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In recent work by Paschek [J. Chem. Phys. 120, 6674 (2004)] and others [see H. Docherty et al., J. Chem. Phys. 125, 074510 (2006) for a review] it has been suggested that, when coupled to a simple Lennard-Jones model for various small nonpolar solute molecules, the most common models of water (e.g., SPC/E and TIP4P) fail to reproduce quantitatively the solubility of small nonpolar solute molecules in water due in part to failing to account for polarization of the solute molecule. Given the importance of such systems as test-case prototype models of the solubility of proteins and biomolecules, in this work, we investigate the impact of using a polarizable solute model with the SPC/E, TIP3P, TIP4P, TIP4P-Ew, and TIP4P/2005 rigid water models. Specifically we consider Ne, Ar, Kr, Xe, and methane as solutes. In all cases we observe that the use of a polarizable solute improves agreement between experiment and simulations, with the best agreement seen for the largest solutes, Kr, CH(4), and Xe and the modern reparametrizations of the TIP4P model, i.e., the TIP4P-Ew and TIP4P/2005 models.

We compare a new classical water model, which features Gaussian charges and polarizability (GCPM) with ab initio Car-Parrinello molecular dynamics (CPMD) simulations. We compare the total dipole moment, the total dipole moment distribution, and degree of hydrogen bonding at ambient to supercritical conditions. We also compared the total dipole moment calculated from both the electron density (partitioning the electron density among molecules based on a zero electron flux condition), and from the center of localized Wannier function centers (WFCs). Compared to CPMD, we found that GCPM overpredicts the dipole moment derived by partitioning the electron density and underpredicts that obtained from the WFCs, but exhibits similar trends and distribution of values. We also found that GCPM predicted similar degrees of hydrogen bonding compared to CPMD and has a similar structure.

The Pirani scoring system, together with the Ponseti method of club foot management, was assessed for its predictive value. The data on 70 idiopathic club feet successfully treated by the Ponseti method and scored by Pirani's system between February 2002 and May 2004 were analysed. There was a significant positive correlation between the initial Pirani score and number of casts required to correct the deformity. A foot scoring 4 or more is likely to require at least four casts, and one scoring less than 4 will require three or fewer. A foot with a hindfoot score of 2.5 or 3 has a 72% chance of requiring a tenotomy. The Pirani scoring system is reliable, quick, and easy to use, and provides a good forecast about the likely treatment for an individual foot but a low score does not exclude the possibility that a tenotomy may be required.

Commonly obtained clear plasma or serum samples contain small amounts of hemoglobin derived from either naturally occurring processes or from collection trauma. Using the recently evaluated, highly specific, sensitive, quantitative procedure of first derivative spectroscopy, the hemoglobin concentration in nine types of vacuum collection containers was measured, including three types of anticoagulant, three tube sizes, and tubes with or without serum separators. Using this procedure, reference values were established for plasma and serum hemoglobin. These values are the result of the combined effect of red cell trauma during the collection, interaction with the anticoagulant or the serum separator material, and physiologic changes. The observed hemoglobin levels were best described by a log normal distribution pattern. The three plasma collection samples showed lower average values than the serum samples. The citrate anticoagulant gave the lowest plasma hemoglobin average value of 32.7 mg per L (3.27 mg per dl) 9.2 to 123 mg per L (0.92 to 12.3 mg per L 2SD range). It is concluded that the average hemoglobin concentration owing to the collection procedure is less than 100 mg per L (10 mg per dl). A serum or plasma hemoglobin concentration over 200 mg per L (20 mg per dl) is probably due to abnormal physiologic causes and not collection artefact. Serum or plasma hemoglobin measurements evaluated by these criteria can be relied upon as an accurate approximation of excess hemoglobin produced by a pathologic hemolytic process such as acute autoimmune hemolytic anemia, major blood group incompatibility or paroxysmal hemoglobinuria.

The authors tested the plasma hemoglobin measurement procedure of Soloni, Cunningham, and Amazon (Am J Clin Pathol 1986;85:342-347), which uses recording derivative spectrophotometry. By this technique, the authors were able to measure plasma or serum hemoglobin down to a level of 10 mg/L (1 mg/dL). The method was found to be quantitative and not affected by bilirubin or lipemia. Methemoglobin did not interfere with the assay. The observed first derivative maxima and minima were reproducible but instrument dependent. The authors applied this technique to the measurement of serum hemoglobin in 100 healthy human subjects. They observed a geometric mean value of 68 mg/L (6.8 mg/dL) with the actual range 21-189 mg/L (2.1-18.9 mg/dL). The authors confirm that this technique is a simple, rapid, and reproducible method for determining plasma or serum hemoglobin.