Plasmonics with two-dimensional semiconductors "beyond graphene": from basic research to technological applications

In this minireview, we explore the main features and the prospect of plasmonics with two-dimensional semiconductors. Plasmonic modes in each class of van der Waals semiconductors have their own peculiarities, along with potential technological capabilities. Plasmons of transition-metal dichalcogenides share features typical of graphene, due to their honeycomb structure, but with damping processes dominated by intraband rather than interband transitions, unlike graphene. Spin-orbit coupling strongly affects the plasmonic spectrum of buckled honeycomb lattices (silicene and germanene), while the anisotropic lattice of phosphorene determines different propagation of plasmons along the armchair and zigzag direction. We also review existing applications of plasmonics with two-dimensional materials in the fields of thermoplasmonics, biosensing, and plasma-wave Terahertz detection. Finally, we consider the capabilities of van der Waals heterostructures for innovative low-loss plasmonic devices.Comment: 8 pages, 4 figures, This is the pre-peer reviewed, authors' version of the published Nanoscale article, 2018; minor revisio

Indium selenide: An insight into electronic band structure and surface excitations

We have investigated the electronic response of single crystals of indium selenide by means of angle-resolved photoemission spectroscopy, electron energy loss spectroscopy and density functional theory. The loss spectrum of indium selenide shows the direct free exciton at similar to 1.3 eV and several other peaks, which do not exhibit dispersion with the momentum. The joint analysis of the experimental band structure and the density of states indicates that spectral features in the loss function are strictly related to single-particle transitions. These excitations cannot be considered as fully coherent plasmons and they are damped even in the optical limit, i.e. for small momenta. The comparison of the calculated symmetry-projected density of states with electron energy loss spectra enables the assignment of the spectral features to transitions between specific electronic states. Furthermore, the effects of ambient gases on the band structure and on the loss function have been probed

Leishmania isoenzyme polymorphisms in Ecuador: Relationships with geographic distribution and clinical presentation

Background: Determinants of the clinical presentation of the leishmaniases are poorly understood but Leishmania species and strain differences are important. To examine the relationship between clinical presentation, species and isoenzyme polymorphisms, 56 Leishmania isolates from distinct presentations of American tegumentary leishmaniasis (ATL) from Ecuador were analyzed. Methods: Isolates were characterized by multilocus enzyme electrophoresis for polymorphisms of 11 isoenzymes. Patients were infected in four different ecologic regions: highland and lowland jungle of the Pacific coast, Amazonian lowlands and Andean highlands. Results: Six Leishmania species constituting 21 zymodemes were identified: L. (Viannia) panamensis (21 isolates, 7 zymodemes), L. (V.) guyanensis (7 isolates, 4 zymodemes), L. (V.) braziliensis (5 isolates, 3 zymodemes), L. (Leishmania) mexicana (11 isolates, 4 zymodemes), L. (L.) amazonensis (10 isolates, 2 zymodemes) and L. (L.) major (2 isolates, 1 zymodeme). L. panamensis was the species most frequently identified in the Pacific region and was associated with several clinical variants of cutaneous disease (CL); eight cases of leishmaniasis recidiva cutis (LRC) found in the Pacific highlands were associated with 3 zymodemes of this species. Mucocutaneous leishmaniasis found only in the Amazonian focus was associated with 3 zymodemes of L. braziliensis. The papular variant of CL, Uta, found in the Andean highlands was related predominantly with a single zymodeme of L. mexicana. Conclusion: Our data show a high degree of phenotypic variation within species, and some evidence for associations between specific variants of ATL (i.e. Uta and LRC) and specific Leishmania zymodemes. This study further defines the geographic distribution of Leishmania species and clinical variants of ATL in Ecuador

Successful isolation of Leishmania infantum from Rhipicephalus sanguineus sensu lato (Acari : Ixodidae) collected from naturally infected dogs

