bluuebunny/crossref_metadata_2025_split huggingface dataset:
Toxicity of perfluorooctane sulfonate and perfluorooctanoic acid to plants and aquatic invertebrates
Authors: Li Mei‐Hui 
Published: May 2008

AbstractAcute toxicities of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were tested on four freshwater species and three plant species. PFOS was more toxic than PFOA for all species tested in this study. Similar time‐response patterns of PFOS and PFOA toxicity were observed for each tested species. Values of the 48‐h LC50 of PFOS for all test species ranged from 27 to 233 mg/L and values of the 96‐h LC50 for three of the species ranged from 10 to 178 mg/L. Values of the 48‐h LC50 of PFOA for all test species ranged from 181 to 732 mg/L and values of the 96‐h LC50 for three of the species ranged from 337 to 672 mg/L. The most sensitive freshwater species to PFOS was green neon shrimp (Neocaridina denticulate) with a 96‐h LC50 of 10 mg/L. Of the aquatic organisms tested, the aquatic snail (Physa acuta) always has the highest resistance to PFOS or PFOA toxicity over each exposure period. Both PFOS and PFOA had no obvious adverse effect on seed germination for all three plant species. Five‐day EC50 of root elongation was more sensitive to LC50 of seed germination in this study. Based on EC10, EC50, and NOECs, the 5‐day root elongation sensitivity of test plants to both PFOS and PFOA was in the order of lettuce (Lactuca sativa) > pakchoi (Brassica rapa chinensis) > cucumber (Cucumis sativus). Based on the results of this study and other published literature, it is suggested that current PFOS and PFOA levels in freshwater may have no acute harmful ecological impact on the aquatic environment. However, more research on the long‐term ecological effects of PFOS and PFOA on aquatic fauna are needed to provide important information to adequately assess ecological risk of PFOS and PFOA. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.
Cognitive radio adaptation using particle swarm optimization
Authors: Zhao Zhijin , Xu Shiyu , Zheng Shilian , Shang Junna 
Published: May 2008

AbstractOne of the basic capabilities of cognitive radio is to adapt the radio parameters according to the changing environment and user needs. This paper proposes a new adaptation method which uses particle swarm optimization (PSO) to optimize cognitive radio parameters given a set of objectives. The procedure of the proposed method is presented and multicarrier system is used for simulation analysis. Experimental results show that the proposed method performs far better than genetic algorithm (GA)‐based adaptation method in terms of convergence speed, converged fitness values, and stability. The proposed method can also provide the tradeoffs of the objective functions, and the resulting parameter configuration is consistent with the weights of the objective functions. Copyright © 2008 John Wiley & Sons, Ltd.
The application of flash-over switch in high energy fluence diode
Authors: Zhang Yongmin , Tang Junping , Huang Jianjun , Qiu Aici , Guan Zhicheng , Wang Xinxin 
Published: May 2008

AbstractIn order to restrain the prepulse of a high energy fluence diode, a flash-over switch made of a nylon cylinder was inserted in between the cathode stalk and the cathode. Secondary prepulse technique was developed to lower the flash-over voltage of the switch. It was found that the surface resistivity of the nylon insulator changes considerably after each shot and this resistivity on the order of 107 Ω/m is most suitable for a 20-mm long flash-over switch to operate stably at a lower flash-over voltage.
Investigations on low temperature laser-generated plasmas
Authors: Caridi F. , Torrisi L. , Margarone D. , Borrielli A. 
Published: May 2008

AbstractA nanosecond pulsed Nd-Yag laser, operating at an intensity of about 109 W/cm2, was employed to irradiate different metallic solid targets (Al, Cu, Ta, W, and Au) in vacuum. The measured ablation yield increases with the direct current (dc) electrical conductivity of the irradiated target. The produced plasma was characterized in terms of thermal and Coulomb interaction evaluating the ion temperature and the ion acceleration voltage developed in the non-equilibrium plasma core. The particles emission produced along the normal to the target surface was investigated measuring the neutral and the ion energy distributions and fitting the experimental data with the “Coulomb-Boltzmann-shifted” function. Results indicate that the mean energy of the distributions and the equivalent ion acceleration voltage of the non-equilibrium plasma increase with the free electron density of the irradiated element.
Force-closure analysis of 6-DOF cable manipulators with seven or more cables
Authors: Diao Xiumin , Ma Ou 
Published: May 2008

