57 resultados para Mecanismos de indução
em Universidade Federal do Rio Grande do Norte(UFRN)
Resumo:
This research aimed at relating coordination and control forms to organizational performance. The multicase study was applied in two public high schools: Centro Federal de Educação Tecnológica do Rio Grande do Norte and Floriano Cavalcanti. In order to accomplish these objectives, it was developed a qualitative analysis and considered coordination and control forms of several authors. Also was considered Sander´s (1984) model of organizational performance. The mentioned model considers two criteria to analyze organizational performance: one instrumental (efficiency and efficacy) and other substantive (effectiveness e relevance). The research attempts to show the importance of balancing these criteria in a way that effectiveness and relevance becomes more important at schools. It was proven that the use of bureaucratic coordination forms has the power to influence the evaluation on the instrumental technique. At the same time, it was observed that the use of mechanisms based on the autonomy of the school is related to efficiency and efficacy. The object of this research can be considered successful
Resumo:
Cancer is a term used to represent a set of more than 100 diseases, including malignant tumors from different locations. The malignancies are the second leading cause of death in the population, representing approximately 17% of deaths of known cause. Strategies that induce differentiation have had limited success in the treatment of established cancers. In this work, a lectin purified from the marine sponge Cinachyrella apion (CaL) was evaluated due to its hemolytic, cytotoxic and antiproliferative properties, besides the ability to induce cell death via apoptosis in tumor cells. The antiproliferative activity of CaL was tested against cell lines, with the highest inhibition of tumor growth for HeLa, reducing cell growth at a dose dependent manner, with a concentration of 10 μg/mL. The hemolytic activity and toxicity against peripheral blood cells were tested using the concentration of IC50 for both trials and twice the IC50 for analysis in flow cytometry, indicating that CaL is not toxic to these cells. To assess the mechanism of cell death caused by CaL in HeLa cells, we performed flow cytometry and western blotting. The results showed the lectin probably induces cell death by apoptosis activation by pro-apoptotic protein Bax, promoting mitochondrial membrane permeabilization, cell cycle arrest in S phase, with accumulation of cells of approximately 57% in this phase, and acting as both dependent and/or independent of caspases pathway. These results suggest that CaL has the potential to be used as drug treatment against cancer.
Resumo:
The plants are often exposed to variations in environmental conditions that may trigger metabolic disturbances leading to a consequent loss in productivity of crops. These stressful conditions usually induce an accumulation of reactive oxygen species (ROS) in the cell, a condition known how oxidative stress. Among these species, hydrogen peroxide (H2O2) is an important molecule involved in numerous signaling mechanisms. The present study aimed to understand the relationship between the different enzymatic mechanisms of elimination of H2O2 by catalase (CAT) and ascorbate peroxidase (APX) in leaf tissues of seedlings of the species Vigna unguiculata L. Walp, under conditions of oxidative stress induced by application of CAT inhibitor, 3-amino-1,2,4-triazole (3-AT), and H2O2 itself on the roots. Three experiments were conducted. The first experiment was performed applying the compound 3-AT (5 mM) during the time (hours). In the second experiment, seedlings were exposed to different concentrations of H2O2 (2.5, 5.0, 7.5, 10 mM) for 48 h. The third strategy included the pre-treatment with H2O2 (2.5 mM) for 24 h, followed by subsequent treatment with the inhibitor 3-AT and recovery control condition. Treatment with 3-AT causes a strong inhibition of CAT activity in leaf tissues accompanied by an increase of activity of APX. However a decrease in oxidative damage to lipids is not observed as indicated by TBARS. It was observed that activity of APX is directly linked to the content of peroxide. Inductions in the activities of CAT and APX were observed mainly in the seedlings treated with 2.5 mM H2O2. This can be associated with a decrease in oxidative damage to lipids. In contrast, one same tendency was not observed in treatments with higher concentrations of this ROS. These results suggest that the concentration of 2.5 mM H2O2 can induce responses antioxidants later in seedling cowpea. This concentration when applied as pre-treatment for 24 h promoted an induction systems removers CAT and APX, both in activity and in terms of gene expression. However this increment was not observed in the recovered plants and the plants subsequently subjected to 3-AT. Additionally, the pretreatment was not sufficient to attenuate the inhibition of CAT activity and oxidative damage to lipids caused by the subsequent application of this inhibitor. The results showed that the application of 3-AT and H2O2 in the root systems of seedlings of cowpea promote changes in the parameters analyzed in leaf tissues that indicate a direct response to the presence of these factors or systemic signaling mecanisms. H2O2 appears to activate the responses of two antioxidant systems in this study thar does not promote greater protection in case of additional treatment with 3-AT. This demonstrates the importance of the CAT system. In this work, complete results indicate that there is a difference between the signaling and the effects caused by exposure to H2O2 and by treatment with 3-AT
