Obtenção de concentrado proteico do farelo de arroz e avaliação das propriedades químicas e funcionais

Esta dissertação é composta por 5 artigos.

Produção de carboidratos a partir do efluente de laticínios tratado por cianobactéria

Nesta tese foi demonstrado o potencial de produção de carboidratos por Aphanothece microscopica Nägeli cultivada no efluente oriundo de uma indústria de laticínios. Para tanto, o trabalho é composto de quatro artigos que objetivaram avaliar a produção de carboidratos em função da temperatura, inóculo e razões C/N e N/P do elfluente, bem como a possibilidade de reúso da água residuária. Foram utilizadas temperaturas de (10, 20 e 30ºC) e inóculo (100, 200 e 300 mg.L-1). A melhor condição indicada foi quando utilizou-se a temperatura de 30°C e 200 mg.L-1 de inóculo. Na sequência, considerando a temperatura e a concentração celular selecionada, foi estudada a influência das razões C/N e N/P na produção de carboidratos. Para tal, C/N (20, 40 e 60) e N/P (5, 10 e 15) na produção de carboidratos extracelulares foram avaliadas em cultivos a 30°C, tendo como inóculo 200 mg.L-1. Os melhores resultados obtidos, foram quando foi utilizado C/N 60 e N/P 10. Uma vez definidas as melhores condições de produção de carboidratos, foi estudado o processo de separação de biomassa do meio de cultivo, a partir dos coagulantes FeCl3, Al2(SO4)3 e tanino. O efeito dos coagulantes na separação da biomassa foram estudados, quanto ao pH (6,0, 7,0 e 8,0) e concentração de coagulantes (50, 300 e 550 mg.L-1), utilizando como parâmetro de medida, a eficiência de remoção de DQO, turbidez e sólidos suspensos (SS). Os resultados demonstraram que as concentrações de coagulantes influenciaram significativamente ao nível de significância de 5 %, na separação da biomassa, com eficiência significativa na remoção da DQO, turbidez e SS. A melhor condição avaliada foi a que utilizou tanino na concentração de 300 mg.L-1 e pH 7,0, o que resultou em uma água residuária com remoção média de 96 % da turbidez, com potencial de ser reutilizada. Por fim, foi realizada a identificação de carboidratos gerados por Aphanothece microscopica Nägeli. Os resultados evidenciaram uma biomassa com até 33,5 % de carboidratos totais, perfazendo uma fração de carboidratos extracelulares, na fase estacionária de crescimento celular, de aproximadamente 25 % e 8 % os carboidratos da parede celular. Ficou demonstrado ainda que a composição dos carboidratos extracelulares do microorganismo em estudo é constituído por mono e dissacarídeos perfazendo concentrações na ordem de 12,88 % de glicose, 3,54 % de rafinose, 3,43 % sacarose, 2,13 % de frutose e 2,45 % de ribose. Ficou demonstrado o potencial de produção de carboidratos por Aphanothece microscopica Nägeli quando cultivada no efluente da indústria de laticínios.

