Made available in DSpace on 2014-06-12T15:51:26Z (GMT). No. of bitstreams: 2 arquivo3091_1.pdf: 1433589 bytes, checksum: cee30d09ca85980508dbf3f0ac6de0cd (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Constituindo fontes ricas de compostos farmacologicamente ativos, com um amplo espectro de atividades biológicas, as toxinas e enzimas presentes nos venenos das famílias Crotalidae e Viperidae estão associadas a diversas atividades biológicas, como hemorrágica, fibrinolítica, inibidora da agregação plaquetária, proteolítica, neurotóxica e miotóxica. Dentre os constituintes de venenos de serpentes, merece destaque o grupo formado pelas metaloproteases, que compreende uma grande família de toxinas, com aproximadamente 200 membros catalogados, envolvendo uma marcante diversidade de estruturas e funções biológicas. Em meio a essa diversidade estrutural e funcional, um subgrupo de metaloproteses do tipo PIII, que apresenta atividade indutora de apoptose, vêm sendo alvo de inúmeras pesquisas. Ainda assim, muito pouco se conhece a respeito dessas proteínas. Em torno de doze exemplares dessas metaloproteases, como VAP1 e 2 de venenos de Crotalus atrox, foram identificadas. Desde o isolamento e purificação dessas proteínas, toxinas com alta similaridade às VAPs têm sido caracterizadas e purificadas do veneno de outras espécies de Viperídeos, que habitam diferentes lugares na Terra. Baseado no importante papel que essas metaloproteases indutoras de apoptose vascular podem desempenhar na angiogênese, através da inibição do crescimento de células neoplásicas, devido à indução da apoptose das células vasculares que nutrem o tumor, impedindo o crescimento acelerado e descontrolado das células tumorais, nós investigamos a expressão de metaloproteases VAP-like da glândula de venenos de três viperídeos, representantes do território brasileiro. Por clonagem molecular e reação em cadeia da polimerase em tempo real quantitativa, um gene calibrador de Crotalus durissus terrificus, homólogo a VAP1, nomeado crotastatin, e demais genes homólogos VAP1/crotastatin-like da glândula de veneno de Bothrops atrox, Crotalus durissus cascavella e Lachesis muta rhombeata foram expressos em diferentes níveis. O batroxstatin, o precursor crotastatin-like, de B. atrox, é expresso 87 vezes mais que crotastatin-1, de C. d. cascavella, e 7.5 vezes mais que lachestatins, de L. m. rhombeata. Além do mais, análises estruturais, in silico, das sequências de aminoácidos indicam que batroxstatin-2, crotastatin e lachestatin-1 e -2 apresentam domínios estruturais e sítio de ligação ao metal, iguais aos de VAP1, sendo dessa forma inclusos em um ramo filogenético que compreende as toxinas indutoras de apoptose

Made available in DSpace on 2014-06-12T15:02:40Z (GMT). No. of bitstreams: 2 arquivo1195_1.pdf: 502946 bytes, checksum: 05de27e9cfcaa96d9a0be29bebb8ff1d (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2008 / Cascavéis mantidas em cativeiro sob estresse térmico apresentam redução na velocidade da digestão, alterações quantitativa e qualitativa da peçonha, o que sugere a modulação de genes relacionados à aclimatação a baixas temperaturas. O presente trabalho visou clonar uma fosfolipase e avaliar a expressão de genes relacionados a estresse em glândulas de peçonha de cascavéis da espécie Crotalus durissus cascavella (Cdcasca) submetidas a estresse térmico. Para tanto, a clonagem do cDNA de uma nova PLA2 foi realizada a partir da biblioteca de cDNA da glândula de peçonha de Cdcasca. A seqüência de aminoácidos deduzida dessa PLA2 indica que essa se enquadra no grupo das PLA2s ácidas, da classe II, cujos membros apresentam atividade enzimática. A fim de verificar o padrão de expressão após estresse térmico, os cDNA de glândulas de três cascavéis, provenientes da mesma ninhada, submetidas a extração da peçonha e, posteriormente, a temperaturas de 18°C (frio), 28 °C (controle) e 40° C (calor), por três dias, foram preparados e os transcritos de PLA2 e de proteínas de choque térmico (HSP70, HSP90, e HSF1) quantificados por PCR em tempo real. Os resultados mostraram que os níveis de transcritos de PLA2 foram 5,24 vezes mais altos nas glândulas de peçonha da serpente mantida no frio em relação ao controle, enquanto os transcritos de PLA2 das glândulas da serpente mantida no calor não apresentaram diferenças significativas. Os níveis de transcritos das HSPs e seu fator de transcrição (HSF1) não variaram de maneira apreciável na amostras. Os resultados provaram, pela primeira vez, influência da baixa temperatura na expressão de uma toxina na glândula de peçonha de C. d. cascavella, sugerindo que essas serpentes podem adaptar a composição da peçonha à condição de estresse térmico

