Enhancing single-parameter quantum charge pumping in carbon-based devices

We present a theoretical study of quantum charge pumping with a single ac gate applied to graphene nanoribbons and carbon nanotubes operating with low resistance contacts. By combining Floquet theory with Green's function formalism, we show that the pumped current can be tuned and enhanced by up to two orders of magnitude by an appropriate choice of device length, gate voltage intensity and driving frequency and amplitude. These results offer a promising alternative for enhancing the pumped currents in these carbon-based devices.Comment: 3.5 pages, 2 figure

Floquet bound states around defects and adatoms in graphene

Recent studies have focused on laser-induced gaps in graphene which have been shown to have a topological origin, thereby hosting robust states at the sample edges. While the focus has remained mainly on these topological chiral edge states, the Floquet bound states around defects lack a detailed study. In this paper we present such a study covering large defects of different shape and also vacancy-like defects and adatoms at the dynamical gap at $\hbar\Omega/2$ ($\hbar\Omega$ being the photon energy). Our results, based on analytical calculations as well as numerics for full tight-binding models, show that the bound states are chiral and appear in a number which grows with the defect size. Furthermore, while the bound states exist regardless the type of the defect's edge termination (zigzag, armchair, mixed), the spectrum is strongly dependent on it. In the case of top adatoms, the bound states quasi-energies depend on the adatoms energy. The appearance of such bound states might open the door to the presence of topological effects on the bulk transport properties of dirty graphene.Comment: 16 pages, 14 figure

Floquet interface states in illuminated three-dimensional topological insulators

Recent experiments showed that the surface of a three dimensional topological insulator develops gaps in the Floquet-Bloch band spectrum when illuminated with a circularly polarized laser. These Floquet-Bloch bands are characterized by non-trivial Chern numbers which only depend on the helicity of the polarization of the radiation field. Here we propose a setup consisting of a pair of counter-rotating lasers, and show that one-dimensional chiral states emerge at the interface between the two lasers. These interface states turn out to be spin-polarized and may trigger interesting applications in the field of optoelectronics and spintronics.Comment: 5 pages with 3 figures + supplemental materia

How to develop internal innovation in the media: A case study of best practices for media outlet

The goals intended are to analyze media outlets from the inside, to provide some guidelines on the best practices for media companies that want to shape/reshape their business to survive and grow in the currently troubled media ecosystem. The main questions are to understand how legacy media in Portugal are facing the changing media ecosystem, in special how are they using any kind of internal innovation strategies to outcome the decreasing of sales and/or audiences and advertising revenues. We also pretend to frame this national reality into a broader picture, contextualizing the analysis. So we pose the following questions: are the Portuguese media outlets seeking internal innovation to face and outcome the fall of traditional business models? How legacy media can change from the inside? What processes are they creating/recreating that affect the news production and dissemination? What processes are they creating/recreating that affect the revenue stream? How the Portuguese media ecosystem compares to the international best practices? What guidelines can be identified to help legacy media or journalistic startups to survive in a troubled sea? To achieve the objectives we use non-participatory observation on three Portuguese newsrooms, and interview some of its managers/editorial managers, chosen by its diversity: a TV network that includes, among others, a free-to-air legacy TV channel with the most viewed eight o’clock news program and a 24/7 TV news channel; a national broadcast news radio; an online only newspaper. All three have their online operations, via website and apps. Both the TV and the radio are legacy media that, through different approaches and rhythms, are reshaping their business models, news production processes and news product. Both have internal innovation strategies that we observe, register and analyze. The online newspaper was born has an online only operation, not needing to transform from a legacy/analog operation, but still develops internal innovation strategies to evolve in an always moving digital media landscape. The study cases are built from framed analysis and previous academic work produced by authors like Lucy Kung, Ramón Salaverría, Anderson, Bell & Shirky, Mark Deuze, Bastos & Zamith, Paul Bradshaw, Adelino Gomes, Gureskin, Seave & Graves, Lowe, Gregory & Brown, Storsul, Tanja & Krumsvik, Janine Warner or Barbie Zelizer. So we try to identify the focus on the practices inside the Portuguese case studies, internal innovation strategies on newsrooms, entrepreneurial strategies to change from the traditional business model and boost the financial results. We also try to deliver and promote some guidelines to media outlets that want to innovate and/or to entrepreneurs wanting to create journalistic startups, and to boost the discussion about the need to improve the internal mechanisms of change to survive in a troubled media ecosystem.info:eu-repo/semantics/acceptedVersio