Background: The main transmission route of Leishmania infantum is through the bites of sand flies. However, alternative mechanisms are being investigated, such as through the bites of ticks, which could have epidemiological relevance. The objective of this work was to verify the presence of Leishmania spp. In Rhipicephalus sanguineus sensu lato collected from naturally infected dogs in the Federal District of Brazil. Methods: Ticks were dissected to remove their intestines and salivary glands for DNA extraction and the subsequent amplification of the conserved region of 120 bp of kDNA and 234 bp of the hsp70 gene of Leishmania spp. The amplified kDNA products were digested with endonucleases HaeIII and BstUI and were submitted to DNA sequencing. Isolated Leishmania parasites from these ticks were analyzed by multilocus enzyme electrophoresis, and the DNA obtained from this culture was subjected to microsatellite analyses. Results: Overall, 130 specimens of R. sanguineus were collected from 27 dogs. Leishmania spp. were successfully isolated in culture from five pools of salivary glands and the intestines of ticks collected from four dogs. The amplified kDNA products from the dog blood samples and from the tick cultures, when digested by HaeIII and BstUI, revealed the presence of L. braziliensis and L. infantum. One strain was cultivated and characterized as L. infantum by enzyme electrophoresis. The amplified kDNA products from the blood of one dog showed a sequence homology with L. braziliensis; however, the amplified kDNA from the ticks collected from this dog showed a sequence homology to L. infantum. Conclusion: The results confirm that the specimens of R. sanguineus that feed on dogs naturally infected by L. infantum contain the parasite DNA in their intestines and salivary glands, and viable L. infantum can be successfully isolated from these ectoparasites

Genetic, serological and biochemical characterization of Leishmania tropica from foci in northern Palestine and discovery of zymodeme MON-307

Background Many cases of cutaneous leishmaniasis (CL) have been recorded in the Jenin District based on their clinical appearance. Here, their parasites have been characterized in depth. Methods Leishmanial parasites isolated from 12 human cases of CL from the Jenin District were cultured as promastigotes, whose DNA was extracted. The ITS1 sequence and the 7SL RNA gene were analysed as was the kinetoplast minicircle DNA (kDNA) sequence. Excreted factor (EF) serotyping and multilocus enzyme electrophoresis (MLEE) were also applied. Results This extensive characterization identified the strains as Leishmania tropica of two very distinct sub-types that parallel the two sub-groups discerned by multilocus microsatellite typing (MLMT) done previously. A high degree of congruity was displayed among the results generated by the different analytical methods that had examined various cellular components and exposed intra-specific heterogeneity among the 12 strains. Three of the ten strains subjected to MLEE constituted a new zymodeme, zymodeme MON-307, and seven belonged to the known zymodeme MON-137. Ten of the 15 enzymes in the profile of zymodeme MON-307 displayed different electrophoretic mobilities compared with the enzyme profile of the zymodeme MON-137. The closest profile to that of zymodeme MON-307 was that of the zymodeme MON-76 known from Syria. Strains of the zymodeme MON-307 were EF sub-serotype A2 and those of the zymodeme MON-137 were either A9 or A9B4. The sub-serotype B4 component appears, so far, to be unique to some strains of L. tropica of zymodeme MON-137. Strains of the zymodeme MON-137 displayed a distinctive fragment of 417 bp that was absent in those of zymodeme MON-307 when their kDNA was digested with the endonuclease RsaI. kDNA-RFLP after digestion with the endonuclease MboI facilitated a further level of differentiation that partially coincided with the geographical distribution of the human cases from which the strains came. Conclusions The Palestinian strains that were assigned to different genetic groups differed in their MLEE profiles and their EF types. A new zymodeme, zymodeme MON-307 was discovered that seems to be unique to the northern part of the Palestinian West Bank. What seemed to be a straight forward classical situation of L. tropica causing anthroponotic CL in the Jenin District might be a more complex situation, owing to the presence of two separate sub-types of L. tropica that, possibly, indicates two separate transmission cycles involving two separate types of phlebotomine sand fly vector

