bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dialogue: a theoretical framework for distance education instructional systems
Authors: Gorsky Paul , Caspi Avner 
Published: February 2005

AbstractThis paper presents a theoretical framework for viewing elements that comprise distance education instructional systems in terms of dialogue. It is assumed that learning is mediated by intrapersonal dialogue and facilitated by interpersonal dialogue. Every resource in a distance education instructional system (eg, instructor availability, asynchronous communication networks, self‐instruction texts, etc) is analysed in terms of the dialogue mode it supports. The framework offers three advantages: (1) a unified, simple, and coherent description of the mechanisms at play in distance education systems, (2) clear‐cut operational definitions, and (3) hypotheses that may be investigated empirically.
Moderate Exercise Induces Different Autonomic Modulations of Sinus and AV Node
Authors: SCHUCHERT ANDREAS , WAGNER STEFAN M. , FROST GABY , MEINERTZ THOMAS 
Published: February 2005

Background: The routine determination of heart rate variability (HRV) from surface ECGs is based on RR intervals because of the difficulty to precisely locate the P‐wave fiducial point on surface ECG recordings. The aim of the study was to assess the changes of RR, PP, and PR intervals at rest and during moderate exercise. The time intervals were determined from atrial and ventricular pacemaker‐mediated intracardiac electrograms.
Methods: Ten patients in sinus rhythm with intrinsic AV node conduction who had received the dual‐chamber pacemaker Logos (Biotronik) were included. High‐resolution atrial and ventricular intracardiac electrograms were transmitted at rest in supine position and during walking to a portable external recorder. Recording sequences of 150 successive heart cycles were used for HRV analyses after computer‐assisted triggering of P and R events. The HRV‐index SDNN and power spectral densities for the low (LF; 0.04–0.15 Hz) as well as high (HF; 0.15–0.40 Hz) frequency bands were determined.
Results: SDNN decreased from 26.0 ± 8.1 ms at rest to 18.3 ± 4.2 ms during exercise for the PP intervals (P < 0.05) and from 26.8 ± 8.1 to 18.4 ± 4.1 ms for the RR intervals (P < 0.05). The LF/HF ratio increased from 2.02 ± 1.3 to 4.5 ± 1.5 in the atrium (P < 0.05) and from 2.0 ± 1.2 to 5.2 ± 1.9 in the ventricle P < 0.05). Comparing atrial and ventricular HRV at both activity levels, no significant differences were observed for the power of LF and HF spectral components. Regarding the PR intervals SDNN, the total power and the LF/HF ratio did not significantly change during exercise.
Conclusions: The described technique enabled to record intracardiac electrograms not only at rest, but also during moderate exercise and to use them for HRV evaluation. The changes of PP and RR, but not of the PR intervals, during exercise indicate that autonomic inputs to the sinus node and AV node are independent from each other. The ventricular HRV seems to derive mainly from variations of the sinus node pulse formation.
Flowers in the clinical setting: Infection risk or workload issue?
Authors: Gould Dinah , Gammon John , Salem Rachel Ben , Chudleigh Jane , Fontenla Marina 
Published: February 2005

Healthcare-associated infection has become a topic of interest to the general public in the United Kingdom, kindled by media accounts of poor hygiene and the risks of cross-infection. In the spring of 2003, one of the broadsheet newspapers published an article debating the hygiene and infection risks associated with cut flowers brought into clinical areas. There were reports that in many wards this practice is no longer allowed because flowers are considered dirty, trigger allergies and the water is regarded as harbouring bacteria, leading to infection. Discussion with infection control experts revealed that questions concerning the risks associated with flowers are among those most frequently asked. A literature search was undertaken to establish the evidence base, and a questionnaire study was performed with a purposive sample of 39 nurses to document how they manage flowers in the clinical setting. Empirical research studies were difficult to obtain. Early work had been undertaken to explore the added workload associated with maintaining fresh flowers and ways of reducing it. Later studies revealed that the water in flower vases and cut plants both harbour large numbers of Gram-negative pathogens. Cross-infection and cases of clinical infection have never been documented, thus flowers have not been considered a risk, except to severely immunocompromised patients. However, scrutiny of the more general literature relating to Gram-negative sepsis indicated that cross-infection has been documented from a wide range of environmental sources and it is possible that it may take place from flowers via the hands of staff if they are not properly decontaminated. Nevertheless, these risks can be reduced by scrupulous attention to hand hygiene and commonsense measures. Over half the nurses (n = 26, 66.6%) thought that flowers constituted an infection risk and a number of other disadvantages were cited. Most nurses (n = 31, 80%) were not in favour of flowers in the clinical setting and there was some evidence that this attitude was related to the amount of work generated, with infection and other risks used to justify it. Interest in the topic was considerable and the results can be used to stimulate discussion and emphasise the importance of controlling health-related infection.
Using ethnography (or qualitative methods) to investigate drug errors: A critique of a published study
Authors: Armitage Gerry , Holder Award , Hodgson Ian 
Published: February 2005

