Fluid 2.0 (1905)
Kenefick RW, Maresh CM, Armstrong LE, Riebe D, Echegaray ME, Castellani JW. Rehydration with fluid of varying tonicities: effects on fluid regulatory hormones and exercise performance in the heat. J Appl Physiol 2007; 102: 1899-1905.
Fluid 2.0 (1905)
4-5%exercise-induced hyhpohydration caused subjects to become hyperosmotic, hypovolemic, and elevated circulaing AVP, ALD. Following partial rehydration, there were no overall differences in %change in Pvol or Pna, Pos, AVP, ALD among treatments. No greater fluid restoration with 0.9% compared with 0.45% IV, nor was there greater fluid restoration associated with IV versus oral treatment. No cardiovascular, thermoregulatory or performance advantages during subsequent exercise in the heat associated with either a particular solution or administration route.
If color Doppler imaging demonstrates blood flow within the contents of a complex cyst or dilated duct, then these contents consist of solid tissue rather then just debris, blood clot, or echogenic fluid. However, we have seen solid tumors that lack demonstrable blood flow on color Doppler imaging. Several investigators reviewed the ability of color Doppler US or contrast-enhanced Doppler US to distinguish benign from malignant lesions. The results were variable; Doppler US is not generally used to distinguish benign from malignant solid breast masses.
If it is uncertain whether a nodule seen on US is a complex cyst or solid mass, US-guided aspiration of the cyst is often performed. This procedure is also performed if the appearance of a complex cyst on US is of concern. The aspirate may be sent for cytologic evaluation, though there is no general consensus about the indications for cytology. Some clinicians send only the fluid for analysis if it is bloody.
Experimental data on the structure and properties of melts and fluids relevant to water-melt interaction in hydrous magmatic systems in the Earth's interior have been reviewed. Complex relationships between water solubility in melts and their bulk composition [Al/Si-ratio, metal oxide/(Al + Si) and electron properties of metal cations] explain why water solubility in felsic magmas such as those of rhyolite and andesite composition is significantly greater than the water solubility in basalt melts. The silicate solubility in aqueous fluid is also significantly dependent on composition with metal oxide/(Al + Si) and electron properties of the metal cations, the dominant variables. Hydrogen bonding is not important in hydrous fluids and melts at temperatures above 500C to 550C and does not, therefore, play a role in hydrous magmatic systems. The properties of hydrous melts and aqueous solutions are governed by how the silicate speciation (Qn species, where n is the number of bridging oxygen in an individual species) varies with bulk composition, silicate composition, temperature, and pressure. The reactions that describe the interactions are similar in melts, fluids, and supercritical fluids. The degree of melt polymerization caused by dissolved water varies with melt composition and total water content. Silicate- and alkali-rich felsic magmatic melts are more sensitive to water content than more mafic magmas. Transport and configurational properties of hydrous magmatic melts can be modeled with the aid of the Qn speciation variations. Liquidus and melting phase relations of hydrous systems also can be described in such terms, as can minor and trace element partition coefficients. Stable isotope fractionation (e.g., D/H) can also be rationalized in this manner. Critical to these latter observations is the high silicate concentration in aqueous fluids. These components can enhance solubility of minor and trace elements by orders of magnitude and change the speciation of H and D complexes so that their fractionation factors change quite significantly. Data from pure silicate-H2O systems cannot be employed for these purposes.
Aqueous solutions in the Earth's interior are efficient solvents of oxide components (Zhang and Frantz 2000; Manning 2004). Several mol% of silicate components dissolve under conditions corresponding to those of the deep continental crust and upper mantle. In the upper mantle, there can be complete miscibility between H2O and silicate (Bureau and Keppler 1999; Mibe et al. 2007). Major element solutes in aqueous fluids (silicate components) can also enhance the solubility of other components by up to orders of magnitude (Pascal and Anderson 1989; Antignano and Manning 2008; Mysen 2012a, b; Ayers and Watson 1993). Transport, volume, and mixing properties of silicate-rich aqueous fluids differ in important ways from those of pure H2O (Audetat and Keppler 2004; Hunt and Manning 2012; Hack and Thompson 2012; Foustoukos and Mysen 2013).
The property behavior of melts and fluids in hydrous silicate systems at the high temperatures and pressures can be traced to the relationships between fluid and melt structure and their properties. Most experimental and theoretical studies have focused on the behavior in chemically simpler systems in order to isolate the effects of individual intensive and extensive variables. With the information from chemically simpler systems, we can model melt and fluid behavior in systems relevant to natural processes. In this review, these relationships will be presented and their applications to natural systems will be discussed.
