Regeneration of the spinal ventral roots. An experimental study in cats

From a clinical standpoint recovery of spinal nerve roots is less likely than that of peripheral nerves, despite their identical structures. This may be due to several factors including the length of gap to be bridged, changes in the proximal stump or neuroma, and chromatolysis. In this paper we discuss the roles of some of these factors in relation to the neuronal depopulation in the spinal cord anterior horn area following section of the anterior root. The lack of growth or the successful growth of the axon through the gap in the root influences the degree of depopulation in the anterior horn area.     

Feeding deterrency of some pyrrolizidine,indolizidine, and quinolizidine alkaloids towards pea aphid (Acyrthosiphon pisum) and evidence for phloem transport of indolizidine alkaloid swainsonine

Journal of Chemical Ecology - The feeding deterrency of a series of pyrrolizidine, indolizidine, and quinolizidine alkaloids and selected derivatives was measured against the pea aphid...     

Design study of a 120-keV,3He neutral beam injector

We describe a design for a 120-keV, 2.3-MW,³He neutral beam injector for use on a D-³He fusion reactor. The constraint that limits operating life when injecting He is its high sputtering rate. The sputtering is partly controlled by using an extra grid to prevent ion flow from the neutralizer duct to the electron suppressor grid, but a tradeoff between beam current and operating life is still required. Hollow grid wires functioning as mercury heat pipes cool the grid and enable steady state operation. Voltage holding and radiation effects on the acceleration grid structure are discussed. We also briefly describe the vacuum system and analyze use of a direct energy converter to recapture energy from unneutralized ions exiting the neutralizer. Of crucial importance to the technical feasibility of the³He-burning reactor are the injector efficiency and cost; these are 53% and $5.5 million, respectively, when power supplies are included.The beam is composed of 91 separate, parallel currents that flow in the gaps between the elements or wires of a grid. Each such flow is referred to as a beamlet. The current densities in Figs. 5, 8, and 9 are values within a beamlet, as measured at the beam-forming grid. They are not values averaged over the entire beam cross-section.     

Analyses of rhythms of the body temperature in free running in rats

The objective of this study was to determine the disturbances of urea in serum and urine of endurance trained volunteers during prolonged exposure to hypokinesia (decreased number of km/day). The studies during hypokinesia (HK) were performed for 364 days on twenty long-distance runners in the age of 23 to 26 years, with an average peak oxygen uptake, of 66 ml.kg.min-1. All volunteers were divided into two equal groups: Ten volunteers were placed on a continuous regime of exercise 14.8 km/day and served as control subjects (CS). The remaining volunteers were subjected to continuous HK without the use of any preventive measures and were considered as the hypokinetic subjects (HS). For the simulation of the hypokinetic effect, the HS were kept continuously under an average of 2.7 km/day for the duration of the study. Prior to exposure to HK, the HS were on the same exercise regime as the CS. During a 60 day pre-HK period and during the experimental period, urinary excretion of urea, creatinine, sodium, potassium and calcium and concentrations thereof in serum were measured. In the HS the concentrations of urea, creatinine, sodium, potassium and calcium in serum and the rate of excretion thereof in urine increased significantly when compared to the CS. It was concluded that prolonged restriction of muscular activity induces significant disturbances of urea in serum and urine of endurance trained volunteers.