Effect of chlordiazepoxide on schedule-controlled responding and schedule-induced drinking

Polyovular follicles and polynuclear ova have been recorded to occur only in 5 goats out of 24 goats of ages between 2 months 24 days and 5 years 2 months 18 days, studied. These structures were recognized at proestrus, estrus and metestrus only but never in the animals over 1 year of age. Polyovular and polynuclear follicles with no apparent degenerative changes were seen at estrus whereas degenerating ones were commonly seen at proestrus and metestrus also.     

Effect of umbilical artery catheters on blood flow and oxygen supply to extremities

The effect of catheter placement in the abdominal aorta on the blood flow and oxygenation of lower extremities was evaluated in 30 New Zealand rabbits, weighing 0.55-3.5 kg, by inserting 3.5 and 5.0 French polyvinyl chloride catheters, of the type commonly used for umbilical artery catheterization, through the femoral artery, advancing 15-20 cm, and leaving in place for 10-30 min. Arterial blood pressure (BP), common iliac artery blood flow (BF), gracilis muscle tissue oxygen availability (O2a), and subcutaneous temperature (T) in the foot were continuously monitored before and during catheter placement and after withdrawal. There were no changes in the physiologic variables measured in the contralateral leg when the catheter remained below the aortic bifurcation; however, when the catheter was advanced 15-20 cm into the abdominal aorta, a decrease in lower extremity BF, O2a, and T occurred. Because the length of catheter insertion was maintained constant in each animal, the decreases in BF, O2a, and T are related to the relative dimensions of the vessel and the catheter. The ratio of catheter to vessel diamter, in addition to the site of catheter placement, should be considered during the clinical application of arterial catheters. Reduction in blood flow could be detected by continuous differential monitoring of core and extremity temperature or extremity muscle oxygen availability.     

Comparative change in the structure of superconductive Bi-4457 and (Bi−Pb)-4457 ceramics through explosive compaction

We conducted comparative research into superconductive Bi-4457 and (Bi–Pb)-4457 compacted ceramics. We noted that the addition of lead exerted a destabilizing effect on superconductivity and the correlation between restructuring of the crystal lattice and the superconductivity properties occurring with a change in the detonation pressure.Novosibirsk. Translated from Fizika Goreniya i Vzryva, No. 2, pp. 137–141, March–April, 1991.     

Variation of the heat resistance of the KhN35VT alloy with the transformation conditions of the solid solution

Conclusions 1.The transformation conditions (different cooling conditions) of the solid solution in the austenitic precipitation-hardening alloy KhN35VT strongly affect the strength and plastic characteristics in short-term and long-term tension. 2.Isothermal treatment with single-stage tempering increases the long-term plasticity 150\2-300% by comparison with the standard treatment and also increases the creep resistance and long-term strength, which is most notable at low stresses.In comparison with the same tempering after the standard treatment, two-stage tempering increases the plasticity and creep resistance by 200–300 and 200–500% respectively, while the long-term strenght remains at the same level or increases slightly. 3.After isothermal treatment with a low first tempering temperature (650\dgC) the impact strength after soaking at 650\dgC for 3500 h drops to approximately half its original value. With a high first tempering temperature (800\dgC) the impact strength decreases to a lesser extent-no lower than 6 kgm/cm². 4.It was confirmed that in double tempering of austenitic steels the first tempering temperature has a notable effect on the properties. The stability of the properties at working temperature depends on the proper conditions of the first tempering.Scientific Research and Design-Technological Institute of Machine Construction. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 2, pp. 26–32, February, 1968.