Correction: Equations of the state of hard sphere fluids based on recent accurate virial coefficients B5-B12.

Correction for 'Equations of the state of hard sphere fluids based on recent accurate virial coefficients B5-B12' by Jianxiang Tian et al., Phys. Chem. Chem. Phys., 2019, 21, 13070-13077. DOI.

Performance of the asymptotic expansion method to derive equations of state for hard polyhedron fluids.

The asymptotic expansion method is used to derive analytical expressions for the equations of state of 14 hard polyhedron fluids such as cube, octahedron, rhombic dodecahedron, etc., by knowing the values of only the first eight virial coefficients. The results for the compressibility factor were compared with the most recent ones reported in the literature and obtained by computer simulations. Good results (averaged deviations below 1%) are found for the 8 fluids studied. On the other hand, the method seems to be inadequate, at least with the presently available values for the virial coefficients and compressibility factors, for 4 polyhedron fluids. Unfortunately, sometimes the method does not give low deviations at high densities or it gives excessively high values for the location of the pole. As an advantage, the value of the pole for the compressibility factor is always positive, which is not observed when other methods are used.

Equations of the state of hard sphere fluids based on recent accurate virial coefficients B5-B12.

By using the recently published simulation data for the compressibility factor (M. N. Bannerman, L. Lue and L. V. Woodcock, J. Chem. Phys., 2010, 132, 084507; S. Pieprzyk, M. N. Bannerman, A. C. Branka, M. Chudak and D. Heyes, Phys. Chem. Chem. Phys., 2019, 21, 6886) and the recently published numerical virial coefficients B5-B12 (R. J. Wheatley, Phys. Rev. Lett., 2013, 110, 200601; C. Zhang and B. M. Pettitt, Mol. Phys., 2014, 112, 1427; A. J. Schultz and D. A. Kofke, Phys. Rev. E: Stat., Nonlinear, Soft Matter Phys., 2014, 90, 023301) of hard sphere fluids, we herein report the updated versions of the equations of the state of hard sphere fluids based on the asymptotic expansion method (J. Tian, H. Jiang, Y. Gui and A. Mulero, Phys. Chem. Chem. Phys., 2009, 11, 11213), the Padé approximants (N. Clisby and B. McCoy, J. Stat. Phys., 2006, 122, 15) and the exponential approximants (N. S. Barlow, A. J. Schultz, S. J. Weinstein and D. A. Kofke, J. Chem. Phys., 2012, 137, 204102) and compare them with other recently published equations. It is found that the so-called mKLM equation describes the relation of the compressibility factor versus the packing fraction with the highest accuracy. The asymptotic expansion method based equation Z(-5, 2) is recommended to well describe both the virial coefficients and the compressibility factor.

New equations of state for the hard polyhedron fluids.

In this paper, we derived a new equation of state for hard polyhedron fluids that is obtained by the knowledge of virial coefficients and a fit to the computer simulation data for the compressibility factor, and which contains two adjustable parameters. This equation reproduces exactly the correct known virial coefficients up to the ninth one and also the compressibility factor data with high accuracy, the absolute average deviations (AADs) being 0.05% for the stable state and 1.12% for both stable and metastable states for the hard tetrahedron fluid. For 12 of the other hard polyhedron fluids, it reproduces exactly the correct known virial coefficients up to the eighth one and also the compressibility factor data in the stable state with AADs less than 0.25%, with the only exception being the triangular prism polyhedron fluid.

Detection of cytomegalovirus in bronchoalveolar lavage fluid from immunocompromised patients with pneumonitis by viral culture and DNA quantification.

PURPOSE: To compare the detection of human cytomegalovirus (HCMV) in bronchoalveolar lavage (BAL) fluid by viral culture and quantitative polymerase chain reaction (qPCR), and to establish a viral load threshold that can identify cases of HCMV replication indicative of pneumonitis. There is currently no universal viral load cut-off to differentiate between patients with and without pneumonitis, and the interpretation of qPCR results is challenging. METHODS: 176 consecutive BAL samples from immunosuppressed hosts with signs and/or symptoms of respiratory infection were prospectively studied by viral culture and qPCR. RESULTS: Concordant results were obtained in 81.25% of the BAL samples. The rest were discordant, as only 34% of the qPCR-positive BAL samples were positive by culture. The median HCMV load was significantly higher in culture-positive than in culture-negative BAL samples (5038 vs 178 IU/mL). Using a cut-off value of 1258 IU/mL of HCMV in BAL, pneumonia was diagnosed with a sensitivity of 76%, a specificity of 100%, a VPP of 100% and VPN of 98%, and HCMV was isolated in 100% of the BAL cultures. CONCLUSION: We found that a qPCR-negative was a quick and reliable way of ruling out HCMV pneumonitis, but a positive result did not always indicate clinically significant replication in the lung. However, an HCMV load in BAL fluid of ≥ 1258 IU/mL was always associated with disease, whereas < 200 IU/mL rarely so.

