Use Of Quality Index Research Articles

A priori quality assurance using a benchmark case of the randomized phase 2 GORTEC 2014-14 in oligometastatic head and neck cancer patients

PurposeA Benchmark Case (BC) was performed as part of the quality assurance process of the randomized phase 2 GORTEC 2014-14 OMET study, testing the possibility of multisite stereotactic radiation therapy (SBRT) alone in oligometastatic head and neck squamous cell carcinoma (HNSCC) as an alternative to systemic treatment and SBRT. Material and methodsCompliance of the investigating centers with the prescription, delineation, planning and evaluation recommendations available in the research protocol was assessed. In addition, classical dosimetric analysis was supplemented by quantitative geometric analysis using conformation indices. ResultsTwenty centers participated in the BC analysis. Among them, four major deviations (MaD) were reported in two centers. Two (10%) centers in MaD had omitted the satellite tumor nodule and secondarily validated after revision. Their respective DICE indexes were 0.37 and 0 and use of extracranial SBRT devices suboptimal There were significant residual heterogeneities between participating centers, including those with a similar SBRT equipment, with impact of plan quality using standard indicators and geometric indices. ConclusionA priori QA using a BC conditioning the participation of the clinical investigation centers showed deviations from good SBRT practice and led to the exclusion of one out of the twenty participating centers. The majority of centers have demonstrated rigorous compliance with the research protocol. The use of quality indexes adds a complementary approach to improve assessment of plan quality.

Quality indexes based on water measurements for low and medium energy x-ray beams: A theoretical study with PENELOPE

To study the use of quality indexes based on ratios of absorbed doses in water at two different depths to characterize x-ray beams of low and medium energies. A total of 55 x-ray beam spectra were generated with the codes XCOMP5R and SPEKCALC and used as input of a series of Monte Carlo simulations performed with PENELOPE, in which the percentage depth doses in water and the kQ,Q0 factors, defined in the TRS-398 protocol, were determined for each beam. Some of these calculations were performed by simulating the ionization chamber PTW 30010. The authors found that the relation between kQ,Q0 and the ratios of absorbed doses at two depths is almost linear. A set of ratios statistically compatible with that showing the best fit has been determined. The results of this study point out which of these ratios of absorbed doses in water could be used to better characterize x-ray beams of low and medium energies.

A new measure for gene expression biclustering based on non-parametric correlation

BackgroundOne of the emerging techniques for performing the analysis of the DNA microarray data known as biclustering is the search of subsets of genes and conditions which are coherently expressed. These subgroups provide clues about the main biological processes. Until now, different approaches to this problem have been proposed. Most of them use the mean squared residue as quality measure but relevant and interesting patterns can not be detected such as shifting, or scaling patterns. Furthermore, recent papers show that there exist new coherence patterns involved in different kinds of cancer and tumors such as inverse relationships between genes which can not be captured. ResultsThe proposed measure is called Spearman's biclustering measure (SBM) which performs an estimation of the quality of a bicluster based on the non-linear correlation among genes and conditions simultaneously. The search of biclusters is performed by using a evolutionary technique called estimation of distribution algorithms which uses the SBM measure as fitness function. This approach has been examined from different points of view by using artificial and real microarrays. The assessment process has involved the use of quality indexes, a set of bicluster patterns of reference including new patterns and a set of statistical tests. It has been also examined the performance using real microarrays and comparing to different algorithmic approaches such as Bimax, CC, OPSM, Plaid and xMotifs. ConclusionsSBM shows several advantages such as the ability to recognize more complex coherence patterns such as shifting, scaling and inversion and the capability to selectively marginalize genes and conditions depending on the statistical significance.

Evaluating the mechanical properties of a thermomechanically processed unmodified A356 Al alloy employing shear punch testing method

The effects of thermomechanical processing (TMP) parameters on the microstructure evolution and final mechanical properties of an unmodified A356 Al alloy have been investigated. The evaluation of mechanical properties was carried out using shear punch testing (SPT) method. The applied TMP cycles encompassed a set of isothermal hot compression tests in the temperature range of 420–540°C under various strain rates of 0.001, 0.01 and 0.1s−1. The results indicate that increasing both the TMP temperature and strain rate has enhanced the room temperature strength of the experimental alloy. Furthermore, while ductility follows a similar improving trend with increasing the TMP temperature, it is deteriorated by increasing the strain rate. The obtained results are reasoned debating the role of solute atoms and the changes in Si particles shape and size. The present work also made use of quality index (Q) to measure the mechanical performance of the TMPed unmodified A356 Al alloy.

Quality indices for (practical) clustering evaluation

Clustering quality or validation indices allow the evaluation of the quality of clustering in order to support the selection of a specific partition or clustering structure in its natural unsupervised environment, where the real solution is unknown or not available. In this paper, we investigate the use of quality indices mostly based on the concepts of clusters' compactness and separation, for the evaluation of clustering results (partitions in particular). This work intends to offer a general perspective regarding the appropriate use of quality indices for the purpose of clustering evaluation. After presenting some commonly used indices, as well as indices recently proposed in the literature, key issues regarding the practical use of quality indices are addressed. A general methodological approach is presented which considers the identification of appropriate indices thresholds. This general approach is compared with the simple use of quality indices for evaluating a clustering solution.

