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PubMed2006

Phased-ultrasonic receiving-planar array transducer for partial discharge location in transformer.

Partial discharge (PD) location in transformers is very important, and many methods that have been brought forward in past decades have a limitation theoretically, namely, they cannot locate multiple PDs in electrical equipment. In this paper, a new PD location method based on UHF and ultrasonic-phased arrays receiving theory has been presented, which has a possibility to locate multiple PDs. According to the method, a phased-ultrasonic receiving-planar array sensor that possesses 16 * 16 elements is designed; and, based on the phased-array theory, the characteristics of the plane sensor are studied. The laboratory experimental tests on the plane sensor element indicates that it has a good performance within the frequency band of the main ultrasonic energy produced by PD in transformer oil. Location tests are conducted on one or two piezoelectric ultrasonic sources in oil, which are both simulated as PD sources and triggered by an electrical pulse whose front is considered as a time benchmark in the locating algorithm. The test results show locations to one and two PDs can be realized in a single measurement, which lays a foundation for locating PDs in a power transformer in service.

Journal Article↗
PubMed2026

Library strategies differentially shape microbial, functional, and host signals in clinical metagenomic sequencing.

Metagenomic next-generation sequencing (mNGS) is increasingly used in infectious disease diagnostics, yet how library preparation shapes the microbial, functional, and host signals recovered from clinical samples remains poorly defined. Here, we performed a within-sample parallel comparison of three mNGS library preparation strategies-DNA-based libraries (DNAlib), RNA-based libraries (RNAlib), and total nucleic acid-based libraries (TNAlib)-across a diverse range of clinical specimens spanning five sample types. Using a curated clinical infectome as a benchmark, we show that library strategies are not interchangeable but capture distinct biological dimensions of the same specimen. RNAlib provided the most comprehensive standalone recovery of the clinical infectome, with improved detection of RNA viruses and cellular pathogens, enhanced resolution of resistance and virulence signals, and preservation of infection-associated host immune signatures. DNAlib showed stronger baseline recovery of DNA viruses and broader host genome coverage, whereas the TNAlib workflow evaluated here largely behaved as an intermediate strategy rather than a consistent improvement over dedicated DNA- or RNA-based workflows. Together, these results establish that the library preparation protocol is a major determinant of how clinical mNGS data should be interpreted and provide a framework for selecting sequencing strategies according to specific diagnostic and biological questions.IMPORTANCEMetagenomic sequencing is increasingly used in infectious disease research and clinical diagnostics, but different library preparation strategies may recover fundamentally different biological signals from the same sample. These signals include not only pathogens but also background microbes, microbial functional activity, and host immune-response patterns. Here, we systematically compared DNA-, RNA-, and total nucleic acid-based metagenomic sequencing libraries using the same clinical samples processed in parallel. We found that the three strategies did not provide equivalent information. RNA-based sequencing generated the most informative single-library view of infection, particularly for RNA viruses, cellular pathogens, functional microbial signals, and host immune-response patterns. DNA-based sequencing was more effective for DNA virus and host genome recovery, whereas the total nucleic acid sequencing workflow evaluated here generally behaved as an intermediate strategy. These findings show that library preparation can substantially influence the interpretation of metagenomic data.

functional characterization↗
PubMed2006

EQUAL-quant: an international external quality assessment scheme for real-time PCR.

BACKGROUND: Quantitative gene expression analysis by real-time PCR is important in several diagnostic areas, such as the detection of minimum residual disease in leukemia and the prognostic assessment of cancer patients. To address quality assurance in this technically challenging area, the European Union (EU) has funded the EQUAL project to develop methodologic external quality assessment (EQA) relevant to diagnostic and research laboratories among the EU member states. We report here the results of the EQUAL-quant program, which assesses standards in the use of TaqMan probes, one of the most widely used assays in the implementation of real-time PCR. METHODS: The EQUAL-quant reagent set was developed to assess the technical execution of a standard TaqMan assay, including RNA extraction, reverse transcription, and real-time PCR quantification of target DNA copy number. RESULTS: The multidisciplinary EQA scheme included 137 participating laboratories from 29 countries. We demonstrated significant differences in performance among laboratories, with 20% of laboratories reporting at least one result lacking in precision and/or accuracy according to the statistical procedures described. No differences in performance were observed for the >10 different testing platforms used by the study participants. CONCLUSIONS: This EQA scheme demonstrated both the requirement and demand for external assessment of technical standards in real-time PCR. The reagent design and the statistical tools developed within this project will provide a benchmark for defining acceptable working standards in this emerging technology.

European Union↗
PubMed2006

An eight-year analysis of surgical morbidity and mortality: data and solutions.

