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At least 1,423 records · Page 79Linked to original sources
PubMed2006

The accuracy of WinSmash delta-V estimates: the influence of vehicle type, stiffness, and impact mode.

The objective of this paper is to investigate the accuracy of WinSmash delta-V estimates as a function of crash mode, vehicle body type, and vehicle stiffness. The accuracy of WinSmash delta-V estimates was evaluated for 121 NASS/CDS 2000-2003 cases for which direct measurements of delta-V had been retrieved from an Event Data Recorder on the case vehicle. WinSmash was found to underestimate delta-V by 23% on average. WinSmash was found to be most accurate in crashes involving full frontal engagement of the vehicle structure. When using categorical stiffness coefficients, the accuracy of delta-V estimates was found to be a strong function of vehicle type. WinSmash underestimated delta-V for pickup trucks by only 3%, but underestimated delta-V for front-wheel drive cars by 31%. The use of vehicle-specific stiffness coefficients improved the accuracy of the longitudinal delta-V estimate. The single most important factor in improving WinSmash accuracy was the inclusion of restitution. After adjusting for restitution, WinSmash underestimated delta-V in frontal crashes by only 1% on average.

Acceleration↗
PubMed1992

Indirect intracranial volume measurements using CT scans: clinical applications for craniosynostosis.

This paper describes a method for obtaining indirect intracranial volume measurements using CT scans with CTpak, a software package for quantitative analysis of CT scan data. The validity of this technique was confirmed by comparing direct measurement of the intracranial volume of five dry skulls with axial scans at 1.5- and 4-mm slice intervals to determine indirect volume. The indirect intracranial volume measurement technique was then used to compare preoperative and postoperative intracranial volume in 30 patients with craniosynostosis who underwent cranial vault and orbital osteotomies with reshaping and advancement. Our findings show that the suture release and simultaneous reshaping procedures usually carried out are, in fact, associated with increased intracranial volume. The observed intracranial volume gain is attributable to a combination of factors, including the surgical procedure carried out and ongoing growth. These factors are further modified by the diagnosis, age of the patient, and time interval between CT scans.

Age Factors↗
PubMed1997

[Healing modalities in unstable tibial fractures treated by locked flexible intramedullary fixation].

PURPOSE OF THE STUDY: This clinical study aimed specifically to evaluate the role of flexibility in aseptic consolidation of unstable tibial fractures on compact bones. The device employed was made of intramedular nails placed separately and locked together using an original proximal system. MATERIAL: 125 unstable compact bone fractures of the tibial shaft were treated by this method for almost 6 years. 110 cases were included in this study. 30 per cent of the fractures were open. The topographical breakdown of fracture sites on the diaphysis was 6 times, in the upper third (Sector I), 23 times in Sector II and 66 times in the lower third (Sector III). In 13 cases, there were sequential fractures of which the upper site was in Sector I. 57 cases were simple sites (A), 27 were sites with edges greater than 50 per 100 of the diaphyseal circumference (B), and 26 per 100 of comminuted sites (C). The distance measured in the fracture sites after osteosynthesis were 66 times within 3 mm, 24 cases from 4 to 10 mm, 12 cases from 11 to 15 mm, and 8 cases over 16 mm. METHODS: 110 cases were followed for more than 6 months. Consolidation was established on standard clinical and radiological criteria. The value of parameters affecting consolidation and the time period recorded were validated by a precise statistical evaluation using Stat. View II software, and Fisher and Yates tables. RESULTS: Complications due to implants were rare and minor. There were only 4 cases of nonunion resulting from secondary desaxation of two pins apparatus. 16 cases of nonunion (14.5 per 100) were recorded but 3 were forseeable nonunions, because of a traumatic bone loss. 8 cases were Sector I fractures of which 7 were Sector I unsequental fractures. 7 cases had a gap of 10 to 15 mm, and 5 of 16 to 20 mm. Thus 42.1 per 100 of cases in Sector I were not consolidated compared to only 6.1 per 100 of cases in Sector III. Primary consolidation of the 94 cases was achieved in an average of 11.08 +/- 3.19 weeks (minimum 6 weeks, maximum 20 weeks). Time for consolidation did not appear to be affected by anatomical type, opened fracture (degree 1 or 2) nor number of nails used. But, there were significant differences according to topography and postoperative gap at the fracture site. Sector II fractures took 15 days less than Sector I fracture: average 10.5 as compared to 12.6 weeks. The cases with a gap of 0 to 3 mm consolidated at an average of 10.6 weeks, those with 4 to 10 mm: 11.39 weeks, with a gap of 11 to 15 mm: 14.4 weeks, and the cases superior to 16 mm: 14.8 weeks. DISCUSSION: Compared to the interlocking nail, this procedure gave an average shortening of consolidation delay of 1 month for closed and degree 1 and 2 open fractures. This rapidity of consolidation can only be explained by the flexibility parameter. Thus it is only the flexibility of the device which can explain that even with a gap of 11 to 15 mm left within the fracture site, consolidation occurred 1 time out of 2 and 9 times out of 10 when the gap was 4 to 10 mm. Finally, this mechanical parameter can explain that consolidation is by far the shortest for low fractures although these are reputed to be the least osteogenic.