SUMMARYA cable manipulator controls its end-effector by a number of cables. If the cables can balance any external and inertia wrenches at a certain pose of the end-effector, the cable manipulator is said to have a force-closure at this pose. Since a cable can work only in tension, the force-closure at a specific pose may not exist. Thus, how to check the existence of force-closure at a given pose is an important issue for design and control of cable manipulators. This paper describes a systematic method of verifying the existence of force-closure at a specific pose of a general 6-DOF cable manipulator with seven or more cables. By examining the Jacobian matrix of the manipulator, the method can determine whether a force-closure exists at the pose corresponding to the Jacobian matrix. The necessity and sufficiency of the proposed method are mathematically proven. Moreover, a convex-analysis-based simplification of the method for manipulators with more than seven cables is also discussed.
A hand–eye calibration algorithm based on screw motions
Authors: Zhao Zijian , Liu Yuncai 
Published: May 2008

SUMMARYWhen computer vision technique is used in robotics, robotic hand–eye calibration is a very important research task. Many algorithms have been proposed for hand–eye calibration. Based on these algorithms, we introduce a new hand–eye calibration algorithm in this paper, which employs the screw motion theory to establish a hand–eye matrix equation by using quaternion and gets a simultaneous result for rotation and translation by solving linear equations. The algorithm proposed in this paper has high accuracy and stable computational efficiency and can be understood easily. Both simulations and real experiments show the superiority of our algorithm over the comparative algorithms.
LITERATURE SEARCHING FOR RANDOMIZED CONTROLLED TRIALS USED IN COCHRANE REVIEWS: RAPID VERSUS EXHAUSTIVE SEARCHES
Authors: Royle Pamela , Milne Ruairidh 
Published: May 2008

Objectives:To analyze sources searched in Cochrane reviews, to determine the proportion of trials included in reviews that are indexed in major databases, and to compare the quality of these trials with those from other sources.Methods:All new systematic reviews in the Cochrane Library, Issue1 2001, that were restricted to randomized controlled trials (RCTs) or quasi-RCTs were selected. The sources searched in the reviews were recorded, and the trials included were checked to see whether they were indexed in four major databases. Trials not indexed were checked to determine how they could be identified. The quality of trials found in major databases was compared with those found from other sources.Results:The range in the number of databases searched per review ranged between one and twenty-seven. The proportion of the trials in the four databases were Cochrane Controlled Trials Register=78.5%, MEDLINE=68.8%, Embase=65.0%, and Science/Social Sciences Citation Index=60.7%. Searching another twenty-six databases after Cochrane Controlled Trials Register (CCTR), MEDLINE, and Embase only found 2.4% additional trials. There was no significant difference between trials found in the CCTR, MEDLINE, and Embase compared with other trials, with respect to adequate allocation concealment or sample size.Conclusions:There was a large variation between reviews in the exhaustiveness of the literature searches. CCTR was the single best source of RCTs. Additional database searching retrieved only a small percentage of extra trials. Contacting authors and manufacturers to find unpublished trials appeared to be a more effective method of obtaining the additional better quality trials.
ILLUSTRATIVE ESTIMATES OF COSTS AND EFFECTS OF THE USE OF DOPPLER ULTRASONOGRAPHY IN HIGH-RISK PREGNANCIES
Authors: Westergaard Hanne Brix , Sørensen Jan , Langhoff-Roos Jens 
Published: May 2008

