Internal screening and dielectric engineering in magic-angle twisted bilayer graphene

Magic-angle twisted bilayer graphene (MA-tBLG) has appeared as a tunable testing ground to investigate the conspiracy of electronic interactions, band structure, and lattice degrees of freedom to yield exotic quantum many-body ground states in a two-dimensional Dirac material framework. While the impact of external parameters such as doping or magnetic field can be conveniently modified and analyzed, the all-surface nature of the quasi-2D electron gas combined with its intricate internal properties pose a challenging task to characterize the quintessential nature of the different insulating and superconducting states found in experiments. We analyze the interplay of internal screening and dielectric environment on the intrinsic electronic interaction profile of MA-tBLG. We find that interlayer coupling generically enhances the internal screening. The influence of the dielectric environment on the effective interaction strength depends decisively on the electronic state of MA-tBLG. Thus, we propose the experimental tailoring of the dielectric environment, e.g. by varying the capping layer composition and thickness, as a promising pursuit to provide further evidence for resolving the hidden nature of the quantum many-body states in MA-tBLG.Comment: 9 pages, 3 figures, supplemental material included (8 figures

Doping fingerprints of spin and lattice fluctuations in moiré superlattice systems

Twisted Van der Waals systems offer the unprecedented possibility to tune different states of correlated quantum matter with external noninvasive electrostatic doping. The nature of the superconducting order presents a recurring open question in this context. In this work, we assess quantitatively the case of spin-fluctuation-mediated pairing for Γ-valley twisted transition metal dichalcogenide homobilayers. We calculate self-consistently and dynamically the doping-dependent superconducting transition temperature Tc revealing a superconducting dome with a maximal Tc≈0.1–1K depending on twist angle. We compare our results with conventional phonon-mediated superconductivity, and we identify clear fingerprints in the doping dependence of Tc, which enable experiments to distinguish between different pairing mechanisms

Identifying the optimal spatial distribution of tracers for optical sensing of stream surface flow

River monitoring is of particular interest as a society that faces increasingly complex water management issues. Emerging technologies have contributed to opening new avenues for improving our monitoring capabilities but have also generated new challenges for the harmonised use of devices and algorithms. In this context, optical-sensing techniques for stream surface flow velocities are strongly influenced by tracer characteristics such as seeding density and their spatial distribution. Therefore, a principal research goal is the identification of how these properties affect the accuracy of such methods. To this aim, numerical simulations were performed to consider different levels of tracer clustering, particle colour (in terms of greyscale intensity), seeding density, and background noise. Two widely used image-velocimetry algorithms were adopted: (i) particle-tracking velocimetry (PTV) and (ii) particle image velocimetry (PIV). A descriptor of the seeding characteristics (based on seeding density and tracer clustering) was introduced based on a newly developed metric called the Seeding Distribution Index (SDI). This index can be approximated and used in practice as SDI = nu(0.1)/(rho/rho(c nu 1)), where nu, rho, and rho(c nu 1 )are the spatial-clustering level, the seeding density, and the reference seeding density at nu = 1, respectively. A reduction in image-velocimetry errors was systematically observed for lower values of the SDI; therefore, the optimal frame window (i.e. a subset of the video image sequence) was defined as the one that minimises the SDI. In addition to numerical analyses, a field case study on the Basento river (located in southern Italy) was considered as a proof of concept of the proposed framework. Field results corroborated numerical findings, and error reductions of about 15.9 % and 16.1 % were calculated - using PTV and PIV, respectively - by employing the optimal frame window

Myoepithelioma of minor salivary gland on the base of the tongue: a case report

This study reports a case of myoepithelioma of minor salivary gland on the base of the tongue of a 58 year-old patient. This theme is discussed because it is a rare tumor, and in this case, it was located in an uncommon position. The diagnosis was given by the pathologic and immunohistochemical study of the excised tumor. The course is usually benign, and the cure is possible if it is completely excised.Os autores apresentam um caso de mioepitelioma de glândula salivar menor, localizado na base da língua de uma paciente de 58 anos. O mioepitelioma é um tumor pouco freqüente, de evolução benigna, sendo possível obter-se a cura através da excisão cirúrgica completa da lesão. Neste caso, apresentou-se numa posição bastante incomum, a base da língua. Foi realizada a exérese da lesão, com margens de segurança, e a paciente está assintomática e sem recidiva local depois de 6 meses de acompanhamento pós-operatório. O diagnóstico foi obtido através do estudo anatomopatológico e imuno-histoquímico da peça.Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM)Universidade Federal de São Paulo (UNIFESP), Escola Paulista de Medicina (EPM) Departamento de Otorrinolaringologia e Distúrbios da Comunicação HumanaUNIFESP, EPM, Depto. de Otorrinolaringologia e Distúrbios da Comunicação HumanaSciEL

