Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Benchmark”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,747 records · Page 97Linked to original sources
PubMed2026

Structured robotic colorectal training in a non-tertiary NHS hospital: a 502-case consecutive cohort implementation study.

Robotic-assisted colorectal surgery has expanded rapidly across NHS practice in the UK. Structured unit-wide training pathways are essential for safe technology adoption, yet published outcome data from non-tertiary hospitals remain limited. This study describes the implementation and feasibility of a unit-wide robotic colorectal program at a high-volume non-tertiary hospital, reporting outcomes across 502 consecutive resections performed by eight consultant surgeons and presenting these in the context of nationally published benchmarks. A retrospective cohort study of 502 consecutive robotic colorectal resections performed at York Teaching Hospital between May 2022 and December 2025. Eight consultant surgeons (A-H) participated in a structured four-phase training pathway incorporating simulation training, proctored cases, complexity-based case progression, and formal credentialing. Primary outcomes were 30-day mortality, unplanned return to theatre (RTT), and anastomotic leak (AL). Anastomotic leak was calculated using only patients who underwent anastomosis as the denominator. Procedure-stratified and individual surgeon outcomes with 95% confidence intervals were reported. Risk-adjusted cumulative sum (RA-CUSUM) analysis was performed to evaluate learning curves. Outcomes are presented descriptively alongside nationally published reference data; no formal statistical comparison against national benchmarks was performed. 502 robotic colorectal resections were performed. Mean patient age was 70.0 ± 11.3 years; 58.4% were male. Median ASA grade was III. The indication was malignancy in 89.2% of cases. Length of stay was non-normally distributed and is therefore reported using median and interquartile range in the revised analysis. Key outcomes: - 30-day mortality: 1.0% (5/502; 95% CI 0.4-2.3%) - Unplanned return to theatre (RTT): 5.2% (26/502; 95% CI 3.6-7.5%) - Anastomotic leak (AL): 3.3% (15/450; 95% CI 2.0-5.5%; denominator = patients with anastomosis) - 30-day unplanned readmission: 5.0% (25/502; 95% CI 3.4-7.2%) - Conversion to open surgery: 3.6% (18/502; 95% CI 2.3-5.6%) - Lymph node yield ≥12: 91.3% of cancer resections - R0 resection rate: 95.1% of cancer resections All primary outcomes fell within or below the published reference ranges used for descriptive context. RA-CUSUM trajectories were heterogeneous: no surgeon crossed the predefined upper control limit, but several curves showed later upward movement. Accordingly, the analysis is interpreted as safety surveillance rather than evidence of uniform performance improvement. RA-CUSUM monitoring showed that no surgeon crossed the predefined upper control limit; however, heterogeneous trajectories precluded a claim of uniform performance improvement.

Humans↗
PubMed2003

Design of a surveillance system of antibiotic use and bacterial resistance in German intensive care units (SARI).

BACKGROUND: Data on antibiotic consumption and bacterial resistance are important for benchmarking, ensuring quality of antibiotic treatment and helping to understand the relationship between the use of antibiotics and the emergence of resistance. METHODS: The SARI project is an ecological study that has established laboratory-based surveillance in German intensive care units (ICU). Resistance rates of 13 sentinel pathogens are reported and certain alert organisms are sent for genotyping and retesting of antimicrobial resistance. RESULTS: The project, initiated in February 2000, now includes 35 ICUs generating a total of 266,013 patient days, 354,356 defined daily doses (DDD) and providing susceptibility data on 21,354 isolates. Pooled antibiotic usage density (AD = DDD/1,000 patient days) was highest for penicillins with lactamase inhibitor (AD 338.3) followed by quinolones (AD 155.5) and second-generation cephalosporins (AD 124.6). Total AD was calculated as 1,337 DDD/1,000 patient days. Resistance rates (RR) for laboratories testing according to the German Industrial Standard (DIN) were 19.3% for methicillin-resistant Staphylococcus aureus (MRSA), 9.5% for ciprofloxacin-resistant Escherichia coli and 25.4% for imipenem-resistant Pseudomonas aeruginosa. 40% of the laboratories did not identify the extended spectrum beta lactamase production of a Klebsiella pneumoniae strain. CONCLUSION: Focusing on German ICUs, the SARI surveillance system provides a concept that produces a benchmark for the link between antibiotic resistance and consumption.

