Accuracy Of Available Methods Research Articles

Comparison of Colistin Susceptibility Tests

Introduction: Polymyxins are important antimicrobial agents for the treatment of infections caused by Gram-negative bacteria. The susceptibility testing for polymyxins is a challenge for clinical laboratories due to the difficulty of performance, reproducibility, and accuracy of available methods. Aim: To compare the performance of the colistin susceptibility test of an automated system and a gradient test with the gold standard broth microdilution method (BMD). Materials and Methods: Multidrug-resistant isolates of Acinetobacter baumannii (n=102), Klebsiella pneumoniae (n=40), and Pseudomonas aeruginosa(n=11) were included. The VITEK 2 systems and gradient test were studied according to the manufacturer’s instructions. Broth microdilution tests were performed according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Commercial susceptibility testing methods were compared to BMD. Results: Rates of essential agreement of colistin test results between BMD, VITEK 2, and gradient test were 96.1% and 79.7%, respectively. The VITEK 2 and gradient test showed 95.4% and 94.8% of categorial agreement. The very major error rate of VITEK 2 was 3.2%, and the gradient test was 5.2%. The major error rate of VITEK 2 was 1.3%, and there was no major error for the gradient test. Conclusion and Suggestions: The very major error rate was higher in the gradient test (5.2%) than VITEK 2 (3.2%). Even if the very major error rate of VITEK 2 was lower, both resistance and susceptility results of VITEK 2 should be confirmed with the BMD test. Further studies for susceptibility testing are needed with a focus on the correlation of MIC’s results of different tests.

Wall-diaphragm interactions in seismic response of single-story building systems

The objective of this paper is to investigate the seismic time history response of single-story buildings with a wide range of wall and roof diaphragm periods and ductility. Current design specifications, e.g., ASCE 7-16, are transitioning from accounting for inelasticity in only the vertical lateral force resisting systems, i.e., the walls, to including inelasticity in the horizontal lateral force resisting system, i.e., the roof diaphragm. It is not clear if the wall and roof inelasticity can be considered independently, nor if they can utilize their own seismic response modification coefficients. More fundamentally, the basic manner in which stiffness, mass, and ductility of the wall and roof interact is not fully understood. Here, a single-story building is approximated with a reduced order mass-spring model and parameters are varied so that a wide range of wall periods, diaphragm periods, and wall and diaphragm inelasticity are explored. The model is imposed to vibration analyses, elastic time history analyses, and inelastic time history analyses. The results show clear regimes where the wall and diaphragms interact, and those where the response is largely independent. When inelasticity occurs the ductility demands can be significant for the building component, wall or diaphragm, that initiates the yielding, and greater than traditionally expected. The model results are compared to current and proposed provisions for predicting force and ductility demands and conclusions are drawn with respect to the accuracy of available methods.

Robust correlation dimension estimator for heart rate variability

Introduction. Non-linear methods of analysis have found widespread use in the Heart Rate Variability (HRV) technology, when the long-term HRV records are available. Using one of the effective nonlinear methods of analysis of HRV correlation dimension D2 for the standard 5-min HRV records is suppressed by unsatisfactory accuracy of available methods in case of short records (usually, doctors have about 500 RRs during standard 5-min HRV record), as well as complexity and ambiguity of choosing additional parameters for known methods of calculating D2. The purpose of the work. Building a robust estimator for calculating correlation dimension D2 with high accuracy for limited se-ries of RR-intervals observed in a standard 5-minute HRV record, i. e. with N  500. As well as demonstrating the capabilities of the D2 formula on a well known attractors (Lorenz, Duffing, Hennon and etc.) and in applications for Normal Sinus Rhythm (NSR), Congestive Heart Failure (CHF) and Atrial Fibrillation (AF). Materials and Methods. We used MIT-BIH long-term HRV records for normal sinus rhythm, congestive heart failure and atrial fibrillation. In order to analyze the accuracy of new robust estimator for D2, we used the known theoretical values for some famous attractors (Lorenz, Duffing, Hennon and etc.) and the most popular Grassberger-Procaccia (G-P) algorithm for D2. The results of the study. We have shown the effectiveness of the developed D2 formula for time series of limited length (N = 500–1000) by some famous attractors (Lorenz, Duffing, Hennon and etc.) and with the most popular Grassberger-Procaccia (G-P) algorithm for D2. It was demonstrated statistically significant difference of D2 for normal sinus rhythm and congestive heart failure by standard 5 min HRV segments from MIT-BIH database. The promised technology for early prediction of atrial fibrillation episodes by current D2 algorithm was shown for standard 5 min HRV segments from MIT-BIH Atrial Fibrillation database. Conclusion. Robust correlation dimension D2 estimator suggested in the article allows for time series of limited length (N ≈ 500) to calculate D2 value that differs at mean from a precise one by 5 ± 4%, as demonstrated for various well known attractors (Lorenz, Duffing, Hennon and etc.). We have shown on the standard 5-min segments from MIT-BIH database of HRV records: - the statistically significant difference of D2 for cases of normal sinus rhythm and congestive heart failure; - D2 drop significantly for the about 30 min. before of AF and D2 growth drastically under AF there was shown for HRV records with Atrial Fibrillation (AF) episodes. The suggested robust correlation dimension D2 estimator is perfect suitable for real time HRV monitoring as accurate, fast and non-consuming for computing resources. Key words: Hearth rate variability; Correlation dimension; Congestive heart failure; Atrial fibrillation.

