Bott--Kitaev periodic table and index theory

We consider topological insulators and superconductors with discrete symmetries and clarify the relevant index theory behind the periodic table proposed by Kitaev. An effective Hamiltonian determines the analytical index, which can be computed by a topological index. We focus on the spatial dimensions one, two and three, and only consider the bulk theory. In two dimensions, the $\mathbb{Z}$-valued invariants are given by the first Chern number. Meanwhile, $\mathbb{Z}_2$-valued invariants can be computed by the odd topological index and its variations. The Bott-Kitaev periodic table is well-known in the physics literature, we organize the topological invariants in the framework of KR-theory.Comment: 37 page

Estimation of free water-corrected microscopic fractional anisotropy.

Water diffusion anisotropy MRI is sensitive to microstructural changes in the brain that are hallmarks of various neurological conditions. However, conventional metrics like fractional anisotropy are confounded by neuron fiber orientation dispersion, and the relatively low resolution of diffusion-weighted MRI gives rise to significant free water partial volume effects in many brain regions that are adjacent to cerebrospinal fluid. Microscopic fractional anisotropy is a recent metric that can report water diffusion anisotropy independent of neuron fiber orientation dispersion but is still susceptible to free water contamination. In this paper, we present a free water elimination (FWE) technique to estimate microscopic fractional anisotropy and other related diffusion indices by implementing a signal representation in which the MRI signal within a voxel is assumed to come from two distinct sources: a tissue compartment and a free water compartment. A two-part algorithm is proposed to rapidly fit a set of diffusion-weighted MRI volumes containing both linear- and spherical-tensor encoding acquisitions to the representation. Simulations an

Effect of osmolytes on the activity of anti-cancer enzyme L-Asparaginase II from Erwinia chrysanthemi

L-asparaginase is used for the treatment of acute lymphoblastic leukaemia (ALL); however, its formulation presents drawbacks such as a lack of stability and formation of aggregates. Osmolytes are small molecules accumulated by cells in response to environmental stresses and present a protective behaviour, favouring the equilibrium of macromolecules towards the native conformation. Therefore, osmolytes are employed as excipients in pharmaceutical protein formulations. Herein, recombinant L-ASNase II from Erwinia chrysanthemi (ErA II) was analysed with respect to the effect of osmolytes on kinetic and stability of this biopharmaceutical. The aggregation profiles were analysed trough nanotracking particle analysis and dynamic light scattering. The majority of the tested osmolytes increased ErA II specific activity and stability, being more pronounced for sucrose and sorbitol, which increased almost 70% of ErA II activity. The polyol preserved total enzyme activity for 30 days while sucrose preserved 81.1 ± 5.3% total enzyme activity over this period. Each osmolyte resulted in a specific aggregation profile and the presence of sucrose or sorbitol resulted in a lower quantity of aggregates in the range of 100–300 nm. The present findings may contribute to the improvement of adjuvants in L-ASNase formulations and the optimization of other biopharmaceutical formulations.publishe

Development and Applications of Aluminum Nitride Thin Film Technology

Aluminum nitride (AlN) thin films have aroused the interest of researchers due to their unique physicochemical properties. However, further studies on these semiconductor materials are still necessary to establish the manufacturing of high-performance devices for applications in various areas, such as telecommunications, microelectronics, and biomedicine. This chapter introduces AlN thin film technology that has made a wide range of applications possible. First, the main physicochemical properties of AlN, its wurtzite crystalline structure, and the incorporation of oxygen during the thin film deposition process are presented. Furthermore, the growth of AlN films by different techniques and their applications as a buffer layer and sensing layer are summarized. Special attention was given to the sputtering deposition process and the use of sputtered AlN films in SAW sensors

Estudo anatômico comparativo dos nervos da perna de Cebus (macaco-prego) com babuínos, chimpanzés e humanos modernos