Resumo:
The sequencing of the genome of Chromobacterium violaceum identified one single circular chromosome of 4.8 Mb, in which approximately 40% of the founded ORFs are classified as hypothetical conserved or hypothetical. Some genic regions of biotechnological and biological interest had been characterized, e. g., environmental detoxification and DNA repair genes, respectively. Given this fact, the aim of this work was to identify genes of C. violaceum related to stress response, as the ones involved with mechanisms of DNA repair and/or genomic integrity maintenance. For this, a genomic library of C. violaceum was built in Escherichia coli strain DH10B (RecA-), in which clones were tested to UVC resistance, resulting in five candidates clones. In the PLH6A clone were identified four ORFs (CV_3721 to 3724). Two ORFs, CV_3722 and CV_3724, were subcloned and a synergic complementation activity was observed. The occurrence of an operon was confirmed using cDNA from C. violaceum in a RT-PCR assay. Further, it was observed the induction of the operon after the treatment with UVC. Thus, this operon was related to the stress response in C. violaceum. The mutagenesis assay with rifampicin after the treatment with UVC light showed high frequency of mutagenicity for the ORF CV_3722 (Pol III δ subunit). In this way, we propose that the C. violaceum δ subunit can act in DH10B in the translesion synthesis using Pol IV in a RecA independent-manner pathway. In growth curve assays other four clones (PLE1G, PLE7B, PLE10B and PLE12H) were able to complement the function at the dose 5 J/m2 and in mutagenicity assays PLE7B, PLE10B and PLE12H showed frequencies of mutation with significant differences upon the control (DH10B), demonstrating that in some way they are involved with the stress response in C. violaceum. These clones appear to be interrelated, probably regulated by a messenger molecule (eg., nucleotide c-di-GMP) and/or global regulatory molecule (eg., σS subunit of RNA polymerase).The results obtained contribute for a better genetic knowledge of this specie and its response mechanisms to environmental stress.
Resumo:
Worldwide, families Carangidae and Rachycentridae represent one of the groups most important commercial fish, used for food, and great potential for marine aquaculture. However, the genetic bases that can underpin the future cultivation of these species, cytogenetic between these aspects are very weak. The chromosomal patterns have provided basic data for the exploration of biotechnological processes aimed at handling chromosomal genetic improvement, such as induction of polyploidy, androgenesis and ginogenesis, as well as obtaining monosex stocks and interspecific hybridizations. This paper presents a comprehensive cytogenetic survey in 10 species, seven of the family Carangidae and the monotypic family Rachycentridae. Classical cytogenetic analysis and in situ mapping of multigene sequences were employed, and additionally for the genus Selene and morphotypes of Caranx lugubris, comparisons were made using geometric morphometrics. In general, conservative species exhibit a marked chromosome number (2n=48). Although present in large part, different karyotypic form, retain many characteristics typical of chromosomal Order Perciformes, the high number of elements monobrachyal, Ag-NORs/18S rDNA sites and heterochromatin simply reduced, preferably centromeric. The main mechanisms involved in karyotypic diversification are the pericentric inversions, with secondary action of centric fusions. In addition to physical mapping and chromosome detail for the species are presented and discussed patterns of intra-and interspecific diversity, cytotaxonomic markers. This data set provides a better understanding of these patterns caryoevolutyonary groups and conditions for the development of protocols based on Biotechnology for chromosomal manipulation Atlantic these species
Resumo:
Despite advances in antibiotic therapy, bacterial meningitis (BM) remains with high mortality and morbidity rates in worldwide. One important mechanism associated to sequels during disease is the intense inflammatory response which promotes an oxidative burst and release of reactive oxygen species, consequently leading to cell death. Activation of DNA repair enzymes during oxidative stress has been demonstrated in several neurological disorders. APE1/Ref-1 is a multifunctional protein involved in DNA repair and plays a redox function on transcription factors such as NFkB and AP-1.The aim of this study was assess the role of APE1/Ref-1 on inflammatory response and the possibility of its modulation to reduce the sequels of the disease. Firstly it was performed an assay to measure cytokine in cerebrospinal fluid of patients with BM due to Streptococcus pneumoniae and Neisseriae meningitides. Further, a cellular model of inflammation was used to observe the effect of the inhibition of the endonuclease and redox activity of APE1/Ref-1 on cytokine levels. Additionally, APE1/Ref-1 expression in cortex and hippocampus of rat with MB after vitamin B6 treatment was evaluated. Altogether, results showed a similar profile of cytokines in the cerebrospinal fluid of patients from both pathogens, although IFNy showed higher expression in patients with BM caused by S. pneumoniae. On the other hand, inhibitors of APE1/Ref-1 reduced cytokine levels, mainly TNF-α. Reduction of oxidative stress markers was also observed after introduction of inhibitors in the LPS-stimulated cell. In the animal model, BM increased the expression of the protein APE1/Ref-1, while vitamin B6 promoted reduction. Thereby, this data rise important factors to be considered in pathogenesis of BM, e.g., IFNy can be used as prognostic factor during corticosteroid therapy, APE1/Ref-1 can be an important target to modulate the level of inflammation and VIII oxidative stress, and vitamin B6 seems modulates several proteins related to cell death. So, this study highlights a new understanding on the role of APE1/Ref-1 on the inflammation and the oxidative stress during inflammation condition
