Clumping tendency

Aggregation of blood platelets is the requisite first event for the maintenance of intact circulation in the face of any break in a blood vessel. It is the platelet clump that starts the long and complicated process leading to closure of the broken vessel by an organized blood clot. Though this property of platelets is vital to maintenance of the circulatory system, an excessive tendency to aggregation can also lead to problems. Thus platelet clumps formed in blood vessels in the absence of injury can lead to blockade of blood circulation and subsequent injury. Strokes and some types of myocardial infarcts have thus been associated with platelet clumps. The nonsteroid antiinflammatory... 

After fixation, it is usually best to stain and run the samples as soon as possible, and certainly within a few days, since there is evidence to suggest that some proteins are susceptible to degradation in longer-term storage. With the enucleated samples, there is a tendency for further clumping to occur in storage. 

Frozen spleen cells work well for cell fusions and this approach allows a greater degree of flexibility in performing fusions than using splenocytes directly ex vivo. The vial of spleen cells should be rapidly thawed in a 37 °C water bath or between the palms of the hands. One milliliter of PBS is then added to the vial and the contents aspirated and added to 5 mL of PBS. The cells are washed once by centrifugation at 400g and resuspended in 5 mL of cold PBS they should then be stored on ice until required. Spleen cells that have been frozen may have a tendency to clump and the pellet will look very pale. This does not affect their ability to produce viable hybridomas. 

The state of aggregation of the flowing material, its tendency to clump, and for a group of molecules to move about together. 

As the cell density increases there is often a tendency for microcarriers to begin clumping. This can be avoided by increasing the stirring speed to 75-90 rpm. 

Care must be taken not to overtrypsinize the cells when removing them from the tissue culture surface. The 2.2.15 cells are sticky and have a natural tendency to clump. Aggregated cells do not grow well and are difficult to count. The 2.2.15 cells also perform better in reseeding and cryopreservation procedures if they receive fresh medium 24 h before trypsinization. 

As is the case with ceramic sintering, joining, and powder synthesis, microwave-assisted fabrication of ceramic coatings can offer unique benefits. To expose the material surfaces for reaction with a gas phase, fibers or powder particles may be suspended by the flow of gas in the fluidized bed. In addition to the flow of the fluidizing gas, low frequency mechanical vibrations (for example, 10-15 Hz) may be applied to the container to reduce the tendency for the powders or fibers to sinter together to form clumps. As the powder size decreases, the powder s sinterability increases. While vibration may not be necessary for particles as large as, say, 50 pm, it may be beneficial for powder particles that are a few microns in diameter. 

Another difficulty encountered is the tendency of Rhizopus sporangiospores to grow into mycelial mats or mycelial clumps. The growing mycelia will anchor onto the inside elements of the reactor such as the bafflers, propellers, and heat exchanger (see Fig. 10, unpublished observation). This results in the inter-... 

When we look at the residuals carefully, we are likely to find unexpected appearances. This seems to be true in our example here. Table 6 gives us a rather hard look at two sets of residuals, both of which seem to show some tendency toward relatively regular clumping. Inquiry of Dr. Lide as to whether there was a least count of 0.04 cm"1 to 0.05 cm"1 (40 or 50 in the units of Table 5) in the wave numbers either in measurement or calculation brought a response that this was not to be ruled out. While the discovery of such an effect at the time when the data were being analyzed might have been quite helpful, neither the suggestion nor a possible proof of its existence today can be of importance. 

Depending on stoppering equipment and tendency of stoppers to clump during sterilization, a silicone lubricant may be added to the stoppers prior to sterilization. Several manufacturers offer equipment which is capable of all these operations-washing, silicone addition, and sterilization. 

At the isoelectric point the protein molecules no longer have a net surface charge. As a result they no longer strongly repel one another and are at their least soluble. Under these conditions, there is a tendency for them to clump together and precipitate out of solution. In this case, proteins may coagulate even though they are not denatured. 

Unfortunately, most phosphites have a tendency to hydrolyze in the presence of moisture, causing clumping, handling and feeding problems, and potentially black specks in the resin. However, pentaerythritol-based phosphites are effective for stabilizing POs, and these reportedly have overcome some problems with hydrolysis [3-2, 3-5, 3-9, 3-12],... 

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