Modelli informativi “predigitali” e loro recenti sviluppi. Dal Raumbuch al BIM

The digital tools are usually more efficient, as much as a solid sorting logic is consolidated behind them. This logic is often formed through a long practice with similar non-digital tools. This paper presents a comparative discussion between BIM and Raumbuch, as tools for survey, study and design for heritage buildings. A early history of Raumbuch is summarized and some of the foundamentals of such technical tools are discussed. The Raumbuch is a tool for analysing and sorting huge amounts of information about a building. It originated in late XIX century, within a field of application between architecture and archaeology. The Raumbuch has more recently been spread as a tool for organizing a building survey or design. Heritage buildings have represented a specific field of application. Many experiences have concurred to consolidate and refine this methodology, particularly in the German speaking area. Some controversial outputs may also emerge when Raumbich has being developed basing on a building information modeling. A cross-fertilization process has to be encouraged to overcome language differences and some cultural laziness. Research will achieve positive results

Implications of apixaban for dental treatments

Anticoagulation therapy is used in several conditions to prevent or treat thromboembolism. Recently, new oral anticoagulants have been introduced as alternatives to warfarin and acenocoumarol. In Europe, the European Medicines Agency has approved dabigatran, rivaroxaban and apixaban. Their advantages include: predictable pharmacokinetics, drug interactions and limited food, rapid onset of action and short half-life. However, they lack a specific reversal agent. A literature search was conducted through November 2015 for publications in the ISI Web of Knowledge, PubMed, Scopus and Cochrane Library using the keywords “apixaban”, “rivaroxaban”, “dabigatran”, “new oral anticoagulants”, “dental treatment” and “dental implications”. We included studies published in English and Spanish over the last 10 years. Apixaban has been recently introduced in the daily medical practices for the control of thromboembolism. The number of patients taking apixaban is increasing. Management of patients on anticoagulation therapy requires that dentists can accurately assess the patient prior to dental treatments. It is important for dentists to have a sound understanding of the mechanisms of action and management guidelines for patients taking new oral anticoagulants. The dentist should consider carefully the management of patients on apixaban. This paper sets out a clinical guidance of dental practitioners treating these patients. There is a need for further clinical studies in order to establish more evidence-based guidelines for dental patients requiring apixaban

Strong antenna-enhanced fluorescence of a single light-harvesting complex shows photon antibunching

The nature of the highly efficient energy transfer in photosynthetic light-harvesting complexes is a subject of intense research. Unfortunately, the low fluorescence efficiency and limited photostability hampers the study of individual light-harvesting complexes at ambient conditions. Here we demonstrate an over 500-fold fluorescence enhancement of light-harvesting complex 2 (LH2) at the single-molecule level by coupling to a gold nanoantenna. The resonant antenna produces an excitation enhancement of circa 100 times and a fluorescence lifetime shortening to ~\n20 ps. The radiative rate enhancement results in a 5.5-fold-improved fluorescence quantum efficiency. Exploiting the unique brightness, we have recorded the first photon antibunching of a single light-harvesting complex under ambient conditions, showing that the 27 bacteriochlorophylls coordinated by LH2 act as a non-classical single-photon emitter. The presented bright antenna-enhanced LH2 emission is a highly promising system to study energy transfer and the role of quantum coherence at the level of single complexes

Optical emission near a high-impedance mirror

Solid state light emitters rely on metallic contacts with high sheet-conductivity for effective charge injection. Unfortunately, such contacts also support surface plasmon polariton (SPP) excitations that dissipate optical energy into the metal and limit the external quantum efficiency. Here, inspired by the concept of radio-frequency (RF) high-impedance surfaces and their use in conformal antennas we illustrate how electrodes can be nanopatterned to simultaneously provide a high DC electrical conductivity and high-impedance at optical frequencies. Such electrodes do not support SPPs across the visible spectrum and greatly suppress dissipative losses while facilitating a desirable Lambertian emission profile. We verify this concept by studying the emission enhancement and photoluminescence lifetime for a dye emitter layer deposited on the electrodes

Boosting Fluorescence-Based Chiral Sensing with Nanophotonics

The handedness of chiral molecules can be detected in their circularly polarized fluorescence, which is typically very weak. Here, we propose dielectric nanophotonics to increase both the fluorescence intensity and polarization contrast

