A partir de 280 isolados fúngicos de cana-de-açúcar, 18 cepas foram avaliadas quanto á presença de genes da policetídeo sintase por meio da técnica do PCR. Estes fungos foram identificados taxonomicamente por uma abordagem polifásica, classificando-os dentro de quatro ordens e nove gêneros. A avaliação da atividade biológica demonstrou a presença de metabolitos com propriedades antibióticas quando enfrentados a micro-organismos patogênicos. Segundo a análise de correspondência múltipla, esta atividade poderia estar associada com a local de isolamento dos fungos. Foram detectadas 36 seqüências similares a genes PKS a partir de 17 destes fungos. A análise filogenética do domínio KS, conduzida pelo método de neighbor-joining, indicou que 16 seqüências se acomodaram dentro do grupo monofilético dos PKS envolvidos na produção de policetídeos não reduzidos e as outras 10 seqüências se acomodaram dentro do grupo monofilético dos PKS envolvidos na produção de policetídeos reduzidos. A análise do domínio CMT também apontou que as seqüências podiam se acomodaram em grupos de PKS dependendo do grau de redução do policetídeo, todas as seqüências CMT se relacionaram com PKS envolvidos na produção de policetídeos reduzidos. As análises dos modelos estruturais também demonstraram que as seqüências estavam altamente relacionadas com estruturas protéicas da família das enzimas de condensação, destacando a presença de uma hélice característica que carrega o resíduo de cisteína, responsável pela atividade de condensação. Extratos orgânicos obtidos de cultivos dos fungos foram avaliados parar detectar a presença de compostos tipo lovastatina. Por meio de cromatografia CCDS, detectaram-se bandas de 10 extratos com o mesmo deslocamento que a lovastatina padrão, mas apenas 6 destas foram confirmados por CLAE. O isolado A. flavus CBMAI 1023, foi selecionado para a realização de experimentos de produção a maior escala onde foi possível isolar e caracterizar um novo policetídeo. / From a group of 280 sugarcane-derived fungi 18 strains were assessed for the presence of polyketide synthase genes by PCR approaches. These fungi were identified taxonomically by a polyphasic approach classifying into four orders and nine genres. Biological activity tests showed the presence of antibiotic metabolites against pathogenic microorganisms and the relationship of this activity might be linked with the fungal isolate location by multiple correspondence analyses. 36 sequences similar to PKS genes fragments were detected from 17 of these fungi. A neighbor-joining phylogenetic analysis of the KS domain showed that 16 sequences fit on the monophyletic group of PKS evolved with production of non reduced polyketides, and the other 10 sequences fit on the monophyletic group of PKS evolved with the production of reduced polyketides. CMT domain analysis also pointed that the sequences fit with groups of PKS depending on polyketide reduction grade, all ten related to PKS evolved with the synthesis of reduced polyketides. Protein structural analysis also pointed out that these sequences are closely related with proteins from condensing enzyme family, highlighting the presence of a characteristic helix elbow that bears the cysteine residue responsible for the condensation activity. The fungi were also tested for their capacity of producing lovastatin compounds where chromatographic TLC detected bands from 10 extracts with the same dislocation compared to a lovastatin, but only 6 were confirmed by HPLC. The A. flavus CBMAI (1023) were selected for upscale production experiments, from where it was possible isolate and characterize a new polyketide compound.

No description available.

