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At least 469 records · Page 26Linked to original sources
PubMed2004

Use of X-ray computed microtomography for non-invasive determination of wood anatomical characteristics.

Quantitative analysis of wood anatomical characteristics is usually performed using classical microtomy yielding optical micrographs of stained thin sections. It is time-consuming to obtain high quality cross-sections from microtomy, and sections can be damaged. This approach, therefore, is often impractical for those who need quick acquisition of quantitative data on vessel characteristics in wood. This paper reports results of a novel approach using X-ray computed microtomography (microCT) for non-invasive determination of wood anatomy. As a case study, stem wood samples of a 2-year-old beech (Fagus sylvatica L.) and a 3-year-old oak (Quercus robur L.) tree were investigated with this technique, beech being a diffuse-porous and oak a ring-porous tree species. MicroCT allowed non-invasive mapping of 2-D transverse cross-sections of both wood samples with micrometer resolution. Self-developed software 'microCTanalysis' was used for image processing of the 2-D cross-sections in order to automatically determine the inner vessel diameters, the transverse cross-sectional surface area of the vessels, the vessel density and the porosity with computer assistance. Performance of this new software was compared with manual analysis of the same micrographs. The automatically obtained results showed no significant statistical differences compared to the manual measurements. Visual inspection of the microCT slices revealed very good correspondence with the optical micrographs. Statistical analysis confirmed this observation in a more quantitative way, and it was, therefore, argued that anatomical analysis of optical micrographs can be readily substituted by automated use of microCT, and this without loss of accuracy. Furthermore, as an additional application of microCT, the 3-D renderings of the internal microstructure of the xylem vessels for both the beech and the oak sample could be reconstructed, clearly showing the complex nature of vessel networks. It can be concluded that the use of microCT in wood science offers an interesting potential for all those who need quantitative data of wood anatomical characteristics in either the 2-D or the 3-D space.

Fagus↗
PubMedDate not supplied

Exo/Astrobiology in Europe.

The question of the chemical origins of life is engraved in the European scientific patrimony as it can be traced back to the pioneer ideas of Charles Darwin, Louis Pasteur, and more recently to Alexander Oparin. During the last decades, the European community of origin of life scientists has organized seven out of the twelve International Conferences on the Origins of Life held since 1957. This community contributed also to enlarge the field of research to the study of life in extreme environments and to the search for extraterrestrial life, i.e. exobiology in its classical definition or astrobiology if one uses a more NASA-inspired terminology. The present paper aims to describe the European science background in exo/astrobiology as well as the project of a European Network of Exo/Astrobiology.

Astronomy↗
PubMed2003

Effects of problem-based learning curricula on faculty learning: new lenses, new questions.

Literature on the impact of problem-based learning (PBL) in medical education has short-changed important questions about the effect of PBL curricula on faculty learning and on faculty knowledge of their subject matter. This paper opens up new questions about the impact of PBL in medical colleges and other health sciences by focusing attention on its effects on faculty learning, on collegial networks in medical colleges, and, consequently, on other scholarly work by faculty. A brief review of research on the effects of PBL on faculty and faculty development is followed by a synthesis of relevant research findings from research on teaching and faculty learning in other disciplines. A new conceptual framework, drawn from the educational paradigms, methods and empirical findings from those other areas of higher education research and research on secondary school teaching, is applied to designing, examining, and evaluating problem-based learning. Viewing faculty as learners prompts a new research agenda including questions such as: What do faculty members learn by participating in integrative, interdisciplinary problem-based learning courses? How? How is that learning related to or integrated with other aspects of their scholarly work?

Attitude↗
PubMed2004

Crossmaps: visualization of overlapping relationships in collections of journal papers.

