Pour pouvoir être autonomes dans un environnement complexe, les humains comme les systèmes artificiels doivent posséder un apprentissage souple et capable de s’adapter au changement. Dans cette thèse, nous nous intéressons à comment cette autonomie peut être obtenue par interactions entre les différents systèmes d’apprentissage de notre cerveau. Pour cela, nous modélisons dans une approche inspirée de la biologie le comportement de certaines des parties du cerveau impliquées dans les apprentissages répondant et opérant, et observons comment leurs interactions permettent un apprentissage flexible dans des tâches impliquant des changements comme l’extinction et le reversal. / In a complex environment, humans and artificials systems need a flexible learning system to adapt themselves to situations which can change. In this thesis, we study how autonomy can be the result of interactions between the different learning systems of our brain. In particular, in a biologically inspired approach, we model different parts of the brain involved in respondant and operant conditioning, et show how their interactions can promote flexible learning in tasks in which situation can change, like extinction or reversal.

Tertiary treatment methods were tested on secondary effluent from an abattoir biological wastewater treatment plant with the purpose of renovating it for re-use in the abattoir. The colour and dissolved organic matter could be removed to such an extent that the water would comply with water of insignificant health risk (Department of Health). The treatment process sequence proven to be effective in upgrading this water so insignificant health risk standard were coagulation with a polymer blend, separation, ozonation, filtration and activated carbon filtration. The development of biologically activated carbon in practice was accepted as inevitable and desirable for optimum water quality, but not tested. A deciding factor in the selection of an appropriate treatment was that the final water would also have acceptable corrosion properties. / Dissertation (MSc)--University of Pretoria, 2010. / Chemical Engineering / unrestricted

How can science possibly understand the organ through which the Universe knows itself? The scientific method can be used to study how electro-chemical signals represent information in the brain. However, modelling it by simulating its structures and functions is a computation- and communication-intensive task. Whilst supercomputers offer great computational power, brain-scale models are challenging in terms of communication overheads and power consumption. Dedicated neural hardware can be used to enhance simulation performance, but it is often optimised for specific models. While performance and flexibility are desirable simulation features, there is no perfect modelling platform, and the choice is subordinate to the specific research question being investigated. In this context SpiNNaker constitutes a novel parallel architecture, with communication and memory accesses optimised for spike-based computation, permitting simulation of large spiking neural networks in real time. To exploit SpiNNaker's performance and reconfigurability fully, a neural network model must be translated from its conceptual form into data structures for a parallel system. This thesis presents a flexible approach to distributing and mapping neural models onto SpiNNaker, within the constraints introduced by its specialised architecture. The conceptual map underlying this approach characterizes the interaction between the model and the system: during the build phase the model is placed on SpiNNaker; at runtime, placement information mediates communication with devices and instrumentation for data analysis. Integration within the computational neuroscience community is achieved by interfaces to two domain-specific languages: PyNN and Nengo. The real-time, event-driven nature of the SpiNNaker platform is explored using address-event representation sensors and robots, performing visual processing using a silicon retina, and navigation on a robotic platform based on a cortical, basal ganglia and hippocampal place cells model. The approach has been successfully exploited to run models on all iterations of SpiNNaker chips and development boards to date, and demonstrated live in workshops and conferences.

