Ab initio Computational Study of Quantum Plasmons in Graphene Nanoflakes

We investigate the potential merit in using nanometer-sized graphene flakes as building blocks of twodimensional (2D) quantum metamaterials. The choice of the building blocks is crucial to the design of quantum metamaterials with desired properties, graphene nano-structures being promising candidates towards this end. Thus, they can be grown either by bottom-up chemical synthesis or top-down electronbeam patterning in various shapes, densities, topology, and size, down to the molecular scale. We show that this versatility provides a wide range of parameters to tune the optical properties of graphene-based 2D quantum metamaterials

Quantum mechanical analysis of nonlinear optical response of interacting graphene nanoflakes

We propose a distant-neighbor quantum-mechanical (DNQM) approach to study the linear and nonlinear optical properties of graphene nanoflakes (GNFs). In contrast to the widely used tight-binding description of the electronic states that considers only the nearest-neighbor coupling between the atoms, our approach is more accurate and general, as it captures the electron-core interactions between all atoms in the structure. Therefore, as we demonstrate, the DNQM approach enables the investigation of the optical coupling between two closely separated but chemically unbound GNFs. We also find that the optical response of GNFs depends crucially on their shape, size, and symmetry properties. Specifically, increasing the size of nanoflakes is found to shift their accommodated quantum plasmon oscillations to lower frequency. Importantly, we show that by embedding a cavity into GNFs, one can change their symmetry properties, tune their optical properties, or enable otherwise forbidden second-harmonic generation processes

Standardization and chemical characterization of intravenous therapy in adult patients

Background: Intravenous drug administration is associated with potential complications, such as phlebitis. The physiochemical characteristics of the infusate play a very important role in some of these problems. Aim: The aim of this study was to standardize the dilutions of intravenous drugs most commonly used in hospitalized adult patients and to characterize their pH, osmolarity and cytotoxic nature to better guide the selection of the most appropriate vascular access. Methods: The project was conducted in three phases: (i) standardization of intravenous therapy, which was conducted using a modified double-round Delphi method; (ii) characterization of the dilutions agreed on in the previous phase by means of determining the osmolarity and pH of each of the agreed concentrations, and recording the vesicant nature based on the information in literature; and (iii) algorithm proposal for selecting the most appropriate vascular access, taking into account the information gathered in the previous phases. Results: In total, 112 drugs were standardized and 307 different admixtures were assessed for pH, osmolarity and vesicant nature. Of these, 123 admixtures (40%), had osmolarity values >600 mOsm/L, pH 9, or were classified as vesicants. In these cases, selection of the most suitable route of infusion and vascular access device is crucial to minimize the risk of phlebitis-type complications. Conclusions: Increasing safety of intravenous therapy should be a priority in the healthcare settings. Knowing the characteristics of drugs to assess the risk involved in their administration related to their physicochemical nature may be useful to guide decision making regarding the most appropriate vascular access and devices