A crossmapping technique is introduced for visualizing multiple and overlapping relations among entity types in collections of journal articles. Groups of entities from two entity types are crossplotted to show correspondence of relations. For example, author collaboration groups are plotted on the x axis against groups of papers (research fronts) on the y axis. At the intersection of each pair of author group/research front pairs a circular symbol is plotted whose size is proportional to the number of times that authors in the group appear as authors in papers in the research front. Entity groups are found by agglomerative hierarchical clustering using conventional similarity measures. Crossmaps comprise a simple technique that is particularly suited to showing overlap in relations among entity groups. Particularly useful crossmaps are: research fronts against base reference clusters, research fronts against author collaboration groups, and research fronts against term co-occurrence clusters. When exploring the knowledge domain of a collection of journal papers, it is useful to have several crossmaps of different entity pairs, complemented by research front timelines and base reference cluster timelines.

Authorship↗
PubMedDate not supplied

Application of gene expression profiling for validating models of human breast cancer.

While classical histopathologic approaches are invaluable in classifying tumors and understanding aspects of cellular interactions, genomic approaches provide a means to molecularly dissect tumorigenesis. The relationship of gene expression to the development of neoplasia remains an area of intensive research. With the advent of large-scale genomic platforms, alterations in gene expression can be related to the morphological development of cancer. The feasibility of using large-scale genomic analysis platforms has dramatically changed the landscape of biological sciences, as cellular processes must be considered in the context of complex networks. Alterations in gene expression must now be understood in a systems approach in which the relationships between genes expression changes are studied by considering the interplay of multiple regulatory networks. Ultimately, such changes must be understood at the protein level. We have begun to apply this technology to determine changes in gene expression that differentiate various types of mammary cancers that arise in mouse models that have been initiated by different genetic alterations. Ultimately, a molecular catalogue of similarities and differences between rodent and human tumors can be created which will serve to validate or credential particular models for specific experimental purposes, such as preclinical testing. These approaches have led to new insights into molecular pathways involved in oncogenesis, new classifications of human breast cancer, and the identification of new genes that may be relevant to understanding and treating human cancer.

Animals↗
PubMed2004

Vaccinate against aspergillosis! A call to arms of the immune system.

Invasive aspergillosis is a devastating and increasingly common disease, seen almost exclusively in immunosuppressed patients. Immunizing an immunocompromised host would seem to be a formidable task; however, virulence factors and immunogens of the pathogen have now been identified and could be targeted, mapping of the genome sequence of the pathogen will soon be completed, and the protective host immune responses and cytokine networking are better understood. These facts, together with recent advances in vaccine science, make consideration of such an approach now possible. Some populations that are at risk for aspergillosis might be likely candidates for receiving the first vaccinations against aspergillosis, or vaccination of a stem cell donor might be considered in some circumstances. Successful immunizations have been demonstrated in turkeys and mice.

Animals↗
PubMed1996

The Health Care Ethics Consultant, edited by Françoise Baylis.

The Health Care Ethics Consultant marks a stage in the development of ethics consultancy. Ethics consultancy is a manifestation of a newly secularized society in which a new discipline has developed to fill a gap created by the combination of the diminishing influence of traditional moral authorities and the growth of new problems associated with the development of new technology and changes in society and culture. The stated primary objective of the book is to focus attention on an immediate practical problem: the role and responsibilities, the education and training, and the certification and accreditation of health ethics consultants. An edited collection of articles, the book originated as a research project financed by the Social Sciences and Humanities Research Council of Canada, undertaken by a Strategic Research Network which included faculty members from Dalhousie University, McGill University, the University of Toronto, McMaster University and the University of Calgary.

Canada↗
PubMed2006

Mechanisms controlling embryonic stem cell self-renewal and differentiation.

Embryonic stem (ES) cells are pluripotent cells with indefinite replication potential and ability to differentiate into all types of cells. An understanding of the regulatory mechanisms responsible for pluripotency in ES cells is critical for realizing their potential in regenerative medicine and science. Cross-species studies on ES cells have identified pathways and networks that are either fundamental to or species-specific for self-renewal and differentiation. Although pluripotency as an essential function in multicellular organisms is conserved through evolution, mechanisms primed for differentiation contribute substantially to the differences among stem cells derived from different tissues or species. Transcriptome mapping analysis has determined the chromosomal domains of gene coexpression patterns specific to the ES state and demonstrated that regulation of ES cell development is operative at both the local chromosomal domain level and global level. Combinatorial signals from multiple pathways regulate the expression of key intrinsic factors critical for ES cell fate determination. The regulatory core formed by Oct4, Sox2, and Nanog, in particular, activates genes critical for self-renewal and represses genes initiating differentiation, controlling ES cell pluripotency. Here, we review recent findings on mechanisms controlling ES cell development. By integrating data from different sources, we present a global picture of how ES cells reach the decision of self-renewal or differentiation.

