Non-empirical Treatment Research Articles

Empirical treatment of asymptomatic contacts of gonorrhoea: patient views.

We conducted an anonymous cross-sectional survey of patients attending sexual health centres in New South Wales, Australia, on the acceptability of empirical and non-empirical treatment models and patients' concerns about antimicrobial resistance. Most of the 823 survey participants were willing to wait for treatment until their results were reported; 77% and 53% would agree to wait for treatment if results were available in 2 and 7 days respectively. Participants were less likely to agree to non-empirical treatment if they lived in regional and remote areas compared with those in a major city (odds ratio (OR) 0.5; 95% confidence interval (CI) 0.35-0.73). Most participants (70%) were worried about infections becoming resistant to antibiotics, with heterosexual men and women being less likely than gay and bisexual men to be worried (heterosexual men: OR 0.64, 95% CI 0.44-0.94; women: OR 0.64 95%, CI 0.44-0.92). Non-empirical treatment was acceptable to most participants, but patient preference, ability to return for treatment and timeliness of results are factors that should inform individual treatment decisions.

A DFT-based theoretical model for the calculation of spectral profiles of lanthanide M4,5-edge x-ray absorption.

This presentation reports the theoretical study of 3d core-electron excitation in lanthanide compounds in terms of electronic structure effects and optical properties. The calculations are done at the Density-Functional Theory (DFT) level complemented with an effective Hamiltonian based on ligand-field theory. The strategy consists of obtaining from DFT a totally symmetric density, where an active subspace is set up that forms the basis of the fivefold 3d and sevenfold 4f atomic orbitals of the lanthanide ion. This active subspace is defined with the fractional occupation of electrons, which represents open-shell species with the composite configuration 3d94fn+1. Based on the ligand-field analysis of the DFT results, the multiplet energies and ligand-field effects associated with the configuration 3d94fn+1 are evaluated; and the X-ray absorption spectra are simulated in terms of the intra-atomic 4fn → 3d94fn+1 electron transitions within the electric-dipole approximation. Examples for application are proposed taking into consideration the isolated trivalent lanthanides ions and compounds Cs2NaPrX6, with X = F, Cl, and Br. The results are compared with available experimental data, where a good agreement is qualitatively achieved. Also, the screening of the inter-electron repulsion and spin-orbit coupling interaction is numerically obtained that allows one to establish a fully non-empirical treatment of the 3d core-electron excitation, which can be valuable in the characterization and modeling of the spectral profiles of lanthanide M4,5-edge X-ray absorption spectroscopy. The enclosed theoretical model, which is being implemented in the Amsterdam Density Functional (ADF) suite of programs, is computationally economic and can be applied to any lanthanide system without limitations in terms of the size of the matrix elements of the effective Hamiltonian or the coordination symmetry of the lanthanide center.

The Use of Guidelines for the Empiric Treatment of Hospital-Acquired Pneumonia

Several practice guidelines for the empirical antimicrobial treatment of hospital-acquired pneumonia (HAP) have been developed, but the acceptance and use of such guidelines are unknown. To assess physicians' use of empirical HAP guidelines published by the American Thoracic Society (ATS) and by The University Health Network, Toronto, Ontario. A retrospective assembly and chart review. A university teaching hospital. One hundred fifteen consecutive patients who had been diagnosed with pneumonia more than 48 h after admission to hospital over a 10-month period. The charts of 115 patients were reviewed. Seventy-five patients (65%) were treated empirically. Forty patients (35%) were treated based on microbiological data that were available before the initiation of antibiotics. Patients who received nonempirical treatment for HAP had a significantly greater acuity of illness than the empirically treated group. Thirty-seven patients (49%) who received empirical therapy were treated according to either ATS or hospital guidelines for HAP. The use of guideline-concordant antimicrobial therapy had no measurable effect on in-hospital mortality (eight of 37 patients [21.6%] versus seven of 38 patients [18.4%], P=0.96) or median length of stay (19 days versus 21 days, P=0.30). Patients whose treatment did not follow guideline recommendations tended to receive appropriate antimicrobial coverage more often than did those patients whose treatment was guideline concordant (15 of 18 patients [83%] versus six of 11 patients [55%], P=0.49). Institutional and ATS guidelines for the empirical treatment of HAP are less widely used than would be predicted by chance at The University Health Network. The clinical utility of these guidelines remains to be proven.

Double perturbation calculation of the Jgem nuclear spin-spin coupling constant of methane

A nonempirical treatment of the nuclear spin-spin coupling constant J gem of methane using a molecular orbital perturbation method is presented. Starting with the best LCAO-SCF MO's corresponding to a minimal basis set of Slater-type AO's, the value calculated for J gem by the usual second-order perturbation treatment is found to be exceedingly small (−1.27 cps). Agreement with experiment is recovered (−15.02 cps; exptl. −12.4 cps) if the third-order contributions coming from correlation effects are included by a double perturbation treatment with respect to the configuration interaction and the contact term. The same calculations have been repeated with equivalent quasilocalized orbitals, in order to analyze the various contributions in terms of bond excitations. A possible extension of these results to the problem of coupling constants between more distant nuclei is considered by means of a diagrammatic method.

A two-electron model for the Li2 molecule

The inclusion of complete orthogonalization to the inner shell in the simple non-empirical treatment of Ref. [1] has been studied with special reference to energies. The comparison with experimental data for Li2 is also discussed.