Spin-polarized Majorana zero modes in proximitized superconducting penta-silicene nanoribbons.

We theoretically propose penta-silicene nanoribbons (p-SiNRs) with induced p-wave superconductivity as a platform for the emergence of spin-polarized Majorana zero-modes (MZMs). The model explicitly considers the key ingredients of well-known Majorana hybrid nanowire setups: Rashba spin-orbit coupling, magnetic field perpendicular to the nanoribbon plane, and first nearest neighbor hopping with p-wave superconducting pairing. The energy spectrum of the system, as a function of chemical potential, reveals the existence of MZMs with a well-defined spin orientation localized at the opposite ends of both the top and bottom chains of the p-SiNR, associated with well-localized and nonoverlapping wave function profiles. Well-established experimental techniques enable the fabrication of highly ordered p-SiNRs, complemented by a thin lead film on top, responsible for inducing p-wave superconductivity through proximity effect. Moreover, the emergence of MZMs with explicit opposite spin orientations for some set of model parameters opens a new avenue for exploring quantum computing operations, which accounts for both MZMs and spin properties, as well as for new MZMs probe devices based on spin-polarized electronic transport mechanisms.

The cumulant Green's functions method for the Hubbard model.

We use the cumulant Green's functions method (CGFM) to study the single-band Hubbard model. The starting point of the method is to diagonalize a cluster ('seed') containingNcorrelated sites and employ the cumulants calculated from the cluster solution to obtain the full Green's functions for the lattice. All calculations are done directly; no variational or self-consistent process is needed. We benchmark the one-dimensional results for the gap, the double occupancy, and the ground-state energy as functions of the electronic correlation at half-filling and the occupation numbers as functions of the chemical potential obtained from the CGFM against the corresponding results of the thermodynamic Bethe ansatz and the quantum transfer matrix methods. The particle-hole symmetry of the density of states is fulfilled, and the gap, occupation numbers, and ground-state energy tend systematically to the known results as the cluster size increases. We include a straightforward application of the CGFM to simulate the singles occupation of an optical lattice experiment with lithium-6 atoms in an eight-site Fermi-Hubbard chain near half-filling. The method can be applied to any parameter space for one, two, or three-dimensional Hubbard Hamiltonians and extended to other strongly correlated models, like the Anderson Hamiltonian, thet - J, Kondo, and Coqblin-Schrieffer models.

Thermoelectric properties of topological chains coupled to a quantum dot.

Topological one-dimensional superconductors can sustain zero energy modes protected by different kinds of symmetries in their extremities. Observing these excitations in the form of Majorana fermions is one of the most intensive quests in condensed matter physics. We are interested in another class of one-dimensional topological systems in this work, namely topological insulators. Which present symmetry-protected end modes with robust properties and do not require the low temperatures necessary for topological superconductivity. We consider a device in the form of a single electron transistor coupled to the simplest kind of topological insulators, namely chains of atoms with hybridized sp orbitals. We study the thermoelectric properties of the device in the trivial, non-trivial topological phases and at the quantum topological transition of the chains. We show that the device's electrical conductance and the Wiedemann-Franz ratio at the topological transition have universal values at very low temperatures. The conductance and thermopower of the device with diatomic sp-chains, at their topological transition, give direct evidence of fractional charges in the system. The former has an anomalous low-temperature behavior, attaining a universal value that is a consequence of the double degeneracy of the system due to the presence of zero energy modes. On the other hand, the system can be tuned to exhibit high values of the thermoelectric figure of merit and the power factor at high temperatures.

Chiral magnetic chemical bonds in molecular states of impurities in Weyl semimetals.

We demonstrate that chirality of the electron scattering in Weyl semimetals leads to the formation of magnetic chemical bonds for molecular states of a pair of impurities. The effect is associated with the presence of time-reversal symmetry breaking terms in the Hamiltonian which drive a crossover from s- to p-wave scattering. The profiles of the corresponding molecular orbitals and their spin polarizations are defined by the relative orientation of the lines connecting two Weyl nodes and two impurities. The magnetic character of the molecular orbitals and their tunability open the way for using doped Weyl semimetals for spintronics and realization of qubits.

Fatty acid composition of vegetable oil blend and in vitro effects of pharmacotherapeutical skin care applications.