Relationships among compressive strength and UPV of concrete reinforced with different types of fibers

This paper determines the effect of steel, glass, and nylon fibers on the compressive strength and ultrasonic pulse velocity (UPV) of fiber reinforced concrete. The influence of different fiber types, fiber volume fraction, and water to cement ratios on the compressive strength of fiber reinforced concrete was tested using the compression test machine (CTM) and ultrasonic pulse velocity tester. Experiments were carried out at different ages on more than 100 cylindrical specimens. A comparison between the experimental results and equations available in the literature for prediction of compressive strength in terms of UPV was conducted to better evaluate the accuracy of available methods, when the type and volume fraction of fibers change. A new empirical equation that accounts for the presence of different types of fibers and fiber volume fraction is proposed to better estimate the compressive strength of steel, glass, and nylon fiber reinforced concrete.

FLT3mutation Assay Laboratory Cross Validation: Results from the CALGB 10603/Ratify Trial in Patients with Newly Diagnosed FLT3-Mutated Acute Myeloid Leukemia (AML)

FLT3mutation Assay Laboratory Cross Validation: Results from the CALGB 10603/Ratify Trial in Patients with Newly Diagnosed FLT3-Mutated Acute Myeloid Leukemia (AML)

Factor of safety of slope stability from deformation energy

The factor of safety of a slope (Fs) is invariably assessed using methods underpinned by moment, force, and (or) shear strength equilibrium concerning slip surfaces. Each method inherently embeds some form of limitations, despite being popularly adopted in practice. In this paper, a new Fs is devised using the ratio of ultimate energy (eu, upon sliding) over accumulated “elastic” energy. The Fs is then reduced to a simple expression of the power to shear stress and shear strength, by taking soil as an elastic–plastic material obeying the Mohr–Coulomb failure criterion. This expression empowers significant efficacy in gaining the factor of safety (without involving energy or directions of shear stresses). The Fs values were calculated for three typical slopes concerning various mechanical properties (dilation, Poisson’s ratio, and shear modulus) and effective computational strategies. All of the Fs values (to a congruous accuracy of available methods) were obtained in less than 1% the time of conventional numerical analyses. The proposed Fs, equally applicable to limit equilibrium methods, may be utilized in practice to expedite slope design.

Use of Biomarkers in Irritable Bowel Syndrome: To Predict the Future, Look at the Past.

Use of Biomarkers in Irritable Bowel Syndrome: To Predict the Future, Look at the Past.

Systematic review with meta-analysis: the accuracy of diagnosing irritable bowel syndrome with symptoms, biomarkers and/or psychological markers.

Irritable bowel syndrome (IBS) is a complex, heterogeneous disease which can be challenging to diagnose. No study has identified and assessed the accuracy of all available methods of diagnosing IBS. To conduct a systematic review of the literature to identify and assess accuracy of symptom-based diagnostic criteria, biomarkers, psychological markers or combinations thereof. MEDLINE, EMBASE and EMBASE Classic were searched (until April 2015) to identify studies reporting accuracy of available methods to diagnose IBS in adult populations. Eligible studies assessed accuracy of these diagnostic tests against an accepted reference standard. Data were extracted to calculate positive and negative likelihood ratios, with 95% confidence intervals (CIs), of the diagnostic test utilised. Where more than one study used the same test, data were pooled in a meta-analysis. Twenty-two studies (7106 patients) were eligible. Positive and negative likelihood ratios of the current gold standard, the Rome III criteria, were 3.35 (95% CI: 2.97-3.79) and 0.39 (95% CI: 0.34-0.46), similar to other symptom-based criteria. Eleven biomarkers performed no better than symptom-based criteria. Psychological markers performed well in one study. Five different combinations were assessed. The best in terms of positive likelihood ratio was faecal calprotectin, intestinal permeability and Rome I criteria (26.4; 95% CI: 11.4-61.9), and in terms of negative likelihood ratio serum-based biomarkers and psychological markers (0.18; 95% CI: 0.12-0.25). Symptom-based diagnostic criteria, biomarkers and psychological markers performed modestly in predicting IBS. Combining symptoms with markers appears more effective, and may represent the way forward in the diagnosis of IBS.

