Composite polymer membrane of polyvinyl alcohol (PVA) and acrylamide was prepared on cheesecloth support by gamma-irradiation induced free radical polymerization. The enzyme urease was entrapped in the membrane during polymerization and was cross-linked within the matrix using glutaraldehyde. The membranes could be reused a number of times without significant loss of urease activity.

Enzymes which possess the ability to cause the adherence of Streptococcus mutans cells to a smooth glass surface were purified 1,100 times by chromatography on agarose gel followed by hydroxylapatite gel. During the purification procedures, the enzymes from strain HS6 (group a) were examined for the synthesis of water-soluble and water-insoluble polysaccharide and the ability to produce adheren...

This paper describes the application of a bifunctional polyacrylamide (pA-V-F) presenting both vancomycin and fluorescein groups, to modify the surfaces of multiple species of Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Enterococcus faecalis) to control molecular recognition of these surfaces. The vancomycin groups allowed the specifi...

Cross-linked polymer hydrogels, polyacrylamide co-polymer (XPAM) or polyacrylate (XPAA) offer potential solutions for soil degradation, declines in resilience, and poor productivity marginal soils. However, little is known about their long-term effect on nutrient availability. This 9-yr, irrigated, outdoor, cropped pot study evaluated a single, one-time addition of XPAM XPAA at 0.25 0.5% dry wt...

We study the necking and pinch-off dynamics of liquid droplets that contain a semidilute polymer solution of polyacrylamide close to overlap concentration by combining microfluidics and single DNA observation. Polymeric droplets are stretched by passing them through the stagnation point of a T-shaped microfluidic junction. In contrast with the sudden breakup of Newtonian droplets, a stable neck...

A hydrogel was prepared by crosslinking aqueous solutions of sulfonated polyacrylamide/chromium triacetate for use in water shut off operations. Gel swelling and the effects of salinity, injection time and flow rate on residual resistance factor (Frr) were investigated. In the presence of electrolytes, gel swelling decreased by about 80%. Results showed that oil permeability increased as inject...

In current theories of polyacrylamide gel electrophoresis, the idea prevails that molecular sieving relies on different accessibility of volume fractions and of cross-sectional area fractions (denoted "pores") to different-sized ions due to the effect of "geometric exclusion". This correlates with the assumption that all elements of a polyacrylamide network occupy fixed and unchangeable positio...

We have developed sparsely cross-linked "nanogels", subcolloidal polymer structures composed of covalently linked, linear polyacrylamide chains, as novel replaceable DNA sequencing matrixes for capillary and microchip electrophoresis. Nanogels were synthesized via inverse emulsion (water-in-oil) copolymerization of acrylamide and a low percentage (approximately 10(-4) mol %) of N,N-methylene bi...

Three types of investigations are described. (a) When a polymer chain carries reactive substituents, the reaction rate may be increased by very large factors if these groups are sufficiently close to each other. More distant groups interact at rates governed by the chain flexibility. A technique is described for studying the effect of the excluded volume on the probability of cyclic chain confo...

© Appl. Rheol. 15 (2005) 90-97 Abstract: There is often a need to perform rheological tests on dilute polymeric liquids at a time long after their initial preparation, for example if a more sensitive or novel method of measuring a material property (such as uniaxial/biaxial extensional viscosity or second normal-stress differences) becomes available. An inexpensive method of storing such fluids...