Vegetable oils have been used for a plethora of health benefits by their incorporation in foods, cosmetics, and pharmaceutical products, especially those intended for skin care. This study aimed to investigate the cutaneous benefits of a vegetable oil blend (VOB) formulation and its fatty acid composition. The anti-inflammatory activity was studied in macrophages of RAW 264.7 cells by investigating the release of nitric oxide (NO), superoxide anion generation (O2-), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6). ABTS cation radical scavenging capacity assay, ferric reducing antioxidant potential (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and NO free radical scavenging assays were used to evaluate the antioxidant activity. VOB was tested for its ability to stimulate fibroblast proliferation and migration using the scratch assay, and antibacterial activity by the microdilution test. The fatty acid profile of a freshly prepared VOB formulation was determined by gas chromatography before and after accelerated stability testing. Chemical composition of VOB revealed the presence of oleic acid (C18:1n-9; 63.3%), linoleic acid (C18:2n-6; 4.7%), and linolenic acid (C18:3n-6; 5.1%) as major mono- and polyunsaturated fatty acids. No changes in the organoleptic characteristics and fatty acid composition were observed after the accelerated stability test. VOB 100 µg/mL reduced the healing time by increasing the total number of cells in the wounded area by 43.0±5.1% compared to the negative control group. VOB also suppressed the pro-inflammatory TNF-α and IL-6 cytokines, and NO and O2- production in lipopolysaccharide-stimulated macrophage cells. In conclusion, the VOB formulation contributed to the improvement of current therapeutic strategies for cutaneous applications in skin care.

Fatty acid composition of vegetable oil blend and in vitro effects of pharmacotherapeutical skin care applications

Vegetable oils have been used for a plethora of health benefits by their incorporation in foods, cosmetics, and pharmaceutical products, especially those intended for skin care. This study aimed to investigate the cutaneous benefits of a vegetable oil blend (VOB) formulation and its fatty acid composition. The anti-inflammatory activity was studied in macrophages of RAW 264.7 cells by investigating the release of nitric oxide (NO), superoxide anion generation (O2-), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6). ABTS cation radical scavenging capacity assay, ferric reducing antioxidant potential (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and NO free radical scavenging assays were used to evaluate the antioxidant activity. VOB was tested for its ability to stimulate fibroblast proliferation and migration using the scratch assay, and antibacterial activity by the microdilution test. The fatty acid profile of a freshly prepared VOB formulation was determined by gas chromatography before and after accelerated stability testing. Chemical composition of VOB revealed the presence of oleic acid (C18:1n-9; 63.3%), linoleic acid (C18:2n-6; 4.7%), and linolenic acid (C18:3n-6; 5.1%) as major mono- and polyunsaturated fatty acids. No changes in the organoleptic characteristics and fatty acid composition were observed after the accelerated stability test. VOB 100 µg/mL reduced the healing time by increasing the total number of cells in the wounded area by 43.0±5.1% compared to the negative control group. VOB also suppressed the pro-inflammatory TNF-α and IL-6 cytokines, and NO and O2- production in lipopolysaccharide-stimulated macrophage cells. In conclusion, the VOB formulation contributed to the improvement of current therapeutic strategies for cutaneous applications in skin care.

Tuning of heat and charge transport by Majorana fermions.

We investigate theoretically thermal and electrical conductances for the system consisting of a quantum dot (QD) connected both to a pair of Majorana fermions residing at the edges of a Kitaev wire and two metallic leads. We demonstrate that both quantities reveal pronounced resonances, whose positions can be controlled by tuning of an asymmetry of the couplings of the QD and a pair of MFs. Similar behavior is revealed for the thermopower, Wiedemann-Franz law and dimensionless thermoelectric figure of merit. The considered geometry can thus be used as a tuner of heat and charge transport assisted by MFs.

The role of short-range magnetic correlations in the gap opening of topological Kondo insulators.