Anti-Bacterial Agents↗
PubMed1992

Incidence of developmental defects at the no observed adverse effect level (NOAEL).

Bioassay data from Teratology, Vol. 1 (1968) through Vol. 40 (1990), were utilized which were sufficient to establish no observed adverse effect levels (NOAEL's) for 120 experiments on 93 developmental toxicants in animals. The observed incidence (risk) at the NOAEL was calculated as the proportion of affected fetuses minus the proportion affected in the control animals. This calculation did not require any dose-response modeling. Data were primarily from experiments on rats and mice with a few studies on rabbits and hamsters. There did not appear to be differences in risks at the NOAEL among these four species. For each experiment, the risk at the NOAEL was tabulated for all of the adverse effects which shared the same NOAEL. Since the observed risk at the NOAEL for either dead/resorbed or abnormal fetuses exceeded 1% in about one-fourth of the cases, this suggests that a benchmark dose with a risk on this order would eliminate the higher risks and serve as a basis for establishing reference doses. If the lower confidence limit on a benchmark dose is used in place of the NOAEL, better experimental designs with more animals would result in tighter confidence limits, giving larger (less stringent) reference doses than poorer experiments.

Abnormalities, Drug-Induced↗
PubMed1995

Negative selection in hepatic tumor promotion in relation to cancer risk assessment.

Mechanistic studies with phenobarbital (PB), 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD) and other liver tumor promoters support a general model of promotion involving negative selection where specifically-mutated cells derive a growth advantage in the presence of persistent mitosuppression. Exposure to these liver tumor promoters appears to transiently enhance hepatocyte replication, presumably via transcriptional activation of growth regulatory genes, leading to a homeostatic increase in mitoinhibitory growth factors in the liver to constrain proliferation. Transforming growth factor beta 1 (TGF-beta), a potent mitoinhibitory growth factor for hepatocytes, has been associated with the mitosuppression caused by PB and certain peroxisomal proliferators. Escape from TGF-beta mitosuppression may involve loss or alteration of function of the mannose 6-phosphate/insulin-like growth factor II (M6P/IGFII) receptor, which is required for TGF-beta 1 activation, or alterations of the TGF-beta types I, II and III signal transduction receptors. A risk assessment based on a negative selection mechanism could be conducted for tumor promotion endpoints with TCDD and compared with current approaches that implicitly regard TCDD as an initiator. Benchmark dose calculation using centrilobular induction of cytochromes P450 1A1 and 1A2 as a surrogate for periportal growth stimulation would provide a rational starting point for application of conventional safety factor approaches, similar to those used with non-cancer effects. In the future, tissue and plasma concentrations of specific growth factors, e.g. TGF-beta or hepatocyte growth factor, HGF, might be considered as more direct dose surrogates for tumor-promoting effects of xenobiotics. Uncertainty factor adjustments to a TCDD benchmark dose calculation should eventually rely on direct knowledge of regulation of specific growth regulatory genes and their receptors in relevant species and on species differences in TCDD pharmacokinetics, instead of application of default animal-to-human and interindividual uncertainty factors.

Animals↗
PubMedDate not supplied

Lunar transportation scenarios utilising the Space Elevator.

