RESUMO
In this paper we analyze the atomic-level structure of solid/liquid interfaces of Lennard-Jones fcc systems. The 001, 011, and 111 faces are examined during steady-state growth and melting of these crystals. The mechanisms of crystallization and melting are explored using averaged configurations generated during these steady-state runs, where subsequent tagging and labeling of particles at the interface provide many insights into the detailed atomic behavior at the freezing and melting interfaces. The interfaces are generally found to be rough and we observe the structure of freezing and melting interfaces to be very similar. Large structural fluctuations with solidlike and liquidlike characteristics are apparent in both the freezing and melting interfaces. The behavior at the interface observed under either growth or melting conditions reflects a competition between ordering and disordering processes. In addition, we observe atom hopping that imparts liquidlike characteristics to the solid side of the interfaces for all three crystal faces. Solid order is observed to extend as rough, three-dimensional protuberances through the interface, particularly for the 001 and 011 faces. We are also able to reconcile our different measures for the interfacial width and address the onset of asymmetry in the growth rates at high rates of crystal growth/melting.
RESUMO
Etomidate compares favourably with methohexitone as an intravenous induction agent in out-patient anaesthesia excluding the incidence of involuntary muscle movement. The use of propylene glycol as a solvent for etomidate does not alter the previously claimed advantageous features of this agent.
Assuntos
Anestesia Intravenosa , Etomidato , Imidazóis , Metoexital , Sistema Cardiovascular/efeitos dos fármacos , Ensaios Clínicos como Assunto , Método Duplo-Cego , Etomidato/administração & dosagem , Etomidato/farmacologia , Feminino , Humanos , Imidazóis/administração & dosagem , Imidazóis/farmacologia , Masculino , Metoexital/administração & dosagem , Metoexital/farmacologia , Pessoa de Meia-Idade , Propilenoglicóis/administração & dosagem , Respiração/efeitos dos fármacosRESUMO
The introduction of polyethylene glycol as a solvent for etomidate appears to markedly reduce the incidence of pain on injection while maintaining the previously demonstrated advantageous features of cardiovascular stability and rapid recovery.
Assuntos
Anestesia Intravenosa , Etomidato , Imidazóis , Pressão Sanguínea/efeitos dos fármacos , Ensaios Clínicos como Assunto , Etomidato/administração & dosagem , Etomidato/efeitos adversos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Imidazóis/administração & dosagem , Masculino , Contração Muscular/efeitos dos fármacos , Dor/induzido quimicamente , Polietilenoglicóis/farmacologiaRESUMO
Induction of anaesthesia with the new short acting agent etomidate has been studied in 200 patients undergoing urological outpatient procedures. These patients exhibited a similar pattern of recovery to those receiving 7 mg/kg propanidid but had greater cardiac and respiratory stability. However, there was a 25% incidence of pain which was reduced to 13-9% by increasing the rate of injection from 30 to 15 seconds. The incidence of involuntary movements was 29-7% which was reduced to 15% by the faster rate of injection. The omission of atropine premedication did not affect cardiac stability. Etomidate appears to have many desirable features as an induction agent except for a high incidence of pain on injection which is reduced by rapid injection.
