Gas pycnometry is based on Boyle-Mariotte's law. There are three kinds of gas pycnometers reported in the literature: “constant-volume,” “variable-volume,” and “comparative.” These instruments are widely used to determine the volume—and thus the density—of granular, porous, or soluble compounds (e.g., rocks, coal, pigments, ceramic, drugs, seeds). However, many users do not know the optimum-use conditions of their gas pycnometer. This work provides a synthesis of recent studies about the optimum design of the gas pycnometers. It seems possible to use commercially available components for constructing gas pycnometers that can determine the volume of solid particles with a relative standard uncertainty smaller than 0.25 %. Compared to other gas pycnometers, the constant-volume pycnometer presents several practical advantages.
The Class B Scavenger Receptor CD36 Mediates Free Radical Production and Tissue Injury in Cerebral Ischemia
Authors: Cho Sunghee , Park Eun-Mi , Febbraio Maria , Anrather Josef , Park Laibaik , Racchumi Gianfranco , Silverstein Roy L. , Iadecola Costantino
Published: March 2005

The class B scavenger receptor CD36 is involved in the cytotoxicity associated with inflammation, but its role in the inflammatory reaction that accompanies cerebral ischemia has not been examined. In this study, we investigated whether CD36 contributes to the brain damage produced by cerebral ischemia. The middle cerebral artery was transiently occluded in wild-type mice and in mice deficient in CD36. In wild-type mice, CD36 protein expression was increased in the ischemic brain, such that it was located predominantly in cells expressing the microglia/macrophage marker CD11b. The infarct produced by middle cerebral artery occlusion was 49% smaller in CD36-null mice than in wild-type controls, an effect associated with improved neurological function. The attenuation in brain injury in CD36 nulls could not be attributed to differences in cerebral blood flow during ischemia-reperfusion. However, the increase in reactive oxygen species (ROS) produced by cerebral ischemia was markedly attenuated in CD36-null mice in the early stage after reperfusion. The data unveil a previously unrecognized role of CD36 in ischemia-induced ROS production and brain injury. Modulation of CD36 signaling may provide a new strategy for the treatment of ischemic stroke.
Functional Maturation of the Macaque's Lateral Geniculate Nucleus
Authors: Movshon J. Anthony , Kiorpes Lynne , Hawken Michael J. , Cavanaugh James R.
Published: March 2005

Vision in infant primates is poor, but it is not known which structures in the eye or brain set the main limits to its development. We studied the visual response properties of 348 neurons recorded in the lateral geniculate nucleus (LGN) of macaque monkeys aged 1 week to adult. We measured spatial and temporal frequency tuning curves and contrast responses with drifting achromatic sinusoidal gratings. Even in animals as young as 1 week, the main visual response properties of neurons in the magnocellular (M) and parvocellular (P) divisions of the LGN were qualitatively normal, including the spatial organization of receptive fields and the characteristic response properties that differentiate M- and P-cells. At 1 and 4 weeks, spatial and temporal resolution were less than one-half of adult values, whereas contrast gain and peak response rates for optimal stimuli were about two-thirds of adult values. Adult levels were reached by 24 weeks. Analysis of correlations between S-potentials representing retinal inputs and LGN cells suggested that the LGN follows retinal input as faithfully in infants as in adults, implicating retinal development as the main driving force in LGN development. Comparisons with previously published psychophysical data and ideal observer models suggest that the relatively modest changes in LGN responses during maturation impose no significant limits on visual performance. In contrast to previous studies, we conclude that these limits are set by neural development in the visual cortex, not in or peripheral to the LGN.
Learning to Like: A Role for Human Orbitofrontal Cortex in Conditioned Reward
Authors: Cox Sylvia M. L. , Andrade Alexandre , Johnsrude Ingrid S.
Published: March 2005