The Space Elevator (SE) concept has begun to receive an increasing amount of attention within the space community over the past couple of years and is no longer widely dismissed as pure science fiction. In light of the renewed interest in a, possibly sustained, human presence on the Moon and the fact that transportation and logistics form the bottleneck of many conceivable lunar missions, it is interesting to investigate what role the SE could eventually play in implementing an efficient Earth to Moon transportation system. The elevator allows vehicles to ascend from Earth and be injected into a trans-lunar trajectory without the use of chemical thrusters, thus eliminating gravity loss, aerodynamic loss and the need of high thrust multistage launch systems. Such a system therefore promises substantial savings of propellant and structural mass and could greatly increase the efficiency of Earth to Moon transportation. This paper analyzes different elevator-based trans-lunar transportation scenarios and characterizes them in terms of a number of benchmark figures. The transportation scenarios include direct elevator-launched trans-lunar trajectories, elevator launched trajectories via L1 and L2, as well as launch from an Earth-based elevator and subsequent rendezvous with lunar elevators placed either on the near or on the far side of the Moon. The benchmark figures by which the different transfer options are characterized and evaluated include release radius (RR), required delta v, transfer times as well as other factors such as accessibility of different lunar latitudes, frequency of launch opportunities and mission complexity. The performances of the different lunar transfer options are compared with each other as well as with the performance of conventional mission concepts, represented by Apollo.

Earth, Planet↗
PubMed2006

Rationale for establishing regional ST-elevation myocardial infarction receiving center (SRC) networks.

Recent developments have provided a unique opportunity for the organization of regional ST-elevation myocardial infarction (STEMI) receiving center (SRC) networks. Because cumulative evidence has demonstrated that rapid primary percutaneous coronary intervention (PCI) is the most effective reperfusion strategy for acute STEMI, the development of integrated SRC networks could extend the benefits of primary PCI to a much larger segment of the US population. Factors that favor the development of regional SRC networks include results from recently published clinical trials, insight into contemporary STEMI treatment patterns from observational registries, experience with the nation's current trauma system, and technological advances. In addition, the 2004 American College of Cardiology/American Heart Association STEMI guidelines have specified that optimal "first medical contact-to-balloon" times should be <90 minutes, so a clear benchmark for timely reperfusion has been established. Achievement of this benchmark will require improvements in the current process of care as well as increased multidisciplinary cooperation between emergency medical services, emergency medicine physicians, and cardiologists. Two types of regional SRC networks have already begun to evolve in role-model cities, including prehospital cardiac triage and interhospital transfer. Regional coordination of SRC networks is needed to ensure quality monitoring and to delineate the ideal reperfusion strategy for a given community based on available resources and expertise.

Angioplasty, Balloon, Coronary↗
PubMed2006

Assessing prevention research impact: a bibliometric analysis.

BACKGROUND: This study was undertaken to explore a bibliometric approach to assessing the impact of selected prevention research center (PRC) peer-reviewed publications. METHODS: The 25 eligible PRCs were asked to submit 15 papers that they considered the most important to be published in the decade 1994-2004. Journal articles (n=227) were verified in 2004 and categorized: 73% were research reports, 10% discussion articles, 9% dissemination articles, and 7% review articles. RESULTS: Only 189 articles (83%) were searchable via the Institute of Scientific Information (ISI) Web of Science databases for citation tracking in 2004. These 189 articles were published in 76 distinct journals and subsequently cited 4628 times (range 0 to 1523) in 1013 journals. Articles published before 2001 were cited a median of 14 times each. Publishing journals had a median ISI impact factor of 2.6, and ISI half-life of 7.2. No suitable benchmarks were available for comparison. The PRC influence factor (number of PRCs that considered a journal highly influential) was only weakly correlated with the ISI impact factor and was not correlated with half-life. CONCLUSIONS: Conventional bibliometric analysis to assess the scientific impact of public health prevention research is feasible, but of limited utility because of omissions from ISI's databases, and because citation benchmarks for prevention research have not been established: these problems can and should be addressed. Assessment of impact on public health practice, policy, or on the health of populations, will require more than a bibliometric approach.

Academies and Institutes↗
PubMed2004

Recalibration of the pediatric risk of admission score using a multi-institutional sample.

