System contamination, minimizing

Thermo Nuclean developed the segmented gate system (SGS) to segregate radioactive material from contaminated soil. The SGS is a combined system of conveyors, radiation detectors, software algorithms, and computer controls. The SGS diverts contaminated soil onto a conveyor belt that deposits the soil in a container for disposal or fnrther processing. The developer claims that the system removes minimal amounts of clean soil with the radioactive particles, reducing the amount of material requiring disposal. The SGS is commercially available. 

The product handling and transfer should be carried out in a closed system for minimizing cross-contamination from the environment and from personnel. 

Gawalko and coworkers elucidated the characteristics of closed-vessel and focused open-vessel MW sample preparation techniques for the subsequent determination of Cd, Cu, and Pb, and Se in wheat, wheat products, corn bran, and rice flour by ET-AAS with transverse-heated graphite furnace [23]. Both techniques were evaluated using a total of 15 CRMs for the three food types. In the case of rice, these were the NIES 10a, 10b, and 10c Rice Flour and the NRC Rice Flour. The two techniques were equivalent in terms of agreement with the certified figures. Up to 12 samples could be processed with the closed system with minimal amounts of acid and reduced risk of contamination. Larger masses of samples could be treated by the open-vessel system. 

Due to recent trends in cellular therapy, the pharmaceutical companies have put emphasis on the use of ex vivo electroporation for both DNA and dmg delivery. Using the flow thm system, employing a pump that moves the cell suspension through an electroporation chamber where cells are porated. The entire operation is aimed to a closed system to minimize contamination and facilitate commercial scale cell-processing operations. 

The use of relatively narrow bore tubing for the nitrogen supply system results in a small dead volume in the system, and minimizes contamination when nitrogen tanks are changed, etc. 

FISH or RT-PCR are typically used to detect chromosomal rearrangements. FISH is the method of choice to detect gene rearrangements in FFPE samples, whereas RT-PCR is a reliable and sensitive technique to detect fusion transcripts in snap-frozen samples that can be performed as conventional or real-time RT-PCR. T41-43 Real-time RT-PCR has several significant advantages, as it is fast, is performed in a closed system with minimal risk of contamination, is more specific due to the addition of probes, and allows quantitation of the fusion transcript. 

Sample preparation by means of liquid membrane extraction is a technique that in essence contains two LLE extractions in one step. The setup is easily automated, and sample preparation is performed in a closed system, thus minimizing the risk for contamination and losses during the process. Because the extraction is made from an aqueous phase (donor) to a second, also aqueous phase (acceptor), further enrichment on a precolumn is possible before injection into the LC apparatus. Liquid membranes were used for enrichment of metsulfuron-methyl and chlorsulfuron from clean aqueous samples and natural waters. A similar device was developed by a Chinese... 

Purity of the carrier gas is very important in modern GC equipment designated for trace analysis. Consequently, it is essential that the gas purifiers, such as the traps containing various adsorbents, be inserted in the gas tine before the injection port. The same requirement usually applies for purification of the combustion gases for the flame ionization detector. The role of these adsorbent traps is to remove even the trace quantities of water, oxygen and organic impurities present in commercial gas cylinders, and thus minimize both the system contamination and chemical alteration of an injected sample. 

In manufacturing processes, the use of closed systems to minimize contaminations should be pursued. In such processes, where materials sensitive to microbial contamination may contact contaminated air, appropriate measures shall be taken to prevent the contamination (over pressure, laminar flow cabinets, etc.. 

The outlet nozzle-to-header connectors are of the same size and material as the Inlet connectors. The outlet assembly for each process channel Includes equipment for monltoarLng outlet water temperature and for detecting fuel element cladding failures. Each outlet connector has a remotely operated three-way valve Ich permits diversion of the outlet water from a particular process channel to a contaminated water disposal system to minimize spread of radioactive materials through the primary cooling loop In event of a fuel element failure. 

In many applications, a test vessel modified with an external reference electrode cell has become the most common system to minimize effects of temperature, pressure, or contamination, or a combination thereof, ftom the corrosive environment. This approach helps to prolong the usable life of the reference electrode. One of the most common reference electrode systems used in HT/HP corrosion testing is Ag/AgCl [4]. However, other reference systems have been developed and are used for application in specific environments [5]. The external reference electrode is usually contained in a separate pressurized compartment. The reference electrode is then connected to the test vessel using a bridge or conductive solution conduit. 

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