Adult↗
PubMed2004

Isotopica: a tool for the calculation and viewing of complex isotopic envelopes.

The web application Isotopica has been developed as an aid to the interpretation of ions that contain naturally occurring isotopes in a mass spectrum. It allows the calculation of mass values and isotopic distributions based on molecular formulas, peptides/proteins, DNA/RNA, carbohydrate sequences or combinations thereof. In addition, Isotopica takes modifications of the input molecule into consideration using a simple and flexible language as a straightforward extension of the molecular formula syntax. This function is especially useful for biomolecules, which are often subjected to additional modifications other than normal constituents, such as the frequently occurring post-translational modification in proteins. The isotopic distribution of any molecule thus defined can be calculated by considering full widths at half maximum or mass resolution. The combined envelope of several overlapping isotopic distributions of a mixture of molecules can be determined after specifying each molecule's relative abundance. The results can be displayed graphically on a local PC using the Isotopica viewer, a standalone application that is downloadable from the sites below, as a complement to the client browser. The m/z and intensity values can also be obtained in the form of a plain ASCII text file. The software has proved to be useful for peptide mass fingerprinting and validating an observed isotopic ion distribution with reference to the theoretical one, even from a multi-component sample. The web server can be accessed at http://bioinformatica.cigb.edu.cu/isotopica and http://coco.protein.osaka-u.ac.jp/isotopica [correction].

Amino Acid Sequence↗
PubMed2006

Validity and reliability of active shape models for the estimation of Cobb angles in adolescent idiopathic scoliosis.

Choosing the most suitable treatment for scoliosis relies heavily on accurate and reproducible Cobb angle measurement from successive radiographs. The objective is to reduce variability of Cobb angle measurement by reducing user intervention and bias. Custom software to automate Cobb angle measurement from posteroanterior radiographs was developed using active shape models. Validity and reliability of the automated system against a manual and semi-automated measurement method was conducted by two examiners each performing measurements on 3 occasions from a test set (N=22). A training set (N=47) of radiographs representative of curves seen in a scoliosis clinic was used to train the software to recognize vertebrae from T4 to L4. Images with a maximum Cobb angle between 20 degrees and 50 degrees, excluding surgical cases, were selected for training and test sets. Automated Cobb angles were calculated using best-fit slopes of the detected vertebrae endplates. Intra-class correlation coefficient (ICC) and standard error of measurement (SEM) showed high intra-examiner (ICC > 0.90, SEM 2-3 degrees) and inter-examiner (ICC > 0.82, SEM 2-4 degrees), but poor inter-method reliability (ICC=0.30, SEM 8-9 degrees). The automated method underestimated large curves. The reliability improved (ICC = 0.70, SEM 4-5 degrees) with exclusion of the 4 largest curves (>40 degrees) in the test set. The automated method was reliable for moderate sized curves, but did not properly detect vertebrae in larger curves. Optimization of constraints on scaling, rotation, translation, and iteration may improve reliability with larger curves.