Os estudos anatômicos comparativos entre os primatas são importantes para pesquisas associadas com a etologia, evolução, taxonomia e compreensão dos usos de ferramentas pelos hominídeos. Especificamente, o conhecimento anatômico sobre Cebus contribui para sua própria conservação e para o desenvolvimento de procedimentos cirúrgicos e tratamentos clínicos destes animais, pois são frequentemente vítimas de acidentes automobilísticos. Recentemente, estudos sobre características comportamentais de Cebus indicaram conclusões erradas sobre sua anatomia, o que pode ser atribuído aos poucos dados disponíveis sobre a anatomia desses animais na literatura especializada. Portanto, para fornecer dados anatômicos e fornecer suporte para as outras ciências relacionadas com a anatomia e também desenvolver procedimentos cirúrgicos e/ou clínicos, foram descritos os nervos das pernas de Cebus com enfoque sobre a posição, a trajetória e os músculos inervados, e comparar esses resultados com os dos humanos modernos e outros primatas. Oito espécimes adultos de macacos-prego foram usados para este estudo. O estudo anatômico comparativo dos nervos da perna de Cebus demonstrou que, em geral, a organização estrutural dos nervos é semelhante entre os quatro primatas aqui analisados (Cebus, chimpanzés, babuínos e humanos modernos), o que pode ser atribuído ao fato de que os quatro primatas terem estruturas corporais semelhantes. No entanto, a trajetória dos nervos e a inervação dos músculos em Cebus o aproximam dos babuínos.The anatomical comparative studies among the primates are important for the investigation of ethology, evolution, taxonomy, and comprehension of tools by hominoids. Especially the anatomical knowledge of Cebus contributes to conservation of the species, and to development of surgical procedures and clinical treatments of these animals, as they frequently are victims of automobile accidents. Recent anatomical studies came to a wrong conclusion regarding behavioral traits of Cebus, ascribed to few data available in previous literature. Therefore, to provide anatomical data and to support the other sciences related to anatomy, and to develop surgical and/or clinical procedures, we described the nerves of the legs of Cebus foccusing on their position and trajectory, as wll as innerved muscles, and compared these results with those of humans and other primates. Eight adult capuchin specimens were used for this study. The anatomical comparative study of the leg's nerves of Cebus demonstrated that, in general, structural organization of the nerves is similar among the four primates analyzed here (Cebus, chimpanzees, baboons and humans), which might be attributed to the fact that the all four primates have similar body structures. However, nerve trajectory and muscles innervation in Cebus was more similar to baboons

Effect of anthropic activities on aoil geochemistry in toposequences of the Rio Grande do Sul Plateau, Brazil

A gestão agrícola e ambiental eficaz depende da compreensão da variação do conteúdo total dos elementos químicos no solo. Neste trabalho (i) foram determinados os teores totais de elementos químicos em solos de duas topossequências localizadas no planalto do Rio Grande do Sul e, (ii) foi avaliada a influência dos usos antrópicos e relevo na geoquímica do solo. As amostras foram coletadas em nove pontos de amostragem e em cinco camadas de solo, num total de 45 amostras. A concentração elementar (flúor a urânio) foi determinada utilizando um espectrômetro de fluorescência de raios-X por dispersão de comprimento de onda, em pastilhas de solo previamente peneiradas em malha de 53 μm e pren- sadas. Foram estabelecidas as concentrações basais de 35 elementos químicos para os solos do planalto do Rio Grande do Sul, cujo material de origem são arenitos da formação Tupanciretã. O teor total de elementos químicos variou com a posição na encosta (ambiente de perda e deposição de material); com a intensidade da influência antrópica (adição de fertilizante, manejo do solo e drenagem da área úmida) e; com a condição hidromórfica do solo ao longo das toposse- quências.Efficient agricultural and environmental management depends upon the good understanding of the variation in the total contents in soil chemical elements. In this study (i) determine the total contents of chemical elements in soils of two toposequence located in the Rio Grande do Sul plateau and, (ii) the influence of anthropic uses and relief in soil geochem- istry. Soil samples were collected at nine sampling points and five soil layers for a total of 45 samples. The elemental concentrations (fluorine to uranium) was determined using a wavelength dispersive X-ray fluorescence spectrometer with pressed soil pellets, pre-sieved in 53 μm and pressed. The basal concentrations of 35 chemical elements were established for the soils of the Rio Grande do Sul plateau, whose material of origin are fluvial sandstones of the Tupanciretã For- mation. The chemical element levels varied according to the position in the slope (environment of loss and deposition of material); the intensity of the anthropic influence (addition of fertilizer, soil management and drainage of the wet area); and the hydromorphic condition of the soil along the topossequences

Arrangement and prevalence of branches in the external carotid artery in humans

The external carotid artery originates branches to face structures. The superior thyroid, lingual and facial arteries are originated from this vessel as artery trunks or separately. The aim of this study was to determinate the arrangement frequency of these artery branches. For this, thirty six (36) hemi-heads of adult cadavers from both genders were studied. The anatomic parts were fixed in 10% of formalin and dissected. The superior thyroid, lingual and facial arteries were analyzed in terms of their origins. The superior thyroid, lingual and facial arteries originated separately from the external or common carotid artery in 77.8% of the cases. A linguofacial trunk was observed in 19.9% of the cases and a thyrolingual trunk in 2.8%. A thyrolinguofacial trunk was not observed. In 51.2% cases the superior thyroid artery originated directly from the external carotid artery, in 45.3% from the bifurcation of the common carotid artery, and in 3.5% from the common carotid artery. Thus, the superior thyroid, lingual and facial arteries more frequently showed a separate origin from the external or common carotid artery. Among the combined artery trunks, the linguofacial trunk was most frequently observed, followed by the thyrolingual trunk. The superior thyroid artery originated more frequently from the external or common carotid artery; however, it also could emerge from the bifurcation of the common carotid artery