Optical antennas control light emission

The emission of light is at the heart of both fundamental science and technological applications. At its origin lie electronic transitions in nanoscale materials such as molecules, atoms and semiconductors. The interaction of light with such single quantum emitters is inefficient because of their point-like character. Efficient interfaces between light and nanoscale matter are therefore necessary. Inspired by the effective communication between small electronic circuits enabled by radio-frequency antenna technology, an emitter can be addressed efficiently with a nanoantenna, an optical element that converts localized energy into propagating radiation. The control of light emission with such optical antennas is the topic of this Thesis. By coupling an emitter to a metal antenna, the emission properties are determined by the antenna mode in direction, transition rates, polarization, and spectrum. In Chapter 1, we set out the basic concepts of optical antenna theory. To couple an emitter to an antenna, it must be within its near field. In Chapter 2, we introduce a nanofabrication method to place quantum dots on metal nanostructures with high spatial accuracy. The resulting emitter-antenna systems are imaged by confocal microscopy and their angular radiation patterns directly recorded. This combination of experimental methods allows us to study any optical antenna. A metal wire is the canonical antenna design and the basis to understand and construct other optical antennas. Through selective coupling of a quantum dot to the resonant modes of a nanowire, we demonstrate in Chapter 3 that the emission of a dipolar source can be converted controllably into higher multipolar radiation. We describe the antenna as a standing-wave resonator for plasmons and reproduce its emission with a multipolar expansion. An aperture in a metal film can be regarded as the complementary structure of a wire. In Chapter 4, we address the emission of light through a rectangular nanoaperture as an antenna problem. We demonstrate, explicitly, that resonant nanoslot antennas display a magnetic dipole response. Such antennas offer an efficient interface between emitters and surface plasmons. The excitation or detection of a dipolar emitter from the far field involves large solid angles. To address quantum emitters efficiently, a low divergence of their radiation patterns is needed. To this end, in Chapter 5 we develop and realize unidirectional optical antennas. We show how the emission of a quantum emitter is directed by multi-element Yagi-Uda and log-periodic optical antennas and demonstrate directional operation of a single-element design based on a splitring resonator. Light emission usually occurs through electric dipole transitions because multipolar emission rates are orders of magnitude slower. In some materials, however, multipolar optical transitions do occur. In Chapter 6, we assess through simulations the feasibility of enhancing magnetic dipole and electric quadrupole transitions with several realistic nanoantenna designs. The results in this Thesis demonstrate the potential of optical antennas as elements to control light on the nanoscale, based on radio and microwave antenna engineering. Within this powerful paradigm, the interaction of light with nanoscale matter can be tailored with complete flexibility. Such a degree of control over light emission and absorption may have a practical impact in spectroscopy, sensing, display technologies, lighting, photovoltaics, and general optical and optoelectronic devices.La emisión de luz radica en el corazón tanto de la ciencia fundamental como de varias aplicaciones tecnológicas. En su origen están las transiciones electrónicas en nanomateriales como moléculas, átomos y semiconductores. La interacción de la luz con uno de estos emisores cuánticos es ineficiente debido a su carácter puntual. Es necesario, por tanto, desarrollar interfaces más eficientes entre la luz y la materia de tamaño nanoscópico. Inspirándonos en la comunicación entre pequeños circuitos electrónicos que permiten las antenas de radio, se puede interactuar más eficientemente con un emisor utilizando una nanoantena como elemento óptico que convierte la energía localizada en radiación propagante. Esta Tesis trata sobre el control de la emisión de luz con tales antenas ópticas. Acoplando un emisor a una antena metálica, las propiedades de la emisión pasan a estar determinadas por el modo de la antena en dirección, tasas de transición, polarización y espectro. En el Capítulo 1, establecemos las nociones básicas de la teoría de antenas ópticas. Para acoplar un emisor a una antena, éste debe encontrarse en su campo cercano. En el Capítulo 2, presentamos un método de nanofabricación para posicionar puntos cuánticos sobre nanoestructuras metálicas con alta resolución espacial. Para caracterizar los sistemas emisor-antena resultantes, adquirimos imágenes mediante microscopía confocal y medimos sus patrones angulares de radiación. Esta combinación de métodos experimentales nos permite el estudio de cualquier antena óptica. El diseño canónico de una antena es un cable metálico. Es la base para entender y construir otras antenas ópticas. Mediante acoplamiento selectivo de un punto cuántico a los modos resonantes de un nanocable, en el Capítulo 3 demostramos que la emisión de una fuente dipolar puede ser convertida en radiación multipolar controladamente. Describimos la antena como un resonador de onda estacionario para plasmones y reproducimos su emisión con una expansión multipolar Se puede considerar una apertura en una película metálica como la estructura complementaria de un cable. En el Capítulo 4, tratamos la emisión de luz a través de una apertura rectangular como un problema de antenas. Demostramos, explícitamente, que una nano-ranura resonante posee respuesta dipolar magnética. Estas antenas permiten una conversión eficiente entre emisores de fotones y plasmones superficiales. La excitación o detección de un emisor dipolar conlleva ángulos sólidos grandes. Para abordar un emisor cuántico individual eficientemente desde el campo lejano, se requieren patrones angulares con una baja divergencia. Con estre fin, en el Capítulo 5 desarrollamos e implementamos antenas ópticas unidireccionales. Demostramos cómo la emisión de un emisor cuántico puede ser dirigida por antenas multi-elemento de Yagi-Uda y logarítmicas periódicas y observamos direccionalidad en una antena compuesta por un único elemento con forma de diapasón. La emisión de luz ocurre normalmente a través de transiciones de dipolo eléctrico porque las tasas de emisión multipolares son, por lo general, mucho más lentas. Sin embargo, en algunos materiales se pueden observar transiciones multipolares. En el Capítulo 6, evaluamos la posibilidad de mejorar la emisión de transiciones dipolares magnéticas y cuadrupolares eléctricas mediante distintos diseños realistas de antenas ópticas. Los resultados de esta Tesis demuestran el potencial de las antenas ópticas como elementos para el control de la luz a escalas nanométricas, basadas en la ingeniería de antenas de radio y microondas. Dentro de este paradigma, se puede manipular la interacción de la luz con la materia con total flexibilidad. Tal grado de control sobre la emisión y la absorción de la luz podría tener un gran impacto práctico en espectroscopía, sensores, pantallas, iluminación, energía fotovoltaica y todo tipo de dispositivos ópticos y optoelectrónico