STUDY OBJECTIVE: Case-mix adjustment is a critical component of quality assessment and benchmarking. The Pediatric Risk of Admission (PRISA) score is composed of descriptive, physiologic, and diagnostic variables that provide a probability of hospital admission as an index of severity. The score was developed and validated in a single tertiary pediatric hospital emergency department (ED) after exclusion of children with minor injuries and illnesses. We provide a multi-institutional recalibration and validation of the PRISA score and test its performance in 4 additional EDs, including patients with minor injuries and illnesses. METHODS: Masked, photocopied, randomly selected medical records of ED patients from 2000 were abstracted and were used to test the performance (discrimination and calibration) of the original PRISA score. This sample differed from the original PRISA sample by including 5 hospitals and including patients with minor injuries and minor illnesses. Independent variables included components of acute and chronic history, physiologic variables, and 3 ED therapies. The dependent variable was hospital admission. PRISA was then recalibrated as needed by using an 80% development sample and a 20% validation sample. Area under the curve and the Hosmer-Lemeshow goodness-of-fit test were used to measure, respectively, discrimination and calibration of the PRISA score after recalibration. We then applied the recalibrated PRISA score to secondary outcomes to test construct validity. We reasoned that a valid measure of ED severity should also be associated with the secondary outcomes of mandatory admissions (admissions using > or =1 inpatient resources) and ICU admissions. RESULTS: The recalibrated PRISA score performed well in all deciles of predicted probability of admission. The area under the curve was 0.81 and the calibration was good (Hosmer-Lemeshow 10.658; df=8; P=.222) for the development sample, and the area under the curve was 0.785 with excellent calibration (Hosmer-Lemeshow 8.341; df=9; P=.500) for the validation sample. The overall development sample had 423.9 admissions predicted and 423 observed; the validation sample had 112.1 predicted and 110 observed. CONCLUSION: The PRISA score has been recalibrated and performs well in EDs of tertiary pediatric hospitals. Comparison with this benchmark may allow individual EDs to improve their performance and may provide insight into best practices.

Child↗
PubMedDate not supplied

Gene extraction for cancer diagnosis by support vector machines--an improvement.

OBJECTIVE: To improve the performance of gene extraction for cancer diagnosis by recursive feature elimination with support vector machines (RFE-SVMs): A cancer diagnosis by using the DNA microarray data faces many challenges the most serious one being the presence of thousands of genes and only several dozens (at the best) of patient's samples. Thus, making any kind of classification in high-dimensional spaces from a limited number of data is both an extremely difficult and a prone to an error procedure. The improved RFE-SVMs is introduced and used here for an elimination of less relevant genes and just for a reduction of the overall number of genes used in a medical diagnostic. METHODS: The paper shows why and how the, usually neglected, penalty parameter C and some standard data preprocessing techniques (normalizing and scaling) influence classification results and the gene selection of RFE-SVMs. The gene selected by RFE-SVMs is compared with eight other gene selection algorithms implemented in the Rankgene software to investigate whether there is any consensus among the algorithms, so the scope of finding the right set of genes can be reduced. RESULTS: The improved RFE-SVMs is applied on the two benchmarking colon and lymphoma cancer data sets with various C parameters and different standard preprocessing techniques. Here, decreasing C leads to the smaller diagnosis error in comparisons to other known methods applied to the benchmarking data sets. With an appropriate parameter C and with a proper preprocessing procedure, the reduction in a diagnosis error is as high as 36%. CONCLUSIONS: The results suggest that with a properly chosen parameter C, the extracted genes and the constructed classifier will ensure less overfitting of the training data leading to an increased accuracy in selecting relevant genes. Finally, comparison in gene ranking obtained by different algorithms shows that there is a significant consensus among the various algorithms as to which set of genes is relevant.

Algorithms↗
PubMed2004

A particle swarm optimizer with passive congregation.

