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This review covers studies in which simulated body fluid (SBF) has been used either to evaluate in vitro the bone bonding ability of a material or to produce a biomimetic coat on a material surface. The review focuses on materials with grafted functional polymer chains and functional polymer substrates. It is restricted to the phosphate, phosphonate, carboxylate and sulfonate functional groups as these mimic the anionic groups which are found on biological molecules implicated in mammalian bone mineralization. In this regard, the review covers articles from 1990 to mid-2015.Simulated body fluid; Graft copolymers; Polymers with anionic groups; In vitro mineralization

In biological systems, hydroxyapatite (HAP) mineralization is directed by macromolecules with anionic functional domains. This study investigates the effect of four anionic polymers with varying functional groups with respect to their inhibition of HAP growth. The anionic polymers include naturally occurring alginate and heparin as well as synthesized phosphorylated alginate and poly(3-sulfopropyl acrylate) (PSPA), thus investigating the three anionic functional groups of carboxylate, phosphate, and sulfate. Crystal growth inhibition was studied through the determination of the rates of HAP crystal growth while maintaining a constant composition of the supernatant as well as by investigations of the morphology of crystals grown in the presence of the anionic polymers. It was found that neither alginate nor PSPA had a large effect on crystal growth, phosphorylated alginate showed strong nonspecific binding, and heparin displayed preferential binding to the 002 face of the crystal.

Phosphorylation of alginate was achieved using a heterogeneous urea/phosphate reaction. The degree and stereoselectivity of phosphorylation as well as the effects on the physical properties of the polysaccharide were investigated by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopies, inductively coupled plasma optical-emission spectroscopy (ICP-OES), and size exclusion chromatography (SEC). Multidimensional NMR studies of the phosporylated alginate revealed that phosphorylation of the M residues occurred predominantly at the C3 (equatorial) carbon of the polysaccharide ring. In addition, a more comprehensive assignment of the (1)H NMR spectrum of alginate, compared with those previously reported in the literature, is provided here. Hydrogel materials were formed from ionically cross-linked blends of phosphorylated alginate and alginate. These blended hydrogels showed an enhanced resistance to degradation by chelating agents compared with cross-linked alginate hydrogels and a reduction in their mineralization potential.

We report a case of squamous cell carcinoma of the breast in a patient with previous adenocarcinoma in the unilateral breast. Squamous cell carcinoma is often cystic in nature with a variable presentation on mammogram. Its diagnosis necessitates the preclusion of a primary site of squamous carcinoma elsewhere in the body. The treatment of this cancer is similar to other types of breast carcinoma. Its prognosis remains unclear.

The pressure drop due to flow within a propped fracture results from three mechanisms: viscous drag of the fluid, inertial effects associated with the movement of fluid around the proppant grains, and multiphase effects associated with the interaction of the different fluid phases. Most existing fracture models and production simulators analyze the effects of viscous drag only, often underestimating the total pressure drop in the fracture by one or two orders of magnitude. These models rely solely on the reference permeability of the proppant, which is measured in the laboratory with extremely low flow rates of 2 to 10 cc/min. This paper reviews the design changes necessary to accommodate the incremental pressure losses resulting from multiphase and non-Darcy flow, and shows application of the theory to two operators' stimulation programs. Production rate projections and economic analyses are provided for fracture treatments conducted in two field programs (both gas reservoirs): Total-Fina-Elf's development in the Frio and Vicksburg reservoirs of South Texas and Chevron USA's Birch Creek Unit in the Green River Basin of Wyoming. Fracture treatments in existing wells had been designed with traditional Darcy flow models. New stimulation treatments were redesigned to include multiphase and non-Darcy flow effects. This paper provides details of the two different stimulation treatment designs in each of the development programs and the production results – average productivity increases of 20 to 30% for the new wells compared to offset wells treated with stimulations based on Darcy flow design models.

Pineal N-acetyltransferase (NAT) activity in 10-day-old rat pups was used to examine several aspects of the developing circadian timing system. When born and reared under constant darkness, 10-day-old animals manifested a clear daily rhythm of NAT activity whose phase was in time with the estimated circadian time of the mother (set by the lighting cycle during pregnancy). When pups were reared in constant darkness from birth by a foster mother whose circadian time was 180 degrees (12 h) out of phase with that of the natural mother, the resulting population profiles of NAT activity were arrhythmic. Analysis of the individual litter profiles from this experiment showed a variable postnatal influence of the maternal circadian system on the timing of the developing circadian system. Neither cross-fostering per se nor social interactions among litter mates contributed significantly to the apparent maternal influence. The magnitude of the postnatal maternal influence was not the same throughout development, but was most apparent during the first 5 days of life. Neonatal blinding (within 24 h of birth) did not appreciably alter the maternal influence. Extraretinal photoreception does not contribute to entrainment of the circadian clock during postnatal development, and retina-mediated photic entrainment is present by 10 days of age. The results indicate that pineal NAT activity monitored in 10-day-old rats provides a useful paradigm for studying the developing circadian system.

Cerebrospinal fluid (CSF) was serially withdrawn in individual, unanesthetized, unrestrained rats and assayed for vasopressin using a sensitive and specific radioimmunoassay. A prominent daily rhythm in the CSF concentrations of this peptide was found under diurnal lighting conditions. Low levels during the dark period alternated with high values during the light period; the rhythm appeared to anticipate the artificial 'dawn' and 'dusk' by a few hours. An 8-h phase shift in diurnal lighting caused a corresponding phase shift in the CSF rhythm. In addition, the rhythm persisted for at least 10 days in the absence of periodic environmental lighting cues in animals blinded by bilateral orbital enucleation; the rhythm was disrupted after 10 days of constant light. Blood vasopressin concentrations did not show a daily rhythm. Our results indicate that the daily vasopressin rhythm in rodent CSF is endogenously generated and that its phase is synchronized to the environmental light-dark cycle.