Exploring redox-driven self-assembly of mixed metal polyoxometalates

How can we control the experimental conditions towards the isolation of specific structures? Why do particular architectures form? These are some challenging questions that synthetic chemists try to answer, specifically within polyoxometalate (POM) chemistry, where there is still much unknown regarding the synthesis of novel molecular structures in a controlled and predictive manner. This work covers a wide range of POM chemistry, exploring the redox self-assembly of polyoxometalate clusters, using both “one-pot”, flow and hydrothermal conditions. For this purpose, different vanadium, molybdenum and tungsten reagents, heteroatoms, inorganic salts and reducing agents have been used. The template effect of lone-pair containing pyramidal heteroatoms has been investigated. Efforts to synthesize new POM clusters displaying pyramidal heteroanions (XO32-, where X= S, Se, Te, P) are reported. The reaction of molybdenum with vanadium in the presence of XO32- heteroatoms is explored, showing how via the cation and experimental control it is possible to direct the self-assembly process and to isolate isostructural compounds. A series of four isostructural (two new, namely {Mo11V7P} and {Mo11V7Te} and two already known, namely {Mo11V7Se} and {Mo11V7S} disordered egg-shaped Polyoxometalates have been reported. The compounds were characterized by X-ray structural analysis, TGA, UV-Vis, FT-IR, Elemental and Flame Atomic Absorption Spectroscopy (FAAS) analysis and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Cyclic Voltammetry measurements have been carried out in all four compounds showing the effect of the ionic density of the heteroatom on the potential. High-Resolution ESI-MS studies have revealed that the structures retain their integrity in solution. Efforts to synthesize new mixed-metal compounds led to isolation, structural, and electronic characterization of the theoretically predicted, but experimentally elusive δ-isomer of the Keggin polyoxometalate cluster anion, {H2W4V9O33(C6H13NO3)}, by the reaction of tungstate(VI) and vanadium(V) with triethanolammonium ions (TEAH), acting as a tripodal ligand grafted to the surface of the cluster. Control experiments (in the absence of the organic compound) have proven that the tripodal ligand plays crucial role on the formation of the isomer. The six vanadium metal centres, which consist the upper part of the cluster, are bonded to the “capping” TEA tripodal ligand. This metal-ligand bonding directs and stabilises the formation of the final product. The δ-Keggin species was characterized by single-crystal X-ray diffraction, FT-IR, UV-vis, NMR and ESI-MS spectrometry. Electronic structure and structure-stability correlations were evaluated by means of DFT calculations. The compounds exhibited photochromic properties by undergoing single-crystal-to-single-crystal (SC-SC) transformations and changing colour under light. Non-conventional synthetic approaches are also used for the synthesis of the POM clusters comparing the classical “one-pot” reaction conditions and exploring the synthetic parameters of the synthesis of POM compounds. Reactions under hydrothermal and flow conditions, where single crystals that depend on the solubility of the minerals under hot water and high pressure can be synthesized, resulted in the isolation of two isostructural compounds, namely, {Mo12V3Te5}. The compound isolated from a continuous processing method, crystallizes in a hexagonal crystal system, forming a 2D porous plane net, while the compound isolated using hard experimental conditions (high temperature and pressure) crystallizes in monoclinic system, resulting in a different packing configuration. Utilizing these alternative synthetic approaches, the most kinetically and thermodynamically compounds would possibly be isolated. These compounds were characterised by single-crystal X-ray diffraction, FT-IR and UV-vis spectroscopy. Finally, the redox-controlled driven oscillatory template exchange between phosphate (P) and vanadate (V) anions enclosed in an {M18O54(XO4)2} cluster is further investigated using UV-vis spectroscopy as a function of reaction time, showed that more than six complete oscillations interconverting the capsule species present in solution from {P2M18} to {V2M18} were possible, provided that a sufficient concentration of the TEA reducing agent was present in solution. In an effort to investigate the periodicity of the exchange of the phosphate and vanadate anions, time dependent Uv-vis measurements were performed for a period at a range of 170-550 hours. Different experimental conditions were also applied in order to investigate the role of the reducing agent, as well as the effect of other experimental variables on the oscillatory system.

Efeitos do treinamento resistido com máquinas pneumáticas e resistência elástica progressiva na força, capacidade funcional e equilíbrio em mulheres idosas : um ensaio clínico randomizado

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Educação Física, Programa de Pós-Graduação Strictu-Sensu em Educação Física, 2015.

Reconstruction of inclusions in photothermal imaging

Photothermal imaging allows to inspect the structure of composite materials by means of nondestructive tests. The surface of a medium is heated at a number of locations. The resulting temperature field is recorded on the same surface. Thermal waves are strongly damped. Robust schemes are needed to reconstruct the structure of the medium from the decaying time dependent temperature field. The inverse problem is formulated as a weighted optimization problem with a time dependent constraint. The inclusions buried in the medium and their material constants are the design variables. We propose an approximation scheme in two steps. First, Laplace transforms are used to generate an approximate optimization problem with a small number of stationary constraints. Then, we implement a descent strategy alternating topological derivative techniques to reconstruct the geometry of inclusions with gradient methods to identify their material parameters. Numerical simulations assess the effectivity of the technique.