Objectives: To examine the cost-effectiveness of Doppler ultrasonography in high-risk pregnancies.Methods: An analysis was made of the cost-effectiveness of Doppler ultrasonography in high-risk pregnancies in relation to different organizational models. National costs of Doppler ultrasonography for singleton pregnancies with intrauterine growth retardation were estimated for three models. The cost-effectiveness analysis was based on results from a meta-analysis on clinical effects, patient costs, immediate health care costs, and costs per “saved” perinatal death.Results: In the decentralized model (the current situation in Denmark), incremental health care costs were estimated to be 13.5 million DKK, with patient costs set at zero. In the regional and centralized models, the estimated costs were 9.3 million/0.9 million DKK and 3.4 million/2.6 million DKK, respectively. The incremental costs were more than outweighed by the savings made from significant reductions in obstetric interventions. The centralized model dominated the other two models in the cost-effective analysis. In the decentralized model, the costs of avoiding one perinatal death were estimated to be 1 million DKK. The sensitivity analysis suggested that the cost-effectiveness ratio differed considerably, depending on the assumptions used, although the rank order of the three models did not change.Conclusions: The cost-effectiveness analysis showed that a centralized model with five obstetric centers offering Doppler ultrasonography dominates the regional and decentralized models. However, even with the decentralized model (which reflects the current situation in Denmark), the costs of avoiding one perinatal death would seem to be reasonable. In view of the paucity of available cost and effects data and the sensitivity of the results to changes in the assumptions made, more reliable information is needed before a decision can be made regarding the organization of Doppler ultrasonography for high-risk pregnancies.
APPLICATION OF A DIAGNOSTIC DECISION RULE IN CHILDREN WITH MENINGEAL SIGNS: A COST-MINIMIZATION STUDY
Authors: Oostenbrink Rianne , Oostenbrink Jan B. , Moons Karel G. M. , Derksen-Lubsen Gerarda , Grobbee Diederick E. , Redekop W. Ken , Moll Henriëtte A. 
Published: May 2008

Objectives: Recently, we developed a diagnostic rule for the diagnosis and treatment of children with meningeal signs. This rule may provide the physician with a rationale to decide on the use of diagnostic and treatment procedures in these children and to improve their care. In this study, we estimated cost savings of the rule compared with current practice.Methods: Routine care data of 360 children visiting the emergency department of the Sophia Children's Hospital with meningeal signs between 1988 and 1998 were used. Costs of diagnostic tests and treatment were estimated by using financial accounts of an academic and a general pediatric hospital. The number of procedures actually performed and the resulting cost estimates (i.e. unit costs×volume) were compared with the estimated figures after application of the decision rule.Results: The population of children with meningeal signs comprised 99 with bacterial meningitis (27%), 36 with another serious bacterial infection (10%), and 225 with a self-limiting disease (63%). Application of the rule would reduce lumbar punctures by 12% and hospitalizations for empirical treatment by 15% with the same diagnostic accuracy as current practice. Cost savings were estimated at €292 per patient (relative reduction 10%) and were mainly achieved in the treatment course (€259).Conclusions: A diagnostic decision rule for children with meningeal signs has the potential to improve the appropriate use of medical resources, to be cost-effective, and to ascertain the absence of bacterial meningitis earlier.
COST-EFFECTIVENESS OF ADJUNCTIVE HYPERBARIC OXYGEN IN THE TREATMENT OF DIABETIC ULCERS
Authors: Guo Shien , Counte Michael A. , Gillespie Kathleen N. , Schmitz Homer 
Published: May 2008

Objectives:This study estimates the cost-effectiveness (CE) of the adjunctive use of hyperbaric oxygen (HBO2) therapy in the treatment of diabetic ulcers based on the payer's and societal perspectives.Methods:The study population was a hypothetical cohort of 1,000 patients sixty years of age with severe diabetic foot ulcers. A decision tree model was constructed to estimate the CE of HBO2 therapy in the treatment of diabetic ulcers at years 1, 5, and 12. Scenario and one-way sensitivity analyses were also undertaken to identify parameters that may significantly influence the estimates.Results:The CE model estimated that the incremental cost per additional quality-adjusted life year (QALY) gained at years 1, 5, and 12, was $27,310, $5,166, and $2,255, respectively.Conclusions:The study results indicate that HBO2 therapy in the treatment of diabetic ulcers is cost-effective, particularly based on a long-term perspective. However, the results are limited by the clinical studies that provide the basis of the CE estimation.
The usefulness of the NHS Economic Evaluation Database to researchers undertaking technology assessment reviews
Authors: Nixon John , Duffy Steven , Armstrong Nigel , Craig Dawn , Glanville Julie , Christie James , Drummond Michael , Kleijnen Jos 
Published: May 2008