The effects of drug errors and any consequent adverse events frequently impact on patients, their relatives and professional carers. Furthermore, the financial cost to the National Health Service is considerable (DoH, 2000; DoH, 2001; DoH, 2004). In a study of two London teaching hospitals, Vincent et al. (2001) found that 10% of patients are exposed to an adverse event, which adds a mean 8.5 days to their hospital stay. Drug errors are recurrently reported to account for between 10 and 20% of all adverse events (DoH, 2004). In response to Department of Health policy, NHS trusts are changing their approach to the management of error to encourage more reporting. The emphasis is on openness and support, and individual and organisational learning rather than blame. Research designed to increase a knowledge of the aetiology and context of drug errors should be carefully constructed and include qualitative methods which, if implemented according to established convention, can reflect the approaches described above. This paper will critique a recently published study that focused on nursing practice and was, in our view, inappropriately described as ethnographic. The study undoubtedly adds to the body of existing knowledge about drug errors and, crucially, if the study contributes to improved patient safety, it must, fundamentally, be valued. Nevertheless, some qualitative research conventions were broken and, as such, it is suggested, some opportunities for a broader understanding and for learning may have been lost. The critique will lead to a range of recommendations about future qualitative studies in this research domain which, it is argued, could produce a fuller picture of the context, culture and, perhaps, even the cause of error.
Recognising the challenges of collaborative, multi-site research
Authors: Girot Elizabeth A. , Goodman Benny , Ross Kath , Latter Sue , Jackson Dawn 
Published: February 2005

Background: Collaborative multi-site research is gaining recognition. In particular, across stakeholders in the health and social care professions, there has been an increase in the documentation of such approaches, with the majority acknowledging the strengths and few identifying the pitfalls. Four universities in the south west of England collaborated on the design, analysis and implementation of a project scoping the staff development needs of nursing and midwifery academics to meet the National Health Service Modernisation Agenda in the United Kingdom. Aim: This paper highlights the challenges and the lessons learned from each stage of the process of this large multi-site collaborative study. Consideration has been given to addressing the site-specific differences as well as the politics of the processes and power relations across the research team. Discussion: From an analytical reflection across the team, there were a number of lessons learned from the process of collaboration. Initially, the main challenge was the selection of the team and lead researcher and these were its greatest success. Nevertheless, managing each individual's competing roles within the organisation remained problematic. Particular challenges included gaining consensus on the research design, the chosen sample and data collection to reflect the site-specific differences and were overcome through discussion and effective leadership. Towards the end of the study, adequately representing each institution in the findings, as well as dissemination have remained the greatest challenges. Conclusions: While collaboration has been lauded as a way forward, this analysis of the process highlights some of the difficulties of working as a multi-site virtual team who are widely spread geographically and who have no previous connection. At different stages of the process there has been acknowledgement of the political dimensions affecting such an approach and a need to avoid the pitfalls of collaborative working in order to harness the potential of all team members, if success is to be achieved.
CLL, but not normal, B cells are dependent on autocrine VEGF and α4β1 integrin for chemokine-induced motility on and through endothelium
Authors: Till Kathleen J. , Spiller David G. , Harris Robert J. , Chen Haijuan , Zuzel Mirko , Cawley John C. 
Published: February 2005