Pressure-Surface Tension-Temperature Equation of State for n-Alkanes.

Herein, the geometric similitude concept is applied to propose a cubic equation that relates surface tension, saturation pressure, and temperature for n-alkanes. The input properties for each fluid are the molecular mass, pressure, temperature, and compressibility factor at the critical point. The model is applied to temperatures below 0.93·T c (critical point temperature). A total of 2429 surface tension values have been selected for 32 n-alkanes. The parameters of the model have been obtained with a fit of the surface tension values for 19 pure n-alkanes that are randomly chosen. Then, it is tested for the other 13 pure n-alkanes and used to predict the surface tension for 11 binary and 4 ternary mixtures. These predictions are compared with the reported experimental data. For pure n-alkanes, the overall absolute average deviation is 2.4%, including the correlation and testing sets. No additional adjustable coefficients are used for mixtures, yielding an overall absolute average deviation of 2.98% for the binary systems and 7.97% for the ternary ones. The results show that the model is accurate enough for predictions and that the highest deviations are due to the lack of agreement in the values of surface tension of pure fluids obtained from different sources.

New virial equation of state for hard-disk fluids.

Although many equations of state of hard-disk fluids have been proposed, none is capable of reproducing the currently calculated or estimated values of the first eighteen virial coefficients at the same time as giving very good accuracy when compared with computer simulation values for the compressibility factor over the whole fluid range. A new virial-based expression is here proposed which achieves these aims. For that, we use the fact that the currently accepted estimated values for the highest virial coefficients behave linearly with their order, and also that virial coefficients must have a limiting behaviour that permits the closest packing limit in the compressibility factor to be also adequately reproduced.

Asymptotic expansion based equation of state for hard-disk fluids offering accurate virial coefficients.

Despite the fact that more than 30 analytical expressions for the equation of state of hard-disk fluids have been proposed in the literature, none of them is capable of reproducing the currently accepted numeric or estimated values for the first eighteen virial coefficients. Using the asymptotic expansion method, extended to the first ten virial coefficients for hard-disk fluids, fifty-seven new expressions for the equation of state have been studied. Of these, a new equation of state is selected which reproduces accurately all the first eighteen virial coefficients. Comparisons for the compressibility factor with computer simulations show that this new equation is as accurate as other similar expressions with the same number of parameters. Finally, the location of the poles of the 57 new equations shows that there are some particular configurations which could give both the accurate virial coefficients and the correct closest packing fraction in the future when higher than the tenth virial coefficients are numerically calculated.

Equation of state for hard-sphere fluids offering accurate virial coefficients.

The asymptotic expansion method is extended by using currently available accurate values for the first ten virial coefficients for hard sphere fluids. It is then used to yield an equation of state for hard sphere fluids, which accurately represents the currently accepted values for the first sixteen virial coefficients and compressibility factor data in both the stable and the metastable regions of the phase diagram.

No effect of different bariatric surgery procedures on LINE-1 DNA methylation in diabetic and nondiabetic morbidly obese patients.