This paper presents a particle swarm optimizer (PSO) with passive congregation to improve the performance of standard PSO (SPSO). Passive congregation is an important biological force preserving swarm integrity. By introducing passive congregation to PSO, information can be transferred among individuals of the swarm. A particle swarm optimizer with passive congregation (PSOPC) is tested with a set of 10 benchmark functions with 30 dimensions and compared to a global version of SPSO (GSPSO), a local version of SPSO (LSPSO), and PSO with a constriction factor (CPSO), respectively. Experimental results indicate that the PSO with passive congregation improves the search performance on the benchmark functions significantly.

Algorithms↗
PubMed2003

Analysis of quantization error in high-precision continuous-flow isotope ratio mass spectrometry.

High-precision isotope ratio mass spectrometry (IRMS) systems are equipped with digitizers that deliver effective maximum digitization depths of 16 to 24 bits; however, there are no analyses of the proper board depth required to retain high precision in continuous-flow techniques. We report an experimental and theoretical evaluation of quantization error in continuous-flow IRMS (CF-IRMS). CO2 samples (100 pmol-30 nmol) were injected into a gas chromatography combustion IRMS system (GC-CIRMS). The analog signal was digitized by high precision, 24-bit ADC boards at 10 Hz, and was post-processed to simulate 12, 14, and 16-bit data sets. Delta13Cpdh values were calculated for all data sets by the conventional "summation" method or by curve-fitting the chromatographic peaks to the exponentially modified Gaussian (EMG) function. Benchmarks of S.D.(delta13Cpdh) = 0.3, 0.6, and 1.0/1000 were considered to assess precision. In the presence of significant quantization noise, curve-fitting required several-fold less CO2 than the summation method to reach a given benchmark. We derived an equation to describe the theoretical limitations of precision for the summation method as a function of CO2 admitted to the source and the step size of the boards. Theory was in close agreement with the observed lower limit of precision for the simulated 16-bit data set. Curve-fitting achieved a precision of S.D. <0.3/1000 for injections 20-fold smaller than summation for CO2 samples collected on an IRMS with 16-bit resolution. By mitigating the impact of quantization noise, curve-fitting expands the dynamic range within a single run to include lower analyte levels, and effectively reduces the need for high pumping capacities and high precision ADC boards.

Isotopes↗
PubMed2004

Detecting and preventing the occurrence of errors in the practices of laboratory medicine and anatomic pathology: 15 years' experience with the College of American Pathologists' Q-PROBES and Q-TRACKS programs.

This review extracts those studies from the CAP Q-PROBES and Q-TRACKS programs that have benchmarked and monitored the occurrence of errors in the practices of laboratory medicine and anatomic pathology. The outcomes of these studies represent in aggregate the analysis of millions of data points collected in thousands of hospitals throughout the United States. Also presented in this review are hospital and laboratory practices associated with improved performance (ie, fewer errors). Only those associations that were shown to be statistically significant are presented. They represent only a small fraction of the practices examined in these studies. The reader is encouraged to peruse the Q-PROBES studies cited in the reference list to learn about the wide range of practices investigated. The institution of some of these practices for which the associated error reductions were not statistically significant might nonetheless improve performance in some environments. There is no way of knowing whether some better-performing institutions compensated for not employing presumably beneficial practices by applying other practices about which the studies' authors neglected to inquire. Nor is there any way of knowing whether institutions in which performance was poor employed presumably beneficial practices, but possessed operational flaws about which the studies' authors neglected to inquire. Certainly, hospitals operating in the bottom 10% of benchmarked performances would do well to investigate the possibility that some of these practices might reduce the incidence of errors in their institutions. From the results of these studies, there emerge two complementary strategies that appear to be associated with reduction of errors. Obviously, the first strategy involves doing what is necessary to prevent the occurrence of errors in the first place. Several tactics may accomplish this goal. Healthcare workers responsible for specific tasks must be properly educated and motivated to perform those tasks with as few errors as possible. There must be written policies and protocols detailing responsibilities and providing contingencies when those responsibilities are not met. The successful completion of required tasks must be documented, especially those tasks that are performed as requisite to others. In other words, it should be impossible to move on to subsequent operations in testing processes before documenting the successful completion of previous requisite operations. Finally, the opportunities for making errors must be reduced. Specifically, the number of steps in which specimens are delivered to laboratories, tests are performed, and results are disseminated to those who use them must be reduced as much as possible. The second strategy involves the assumption that despite our best efforts to prevent them, errors will occur. No matter how smart we are, no matter how careful we try to be, we will make mistakes. It is essential that systems designed to eliminate errors include elements of redundancy to catch those mistakes. Work must be checked and verified before therapeutic decisions are finalized. This is especially true when those decisions are irrevocable and the potential damage caused by errors cannot be undone. Ideally, systems that use redundancy should include provisions to shut down the testing process altogether when the successful execution of previous steps cannot be verified. Once error detection systems are established, service providers can gauge their performance by employing tools of continuous monitoring to assess the degree to which health care workers comply with required procedures, and with which services achieve their intended outcomes.

