Thin film strength properties by indentation techniques

Using indentation techniques the micro-deformation of freely suspended, thin, evaporated films has been studied in slow loading and impact situations. The films were mounted on electron microscope grids and loads were applied in the unsupported regions between the grid bars. For the slow loading studies, measured loads were applied with the tip of a tungsten stylus, and impact was achieved by projecting small spherical particles against the specimens. Polycrystal and single-crystal silver films were studied; indentation shape and size effects were recorded for deformation under controlled loading conditions. It is suggested that the indentation method could be useful for rapidly comparing the strength properties of thin films.     

The long-term follow-up of patients with Klippel-Feil syndrome and congenital scoliosis

STUDY DESIGN: This study evaluated the long-term results of Klippel-Feil syndrome in patients with congenital scoliosis. OBJECTIVES: To determine the incidence of cervical and cervical-related symptoms of patients who have Klippel-Feil syndrome associated with congenital scoliosis. SUMMARY OF BACKGROUND DATA: Many authors have described the association of Klippel-Feil syndrome and congenital scoliosis. In this population of patients, cervical lesions often are discovered incidentally. The significance of these lesions is unknown. METHODS: Thirty-two patients with congenital scoliosis and Klippel-Feil syndrome were observed for more than 10 years. They were questioned specifically about cervical and cervical-related symptoms. All patients had sequential cervical radiographs and physical examinations. RESULTS: Despite rather dramatic radiographic appearances, only seven (22%) of the 32 patients had cervical or cervical-related symptoms, with two patients requiring surgery for their cervical lesions. The extent of the deformities and the average number of cervical vertebrae fused and cervical fusion-patterns were statistically similar between the symptomatic and asymptomatic groups. Patients fused to the cervicothoracic junction for management of their deformities had a significantly increased incidence of cervical symptoms. Also, patients with congenital stenosis had a significantly greater incidence of upper extremity pain. CONCLUSIONS: Only a small number of patients with Klippel-Feil syndrome and congenital scoliosis developed cervical symptoms. No fusion pattern that placed the patient at greater risk for developing symptoms could be identified. Factors that did lead to a greater incidence of cervical symptoms were fusion to the cervicothoracic junction and congenital cervical stenosis.     

The crystal structure of the liver fatty acid-binding protein. A complex with two bound oleates

The crystal structure of the recombinant form of rat liver fatty acid-binding protein was completed to 2.3 A and refined to an R factor of 19.0%. The structural solution was obtained by molecular replacement using superimposed polyalanine coordinates of six intracellular lipid-binding proteins as a search probe. The entire amino acid sequence of rat liver fatty acid-binding protein along with an amino-terminal formyl-methionine was modeled in the crystal structure. In addition, the crystal was obtained in the presence of oleic acid, and the initial electron density clearly showed two fatty acid molecules bound within a central cavity. The carboxylate of one fatty acid molecule interacts with arginine 122 and is shielded from free solvent. It has an overall bent conformation. The more solvent-exposed carboxylate of the other oleate is located near the helix-turn-helix that caps one end of the beta-barrel, while the acyl chain lies in the interior. The cavity contains both polar and nonpolar residues but also shows extensive hydrophobic character around the nonpolar atoms of the ligands. The primary and secondary oleate binding sites appear to be totally interdependent, mainly because favorable hydrophobic interactions form between both aliphatic chains.     

Effects of ergotamine on myocardial blood flow in migraineurs without evidence of atherosclerotic coronary artery disease

The effects of intravenous ergotamine (0.25 mg) on basal and hyperemic (dipyridamole) myocardial blood flow (MBF), measured with positron emission tomography and H2(15)O, were assessed in 15 migraineurs in a double-blind, randomized, placebo controlled, crossover study. Ergotamine produced a 27% reduction in hyperemic MBF (2.62 +/- 0.11 vs 3.72 +/- 1.05 ml x min(-1) x g(-1); p <0.05), a 31% reduction in the coronary vasodilator reserve (1.81 +/- 0.50 vs 2.71 +/- 1.15; p <0.01), and a 55% increase in minimal coronary resistance (42.2 +/- 15 vs 26.7 +/- 8 mm Hg x min x ml(-1) x g(-1); p <0.001), suggesting vasoconstriction of the coronary microcirculation.     

Scintillation effects receiving ATS-6 at 30 GHz

The 30 GHz signal which is received from the millimeter wave experiment on board the geostationary satellite ATS-6suffers from scintillation effects which are usually caused by refractive index fluctuations in the troposphere. The measurements show day and night differences with minima in the early morning and also differences depending on clear sky or cloudy sky. During rain the scintillations usually become smaller. Not only the copolar signal but also the crosspolar signal shows scintillation. In general, these fluctuations are larger than those of the copolar signal. A measuring set up will be shown for measuring the autocorrelation function of the scintillation signal. Knowing the autocorrelation function, the energy spectral density is known as both are a Fourier transform pair. The autocorrelation function is made visible on an oscilloscope and appears to be a function of time. By making a film the continuous changing picture of the auto correlation function is made visible.     

Comparing a mass-balance algorithm with a Bayesian regression analysis computer program for predicting serum phenytoin concentrations

The ability of a mass-balance algorithm to predict non-steady-state phenytoin concentrations in neurosurgery patients was compared with that of Phenda, a computerized Bayesian regression analysis program. Fifty neurosurgery patients who had had two or more initial phenytoin serum concentrations measured at least 60 hours apart and at least 1 hour after any i.v. doses, with the second concentration being not more than twice and not less than half of the first, and who had had a third or final phenytoin measurement (for use in a prediction analysis) were evaluated. The patients' maximum rates of metabolism were calculated by using the two initial phenytoin concentrations and a mass-balance algorithm, and the third phenytoin concentration was predicted. The patients' demographics and phenytoin dosages and concentrations were entered into Phenda, which was used to predict the third phenytoin concentration. The ability of the two methods to predict the third concentration was evaluated by the method of Sheiner and Beal. Fifty observations from 48 patients were evaluated. The mass-balance algorithm had a positive prediction bias of 2.52 mg/L and a precision error of 5.08 mg/L, compared with 2.30 and 5.30, respectively, for Phenda. The difference in the results between the two methods was not significant. There was no significant difference between the mass-balance algorithm and Phenda in the ability to predict phenytoin concentrations.     

Neural nets for adaptive filtering and adaptive pattern recognition

The adaptive linear combiner (ALC) is described, and practical applications of the ALC in signal processing and pattern recognition are presented. Six signal processing examples are given, which are system modeling, statistical prediction, noise canceling, echo canceling, universe modeling, and channel equalization. Adaptive pattern recognition using neural nets is then discussed. The concept involves the use of an invariance net followed by a trainable classifier. It makes use of a multilayer adaptation algorithm that descrambles output and reproduces original patterns