Resumo:
The main objective of this study is to apply recently developed methods of physical-statistic to time series analysis, particularly in electrical induction s profiles of oil wells data, to study the petrophysical similarity of those wells in a spatial distribution. For this, we used the DFA method in order to know if we can or not use this technique to characterize spatially the fields. After obtain the DFA values for all wells, we applied clustering analysis. To do these tests we used the non-hierarchical method called K-means. Usually based on the Euclidean distance, the K-means consists in dividing the elements of a data matrix N in k groups, so that the similarities among elements belonging to different groups are the smallest possible. In order to test if a dataset generated by the K-means method or randomly generated datasets form spatial patterns, we created the parameter Ω (index of neighborhood). High values of Ω reveals more aggregated data and low values of Ω show scattered data or data without spatial correlation. Thus we concluded that data from the DFA of 54 wells are grouped and can be used to characterize spatial fields. Applying contour level technique we confirm the results obtained by the K-means, confirming that DFA is effective to perform spatial analysis
Resumo:
Discrepancies between classical model predictions and experimental data for deep bed filtration have been reported by various authors. In order to understand these discrepancies, an analytic continuum model for deep bed filtration is proposed. In this model, a filter coefficient is attributed to each distinct retention mechanism (straining, diffusion, gravity interception, etc.). It was shown that these coefficients generally cannot be merged into an effective filter coefficient, as considered in the classical model. Furthermore, the derived analytic solutions for the proposed model were applied for fitting experimental data, and a very good agreement between experimental data and proposed model predictions were obtained. Comparison of the obtained results with empirical correlations allowed identifying the dominant retention mechanisms. In addition, it was shown that the larger the ratio of particle to pore sizes, the more intensive the straining mechanism and the larger the discrepancies between experimental data and classical model predictions. The classical model and proposed model were compared via statistical analysis. The obtained p values allow concluding that the proposed model should be preferred especially when straining plays an important role. In addition, deep bed filtration with finite retention capacity was studied. This work also involves the study of filtration of particles through porous media with a finite capacity of filtration. It was observed, in this case, that is necessary to consider changes in the boundary conditions through time evolution. It was obtained a solution for such a model using different functions of filtration coefficients. Besides that, it was shown how to build a solution for any filtration coefficient. It was seen that, even considering the same filtration coefficient, the classic model and the one here propposed, show different predictions for the concentration of particles retained in the porous media and for the suspended particles at the exit of the media
Resumo:
Reactive oxygen species (ROS) are continuously generated and can be derived from cellular metabolism or induced by exogenous factors, in addition, have the capacity to damage molecules like DNA and proteins. BER is considered the main route of DNA damage oxidative repair, however, several studies have demonstrated the importance of the proteins participation of other ways to correct these injuries. NER enzymes deficiency, such as CSB and XPC, acting in the damage recognition step in the two subways this system influences the effectiveness of oxidative damage repair. However, the mechanisms by which cells deficient in these enzymes respond to oxidative stress and its consequences still need to be better understood. Thus, the aim of this study was to perform a proteomic analysis of cell lines proficient and deficient in NER, exposed to oxidative stress, in order to identify proteins involved, directly or not, in response to oxidative stress and DNA repair. For this, three strains of human fibroblasts, MRC5-SV, CS1AN (CSBdeficient) and XP4PA (XPC-deficient) were treated with photosensitized riboflavin and then carried out the differentially expressed proteins identification by mass spectrometry. From the results, it was observed in MRC5-SV increase expression in most of the proteins involved in cellular defense, an expected response to a normal cell line subjected to stress. CS1AN showed a response disjointed, it is not possible to establish many interactions between the proteins identified, may be one explanation for their sensitivity to treatment with riboflavin and other oxidants and increased cell death probably by induction of pro-apoptotic pathways. Already XP4PA showed higher expression of apoptosis-blocking proteins, as there was inhibition or reduced expression of others involved with the activation of this process, suggesting the activation of an anti-apoptotic mechanism in this lineage, which may help explain the high susceptibility to develop cancers in XPC individuals. These results also contribute to elucidate action mechanisms of NER in oxidative damage and the understanding of important routes in the oxidative stress correlation, repair and malignant tumors formation
