Gels multiple phases

Zimmerman, J.R. and Brittin, W.E. 1957. Nuclear magnetic resonance studies in multiple phase systems Lifetime of a water molecule in an absorbing phase on silica gel. J. Phys. Chem. 61, 1328-1333. 

Fig. 33. Equilibrium swelling degree of d/do of copolymer gels made of various molar ratios of acrylic acid and MAPTAC in water as a function of pH at 25 °C. Acrylic add ami MAPTAC ratios of the gels are indicated in the diagram. For some gels there appear multiple phases for the same value of pH. They are reached by varying pH through different paths...

Bismuth vanadate can be produced by either a wet process or high-temperature calcination. By the first method, an acidic solution of bismuth nitrate, Bi(N03)3. is mixed with an alkaline solution of sodium vanadate, Na3V04. The resultant gel is filtered, washed, and converted to crystalline form by low-temperature calcination at 200-500°C. Multiple-phase pigments can be created by coprecipitation of bismuth vanadate with molybdenum, tungsten, or niobium compounds. 

Multiple chromatographies are needed to purify benzophenones, and a variety of normal and reversed-phase solvent systems and solid phases including column chromatography over silica gel, reversed-phase, and Sephadex LH-20, as well as preparative TLC and HPLC have been employed. Isolation methods for selected benzophenones are given, and our experiences with the activity-guided isolation of xanthochymol (138) from G. xanthochymus fruits are discussed. 

Mafe S, Manzanares JA, English AE, Tanaka T (1997) Multiple phases in ionic copolymer gels. Phys Rev Lett 79 3086... 

Chiral stationary phases that are currently available can be classified into those containing cavities (cellulose derivatives, cyclodextrins, synthetic polymers, crown ethers, and chiral imprinted gels), affinity phases (bovine serum albumin, human serum albumin, a-glycoprotein, enzymes), multiple hydrogen-bond phases, Ti-donor and Ti-acceptor phases, and chiral ligand exchange phases. This classification scheme was used in a review that gave numerous pharmaceutical examples of separation by... 

Annaka, M. Tanaka, T. Multiple phase of polymer gels. Nature 1992, 335, 430-432. 

SrCoOs-g is a material with multiple phase structures. The influence of Sc doping in the B-site of SrCo03 5 on its lattice structure/phase stability, electrical conductivity, and cathode performance for IT-SOFCs was investigated [188]. SrSc cCoi c03 g x = 0.0-0.2) composite oxides were synthesized by a combined EDTA-citrate (EC) complexing sol-gel process. Sr(N03)2, Co(N03)2- H20, and SC2O3 were used as the raw materials for the metal ion sources. A maximum electrical conductivity and favorable cubic phase stability of the material were reached at the Sc " doping concentration of 5-10 mol%. 

The use of nanoparticles to treat disease is an area of huge research and industrial activity, none more so in the field of cancer treatment. Tumors are treated either by surgical removal or by radiotherapy or chemotherapy. Radiotherapy and chemotherapy target cells in their multiplication phase, meaning that rapidly reproducing cells such as tumor cells and hair follicles die more rapidly than other cells. However antitumor drugs lack specificity. Sol-gel materials can be modified to enable delivery of drugs to the required site. 

Zimmerman,. R., and W. E. Brittin (1957). Nuclear Magnetic Resonance Studies in Multiple Phase Systems Lifetime of a Water Molecule in an Adsorbing Phase on Silica Gel . The Journal of Physical Chemistry 61 (10) 1328-1333. 

Hydrated bilayers containing one or more lipid components are commonly employed as models for biological membranes. These model systems exhibit a multiplicity of structural phases that are not observed in biological membranes. In the state that is analogous to fluid biological membranes, the liquid crystal or La bilayer phase present above the main bilayer phase transition temperature, Ta, the lipid hydrocarbon chains are conforma-tionally disordered and fluid ( melted ), and the lipids diffuse in the plane of the bilayer. At temperatures well below Ta, hydrated bilayers exist in the gel, or Lp, state in which the mostly all-trans chains are collectively tilted and pack in a regular two-dimensional... 

Figure 7.13 Separation of a test eixture using automated multiple development with a universal mobile phase gradient from acetonitrile through dlchloromethane to carbon disulfide on a silica gel HPTLC plate. The chromatogram was scanned at different wavelengths to enhance the chromatographic information.

---