A great deal of human behavior and motivation is based on the intrinsic emotional significance of rewarding or aversive events, as well as on the associations formed between such emotional events and concurrent environmental stimuli. Recent functional neuroimaging studies have implicated the ventral striatum, orbitofrontal cortex (OFC), and amygdala in the representation of reward values and/or in the anticipation of rewarding events. Here, we use functional magnetic resonance imaging to compare brain activation during the presentation of reward with that during presentation of (conditioned) stimuli that have been paired previously with reward. Specifically, we aimed to investigate conditioned reward in the absence of explicit reward anticipation. Twenty-two healthy volunteers were scanned while monochrome visual patterns were incidentally associated with reward or negative feedback in the context of a simple card game. In the subsequent session, visual patterns, including the conditioned stimuli, were presented without reward or negative feedback, and the affective valence of these stimuli was assessed behaviorally. The presentation of reward compared with negative feedback activated the ventral striatum and OFC. Activation in the same OFC region was observed when, in the subsequent session, subjects passively viewed the stimuli that had been paired with reward, without the administration of reward and with subjects being essentially unaware of the conditioning manipulation. These findings suggest that the OFC in humans plays an important role in the representation of both rewarding stimuli and conditioned stimuli that have acquired reward value.
NMDA Receptor-Dependent Synaptic Translocation of Insulin Receptor Substrate p53 via Protein Kinase C Signaling
Authors: Hori Kei , Yasuda Hiroki , Konno Daijiro , Maruoka Hisato , Tsumoto Tadaharu , Sobue Kenji
Published: March 2005

The activity-dependent remodeling of postsynaptic structure is a fundamental process underlying learning and memory. Insulin receptor substrate p53 (IRSp53), a key player in cytoskeletal dynamics, is enriched in the postsynaptic density (PSD) fraction, but its significance in synaptic functions remains unclear. We report here that IRSp53 is accumulated rapidly at the postsynaptic sites of cultured hippocampal neurons after glutamate or NMDA stimulation in an actin cytoskeleton-dependent manner. Pharmacological profiles showed that a PKC inhibitor, but not other kinase inhibitors, specifically suppressed the synaptic translocation of IRSp53 in response to NMDA, and the selective activation of PKC with phorbol ester markedly induced the synaptic translocation. Reverse transcriptase-PCR and Western blotting showed that IRSp53-S is the major isoform expressed in cultured hippocampal neurons. The synaptic targeting of IRSp53-S was found to be mediated through N-terminal coiled-coil domain and the PDZ (PSD-95/Discs large/zona occludens-1)-binding sequence at its C-terminal end and regulated by the PKC phosphorylation of its N terminus. In electrophysiological experiments, overexpression of IRSp53-S wild type and IRSp53-S mutant that is spontaneously accumulated at the postsynaptic sites enhanced the postsynaptic function as detected by an increased miniature EPSC amplitude. These data suggest that IRSp53 is involved in NMDA receptor-linked synaptic plasticity via PKC signaling.
A Functional Genetic Variation of the Serotonin (5-HT) Transporter Affects 5-HT1AReceptor Binding in Humans
Authors: David Sean P. , Murthy Naga Venkatesha , Rabiner Eugenii A. , Munafó Marcus R. , Johnstone Elaine C. , Jacob Robyn , Walton Robert T. , Grasby Paul M.
Published: March 2005

In humans, 5-HT1Areceptors are implicated in anxiety and depressive disorders and their treatment. However, the physiological and genetic factors controlling 5-HT1Areceptor expression are undetermined in health and disease. In this study, the influence of two genetic factors on 5-HT1Areceptor expression in the living human brain was assessed using the 5-HT1A-selective positron emission tomography (PET) ligand [11C]WAY 100635. After the genotyping of 140 healthy volunteers to study population frequencies of known single nucleotide polymorphisms (SNPs) in the 5-HT1Areceptor gene, the influence of the common SNP [(-1018) C>G] on 5-HT1Areceptor expression was examined in a group of 35 healthy individuals scanned with [11C]WAY 100635. In the PET group, we also studied the influence of a common variable number tandem repeat polymorphism [short (S) and long (L) alleles] of the 5-HT transporter (5-HTT) gene on 5-HT1Areceptor density. Whereas, the 5-HT1Areceptor genotype did not show any significant effects on [11C]WAY 100635 binding, 5-HT1Areceptor binding potential values were lower in all brain regions in subjects with 5-HTTLPR short (SS or SL) genotypes than those with long (LL) genotypes. Although the PET groups are necessarily a small sample size for a genetic association study, our results demonstrate for the first time that a functional polymorphism in the 5-HTT gene, but not the 5-HT1Areceptor gene, affects 5-HT1Areceptor availability in man. The results may offer a plausible physiological mechanism underlying the association between 5-HTTLPR genotype, behavioral traits, and mood states.