Resumo:
This research aims to understand the social representations Teaching Work in groups of undergraduate students of Physics and Chemistry of the Federal University of Rio Grande do Norte. For this, the proposal was based on the three theoretical and methodological consensus Carvalho (2012) in the explanation of socio-genetic mechanisms constituents of dynamic consensus that has functionality to your organization. It Was used to achieve this goal, the theoretical-epistemological Serge Moscovici (1978, 2003), Jodelet (2011), Wagner (1998,( 2011) and Carvalho (2012). The corpus analyzed results from a qualitative and quantitative research, developed in three stages. The first two (2) questionnaires to fifty (50) of each undergraduate course, a questionnaire and another profile for collection of free associations concerning motes inductors "Give Lesson," "Student" and "Teacher". The second step in the procedure Multiple Classifications, Roazzi (1995), aimed for another thirty (30) undergraduate students for each course, as well as Document Analysis of Educational Projects Curriculum courses in Physics and Chemistry. The data analysis of the first stage focused on descriptive statistics and frequency and average order of the words associated with motes inductors. The results from the Multiple Classification Procedure submitted to multidimensional analysis (MSA multidimensional scalogram analysis) and SSA (Similarity Structure Analysis), were interpreted by the theoretical and methodological proposal of the three consensus, supported by analysis of the rhetorical nature of justifications classifications and categorizations of words, boosted in times of application of Procedure Multiple Classification. The data revealed that the groups surveyed were the same Social Representation with specific dynamic consensual. Thinking Teaching Work for these groups it is considered in three dimensions: the BE-DO-HAVE of teaching. In the group of Physics consensus was clear semantic, which expressed a dynamic in which the interpretations of "Teaching Work" peacefully coexist on perceptions of two concepts: An identity around the "BE" "Teacher" or "BE" "Educator" and the other, how they think about professional development. The type of group consensus Chemistry pointed to a consensual logic hierarchical order in which the gradual between the elements of BE-DO-HAVE attested conflicts and disagreements about the perceptual object "Teaching Work", around what value most, whether they are the attributes of personal or professional-technical dimension of teaching, in the course of professional development. The thesis to explain the mechanisms of socio-genetic Representation Social Teaching Work by theoretical and methodological proposal was confirmed
Resumo:
This study board the FUNDEF social control council implementation in Parnamirim/RN city, concerning their representatives participation in the accompaniment (decision power) in resort, in front of governmental politics of decentralization, unleashed in 90´s, seen in decentralization process needs the society participation in decisions of educative institutions and represent an efficient way of solve the problems difficult the educational management actions. For this, the council creation of Brazil manager configure, since the 80´s, detaching, and the single characterizing, in actual context. The objective is raise pertinent questions of thematic of representatives members participation of collegiate organs, evidencing the decision power of these, in public resource control. The theory-methodological referential the literature treat the participation and power decision of FUNDEF social control decision, such as politics directrix that rules this council. It utilizes as proceeding of collecting data the semi-structured interview and analyze of meeting register to understand the empirics of council implantation in this city, in view of that the electoral process configured in 2003, showed as a innovation, because the counselor is indicated by the local public power representatives (in this case the education municipal secretary). The research result show the representatives have difficult, to accompany the FUNDEF resources amount, particularly in concern in the financial resources (ratio) over plus. Finally, emphasize the importance of democratization in the relations between the state and civil society, elucidating and exciting reflections a: democratic participation in control of public recourses for education, educational management and civil society mobilization in access of public and cultural cash which the citizen has rights
Resumo:
This work describes the study and the implementation of the vector speed control for a three-phase Bearingless induction machine with divided winding of 4 poles and 1,1 kW using the neural rotor flux estimation. The vector speed control operates together with the radial positioning controllers and with the winding currents controllers of the stator phases. For the radial positioning, the forces controlled by the internal machine magnetic fields are used. For the radial forces optimization , a special rotor winding with independent circuits which allows a low rotational torque influence was used. The neural flux estimation applied to the vector speed controls has the objective of compensating the parameter dependences of the conventional estimators in relation to the parameter machine s variations due to the temperature increases or due to the rotor magnetic saturation. The implemented control system allows a direct comparison between the respective responses of the speed and radial positioning controllers to the machine oriented by the neural rotor flux estimator in relation to the conventional flux estimator. All the system control is executed by a program developed in the ANSI C language. The DSP resources used by the system are: the Analog/Digital channels converters, the PWM outputs and the parallel and RS-232 serial interfaces, which are responsible, respectively, by the DSP programming and the data capture through the supervisory system