Complexidade e Educação Física. Para pensar a corporeidade

This work aims to bring into dialogue two areas historically placed in opposition: knowledge and body. The purpose is to enable other forms of intervention at school and in teacher education that value the different human dimensions through which knowledge is expressed, especially the one enunciated through corporeality. Based on the epistemology of complexity and immersed in studies of everyday life, the discussion moves away from the notion of subject conferred by modernity, which disregards the complexity of formation and genetic and cultural articulation in the constitution of the human being. Anchored in the work of authors who understand the human being as a ´subject-body´ or a ´mind-incorporated´ seeks to offer subsidies that promote a disorder in the impermeable conception of knowledge with which the school has been working, allowing a greater understanding of the complexity of what is proper to the human being.  El objetivo de este trabajo de investigación es poner en diálogo dos campos que históricamente han estado en oposición: el conocimiento y el cuerpo. El propósito es posibilitar otras formas de intervención en la escuela y en la formación docente que valoren las diferentes dimensiones humanas a través de las cuales se expresa el conocimiento, especialmente aquel que se enuncia a través de la corporeidad. Basada en la epistemología de la complejidad e inmersa de estudios de la vida cotidiana, la discusión se desplaza desde la noción de sujeto conferida por la modernidad, que desconsidera la complejidad de la formación y la articulación genética y cultural en la constitución del humano y, anclada en el trabajo de autores que entienden al ser humano como un ‘cuerposujeto’ o una ‘menteincorporada’, busca ofrecer subsidios que promuevan un desorden en la concepción impermeable del saber con el que ha venido trabajando la escuela, permitiendo una mayor amplitud de comprensión de la complejidad de lo que es propio del humano.Este trabalho tem como objetivo colocar em diálogo dois campos postos historicamente em oposição: conhecimento e corpo. O intuito é o de possibilitar outras formas de intervenção na escola e na formação de professores que valorizem as diferentes dimensões humanas pelas quais o conhecimento se expressa, especialmente aquela que se enuncia através da corporeidade. Fundamentada na epistemologia da complexidade e mergulhada nos estudos com os cotidianos, a discussão desloca-se da noção de sujeito conferida pela modernidade, que desconsidera a complexidade da formação e da articulação genética e cultural na constituição do humano e, com ancoragem nos trabalhos de autores que entendem o ser humano como um ‘corposujeito’ ou uma ‘menteincorporada’, busca oferecer subsídios que promovam uma desordem na concepção impermeável de conhecimento com a qual a escola vem trabalhando, permitindo maior amplitude de compreensão da complexidade do que é próprio do humano

“Que a justiça seja feita”: a dinâmica do esforço X recompensa no Caldeirão do Huck

Com as luzes ainda apagadas, cinco dançarinas se encontram no centro do palco e, ao som da música tema de Caldeirão do Huck, começam a dançar. As luzes se acendem. Ao fundo, ouve-se a voz de Luciano Huck: “Quebra tudo no Caldeirão”. O apresentador se dirige à platéia de jovens, com empolgação, fazendo a abertura de seu programa. A platéia responde com gritos, assobios, palmas. Todos dançam. As câmeras novamente se fecham nas dançarinas, que sorriem animadamente. É assim que, nas tardes de sábado, na Rede Globo, tem início o programa juvenil Caldeirão do Huck. No ar desde o ano 2000 nesta emissora, o programa, com duas horas de duração, já passou por diversas modificações; o histórico inclui atrações do tipo reality show (a exemplo do “Acorrentados”), várias modalidades de jogos interativos, além dos quadros vinculados aos personagens criados pelo programa. Apesar da remodelação constante, uma modalidade específica de atração sempre esteve presente: os jogos competitivos. Com ou sem a participação da platéia, os jogos já ofereceram diversos tipos de prêmio: brindes com a logomarca do programa, dinheiro, papéis em novela, reforma na casa, no carro, entre outras coisas