The thesis is devoted to some aspects of the solid-state electronic transport in the so-called viscous or hydrodynamic regime. Hydrodynamic regime in this context means that due to the large carrier density and non-negligible carrier-carrier interactions, the transport properties follow from collective, rather than single-particle phenomena. To capture the dynamics of such a system one may use description based on the conserved quantities, i.e. momentum, energy or charge. If the interactions between the constituents of the system are strong enough, such a description is provided by the hydrodynamic equations which for conserved momentum and energy are the Navier-Stokes equations or their relativistic counterparts. This thesis focuses on such a situation: when the equations governing transport properties follow from conservation of the momentum or, at most, can be treated as a modification of such equations due to weak momentum relaxation. Presented here are two lines of investigation. The first one focuses on the mesoscopic effects, i.e. on the dependence of the outcome of the transport measurements on the physical parameters of the sample such as size and shape. Here also the effects of the weak momentum relaxation are studied. In the second one, the issue of parity and time reversal symmetry breaking, occurring in a 2 dimensional system due to the presence of an external magnetic field, is investigated. An effective model of a strongly coupled quantum system is introduced and used to compute the odd (Hall) viscosity -- a transport coefficient allowed once the discrete symmetries are broken -- as a function of magnetic field, temperature and chemical potential. The first part of results concerns the behaviour of the electronic fluid in a typical AC measurement -- modeled by an elongated channel in which the fluid is subject to a periodically time dependent electric potential. Assuming standard, no-slip boundary conditions, the spatial distribution of the current density is found to be much different to the one known for Ohmic conduction. For small frequency the current distribution has a parabolic profile across the channel, while for high frequency the current in the bulk of the channel becomes flat (position-independent), while two maxima terminating a so-called boundary layer develop. In these boundary layers large gradients of current can be found, contributing to high local entropy production due to the viscous force. Despite this differences in the local current density profile, when the global conductance is measured as a function of the frequency, the result much resembles the well known Drude curve, with a distinct maximum visible in the imaginary part of the AC conductance. There is, however, a global signature of the boundary layer formation -- the scaling of the conductance with the channel width, that changes from quadratic (for parabolic flow) to asymptotically constant (for a flow with boundary layers). Moreover, in the hydrodynamic regime, the position of the Drude peak is not only determined by microscopic parameter but again by a combination of microscopic (viscosity) and mesoscopic (width) parameters. Since the Drude peak occurs for experimentally feasible values of parameters, the mentioned mesoscopic dependence may be used to measure the value of viscosity coefficient. The results discussed above are obtained assuming, as is traditional for hydrodynamics on everyday length-scales, a no-slip boundary condition which forces the fluid to be immobile at the boundary. This boundary condition was also assumed in most of the previous works on the electronic hydrodynamics. However, this is not the only possibility. There exists a one-parameter family of consistent boundary conditions involving velocity and its derivative on the boundary, parametrized by a coefficient called the slip length. Recent theoretical and experimental publications suggest that it may be dependent on the state parameters of the system (i.e temperature, chemical potential) and its value may be relatively large for some experimental situations. One of the consequences of the slip length being large is that hydrodynamic effects are obscured in the simple AC set-up discussed before. In this work it is shown that by an appropriate micro-structuring of the boundary, the effects of slip can be suppressed. Once the array of defects is introduced on the edges of the sample, the no-slip behavior is restored for all the values of the microscopic slip length. Furthermore, the interplay between the microscopic slip length and the sample geometry is investigated and used to propose a simple device for measuring the dependence of the microscopic slip length on the state parameters such as the temperature or the chemical potential. The final part of this thesis is devoted to a different aspect of the hydrodynamic transport -- a computation of the value of hydrodynamic transport coefficients using a microscopic theory. The physical situation of interest is one in which time reversal and parity invariance of a 2-dimensional system are broken, due to the presence of an external magnetic field. In such a situation an unusual class of transport coefficients is allowed in the hydrodynamic description, so-called odd coefficients. The term comes from the fact that they encode response that is transverse to the applied perturbation. These odd coefficients for 2 dimensions were previously studied mostly at weak coupling, i.e. using descriptions based on quasi-particles. This work, however, presents the way of calculating them for strongly coupled model system. To achieve this a high-energy-physics-inspired framework of holographic duality (AdS/CFT) is used. In that approach, an effective model involving magnetically-sourced parity-breaking interactions is constructed for the system at finite temperature and chemical potential. Performing a linear response analysis around the thermal states in that model allows one to read off the transport coefficients, especially the odd (Hall) viscosity coefficient that is of central interest in this study. The mentioned Hall viscosity is found to be non-zero whenever the magnetic field is present, even for zero chemical potential. This is unusual, as odd viscosity is expected to only be non-zero for non-zero charge density states. The mechanism responsible for the presence of Hall viscosity in the discussed case turns out to be the following: charge density in the model is induced by either the chemical potential or the magnetic field, i.e. for non-zero magnetic field even at zero chemical potential some density of charge is present. This charge contributes to the Hall viscosity in the usual way. The odd viscosity coefficient is found to have different scaling behaviors for weak and strong magnetic field. Interestingly, it turns out that the computations of the Hall (and shear) viscosities are relatively straightforward and analytically tractable in the proposed model. This means that the results could be generalized to the zero-temperature case, which however is yet to be done. It also suggests that the model may capture some universal mechanisms of generating the odd viscosity due to the presence of the magnetic field. That intuition is backed by the fact that some of the effective models of quantum Hall states also predict similar mechanism in which charge density is induced by the presence of the magnetic field. Despite these similarities, further studies are needed to establish a solid connection between these systems. In particular, in the model under consideration no mechanism of quantization of the Hall viscosity is found, while the mentioned models of quantum Hall states predict quantization of that transport coefficient.

No description available.

English speakers use the concept of "darkness" in a number of metaphors to portray a wide variety of experiences from evil to fear to ignorance. These metaphorical connections or entailments are so natural that we can see an image of a dark-clad person in a film or book and usually be correct in assuming that they are at best questionably moral and at worst a villain. The Old Testament (OT) also employs dark images and dark imagery to various effects. From Job's description of the underworld in Job 3 to Isaiah 's description of the coming light that will dispel the darkness in Isa 8- 9, to the dark paths the wicked trod in Eccl 2:14, the OT uses a number of metaphors of darkness. For most of these examples, it would be easy to assume that the ancient Hebrew writers of the OT were working with the same concepts of darkness that we do today and thus interpret these passages along the same lines as our own modem English metaphors. But such assumptions can and have led to a number of misunderstandings and conflicting interpretations of passages that employ dark images. These miscommunications are most apparent in passages where God's presence is indicated by darkness like at the Sinai and Temple theophanies (Exod 20:19-20 and 1 Kgs 8:12, respectively) as well as later poetry about God (Ps 97:2). By combining the theoretical framework of Cognitive Metaphor Theory (CMT), and the methodology of Conceptual Blending (CB), this study will work toward a clearer understanding of how the writers of the OT understood darkness and how that shaped their use of it in their images and imagery of death, captivity, the unknowable, and God. It will be shown that the ancient Hebrew conception and use of darkness centres around three key recurring metaphors - Death is Darkness, Captivity is Darkness, and the Unknown is Darkness - while the metaphor Evil is Darkness is foreign to the OT. These findings serve to provide greater clarity in interpreting those OT passages that portray God as having a penchant for darkness.