AbstractVascular endothelial cell growth factor (VEGF) is a multifunctional cytokine involved in tumor formation. In chronic lymphocytic leukemia (CLL), it is known that the malignant cells secrete VEGF and possess VEGF receptors. This suggests that an autocrine loop might be important in the pathogenesis of CLL. Here we show that, in patients with lymphadenopathy, autocrine VEGF and α4β1 integrin are involved in the chemokine-dependent motility of CLL cells on and through endothelium—processes important for the invasion of lymphoreticular tissues, a major determinant of disease outcome. In contrast, normal lymphocytes were not dependent on autocrine VEGF or α4β1 for either type of cell movement. Moreover, in contrast to normal B lymphocytes, CLL cells failed to cluster and activate αLβ2 in response to chemokines, unless VEGF receptor(s) and α4β1 were also engaged by their respective ligands. This is the first demonstration that autocrine VEGF is involved in CLL-cell motility, and that the αLβ2 on the malignant cells is functionally altered compared with that of normal B cells in not undergoing activation in response to chemokine alone. Given the importance of cell motility for tissue invasion, the present results provide a rationale for a trial of VEGF and α4 blockade in patients with CLL who have tissue disease. (Blood. 2005;105:4813-4819)
Cyclooxygenase-2 (COX-2) is frequently expressed in multiple myeloma and is an independent predictor of poor outcome
Authors: Ladetto Marco , Vallet Sonia , Trojan Andreas , Dell'Aquila Maria , Monitillo Luigia , Rosato Rosalba , Santo Loredana , Drandi Daniela , Bertola Alessandra , Falco Patrizia , Cavallo Federica , Ricca Irene , De Marco Federica , Mantoan Barbara , Bode-Lesniewska Beata , Pagliano Gloria , Francese Roberto , Rocci Alberto , Astolfi Monica , Compagno Mara , Mariani Sara , Godio Laura , Marino Lydia , Ruggeri Marina , Omedè Paola , Palumbo Antonio , Boccadoro Mario 
Published: February 2005

AbstractCyclooxygenase 2 (COX-2) is an inflammation-associated enzyme involved in the pathogenesis of many solid tumors, but little is known about its presence and role in hematologic neoplasms. Multiple myeloma (MM) is known to involve a deregulated cytokine network with secretion of inflammatory mediators. We thus decided to investigate the involvement of COX-2 in this neoplasm. Western blotting (WB) was used to evaluate 142 bone marrow (BM) specimens, including MM and monoclonal gammopathy of undetermined significance (MGUS). Selected cases under-went further evaluation by WB on purified CD138+ cells, immunohistochemistry (IC), and real-time polymerase chain reaction (PCR) for mRNA expression. COX-2 was expressed in 11% (2 of 18) of MGUS specimens, 31% (29 of 94) of MM at diagnosis, and 47% (14 of 30) of MM with relapsed/refractory disease. COX-2 positivity was associated with a poor outcome in terms of progression-free (18 vs 36 months; P &lt; .001) and overall survival (28 vs 52 months; P &lt; .05). Real-time PCR showed COX-2 mRNA overexpression. IC and cell separation studies demonstrated COX-2 expression to be restricted to malignant plasma cells. This is the first report of the presence and prognostic role of COX-2 expression in MM. Future studies will assess COX-2 involvement in other hematologic tumors and its potential use as a therapeutic or chemo-preventive target in onco-hematology. (Blood. 2005; 105:4784-4791)
Conditional Expression of a Glucocorticoid Receptor Transgene in Thymocytes Reveals a Role for Thymic-Derived Glucocorticoids in Thymopoiesis in Vivo
Authors: Pazirandeh Ahmad , Jondal Mikael , Okret Sam 
Published: February 2005