Effects of aging parameters on the quality of 413-type commercial alloys

The use of quality indices and charts to determine the quality of aluminum alloys in terms of their mechanical properties has gained prominence in recent times, although studies reported in the literature have concentrated mainly on Al–Si–Mg and Al–Si–Mg–Cu systems. Eutectic Al–Si alloys such as the 413 alloys investigated in this study are another important class of aluminum alloys used in industrial applications. In view of the lack of similar investigations in the case of these alloys, a detailed analysis of the quality of 413-type alloys using different quality indices was carried out, based on the mechanical properties obtained as a result of the use of chemical modifiers, alloying element additions and heat treatment conditions. Results reveal that the quality maps obtained provide a simple means for selecting the most suitable alloy chemistry and aging conditions in 413-type casting alloys for a given application. Based on the best possible compromise between alloy performance (i.e., mechanical properties) and optimum quality, recommendations may be made for selecting the necessary heat treatment conditions for specific alloy compositions.

Use of quality indices in comparison of corroded technical steel bars B500c and S500s on their mechanical performance basis

The nominal cross-sectional area-based quality index Q D has been utilized to evaluate and compare the mechanical performance of steel grades B500c and S500s. Although when uncorroded B500c has better mechanical performance than S500s, after 60 days of accelerated corrosion exposure, quality index values of B500c drop significantly below the respectives of S500s. Responsible for this behavior is localized corrosion damage detected in B500c steel bars only. The constant improvement of the mechanical properties of concrete reinforcing steel bars by neglecting the long time effect of corrosion may lead to unexpected results in the long run. A revision of the standards such as to account for corrosion effects on the material properties seems to be imperative.

Use of Quality Index in the Evaluation of Organ Procurement and Transplant Programs in a University Hospital

Aim To evaluate organ procurement efficiency at Hospital Clinic of Barcelona (HCP), a University Hospital, in 2000 and 2003 compared with other Catalan, other Spanish, and American (US) results. Methods Efficacy rate of the donor procurement was calculated per million population per year (pmp/y). Efficacy rate in kidney, liver, and heart transplantation was calculated also in pmp/y. We evaluated 1-year graft survival. Results During this period, the average rate number of donors was 49.1 pmp/y in HCP, 38 in Catalonia, 33.4 in Spain, and 21.7 in the United States. The average rate of kidney transplantation was 74 pmp/y in HCP, 55 in Catalonia, 47 in Spain, and 24.6 in the United States. The average rate of liver transplantation was 44.5, 26.6, 23.2, and 18 pmp/y, respectively. The average rate of heart transplantation was 13.3, 8.5, 7.8, and 6.4 pmp/y, respectively. One-year graft survival in HCP was 90.6% for kidney, 89.5% for liver, and 88.2% for heart transplants. Discussion The results show that organ procurement and transplantation programs in HCP are efficient. The organizational model is based on a hospital transplant coordinator and efficient, well-trained transplant teams.

Generation of quality maps to support material selection by exploiting the quality indices concept of cast aluminum alloys

The use of quality indices of cast aluminum alloys to support material selection by means of generation of quality maps was investigated. The quality indices are methods for quality evaluation of cast aluminum alloys that evaluate the material on the basis of its mechanical performance. Quality maps were generated to support the material selection, on the basis of all proposed quality indices, devised for the evaluation of cast aluminum alloys to be used in aircraft applications. Produced quality maps provide the design engineer a tool to estimate a quality plateau, where lies all the candidate materials to be used for the specific application. Quality maps allow for comparison with all aluminum alloy systems. They also allow for a systematic assessing of the effect of chemical composition, solidification rate and heat treatment on the mechanical performance of the material. Use of such quality maps enables the design engineer to quick select the candidate materials of high quality (optimized mechanical performance) in order to maximize the quality of the structure.

A Comparison of School-Based Intervention Teams: Implications for Educational and Legal Reform

This study examined the practices of school-based intervention teams. Six hundred and eighty professionals, representing 121 intervention teams from Michigan, Illinois, and Wisconsin, participated in the study. Team members and problem identifiers (who brought at least one case to the team) completed a survey investigating (a) the nature of referrals addressed by the team, (b) perceptions of team effectiveness, (c) identification of professionals who best facilitate team problem-solving via their knowledge and communication skills, and (d) use of quality indices in intervention development and implementation. Findings revealed several positive practices by teams from all states. However, teams from Illinois displayed consistent superiority across several measures. Discussion focuses on implications for practice and educational and legal reform.

Prereferral interventions: Quality indices and outcomes

Quality indicators of prereferral interventions (i.e., behavioral definition, direct measure, step-by-step plan, treatment integrity, graphing of results, and direct comparison to baseline) were investigated as predictors of prereferral intervention outcomes with a sample of regular education teachers and related services personnel on the same 312 students. The majority of the prereferral interventions were deficient in these critical areas; however, the presence of quality indices was related to positive student outcomes. The results suggested that (a) prereferral interventions varied dramatically in quality, (b) the use of quality indices influenced the outcomes of prereferral interventions, and (c) improved quality of interventions led to more successful outcomes for students.