In this article we investigate the effects of short-range anti-ferromagnetic correlations on the gap opening of topological Kondo insulators. We add a Heisenberg term to the periodic Anderson model at the limit of strong correlations in order to allow a small degree of hopping of the localized electrons between neighboring sites of the lattice. This new model is adequate for studying topological Kondo insulators, whose paradigmatic material is the compound [Formula: see text]. The main finding of the article is that the short-range antiferromagnetic correlations, present in some Kondo insulators, contribute decisively to the opening of the Kondo gap in their density of states. These correlations are produced by the interaction between moments on the neighboring sites of the lattice. For simplicity, we solve the problem on a two dimensional square lattice. The starting point of the model is the [Formula: see text] ions orbitals, with [Formula: see text] multiplet in the presence of spin-orbit coupling. We present results for the Kondo and for the antiferromagnetic correlation functions. We calculate the phase diagram of the model, and as we vary the [Formula: see text] level position from the empty regime to the Kondo regime, the system develops metallic and topological Kondo insulator phases. The band structure calculated shows that the model describes a strong topological insulator.

MicroRNAs: potential therapeutic targets in diabetic complications of the cardiovascular and renal systems.

Diabetes mellitus is a serious health problem that can lead to several pathological complications in numerous organs and tissues. The most important and most prevalent organs affected by this disease are the heart and the kidneys, and these complications are the major causes of death in patients with diabetes. MicroRNAs (miRNAs), short non-coding RNAs, have been found to be functionally important in the regulation of several pathological processes, and they are emerging as an important therapeutic tool to avoid the complications of diabetes mellitus. This review summarizes the knowledge on the effects of miRNAs in diabetes. The use of miRNAs in diabetes from a clinical perspective is also discussed, focusing on their potential role to repair cardiovascular and renal complications.

Translating neurotrophic and cellular plasticity: from pathophysiology to improved therapeutics for bipolar disorder.

OBJECTIVE: Bipolar disorder (BD) likely involves, at a molecular and cellular level, dysfunctions of critical neurotrophic, cellular plasticity and resilience pathways and neuroprotective processes. Therapeutic properties of mood stabilizers are presumed to result from a restoration of the function of these altered pathways and processes through a wide range of biochemical and molecular effects. We aimed to review the altered pathways and processes implicated in BD, such as neurotrophic factors, mitogen-activated protein kinases, Bcl-2, phosphoinositol signaling, intracellular calcium and glycogen synthase kinase-3. METHODS: We undertook a literature search of recent relevant journal articles, book chapter and reviews on neurodegeneration and neuroprotection in BD. Search words entered were 'brain-derived neurotrophic factor,''Bcl-2,''mitogen-activated protein kinases,''neuroprotection,''calcium,''bipolar disorder,''mania,' and 'depression.' RESULTS: The most consistent and replicated findings in the pathophysiology of BD may be classified as follows: i) calcium dysregulation, ii) mitochondrial/endoplasmic reticulum dysfunction, iii) glial and neuronal death/atrophy and iv) loss of neurotrophic/plasticity effects in brain areas critically involved in mood regulation. In addition, the evidence supports that treatment with mood stabilizers; in particular, lithium restores these pathophysiological changes. CONCLUSION: Bipolar disorder is associated with impairments in neurotrophic, cellular plasticity and resilience pathways as well as in neuroprotective processes. The evidence supports that treatment with mood stabilizers, in particular lithium, restores these pathophysiological changes. Studies that attempt to prevent (intervene before the onset of the molecular and cellular changes), treat (minimize severity of these deficits over time), and rectify (reverse molecular and cellular deficits) are promising therapeutic strategies for developing improved treatments for bipolar disorder.

Oral mucosa as a source of Mycobacterium leprae infection and transmission, and implications of bacterial DNA detection and the immunological status.

Leprosy is an important health problem in Brazil despite extensive use of multidrug therapy. The nasal mucosa is the preferential site of entry and exit of Mycobacterium leprae, and although lesions have been found in the oral mucosa, its potential involvement in the transmission of leprosy bacilli has never been investigated. We investigated the presence of the M. leprae DNA in buccal swabs of leprosy patients (334) and household contacts (1288) through polymerase chain reaction (PCR), and correlated this with clinical and laboratorial evaluations. The overall positivity for patients and contacts was 18.26% and 6.83%, respectively. Subclinical infection among contacts was considered when PCR and anti-PGL-1 ELISA presented positive results. This study provides evidence that the oral mucosa may be a secondary site of M. leprae transmission and infection, and contacts with bacillary DNA may be actively involved in transmission. We have also shown that bacilli DNA is more frequently found in the oral mucosa of PB patients. Our findings have great epidemiological relevance and indicate an additional strategy for leprosy control programmes and dental clinics.