BACKGROUND: Bariatric surgery (BS) is proposed as a highly effective therapy for reducing weight and improving obesity-related co-morbidities. The molecular mechanisms involved in the metabolic improvement after BS are not completely resolved. Epigenetic modifications could have an important role. OBJECTIVE: The aim of this study was to evaluate the effect of different BS procedures (Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy) on global DNA methylation (long interspersed nucleotide element 1 [LINE-1]) in a group of nondiabetic and diabetic severely obese patients. SETTING: University hospital, Spain. METHODS: This study included 60 patients (30 nondiabetic and 30 diabetic severely obese patients) undergoing BS: 31 patients underwent Roux-en-Y gastric bypass and 29 underwent laparoscopic sleeve gastrectomy. Before and 6 months post-BS, anthropometric data, blood pressure, and metabolic parameters were determined. LINE-1 DNA methylation was quantified by pyrosequencing. We used the methylation levels of tumor necrosis factor-α as a control gene promoter. RESULTS: There were no differences between LINE-1 methylation levels at baseline and at 6 months after surgery (66.3±1.6 versus 66.2±2.06). Likewise, there was no statistically significant difference on LINE-1 methylation levels when we stratified according to metabolic status (diabetic versus nondiabetic), nor was there regarding the BS procedure. A strong correlation was shown between LINE-1 methylation levels and weight at baseline both in diabetic and nondiabetic obese patients (r = .486; P<.001). Tumor necrosis factor-α methylation levels increased significantly after BS in the group of diabetic obese patients. CONCLUSION: After BS, global LINE-1 methylation is not modified in the short term. More studies are required to determine if LINE-1 is a stable epigenetic marker, or, on the contrary, if it is susceptible to modification by external factors such as changes in lifestyle or a surgical intervention.

On the universal behavior of some thermodynamic properties along the whole liquid-vapor coexistence curve.

When thermodynamic properties of a pure substance are transformed to reduced form by using both critical- and triple-point values, the corresponding experimental data along the whole liquid-vapor coexistence curve can be correlated with a very simple analytical expression that interpolates between the behavior near the triple and the critical points. The leading terms of this expression contain only two parameters: the critical exponent and the slope at the triple point. For a given thermodynamic property, the critical exponent has a universal character but the slope at the triple point can vary significantly from one substance to another. However, for certain thermodynamic properties including the difference of coexisting densities, the enthalpy of vaporization, and the surface tension of the saturated liquid, one finds that the slope at the triple point also has a nearly universal value for a wide class of fluids. These thermodynamic properties thus show a corresponding apparently universal behavior along the whole coexistence curve.

Monolayer Adsorption of Ar and Kr on Graphite: Theoretical Isotherms and Spreading Pressures

The validity of analytical equations for two-dimensional fluids in the prediction of monolayer adsorption isotherms and spreading pressures of rare gases on graphite is analyzed. The statistical mechanical theory of Steele is used to relate the properties of the adsorbed and two-dimensional fluids. In such theory the model of graphite is a perfectly flat surface, which means that only the first order contribution of the fluid-solid interactions are taken into account. Two analytical equations for two-dimensional Lennard-Jones fluids are used: one proposed by Reddy-O'Shea, based in the fit on pressure and potential energy computer simulated results, and other proposed by Cuadros-Mulero, based in the fit of the Helmholtz free energy calculated from computer simulated results of the radial distribution function. The theoretical results are compared with experimental results of Constabaris et al. (J. Chem. Phys. 37, 915 (1962)) for Ar and of Putnam and Fort (J. Phys. Chem. 79, 459 (1975)) for Kr. Good agreement is found using both equations in both cases.

Are auditory warnings in the intensive care unit properly adjusted?

The purpose of this study was to determine whether auditory warnings in the intensive care unit (ICU) were properly adjusted. An intervention study (before- and-after assessment) was conducted in a 12-bed medical-surgical ICU of an acute-care teaching hospital in Barcelona, Spain. A total of 100 patients with stable haemodynamic and respiratory parameters were included. In the first 3-month phase of the study, minimum and maximum alarm parameters of breathing rate, expired volume/min, airway pressure, SaO(2), arterial blood pressure and heart rate were recorded. In the second 12-month phase of the study, the same alarm parameters were recorded every 4 hours in the patient's medical record. In the third 3-month phase of the study, alarm readings were recorded again as in the first phase. The change throughout coefficient of variation (CV) and the 95% confidence interval (CI) for each alarm were calculated. Following the intervention, there was a statistically significant improvement in alarm readings for expired volume, heart rate and systolic blood pressure, so that alarms had been more properly adjusted to the patient's real value. Nursing staff should be aware that auditory warnings in ICU stable patients are frequently set very far from suitable values. Recording of alarm parameters in the patient's medical record as a routine daily activity was an effective intervention for improving adjustment of auditory warnings.