Who is this person? A comparison study of current three-dimensional facial approximation methods

Facial approximation is a common tool utilised in forensic human identification. Three-dimensional (3D) imaging technologies allow researchers to go beyond traditional clay models to now create virtual computed models of anatomical structures. The goal of this study was to compare the accuracy of available methods of facial approximation ranging from clay modelling to advanced computer facial approximation techniques. Two computerised reconstructions (FaceIT and FBI's ReFace) and two manual reconstructions (completed by FBI's Neville and Faraut) were completed using a skull from a known individual.A living individual's computed tomography (CT) scan was used to create a virtual 3D model of the skull and soft tissue of the face. The virtual skull models were provided to the computer-based approximation specialists. A rapid prototype of the skull was printed and provided to the practitioners who needed physical specimens.The results from all of the methods (clay and virtual) were compared visually to each other and collectively to the actual features of the living individual to compare the results of each. A quantitative study was also conducted to establish the accuracy of each method and the regions of the face that need the most improvement for all of the specialists.This project demonstrates the wide range of variation between commonly used facial identification methods. The benefit of this study was having a living individual to test the strengths and weaknesses of each method while also providing future areas of focus for soft tissue depth data studies.

Ultrasound elastography in the follow-up of a superficial vein thrombosis: a case report

Purpose: To depict the potential role of ultrasound elastography in the follow-up of a peripheral vein thrombosis. Method: A case report of a patient with thrombosis of the jugular vein examined sequentially by B-mode ultrasonography and ultrasound elastography. Results: Common treatment methods in the case of a venous thrombosis include medication with anticoagulants or surgical thrombectomy. Since the treatment succeeds only during the first 7–10 days, the age determination of a trombosis is of high importance for an appropriate treatment decision. However, the accuracy of available methods including sonography, phlebography, CT and MRT is often not sufficient. Blood clots leading to venous thrombosis undergo an organization process with increasing age. It is known that changes in mechanical stiffness, acoustical properties and appearance in B-mode images accompany the organization process. Therefore it should be possible to use elastography to stage the degree of organisation and thereby determine the age of venous thrombi. In this work, we ilustrate a case of a superficial thrombosis studied by B-mode ultrasonography and elastography formed in a jugular vein. The patient undergo no treatement and the vein was studied a few days after the clinical symptoms and a month after the vein was first studied. The use of elastography is revealed in the changes visualised using this method. Conclusion: Ultrasound elastography can be useful in the evaluation of the age of a thrombus.

Comparison of Evapotranspiration Estimates by NOAA-AVHRR Images and Aircraft Flux Measurements in a Semiarid Region of Spain

Abstract This paper is intended to show how to aggregate two different remote-sensing techniques carried out in the framework of the European-Union funded project EFEDA (European Field Experiment in a Desertification-threatened Area). One of these is based on satellite measurements, and the other on aircraft flux measurements. The aim of putting together both methodologies was to determine regional evapotranspiration as a major component of the water balance in Castilla-La Mancha, a semiarid region in southeast Spain. The basis for the satellite approach is using temperature information collected by the Advanced Very High-Resolution Radio- meter (AVHRR) sensor on board the National Oceanic Atmosphere Administration (NOAA) satellite to derive reference and actual evapotranspiration estimates, extending and applying results previously achieved by the present authors. The aircraft measurements make use of the principles of turbulent water vapour transport in the lowest layer of the atmosphere, processing information about the spatial variability of energy and evaporation fluxes along several flight paths across the area, allowing an evapotranspiration measurement useful to validate satellite estimates. The differences between these methods are below 1 mm/d, which is within the range of the accuracy of available methods for estimating surface fluxes on a regional scale.