The dynamics of circular saw blades

This paper presents a review of the state of knowledge concerning the vibrational response characteristic of circular saw as used in the wood cutting industry. Analytical and experimental results are presented and some of the current research problems associated with supercritical speed operation are identified.     

Implications of socio-cultural contexts for the ethics of clinical trials

BACKGROUND: Health technology assesment (HTA) requires scientifically rigorous experimentation involving patients as subjects. HTA itself is required so that treatment given to patients will be both effective and efficient; this requirement is itself ethical in nature. At the same time it is essential that the methods used in HTA are ethically sound. Most healthcare researchers agree that the most effective and soundest method for assessing treatments is the randomised controlled trial (RCT). However, some researchers believe that the RCT is unethical, either in essence, or for use in some forms of medical research and HTA. Furthermore, many patients seem unable to understand the principles and purposes of the RCT, a factor which is highly detrimental for the validity of informed consent. Informed consent is the key to the ethics of medical research, both in most theories and in all codes of research conduct. Many RCTs therefore risk being unethical in practice, even if ethical in principle. AIM OF REPORT: To survey the main objections to the RCT and its alternatives. To assess the philosophical and methodological basis of these objections, and of the methods recommended for addressing them. To identify areas where objections are founded in social or cultural factors normally overlooked in ethical argument about the RCT methodology. To identify alternative arguments or methods which might resolve ethical conflicts in this area. HOW THE RESEARCH WAS CONDUCTED: The methods used were adapted from systematic reviews in medicine. Systematic searches of Medline, Psychlit and Sociofile CD-ROM databases; hand-searches of the major journals in general medicine and surgery, medical ethics and philosophy; and searches of books were carried out. The literature survey was restricted to articles published or abstracted in English. A database of the most relevant and useful materials was compiled, and is accessible on the Internet (http://www.liv.ac.uk/sdthomps/page1.html). RESEARCH FINDINGS: UNDERSTANDING RCTS AND THEIR ALTERNATIVES: There is some evidence of difficulty in understanding the aims and methods of RCTs, and some disquiet about elements of the RCT methodologies. These objections are well known and much discussed, and concern the use of placebo, the continuation of trials after significant differentials in benefit or harm are apparent, and randomisation. CULTURAL OR RELIGIOUS OBJECTIONS: There was an absence of evidence of cultural or religious objections to randomisation, placebo or other kinds of controlled prospective trials. This most likely reflects an absence of research rather than absence of objections. (ABSTRACT TRUNCATED)     

Th1-like cytokine production profile and individual specific alterations in TCRBV-gene usage of T cells from newly diagnosed type 1 diabetes patients after stimulation with beta-cell antigens

Thirty complete coding sequences of human major histocompatibility complex (Mhc) class II DRB alleles, spanning 237 codons, were analyzed for phylogenetic information using distance, parsimony, and likelihood approaches. Allelic genealogies derived from different parts of the coding sequence (exon 2, the 5' and 3' ends of exon 2, respectively, and exons 3-6) were compared. Contrary to prior assertions, a rigorous analysis of allelic genealogies in this gene family cannot be used to justify the claim that the lineage leading to modern humans contained on average at least 100,000 individuals. Phylogenetic inferences based upon the exon 2 region of the DRB loci are complicated by selection and recombination, so this part of the gene does not provide a complete and accurate view of allelic relationships. Attempts to reconstruct human history from genetic data must use realistic models which consider the complicating factors of nonequilibrium populations, recombination, and different patterns of selection.     

Prevention of remote organ injury in cardiopulmonary bypass: the impact of flow generation technique

The purpose of this study was to investigate the effects of 3 different types of flow generation for cardiopulmonary bypass on gastrointestinal permeability and on neutrophil expression of CD11b, a surface marker of neutrophil activation. Fourteen patients undergoing elective coronary revascularization were selected randomly to receive 1 of the 3 flow generation techniques (roller, pulsatile, or centrifugal). Intestinal permeability was assessed by the fraction of an oral dose of 51chromium-ethylenediaminetetraacetate (51Cr-EDTA) recovered in the urine over 24 h. Neutrophil activation was determined by expression of CD11b markers at 6 time points. Overall, the 14 patients showed significant increases in intestinal permeability. It was not possible to demonstrate statistically significant differences among the flow generation groups; however, when compared to both roller pump groups, the centrifugal pump group showed a 3.2% reduction in intestinal permeability. There was no change in the expression of CD11b receptors throughout the time points, nor was there a relationship of CD11b markers to the flow generation technique.     

