Quality assurance in the view of a commercial analytical laboratory

 The necessity for analytical quality assurance is primarily a feature of the analytical process itself. With the full establishment of the EU domestic market, it is also becoming a legal necessity for an increasing number of analytical laboratories. The requirements which laboratories will need to fulfil are stipulated in DIN EN 45 001. Accredited testing laboratories must in fact provide evidence that they work solely in accordance with this standard. National and EU commissions, which are legislative authorities, tend therefore to specify analytical methods, e.g. in the form of regulations or appendices thereto, intended to ensure that results from different laboratories will be comparable and hence will stand up in a court of law. The analytical quality assurance system (AQS), introduced by the Baden-Württemberg Ministry for the Environment in 1984, obliges laboratories to regularly participate in collaborative studies and thereby demonstrate their ability to provide suitably accurate analyses. This alone, however, does not sufficiently demonstrate the competence of a laboratory. Only personal appraisal of the laboratory by an auditor, together with the successful analysis of a sample provided by the same and performed under his observation, can provide proof of the competence of the laboratory. From an analytical point of view, the competence of a laboratory must be regarded as the decisive factor. Competence can only be attained through analytical quality assurance, which thus must be demanded of all laboratories. Received: 4 October 1996 Accepted: 15 January 1997     

AT&T准则下完全检验的最优设计(英文)

本文研究了完全检验的质量控制问题,将广泛用于X-控制图的AT＆amp;T准则应用于完全检验,并根据完全检验的特点,提出一种新的最优模型,数值实验结果表明AT＆amp;T准则下的完全检验优于传统的完全检验。     

ESPI solution for non-contacting MEMS-on-wafer testing

Rapid progress in the field of micro-electro-mechanical systems (MEMS) makes the development of appropriate measuring and testing means timely. Characterizing the mechanical properties of MEMS structures at a very early stage of manufacturing is a challenging task for quality assurance in this field. The paper describes a new solution that is based upon the vibration analysis of the microparts. The nanometer amplitudes are detected by advanced electronic speckle pattern interferometry (ESPI). A specific signal processing technique has been applied to make the solution robust. Comprehensive numerical simulations provide the theoretical base for the HNDT concept. A laboratory system for 4″ wafer has been built, and extensive tests show that such key properties as e.g. the thickness of springs or membranes can be determined exactly. Automated frequency scanning and corresponding digital image processing open the way to reliable and fast industrial systems for MEMS testing on wafer level.     

An economic¯X-chart approach to the joint control of the means of independent quality characteristics

Summary In controlling the mean of a multivariate normally distributed quality characteristic the main disadvantage of the globalT ²-control charts is that they don't indicate the component of the quality characteristic which gives rise to an alarm. To avoid this disadvantage the joint use of¯x-charts is proposed in this paper, where — for the sake of simplicity — the investigations are restricted to the case of independent components and to one-sided¯x-charts. On the basis of an economic objective function an approximation to the optimal design of the¯x-charts procedure is derived and discussed. It turns out that at least in the bivariate case the nearly optimal economic design is very close to the exact solution.Supported by the Deutsche Forschungsgemeinschaft (DFG).     

Benchmarking with quality-adjusted DEA (Q-DEA) to seek lower-cost high-quality service: Evidence from a U.S.bank application

Benchmarking is a widely cited method to identify and adopt best-practices as a means to improve performance. Data envelopment analysis (DEA) has been demonstrated to be a powerful benchmarking methodology for situations where multiple inputs and outputs need to be assessed to identify best-practices and improve productivity in organizations. Most DEA benchmarking studies have excluded quality, even in service-sector applications such as health care where quality is a key element of performance. This limits the practical value of DEA in organizations where maintaining and improving service quality is critical to achieving performance objectives. In this paper, alternative methods incorporating quality in DEA benchmarking are demonstrated and evaluated. It is shown that simply treating the quality measures as DEA outputs does not help in discriminating the performance. Thus, the current study presents a new, more sensitive, quality-adjusted DEA (Q-DEA), which effectively deals with quality measures in benchmarking. We report the results of applying Q-DEA to a U.S. bank's 200-branch network that required a method for benchmarking to help manage operating costs and service quality. Q-DEA findings helped the bank achieve cost savings and improved operations while preserving service quality, a dimension critical to its mission. New insights about ways to improve branch operations based on the best-practice (high-quality low-cost) benchmarks identified with Q-DEA are also described in the paper. This demonstrates the practical need and potential benefits of Q-DEA and its efficacy in one application, and also suggests the need for further research on measuring and incorporating quality into DEA benchmarking. The review process of this paper was handled by the Edit-in-Chief Peter Hammer.     

