RESUMEN
More fundamental knowledge of coal (knowledge of its structure and its behavior during conversion processes) is essential before we can generate new technologies necessary for the efficient use of coal in the future. Herein are suggested specific basic research opportunities in the areas of coal characterization, gasification, combustion, and liquefaction, along with an assessment of the impact such research programs could have. Critical characterization needs include qualitative and quantitative determination of the chemical forms of carbon, oxygen, nitrogen, and sulfur and reliable methods for the measurement of surface area, pore volume, and weight-average molecular weights. Mechanistic studies aimed at increasing understanding of the thermal breakdown of the functionalities in coal, the behavior of coal in the presence of molecular and donor hydrogen environments, and carbon gasification and hydrocarbon synthesis reactions starting from carbon monoxide and hydrogen will lay the scientific foundation for the development of new processes for converting coal into clean usable fuels and chemicals.
Asunto(s)
Aerosoles , Pulmón/metabolismo , Ensayos Clínicos como Asunto , Humanos , Fotograbar , Radioisótopos , XenónAsunto(s)
Computadores , Pulmón/metabolismo , Fotograbar , Xenón/metabolismo , Velocidad del Flujo Sanguíneo , Humanos , RadioisótoposAsunto(s)
Medicina Tropical , Adolescente , Adulto , Anciano , Amebiasis/diagnóstico , Infecciones por Cestodos/diagnóstico , Femenino , Filariasis/diagnóstico , Helmintiasis/diagnóstico , Infecciones por Uncinaria/diagnóstico , Humanos , Leishmaniasis/diagnóstico , Lepra/diagnóstico , Malaria/diagnóstico , Masculino , Esquistosomiasis/diagnóstico , Escocia , Estrongiloidiasis/diagnósticoAsunto(s)
Medicina Tropical , Amebiasis/diagnóstico , Encefalitis Japonesa/diagnóstico , Femenino , Enfermedades de los Genitales Femeninos/diagnóstico , Cardiopatías/diagnóstico , Helmintiasis/diagnóstico , Humanos , Parasitosis Intestinales/diagnóstico , Kuru/diagnóstico , Lepra/diagnóstico , Enfermedades Pulmonares Parasitarias/diagnóstico , Malaria/diagnóstico , Masculino , Manifestaciones Neurológicas , Esquistosomiasis/diagnóstico , Enfermedades Cutáneas Parasitarias/diagnóstico , Enfermedades Urológicas/diagnósticoRESUMEN
Following the production of digitalis toxicity in dogs as manifested by ventricular tachycardia, the pharmacokinetics of lidocaine treatment of the arrhythmia were determined during pentobarbitone anaesthesia and pentobarbitone-halothane anaesthesia. The elimination rate constants, beta and Ke, and the biological half life T1/2beta were statistically significantly increased during halothane anaesthesia. The volume of distribution was unchanged. The results indicate that the therapeutic loading dose of lidocaine need not be altered during halothane anaesthesia but if a constant infusion is used, the rate of infusion would have to be decreased four fold to avoid toxic plasma levels of lidocaine.
Asunto(s)
Glicósidos Digitálicos/toxicidad , Halotano/farmacología , Lidocaína/farmacología , Animales , Perros , Ventrículos Cardíacos , Cinética , Lidocaína/sangre , Lidocaína/uso terapéutico , Taquicardia/inducido químicamente , Taquicardia/tratamiento farmacológicoRESUMEN
Bis-[p-nitrophenyl] phosphate, BNPP, an enzyme inhibitor of the organophosphate class, has been used to inhibit the enzyme, carboxylic ester hydrolase EC 3.1.1.1. Esterases play a major role in the rapid metabolism of propanidid in vivo; in fact, the short duration of action of this intravenous anesthetic agent is due to this rapid hydrolysis. The duration of anesthesia with propanidid alone in healthy mongrel dogs was 10.1 +/- 2.1 (SEM) minutes. When the dogs were pretreated with BNPP, propanidid anesthesia time was prolonged to 38.2 +/- 7.9 (SEM) minutes. Measurements of serum propanidid concentration demonstrated that prolonged high levels of propanidid were associated with the extended anesthesia time. Therefore, BNPP can significantly alter the anesthetic action of propanidid by inhibition of the enzyme system responsible for the rapid hydrolysis of the agent. The experimental model used in the present study provides a means for investigation of effects of certain drugs when their metabolism is impaired.