Spinal muscular atrophy (SMA) and Charcot-Marie-Tooth disease type 2D (CMT2D)/distal SMA type V (dSMAV) are two incurable neuromuscular disorders that predominantly manifest during childhood and adolescence. Both conditions are caused by mutations in widely and constitutively expressed genes that encode proteins with essential housekeeping functions, yet display specific lower motor neuron pathology. SMA results from recessive inactivating mutations in the survival motor neuron 1 (SMN1) gene, while CMT2D/dSMAV manifests due to dominant point mutations in the glycyl-tRNA synthetase (GlyRS) gene, GARS. Using a number of different model systems, ranging from Caenorhabditis elegans to the mouse, this thesis aimed to identify potential novel therapeutic compounds for SMA, and to increase our understanding of the mechanisms underlying both diseases. I characterised a novel C. elegans allele, which possesses a point mutation in the worm SMN1 orthologue, smn-1, and showed its potential for large-scale screening by highlighting 4-aminopyridine in a screen for compounds able to improve the mutant motility defect. Previously, the gene encoding three isoforms of chondrolectin (Chodl) was shown to be alternatively spliced in the spinal cord of SMA mice before disease onset. I performed functional analyses of the three isoforms in neuronal cells with experimentally reduced Smn levels, and determined that the dysregulation of Chodl likely reflects a combination of compensatory mechanism and contributor to pathology, rather than mis-splicing. Finally, working with two Gars mutant mice and a new Drosophila model, I have implicated semaphorin-plexin pathways and axonal guidance in the GlyRS toxic gain-of-function disease mechanism of CMT2D/dSMAV.

Aim: The aim of this thesis "Examination of vegetative system in hereditary neuropathy" is to consider the level of physical fitness, physical actvity level and quality of autonomic function in patients with hereditary neuropathy Charcot Marie Tooth and an assessment of interactions of these parameters, especially with regard to possible influence by the presence of autonomic neuropathy and with regard to neurological symptoms. Background: Although vegetative neuropathy was mentioned in the first publication about CMT, it is not widely discussed topic as part of it. Methods: Seventeen probands underwent spiroergometry, heart rate variability test, six minute walk test, rating by the CMT Neuropathy Score and Overall neuropathy disability scale and completing the IPAQ questionnaire. Results: We found symptoms of autonomic neuropathy in group of patients with CMT, especially high-frequency part of heart rate variability spectrum has a particularly significant decrease. Patients with autonomic neuropathy have shown a low fitness and functional capacity, tendency to obesity and hypertension. The observed correlation of autonomic neuropathy and neurological impairment was very weak. Conclusions: We find a neuropathy of the autonomic nervous system in patiens with hereditary motor and sensitive neuropathy...

No description available.

No description available.

<p>Entanglement entropy (EE) is a quantum information theoretic measure that quantifies the correlations between a region and its surroundings. We study this quantity in the following two setups : </p> <ul> <li>We look at the dynamics of a free minimally coupled, massless scalar field in a deSitter expansion, where the expansion stops after some time (i.e. we quench the expansion) and transitions to flat spacetime. We study the evolution of entanglement entropy (EE) and the Rényi entropy of a spatial region during the expansion and, more interestingly, after the expansion stops, calculating its time evolution numerically. The EE increases during the expansion but the growth is much more rapid after the expansion ends, finally saturating at late times, with saturation values obeying a volume law. The final state of the subregion is a partially thermalized state, reminiscent of a Gibbs ensemble. We comment on application of our results to the question of when and how cosmological perturbations decohere.</li> <li>We study the EE in a theory that is holographically dual to a BTZ black hole geometry in the presence of a scalar field, using the Ryu-Takayangi (RT) formula. Gaberdiel and Gopakumar had conjectured that the theory of N free fermions in 1+1 dimensions, for large N, is dual to a higher spin gravity theory with two scalar fields in 2+1 dimensions. So, we choose our boundary theory to be the theory of N free Dirac fermions with a uniformly winding mass, m e^iqx, in two spacetime dimensions (which describes for instance a superconducting current in an N-channel wire). However, to O(m²), thermodynamic quantities can be computed using Einstein gravity. We aim to check if the same holds true for entanglement entropy (EE). Doing calculations on both sides of the duality, we find that general relativity does indeed correctly account for EE of single intervals to O(m²).</li> </ul>