In the schematic phase diagram in Figure 4, the boundaries silicate melt + aqueous fluid/aqueous fluid and silicate crystals + aqueous fluid/aqueous fluid define the silicate solubility in the fluid above and below the solidus of the system. The solubility of SiO2 in H2O has been the subject of more extensive experimental study than other chemically more complex silicates. From a compilation of available high-pressure/high-temperature solubility data, an effective way to describe solubility is in terms of temperature and the density of pure H2O at the temperature (and pressure) of interest (Manning 1994; see also Figure 7). It must be emphasized, however, that the empirical relationship used for this purpose,
Silica solubility in fluid in equilibrium with quartz. As a function of the density of pure H2O at 1 GPa and temperatures indicated calculated with the algorithm of Manning (1994) (Equation 1).
Solubility of silica (SiO 2 ) in fluid. Coexisting with enstatite + forsterite (0.49 to 1.7 GPa pressure, closed symbols) and with enstatite (3.6 GPa pressure, closed symbols) in MgO-SiO2-H2O fluid calculated with the algorithm of Newton and Manning (2002) (results from Mysen et al. 2013).
Solubility of Al 2 O 3 in aqueous fluid in the system Na 2 O-Al 2 O 3 -SiO 2 -H 2 O-NaCl. As a function of silica solubility and NaCl mol fraction in fluid. Symbols indicate the coexisting solid phases. Data from Newton and Manning (2008).
Oxides that are essentially insoluble in pure H2O also can be affected quite strongly by other solutes such as silicate and aluminosilicate components. As an example, the solubility if Ti4+ in fluid in equilibrium with melt in the Na2O-Al2O3-SiO2-TiO2-H2O is a strong positive function of concentration of aluminosilicate component in addition to temperature and pressure (Antignano and Manning 2008; Mysen 2012a; see Figure 10). This is a very different solution behavior than that of TiO2 in the simple system, TiO2-H2O; here, the Ti solubility is in the parts per million range (Audetat and Keppler 2005; Antignano and Manning 2008). Similar effects have been observed for P5+ and other high field strength cations (Mysen 2011; Bernini et al. 2013). It follows, therefore, that during dehydration of subducting slabs where the fluid is quite silicate rich, it will likely carry significantly greater proportions of nominally refractory oxides than that expected from solubility measurements with pure H2O as the solute (see also Manning 2004).
TiO 2 solubility in fluids in equilibrium. With rutile in the system TiO2-Al-silicate (NaAlSi3O8 starting composition) as a function of SiO2 in solution. Data from Antignano and Manning (2008).
The behavior of an aqueous fluid in equilibrium with molten or crystalline silicates at high temperature and pressure may not be addressed by examination of quenched materials because most, perhaps all, of their properties (including the structure itself) cannot be determined by examination of the high-temperature/high-pressure fluid after quenching to ambient conditions. Fluid structure studies require, therefore, examination while the sample is at the temperature and pressure of interest. However, before addressing such experimental environments, structural data from quenched melts will be discussed.
Experimental protocols have recently been implemented for examination of fluids and melts in hydrous silicate systems at deep crustal and mantle pressures and temperatures in situ while the sample is at the desired pressure and temperature conditions. Structural data obtained under such conditions are, therefore, increasingly available from all regions of silicate-H2O phase diagrams (Figure 4). In considering such data, commonly obtained in so-called hydrothermal diamond anvil cells (e.g., Bassett et al. 1994), the experiments usually are conducted in such a manner that pressure is a variable dependent on temperature. This means that increasing temperature normally is associated with increasing pressure. In the following discussion, this is the case unless otherwise indicated.
Evolution of ratio of hydrogen bonded to isolated OH bonds. In hydrous Na-aluminosilicate melts and in silicate-saturated aqueous fluids as a function of temperature (and pressure) (data from Mysen 2012a, b.)
In hydrous silicate systems, the ratio of mol fraction of water species, X OH / X H 2 O 0 , in fluid, melt, and supercritical fluid varies with temperature (Mysen 2010b; see also Figure 18). The X OH / X H 2 O 0 ratio of water in fluid and melt converges at the second c.p. (Figure 18). The existence of OH groups in all three phases (melt, fluid, supercritical fluid) implies structural interaction between water and silicate components. In fact, structural data obtained from vibrational spectroscopy indicate that in any silicate systems, the types of Qn species in fluids, melts, and supercritical fluids resemble one another (Mysen 2009) although their concentration at any temperature and pressure depends on the silicate composition and whether in fluids or melts. The latter differences are evident in the NBO/T of the silicate melt being considerably lower (the melt is more polymerized) than coexisting fluid (Figure 19). The NBO/T values approach each other with increasing temperature and pressure until they merge at c.p. Interestingly, at higher temperature and pressure above those that define the c.p., the silicate in supercritical aqueous fluids becomes further depolymerized (NBO/T increases) (see Figure 19). 041b061a72