Nutritional status in children with esophageal stenosis and dysphagia associated with caustic ingestion

Introduction: Caustic ingestion (CI) in children and adolescents may lead to esophageal burns, esophageal stenosis and secondary dysphagia. These complications may limit the normal feeding process leading to malnutrition and growth impairment. Aims: Our aim was to evaluate the nutritional status and its association with dysphagia and esophageal stenosis in children with CI. Methods: Sixty-two patients with caustic ingestion treated at a pediatric referral hospital were included in this cross-sectional study. Independent variables were dysphagia/normal swallowing and esophageal stenosis/normal barium-swallow. The dependent variables were growth and nutritional status evaluated by anthropometry. Analysis: χ² test, OR, 95% CI, kappa test and Student's t-test. Results: The average age at the time of CI was 39.7 months; 38.7% of the patients were girls. Endoscopy performed upon admission revealed erosive esophagitis (II-b, III-a, and III-b) in 46 (77.8%) of the patients, dysphagia in twenty-four (38.7%) and esophageal stenosis in forty (64.5%). Both complications occurred simultaneously in 20 children (32.3%, kappa = 0.3, p = 0.014). The z-score of height-for-age was below -2 SD in five children (8.1%). The z score of body mass index (BMI) was < -2 SD in three children (4.8%) and it was above +1 SD in 24.2%. The z-score means of the arm anthropometric indicators of fat stores and muscle mass in both the dysphagia and esophageal stenosis groups were located in the negative area of the z-score curve and their values differed significantly from the z-scores of the non-dysphagia and non-stenosis groups. Conclusions: The proportion of erosive esophagitis, esophageal stenosis and dysphagia was high. Children with dysphagia and/or esophageal stenosis associated with CI had lower fat stores and muscle mass than the cases without esophageal complications.

Feasibility of resting-state microstates neurofeedback

Despite major progress, currently available treatment options for patients suffering from schizophrenia remain suboptimal. Antipsychotic medication is one such option, and is helpful in acute phases of the disease. However, antipsychotics cause significant side-effects that often require additional medication, and can even trigger the discontinuation of treatment. Taken together, along with the fact that 20-30% of patients are medication-resistant, it is clear that new medical care options should be developed for patients with schizophrenia. Besides medication, an emerging option to treat psychiatric symptoms is through the use of neurofeedback. This technique has proven efficacy for other disorders and, more importantly, has also proven to be feasible in patients with schizophrenia. One of the major advantages of this approach is that it allows for the influence of brain states that otherwise would be inaccessible; i.e. the physiological markers underlying psychotic symptoms. EEG resting-state microstates are a very interesting electrophysiological marker of schizophrenia symptoms. Precisely, a specific class of resting-state microstates, namely microstate class D, has consistently been found to show a temporal shortening in patients with schizophrenia compared to controls, and this shortening is correlated with the presence positive psychotic symptoms. Under the scope of biological psychiatry, appropriate treatment of psychotic symptoms can be expected to modify the underlying physiological markers accompanying behavioral manifestations of a disease. We reason that if abnormal temporal parameters of resting-state microstates seem to be related to positive symptoms in schizophrenia, regulating this EEG feature might be helpful as a treatment for patients. The goal of this thesis was to prove the feasibility of microstate class D contribution self-regulation via neurofeedback. Given that no other study has attempted to regulate microstates via neurofeedback, we first tested its feasibility in a population of healthy subjects. In the first paper we describe the methodological characteristics of the neurofeedback protocol and its implementation. Neurofeedback performance was assessed by means of linear mixed effects modeling, which provided a complete profile of the neurofeedback’s training response within and between-subjects. The protocol included 20 training sessions, and each session contained three conditions: baseline (resting-state) and two active conditions: training (auditory feedback upon self-regulation performance) and transfer (self-regulation with no feedback). With linear modeling we obtained performance indices for each of them as follows: baseline carryover (baseline increments time-dependent) and learning and aptitude for each of the active conditions. Learning refers to the increase/decrease of the microstate class D contribution, time-dependent during each active condition, and aptitude refers to the constant difference of the microstate class D contribution between each active condition and baseline independent of time. The indices provided are discussed in terms of tailoring neurofeedback treatment to individual profiles so that it can be applied in future studies or clinical practice. In our sample of participants, neurofeedback proved feasible, as all participants at least showed positive results in one of the aforementioned learning indices. Furthermore, between-subjects we observed that the contribution of microstate class D across-sessions increased by 0.42% during baseline, 1.93% during training trials, and 1.83% during transfer. This range is expected to be effective in treating psychotic symptoms in patients. In the second paper presented in this thesis, we explored the possible predictors of neurofeedback success among psychological variables measured with questionnaires. An interesting finding was the negative correlation between “motivational incongruence” and some of the neurofeedback performance indices. Even though this finding requires replication, we discuss it in terms of the interfering effects of incompatible psychological processes with neurofeedback training requirements. In the third paper, we present a meta-analysis on all available studies that have related resting-state microstate abnormalities and schizophrenia. We obtained medium effect sizes for two microstate classes, namely C and D. Combining the meta-analysis results with the fact that microstate class D abnormalities are correlated with the presence of positive symptoms in patients with schizophrenia, these results add further support for the training of this precise microstate. Overall, the results obtained in this study encourage the implementation of this protocol in a population of patients with schizophrenia. However, future studies will have to show whether patients will be able to successfully self-regulate the contribution of microstate class D and, if so, whether this regulation will have an impact on symptomatology.