Adolescent↗
PubMedDate not supplied

[Numerical simulation (FEM) of the human mandible: validation of the function of the masticatory muscles].

The article describes part of a research project aiming to develop a new modular software tool for the individual dynamic numerical simulation of the human mandible using the finite element method (FEM). Its planned use in the clinical setting makes it very important to validate the results of the simulations. Here, the function of the masticatory muscles is to be tested. On the basis of biomechanical data from the literature, standard movements, such as closing the mouth, forward movement, lateral movement or backward movement, were dynamically simulated. Apart from muscle activity, the movements of the mandible are defined by the temporomandibular joint. At present, translating the condylar dynamics to the simulation still poses problems. For this reason, therefore, simulations of the two extreme cases "fixed" and "force-free" condyles are compared. While in the case of fixed condyles, some of the movements could be reproduced either not at all or only weakly, in the case of force-free condyles, all standard movements were reproduced qualitatively, albeit without the guiding effect of the joint capsule or the articular disc.

Biomechanical Phenomena↗
PubMed2004

Transforming clinical dictation into structured notes in an ambulatory care practice.

Structured clinical encounter notes offer many advantages compared to free text notes. However, cost and other issues limit their widespread use. At our institution, the electronic medical record (EMR) used by an Internal Medicine practice was designed years ago to utilize structured data. This paper describes a technique to improve the process by which structured notes are dictated and transcribed. We outsourced transcription services and then passed the files through parsing software to structure the data to the granularity required for our database. Software was built to handle all aspects of the process including file validation, parsing, and review. During our pilot project, more than 10,000 notes were parsed, reviewed and uploaded into the EMR.

Ambulatory Care↗
PubMed2006

Megakaryocytic features useful for the diagnosis of myeloproliferative disorders can be obtained by a novel unsupervised software analysis.

An unsupervised method for megakaryocyte detection and analysis is proposed, in order to validate supplementary tools which can be of help in supporting the pathologist in the classification of Philadelphia negative chronic myeloproliferative disorders with thrombocytosis. The experiment was conducted on high power magnification photomicrographs taken from hematoxylin-and-eosin 3 micrometer thick sections of formalin fixed, paraffin embedded bone marrow biopsies from patients with reactive thrombocytosis or chronic myeloproliferative disorders. Each megakaryocyte has been isolated in the photos through an image segmentation process, mainly based on mathematical morphology and wavelet analysis. A set of features (e.g. area, perimeter and fractal dimension of the cell and its nucleus, shape complexity via elliptic Fourier transform, and so on) is used to characterize the disorders and discriminate between essential thrombocythemia and idiopathic myelofibrosis. Features related to the general contour of the cell like cytoplasmic area and perimeter are good markers in distinguishing between normal or reactive and pathologic megakaryocytes while nuclear features and global circularity are helpful in the differential diagnosis between ET and prefibrotic IMF. The method proposed should be considered as a fast preprocessing tool for the diagnostic phase and its use can be extended to solve different object recognition problems.

Bone Marrow Cells↗
PubMed2006

A local influence sensitivity analysis for incomplete longitudinal depression data.

In the analyses of incomplete longitudinal clinical trial data, there has been a shift, away from simple ad hoc methods that are valid only if the data are missing completely at random (MCAR), to more principled (likelihood-based or Bayesian) ignorable analyses, which are valid under the less restrictive missing at random (MAR) assumption. The availability of the necessary standard statistical software allows for such analyses in practice. Although the possibility of data missing not at random (MNAR) cannot be ruled out, it is argued that analyses valid under MNAR are not well suited for the primary analysis in clinical trials. Therefore, rather than either forgetting about or blindly shifting to an MNAR framework, the optimal place for MNAR analyses is within a sensitivity analysis context. Such analyses can be used, for example, to assess how sensitive results from an ignorable analysis are to possible departures from MAR and how much results are affected by influential observations. In this article, we apply the local influence sensitivity tool (Verbeke et al., 2001) to a longitudinal depression trial, thereby applying it to continuous outcomes from clinical trials.