Diagnostic Errors↗
PubMed2026

Reinforcement learning-based dynamic ensemble for missense variant effect prediction and tiered prioritization of VUS.

BACKGROUND: Accurate classification of missense variants remains a challenging task despite major advances in genomics. Numerous computational models have been developed to assist in variant classification, but often require repeated integration and benchmarking efforts. Ensemble methods have been proposed to overcome the limitations of single predictors, but mostly rely on fixed, predefined weights that constrain their ability to capture interactions among predictive signals. METHODS: We present GenixRL, a dynamic ensemble framework that reformulates model fusion as a reinforcement learning optimization problem. GenixRL uses a Q-learning agent to learn a policy that dynamically weights the probabilistic outputs of complementary predictors, including BayesDel (addAF and noAF), ClinPred, and MetaRNN. Replacing static weighting with policy learning allows GenixRL to adaptively identify optimal weightings and substantially improve classification accuracy. RESULTS: In benchmark evaluation against 25 state-of-the-art predictors, GenixRL achieved an AUROC of 0.9644 on an independent ClinVar dataset. On saturation genome editing assays for BRCA1 and BRCA2, GenixRL achieved the best performance and ranked highest on 14 of 17 clinically significant genes in a zero-shot evaluation. Applied to uncertain and conflicting ClinVar variants, GenixRL enabled tiered, evidence-based prioritization of hundreds of thousands of variants as likely pathogenic or pathogenic with high confidence, supported by orthogonal population evidence from gnomAD. CONCLUSION: GenixRL advances pathogenicity prediction for missense variants and provides an adaptive ensemble that sorts variants of uncertain significance into tiered candidates for expert curation and functional validation.

Mutation, Missense↗
PubMed2026

Meta-PseU: A meta-classifier for robust prediction of RNA pseudouridine modification sites from long sequences.

BACKGROUND AND OBJECTIVES: Pseudouridine (&#x3a8;) represents one of the most abundant and conserved RNA modifications. &#x3a8; provides an additional hydrogen-bond donor that enhances RNA structural stability and modulates translation. It participates in diverse biological processes, including RNA-protein interactions, splicing, translational control, and stress responses. Aberrant pseudouridylation is implicated in cancer, neurodegenerative disorders, and autoimmune diseases. Despite its biological importance, experimental identification of &#x3a8; sites remains time-consuming and costly, limiting the feasibility of transcriptome-wide profiling. Computational approaches have therefore become essential complements to experimental techniques. However, state-of-the-art machine-learning and deep-learning predictors often suffer from limited generalizability due to small training datasets. To overcome these issues, we aim at constructing new long-sequence datasets and developing a novel &#x3a8; site predictor. METHODS: New long-sequence datasets were constructed as benchmarks for RNA &#x3a8;-site prediction. The &#x3a8; modification sites in RMBase 3.0 were mapped to the reference genomes across three species of human, mouse, and yeast, and the RNA sequences with a length of 201 were generated by extending the upstream and downstream from the mapped, central sites. To eliminate sequence redundancy, the sequences were clustered using CD-HIT with a 70% sequence identity threshold. We developed Meta-PseU, a logistic regression-based meta-classifier that considered 118 machine learning and deep learning classifiers. The datasets and programs are freely accessible at https://github.com/kuratahiroyuki/MetaPseU. RESULTS: By optimizing model configuration, we proposed the Meta-PseU model stacking 32 machine learning and deep learning classifiers out of 118 classifiers. Meta-PseU substantially improved model generalizability, overcoming a key limitation of existing approaches. It greatly outperformed state-of-the-art predictors and achieved increasing accuracy with increasing sequence length. CONCLUSIONS: Long-sequence datasets were newly constructed as benchmarks for RNA &#x3a8;-site prediction. Meta-PseU offers a new framework for robust &#x3a8;-site identification by using long sequences.