Orientador: Pedro Paulo Corbi / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-22T10:51:51Z (GMT). No. of bitstreams: 1 Bergamini_FernandoRodriguesGoulart_M.pdf: 3949422 bytes, checksum: a370801f06af8c8a41524fa60d90e776 (MD5) Previous issue date: 2013 / Resumo: Neste trabalho, são descritas a síntese e a caracterização de três complexos inéditos de prata com os ligantes L-butionina sulfoximina (BSO), ácido 2-tiazolidina carboxílico (2-TC) e ácido 4-tiazolidina carboxílico (4-TC). O complexo de prata com BSO foi caracterizado por um conjunto de análises químicas e espectroscópicas, a saber: análise elementar, análise térmica, espectroscopia na região do infravermelho (IV), espectroscopia Raman, espectroscopia de ressonância magnética no estado sólido de C (C-RMN), estudos por DFT e ensaios biológicos. Os complexos de prata(I) com 2-TC e 4-TC, por sua vez, foram caracterizados por análise elementar, análise térmica, espectroscopia na região do infravermelho (IV), espectroscopia de ressonância magnética no estado sólido de C-RMN e N-RMN, estudos por DFT e ensaios biológicos. O complexo de prata com BSO, [Ag2(BSO)], apresenta uma composição 2:1 metal/ligante, sendo que a coordenação do ligante a um dos átomos de prata ocorre através dos grupamentos amino e carboxilato, enquanto que a coordenação ao segundo átomo de prata ocorre através do nitrogênio da sulfoximina. Os complexos de prata com 2-TC e 4-TC também apresentam proporção 2:1 metal/ligante, com um átomo de prata coordenado através do nitrogênio e o segundo átomo de prata coordenado através do carboxilato. As análises biológicas revelaram que os complexos [Ag2(BSO)], [Ag2(2-TC)] e [Ag2(4-TC)] são efetivos sobre cepas patogênicas Gram-positivas de Staphylococcus aureus, e cepas Gram-negativas de Escherichia coli e Pseudomonas aeruginosa / Abstract: This work deals with the synthesis and characterization of three new silver(I) complexes with the ligands Lbuthionine sulfoximine (BSO), thiazolidine-2 carboxylic acid (2-TC) and thiazolidine-4 carboxylic acid (4-TC). The silver complex with BSO was characterized by elemental and thermal analyses, infrared and Raman spectroscopies, C nuclear magnetic resonance in the solid-state (C-NMR), DFT studies and biological assays. The silver(I) complexes with 2-TC and 4-TC were characterized by elemental and thermal analyses, infrared spectroscopy, C and N nuclear magnetic resonance in the solid-state, DFT studies and biological assays. The silver-BSO complex, [Ag2(BSO)], presents a 2:1 metal/ligand ratio. One of the silver(I) ion was shown to be coordinated through the amine nitrogen atom and the oxygen of carboxylate, while the second ion was shown to be coordinated through the nitrogen atom of the sulfoximine group. The silver(I) complexes with 2-TC and 4-TC also presented a 2:1 metal/ligand ratio, and are coordinated by the nitrogen and the oxygen atom of the carboxylate group. The biological assays revealed that the [Ag2(BSO)], [Ag2(2-TC)] and [Ag2(4-TC)] complexes are active against Gram-positive pathogenic strains of Staphylococcus aureus and Gramnegative pathogenic strains of Escherichia coli and Pseudomonas aeruginosa / Mestrado / Quimica Inorganica / Mestre em Química

<p>Cyclobutane pyrimidine dimers (CPD) are the predominant DNA lesions formed upon exposure of this biopolymer to sunlight. Given the potentially dire biological consequences of DNA lesions, there is a need to fully characterize their behaviour, with an eye towards understanding their complete reactivity and as a possible means to detect and quantify their presence in the genome. The work described in this dissertation describes studies of the alkaline reactivity of CPD lesions generated within dinucleotide & polynucleotide strands. It was found that CPD-TpT is generally inert under alkaline conditions at room temperature, which is in agreement with earlier studies on alkaline hydrolysis of CPD-thymine and CPD-thymidine. However, a re-evaluation of the same reaction in the presence of ¹⁸O labelled water demonstrated that, similar to other UV-induced DNA lesions containing a saturated pyrimidine ring, CPD undergoes a water addition at the C4=O group of the nucleobase leading to the formation of a hemiaminal intermediate. This intermediate, however, does not lead to hydrolysis products and completely reverts to starting material under those same conditions. Moreover, the two C4=O groups present on 3′ and 5′-thymines in a CPD molecule show different chemical reactivities, with the 3′ C4=O group having greater affinity towards water addition as compared to the one on 5′ end, a fact reflected in different rates of exchange with the incoming nucleophile leading to the hemiaminal intermediate. The ¹⁸O labelling reaction was also investigated in CPD lesions generated within oligonucleotides to probe the cause of asymmetry between the 3′ <i>vs</i> 5′ C4=O groups; ultimately, it was determined that the asymmetric reactivity observed to occur between the two C4=O groups was an intrinsic property of the CPD molecule and did not arise as a result of asymmetry in a dinucleotide setting.</p><p><br></p> <p>In addition to the above studies, during the course of the investigation of the nucleophilic reactivity of CPD, a chemical reaction was observed leading to what appeared to be the rapid and total chemical reversal of CPD lesions to the original TpT (thymine-thymine dinucleotide)! This “repair” reaction occurred when CPD reacted with hydrazine, and appears facilitated by an inert atmosphere under which it rapidly proceeds to completion at room temperature.</p><br>

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23505号 / 工博第4917号 / 新制||工||1768(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 松野 文俊, 教授 泉田 啓, 教授 小森 雅晴 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This thesis deals with efficiency of colostrum contained in cosmetics. The aim of study was to determine whether the colostrum contained in cosmetic preparations have any influence on the state of human skin. The theoretical part is a literary review and it deals with defining the basic concepts and phenomena, especially the colostrum, its composition and properties. There is also discussed the raw materials used for real samples preparation and efficiency evaluated on these samples. There are also described the methods used to evaluate cosmetic products. The practical part is focused on evaluating the influence of hydratation of prepared cosmetic products. The skin hydratation and transepidermal water loss was measured by MPA 5. Consumer tests are attached to this part. Chemical stability of these cosmetics is assessed in a special chapter.