Imaging of biliary involvement in sarcoidosis: Computed tomography, magnetic resonance cholangiopancreatography, and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging findings

Sarcoidosis is a multisystem disease usually affecting the chest, hilar lymph nodes, and lungs, but can potentially involve any organ; therefore, its clinical presentation may vary. Hepato-biliary involvement is rare, and typically asymptomatic; however, it can lead to cirrhosis, and may require liver transplantation. In this report, we present a rare case of a patient affected by sarcoidosis with hepatobiliary involvement. He presented to our hospital complaining of dyspnea triggered by moderate efforts and oppressive thoracic discomfort. Chest X-ray showed multiple bilateral nodular opacities and enlargement of both hilar regions, confirmed by a subsequent total-body computed tomography scan and positron emission tomography, which also revealed cardiac, splenic, and hepatic involvement. Liver function was studied via gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging, and magnetic resonance cholangiopancreatography (MRCP) was also performed. The diagnosis of sarcoidosis was finally achieved via liver biopsy, revealing non-necrotizing granulomas in the periportal space. The patient was treated with prednisone per os, with regression of all lesions at all levels. Although other cases of biliary sarcoidosis have been described, this report provides a complete image set of Gd-EOB-DTPA-enhanced magnetic resonance and MRCP images that is lacking in the English literature, and which may be useful for diagnosis

Co-targeting of Bcl-2 and mTOR pathway triggers synergistic apoptosis in BH3 mimetics resistant acute lymphoblastic leukemia

Several chemo-resistance mechanisms including the Bcl-2 protein family overexpression and constitutive activation of the PI3K/Akt/mTOR signaling have been documented in acute lymphoblastic leukemia (ALL), encouraging targeted approaches to circumvent this clinical problem. Here we analyzed the activity of the BH3 mimetic ABT-737 in ALL, exploring the synergistic effects with the mTOR inhibitor CCI-779 on ABT-737 resistant cells. We showed that a low Mcl-1/Bcl-2 plus Bcl-xL protein ratio determined ABT-737 responsiveness. ABT-737 exposure further decreased Mcl-1, inducing apoptosis on sensitive models and primary samples, while not affecting resistant cells. Co-inhibition of Bcl-2 and the mTOR pathway resulted cytotoxic on ABT-737 resistant models, by downregulating mTORC1 activity and Mcl-1 in a proteasome-independent manner. Although Mcl-1 seemed to be critical, ectopic modulation did not correlate with apoptosis changes. Importantly, dual targeting proved effective on ABT-737 resistant samples, showing additive/synergistic effects. Together, our results show the efficacy of BH3 mimetics as single agent in the majority of the ALL samples and demonstrate that resistance to ABT-737 mostly correlated with Mcl-1 overexpression. Co-targeting of the Bcl-2 protein family and mTOR pathway enhanced drug-induced cytotoxicity by suppressing Mcl-1, providing a novel therapeutic approach to overcome BH3 mimetics resistance in ALL