Call number: LD2668 .T4 1966 G195 / Master of Science

<p> For an engineer, it is always a difficult task to deploy a distributed wireless sensor network for buildings, without initial planning of the infrastructure of the network. A robust network is one that provides entire connectivity without compromising the signal strength. Another important parameter to be considered is the cost of the network, which can be reduced by deploying the most optimized and resilient network. With this project, we have designed an interactive design tool using Matlab that can help an engineer to plan and place the router nodes before actual deployment. The reference methods are based on Dijkstra&rsquo;s algorithm, line based algorithm and clustering algorithm for placing of routers. In this project, we have used best from all the algorithms to present a novel approach for the placement of routers. This algorithm provides improved results than the reference methods and thus further reduces the cost of the network.</p>

The primary objective of this thesis is to develop a methodology for fast, yet accurate temperature estimation during design space exploration. Power and temperature of modern day systems have become important metrics in addition to performance. Static and dynamic power dissipation leads to an increase in temperature, which creates cooling and packaging issues. Furthermore, the transient thermal profile determines temperature gradients, hotspots and thermal cycles. Traditional solutions rely on cycle-accurate simulations of detailed micro-architectural structures and are slow. The thesis shows that the periodic power estimation is the key bottleneck in such approaches. It also demonstrates an approach (FastSpot) that integrates accurate thermal estimation into existing host-compiled simulations. The developed methodology can incorporate different sampling-based thermal models. It achieves a 32000x increase in simulation throughput for temperature trace generation, while incurring low measurement errors (0.06 K- transient,0.014 K- steady-state) compared to a cycle-accurate reference method. / text

Spores of foodborne pathogens such as Clostridium botulinum, Clostridium perfringens and Bacillus cereus are widely distributed in nature. Presence of those spores in food products, particularly C. botulinum spores in vacuum packed, ready-to-eat low-acid products, is a great safety concern. The research here described is a first effort towards understanding the role of the spore coat proteins in the inactivation of bacterial spore using high pressure processing. This study proposes a coat protein solubilization methodology using non-ionic detergents minimizing protein damage and compatible with spectroscopy methods. The methodology developed here was compared with approaches proposed in the literature with respect to protein yield, protein fractions identified, amino acid composition and suitability with spectroscopy techniques for the further analysis of coat proteins. Bacillus subtilis ATCC 6633 spore coat proteins were solubilized (n=3) using octyl-β-D-glucopyranoside (OGP) at room temperature and urea/sodium dodecyl sulphate (UDS) at 37C and 70C. Analysis of variance (ANOVA) showed no significant (95% confidence) differences between the three repetitions of the three spore coat protein solubilization methods. Protein yield was significantly larger (95% confidence) when using UDS at 70C as compared to UDS at 37C. OGP gave the lowest protein yield but allowed circular dichroism (CD) analysis of the spore coat protein solution with minimum blank signal. SDS-PAGE revealed that the UDS-70C coat protein solutions consisted of five major and six minor proteins ranging 6 to 65 kD while the OGP solution appear to consist of four major and nine minor bands in the same mw range. Amino acid analysis of the protein extracted by the OGP method was conducted using reverse phase HPLC (RP-HPLC) and compared with published information. The OGP spore coat protein solution showed a higher proportion of aspartate, glutamate, alanine and tyrosine. Pressure, heat and time effects were studied on spore coat proteins obtained from untreated and pressure-treated B. subtilis ATCC 6633 spores. Pressure treatments of spores, and of extracted spore coat protein solutions, at 50 kpsi (345 mPa) and 85 kpsi (586 mPa) for 10 and 30 min at constant 85C along with appropriate heat- and pressure-only controls and untreated sample, were used to study the effect of pressure, heat and time on spore coat proteins. Both spore coat protein solubilization procedures showed a significant reduction in protein yield for pressure-only, heat-only and pressure/heat treated spores when compared with untreated spores. When OGP-solubilized proteins from untreated spores were pressure treated, SDS-PAGE profile showed an increasing overall band intensity with increasing pressure and time. In the case of protein solution obtained from pressure-treated spores the electrophoretic pattern showed the loss of higher molecular weight proteins. The significance of this study is that for the first time we have observed extensive changes on spore coat proteins caused by pressure, as well as heat treatments. Future studies will examine what is the probable physiological role of the proteins damaged by these physical treatments. An advantage of the protein solubilization here developed will allow the application of spectroscopy techniques to characterize changes in spore coat proteins. / Graduation date: 2003