Acoustic emission monitoring of ZB-1 intermediate scale vessel test

A program to develop the use of acoustic emission (AE) flaw detection methods for continuous surveillance of reactor pressure boundaries is in process in the United States. Evaluation of laboratory developed relationships for data verification and interpretation was performed by participation in a German intermediate scale vessel (ZB-1) test. The test sequence consisted of repeated blocks of a hydrostatic test followed by two sets of cyclic loading at different R-ratios. Testing was performed in cooperation with the German Materialprüfungsanstalt at the Grosskraftwerk facility in Mannheim, West Germany. This paper discusses preliminary results obtained during the first half of the test which was performed at 70°C. The AE system detected crack growth from machined flaws and also spontaneous crack growth in a fabrication weld. AE signals from cracking were consistently high amplitude and occurred at or near peak load. Crack growth rates estimated from AE data were consistent with values derived from crackopening-displacement gauges. The test produced unique and important data needed to develop reliable application of AE methods for continuous monitoring of reactor pressure systems.     

Shot planning and analysis tools on the NIF project

Shot planning and analysis tools (SPLAT) integrate components necessary to help achieve a high over-all operational efficiency of the National Ignition Facility (NIF) by combining near and long-term shot planning, final optics demand and supply loops, target diagnostics planning, and target fabrication requirements. Currently, the SPLAT project is comprised of two primary tool suites for shot planning and optics demand. The shot planning component provides a web-based interface to selecting and building a sequence of proposed shots for the NIF. These shot sequences, or “lanes” as they are referred to by shot planners, provide for planning both near-term shots in the Facility and long-term “campaigns” in the months and years to come. The shot planning capabilities integrate with the Campaign Management Tool (CMT) for experiment details and the NIF calendar for availability. Future enhancements will additionally integrate with target diagnostics planning and target fabrication requirements tools. The optics demand component is built upon predictive modeling of maintenance requirements on the final optics as a result of the proposed shots assembled during shot planning. The predictive models integrate energetics from a Laser Performance Operations Model (LPOM), the status of the deployed optics as provided by the online Final Optics Inspection system, and physics-based mathematical “rules” that predict optic flaw growth and new flaw initiations. These models are then run on an analytical cluster comprised of forty-eight Linux-based compute nodes. Results from the predictive models are used to produce decision-support reports in the areas of optics inspection planning, optics maintenance exchanges, and optics beam blocker placement advisories. Over time, the SPLAT project will evolve to provide a variety of decision-support and operation optimization tools.     

Experiment archive,analysis, and visualization at the National Ignition Facility

The National Ignition Facility (NIF) at the Lawrence Livermore National Laboratory is the world's most energetic laser, providing a scientific research center to study inertial confinement fusion and matter at extreme energy densities and pressures. A target shot involves over 30 specialized diagnostics measuring critical x-ray, optical and nuclear phenomena to quantify ignition results for comparison with computational models. The Shot Analysis and Visualization System (SAVI) acquires and analyzes target diagnostic data for display within a time-budget of 30 min. Laser and target diagnostic data are automatically loaded into the NIF archive database through clustered software data collection agents. The SAVI Analysis Engine distributes signal and image processing tasks to a Linux cluster where computation is performed. Intermediate results are archived at each step of the analysis pipeline. Data is archived with metadata and pedigree. Experiment results are visualized through a web-based user interface in interactive dashboards tailored to single or multiple shot perspectives. The SAVI system integrates open-source software, commercial workflow tools, relational database and messaging technologies into a service-oriented and distributed software architecture that is highly parallel, scalable, and flexible. The architecture and functionality of the SAVI system will be presented along with examples.