Animals↗
PubMed1989

Health science information management and continuing education of physicians. A survey of U.S. primary care practitioners and their opinion leaders.

PURPOSE: To identify self-perceived problems in managing science information needs of U.S. primary practitioners and their opinion leaders. SAMPLE: A two-stage random sample of the American Medical Association's "Masterlist of Physicians" to identify 625 office-based physicians, including general practice, family practice, internal medicine, obstetrics and gynecology, and pediatrics, and 100 physician opinion leaders. DATA COLLECTION: A formal telephone survey was completed for 79% of practitioners and 90% of opinion leaders sampled, using a pretested instrument applied by trained telephone surveyors. RESULTS OF DATA ANALYSIS: Both practitioners and opinion leaders claimed that published reviews were the most useful means of identifying their information needs. When asked about use of six recent clinical advances, that is, "markers," for example, hemoglobin-A1C for diabetic control, as many as one fifth to one half were not using or were not aware of such an advance. Less than 1 in 3 practitioners personally searched the literature when information was needed; 2 in 3 claimed literature volume was unmanageable; 9 of 10 practitioners and opinion leaders assessed the scientific value of literature obtained, primarily from their own experience, with less than 1 in 10 contacting research methods specialists. Respondents suggested various innovations to better manage their science information needs in the future. CONCLUSIONS: Primary practitioners require substantial help in meeting current science information needs. Increase in such resources as "validated reviews" or "expert networks" might help meet these needs.

Education, Medical, Continuing↗
PubMed1998

[Introduction of the Bavarian Scientific Rehabilitation Group].

As a part of the Rehabilitation Research Programme of both the Ministry for Education, Science, Research and Technology and the German Pension Insurance, the Rehabilitation Research Network of Bavaria has begun its work after having completed a planning phase of three years. Under the heading entitled "Patients in Rehabilitation" physical, psychological and social consequences of chronic diseases are addressed from a bio-psycho-social point of view. The network contains ten research projects which are located in different university institutions and rehabilitation clinics all over Bavaria. These projects can be assigned to three thematic clusters: diagnostical and predictor studies; evaluation of treatments; interface problems in rehabilitation. The interventions to be evaluated are aimed at strengthening patients' coping abilities. Wherever feasable, randomized controlled studies are performed. Both economical and gender-specific effects are investigated. A central facility for coordination and methodological consultation was implemented at the University of Würzburg. The network has the objective of both improving the quality of rehabilitation research and education and increasing the resources of institutions doing rehabilitation research in Bavaria.

Forecasting↗
PubMed2001

[DNA arrays: technological aspects and applications].

The Human Genome Project has allowed considerable progress in the construction of physical and genetic maps and the identification of genes involved in human sicknesses. The accelerated accumulation of biological information and knowledge is due in large part to the sequencing projects of other organisms, which in fact paved the way for the Human Genome Project. In parallel, recently developed techniques which take advantage of genomic sequences allow large scale molecular analyses resulting in the functional annotation of many of the proteins represented by these genes. This is the goal of functional genomics. These progresses are at the origin of the present revolution in biomedical research. DNA microarrays are playing a dominant role compared to the other developing technologies since they are relatively easy to make and use and are applicable to numerous scientific inquiries. They allow the simultaneous analysis of several thousands of genes in biological samples from sick or healthy tissues, at the genome or transcriptome level. The data obtained is expected to result in major advances in the health sciences. In addition to an improved understanding of the complex molecular interaction networks of healthy cells and tissues, a more precise genetic characterization of the molecular mechanisms involved in pathology should result in the identification of new therapeutic targets and the development of new medicines. The genetic profiles thus obtained should also permit the definition of new pathologic subclasses not recognizable by traditional clinical factors, as well as new markers for susceptibility to certain illnesses, and new prognostic markers or methods of predicting responses to treatment. In this article, we present the different approaches and potential applications of DNA microarray technology, in particular as applied to cancer research.

