RESUMO
The capability to position individual emitters, such as quantum dots, near metallic nanostructures is highly desirable for constructing active optical devices that can manipulate light at the single photon level. The emergence of the field of plasmonics as a means to confine light now introduces a need for high precision and reliability in positioning any source of emission, which has thus far been elusive. Placing an emission source within the influence of plasmonic structures now requires accuracy approaching molecular length scales. In this paper we report the ability to reliably position nanoscale functional objects, specifically quantum dots, with sub-100-nm accuracy, which is several times smaller than the diffraction limit of a quantum dot's emission light. Electron beam lithography-defined masks on metallic surfaces and a series of surface chemical functionalization processes allow the programmed assembly of DNA-linked colloidal quantum dots. The quantum dots are successfully functionalized to areas as small as (100 nm)(2) using the specific binding of thiolated DNA to Au/Ag, and exploiting the streptavidin-biotin interaction. An analysis of the reproducibility of the process for various pattern sizes shows that this technique is potentially scalable to the single quantum dot level with 50 nm accuracy accompanied by a moderate reduction in yield.
Assuntos
Metais/química , Nanoestruturas/química , Pontos Quânticos , Algoritmos , DNA , Nanoestruturas/ultraestruturaRESUMO
Atrial fibrillation is the most common sustained arrhythmia likely to be encountered in clinical practice. It is associated with significant morbidity and mortality. The treatment of patients with atrial fibrillation can be complex and costly, especially when patients are hospitalized for acute management of this arrhythmia. In this review, we summarize current approaches to the acute management of atrial fibrillation with an emphasis on the most cost-effective approaches. We review acute methods of heart rate control and cardioversion, including pharmacologic and other minimally invasive strategies. We believe that the most cost-effective approaches may require the use of standardized clinical pathways. This may help to ensure that patients with acute atrial fibrillation receive the most effective and efficient care.
Assuntos
Antiarrítmicos/uso terapêutico , Fibrilação Atrial/terapia , Antiarrítmicos/economia , Fibrilação Atrial/economia , Fibrilação Atrial/mortalidade , Análise Custo-Benefício , Procedimentos Clínicos , Cardioversão Elétrica/economia , Cardioversão Elétrica/métodos , Humanos , Recidiva , Fatores de RiscoAssuntos
Permeabilidade do Canal Arterial/cirurgia , Custos Hospitalares , Modelos Econométricos , Procedimentos Cirúrgicos Torácicos/economia , Procedimentos Cirúrgicos Torácicos/métodos , Adolescente , Adulto , Cateterismo Cardíaco/economia , Criança , Pré-Escolar , Humanos , Lactente , Ligadura/economia , Pessoa de Meia-IdadeRESUMO
We have described the case of a patient with a renal thrombosis and renal infarction associated with cocaine use and protein C deficiency. We propose that patients with similar presentations receive a thorough evaluation for a hypercoagulable state, including protein C levels. Once the diagnosis is made, immediate intervention is required to protect renal function.
Assuntos
Cocaína , Infarto/etiologia , Rim/irrigação sanguínea , Artéria Renal , Transtornos Relacionados ao Uso de Substâncias/complicações , Trombose/etiologia , Adulto , Humanos , Masculino , Deficiência de Proteína CRESUMO
Byssochlamys fulva, isolated from corn, was grown on nutrient-amended shredded wheat medium for 14 days at 25 C. Crude solvent extract from these cultures was toxic to brine shrimp, chicken embryos, and rats. The extract was slightly inhibitory to the germination of of pea seeds, but was nontoxic to ten species of bacteria and one of yeast. One metabolite was isolated, given the trivial name byssotoxin A, and partially characterized chemically and physically.