In this article, a reproducible process for presenting, analyzing, and reducing early and late surgical morbidity and mortality (M and M) is detailed. All M and M cases presented from 1998 through 2005 at Monmouth Medical Center were categorized. Residents and nurses were empowered to report the complications. The five major categories were overwhelming disease on admission, delays in treatment, diagnostic or judgment complications, treatment complications, and technical complications. From the 53,541 operations performed over 8 years, 714 patients were presented, which included 147 deaths and 1,132 category entries. The most common problems were technical complications in 474 (66.4%) patients. The data have generated actionable solutions, many with low barriers to adoption, resulting in safer, less expensive surgical management. Surgical outcome benchmarks have been established and are used for credentialing surgeons. The "Hostile Abdomen Index" has been developed to assess the safest choice for abdominal operative access, pre- and intraoperatively. We explained the real-time process that generated solutions for the entire department as well as changes relevant to residency training and individual operative techniques.

Follow-Up Studies↗
PubMed2001

An analysis of factors that influence the ASCUS/SIL ratio of pathologists.

In pursuit of physician-specific performance data in cytology, we have been calculating the ASCUS/SIL (atypical squamous cells of undetermined significance/squamous intraepithelial lesion) ratio of cytopathologists (CPs) and providing confidential feedback every 6 months. At the same time, thin-layer technology was introduced as an alternative to conventional smears. Thus we analyzed factors that may influence the ASCUS/SIL ratio, particularly the effect of periodic feedback on outliers (defined by a professional benchmark). For 3 years, the mean ASCUS/SIL ratio for all CPs decreased significantly from 2.92 to 1.87. There was great variability in the mean ASCUS/SIL ratio among 12 CPs (range, 1.11-5.89). Of the 6 CPs who worked continuously during this time, 2 showed a statistically significant decrease in their ASCUS/SIL ratio, including the CP with the highest ratio; 1 showed a significant increase. The mean ASCUS/SIL ratio did not correlate well with years of CP experience or with individual annual case volume. The ASCUS/SIL ratio of some CPs can decrease significantly over time. Whether it was due to feedback or the introduction of thin-layer preparations could not be determined.

Feedback↗
PubMed2004

World health system performance revisited: the impact of varying the relative importance of health system goals.

BACKGROUND: In 2002, the World Health Organization published a health system performance ranking for 191 member countries. The ranking was based on five indicators, with fixed weights common to all countries. METHODS: We investigate the feasibility and desirability of using mathematical programming techniques that allow weights to vary across countries to reflect their varying circumstances and objectives. RESULTS: By global distributional measures, scores and ranks are found to be not very sensitive to changes in weights, although differences can be large for individual countries. CONCLUSIONS: Building the flexibility of variable weights into calculation of the performance index is a useful way to respond to the debates and criticisms appearing since publication of the ranking.

Benchmarking↗
PubMed2005

Impact of a common CV evaluation scheme on overall laboratory performance: 8-year experience of a large national proficiency testing program in Japan.

In proficiency testing (PT), it is difficult to set rational criteria for determining target values and allowable limits. In Japan, the largest national PT program has for the past 8 years used an evaluation scheme based on a "common coefficient of variation" (cCV) to overcome this difficulty. The cCV, the average within-method variation, is derived by one-way analysis of variance from data of peer groups after excluding those with large variations. A unit interval used for grading participants is obtained by multiplying the cCV by the peer-group mean which is computed using an iterative method featuring repeated removal of a large portion of the tails of the distribution and reinflation of the standard deviation (SD) to compensate for the trimming. The evaluation scheme gives a relatively better grade to those participants in peer groups with small CVs, compared to use of individual peer-group CVs. The scheme has expedited the transition to more reproducible methods, resulting in a notable overall improvement in laboratory performance. The cCV evaluation scheme is uniformly applicable to any analyte measured quantitatively. The iterative method, an integral part of the scheme, effectively precludes bias in the evaluation.

Amylases↗
PubMed2002

Performance measurement now.

We are at the beginning of a significant increase in the use of performance measurement in hospice. Our resources for measuring performance are improving, while our environment is increasingly challenging. It is worth revisiting the goal of performance measurement in order to know your organization so well that you can continuously identify and act on the specific improvement opportunities that will have the greatest impact on overall results.

Benchmarking↗
PubMed2002

Sizing up HEDIS: experts take system's measure.

NCQA's performance measurement system is well established in the industry. But is it really addressing the questions that matter? In this article, industry experts discuss how HEDIS has made its mark.

Accreditation↗
PubMed2006

Pancreaticoduodenectomy in a community general surgery residency program.