This thesis deals with biologically-inspired interactive neural networks for the task of object recognition. Such networks offer an interesting alternative approach to traditional image processing techniques. Although the networks are very powerful classification tools, they are difficult to handle due to their bidirectional interactivity. It is one of the main reasons why these networks do not perform the task of generalization to novel objects well. Generalization is a very important property for any object recognition system, as it is impractical for a system to learn all instances of an object class before classifying. In this thesis, we have investigated the working of an interactive neural network by fine tuning different structural and algorithmic parameters.  The performance of the networks was evaluated by analyzing the generalization ability of the trained network to novel objects. Furthermore, the interactivity of the network was utilized to simulate focus of attention during object classification. Selective attention is an important visual mechanism for object recognition and provides an efficient way of using the limited computational resources of the human visual system. Unlike most previous work in the field of image processing, in this thesis attention is considered as an integral part of object processing. Attention focus, in this work, is computed within the same network and in parallel with object recognition. As a first step, a study into the efficacy of Hebbian learning as a feature extraction method was conducted. In a second study, the receptive field size in the network, which controls the size of the extracted features as well as the number of layers in the network, was varied and analyzed to find its effect on generalization. In a continuation study, a comparison was made between learnt (Hebbian learning) and hard coded feature detectors. In the last study, attention focus was computed using interaction between bottom-up and top-down activation flow with the aim to handle multiple objects in the visual scene. On the basis of the results and analysis of our simulations we have found that the generalization performance of the bidirectional hierarchical network improves with the addition of a small amount of Hebbian learning to an otherwise error-driven learning. We also conclude that the optimal size of the receptive fields in our network depends on the object of interest in the image. Moreover, each receptive field must contain some part of the object in the input image. We have also found that networks using hard coded feature extraction perform better than the networks that use Hebbian learning for developing feature detectors. In the last study, we have successfully demonstrated the emergence of visual attention within an interactive network that handles more than one object in the input field. Our simulations demonstrate how bidirectional interactivity directs attention focus towards the required object by using both bottom-up and top-down effects. In general, the findings of this thesis will increase understanding about the working of biologically-inspired interactive networks. Specifically, the studied effects of the structural and algorithmic parameters that are critical for the generalization property will help develop these and similar networks and lead to improved performance on object recognition tasks. The results from the attention simulations can be used to increase the ability of networks to deal with multiple objects in an efficient and effective manner.

In recent years there has been significant research in the field of computational neuroscience and many of these biologically inspired cognitive models are based on the theory of operation of mammalian visual cortex. One such model of neocortex developed by George & Hawkins, known as Hierarchical Temporal Memories (HTM), is considered for the research discussed here. We propose a simple hierarchical model that is derived from HTM. The aim of this work is to evaluate the hardware cost and performance against software based simulations. This work presents a detailed hardware implementation and analysis of the derived hierarchical model. We show that these networks are inherently parallel in their architecture, similar to the biological computing, and that parallelism can be exploited by massively parallel architectures implemented using reconfigurable devices such as the FPGA. Hardware implementation accelerates the learning process which is useful in many real world problems. We have implemented a complex network node that operates in real time using an FPGA. The current architecture is modular and allows us to estimate the hardware resources and computational units required to realize large scale networks in the future.

<p> The study of proteasome is a rapidly evolving field with multifaceted implications in neuroscience, aging, and cancer. Recent developments structural biology of the proteasome machinery has catapulted the drug discovery and targeted protein degradation. The success of proteasome inhibitors like Bortezomib and Ixazomib has also led to new interests in developing more precise inhibitors for the various proteasome isoforms. Proteasome activation is a relatively new field, and much has to be done in the field. The 20S CP is an emerging target in chemical biology and drug discovery for its implications in maintaining protein homeostasis and immune regulation. The central theme of the thesis is to study the proteasome in cellular contexts to develop new chemical biology tools to study the proteasome and its modulation by small molecules and probes in cellular contexts to ameliorate protein accumulation-mediated neurodegeneration </p>