92 research outputs found
Effect of Stretch Orientation and Rolling Orientation on the Mechanical Properties of 2195 Al-Cu-Li Alloy
Sheets of 2195 aluminum-lithium alloy were solution-treated at 507 A degrees C for 30 min. One set was stretched to 3-5% in the 0A degrees, 45A degrees, and 90A degrees angle with respect to the original rolling direction. Two other sets were rolled 6% reduction in thickness and 24% reduction in thickness in the 0A degrees, 45A degrees, and 90A degrees angle with respect to the original rolling direction. All specimens were aged at 143 A degrees C for 36 h. A second group of samples was rolled at 24 and 50% reduction in thickness after a solution treatment of 507 A degrees C for 1 h prior to aging at 190 A degrees C for 24 h. Tensile specimens were machined from each sheet at 0A degrees, 45A degrees, and 90A degrees angles to the original grain orientation. Tensile testing was used to determine the mechanical properties and anisotropic behavior of each condition. Rolling 6% reduction in thickness in the 45A degrees orientation yielded anisotropy of 7.6% in the yield strength
Adsorption Isotherms of Hydrogen: The Role of Thermal Fluctuations
It is shown that experimentally obtained isotherms of adsorption on solid
substrates may be completely reconciled with Lifshitz theory when thermal
fluctuations are taken into account. This is achieved within the framework of a
solid-on-solid model which is solved numerically. Analysis of the fluctuation
contributions observed for hydrogen adsorption onto gold substrates allows to
determine the surface tension of the free hydrogen film as a function of film
thickness. It is found to decrease sharply for film thicknesses below seven
atomic layers.Comment: RevTeX manuscript (3 pages output), 3 figure
Cocaethylene: A neuropharmacologically active metabolite assciated with concurrent cocaine-ethanol ingestion
High concentrations of cocaethylene (EC), the ethyl ester of benzoylecgonine, were measured in the blood of individuals who had concurrently used cocaine and ethanol. Since the powerful reinforcing effects of cocaine appear to be dependent on inhibition of dopamine reuptake in brain, we compared the effects of EC on the dopamine uptake system and its behavioral effects with those of cocaine. EC was equipotent to cocaine with respect to inhibition of binding of [3H]GBR 12395 to the dopamine reuptake complex, inhibition of [3H]dopamine uptake into synaptosomes and in its ability to increase extracellular dopamine concentration in the nucleus accumbens following its systemic administration to rats. Moreover, in rats, EC and cocaine each increased locomotor activity and rearing to the same extent following i.p. administration. In self-administration studies in primates, EC was approximately equipotent to cocaine in maintaining responding. The in vivo formation of this active, transesterified ethyl homolog of cocaine may contribute to the effects and consequences of combined cocaine and ethanol abuse.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29671/1/0000760.pd
Serotonergic Attenuation of the Reinforcing and Neurochemical Effects of Cocaine in Squirrel Monkeys
Increased Mortality in Metal-on-Metal versus Non-Metal-on-Metal Primary Total Hip Arthroplasty at 10 Years and Longer Follow-Up: A Systematic Review and Meta-Analysis
Analysis and Stochastic
Luminescent lanthanide cyclen-based enzymatic assay capable of diagnosing the onset of catheter-associated urinary tract infections both in solution and within polymeric hydrogels
Herein
we present a supramolecular (delayed luminescent) EuÂ(III)-based
pH-responsive probe/sensor with the ability to detect the urease-mediated
hydrolysis of urea in aqueous solution. A series of photophysical
titrations show this EuÂ(III) chelate behaves as an “<i>on–off</i>” luminescent switching probe, with
its luminescence being quenched upon urea being enzymatically converted
into ammonia and carbon dioxide. Calculation of the rate constant
(<i>k</i>) and activation energy (<i>E</i><sub>a</sub>) for this hydrolysis reaction are detailed; the results demonstrate
a direct observation of enzymatic activity in solution by the sensor.
The potential application of this probe in detecting the onset of
catheter-associated urinary tract infections (CAUTIs) is also demonstrated
by incorporating <b>1.Eu</b> into water-permeable hydrogels
that can be utilized as an alternative coating for catheters
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