Antidepressive Agents↗
PubMed2002

New generation pharmacogenomic tools: a SNP linkage disequilibrium Map, validated SNP assay resource, and high-throughput instrumentation system for large-scale genetic studies.

Since public and private efforts announced the first draft of the human genome last year, researchers have reported great numbers of single nucleotide polymorphisms (SNPs). We believe that the availability of well-mapped, quality SNP markers constitutes the gateway to a revolution in genetics and personalized medicine that will lead to better diagnosis and treatment of common complex disorders. A new generation of tools and public SNP resources for pharmacogenomic and genetic studies--specifically for candidate-gene, candidate-region, and whole-genome association studies--will form part of the new scientific landscape. This will only be possible through the greater accessibility of SNP resources and superior high-throughput instrumentation-assay systems that enable affordable, highly productive large-scale genetic studies. We are contributing to this effort by developing a high-quality linkage disequilibrium SNP marker map and an accompanying set of ready-to-use, validated SNP assays across every gene in the human genome. This effort incorporates both the public sequence and SNP data sources, and Celera Genomics' human genome assembly and enormous resource ofphysically mapped SNPs (approximately 4,000,000 unique records). This article discusses our approach and methodology for designing the map, choosing quality SNPs, designing and validating these assays, and obtaining population frequency ofthe polymorphisms. We also discuss an advanced, high-performance SNP assay chemisty--a new generation of the TaqMan probe-based, 5' nuclease assay-and high-throughput instrumentation-software system for large-scale genotyping. We provide the new SNP map and validation information, validated SNP assays and reagents, and instrumentation systems as a novel resource for genetic discoveries.

Alleles↗
PubMed2006

SPINS: a laboratory information management system for organizing and archiving intermediate and final results from NMR protein structure determinations.

Recent technological advances and experimental techniques have contributed to an increasing number and size of NMR datasets. In order to scale up productivity, laboratory information management systems for handling these extensive data need to be designed and implemented. The SPINS (Standardized ProteIn Nmr Storage) Laboratory Information Management System (LIMS) addresses these needs by providing an interface for archival of complete protein NMR structure determinations, together with functionality for depositing these data to the public BioMagResBank (BMRB). The software tracks intermediate files during each step of an NMR structure-determination process, including: data collection, data processing, resonance assignments, resonance assignment validation, structure calculation, and structure validation. The underlying SPINS data dictionary allows for the integration of various third party NMR data processing and analysis software, enabling users to launch programs they are accustomed to using for each step of the structure determination process directly out of the SPINS user interface.

Computer Graphics↗
PubMed2004

Prednisolone: limited sampling strategies for estimating pharmacokinetic parameters.

To develop limited-sampling strategy (LSS) models for estimating prednisolone's area under plasma concentration versus time curve (AUC(0-infinity)), its maximum concentration in plasma (C(max)), and total clearance (CL/F). Healthy subjects (n = 24), enrolled in a bioequivalence study, received 20 mg PO of the prodrug prednisone as reference and test tablets, and plasma prednisolone concentrations (n = 576) were measured by a validated HPLC assay. A linear regression analysis of AUC(0-infinity), C(max), CL/F, and log(CL/F) against the plasma prednisolone concentrations for the reference formulation was carried out to develop LSS models to estimate these parameters. The LSS models were validated on the test formulation data sets and on simulated sets generated by the software ADAPT II. LSS models based on a single [1.5 hours for C(max) and 7 hours for AUC(0-infinity), CL/F, and log(CL/F)] plasma sample, accurately estimated (R2 = 0.84-0.97, mean bias < 1%; mean precision < 10%) these pharmacokinetic parameters. Validation tests indicated that the most informative single-point LSS models developed for the reference formulation provide precise estimates (R(2) > 0.83; mean bias < 3%; mean precision < 10%) of the corresponding pharmacokinetic parameters for the test formulation. LSS models based on the two most informative sampling points (1.5 and 7 hours) were required for accurate estimates (R(2) > 0.87; mean bias < 6%; mean precision < 8%) of prednisolone's C(max), AUC(0-infinity), CL/F, and log(CL/F) for the simulated data sets. Finally, bioequivalence assessment of the prednisone formulations, based on LSS-derived AUC(0-infinity) and C(max) values provided results identical to those obtained using the original values for these parameters. One- and 2-point LSS models provided accurate estimates of prednisolone's C(max), AUC(0-infinity), and CL/F, following single oral doses of prednisone, and allowed correct assessment of bioequivalence between two prednisone formulations.