Probabilistic methods for seasonal forecasting in a changing climate: Cox-type regression models.

For climate risk management, cumulative distribution functions (CDFs) are an important source of information. They are ideally suited to compare probabilistic forecasts of primary (e.g. rainfall) or secondary data (e.g. crop yields). Summarised as CDFs, such forecasts allow an easy quantitative assessment of possible, alternative actions. Although the degree of uncertainty associated with CDF estimation could influence decisions, such information is rarely provided. Hence, we propose Cox-type regression models (CRMs) as a statistical framework for making inferences on CDFs in climate science. CRMs were designed for modelling probability distributions rather than just mean or median values. This makes the approach appealing for risk assessments where probabilities of extremes are often more informative than central tendency measures. CRMs are semi-parametric approaches originally designed for modelling risks arising from time-to-event data. Here we extend this original concept beyond time-dependent measures to other variables of interest. We also provide tools for estimating CDFs and surrounding uncertainty envelopes from empirical data. These statistical techniques intrinsically account for non-stationarities in time series that might be the result of climate change. This feature makes CRMs attractive candidates to investigate the feasibility of developing rigorous global circulation model (GCM)-CRM interfaces for provision of user-relevant forecasts. To demonstrate the applicability of CRMs, we present two examples for El Ni ? no/Southern Oscillation (ENSO)-based forecasts: the onset date of the wet season (Cairns, Australia) and total wet season rainfall (Quixeramobim, Brazil). This study emphasises the methodological aspects of CRMs rather than discussing merits or limitations of the ENSO-based predictors.

Prevalencia de neuropatía diabética y factores de riesgo, en pacientes de los clubes de diabetes del distrito 01d01 de Cuenca-Ecuador, 2015

Antecedentes De las complicaciones crónicas de la diabetes, la más destacada es la neuropatía. Esta produce disminución en la calidad de vida, ya que conlleva al paciente a tener dificultades como: dolor, parestesias, ulceraciones, e incluso alteración en la deambulación. Objetivos Determinar la prevalencia de neuropatía simétrica distal en pacientes que integran los clubes de diabéticos del distrito 01D01 y su relación con sus estilos de vida. Materiales y Métodos Es un estudio transversal con una muestra de 162 pacientes, seleccionados al azar, sobre la base del 30% de prevalencia de neuropatía, con un nivel de confianza del 95% y error de inferencia del 5%. Fueron aplicados dos cuestionarios avalados (NSS+NDS). Para el análisis, usamos el programa SPSS 15. Las variables demográficas, se analizaron por estadística descriptiva. La relación entre las variables dependientes y variables independientes se evaluó a través de la razón de prevalencia, con un intervalo de confianza del 95%, chi cuadrado y valor de p. Resultados La prevalencia de neuropatía diabética es del 54.9%, en hombres 73.7% y en mujeres 49.2%. Los factores protectores son: Recibir indicaciones sobre cuidado de los pies con 66.7% (RP 2 y valor de p 0.033), y el buen control de glucosa en sangre con el 95.9% (RP 2.3 y valor de p 0.001). Conclusiones La neuropatía diabética simétrica distal se presenta más en hombres que en mujeres. Además se encontró que el buen control de glucosa en sangre y recibir indicaciones sobre cuidado de los pies, disminuyen el riesgo de neuropatía.

