Print quality assessment

One important outcome of the Hessner et al. studies was development of a method useful for determining microarray spot quality (2003a and 2003b). One of the drawbacks to using microarrays has been how to address quality assurance and quality control (QA/QC) issues regarding the printed product prior to use. After an array is printed, how do you best determine spotting consistency from slide to slide or batch to batch  

The question is similar to asking how many times one can strip and reuse a microarray before performance deteriorates. An alternative approach is provided by Hessner et al. (2003a) in which the cDNA probes are permanently labeled using fluorescein-labeled primers to the clone s vector insert region. Fluorescein is excited at 488 nm and emits at 508 nm, while Cy3 may be excited at 543 nm to reduce any spectral overlap with fluorescein. Thus, fluorescein-labeled cDNA probes may be printed down and the slide scanned for QC/QA purposes prior to hybridization. Since the same region is primer-labeled in each cDNA, a direct comparison between the relahve fluorescence units (RFUs) and the amount of cDNA probe can be defermined. 

Mean S/S + N score 0.85 (S = signal intensity N = noise level) 

A post-printing treatment involving the following sequential rinsing protocol reduced these backgrounds to 200 relative intensity units  

Aging of certain slides (e.g.. Coming GAPS) by exposure to humidified air for several hours prior to printing also reduced the background. It is not known whether this applies to all substrates. 

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Comptroller General of the General Accounting Office. Better Monitoring Techniques are Needed to Assess the Quality of Rivers and Streams, U.S. Government Print Office Washington, D.C., 1981. 

In order to assess the quality of the p53 protein microarrays printed on SAM2 membranes, two different assays are carried out on replica arrays. The antibodybinding assay comprises binding a Cy3-labeled anti-His antibody to the arrayed p53 proteins. This assay is independent of protein activity but provides a measurement of the relative amounts of protein immobilized in each spot. 

Congress of the United States, Office of Technology Assessment. 1988. The Quality of Medical Care Information for Consumers, p. x. Washington, DC U.S. Government Printing Office. 

Other factors to be considered include the effect on disposal of the plastic as a consequence of its being printed. Packaging is an important source of waste for disposal and not only the nature of the plastic but also that of the printing ink used must be assessed with regard to air, soil, and water quality after disposal. 

Reverse-phase protein arrays offer a robust new method of quantitatively assessing expression levels and the activation status of a panel of proteins. For this purpose, the lysate of protein(s) of interest is arrayed without selection via a capture molecule. This array can then be queried with an antibody or ligand probe, or an unknown biological component. Since an individual test sample is immobilized in each array spot, this array can be composed of a variety of different patient samples. Each array is incubated with one detection protein or antibody, and a single end point is measured across the arrayed cohort and can be directly compared across multiple samples. Replicates can be reproducibly printed at a given sitting, increasing quality control over a series of queried arrays (reviewed in [33]). 

Currently informatization of safety quality standardization evaluation work is at low level. Quality evaluation management is characterized by the traditional manual approach. Based on a cloud management platform and mobile terminal can be digitized in management of evaluation content. After input assessment data, the system will automatically generate related evaluation results and statistical information with print function. The system also can be added to the policy query and evaluation method study module at the same time, convenient query management personnel evaluation, improving the efficiency and accuracy of the work. 

Once the print has been jetted on to the cloth, it will dry and can be assessed quickly for quality, although it is not yet ready for use. Different fixing processes are also required, as different ink formulations bond differently with their respective fibers. 

As noted earlier, consulting with mentors and other persons who have experience with particular experiments and instruments is often the best way to learn about safety protocols and details. We list here a few printed resources that also contain useful information. Searching for information online may or may not produce reliable information and it is important to carefully assess the quality of the information. 

However, because of the multitude of existing data of interest to material thermal science and technology, and the variety of modes of presentation, computer-assisted extraction of numerical values of structural data, physicochemical properties and kinetic characteristics from primary sources are almost as difficult as before. As a consequence, the collection of these data, the assessment of their quality in specialized data centei, the publication of handbooks and other printed or electronic secondary sources (compilations of selected data) or tertiary sources (collections of carefully evaluated and recommended data), storage in data banks, and dissemination of these data to end users (educational institutions and basic scientific and applied research centers), still remain tedious and expensive. 

Standards. Review of the National Ambient Air Quality Standards for particulate matter policy assessment of scientific and technical information. OAQPS Staff paper. Research Triangle Park, NC U.S. Government Printing Office, 1996 EPA-452 R-96-013. 

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