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Quality Control Systems (quality + control_system)
Selected AbstractsA review of current developments in process and quality control for injection moldingADVANCES IN POLYMER TECHNOLOGY, Issue 3 2005Zhongbao Chen Abstract Injection molding is one of the most versatile and important manufacturing processes capable of mass-producing complicated plastic parts in net shape with excellent dimensional tolerance. Injection molding process and quality control has been an active research area for many years, as part quality and yield requirements become more stringent. This paper reviews the state-of-the-art research and development in injection molding control. It organizes prior studies into four categories, namely, process setup, machine control, process control, and quality control, and presents the distinction and connection of these different levels of control. This paper further reviews and compares the typical variables, models, and control methods that have been proposed and employed for those control tasks. Strictly speaking, real online quality control without human intervention has yet to be realized, primarily due to the lack of transducers for online, real time quality response measurement, and a robust model that correlates the control variables with quantitative quality measurements. Based on the research progress to date, this paper suggests that the different levels of control tasks have to be integrated into a multilevel quality control system, and that the quality sensor and the process and quality model are the two most important areas for further advancement in injection molding control. © 2005 Wiley Periodicals, Inc. Adv Polym Techn 24: 165,182, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20046 [source] Exploration of oligosaccharide-protein interactions in glycoprotein quality control by synthetic approachesTHE CHEMICAL RECORD, Issue 6 2006Shinya Hagihara Abstract High-mannose-type oligosaccharides, which are cotranslationally introduced to nascent polypeptides, play important roles in glycoprotein quality control. This process is highly complex, involving a number of lectins, chaperones, and glycan-processing enzymes. For example, calnexin and calreticulin (CRT) are molecular chaperones that recognize monoglucosylated forms of high-mannose-type glycans. UDP-glucose,:,glycoprotein glucosyltransferase (UGGT) only glucosylates high-mannose-type glycans attached to partially folded proteins. Fbs1 is a component of ubiquitin ligase that recognizes sugar chains. Although recent studies have clarified the properties of these proteins, most of them used oligosaccharides derived from natural sources, which contain structural heterogeneity. In order to gain a more precise understanding, we started our program to comprehensively synthesize high-mannose-type glycans associated with a protein quality control system. Additionally, investigation of artificial glycoproteins led us to the discovery of the first nonpeptidic substrate of UGGT. These synthetic oligosaccharide probes have allowed us to conduct quantitative evaluations of the activity and specificity of CRT, Fbs1, and UGGT. © 2007 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 290,302; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20088 [source] Mutation analysis in mitochondrial fatty acid oxidation defects: Exemplified by acyl-CoA dehydrogenase deficiencies, with special focus on genotype,phenotype relationshipHUMAN MUTATION, Issue 3 2001Niels Gregersen Abstract Mutation analysis of metabolic disorders, such as the fatty acid oxidation defects, offers an additional, and often superior, tool for specific diagnosis compared to traditional enzymatic assays. With the advancement of the structural part of the Human Genome Project and the creation of mutation databases, procedures for convenient and reliable genetic analyses are being developed. The most straightforward application of mutation analysis is to specific diagnoses in suspected patients, particularly in the context of family studies and for prenatal/preimplantation analysis. In addition, from these practical uses emerges the possibility to study genotype,phenotype relationships and investigate the molecular pathogenesis resulting from specific mutations or groups of mutations. In the present review we summarize current knowledge regarding genotype,phenotype relationships in three disorders of mitochondrial fatty acid oxidation: very-long chain acyl-CoA dehydrogenase (VLCAD, also ACADVL), medium-chain acyl-CoA dehydrogenase (MCAD, also ACADM), and short-chain acyl-CoA dehydrogenase (SCAD, also ACADS) deficiencies. On the basis of this knowledge we discuss current understanding of the structural implications of mutation type, as well as the modulating effect of the mitochondrial protein quality control systems, composed of molecular chaperones and intracellular proteases. We propose that the unraveling of the genetic and cellular determinants of the modulating effects of protein quality control systems may help to assess the balance between genetic and environmental factors in the clinical expression of a given mutation. The realization that the effect of the monogene, such as disease-causing mutations in the VLCAD, MCAD, and SCAD genes, may be modified by variations in other genes presages the need for profile analyses of additional genetic variations. The rapid development of mutation detection systems, such as the chip technologies, makes such profile analyses feasible. However, it remains to be seen to what extent mutation analysis will be used for diagnosis of fatty acid oxidation defects and other metabolic disorders. Hum Mutat 18:169,189, 2001. © 2001 Wiley-Liss, Inc. [source] On-line monitoring and fingerprint technology: new tools for the development of new catalysts and polyolefin materialsMACROMOLECULAR SYMPOSIA, Issue 1 2004Arno Tuchbreiter Abstract The High-Output Polymer Screening (HOPS) combines process-relevant automated reactor systems and rapid polymer characterization with on-line polymerization monitoring and automated data acquisition ("electronic notebook") in order to make effective use of advanced data mining tools. This has led to the development of fingerprint technology based upon correlations between spectroscopic data and polymerization process conditions, catalyst compositions, as well as polymer end-use properties. Infrared spectroscopic fingerprints proved to be very useful for accelerating polymer analyses including characterization of polymer molecular architectures as well as non-destructive testing of the mechanical, thermal and other end-use polymer properties. Such spectroscopic fingerprints represent important components of effective on-line quality control systems. With ATR-FT-IR probes on-line monitoring of catalytic olefin copolymerization was performed in solution to measure in real time copolymerization kinetics, catalyst productivities, catalyst deactivation as well as copolymerization parameters and copolymer sequence distributions. Monomer consumption and comonomer incorporation were monitored simultaneously. Advanced fingerprint technology can reduce significantly the need for time- and money consuming polymer testing and can also stimulate the search for new catalyst systems and polymeric materials. [source] A laboratory and clinical evaluation of single-use instruments for tonsil and adenoid surgeryCLINICAL OTOLARYNGOLOGY, Issue 2 2005A. Tomkinson Objectives:, To compare the quality and consistency of single-use adenotonsillectomy instruments available in the UK with reusable instruments and examine their performance in a clinical setting. Design:, A laboratory assessment of each reusable instrument created a detailed specification for the respective single-use equivalent. A surveillance system monitored the performance of a selected set of specified single-use instruments. Setting:, Single-use instruments were withdrawn shortly after their introduction in 2001. Persisting concerns from the Spongiform Encephalopathy Advisory Committee led to an investigation into the feasibility of continuing to use such instruments. Main outcome measures:, The numbers of instruments from each set judged as unacceptable or as good as the original. The number and cause of instrument failure during clinical surveillance. Results:, Between 40% and 93% of the instruments on each set were as good as the original and between 0% and 40% of the instruments were unacceptable from six sets of steel and one set of polymer instruments. 4151 procedures were monitored between 1 February 2003 and 31 March 2004 using a total of 41 376 instruments. Problems were reported with 335 (0.8%) instruments, 46% attributable to instrument design, 14% to poor design control and 13% to instruments escaping quality control systems. Following correction of the faults, between 1 January 2004 and 31 March 2004 the problem rate fell to 0.4%. Conclusions:, High quality single-use instruments for tonsil and adenoid surgery are available in the UK. Some companies offered inferior instruments not fit for their purpose. The procurement, introduction and subsequent clinical approval of single-use instruments requires a radically different approach to that currently applied to the purchase of reusable surgical equipment. Careful monitoring of their introduction is essential. [source] | ||||||||||