RESUMO
Intact molecular ions of the organothiolate-protected nanoparticle Au25(SCH2CH2Ph)18, including their isotopic resolution, can be observed at 7391 Da as 1- and 1+ ions in negative and positive mode, respectively, by MALDI-TOF mass spectrometry when using a tactic of threshold laser pulse intensities and trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile (DCTB) as matrix. Previous MALDI-TOF studies of Au nanoparticles using other matrices have encountered extensive fragmentation of nanoparticle as well as thiolate ligands. Absence of fragmentation enables precise determination of the distribution of mixed monolayer compositions on nanoparticles prepared by ligand exchange reactions and by synthesis using thiol mixtures. Reaction conditions producing mixed monolayers containing only one or a small number of usefully functional ligands can be readily identified. At increased laser pulse intensity, the first fragmentation step(s) for the Au25(SCH 2CH2Ph)18 nanoparticle results in losses of AuL units and, in particular, loss of Au4(SCH2CH2Ph)4.
RESUMO
BACKGROUND: The essence of medicine is a relationship based upon a concern for suffering. Western medicine, arising from a modernistic philosophy, has a tradition of paternalistic 'doctor centred' care. There are significant criticisms of this approach. OBJECTIVE: Drawing on postmodern perspectives, this article discusses the nature of patient centred care. Patient centred care requires a reconciliation of the patient's and doctor's agenda via attention to communication, power and patient autonomy. Patient centred care has been defined by six domains: the illness experience, the context, finding common ground, partnership, health promotion, and consultation limitations. DISCUSSION: Patients strongly desire patient centred care. It has been associated with improved patient and doctor satisfaction, greater compliance, fewer investigations, referrals and malpractice complaints, and no change in consultation time. Patient centred care exerts a positive influence on health outcomes and is especially applicable in general practice, providing an efficacious and compassionate response to suffering.
