Amplified migration inhibition effect

Upon exposure to specific antigen in tissue culture, sensitive lymphocytes released macrophage migration inhibition factor and other lymphokines into the supernatant culture medium. Migration of peritoneal macrophages from nonsensitive animals was inhibited in the presence of such supernatants. However, with previous techniques it was found that an inhibitory effect was present at only low low titers (less than 10(2)). It is therfore of great interest that by increasing cellular density, the total number of cells being kept constant, inhibitory activity can be amplified by a factor as great as 10(10). This amplification was observed only when lymphocytes and macrophages were loosely packed, as by spontaneous sedimentation in a conical test tube. The effect was abolished by dispersing the cell suspension in a flat-bottomed flask or, alternatively, by shaking the test tube so that intimate prolonged intercellular contact was prevented.     

The effects of CO2 on the components of breathing pattern

Experiments were performed on 12 rabbits in 4 experimental groups: A. breathing spontaneously; B. nonparalysed and ventilated by means of a pump driven by the integrated phrenic nerve activity; C. paralysed and ventilated as mentioned above; D. like in the group C, but subjected to bilateral vagotomy. The relationships were investigated between the chosen basic parameters describing the rhythm and depth of respiration in steady states during exposure to hypercapnic mixtures. A high correlation was found between the amplitude of the integrated phrenic nerve activity and the time of inspiration which is modified by the afferent activities from the lungs and thorax TI and TE seem to be controlled by different mechanisms, and the contribution of TE to the control of the cycle duration is greater than that of TI.     

Strain Effects and Spalling in Alpha-Bombarded ThO2

Samples of bulk polycrystalline ThO₂ were bombarded with 5-MeV α-particles to doses between 9.4×10¹⁶ and 6.0×10¹⁷ ions/cm². The sample which received the highest dose spalled during bombardment; those receiving lower doses either did not spall or did so only after postirradiation annealing. The spalling was investigated by X-ray analysis and replica and transmission electron microscopy. It is concluded that spalling resulted from severe lattice strains at the interface between damaged and undamaged material and that sintering pores played a part in the fracture process. The role of lattice defects in initiating fracture is discussed.     

Morphological and physiological characteristics of Gemmiger formicilis isolated from chicken ceca

Morphological and physiological studies were made on chicken cecal isolates of the strictly anaerobic bacterial species Gemmiger formicilis. Structural features (phase-contrast and electron microscopy) of these microorganisms indicate they (i) are highly pleomorphic, (ii) possess a trilaminar cell wall like gram-negative bacteria, (iii) exhibit an unusual growth process characterized by polar swelling (resembling budding bacteria), and (iv) grow into elongated cells when exposed to a subinhibitory concentration of penicillin. The morphological data presented suggest that this species has a rod-shaped structure. These bacteria ferment a variety of sugars to produce formic, butyric, and lactic acids. There appear to be two groups of Gemmiger, one producing primarily lactate and the other producing formate as major fermentation metabolites. Growth of six strains in a basal medium, consisting of Trypticase, minerals, carbohydrate, Na2CO3 buffer, and cysteine as reducing agent, was stimulated by rumen fluid and yeast extract. Volatile fatty acids partially replaced the requirement for rumen fluid with some strains. Single deletions of vitamins (from a defined vitamin mixture) indicated that pantothenate, riboflavin, and thiamine were highly stimulatory to growth of the organism in a medium containing rumen fluid and Trypticase as source of vitamins. Other vitamin requirements were not studied.     

Defect Structure of NiO-CoO Solid Solutions

Measurements at high temperature of integrated intensities of Bragg peaks were used to examine the defect structure in two NiO-CoO solid solutions. The results indicate that the concentrations of vacant cation sites at 1100° to 1500°C are 4 to 10% and the tetrahedral occupations 2 to 5%. The concentration of these defects increases with temperature and partial pressure of O₂. The mean-square displacements of oxygen ions and cations increase with temperature and CoO concentration.     

Interdiffusion in CoO-NiO Solid Solutions

Interdiffusion coefficients were measured in CoO-NiO solid solutions over the range 1000° to 1600°C in air and at po₂=5×10⁻⁸ atm. Isothermal values of the interdiffusion coefficients in this system increased exponentially with the CoO concentration. Comparison of the present results with cation-tracer diffusion coefficients for this system measured under similar conditions by Chen and Peterson shows that a Darken-type equation relating the interdiffusion coefficient to the cation-tracer diffusivities is valid for these data.