Multiterminal conductance of a floquet topological insulator

We report on simulations of the dc conductance and quantum Hall response of a Floquet topological insulator using Floquet scattering theory. Our results reveal that laser-induced edge states lead to quantum Hall plateaus once imperfect matching with the nonilluminated leads is lessened. The magnitude of the Hall plateaus, however, is not directly related to the number and chirality of all the edge states at a given energy, as usual. Instead, the plateaus are dominated by those edge states adding to the time-averaged density of states. Therefore, the dc quantum Hall conductance of a Floquet topological insulator is not directly linked to topological invariants of the full Floquet bands.publishedVersionFil: Foa Torres, Luis Eduardo Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Foa Torres, Luis Eduardo Francisco. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Pérez Piskunow, Pablo Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Física Enrique Gaviola; Argentina.Fil: Pérez Piskunow, Pablo Matías. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina.Fil: Balseiro, Carlos A. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina.Fil: Balseiro, Carlos A. Comisión Nacional de Energía Atómica. Instituto Balseiro; Argentina.Fil: Balseiro, Carlos A. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Usaj, Gonzalo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina.Fil: Usaj, Gonzalo. Comisión Nacional de Energía Atómica. Instituto Balseiro; Argentina.Fil: Usaj, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Física de los Materiales Condensado

Subacute pericardial abscess after aortic valve replacement: a case report

BACKGROUND: Purulent pericarditis is an infectious disease, frequently caused by gram-positive bacteria, that is rarely observed in healthy individuals, and is often associated with predisposing conditions. CASE PRESENTATION: Here, we present the case of an Escherichia coli post-surgical localized purulent pericarditis complicated by transient constrictive pericarditis and its diagnostic and therapeutic management. CONCLUSIONS: Our case report focuses on the importance of imaging-guided treatment of purulent pericardial diseases, in particular on the emerging role of 18\u2009F-labelled 2-fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography in pericardial diseases and on the management of transient constrictive pericarditis, often seen after thoracic surgery

Modeling graphene-based nanoelectromechanical devices

We report on a theoretical study of charge transport properties of graphene nanoribbons under external mechanical stress. The influence of mechanical forces on the ribbon conductance is shown to be strongly dependent on the ribbon edge symmetry, i.e., zigzag versus armchair. In contrast to zigzag-edge nanoribbons which remain robust against high strain deformations, a stretching-induced metal-semiconductor transition is obtained for armchair-edge configurations. Our results point out that armchair edge ribbons are consequently much better suited for electromechanical applications.Fil: Poetschke, M.. Technische Universität Dresden; AlemaniaFil: Rocha, C. G.. Technische Universität Dresden; AlemaniaFil: Foa Torres, Luis Eduardo Francisco. Universidad Nacional de Córdoba. Facultad de Matemática, Astronomía y Física; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; ArgentinaFil: Roche, Serge. Technische Universität Dresden; Alemania. Universite Grenoble Alpes. Institut Nanosciences et Cryogenie - Commissariat a L´Energie Atomique et Aux Energies Alternatives. Institut Nanosciences et Cryogenie; Francia. Centro de Investigación en Nanociencia y Nanotecnología (CIN2); EspañaFil: Cuniberti, G.. Technische Universität Dresden; Alemani

The feasibility of prolonged exposure therapy for PTSD in low-and middle-income countries: a review

There is a need in the global south to evaluate and implement empirically supported psychological interventions to ameliorate symptoms of posttraumatic stress disorder (PTSD). Empirically supported treatments (ESTs) have increasingly been developed and implemented, yet the majority people in the global south do not have access to these treatments for mental disorders such as PTSD. Prolonged exposure therapy has accrued substantial empirical evidence to show it as an effective treatment for PTSD. Research on the effectiveness and acceptability of prolonged exposure in a low- and middle-income countries (LMICs) are sparse. This brief report presents a review of prolonged exposure (PE) therapy and its feasibility as a trauma therapy for PTSD in LMICs. First, we present a brief overview of PE as a first-line treatment for PTSD. Second, using South Africa as a case example, we present a brief overview of traumatic stress in South Africa and how mental healthcare has developed since the abolishment of apartheid in 1994. Lastly, we discuss the challenges pertaining to the dissemination and implementation of PE in LMICs and propose future perspectives regarding the implementation of ESTs such as PE in LMICs