Novel Tetrazine Organometallic Complexes for Nonlinear Optical Switching: a Combined Density Functional Theory and Experimental Study

Over the past decade, mono- and bi- and oligonuclear organometallic complexes have been deal of great interest by material chemists and engineers due to their remarkable nonlinear optical (NLO), magnetic and electric properties. [1] They were furthermore envisaged as powerful candidates for quantum computing, molecular devices and more interestingly as molecular switches. The definition of molecular switch implies that a compound should have two interconvertable stable forms that have a significant difference in the magnitude of, at least, one of their physico-chemical properties. [2] In the case of organometallic complexes the most expedite way to achieve such interconversion is by redox means, where one takes advantage of the different oxidations states allowed by a single or multiple metal centers that interact with each other, and with the ligands therein. It is known that the choice of an appropriate π-bridging system between the metal centers is crucial to obtain the adequate electronic environment for efficient metal-to-metal and metal-to-ligand interactions, and hence fine tune the optical, electric and magnetic macroscopic properties. Mixed-valance metal complexes from group VIII, particular Fe(II)/Fe(III) and Ru(II)/Ru(III) systems [3,4], have been successfully synthesized as stable species that possess strong metal-to-ligand charge transfer (MLCT) and inter-valence charge transfer (IVCT) absorption bands in visible and NIR regions, respectively.[5, 6] This is the case of the well known Creutz-Taube ion [(H3N)5Ru(m-pz)Ru(NH3)5]5+ (pz=pyrazine) and related compounds. Substituted 1,2,4,5-tetrazine (tz) strongly enhance both the stability and the MLCT and IVCT phenomenon’s since they act as a strong π-acceptor and can stimulate the metal-to-metal interaction. [6] In this work, we present our ongoing studies in the use of substituted 1,2,4,5-tetrazine (tz) ligands as the π-bridge between two transition metal centers, both experimentally and by means of Density Functional Theory (DFT). Synthesis and characterization by NMR, voltammetric and UV-Vis. spectra are presented. The DFT calculations were used to evaluate the nature of the electronic transitions as well as the switching of the NLO properties. The compounds showed to be great candidates for NLO switching since the magnitude of such property can change upon redox stimulus at the metal centers

Contributions to the ontology of aging, the sensitive indicators of rehabilitation nursing care, in terms of self-care, in people with respiratory disorders

With the increase in the average life expectancy, the appearance of chronic diseases and, in particular, in the respiratory forum and its disadvantages in the autonomy and self-care of patients, brought an important paradigm for health care and, in particular, rehabilitation nursing, with implications for the development of ontologies of aging. Thus, it is imperative to systematize them in scientifically measurable indicators to demonstrate the benefit that rehabilitation nursing brings to improve patients' quality of life, thus ensuring excellence. Each area of scientific health should contribute to the construction of aging ontology. Objective: to identify indicators sensitive to nursing care of rehabilitation, in terms of self-care, in relation to those with respiratory pathology, to be integrated into the ontology of aging. Methods: A systematic review of the literature was performed using the EBSCO (full-text MEDLINE, CINAHL, Full-Text Plus, British Nursing Index), using the PI [C] O method with 6 emergent articles. Results: A total of 20 indicators were identified, including: Ability to perform activities, increase physical and functional independence, symptom management, reduction of complications, increase in quality of life, which can be allocated as a proposal for classes of the aging ontology. Conclusion: Knowledge of indicators sensitive to nursing care recognition of the importance of rehabilitation nursing in increasing self-care and autonomy for people with respiratory pathology, and research in this area is fundamental for its effectiveness and efficiency, and its integration in the ontologies of aging is fundamental

A proposal of sensitive indicators of the rehabilitation nursing care of people in the surgical process, to be included in the ontology of aging

Given the complex surgical scenario observed today, it is necessary to change the urgent definition of a specific ontology, especially in terms of aging. The interventions of the Specialist Nurse in Rehabilitation Nursing to the person in the surgical process are primordial for the maintenance of the functional capacities, prevention of complications and impediment of incapacities. However, it is necessary to provide individualized and fostered care in a practice of excellence, and the consequent organized reading of records of an aging ontology for decision making on rehabilitation indicators. Method: a systematic review of the literature was carried out using the EBSCO host (MEDLINE with Full Text, CINAHL Plus with Full Text and MedicLatina), using the PI [C] O method, and 11 articles were selected. Results: 41 indicators were identified to be included in the ontology classes of aging: pain control, patient and family education, support and communication, reduction of postoperative complications, gain of functionality, restoration of physical function, mobility, multidisciplinary intervention and the frequency of interventions. Conclusion: it is considered that it was imperative to identify sensitive indicators for rehabilitation nursing care, based on scientific evidence and thus provide an opportunity for nurses to reflect on their daily practices and conduct their actions towards excellence in care, to propose a set of 41 classes internationally on the ontology of aging

Language as an Evolving Word Web

Human language can be described as a complex network of linked words. In such a treatment, each distinct word in language is a vertex of this web, and neighboring words in sentences are connected by edges. It was recently found (Ferrer and Sol\'e) that the distribution of the numbers of connections of words in such a network is of a peculiar form which includes two pronounced power-law regions. Here we treat language as a self-organizing network of interacting words. In the framework of this concept, we completely describe the observed Word Web structure without fitting.Comment: 4 pages revtex, 2 figure

Time of avalanche mixing of granular materials in a half filled rotated drum

The avalanche mixing of granular solids in a slowly rotated 2D upright drum is studied. We demonstrate that the account of the difference $\delta$ between the angle of marginal stability and the angle of repose of the granular material leads to a restricted value of the mixing time $\tau$ for a half filled drum. The process of mixing is described by a linear discrete difference equation. We show that the mixing looks like linear diffusion of fractions with the diffusion coefficient vanishing when $\delta$ is an integer part of $\pi$. Introduction of fluctuations of $\delta$ supresses the singularities of $\tau(\delta)$ and smoothes the dependence $\tau(\delta)$.Comment: 4 pages revtex (twocolumn, psfig), 2 figure