Chromosome Mapping↗
PubMed1993

The ESA microgravity database.

To facilitate and optimise access to the results of previous microgravity experiments, ESA is establishing a Microgravity Database (MGDB). The database will give scientists access to descriptions of all experiments related to microgravity research carried out on ESA and NASA missions since the 1960s. MGDB incorporates both a local database available for PCs and Apple Macintoshes, and a remote database which can be accessed via the ESRIN Data Dissemination Network (DDN) and public X.25 networks.

Aerospace Medicine↗
PubMed2001

Southeast Asian perspectives on nutrition needs for the new millennium.

Over the last three decades, there has been significant changes in the lifestyles of commmunities, including food habits, and food purchasing and consumption patterns in the Southeast Asian region. As a result, there is a definite change in the food and nutrition issues in the region. Nutritional deficiencies in many of these countries are slowly being decreased in magnitude. On the other hand, the significant proportions of the population are now faced with the other facet of the malnutrition problem, namely diet-related chronic diseases. However, because of the different stages of socio-economic development, the extent of each of these extremes of the malnutrition problems varies considerably between the different countries in Southeast Asia. Nutrition needs in the new millennium would necessarily differ somewhat among these countries while at the same time, there would be a considerable amount of similarities. This presentation highlights several macro issues that countries in the region may focus on in the near future. Various intervention programmes have been undertaken by authorities to tackle the co-existence of twin faces of malnutrition in many developing countries. It would be desirable to have a blue print of such programmes and activities in the National Plans of Action for Nutrition (NPANs) . The NPAN should be more than a framework or a descriptive document. It should be a tool for action, an operational plan that sets out priorities; identifies projects and activities, with details of implementation such as what, how and when; designates responsibilities and accountability for the activities; identifies resource requirements and their source; and sets out the plan for monitoring and evaluation. One of the main obstacles in the formulation and effective implementation of intervention programmes in developing countries is the lack of comprehensive data on the extent of the problems in many cases and the causes of such problems specificy to the communities concerned. It is thus imperative to identify appropriate research priorities and conduct relevant studies. It is also important to have basic baseline data collected at regular intervals such as nutritional status of communities and dietary intake. To conduct all these activities, it is vital to ensure adequate funding, preferably through establishing a dedicated fund for research. There should be closer collaboration between countries in the region in all nutrition activities to enable sharing of resources, experiences and learn from the mistakes of others. One existing mechanism is through the ASEAN structure. The other existing mechanisms are through WHO and FAO. One other mechanism is through the International Life Sciences Institute (ILSI) Southeast Asian Branch. Closely related to this need for networking is the need for continuing harmonization of approaches to nutrition activities in the region. Current efforts in harmonisation include RDA, nutritional status assessment methodologies and dietary guidelines. Other areas of harmonisation in the near future include nutrition labelling and claims.

Asia, Southeastern↗
PubMedDate not supplied

Science and the courts: a fruitful experiment of interaction.

The authors report on the European Seminar on Hot Genetic Issues and the Courts, held in Pavia (I), September 2005. They examine the new possible concerns regarding bio-sciences practical applications and the stronger need for a closer interaction between jurists, judges and scientists. They highlight the importance of the ENLSC's networking experience in judicial education and the originality of its approach.

Europe↗
PubMed1994

The Health Information Technology Center at the Medical College of Wisconsin.

Everyone working in health care today is overwhelmed by scientific and medical information. Effective use of this information requires access to sophisticated information communications technologies. At the Medical College of Wisconsin, the Health Information Technology Center provides these technologies for biomedical research, medical education, clinical service, and health policy analysis. Several of the center's services are available to community health care providers through the college's Medical Information Network.

Community Participation↗