AbstractWe and others have previously reported that thymic epithelial cells produce glucocorticoids (GCs). In vitro studies have also suggested that thymic-derived GCs play a role in the development of thymocytes. However, until now it has not yet been established whether thymic-derived GCs play a role in thymopoiesis in vivo. To investigate this, we conditionally overexpressed the GC receptor (GR) in thymocytes using transgenic mice with a tetracycline-inducible expression system. The influence of systemic GCs was excluded by adrenalectomizing the transgenic mice before the GR induction. Conditional expression of transgenic GR in the thymocytes of adrenalectomized transgenic mice led to a decrease in the thymocyte number. This was associated with increased thymocyte apoptosis. The effect of thymic-derived GCs on the thymocytes was confirmed after transgenic GR induction in a thymic organ culture system. Finally, the GR antagonist RU486 increased thymocyte number in adrenalectomized mice in vivo and prevented a reduction in thymocyte number in thymic organ culture after transgenic GR induction. These observations further confirmed a role for the thymic-derived GCs in regulating thymocyte homeostasis in vivo.
Dynamics of forward filtration combustion at the pore‐network level
Authors: Lu Chuan , Yortsos Yannis C. 
Published: February 2005

AbstractA pore‐network model is developed, based on a dual lattice, to study the dynamics of forward filtration combustion (FC) in porous media at the pore‐network scale. A novel moving coordinate method is also implemented that allows for the long‐term profiles to be obtained in a straightforward manner. The model is used to reproduce recent analytical work, including the multiplicity of steady states for the nonadiabatic case, and to study a number of other effects. Particular emphasis is placed on the effect of the heterogeneity in the microstructure, introduced by the randomness in the pore radius. It is found that the local disorder leads to less oxidant consumption, as compared to the homogeneous case. This underprediction increases with an increase in the disorder, a decrease in the thermal conductivity, and a decrease in the spatial correlation. Temporary local extinction can result for sufficiently large injection rates. As a result of the heterogeneity, the spatially averaged reaction rate is generally different from the rate calculated based on the microscale Arrhenius expression, using the averaged variables, with discrepancies of a factor of 2 or higher not uncommon. Although this effect depends on the parameter values, it can be a cause of concern when the fronts at the small scale are sufficiently distorted. Coupling of fronts occurs in a layered system, when there is sufficient oxidant supply. These results show that the microscale geometry can have a strong influence on the overall macroscopic behavior of the process. © 2005 American Institute of Chemical Engineers AIChE J, 2005
Composite sheets with biodegradable polymers and paper, the effect of paper strengthening agents on strength enhancement, and an evaluation of biodegradability
Authors: Kanie O. , Tanaka H. , Mayumi A. , Kitaoka T. , Wariishi H. 
Published: February 2005

AbstractComposite sheets composed of biodegradable polymers (BP) and paper were prepared, and their physical and biodegradable properties were investigated. The paper sheets were soaked in BP emulsions and cured at 100°C for 20 min. The wet strength of composite sheets with the same basis weight increased significantly with increasing BP content, although dry strength increased only moderately. A 0.5% addition of a common wet paper‐strengthening agent, poly(amidoamine‐epichlorohydrin) (PAE) resin, enhanced the wet strength, which reached 9.3 MPa, of composite sheets consisting of a BP : paper ratio of 20 : 80. Further enhancement was achieved by the addition of polyvinylamines (PVAm). The wet tensile strength of composite sheets consisting of BP and paper (20 : 80) increased by 27% with the addition of 0.2% PVAm and 0.5% PAE, whereas it was enhanced by only 3–4% with the addition of 0.7% PAE. The biodegradability of the composite sheets was somewhat retarded by the addition of PAE and PVAm. However, a 90% weight loss was observed 60 days after placing composite sheet samples in soil. A similar weight loss was observed after 45 days for composites without additives and after 30 days for base paper alone. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 861–866, 2005
Morphology of membranes formed by the isothermal precipitation of polyamide solutions from water/formic acid systems
Authors: Shih Chien‐Hsueh , Gryte Carl C. , Cheng Liao‐Ping 
Published: February 2005

AbstractMembranes were prepared by the direct and isothermal immersion of polyamide solutions in a formic acid/water bath. A crystalline polycaprolactam homopolymer, nylon 6, and a largely amorphous terpolymer of nylon 6, nylon 66, and nylon 610 were precipitated from solutions to form complex morphologies on the top and bottom surfaces and cross sections of the membranes. Terpolymer membranes exhibited the characteristics of a liquid–liquid phase‐separation process. According to the conditions of the solution and bath, nylon 6 precipitated to form membranes that showed dominance of crystallization or liquid–liquid phase separation. By precipitation from a solution containing a high concentration of a nonsolvent into a bath containing a high concentration of formic acid, skinless nylon 6 microporous membranes were formed. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 944–960, 2005
Current views of collagen degeradation. Progress towards understanding the resorption of connective tissues
Authors: Murphy Gillian , Reynolds John J. 
Published: February 2005