Objectives:Health-care technology reviews now increasingly include outcome costs as well as clinical effects. This study reports the findings and implications of a survey to explore the usefulness of the National Health Service Economic Evaluation Database (NHS EED) within this process.Methods:Postal survey of lead authors of Technology Assessment Reviews (TARs) commissioned by the United Kingdom's National Institute for Clinical Excellence (NICE). The questionnaire investigated the usefulness of NHS EED in terms of (a)search strategy, (b)data extraction, (c)quality assessment, and (d)determining requirementsfornew modeling studies. Qualitative data were requested, including opinions regarding NHS EED.Results:NHS EED was used in 90 percent of all identified reviews (n=46). The questionnaire response rate was 63 percent. The percentage of scores 3 or above (most useful), 2 or below (least useful), or N/A were, respectively, (a)search strategy=62 percent, 23 percent, 15 percent; (b)data extraction=23 percent, 27 percent, 50 percent; (c)quality assessment=38 percent, 19 percent, 42 percent; (d)determining requirements for new modeling studies=27 percent, 23 percent, 50 percent. The results were expanded further in the qualitative data from the respondents.Conclusions:NHS EED is a useful tool for a variety of tasks in the NICE/TAR process but not, unsurprisingly, as a replacement for understanding primary studies. There is, however, a need to reduce the impact of time lags between the publication of economic evaluations and the appearance of abstracts relating to them on NHS EED. The results will inform future developments of the NHS EED database, which should increase its usefulness to researchers.
Cost-effectiveness of reduction mammaplasty
Authors: Taylor Andrew J. , Tate David , Brandberg Yvonne , Blomqvist Lennart 
Published: May 2008

Objectives:The purpose of this study is to provide a comparison of the benefits of reduction mammaplasty (RM) for women with heavy breasts often termed macromastia or breast hypertrophy (BH) surgery. The rationale is to provide information to allow decision-makers to make judgments about the cost-effectiveness of this intervention and make comparisons with other interventions which are commonly undertaken within publicly financed health-care systems.Methods:Data from a previous outcomes study in Sweden is re-analyzed to derive quality of life measures, from which a mean level of benefit outcome is derived and a cost per quality-adjusted life year is calculated (cost per QALY).Results:The low Cost per QALY suggests that reduction mammaplasty is cost-effective when compared with other treatments which are commonly undertaken.Conclusions:The authors suggest that the evidence in favor of funding reduction mammaplasty is strong and that decision-makers review their policy in light of this new evidence.
Assessing the economics of vaccination forNeisseria meningitidisin industrialized nations: A review and recommendations for further research
Authors: Getsios Denis , Caro Ingrid , El-Hadi Wissam , Caro Jaime J. 
Published: May 2008

Objectives:To review the existing health economic literature on meningococcal disease vaccination.Methods:A Medline search for economic evaluations of vaccination programs for meningococcal disease in developed countries was conducted. All identified studies were reviewed.Results:Nine published studies were identified examining either mass vaccination during outbreaks or routine vaccination. Although net expenses were estimated in almost all studies, the resulting cost-effectiveness ratios varied widely. Vaccination of college-age students was found to be potentially cost-effective in Australia but not in the United States. With one exception, routine vaccination of children and adolescents in Europe was predicted to be cost-effective. Many simplifying assumptions were made, and important elements were often left out, in particular the potential for reduced transmission of disease.Conclusions:The methods used and the vaccination strategies vary widely, and results do not provide strong grounds for making conclusions as to whether vaccination is cost-effective. Furthermore, in all instances, transmission of disease, changes in population carriage rates, and outbreaks are either ignored, dealt with using very broad simplifying assumptions, or are not necessarily generalizable to other settings. The analyses provide some insight into the potential cost-effectiveness of vaccination, but more importantly, they highlight areas requiring further study. Economic evaluations based on observed outcomes from recently implemented strategies would be helpful, as would more sophisticated health economic models. The choice of vaccination strategies cannot be based on the results of existing economic analyses.
Redefining health technology assessment in Canada: Diversification of products and contextualization of findings
Authors: Lehoux Pascale , Tailliez Stéphanie , Denis Jean-Louis , Hivon Myriam 
Published: May 2008