Brain-computer interface (BCI) technology provides a means of communication that allows individuals with severely impaired movement to communicate with assistive devices using the electroencephalogram (EEG) or other brain signals. Dealing with the unknown embedded noise within the raw EEG and the inherent lower bandwidth of BCI are still two of the major challenges in making BC! practical for day-to-day use. The raw EEG signal recorded non-invasively during motor i ~~~y (MI) is intrinsically " ." embedded with non-Gaussian noise while the actual noise-free EEG has so far not been attained. Therefore, a filtering approach is needed to remove noise. A novel quantum mechanics motivated alternative neural information processing architecture using the Schrodinger wave equation (SWE) is proposed to filter and thereby enhance the information from the otherwise noisy EEG signals. This novel filtering approach is constructed using a layer of neurons within the neural network framework, referred to as the Recurrent Quantum Neural Network (RQNN) that recurrently computes a time-varying probability density function (pdf) for the measurement of the observed signal. The raw EEG sample is encoded in terms of a particle-like wave packet that can be used to accurately filter noise from the EEG using an unsupervised learning scheme without making any assumption about the underlying distribution. The RQNN enhanced EEG signal is more easily classified than the raw signal. Another major challenge in two-class BC! systems is also addressed in this thesis, namely the inherent lower bandwidth of the communication channel that may lead to a sluggish response in suitably controlling a mobile robotic device. An intelligent and adaptive user interface, which plays a very important role as a front-end display for the BCI user is proposed. The framework of the proposed intelligent Adaptive User Interface (iAUI) i.e., the brain-robot interface is consistent for a range of applications e.g., for controlling either a mobile robot or a robotic arm. The iAUI for mobile robot offers a real-time prioritized list of all the options for selection by the user. Prioritized update ofthe iAUI is possible by utilizing information obtained from the sonar sensors mounted on the mobile robot. Through iAUI the user is always offered the most likely choice, thereby improving the information transfer rate. Similarly, the interface for controlling the robot arm displays the list of available objects for user selection depending on the real-time information from the camera view of the robot arm. Results on multiple participants show that both the main contributions, the RQNN filtering and the iAUI address to a large extent the issues of dealing with unknown embedded noise within the raw EEG and the inherent lower bandwidth of BCI. xv Abstract

No description available.

No description available.

The cancer stem cell (CSC) model of carcinogenesis and progression posits that within a tumor lies a subpopulation of cells that solely possess the ability to initiate a tumor and to differentiate into tumor cell lineages. Although the behavior of such cells is known, the challenge is to identify factors that characterize the CSC subpopulation. In this thesis, cell lines were identified that, when grown in three-dimensions, gave rise to organized colonies containing lumens originating from differentiating cells (“lumen lines”) and to densely-packed, spherical colonies originating from non-differentiating cells (“dense lines”). A microarray comparison of the pair identified genes upregulated in dense lines, including CD55 and BMI1, and in lumen lines, including CDX1 (Chapter 3). CD55 was used to isolate CD55high CSCs via flow cytometry that are able to self-renew, differentiate, initiate more colonies, proliferate more rapidly and exhibit an increased G2/M cell cycle population as opposed to unfractionated cells. Furthermore, the CD55high cells were able to give rise to more differentiated, lumen colonies in vitro, indicating that CD55 enriches for cells possessing a capacity to differentiate, and were able to enrich the CD24highCD44high putative CSC population further (Chapter 4). CDNA induction of BMI1 and CDX1 expression led to increased clonogenicity/proliferation and decreased clonogenicity/proliferation, respectively, and incorporation of a CDX1 reporter construct into the SW1222 cell line identified CDX1+ cells as a low-expressing population of CD55 (Chapter 5). Finally, co-culture of cell lines in an in vivo-like environment with intestinal myofibroblasts promoted the CSC population by enhancing clonogenicity, proliferation and expression of CD55 (Chapter 6). The results of this thesis implicate CD55 as a potent marker of colorectal cancer stemness, link the expression of BMI1 and CDX1 to cancer stemness and differentiation, respectively, and identify a role for the in vivo stem cell niche in maintaining the CSC population.