The atomic approach to the Anderson model for the finite U case: application to a quantum dot.

In the present work we apply the atomic approach to the single-impurity Anderson model (SIAM). A general formulation of this approach, that can be applied both to the impurity and to the lattice Anderson Hamiltonian, was developed in a previous work (Foglio et al 2009 arxiv: 0903.0139v2 [cond-mat.str-el]). The method starts from the cumulant expansion of the periodic Anderson model, employing the hybridization as a perturbation. The atomic Anderson limit is analytically solved and its sixteen eigenenergies and eigenstates are obtained. This atomic Anderson solution, which we call the AAS, has all the fundamental excitations that generate the Kondo effect, and in the atomic approach is employed as a 'seed' to generate the approximate solutions for finite U. The width of the conduction band is reduced to zero in the AAS, and we choose its position such that the Friedel sum rule is satisfied, close to the chemical potential mu. We perform a complete study of the density of states of the SIAM over the whole relevant range of parameters: the empty dot, intermediate valence, Kondo and magnetic regimes. In the Kondo regime we obtain a density of states that characterizes well the structure of the Kondo peak. To show the usefulness of the method we have calculated the conductance of a quantum dot, side-coupled to a conduction band.

Uso da oxigenoterapia hiperbárica em pacientes de um serviço de reumatologia pediátrica / Hyperbaric oxygen therapy in patients of a pediatric rheumatology service

A oxigenoterapia hiperbárica consiste na respiração de oxigênio puro sob pressão maior que uma atmosfera e vem sendo empregada no tratamento adjuvante de lesões ulceradas de várias etiologias. Foram analisados retrospectivamente os prontuários de seis pacientes atendidos no Ambulatório de Reumatologia Pediátrica do Instituto da Criança do Hospital das Clínicas da FMUSP entre 1996 e 2002, submetidos à oxigenoterapia hiperbárica. Esse procedimento foi indicado pela presença de osteomielite crônica e lesões ulceradas (por vasculite ou infecção) que não responderam ao tratamento habitual. Dois pacientes apresentaram poliarterite nodosa cutânea, dois osteomielite crônica multifocal recorrente, um esclerodermia cutânea difusa e um pioderma gangrenoso. Cinco pacientes eram do sexo feminino (idade variou de 6 a 13,2 anos). As sessões de oxigenoterapia hiperbárica foram realizadas sob pressões que variaram de 2,4 a 2,8 atmosferas absolutas, com duração de duas horas. O número mínimo de sessões foi 18 e o máximo 80. Em cinco pacientes houve completa cicatrização das lesões. A paciente com esclerodermia cutânea abandonou o tratamento após a décima oitava sessão, pois retornou a sua cidade natal, com melhora parcial das lesões cutâneas. O principal evento adverso durante as sessões foi otalgia, após as primeiras sessões, que desapareceu com diminuição da pressão dentro da câmara e da duração da sessão. Não foram observados perfuração timpânica ou outros eventos adversos. A oxigenoterapia hiperbárica foi eficaz e bem tolerada nos pacientes com doenças reumatológicas e lesões vasculíticas ulceradas ou infectadas e osteomielite crônica.

Hyperhydricity in in vitro eggplant regenerated plants: structural characteristics and involvement of BiP (Binding Protein).

The hyperhydricity in eggplant (Solanum melongena L.) plants was monitored by the induction of the ER-luminal resident protein BiP. Although tissue culture conditions may induce BiP synthesis, the accumulation of BiP in hyperhydric shoots was consistently higher than in non-hyperhydric shoots. The leaf and stem anatomy in non-hyperhydric and hyperhydric eggplant was investigated aiming to identify structural changes associated with this phenomenon. In non-hyperhydric organs there were smaller and more organized cells, besides a more differentiated vascular system when compared with its hyperhydric counterpart. Scanning electron microscopy of leaves showed that leaf surface and stomata differentiation were also affected in hyperhydric plants.

Medical students at risk of nosocomial transmission of Mycobacterium tuberculosis.