Objectives:While strategies for enhancing the dissemination and impact of Health Technology Assessment (HTA) are now being increasingly examined, the characteristics of HTA production have received less attention.Methods:This study presents the results of a content analysis of the HTA documents (n=187) produced by six Canadian agencies from 1995 to 2001, supplemented by interviews with chief executive officers and researchers (n=40). The goal of this analysis was to characterize the agencies' portfolios and to analyze the challenges these agencies face in responding to the increased demand for HTA.Results:On average, thirty HTA products were issued annually by the agencies. While the bulk of documents produced were full HTA reports (76 percent), two agencies showed significant diversification in their products. Three agencies in particular actively supported the publication of results in scientific journals. Three agencies showed evidence of adapting to different institutional environments by specializing in certain areas (drugs, health services). Overall, a significant portion of the agencies' HTAs contained data on costs (37 percent) and effectiveness (48 percent), whereas ethical and social issues were rarely addressed (17 percent). Most agencies addressed issues and outcomes that did not strictly fall under the typical definition of HTA but that increased the “contextualization” of their findings.Conclusions:Our discussion highlights four paradoxes and reflects further on challenges raised by the coordination of HTA within large countries and among European states. This study concludes that HTA is being redefined in Canada as HTA agencies offer a more contextualized informational basis, an approach that may prove more compatible with the increased demand for HTA.
Factors influencing the publication of health research
Authors: Cronin Eugenia , Sheldon Trevor 
Published: May 2008

Objectives:Assess the degree to which research project findings were published and explore factors that influenced publication.Methods:Questionnaire to project leaders. Classification of publications and findings. Chi-squared; univariate and multivariate Cox regression analyses.Results:Forty percent of projects published in peer-reviewed journal; highly statistically significant relationships between publication in peer-reviewed journals and (1) projects in Responsive/Fellowships streams (p=.045); and (2) projects awarded >£22,713 (p=.02); influence of study findings not statistically significant.Conclusions:Funders should consider the significant number of studies that did not result in publication and the higher rate of publication in peer-reviewed journals from some programs.
Use of systematic reviews in the development of new provincial public health policies in Ontario
Authors: Dobbins Maureen , Thomas Helen , O'Brien Mary Ann , Duggan Melissa 
Published: May 2008

Objectives: The study determined whether the results of recently completed systematic reviews evaluating the effectiveness of public health interventions were used in the development of new provincial policies for public health practice.Methods: This telephone survey included all members from five review groups who updated the Ontario Mandatory Health Programs and Services guidelines for Public Health in 2000. Independent variables included characteristics of the systematic reviews, organization, and the individual. Outcomes included the use of the reviews in developing new policies and the extent to which the reviews led to new recommendations for practice. Descriptive summaries as well as multiple linear regression were conducted.Results: Eighty-five percent of decision-makers agreed to participate in the study. Ninety-six percent of respondents reported that the systematic reviews played a part in developing the new guidelines, while 47 percent indicated that the reviews contributed a great deal to the development of new recommendations for practice. The multiple linear regression model explained 42 percent of the variation in use of the reviews for developing new recommendations for practice. Significant predictor variables included the importance of the reviews in comparison to other sources of information and relevance of the reviews to the policy decisions.Conclusion: Public health decision-makers in Ontario have very positive perceptions of the usefulness of systematic reviews in policy development. Therefore, ongoing efforts to promote the usefulness and relevance of systematic reviews to public health decision-makers should remain a priority for health services researchers.