Assuntos
Conhecimentos, Atitudes e Prática em Saúde , Infecções por Mycobacterium/epidemiologia , Infecções por Mycobacterium/etiologia , Mycobacterium/patogenicidade , Médicos , Competência Profissional/estatística & dados numéricos , Estudantes de Medicina , Ponte Cardiopulmonar/efeitos adversos , HumanosRESUMO
We consider a central system which is coupled via dephasing to an open system, i.e. an intermediate system which in turn is coupled to another environment. Considering the intermediate and far environment as one composite system, the coherences in the central system are given in the form of fidelity amplitudes for a certain perturbed echo dynamics in the composite environment. On the basis of the Born-Markov approximation, we derive a master equation for the reduction of that dynamics to the intermediate system alone. In distinction to an earlier paper (Moreno et al 2015 Phys. Rev. A 92, 030104. (doi:10.1103/PhysRevA.92.030104)), where we discussed the stabilizing effect of the far environment on the decoherence in the central system, we focus here on the possibility of using the measurable coherences in the central system for probing the open quantum dynamics in the intermediate system. We illustrate our results for the case of chaotic dynamics in the near environment, where we compare random matrix simulations with our analytical result.
Assuntos
Dermatopatias/patologia , Picada de Aranha/patologia , Aranhas , Combinação Amoxicilina e Clavulanato de Potássio/uso terapêutico , Animais , Ácido Fusídico/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Dermatopatias/tratamento farmacológico , Picada de Aranha/tratamento farmacológicoRESUMO
OBJECTIVE: To investigate whether heparin produces vasodilation in human veins and to explore the underlying mechanisms. METHODS: Eleven healthy volunteers were studied with the dorsal hand vein compliance technique. Dose-response curves to heparin and enoxaparin were generated. Dose-response curves to heparin were also constructed before and after heparin was infused with the nitric oxide synthase inhibitor N(G)-monomethyl-l-arginine (L-NMMA) or combined histamine H1- and H2-receptor blockade. RESULTS: Heparin but not enoxaparin caused significant dose-dependent relaxation with an average apparent maximal response (at an infusion rate of 20 IU/min) of 47% +/- 23%. L-NMMA attenuated heparin-induced relaxation (P < .001). The combination of H1-and H2-receptor antagonists attenuated heparin-induced relaxation to a lesser extent (P < .05). Heparin-induced relaxation decreased by 52%, 73%, and 35% in the presence of L-NMMA, indomethacin (INN, indometacin) plus L-NMMA, and combined H1- and H2-receptor blockade, respectively. CONCLUSION: Heparin is an endothelium-dependent venodilator in humans. The mechanism of heparin-induced relaxation involves an increased availability of nitric oxide, possibly partially related to local release of histamine.