AbstractCollagen is the most abundant vertebrate protein and forms a stable fibrous architecture in connective tissues, such as bone, cartilage, skin and tendon. Much recent research has been directed towards an understanding of the molecular and cellular mechanisms involved in the synthesis and degradation of collagen, because a change in the normal balance, or an increased destruction of collagen, can cause loss of function of specialized tissues. This short review attempts to summarize present knowledge about the proteolytic destruction of collagen and the exciting new work on the factors that are emerging as important controlling agents. An understanding of the regulatory processes is yielding some important clues regarding the levels at which they can fail in pathological conditions and we speculate about evolving strategies for preventing uncontrolled resorption.
The role of growth factors in haemopoiesis
Authors: Dexter T. M. , Heyworth C. , Whetton A. D. 
Published: February 2005

AbstractMany of the haemopoietic cell growth factors have now been purified to homogeneity and their structural genes cloned. Methods are also now available for obtaining pure populations of haemopoietic cells. The use of such cells, in combination with pure growth factors, has provided intriguing information about the biological activities and mode of action of the factors in faciliating survival, proliferation and differentiation of the haemopoietic cells.
Chloroplast DNA and molecular phylogeny
Authors: Palmer Jeffrey D. 
Published: February 2005

AbstractThe small, relatively constant size and conservative evolution of chloroplast DNA (cpDNA) make it an ideal molecule for tracing the evolutionary history of plant species. At lower taxonomic levels, cpDNA variation is easily and conveniently assayed by comparing restriction patterns and maps, while at higher taxonomic levels, DNA sequencing and inversion analysis are the methods of choice for comparing chloroplast genomes. The study of cpDNA variation has already yielded important new insights into the origin and evolution of many agriculturally important crop plants, and promises to significantly enhance our phylogenetic understanding of the major lines of descent among land plants and algae.
The cellular and molecular basis of the Lyt‐1+2− T cell‐mediated tumor‐eradicating mechanism in vivo
Authors: Fujiwara Hiromi , Hamaoka Toshiyuki 
Published: February 2005

AbstractThis article reviews recent findings that bear on the mechanism(s) of tumor‐specific Lyt‐1+2− T cell‐mediated tumor eradication in vivo A tumor‐immune Lyt‐1+2− T cell subset has been identified which is distinct from T cells mediating in vitro cytotoxicity (Lyt‐1+2+/1−2+). The Lyt‐1+2− cells have a crucial role in rejecting tumor cells when adoptively transferred into T cell‐deprived B cell mice. This indicates that Lyt‐1+2− T cells do not necessarily require recruitment of the host's cytotoxic T cell precursors for implementation of in vivo immunity. Instead, this T cell subset exerts its anti‐tumor effect in collaboration with macrophages as shown with an in vivo tumor cell culture system utilizing a diffusion chamber. A pathway of Lyt‐1+2− T cell‐macrophage interaction leading to tumor cell killing is discussed in terms of its probable relevance to the eradication of tumor cell masses consisting of tumor cells expressing quantitatively and/or qualitatively different tumor antigens.
Roots: The discovery of chloroplast DNA
Authors: Kirk John T. O. 
Published: February 2005

AbstractIn the space of three years–from 1962 to 1964 – the proposition that chloroplasts contain their own DNA made the transition from being a controversial hypothesis to an accepted dogma. The crucial evidence came from biochemical analyses of the organelles themselves and from cytological studies. These discoveries revolutionized our views on the distribution of genetic information within the cell, and gave rise to the vigorous new field of chloroplast molecular biology. It is nevertheless ironic to recall that of the biochemical papers published on this topic in 1962–64, the one which was probably the most influential in creating the new paradigm was in fact quite wrong, and attributed to the chloroplast, DNA species which did not in reality belong to this organelle at all.