"Antarctic yeasts as a source of L-asparaginase: Characterization of a glutaminase-activity free L-asparaginase from psychrotolerant yeast Leucosporidium scottii L115"

"Microorganisms from extreme environments, such as the Antarctic ecosystems, have a great potential to produce enzymes with novel characteristics. Within this context, L-asparaginase (ASNase) obtained from yeast species has been poorly studied. In this study, yeasts isolated from samples collected at Admiralty Bay (King George Island, Antarctica) were tested to produce ASNase. From an initial screening of 40 strains, belonging to 13 different species, Leucosporidium scottii L115 produced an ASNase activity (LsASNase activity: 6.24 U g-1 of dry cell weight) with the lowest glutaminase activity. The LsASNase was purified 227-fold, with a specific activity of 137.01 U mg-1 at 37 ◦C, without glutaminase activity. Moreover, the maximum enzyme activity was observed at pH 7.5 and at a temperature of 55 ◦C. The enzyme is a multimer of 462 kDa, presenting a single band of 53 kDa molecular mass in reduced conditions; after PGNase F treatment, a single band of 45 kDa was observed. The enzymatic kinetic evaluation revealed an allosteric regulation of the enzyme and the kinetic parameters were determined at 37 ◦C, pH 7.0 as substrate affinity constant, K0.5 = 233 μM, kcat = 54.7 s − 1 and Hill coefficient, nH = 1.52, demonstrating positive cooperativity by the enzyme and the substrate. This is the first study to report L. scottii as a source of glutaminase-activity free L-asparaginase, an acute lymphoblastic leukemia drug feature suitable for the treatment of asparagine synthetase negative cancer cells.

Visual mismatch negativity to masked stimuli presented at very brief presentation rates

Mismatch Negativity (MMN) has been characterised as a ‘pre-attentive’ component of an event-related potential (ERP) that is related to discrimination and error prediction processes. The aim of the current experiment was to establish whether visual MMN could be recorded to briefly presented, backward and forward masked visual stimuli, given both below and above levels of subjective experience. Evidence of visual MMN elicitation in the absence of the ability to consciously report stimuli would provide strong evidence for the automaticity of the visual MMN mechanism. Using an oddball paradigm, two stimuli that differed in orientation from each other, an + and an x were presented on a computer screen. Electroencephalogram (EEG) was recorded from nine participants (six females), mean age 21.4 years. Results showed that for stimuli that were effectively masked at 7ms presentation, there was little variation in the ERPs evoked to standard and deviant stimuli or in the subtraction waveform employed to delineate the visual MMN. At 14 ms stimulus presentation, when participants were able to report stimulus presence, an enhanced negativity at around 175 ms and 305 ms was observed to the deviant and was evident in the subtraction waveform. Although some of the difference observed in the ERPs can be attributed to stimulus characteristics, the use of a ‘lonely’ deviant protocol revealed attenuated visual MMN components at 14 ms stimulus presentation. Overall, results suggest that some degree of conscious attention is required before visual MMN components emerge, suggesting visual MMN is not an entirely pre-attentive process

Peripheral electrical stimulation in Alzheimer's Disease: A randomized controlled trial on cognition and behavior

In a number of studies, peripheral electrical nerve stimulation has been applied to Alzheimer's disease (AD) patients who lived in a nursing home. Improvements were observed in memory, verbal fluency, affective behavior, activities of daily living and on the rest-activity rhythm and pupillary light reflex. The aim of the present, randomized, placebo-controlled, parallel-group clinical trial was to examine the effects of electrical stimulation on cognition and behavior in AD patients who still live at home. Repeated measures analyses of variance revealed no effects of the intervention in the verum group (n = 32) compared with the placebo group (n = 30) on any of the cognitive and behavioral outcome measures. However, the majority of the patients and the caregivers evaluated the treatment procedure positively, and applying the daily treatment at home caused minimal burden. The lack of treatment effects calls for reconsideration of electrical stimulation as a symptomatic treatment in A