Adolescent↗
PubMed2006

ASM1 dynamic calibration and long-term validation for an intermittently aerated WWTP.

Activated sludge models, and ASM1 in particular, are well recognised and useful mathematical representations of the macroscopic processes involved in the biological degradation of the pollution carried by wastewater. Nevertheless, the use of these models through simulation software requires a careful methodology for their calibration (determination of the model parameters' values) and the validation step (verification with an independent data set). This paper presents the methodology and the results of dynamic calibration and validation tasks as a prior work to a modelling project for defining a reference guideline destined to French designers and operators. To reach these goals, a biological nutrient removal (BNR) wastewater treatment plant (WWTP) with intermittent aeration was selected and monitored for 2 years. Two sets of calibrated parameters are given and discussed. The results of the long-term validation task are presented through a 2-month simulation with lots of operation changes. Finally, it is concluded that, even if calibrating ASM1 with a high degree of confidence with a single set of parameters was not possible, the results of the calibration are sufficient to obtain satisfactory results over long-term dynamic simulation. However, simulating long periods reveals specific calibration issues such as the variation of the nitrification capacity due to external events.

Aerobiosis↗
PubMed2000

Use of optimization software to determine rugged analysis conditions in high-performance liquid chromatography.

The ruggedness evaluation of an analytical method is now generally required for further validation. By considering ruggedness at an early stage of method development, major disappointments and amount of work could be avoided. This work shows that the optimization software OSIRIS can be helpful for the chromatographer during a method development, as it takes into account the method ruggedness. The ruggedness of the analysis conditions is then evaluated all along the selectivity optimization procedure. This optimization software belongs to the interpretive methods that consist of predicting the optimum conditions by modeling first the solute retention over the parameter space using a minimum number of preliminary runs. The choice of a response function is studied. This response function must be able to take into account several individual criteria: analysis time, minimal resolution and ruggedness of each parameter. Some optimum separations, determined using a ruggedness criteria or not, are given and compared in terms of long term repeatability.

Chromatography, High Pressure Liquid↗
PubMed2006

A web-based system for tissue microarray data management.

BACKGROUND: Tissue Microarray is a novel technique for analysing large amounts of immunohistochemically stained specimens. However, those large amounts make it difficult to design, prepare and analyze a tissue microarray, so that software support is almost inevitable. METHODS: We designed a tissue microarray data management system starting from specifications obtained by pathologists, and arranged for a preliminary validation in thyroid pathology. RESULTS: A web-based system has been developed, basing on open-source software and principles, that was well accepted by pathologists and allowed to carry out a study on 52 thyroid pathology cases. CONCLUSION: Though limited in functionalities, the developed system is effective and can be downloaded at the address http://mitel.dimi.uniud.it/timan/.

Journal Article↗
PubMed1995

Quantitative analysis of computed tomography scans of the lungs for the diagnosis of pulmonary emphysema. A validation study of a semiautomated contour detection technique.