玉帘的组织和原生质体培养

玉帘不同外植体培养，诱导出胚性、中间型和非胚性３种类型的愈伤组织，并再生植株．由胚性愈伤组织与叶肉细胞分离出原生质体，进行培养，启动了细胞分裂并形成了多细胞团．同时，还研究了影响玉帘组织培养以及原生质体分离和培养的诸因素．     

Quality assurance of e-learning in developing countries

In this paper some of the aspects of implementing measures for quality assurance of e-learning in developing countries are discussed. Also the main problems of establishing quality assurance of e-learning are illustrated. The advantages of adopting international measures of quality assurance in those countries together with several recommendations for the future and our conclusion are then given.     

Sensitivity and significance of disease outcome measures in inflammatory bowel disease

In inflammatory bowel disease (IBD), proxy measures of clinical outcome are often collected into summary indices of qualitative self-rated disease markers, clinical observations, and quantitative biochemical analyses. In Crohn's disease (CD), a frequently used index is the Crohn's disease activity index (DCAI). This index consists of six qualitative variables and two quantitative variables. The aim of this presentation is to illustrate the use of this index to calculate its range, to estimate errors in the index, its sensitivity, and the number of significant steps in the index. The measure of sensitivity of the summary index was analyzed for the signal-to-noise ratio (SNR), the reference change value (RCV) and the confidence interval (CI). If identical errors were assumed in patient self-rated health and clinically judged disease manifestations, such as tumours and fistulas, the majority of the variance of the index was caused by the self-rated experience of health, the number of days over which the individual variable was rated, and the prognostic multiplier of each variable.The range of the index has no upper limit, but can be estimated to 403 units, of which patient self-rating of well-being account for up to one-third of the summary index maximal score range. The median signal noise measure of index sensitivity was 18 SDs. The two disease classification limits of 150 units for moderate disease and 450 for severe disease on average cover an interval of limit ±41.5 units vs. ±60.5 units. In judgments on change in clinical outcome the RCV interval of steps of 121 units are valid. Conclusion: Both variance and range of the CDAI summary score are primarily decided by the self-rated experience of well-being. Variables on disease signs have a minor impact on the index. Rating of the two important outcome parameters: Self-experienced health and medical outcome would favourably be given in two individual scores.Presented at the 10th Conference Quality in the Spotlight, March 2005, Antwerp, Belgium.     

A novel quantitative model of cell cycle progression based on cyclin-dependent kinases activity and population balances

Cell cycle regulates proliferative cell capacity under normal or pathologic conditions, and in general it governs all in vivo/in vitro cell growth and proliferation processes. Mathematical simulation by means of reliable and predictive models represents an important tool to interpret experiment results, to facilitate the definition of the optimal operating conditions for in vitro cultivation, or to predict the effect of a specific drug in normal/pathologic mammalian cells. Along these lines, a novel model of cell cycle progression is proposed in this work. Specifically, it is based on a population balance (PB) approach that allows one to quantitatively describe cell cycle progression through the different phases experienced by each cell of the entire population during its own life. The transition between two consecutive cell cycle phases is simulated by taking advantage of the biochemical kinetic model developed by Gérard and Goldbeter (2009) which involves cyclin-dependent kinases (CDKs) whose regulation is achieved through a variety of mechanisms that include association with cyclins and protein inhibitors, phosphorylation–dephosphorylation, and cyclin synthesis or degradation. This biochemical model properly describes the entire cell cycle of mammalian cells by maintaining a sufficient level of detail useful to identify check point for transition and to estimate phase duration required by PB. Specific examples are discussed to illustrate the ability of the proposed model to simulate the effect of drugs for in vitro trials of interest in oncology, regenerative medicine and tissue engineering.