The morbidity and mortality of pancreaticoduodenectomy (PD) has been well documented. A retrospective review was performed to determine the morbidity and mortality of PD performed within the general surgery residency program of a tertiary community hospital. Patients undergoing PD for benign or malignant disease over a 6-year period were analyzed to determine overall mortality, major complication rate, and length of stay (LOS). Of 50 consecutive patients undergoing PD, overall mortality was 6 per cent, with a major complication rate of 52 per cent. Mean operative time was 333 +/- 68 minutes with an estimated blood loss of 459 +/- 301 mL. Mean hospital LOS was 21 +/- 13 days. Eighty-four per cent of patients with malignant disease had negative margins of resection. General surgery residents within a community residency program, with attending faculty supervision, can perform PD with mortality, morbidity, and LOS comparable with that reported in the university setting.

Adolescent↗
PubMedDate not supplied

A new scale for assessing perceptions of chance: a validation study.

BACKGROUND: Clinicians and researchers often wish to know how patients perceive the likelihoods of health risks. Little work has been done to develop and validate scales and formats to measure perceptions of event probabilities, particularly low probabilities (i.e., <1%). OBJECTIVE: To compare a new visual analog scale with three benchmarks in terms of validity and reliability. DESIGN: Survey with retest after approximately two weeks. Respondents estimated the probabilities of six events with the new scale, which featured a "magnifying glass" to represent probabilities between 0 and 1% on a logarithmic scale. Participants estimated the same probabilities on three benchmarks: two linear visual analog scales (one labeled with words, one with numbers) and a "1 in x" scale. SUBJECTS: 100 veterans and family members and 107 university faculty and students. MEASURES: For each scale, the authors assessed: 1) validity-the correlation between participants' direct rankings (i.e., numbering them from 1 to 6) and scale-derived rankings of the relative probabilities of six events; 2) test-retest reliability-the correlation of responses from test to retest two weeks later; 3) usability (missing/ incorrect responses, participant evaluation). RESULTS: Both the magnifier and the two linear scales outperformed the "1 in x" scale on all criteria. The magnifier scale performed about as well as the two linear visual analog scales for validity (correlation between direct and scale-derived rankings = 0.72), reliability (test-retest correlation = 0.55), and usability (2% missing or incorrect responses, 65% rated it easy to use). 62% felt the magnifier scale was a "very good or good" indicator of their feelings about chance. The magnifier scale facilitated expression of low-probability judgments. For example, the estimated chance of parenting sextuplets was orders of magnitude lower on the magnifier scale (median perceived chance 10(-5)) than on its linear counterpart (10(-2)). Participants' assessments of high-probability events (e.g., chance of catching a cold in the next year) were not affected by the presence of the magnifier. CONCLUSIONS: The "1 in x" scale performs poorly and is very difficult for people to use. The magnifier scale and the linear number scale are similar in validity, reliability, and usability. However, only the magnifier scale makes it possible to elicit perceptions in the low-probability range (<1%).

Adult↗
PubMed2005

A statistical analysis of random mutagenesis methods used for directed protein evolution.

We have developed a statistical method named MAP (mutagenesis assistant program) to equip protein engineers with a tool to develop promising directed evolution strategies by comparing 19 mutagenesis methods. Instead of conventional transition/transversion bias indicators as benchmarks for comparison, we propose to use three indicators based on the subset of amino acid substitutions generated on the protein level: (1) protein structure indicator; (2) amino acid diversity indicator with a codon diversity coefficient; and (3) chemical diversity indicator. A MAP analysis for a single nucleotide substitution was performed for four genes: (1) heme domain of cytochrome P450 BM-3 from Bacillus megaterium (EC 1.14.14.1); (2) glucose oxidase from Aspergillus niger (EC 1.1.3.4); (3) arylesterase from Pseudomonas fluorescens (EC 3.1.1.2); and (4) alcohol dehydrogenase from Saccharomyces cerevisiae (EC 1.1.1.1). Based on the MAP analysis of these four genes, 19 mutagenesis methods have been evaluated and criteria for an ideal mutagenesis method have been proposed. The statistical analysis showed that existing gene mutagenesis methods are limited and highly biased. An average amino acid substitution per residue of only 3.15-7.4 can be achieved with current random mutagenesis methods. For the four investigated gene sequences, an average fraction of amino acid substitutions of 0.5-7% results in stop codons and 4.5-23.9% in glycine or proline residues. An average fraction of 16.2-44.2% of the amino acid substitutions are preserved, and 45.6% (epPCR method) are chemically different. The diversity remains low even when applying a non-biased method: an average of seven amino acid substitutions per residue, 2.9-4.7% stop codons, 11.1-16% glycine/proline residues, 21-25.8% preserved amino acids, and 55.5% are amino acids with chemically different side-chains. Statistical information for each mutagenesis method can further be used to investigate the mutational spectra in protein regions regarded as important for the property of interest.