RATIONALE AND OBJECTIVES: To develop an analytic software package based on automated contour detection for the objective and reproducible assessment of emphysema from computed tomography (CT) scans. METHODS: A semiautomated technique was developed for the definition of lung contours in CT cross-sections followed by the assessment of pulmonary CT parameters describing the disease state. For 78 images, the semiautomated contour detection was performed and compared with contours drawn by an experienced radiologist by calculating the systematic area difference (bias) and differences in pulmonary CT parameters such as the mean lung density (MLD). In addition, intraobserver and interobserver variabilities were determined in a subset of 15 images. RESULTS: The areas enclosed by the semiautomatically detected contours were slightly larger than the manual ones (bias < 2.1%). The biases in the observer studies were smaller in the semiautomated versus the manual case (0.3% vs. 1.3%). The standard deviation of the MLD differences with a manual analysis was larger by a factor of five than in the semiautomated case. On average, manual analysis required 2 minutes, 18 seconds per lung; this time was reduced to 11.5 to 29 seconds with the semiautomated approach, depending on the respiration state. CONCLUSIONS: The semiautomated approach is preferred over the manual approach because of its higher consistency and its shorter analysis time.

Adult↗
PubMed1990

Using a computerized method to measure 99mTc pertechnetate uptake for the assessment of thyroid function: a clinical validation.

This retrospective study evaluated thyroid function by the 99mTc pertechnetate uptake ratio, using computer software designed in our laboratory. We expected that this measurement could be a precise and accurate index. The following studies were performed on 187 patients: (1) 24-hour radioimmunoassay of serum thyroid hormones, including serum thyroxine, free T4, triiodothyronine, thyrotropin concentrations, and T3 resin uptake; (2) 99mTc pertechnetate thyroid imaging and uptake measurement; and (3) 24-hour 131I thyroid uptake. Based on the clinical findings and the results from the predescribed laboratory tests, we found that: (1) the mean value of the 99mTc pertechnetate thyroid uptake ratio in the euthyroid groups was 2.77 +/- 1.77% (mean +/- SD); (2) the correlation coefficient between the 99mTc pertechnetate thyroid uptakes and the 24-hour 131I uptakes of the euthyroid patients was 0.71; and (3) hyperthyroidism could be distinguished from euthyroid condition easily. By setting the upper limit of euthyroid 99mTc pertechnetate thyroid uptake at 6.31%, the diagnostic sensitivity was 92.9%, specificity 96.1%, and accuracy 95.6% in separating hyperthyroid from euthyroid patients. These values were similar to those determined by the 24-hour 131I uptake measurements. Thus, thyroid function can be evaluated simultaneously with a routine 99mTc pertechnetate thyroid scan. Both the patient time and cost can be saved with this method, since the measurement takes only 25 minutes. Decreased radiation exposure is another advantage of this method over the traditional 131I uptake measurement.

Adolescent↗
PubMed1998

Development of a biparametric bioanalyser for creatinine and urea. Validation of the determination of biochemical parameters associated with hemodialysis.

The construction and evaluation of an automated urea and creatinine biparametric biosystem using flow injection analysis (FIA) are described. The biosystem uses enzyme reactions that hydrolyse urea and creatinine producing ammonium ions. The enzymes used were creatinine deiminase and urease, which are immobilized covalently in flow reactors. The reactor with creatinine deiminase has the enzyme immobilized on controlled-pore glass beads, whereas urease is immobilized on a nylon open tubular reactor. Detection is realised with a flow-through ammonium ion-selective electrode with an inner solid-state contact (graphite-epoxy composite). Ammonium ions are separated from alkali ion interferents through a gas-diffusion cell. The bioanalyser is fully automated using software and electronics developed ex profeso in our laboratories. The analyser was validated off-line by measuring urea and creatinine from discrete effluent samples from hemodialysis equipment. Results agreed with concurrent analyses realised using hospital laboratory methods. There were no significant differences between the two sets of results at the 95% confidence level. Finally, the biparametric bioanalyser was validated on-line by measuring creatinine and urea levels in artificial kidney effluents. These measurements were useful in the determination of key biochemical parameters of clinical interest such as the mass of urea and creatinine extracted from the patient as well as the initial concentration of creatinine and urea in blood plasma. When the results of the bioanalyser were compared with those yielded by the usual methods, they showed no significant differences at the 95% confidence level when determining the mass of the analytes extracted by the hemodialyser or when determining the urea concentration in blood plasma. However, when measuring the creatinine concentration in blood plasma using the developed bioanalyser, significant differences appeared.

Biological Assay↗