Probiotic bacteria regulate intestinal epithelial permeability in experimental ileitis by a TNF-dependent mechanism

Background: We previously showed that the probiotic mixture, VSL#3, prevents the onset of ileitis in SAMP/YitFc (SAMP) mice, and this effect was associated with stimulation of epithelial-derived TNF. The aim of this study was to determine the mechanism(s) of VSL#3-mediated protection on epithelial barrier function and to further investigate the "paradoxical" effects of TNF in preventing SAMP ileitis. Methods: Permeability was evaluated in SAMP mice prior to the onset of inflammation and during established disease by measuring transepithelial electrical resistance (TEER) on ex vivo-cultured ilea following exposure to VSL#3 conditioned media (CM), TNF or VSL#3-CM + anti-TNF. Tight junction (TJ) proteins were assessed by qRT-PCR, Western blot, and confocal microscopy, and TNFRI/TNFRII expression measured in freshly isolated intestinal epithelial cells (IEC) from SAMP and control AKR mice. Results: Culture with either VSL#3-CM or TNF resulted in decreased ileal paracellular permeability in pre-inflamed SAMP, but not SAMP with established disease, while addition of anti-TNF abrogated these effects. Modulation of the TJ proteins, claudin-2 and occludin, occurred with a significant decrease in claudin-2 and increase in occludin following stimulation with VSL#3-CM or TNF. TNF protein levels increased in supernatants of SAMP ilea incubated with VSL#3-CM compared to vehicle, while IEC-derived TNFR mRNA expression decreased in young, and was elevated in inflamed, SAMP versus AKR mice. Conclusions: Our data demonstrate that the previously established efficacy of VSL#3 in preventing SAMP ileitis is due to direct innate and homeostatic effects of TNF on the gut epithelium, modulation of the TJ proteins, claudin-2 and occludin, and overall improvement of intestinal permeability. © 2012 Corridoni et al

English Language Teaching Approaches: A Comparison of the Grammar-translation, Audiolingual, Communicative, and Natural Approaches

This work compares four of the most widely used teaching approaches in foreign language contexts; Grammar-Translation, Audiolingual, Communicative, and Natural Approaches. For the comparison, seven features were considered; supporting theories, creation purpose, materials and techniques used, and the roles of teachers, students, and students´ mother tongue in the teaching-learning process. A checklist was created to provide a visual representation of the characterization of the features compared in each approach. Several texts and articles were reviewed to be accurate in the characterization of the information. The results show that the characteristics of each approach were determined for the epoch in which they were proposed and promoted. Some characteristics such as the use of books overlapped all approaches compared in this work; others were unique to certain approaches, supporting theories, for instance; and, others were common in two or three approaches, as in the case of the use of conversations and the role of learners as active learners, to cite some examples

Influence of Zn-Cd Substitution: An NMR and Theoretical Study of the Complexes of 8-Hydroxyquinoline

Abstract: The 1

Inflammation mobilizes copper metabolism to promote colon tumorigenesis via an IL-17-STEAP4-XIAP axis.

Copper levels are known to be elevated in inflamed and malignant tissues. But the mechanism underlying this selective enrichment has been elusive. In this study, we report a axis by which inflammatory cytokines, such as IL-17, drive cellular copper uptake via the induction of a metalloreductase, STEAP4. IL-17-induced elevated intracellular copper level leads to the activation of an E3-ligase, XIAP, which potentiates IL-17-induced NFκB activation and suppresses the caspase 3 activity. Importantly, this IL-17-induced STEAP4-dependent cellular copper uptake is critical for colon tumor formation in a murine model of colitis-associated tumorigenesis and STEAP4 expression correlates with IL-17 level and XIAP activation in human colon cancer. In summary, this study reveals a IL-17-STEAP4-XIAP axis through which the inflammatory response induces copper uptake, promoting colon tumorigenesis