Amino Acid Substitution↗
PubMed2005

On the choice of expansion functions in the Helmholtz equation least-squares method.

This paper examines the performance of Helmholtz equation least-squares (HELS) method in reconstructing acoustic radiation from an arbitrary source by using three different expansions, namely, localized spherical waves (LSW), distributed spherical waves (DSW), and distributed point sources (DPS), under the same set of measurements. The reconstructed acoustic pressures are validated against the benchmark data measured at the same locations as reconstruction points for frequencies up to 3275 Hz. Reconstruction is obtained by using Tikhonov regularization or its modification with the regularization parameter selected by error-free parameter-choice methods. The impact of the number of measurement points on the resultant reconstruction accuracy under different expansion functions is investigated. Results demonstrate that DSW leads to a better-conditioned transfer matrix, yields more accurate reconstruction than both LSW and DPS, and is not affected as much by the change in measurement points. Also, it is possible to obtain optimal locations of the auxiliary sources for DSW, LSW, and DPS by taking an independent layer of measurements. Use of these auxiliary sources and an optimal combination of regularization and error-free parameter choice methods can yield a satisfactory reconstruction of acoustic quantities on the source surfaces as well as in the field in the most cost-effective manner.

Journal Article↗
PubMed2001

The missions of medical schools: the pursuit of health in the service of society.

Mission statements and role documents of medical schools in the United Kingdom, United States, Canada and Australia have been examined on their Internet Web sites and categorised in purpose, content and presentation. The format and content are highly variable, but there is a common vision of three integral roles, namely, education, advancement of knowledge and service to society. Other frequent themes include tradition and historical perspective, service for designated communities, and benchmarking to accreditation standards. Differences in content reflect variable interpretation of the notion of "mission", and local or national characteristics such as institutional affiliations, the types, levels and organisation of medical education, relationships with health systems, and extent of multi-professional education. Outcomes data and measures of medical school performance referenced to the institution's stated missions are rarely encountered. Mission documents placed on the Internet are in the public domain. These Web sites and documents and linked information constitute a valuable new resource for international exchange of approaches and ideas in medical education and generally in academic medicine. Routine inclusion of outcome or performance data could help to demonstrate the community roles and social accountability of medical schools This paper proposes that partial standardisation of these Web documents could enhance their value both internally and for external readers. A generic descriptive statement template is offered.

Australia↗
PubMed2002

Diagnosis and subclassification of breast carcinoma by fine-needle aspiration biopsy: results of the interlaboratory comparison program in non-gynecologic cytopathology.

CONTEXT: The College of American Pathologists Interlaboratory Comparison Program in Non-Gynecologic Cytopathology is a popular educational program for nongynecologic cytology that had 1018 participating laboratories by the end of 2000. Data generated from this program allow for tracking performance on slides in a diverse group of laboratories. OBJECTIVE: We reviewed the performance of participating laboratories on fine-needle aspiration biopsies of the breast with particular interest in the ability of participants to accurately subclassify breast carcinoma. DESIGN: We reviewed the responses of participating laboratories for glass slides of breast fine-needle aspiration biopsies for the year 2000. We analyzed benchmarking data provided for each specific diagnosis. RESULTS: The overall false-negative rate for laboratories was 6.2%, and the overall false-positive rate was 1.1%. Most of the breast carcinomas were correctly identified as malignant on the general diagnosis, but participants had more difficulty subclassifying types of breast carcinoma. The rate of correct exact diagnosis was 65% for ductal adenocarcinoma, 20% for lobular adenocarcinoma, 12% for medullary carcinoma, and 27% for mucinous carcinoma. CONCLUSIONS: This study shows that fine-needle aspiration biopsy of the breast is a reliable method for the diagnosis of breast carcinoma, but difficulties still exist in our ability to determine tumor subtype.

Biopsy, Needle↗
PubMed2002

Cluster analysis of Wisconsin Breast Cancer dataset using self-organizing maps.

This work deals with multidimensional data analysis, precisely cluster analysis applied to a very well known dataset, the Wisconsin Breast Cancer dataset. After the introduction of the topics of the paper the cluster analysis concept is shortly explained and different methods of cluster analysis are compared. Further, the Kohonen model of self-organizing maps is briefly described together with an example and with explanations of how the cluster analysis can be performed using the maps. After describing the data set and the methodology used for the analysis we present the findings using textual as well as visual descriptions and conclude that the approach is a useful complement for assessing multidimensional data and that this dataset has been overused for automated decision benchmarking purposes, without a thorough analysis of the data it contains.

Breast Neoplasms↗