Triptolide induces cell apoptosis in human stomach cancer cell via caspase 3-dependent cascade pathway

Purpose: To evaluate the effect of triptolide on the induction of cell apoptosis in human gastric cancer BGC-823 cells. Methods: The cytotoxicity of triptolide was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay. The effect of triptolide on cell proliferation was measured using lactate dehydrogenase (LDH) assay. Cell apoptosis was determined by Annexin V/propidium iodide (PI) double-staining assay. Results: MTT results indicate that triptolide significantly decreased cancer cell numbers in dose- and time-dependent manners in MTT assay. Data from LDH assay showed that triptolide markedly induced cytotoxicity in gastric cancer cells. Triptolide also remarkably induced both early and late apoptotic process in BGC-823 cells. In addition, the compound down-regulated the expression of anti-apoptotic Bcell lymphoma-2 (bcl-2) and up-regulated the expression of pro-apoptotic BCL-2-associated X (bax) in a dose-dependent manner. Furthermore, the pro-apoptotic activity of triptolide was involved in the activation of caspase-3 pathway in BGC-823 cells. Conclusion: Taken together, the findings strongly indicates that the pro-apoptotic activity of triptolide is regulated by caspase 3-dependent cascade pathway, and thus needs to be further developed for cancer therapy.

Les facteurs affectant les taux de réussite des cours d’anglais et de sciences humaines des étudiants dans les programmes de formation technique

A large percentage of Vanier College's technology students do not attain their College degrees within the scheduled three years of their program. A closer investigation of the problem revealed that in many of these cases these students had completed all of their program professional courses but they had not completed all of the required English and/or Humanities courses. Fortunately, most of these students do extend their stay at the college for the one or more semesters required for graduation, although some choose to go on into the workforce without returning to complete the missing English and/or Humanities and without their College Degrees. The purpose of this research was to discover if there was any significant measure of association between a student's family linguistic background, family cultural background, high school average, and/or College English Placement Test results and his or her likelihood of succeeding in his or her English and/or Humanities courses within the scheduled three years of the program. Because of both demographic differences between 'hard' and 'soft' technologies, including student population, more specifically gender ratios and student average ages in specific programs; and program differences, including program writing requirements and types of practical skill activities required; in order to have a more uniform sample, the research was limited to the hard technologies where students work hands-on with hardware and/or computers and tend to have overall low research and writing requirements. Based on a review of current literature and observations made in one of the hard technology programs at Vanier College, eight research questions were developed. These questions were designed to examine different aspects of success in the English and Humanities courses such as failure and completion rates and the number of courses remaining after the end of the fifth semester and as well examine how the students assessed their ability to communicate in English. The eight research questions were broken down into a total of 54 hypotheses. The high number of hypotheses was required to address a total of seven independent variables: primary home language, high school language of instruction, student's place of birth (Canada, Not-Canada), student's parents' place of birth (Both-born-in-Canada, Not-both-born-in-Canada), high school averages and English placement level (as a result of the College English Entry Test); and eleven dependent variables: number of English completed, number of English failed, whether all English were completed by the end of the 5th semester (yes, no), number of Humanities courses completed, number of Humanities courses failed, whether all the Humanities courses were completed by the end of the 5th semester (yes, no), the total number of English and Humanities courses left, and the students' assessments of their ability to speak, read and write in English. The data required to address the hypotheses were collected from two sources, from the students themselves and from the College. Fifth and sixth semester students from Building Engineering Systems, Computer and Digital Systems, Computer Science and Industrial Electronics Technology Programs were surveyed to collect personal information including family cultural and linguistic history and current language usages, high school language of instruction, perceived fluency in speaking, reading and writing in English and perceived difficulty in completing English and Humanities courses. The College was able to provide current academic information on each of the students, including copies of college program planners and transcripts, and high school transcripts for students who attended a high school in Quebec. Quantitative analyses were done on the data using the SPSS statistical analysis program. Of the fifty-four hypotheses analysed, in fourteen cases the results supported the research hypotheses, in the forty other cases the null hypotheses had to be accepted. One of the findings was that there was a strong significant association between a student's primary home language and place of birth and his or her perception of his or her ability to communicate in English (speak, read, and write) signifying that both students whose primary home language was not English and students who were not born in Canada, considered themselves, on average, to be weaker in these skills than did students whose primary home language was English. Although this finding was noteworthy, the two most significant findings were the association found between a student's English entry placement level and the number of English courses failed and the association between the parents' place of birth and the student's likelihood of succeeding in both his or her English and Humanities courses. According to the research results, the mean number of English courses failed, on average, by students placed in the lowest entry level of College English was significantly different from the number of English courses failed by students placed in any of the other entry level English courses. In this sample students who were placed in the lowest entry level of College English failed, on average, at least three times as many English courses as those placed in any of the other English entry level courses. These results are significant enough that they will be brought to the attention of the appropriate College administration. The results of this research also appeared to indicate that the most significant determining factor in a student's likelihood of completing his or her English and Humanities courses is his or her parents' place of birth (both-born-in-Canada or not-both-born-in-Canada). Students who had at least one parent who was not born in Canada, would, on average, fail a significantly higher number of English courses, be significantly more likely to still have at least one English course left to complete by the end of the 5th semester, fail a significantly higher number of Humanities courses, be significantly more likely to still have at least one Humanities course to complete by the end of the 5th semester and have significantly more combined English and Humanities courses to complete at the end of their 5th semester than students with both parents born in Canada. This strong association between students' parents' place of birth and their likelihood of succeeding in their English and Humanities courses within the three years of their program appears to indicate that acculturation may be a more significant factor than either language or high school averages, for which no significant association was found for any of the English and Humanities related dependent variables. Although the sample size for this research was only 60 students and more research needs to be conducted in this area, to see if these results are supported with other groups within the College, these results are still significant. If the College can identify, at admission, the students who will be more likely to have difficulty in completing their English and Humanities courses, the College will now have the opportunity to intercede during or before the first semester, and offer these students the support they require in order to increase their chances of success in their education, whether it be classes or courses designed to meet their specific needs, special mentoring, tutoring or other forms of support. With the necessary support, the identified students will have a greater opportunity of successfully completing their programs within the scheduled three years, while at the same time the College will have improved its capacity to meeting the needs of its students.