SETTING: University and teaching hospital in Rio de Janeiro, Brazil, a city with a high prevalence of tuberculosis (TB). OBJECTIVE: To determine whether medical students are at increased risk of nosocomial transmission of Mycobacterium tuberculosis relative to other university students. DESIGN: A cross-sectional study of medical and chemical engineering students in different levels of their training programmes. Information about socio-demographic characteristics, BCG vaccination history, and potential exposures to TB were obtained using a standardised questionnaire. Tuberculin skin testing (TST) was used to determine the prevalence of infection with TB. RESULTS: Medical students have an increasing prevalence of TST positivity as they advance in their training programme to increasing levels of study (4.6%, 7.8%, 16.2%, respectively, P < 0.001), but chemical engineering students do not (4.2%, 4.3%, 4.4%, respectively, P = 0.913). The risks are greatest during the years of clinical training, when medical students have increased contact with patients. CONCLUSIONS: Medical students in this setting may be at increased risk of M. tuberculosis infection, relative to chemical engineering students. A programme of routine tuberculin skin testing is needed, combined with interventions to reduce the risk of nosocomial transmission in the workplace.

Influence of the antibiotic timentin on plant regeneration of tomato (Lycopersicon esculentum Mill.) cultivars.

Cotyledon explants of tomato (Lycopersicon esculentum Mill. cvs 'Santa Clara', 'Firme' mutant, 'IPA-5' and 'IPA-6') were excised from 8- to 10-day-old in vitro-grown seedlings. Four different shoot induction media supplemented with timentin (300 mg l-1) were screened. When cotyledon explants were cultured on MS-based medium with 1.0 mg l-1 zeatin plus 0.1 mg l-1 IAA and supplemented with timentin, higher regeneration frequencies and a greater number of elongated shoots were obtained. It was observed that timentin caused an increase in the morphogenesis of in vitro cotyledon explants of tomato cultivars. In two of three cultivars tested, rooting of shoots was positively influenced, both in the presence and absence of timentin in the rooting medium, among shoots regenerated from explants derived from timentin-supplemented medium. The results confirm those of a previous investigation on the beneficial effects of this class of antibiotics on tomato regeneration and, consequently, its reliability for use in the transformation of this species.

Cyanide degradation by an Escherichia coli strain.

Chemical formation of a glucose-cyanide complex was necessary for metabolic degradation of cyanide at concentrations up to 50.0 mg/L by a strain of Escherichia coli isolated from gold extraction circuit liquids. Ammonia accumulating during the culture log phase as the sole nitrogen by-product was further utilized for bacterial growth. Washed (intact) cells, harvested at different periods of bacterial growth on cyanide, consumed oxygen in presence of cyanide. These findings suggest that metabolism of cyanide involved a dioxygenase enzyme that converted cyanide directly to ammonia, without the formation of cyanate.

A crianca hospitalizada: refexoes de equipe. / Hospitalized child: reflexions of the health team

Este trabalho foi escrito a partir das reflexoes de um grupo que se reunia semanalmente para discutir aspectos relativos a internacao de seus pacientes, sendo um primeiro esforco de sistematizacao e supondo dois momentos: o questionamento de aspectos que consideramos muito pregnantes em nossas relacoes com a crianca hospitalizada e seus familiares e o aprofundamento destas questoes a partir de uma compreensao teorica. Procuramos, assim, identificar em aspectos particulares os denominadores comuns do trabalho de uma equipe de saude, detectando vivencias e sentimentos que nao se prenderiam as especificidades desta equipe, mas que seriam quase determinados pelo lidar com a crianca hospitalizada

O impacto emocional da hospitalizacao da crianca. / Emotional impact in child hospitalization

Neste trabalho, refletimos sobre a situacao de hospitalizacao da crianca. Admitimos que esta e uma experiencia estressante, mas que pode ser amenizada pelo favorecimento de certas condicoes, como presenca de familiares, contato com outras criancas, disponibilidade afetiva da equipe, informacao etc. Analisamos problemas como recusa a medicacao ou dificuldade em permitir a realizacao de exames dolorosos e assinalamos a maior sensibilizacao da crianca com doenca cronica ou terminal.Observamos que as criancas costumam expressar suas duvidas e angustias por vias indiretas, ou mesmo por perguntas a alguem da equipe, sendo fundamental estar atento a comunicacao da crianca hospitalizada