Dental management of patients taking novel oral anticoagulants (NOAs): dabigatran

A new group of oral anticoagulants (dabigatran, rivaroxaban, apixaban and edoxaban) with clear advantages over classic dicoumarin oral anticoagulants (warfarin and acenocoumarol) has been developed in recent years. Patients being treated with oral anticoagulants are at higher risk for bleeding when undergoing dental treatments. A literature search was conducted through April 2016 for publications in the ISI Web of Knowledge, PubMed and Cochrane Library using the keywords “dabigatran”, “rivaroxaban”, “apixaban”, “edoxaban”, “new oral anticoagulants”, “novel oral anticoagulants”, “bleeding” and “dental treatment”. There is no need for regular coagulation monitoring of patients on dabigatran therapy. Whether or not to temporarily discontinue dabigatran must be assessed according to the bleeding risk involved in the dental procedure to be performed. The number of patients under treatment with new oral anticoagulants will increase in the coming years. It is essential to know about the pharmacokinetics and pharmacodynamics of new oral anticoagulants and about their interactions with other drugs. It is necessary to develop clinical guidelines for the perioperative and postoperative management of these new oral anticoagulants in oral surgical procedures, and to carefully evaluate the bleeding risk of dental treatment, as well as the thrombotic risk of suppressing the new oral anticoagulant

Cutaneous collagenous vasculopathy: papular form

Cutaneous collagenous vasculopathy is a rare clinicopathological entity, first described in 2000. Cutaneous collagenous vasculopathy has been considered a form of microangiopathy of superficial dermal vessels and produce lesions that appear as telangiectasia. We present a patient with histopathologic features of cutaneous collagenous vasculopathy and scattered erythematous papules on the trunk with a striking dermatoscopic finding. We propose the term of 'cutaneous papular collagenous vasculopathy' as a new clinical manifestation of this disease

Contrast in spin-valley polarization due to competing indirect transitions in few-layer WS2_2 and WSe2_2

Controlling the momentum of carriers in semiconductors, known as valley polarization, is a new resource for optoelectronics and information technologies. Materials exhibiting high polarization are needed for valley-based devices. Few-layer WS$_2$ shows a remarkable spin-valley polarization above 90%, even at room temperature. In stark contrast, polarization is absent for few-layer WSe$_2$ despite the expected material similarities. Here, we explain the origin of valley polarization in both materials due to the interplay between two indirect optical transitions. We show that the relative energy minima at the $\Lambda$- and K-valleys in the conduction band determine the spin-valley polarization of the K-K transition. Polarization appears as the energy of the K-valley rises above the $\Lambda$-valley as a function of temperature and number of layers. Our results advance the understanding of the high spin-valley polarization in WS$_2$. This insight will impact the design of both passive and tunable valleytronic devices operating at room temperature.Comment: 22 pages, 6 figures, 2 table

Enhanced light emission by magnetic and electric resonances in dielectric metasurfaces

We demonstrate an enhanced emission of high quantum yield molecules coupled to dielectric metasurfaces formed by periodic arrays of polycrystalline silicon nanoparticles. Radiative coupling of the nanoparticles, mediated by in-plane diffraction, leads to the formation of collective Mie scattering resonances or Mie surface lattice resonances (M-SLRs), with remarkable narrow line widths. These narrow line widths and the intrinsic electric and magnetic dipole moments of the individual Si nanoparticles allow to resolve electric and magnetic M-SLRs. Incidence angle- and polarization-dependent extinction measurements and high-accuracy surface integral simulations show unambiguously that magnetic M-SLRs arise from in- and out-of-plane magnetic dipoles, while electric M-SLRs are due to in-plane electric dipoles. Pronounced changes in the emission spectrum of the molecules are observed, with almost a 20-fold enhancement of the emission in defined directions of molecules coupled to electric M-SLRs, and a 5-fold enhancement of the emission of molecules coupled to magnetic M-SLRs. These measurements demonstrate the potential of dielectric metasurfaces for emission control and enhancement, and open new opportunities to induce asymmetric scattering and emission using collective electric and magnetic resonances.Comment: 27 pages with 9 figure