Pseudouridine↗
PubMed2004

Prediction of composite elastic modulus and polymerization shrinkage by computational micromechanics.

OBJECTIVES: The objective of this study was to simulate the elastic modulus and polymerization shrinkage of a light activated polymer matrix composite using a generalized method of cells (GMC) micromechanics model. Two hypotheses were tested: (1) the micromechanics model provides estimates of elastic modulus vs filler fraction with greater accuracy than the rule of mixtures, Hashin-Shtrikman and phenomenological models; (2) Micromechanics Analysis Code/Generalized Method of Cells accurately simulates experimental benchmarks of polymerization shrinkage strain. METHODS: The study applied mathematical algorithms to a representative volume element of a model polymer composite to yield value estimates of the elastic modulus and contraction strain. Mechanical properties of the composite constituents were derived from thermomechanical and dynamic mechanical analysis of BisGMA and TEGDMA filled and unfilled resins. Data from the micromechanics model were compared to results of other analytical methods as well as experimental benchmarks. RESULTS: Predictions of elastic modulus vs filler fraction from the micromechanics model provided greater accuracy than the rule of mixtures and the Hashin-Shtrikman models. Predictions of polymerization shrinkage strain were within 13% of experimental values. SIGNIFICANCE: The elastic micromechanics model presented accurately predicted elastic modulus and polymerization shrinkage strain as a function of filler fraction, superior to other analytical methods.

Bisphenol A-Glycidyl Methacrylate↗
PubMed2005

Chemical and ecotoxicological characterization of Columbia River sediments below the Hanford site (USA).

Columbia River sediments were characterized (metals, organics, porewater toxicity) with samples (n=12) from four dams below the Hanford site. Analyses were supplemented with colocated radionuclide data, along with comparable data from the Priest Rapids dam, immediately upriver from Hanford. Although not statistically significant (Bonferroni P>0.05), metals were generally highest at Priest Rapids, relative to downriver dams. Semivolatiles, Aroclors, and organochlorine pesticides were below method reporting limits. Radionuclide differences across locations were minor (Bonferroni P>0.05). Whereas Microtox showed little toxicity, Daphnia IQ tests exhibited measurable toxicity at all locations (EC50 = 22 - 78% porewater). Ecotoxicological benchmarks for metals were exceeded at several locations, most notably at Priest Rapids. Except for K-40, radionuclides were below benchmarks. Overall, chemistry and ecotoxicity results suggested that sediments may pose a risk to benthic biota, likely due to metals (derived largely from upriver mining) or factors associated with a reducing environment (e.g., low oxygen, high ammonia).

Animals↗
PubMed2004

Initial twelve months experience and analysis for 2001-2002 from the Australasian Society of Cardiac and Thoracic Surgeons--Victorian database project.

