Time to Clinical Stability in Children With Community-Acquired Pneumonia

BACKGROUND AND OBJECTIVES

Time to clinical stability (TCS) is a commonly used outcome in adults with community-acquired pneumonia (CAP), yet few studies have evaluated TCS in children. Our objective was to determine the association between TCS and disease severity in children with suspected CAP, as well as factors associated with reaching early stability.

METHODS

This is a prospective cohort study of children (aged 3 months to 18 years) hospitalized with suspected CAP. TCS parameters included temperature, heart rate, respiratory rate, and hypoxemia with the use of supplemental oxygen. TCS was defined as time from admission to parameter normalization. The association of TCS with severity and clinical factors associated with earlier TCS were evaluated.

RESULTS

Of 571 children, 187 (32.7%) had at least 1 abnormal parameter at discharge, and none had ≥3 abnormal discharge parameters. A greater proportion of infants (90 [93%]) had all 4 parameters stable at discharge compared with 12- to 18-year-old youths (21 [49%]). The median TCS for each parameter was <24 hours. Younger age, absence of vomiting, diffusely decreased breath sounds, and normal capillary refill were associated with earlier TCS. Children who did not reach stability were not more likely to revisit after discharge.

CONCLUSIONS

A TCS outcome consisting of physiologic variables may be useful for objectively assessing disease recovery and clinical readiness for discharge among children hospitalized with CAP. TCS may decrease length of stay if implemented to guide discharge decisions. Clinicians can consider factors associated with earlier TCS for management decisions.

Graphitization of Glassy Carbon after Compression at Room Temperature

Glassy carbon is a technologically important material with isotropic properties that is nongraphitizing up to ∼3000 °C and displays complete or "superelastic" recovery from large compression. The pressure limit of these properties is not yet known. Here we use experiments and modeling to show permanent densification, and preferred orientation occurs in glassy carbon loaded to 45 GPa and above, where 45 GPa represents the limit to the superelastic and nongraphitizing properties of the material. The changes are explained by a transformation from its sp^{2} rich starting structure to a sp^{3} rich phase that reverts to fully sp^{2} bonded oriented graphite during pressure release.

Bright and photostable nitrogen-vacancy fluorescence from unprocessed detonation nanodiamond

Bright and photostable fluorescence from nitrogen-vacancy (NV) centers is demonstrated in unprocessed detonation nanodiamond particle aggregates. The optical properties of these particles is analyzed using confocal fluorescence microscopy and spectroscopy, time resolved fluorescence decay measurements, and optically detected magnetic resonance experiments. Two particle populations with distinct optical properties are identified and compared to high-pressure high-temperature (HPHT) fluorescent nanodiamonds. We find that the brightness of one detonation nanodiamond particle population is on the same order as that of highly processed fluorescent 100 nm HPHT nanodiamonds. Our results may open the path to a simple and up-scalable route for the production of fluorescent NV nanodiamonds for use in bioimaging applications.

Nanostructured SnO(2) films prepared from evaporated Sn and their application as gas sensors

This paper describes the morphology, stoichiometry, microstructure and gas sensing properties of nanoclustered SnO(x) thin films prepared by Sn evaporation followed by a rheotaxial growth and thermal oxidation process. Electron microscopy was used to investigate, in detail, the evolution of the films as the oxidation temperature was increased. The results showed that the contact angle, perpendicular height, volume and microstructure of the clusters all changed significantly as a result of the thermal oxidation processes. Electron diffraction and x-ray photoelectron spectroscopy measurements revealed that after oxidation at a temperature of 600 °C, the Sn clusters were fully transformed into porous three-dimensional polycrystalline SnO(2) clusters. On the basis of these results, a prototype SnO(2) sensor was fabricated and sensing measurements were performed with H(2) and NO(2) gases. At operating temperatures of 150-200 °C the film produced measurable responses to concentrations of H(2) as low as 600 ppm and NO(2) as low as 500 ppb.

Co-trimoxazole versus nafcillin in the therapy of experimental meningitis due to Staphylococcus aureus

Co-trimoxazole was compared with nafcillin against Staphylococcus aureus in vitro and in the therapy of experimental Staph. aureus meningitis in rabbits. Co-trimoxazole (trimethoprim:sulphamethoxazole in a 1:20 ratio) was synergistic against 22/24 strains of Staph. aureus in vitro. The MBC90 of co-trimoxazole and nafcillin were 0.156-3.12 mg/l and 0.25 mg/l, respectively, concentrations below those achievable in purulent cerebrospinal fluid. The rate of bacterial killing (Staph. aureus) by co-trimoxazole and nafcillin were similar in both broth and pooled CSF in vitro. However, the MBC increased and the rate of bactericidal activity of both agents declined when tested in CSF at a higher inoculum (10(7) cfu/ml). During continuous intravenous infusion therapy of a reproducible, uniformly fatal (if untreated) model of experimental Staph. aureus meningitis, serum concentrations of all agents closely approximated those found in humans receiving standard parenteral regimens. The mean percent penetration into CSF ([CSF]/[serum] X 100) was 2.9, 35.6 and 27.1% for nafcillin, trimethoprim and sulphamethoxazole, respectively. Although both nafcillin and co-trimoxazole therapy reduced CSF Staph. aureus concentrations significantly more rapidly (P less than 0.001) when compared to untreated controls, the bactericidal rate was modest. The CSF was rendered sterile in 0/64 animals treated with either regimen for 8 h. Nafcillin was more rapidly bactericidal in vivo (P less than 0.03) than co-trimoxazole in this model. Caution is advised in the use of co-trimoxazole for infections of the central nervous system caused by Staph. aureus.