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Factors Affecting The Association Of Single- And Double-Stranded Rnas With Montmorillonite Nanoclays, A. Gujjari, B. V. Rodriguez, J. Pescador, Corina Maeder, G. W. Beall, L. K. Lewis
Factors Affecting The Association Of Single- And Double-Stranded Rnas With Montmorillonite Nanoclays, A. Gujjari, B. V. Rodriguez, J. Pescador, Corina Maeder, G. W. Beall, L. K. Lewis
Corina Maeder
Montmorillonite (MMT) nanoclays exist as single and stacked sheet-like structures with large surface areas that can form stable associations with many naturally occurring biomolecules, including nucleic acids. They have been utilized successfully as vehicles for delivery of both drugs and genes into cells. Most previous studies have focused on interactions of MMT with DNA. In the current study, we have investigated the binding of small RNAs similar to those used for RNA interference (RNAi) therapy to two major forms of the clay, Na-MMT and Ca-MMT. Association of both forms of MMT with several double-stranded RNAs (dsRNAs), including 25mers, 54mers and …
Strength Of Bentonite Water-Well Annulus Seals In Confined Aquifers, Fred Ogden
Strength Of Bentonite Water-Well Annulus Seals In Confined Aquifers, Fred Ogden
Fred L. Ogden
The advantages of bentonite clay for sealing applications are well known. Bentonites have extremely low permeability, do not affect formation water chemistry, and have the ability to swell and deform in response to subsurface changes. The major limitation on the applicability of bentonite for water well annulus sealing is strength. Strength tests conducted in a physical model of a water well identified the expected magnitude of shear strength for several commercially available bentonite well-sealing products. The dependence of bentonite strength in the annulus of a water well on both setting time and borehole geometry is discussed. Force balance calculations for …
Setting Time Effects On Bentonite Water-Well Annulus Seals, Fred L. Ogden
Setting Time Effects On Bentonite Water-Well Annulus Seals, Fred L. Ogden
Fred L. Ogden
Shear strength tests are conducted in a model of a water well on four, commercially available, granular bentonite well sealing products. The time dependency of annulus seal shear strength and resistance to piping is examined. Dry bentonite samples are placed through water in the annular space between the casing and borehole and allowed to set for a specified time. Pressure is applied at a constant rate to one end of the clay seal until shear or piping failure occurs. Pressure and seal displacement data are recorded on a digital data acquisition system. Annulus seal strength and resistance to piping increase …