UNLABELLED: The Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) have established a database for the collection and analysis of the results of cardiac surgery in Australia and New Zealand. Initially data has been collected only in Victoria public hospitals. This report covers the first 12 months of data collection from 1st August 2001 to 1st July 2002. BACKGROUND: Whilst cardiac surgical performance in Australia is considered to be of a high standard equivalent to other developed countries, there is currently no systematic approach to data collection in order to provide performance indicators and benchmarks. The development of an Australasian cardiac surgical database and performance indicators will enable benchmarking and comparison with international standards which should lead to performance improvements. METHODS: A database definition set and standardised data collection form was developed by the ASCTS for all participating cardiac surgery units in public hospitals in Victoria. Opt-off consent for subject inclusion in the database was approved by each participating institutional ethics review committee. An electronic database and reporting application was developed. Data included in this analysis is from the initial 12 months collection from all hospitals participating in the project from 1st August 2001 to 31st July 2002. RESULTS: Overall, there were 2982 procedures performed in this period of which 2969 had sufficient data to be included in this analysis (99.5%). The majority of procedures 2017 (68%) being undertaken were isolated coronary artery bypass surgery (CABG). The mean age of all subjects undergoing procedures was 65 years (range: 18-91 years) and 70% were male. 64% of all procedures were elective and 6.1% emergency or salvage. Median post-procedure length of hospital stay for all procedures was 6.0 days and intensive care unit (ICU) stay was 23.0h. Re-operation for haemorrhage occurred in 2.1% of all cases and deep sternal infection in 0.4% of all cases. Crude 30-day operative mortality was 3.6% for all procedures; 2.1% for isolated CABG, 3.6% for valve procedures, 5.2% for valve and CABG and 11.4% for other cardiac surgical procedures. Mortality rates increased from 1.8% for elective procedures to 4.1% for urgent and 24.6% for emergency or salvage operations. In comparison to international figures from the USA and UK, mortality rates following isolated CABG were lower whilst average length of hospital stay post-procedure was higher. CONCLUSION: The ASCTS database project is now well established and the electronic database and reporting module is in operation in all participating sites. The risk-adjusted isolated operative mortality suggests cardiac surgical performance in Victoria compares well with international standards. As the database develops, local risk-adjustment models for mortality and morbidity for each procedure will be developed to enable appropriate between hospital comparisons.

Journal Article↗
PubMed2005

Hospitalized patients with atrial fibrillation and a high risk of stroke are not being provided with adequate anticoagulation.

OBJECTIVES: The purpose of this study was to determine both treatment gaps and predictors of warfarin use in atrial fibrillation (AF) patients enrolled in a national multicenter study. BACKGROUND: The National Anticoagulation Benchmark Outcomes Report (NABOR) is a performance improvement program designed to benchmark anticoagulation prophylaxis, treatment, and outcomes among participating hospitals. METHODS: A retrospective cohort study of inpatients was performed at 21 teaching, 13 community, and 4 Veterans Administration hospitals in the U.S. Patients with an ICD-9-CM code for AF (427.31) were randomly selected. RESULTS: Among the 945 patients studied, the mean age was 71.5 (+/- 13.5) years; 43% were >75 years of age, 54.5% were men, and 67% had a history of hypertension. Most (86%) had factors that stratified them as at high risk of stroke, and only 55% of those received warfarin. Neither warfarin nor aspirin were prescribed in 21% of high-risk patients, including 18% of those with a previous stroke, transient ischemic attack, or systemic embolic event. Age >80 years (p = 0.008) and perceived bleeding risk (p = 0.022) were negative predictors of warfarin use. Persistent/permanent AF (p < 0.001) and history of stroke, transient ischemic attack, or systemic embolus (p = 0.014) were positive predictors of warfarin use, whereas high-risk stratification was not. CONCLUSIONS: This study confirms the under-use of warfarin, but also adds to published reports in several regards. It showed that risk stratification, the guidepost for treatment in international guidelines, had little effect on warfarin use, and that age >80 years and AF classification (permanent/persistent) are factors that influence warfarin use.

Aged↗