On the criteria for instrumental autonomic conditioning: A reply to Katkin and Murray.

In their recent review of instrumental conditioning of autonomic functions, E. S. Katkin and E. N. Murray (see 42: criticized most of the existing studies on the human level as artifactual on 1 or more grounds. The criteria they employed for rejecting these demonstrations are themselves open to criticism, however. Specifically, it is argued that (1) peripheral or cognitive mediation hypotheses are unlikely alternative explanations of the obtained results; (2) an increase in response frequency over a preconditioning operant level is not a necessary condition for demonstrating an increase in response probability with contingent reinforcement; and (3) yoked-control designs, frequently used in this research, do not automatically invalidate experiments in which they are employed. It is concluded that the strongest hypothesis to account for the existing data remains the direct instrumental strengthening of autonomic activity. (35 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overview: Signal production and detection.

Studies of signal production and detection are complicated by the diverse modalities used by animals, constraints of human signal perception, and limitations of a controlled laboratory environment. These complications can be addressed by creative approaches to studying anatomical adaptations for signal production and detection, innovative technology, and careful studies of signal production and detection in the field. These solutions should overcome the perceptual limitations of researchers as they explore Umwelten in other species. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Synthesis and evaluation of morpholinoalkyl ester prodrugs of indomethacin and naproxen

Morpholinoalkyl esters (HCl salts) of naproxen 1 and indomethacin 3 were synthesized and evaluated in vitro and in vivo for their potential use as prodrugs for oral delivery. Prodrugs were freely soluble in simulated gastric fluid (SGF) and pH 7.4 phosphate buffer and showed a minimum of a 2000-fold increase in solubility over the parent drugs. All prodrugs were more lipophilic than parent drugs as indicated by n-octanol/pH 7.4 buffer partition coefficients but less lipophilic in terms of n-octanol/SGF partition coefficients. Potentiometrically determined pKa's for prodrugs were in the range of 6.89 to 8.62 at 25 degrees C. All prodrugs were quantitatively hydrolyzed to their respective parent drugs by enzymatic and/or by chemical means. An increase in carbon chain length rendered the prodrugs more stable at pH 7.4 but less stable in SGF. The esters were generally found to be hydrolyzed rapidly in rat plasma at 37 degrees C, the half-lives being in the range of 1.2-31.0 min. Based on in vitro results, prodrugs 2c and 4c were chosen to evaluate solid-state stability, in vivo bioavailability, and ulcerogenicity. At elevated temperatures, the solid-state decomposition of 2c and 4c followed biphasic kinetics, with rapid decomposition occurring initially. The prodrugs were 30-36% more bioavailable orally than the parent drugs following a single equimolar solution dose in rats. Prodrugs 2c and 4c were significantly less irritating to gastric mucosa than parent drugs following single-dose and chronic oral administration in rats.     

A model for the diffusion of vinyl chloride monomer from PVC under various conditions of storage

This example of employee safety activity in the vinyl resin industry is illustrative of the efforts put forth by many to achieve acceptable VCM levels in work areas during all conditions of handling. Since use conditions differ greatly at temperatures above T_g temperatures and are nonstatic, it was deemed necessary to develop a model embracing many variables to allow prediction of atmospheric vinyl chloride monomer levels for any combination of the variables.     

Interaction of tail-pressure stress and d-amphetamine in disruption of the rat's ability to ignore an irrelevant stimulus.

48 male Sprague-Dawley rats received either 0 or 30 preexposures to a tone that was later used as a warning stimulus in a 2-way active avoidance task. Consistent with previous data, tone preexposure resulted in retarded acquisition of the conditioned avoidance response (CAR) in saline-control Ss and in Ss that received chronic administration of dextroamphetamine (DAM; 1 mg/kg, sc). Ss that received tail-pressure stress prior to stimulus preexposure also showed retarded acquisition of the CAR. However, Ss that received a combination of tail pressure and DAM did not show retarded CAR acquisiton following stimulus preexposure. Results suggest an interaction between environmental stressors and DAM in producing attentional deficits. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Minicomputers Used in Metering and Leak Detection Systems for Liquid Petroleum Products Pipelines

The use of minicomputers as part of a product metering system is new and relatively expensive. The use of minicomputers is discussed from the following: 1) its advantage, practical limitations and disadvantages; 2) Colonial Pipeline Company's approach and design of computer aided metering systems for certain locations. Computer controlled leak detection is discussed from the following: 1) summary of leak detection systems to date with success and problems of each; 2) Colonial Pipeline Company's use of a minicomputer to control 10 independent lateral lines using pressure drop, flow rate, meter-in versus meter-out to automatically shut down the line and close out as required. Design of the system, operating procedures, problems, and evaluation are discussed.     

Sonography of patellar abnormalities in children

OBJECTIVE: We describe our experience using sonography to evaluate the patella and patellofemoral joint in three children with congenital abnormalities of the extensor mechanism of the lower extremity. CONCLUSION: Sonography can be used to evaluate the extensor mechanism and unossified patella in young children. Advantages of sonography over MR imaging are no need for sedation, speed of examination and ability to compare with the contralateral knee, low cost, and the sonographer's ability to dynamically evaluate the extensor mechanism.