Antimicrobial therapy for otitis media with effusion ( secretory otitis media)

Objective. —To determine the effectiveness of antimicrobial treatment for otitis media with effusion ( secretory otitis media) in children. Data Source. —We report the reexamination of a previously published study by Mandel et al that evaluated the efficacy of a 2-week course of antimicrobials (amoxicillin trihydrate) with and without a 4-week course of an oral decongestant-antihistamine combination in a double-blind, placebo-controlled, randomized trial involving 518 infants and children with otitis media with effusion. Data Synthesis. —At 4 weeks, amoxicillin efficacy as determined by a tympanometric criterion (P=.121) or by a measure of improvement in hearing (P=.311) was insignificant. Only by otoscopic judgment, which is shown to contain a systematic bias as used in this clinical trial, could an argument be made for a marginal efficacy of amoxicillin at the 4-week end point. Logistic regression analyses of the combined effects of treatment and prognostic factors showed no significant differences between placebo- and antibiotic-treated groups for unilateral effusions and for bilateral effusions. When subjects with unilateral and bilateral effusions were combined, the estimated efficacy of antibiotic treatment was 12.3% by otoscopy (P =.014) and 4.8% by tympanometry (P =.171). We also demonstrate the sensitivity of outcome to diagnostic measures used and provide statistical evidence questioning the validity of otoscopic observations in this study. Six weeks after the termination of amoxicillin therapy, the recurrence of effusion was two to six times higher in the amoxicillin-treated children than in those treated with placebo (P=.001), and resolution of effusion was not significantly different among antibiotic and placebo groups (13.6% and 11.3%, respectively; P=.477). Conclusions. —Amoxicillin with and without decongestant-antihistamine combination is not effective for the treatment of persistent asymptomatic middle-ear effusions in infants and children

Entry corridor definition and SM/RCS deorbit requirements for Apollo block 1 earth orbit missions. Project Apollo

Entry corridor definition and SM reaction control system for Apollo Block 1 earth orbit mission

Ultraviolet Curing of Highly Loaded Ceramic Suspensions for Stereolithography of Ceramics

Ceramic green bodies can be created using stereolithography methods where a ceramic slip consisting of 45-55 vlo ceramic powder is dispersed within an ultraviolet-curable aqueous acrylamide solution. Two ceramic materials were investigated: silica [Si02] for investment casting purposes, and alumina [AI203] for structural parts. After mixing the powders in the curable solution, the ceramic slip is tape cast onto a substrate for cure under a high intensity ultraviolet lamp (220-450 nm) at different exposure times. The materials systems were evaluated at different solids loadings (10-50 v/o) for cure thickness and viscosity control. Silica had a cure depth of 330 f.lm at a solids loading of 55 vlo, and at 50 vlo, alumina had a cure depth of 300 f.lm. Preliminary work utilizing scattering theory revealed the cure depth is controlled by the particle size and the refractive index difference between the ceramic and ultraviolet solution. The refractive index difference is the dominating factor. Two particle size distributions of alumina were used to more accurately determine the effect of particle size.Mechanical Engineerin

Scattering of ultraviolet radiation in turbid suspensions

A Beer’s law expression for the penetration depth of ultraviolet radiation in a concentrated suspension of scattering particles is used to model the depth of cure for a suspension of ceramic particles in a medium of photocurable monomers. The cure depth is predominantly controlled by the square of the refractive index difference between the ceramic particles and the medium, Δn2 = (np−n0)2Δn2=(np−n0)2. A secondary effect on the cure depth is the ratio of the interparticle spacing to the ultraviolet wavelength. Theoretical results agree with experimental data for 0.40–0.50 volume fraction ceramic-filled suspensions. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71270/2/JAPIAU-81-6-2538-1.pd

7. Recent Excavations on Prehistoric and Dynastic Sites in Egypt.

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Fly-by-light flight control system technology development plan

The results of a four-month, phased effort to develop a Fly-by-Light Technology Development Plan are documented. The technical shortfalls for each phase were identified and a development plan to bridge the technical gap was developed. The production configuration was defined for a 757-type airplane, but it is suggested that the demonstration flight be conducted on the NASA Transport Systems Research Vehicle. The modifications required and verification and validation issues are delineated in this report. A detailed schedule for the phased introduction of fly-by-light system components has been generated. It is concluded that a fiber-optics program would contribute significantly toward developing the required state of readiness that will make a fly-by-light control system not only cost effective but reliable without mitigating the weight and high-energy radio frequency related benefits

Effect of prolonged space flight on cardiac function and dimensions

Echocardiographic studies were performed preflight 5 days before launch and on recovery day and 1, 2, 4, 11, 31 and 68 days postflight. From these echocardiograms measurements were made. From these primary measurements, left ventricular end-diastolic volume, end-systolic volume, stroke volume, and mass were derived using the accepted assumptions. Findings in the Scientist Pilot and Pilot resemble those seen in trained distance runners. Wall thickness measurements were normal in all three crewmembers preflight. Postflight basal studies were unchanged in the Commander on recovery day through 68 days postflight in both the Scientist Pilot and Pilot, however, the left ventricular end-diastolic volume, stroke volume, and mass were decreased slightly. Left ventricular function curves were constructed for the Commander and Pilot by plotting stroke volume versus end-diastolic volume. In both astronauts, preflight and postflight data fell on the same straight line demonstrating that no deterioration in cardiac function had occurred. These data indicate that the cardiovascular system adapts well to prolonged weightlessness and suggest that alterations in cardiac dimensions and function are unlikely to limit man's future in space

Microfabrication of Ceramics by Co-extrusion

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65777/1/j.1151-2916.1998.tb02307.x.pd