Resumo:
Several research lines show that sleep favors memory consolidation and learning. It has been proposed that the cognitive role of sleep is derived from a global scaling of synaptic weights, able to homeostatically restore the ability to learn new things, erasing memories overnight. This phenomenon is typical of slow-wave sleep (SWS) and characterized by non-Hebbian mechanisms, i.e., mechanisms independent of synchronous neuronal activity. Another view holds that sleep also triggers the specific enhancement of synaptic connections, carrying out the embossing of certain mnemonic traces within a lattice of synaptic weights rescaled each night. Such an embossing is understood as the combination of Hebbian and non-Hebbian mechanisms, capable of increasing and decreasing respectively the synaptic weights in complementary circuits, leading to selective memory improvement and a restructuring of synaptic configuration (SC) that can be crucial for the generation of new behaviors ( insights ). The empirical findings indicate that initiation of Hebbian plasticity during sleep occurs in the transition of the SWS to the stage of rapid eye movement (REM), possibly due to the significant differences between the firing rates regimes of the stages and the up-regulation of factors involved in longterm synaptic plasticity. In this study the theories of homeostasis and embossing were compared using an artificial neural network (ANN) fed with action potentials recorded in the hippocampus of rats during the sleep-wake cycle. In the simulation in which the ANN did not apply the long-term plasticity mechanisms during sleep (SWS-transition REM), the synaptic weights distribution was re-scaled inexorably, for its mean value proportional to the input firing rate, erasing the synaptic weights pattern that had been established initially. In contrast, when the long-term plasticity is modeled during the transition SWSREM, an increase of synaptic weights were observed in the range of initial/low values, redistributing effectively the weights in a way to reinforce a subset of synapses over time. The results suggest that a positive regulation coming from the long-term plasticity can completely change the role of sleep: its absence leads to forgetting; its presence leads to a positive mnemonic change
Resumo:
This work describes the study and the implementation of the speed control for a three-phase induction motor of 1,1 kW and 4 poles using the neural rotor flux estimation. The vector speed control operates together with the winding currents controller of the stator phasis. The neural flux estimation applied to the vector speed controls has the objective of compensating the parameter dependences of the conventional estimators in relation to the parameter machine s variations due to the temperature increases or due to the rotor magnetic saturation. The implemented control system allows a direct comparison between the respective responses of the speed controls to the machine oriented by the neural rotor flux estimator in relation to the conventional flux estimator. All the system control is executed by a program developed in the ANSI C language. The main DSP recources used by the system are, respectively, the Analog/Digital channels converters, the PWM outputs and the parallel and RS-232 serial interfaces, which are responsible, respectively, by the DSP programming and the data capture through the supervisory system
Resumo:
This work presents a model of bearingless induction machine with divided winding. The main goal is to obtain a machine model to use a simpler control system as used in conventional induction machine and to know its behavior. The same strategies used in conventional machines were used to reach the bearingless induction machine model, which has made possible an easier treatment of the involved parameters. The studied machine is adapted from the conventional induction machine, the stator windings were divided and all terminals had been available. This method does not need an auxiliary stator winding for the radial position control which results in a more compact machine. Another issue about this machine is the variation of inductances array also present in result of the rotor displacement. The changeable air-gap produces variation in magnetic flux and in inductances consequently. The conventional machine model can be used for the bearingless machine when the rotor is centered, but in rotor displacement condition this model is not applicable. The bearingless machine has two sets of motor-bearing, both sets with four poles. It was constructed in horizontal position and this increases difficulty in implementation. The used rotor has peculiar characteristics; it is projected according to the stator to yield the greatest torque and force possible. It is important to observe that the current unbalance generated by the position control does not modify the machine characteristics, this only occurs due the radial rotor displacement. The obtained results validate the work; the data reached by a supervisory system corresponds the foreseen results of simulation which verify the model veracity