RESUMEN
Polyethylene (C2H4)n was compressed to pressures between 10 and 30 GPa in a diamond anvil cell (DAC) and laser heated above 2500 K for approximately one second. This resulted in the chemical decomposition of the polymer into carbon and hydrocarbon reaction products. After quenching to ambient temperature, the decomposition products were measured in the DAC at pressures ranging from ambient to 29 GPa using a combination of x-ray diffraction (XRD) and small angle x-ray scattering (SAXS). XRD identified cubic diamond and methane as the predominant product species with their pressure-volume relationships exhibiting strong correlations to the diamond and methane equations of state. Length scales associated with the diamond products, obtained from SAXS measurements, indicate the formation of nanodiamonds with a radius of gyration between 12 and 35 nm consistent with 32-90 nm diameter spherical particles. These results are in good agreement with the predicted product composition under thermodynamic and chemical equilibrium.
RESUMEN
After the accidental ascent of a diving bell from 80 m, one diver died from pulmonary barotrauma and the other-though grossly ill-survived. After recompression therapy, this diver was tetraplegic with evidence of patchy microcirculatory damage of brain, cord, liver, kidneys, and gut. All systems eventually returned to normal, except the spinal cord, mainly because of the post-recompression phase of management, in which pharmacological doses of steroids, hyperbaric oxygen, and dextran were used. Although function returned in the upper limbs, the diver remained paraplegic.
Asunto(s)
Enfermedad de Descompresión/terapia , Buceo , Accidentes , Adulto , Volumen Sanguíneo , Enfermedad de Descompresión/fisiopatología , Dextranos/uso terapéutico , Humanos , Oxigenoterapia Hiperbárica , Enfermedades Pulmonares/etiología , Metilprednisolona/uso terapéutico , Insuficiencia Respiratoria/terapia , Enfermedades de la Médula Espinal/etiologíaRESUMEN
A study of the physical dimensions of the rabbit tenuissimus muscle is described and compared with previous work on the same muscle from the cat. The muscle in the rabbit was found to be larger than in the cat, but was consistent in its dimensions and suitable for use as a model for microvascular research.
