Glass bead columns

Benzene Glass bead column 5 ml nitrating acid 0.25 3-5 + 95 Butanone method Other aromatic... 

Commercial dicyclopentadiene (b.p. 170°) is placed in a flask and boiled to crack the dimer to the monomer. A 20-cm. glass-bead column permits taking relatively pure... 

One hundred grams of store bought string beans extracted with methylene chloride, were concentrated to 10 ml, and 0.5 ml equivalent to 5g of beans was placed on the glass bead column and eluted with methylene-chloride+2-propanol solution. This extract showed a peak corresponding to 1.5 ng of malathion. 

Scale-up of cell cultures makes use of suspension cultures (erythropoietic cells or microcarriers) or, less often use of capillary beds (hollow fibre systems or glass bead columns), but these suffer from the same disadvantages seen with smaller scale cultures ( 3.4.4). In particular, nutrients are depleted as the medium flows through long columns or beds and high rates of flow coupled with recirculation are often employed. Nevertheless, Organon have used a hollow fibre dialysis system for production of monoclonal antibodies (Schonherr et al., 1985). Invitron s hollow fibre system has been used to produce cell conditioned media and the Cell-Pharm System (Jencons Ltd. Appendix 3) will produce up to 20 g cell secreted product per month. 

Two different methods are in general use the glass bead column method of Rabinowitz (1964, 1973) and the density gradient centrifugation method of Boyum (1968). 

Fig. 6.1. DNA synthesis in PHA-stimulated horse lymphocytes. Aliquots of 3x10 horse lymphocytes purified by the glass bead column method were incubated for various lengths of time with PHA-M in tubes in 3 ml Eagle s MEM (supplemented with 10 fig serine/ml and 7.5 fig glycine/ml and 10% autologous horse plasma). Before harvesting the cells were labelled for 6 h with [14C]thymidine (3.66 Ci/mol 1 fiCi/ml). o, Amethopterin (10 6M) was added 16 h before harvesting. , no amethopterin added. (Courtesy of Dr. B.S. Zain, 1971.)...

Platelet retentim in glass bead columns for Wistar rat platelets is similar to that for human platelets. 

Guard column 21 x 3 40 xm glass bead column (Waters)... 

Improving separation in GSC is largely a matter of decreasing the contribution of gas phase mass transfer to HETP. As in the case of liquid-solid systems, the Cv term is proportional to adsorbent particle diameter squared, so it is advantageous to work with small particles, fn packed columns a decrease in particle size is accompanied by an increase in resistance of the bed to gas flow, which tends to offset the separation advantage of fine particle beds. This effect can be offset to some extent by using packed capillaries, coated capillaries, or coated glass bead columns (5-7 ). 

Generally in commercial apparatus, no device is used to prevent solvent back--flow. In the Perkin-Elmer system, a small glass bead column is used on each solvent line to limit this back-flow to the reservoir, but it cannot prevent it completely. The Varian pumps can be supplied with a pneumatic valve which suppresses back-flow and reduces the inconveniences. 

Figure K Structure of polyalkyl acrylates and methacrylates. Polymers were synthesized by free radical polymerization Initiated by exposing alkyl acrylate and methacrylate monomers to high doses ( 10 Mev) of ionizing radiation using a Van de Graff accelerator. Polymers were separated from unreacted monomer by precipitating in methyl alcohol and redissolving in chloroform. Purified polymers were dissolved in chloroform for use in coating glass beads columns and glass cover slips.

A second series of experiments utilizing glass bead columns was designed so that adsorbed fibrinogen could be eluted in stages... 

Figure 5. SDS-polyaerylamide gel electrophoresis (reducing conditions) of fibrinogen after elution from glass bead column.

Figure 6. Comparison of plasmin degradation products with glass bead column eluate of fibrinogen.

Sodium hydroxide solution is a frequently used mobile phase in the aqueous starch SEC system. The concentrations range from 0.005 to 0.5 N. The optimum concentration may depend on the packing material used. In aqueous SEC for sulfonated polystyrene, sodium sulfate in the mobile phase can be as high as 0.8 M for porous glass bead columns (56). For Bondagel or Aquapore columns, the salt concentration must below 0.05 M (57). 

Platelet retention in glass bead columns Reversal of adenine nucleotide-induced inhibition by apyrase. Fed. 

Coller, B. S., and Zucker, M. B. Reversible decrease in platelet retention by glass bead columns ( adhesiveness ) induced by disturbing the blood. Proc. Soc. Exp. Biol. 

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