Caracterización de trastornos musculo esqueléticos en trabajadores de dos empresas de servicios en Bogotá D.C 2015

Objetivo: El objetivo de este estudio fue determinar la prevalencia de los trastornos músculoesqueléticos y la asociación con factores sociodemográficos y hábitos de vida en trabajadores de las áreas administrativa y operativa de dos empresas de servicio de la ciudad de Bogotá 2015. Materiales y Métodos: Se realizó un estudio de corte transversal, con información secundaria, procedente de bases de datos suministrada por las dos empresas con 696 registros de trabajadores de servicios generales, y 943 registros de trabajadores del área administrativa, para un total de 1639 registros, en los cuales se evaluó la presencia de síntomas osteomusculares clasificados por segmento. Adicionalmente se contaba con información de características sociodemográficas y estilos de vida de estos trabajadores. Se obtuvieron las distribuciones de frecuencias absolutas y relativas para las variables cualitativas, y las medidas de tendencia central y de dispersión para las variables cuantitativas. Para establecer la asociación entre factores sociodemográficos con las variables dependientes se utilizó la prueba chi2 de asociación. Resultados: La prevalencia de molestia o dolor en los diferentes segmentos corporales fue de 21.5 % (n = 203) en cuello para la población administrativa y de 17.5% (n = 148) en mano y muñeca derecha para la población de servicios generales. Vale la pena aclarar que el diagnóstico médico más frecuente referido por la población en estudio fue traumas en musculo, bursa tendón y/o ligamento con 10.5% en la población administrativa y con el 12.4% en la población de servicios generales. De las asociaciones significativas entre diagnósticos presentes y hábitos de vida y sueño se encontró que sueño no reparador se asoció significativamente con enfermedad general de músculos y huesos (p = 0.001), enfermedad o trauma activo de tejidos blandos (p = 0,000) y antecedente o enfermedad actual de columna vertebral (p = 0,000). De manera similar, el consumo de medicamentos para conciliar el sueño se asoció con enfermedad de tejidos blandos (p = 0,000) y enfermedad actual de columna vertebral (p = 0,000). El consumo de café (p = 0.001) y el sedentarismo (p = 0.031) están asociados con la enfermedad general de músculos y huesos. Conclusiones: Los TME son un factor de alta prevalencia en la población trabajadora de Colombia, y como se demostró en este estudio, afectan a la población de las empresas de servicio. Se evidencia cada vez más que los segmentos corporales más afectados en la población administrativa, son cabeza y cuello, debido a las posturas mantenidas por largos periodos de tiempo, y en la población de servicios se encontró molestia y dolor en muñecas y manos debido a los movimientos repetitivos que deben de realizar durante la jornada laboral. Se hace necesario profundizar más en la asociación significativa de los trastornos del sueño y la presencia de los TME, ya que se encontró una relación importante entre estos dos.

