Changes in host animal plasma lipids during hepatoma growth

The concentrations of the major neutral lipid and phospholipid classes in the plasma of rats bearing hepatoma 7288CTC were determined at various times after transplantation. The fatty acid composition of each lipid class was also analyzed quantitatively as tumor growth progressed. Generally, most lipid classes exhibited a slight decrease between the third and sixth day after transplantation, returned to near normal levels by the 15th day, increased dramatically and peaked between the 24th and 27th days before plummeting sharply. At peak concentrations, triglycerides were increased 5 times the normal levels, whereas cholesterol, cholesteryl esters and phosphatidylcholines were increased 3-fold. The percentage of hexadecenoates decreased in all lipid classes as tumor growth progressed and generally, stearate levels increased. In addition to monounsaturated fatty acids, lysophosphatidylcholines and phosphatidylcholines showed relatively large decreases in the percentages of polyunsaturated fatty acids with increased tumor growth. These results indicate that hepatoma 7288CTC can cause perturbation of host animal plasma lipids in the early stages of growth which precedes the massive hyperlipidemia. The interpretation of these results suggests that the early changes in plasma lipids may result from alterations in the normal lipid metabolism of the host, and the hyperlipidemia that develops later may result from the mobilization of lipids to compensate for the altered metabolism. This paper was given by M. Matocha as an Honored Student Award presentation at the AOCS meeting, San Francisco, CA, April 29–May 31, 1979. This work has been submitted in partial fulfillment of the requirement for the M.S. degree.     

Effect of liquid content on distortion and rearrangement densification of liquid-phase-sintered W-Cu

Tungsten and copper exhibit negligible solubility for each other, so densification during liquid phase sintering of W-Cu is limited to rearrangement of the W particles and solid-state sintering of the W skeleton. Experiments are conducted to evaluate the effects of Cu volume fraction on liquid phase sintering of W-Cu. Sintered microstructures are quantitatively analyzed and are used to define critical microstructural parameters that prevent distortion and rearrangement densification. Slumping is prevented first by capillary forces, then by formation of a rigid W skeleton at critical values of contiguity and connectivity, which depend on the dihedral angle. A refined expression for the dependence of contiguity on volume fraction that includes the effect of the dihedral angle is developed. An analysis of gravitational, capillary, and bonding forces acting on W particles in liquid Cu explains the ability to achieve high sintered densities through rearrangement despite a lack of distortion with up to 80 vol pct liquid. Capillary forces are sufficient to break weak solid-solid bonds that form during heating, enabling rearrangement to occur even without dissolution of these bonds. At higher solid volume fractions, sufficient particle contacts form to prevent rearrangement by these capillary forces, thus limiting sintered densities.     

An Investigation Demonstrating the Feasibility of Microwave Sintering of Base-Metal-Electrode Multilayer Capacitors

A microwave sintering technique has been developed for base-metal electrode (BME) multilayer ceramic capacitors (MLCCs). Commercial green chips of size 0603 MLC with nickel electrodes were sintered in a microwave field. With a specially designed susceptor/insulation package to optimize coupling and uniformity of heating, a number of sintering experiments were conducted in the temperature range of 1200 to 1250∘C in a multimode microwave cavity operating at 2.45 GHz under a partially reducing atmosphere. Microstructure of the microwave processed MLCCs was investigated with both SEM and TEM techniques. The dielectric properties of the microwave sintered MLCCs were measured and compared with those sintered using conventional process at 1320∘C and lower pO₂’s ≈ 10^{− 9} atms. The results demonstrate that nickel electrodes remain metallic after microwave sintering even though the pO₂’s were relatively high and would thermodynamically favor NiO. The microwave sintered samples showed a dense, fine and uniform microstructure. The properties of the microwave-sintered samples were comparable to the conventionally sintered samples. The microwave processing was found to have enhanced sintering kinetics of the BME MLCCs, lowering sintering temperature by about 100∘C and also the processing time by about 90%.     

Biochemical changes involved in a lesion-induced behavior in the cat.

Previous investigations on cats with pontile lesions established that 2 metabolic changes are involved in an abnormal grooming behavior: a rhythmic dysfunction in the systemic glucocorticoid level and a decrease in the activity of the enzyme, tryptophan hydroxylase, in the superior colliculus. In the present study, these 2 metabolic changes were approximated in 14 male cats without pontile lesions by adrenalectomy and by enzyme inhibition with parachlorophenylalanine. These 2 metabolic changes in Ss with intact brains produced the same abnormal behavior found previously in cats with pontile lesions, thus providing evidence for the biochemical mediation of a lesion-induced behavioral change. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Toward an Understanding of Nonverbal Communication Systems

An introduction to this special issue of The Journal of Communication, the following article sketches current trends in nonverbal communication and provides a backdrop for the succeeding contributions. While the study of nonverbal communication has ancient roots, a rapid growth of empirical research has taken place in recent years. The guest editors touch on some of the theoretical issues, especially in defining “nonverbal communication.” In addition, they point to developments on the research front. Finally, they conclude that the study of nonverbal communication is a robust and fast-moving field, with a strong potential for growth and application.     

Motor-unit activity responsible for 8- to 12-Hz component of human physiological finger tremor

Tremor of the extended third digit and bipolar surface and needle electromyograms of the extensor digitorum were recorded from six healthy volunteers for the purpose of elucidating the motor-unit activity responsible for the 8- to 12-Hz component of physiological finger tremor. Tremor was measured with a force transducer during steady voluntary contractions of approximately 200-250 g. The surface EMGs were full-wave rectified and low-pass filtered (-3 dB at 21 Hz), producing the envelope of the surface EMG (the demodulated EMG). Spectral analyses of simultaneous tremor and demodulated EMG records were performed. In four of six subjects, a pronounced 8- to 12-Hz amplitude modulation in the surface EMG was present, and coherency analysis demonstrated that this modulation was strongly correlated with the well-known 8- to 12-Hz tremor. In two subjects this amplitude modulation and tremor were barely detectable, despite the sensitive recording and analysis techniques used in this study. Spectral analysis was performed on 43 motor-unit spike trains. Twenty-two spike trains, having mean firing frequencies in the range of 10-22 spikes/s, produced statistically significant spectral peaks at 8-12 Hz, in addition to the expected spectral peaks at the mean firing frequencies. Of the 22 8- to 12-Hz-producing motor units, 12 had mean firing frequencies in the range of 17-22 spikes/s and exhibited the greatest 8- to 12-Hz activities of all motor units recorded. These motor units displayed transient sequences of double discharges in which interspike intervals (ISIS) of approximately 8-30 ms alternated with ISIS of 60-90 ms, thus producing an 8- to 12-Hz spectral peak. Adjacent ISIS of these motor units were correlated in the range of -0.5 to -0.9. Coherency analyses demonstrated that the 8- to 12-Hz activities of these motor units were correlated with the 8- to 12-Hz finger tremor and surface EMG modulation. The remaining 10 8- to 12-Hz-producing motor units had mean firing frequencies in the range of 10-17 spike/s. Although these motor units did not display the intense double-discharge firing pattern of the more rapidly firing motor units, a tendency toward action potential grouping was present and resulted in 8- to 12-Hz spectral activities which were correlated with the tremor and surface EMG modulation. .. ..