Experimental and numerical investigation on short and long term performance of macro-synthetic fibre reinforced concrete materials

Fibre Reinforced Concretes are innovative composite materials whose applications are growing considerably nowadays. Being composite materials, their performance depends on the mechanical properties of both components, fibre and matrix and, above all, on the interface. The variables to account for the mechanical characterization of the material, could be proper of the material itself, i.e. fibre and concrete type, or external factors, i.e. environmental conditions. The first part of the research presented is focused on the experimental and numerical characterization of the interface properties and short term response of fibre reinforced concretes with macro-synthetic fibers. The experimental database produced represents the starting point for numerical models calibration and validation with two principal purposes: the calibration of a local constitutive law and calibration and validation of a model predictive of the whole material response. In the perspective of the design of sustainable admixtures, the optimization of the matrix of cement-based fibre reinforced composites is realized with partial substitution of the cement amount. In the second part of the research, the effect of time dependent phenomena on MSFRCs response is studied. An extended experimental campaign of creep tests is performed analysing the effect of time and temperature variations in different loading conditions. On the results achieved, a numerical model able to account for the viscoelastic nature of both concrete and reinforcement, together with the environmental conditions, is calibrated with the LDPM theory. Different type of regression models are also elaborated correlating the mechanical properties investigated, bond strength and residual flexural behaviour, regarding the short term analysis and creep coefficient on time, for the time dependent behaviour, with the variable investigated. The experimental studies carried out emphasize the several aspects influencing the material mechanical performance allowing also the identification of those properties that the numerical approach should consider in order to be reliable.

Neurogeometry of reaching

The purpose of the thesis is to develop a model for the functional behaviour of neurons in the primary motor cortex (M1) responsible for arm reaching movements. From Georgopoulos neurophysiological data, we provide a first bundle structure compatible with the hypercolumnar organization and with the position-direction selectivity of motor cortical cells. We then extend this model to encode the direction of arm movement which varies in time, as experimentally measured by Hatsopoulos by introducing the notion of movement fragments. We provide a sub-Riemannian model which describes the time-dependent directional selectivity of cells though integral curves of the geometric structure we set up. The sub-Riemannian distance we define allows to implement a grouping algorithm able to detect a set of hand motor trajectories. These paths, identified by using a kernel defined in terms of kinematic variables, are compatible with the motor primitives obtained from neurophysiological results by spectral analysis applied directly on cortical variables. In a second part of the work, we propose geodesics in this space as an alternative model of models for arm movement trajectories. We define a special class of curves, called admissible, on which to study the geodesics problem: we provide a connectivity property in terms of admissible paths and the existence of normal length minimizers. Admissible geodesics are used as a model of reaching paths, finding a first validation through Flash and Hogan minimizing trajectories.

Neuromuscular Activity Of Bothrops Fonsecai Snake Venom In Vertebrate Preparations.

The neuromuscular activity of venom from Bothrops fonsecai, a lancehead endemic to southeastern Brazil, was investigated. Chick biventer cervicis (CBC) and mouse phrenic nerve-diaphragm (PND) preparations were used for myographic recordings and mouse diaphragm muscle was used for membrane resting potential (RP) and miniature end-plate potential (MEPP) recordings. Creatine kinase release and muscle damage were also assessed. In CBC, venom (40, 80 and 160μg/ml) produced concentration- and time-dependent neuromuscular blockade (50% blockade in 85±9 min and 73±8 min with 80 and 160μg/ml, respectively) and attenuated the contractures to 110μM ACh (78-100% inhibition) and 40mM KCl (45-90% inhibition). The venom-induced decrease in twitch-tension in curarized, directly-stimulated preparations was similar to that in indirectly stimulated preparations. Venom (100 and 200μg/ml) also caused blockade in PND preparations (50% blockade in 94±13 min and 49±8 min with 100 and 200μg/ml, respectively) but did not alter the RP or MEPP amplitude. In CBC, venom caused creatine kinase release and myonecrosis. The venom-induced decrease in twitch-tension and in the contractures to ACh and K(+) were abolished by preincubating venom with commercial antivenom. These findings indicate that Bothrops fonsecai venom interferes with neuromuscular transmission essentially through postsynaptic muscle damage that affects responses to ACh and KCl. These actions are effectively prevented by commercial antivenom.