Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-04-25T23:51:26Z No. of bitstreams: 1 TabataLoiseCunhaLima_DISSERT.pdf: 1403767 bytes, checksum: 7424c70f286f04743b45ac7531e6829b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-04-28T20:23:59Z (GMT) No. of bitstreams: 1 TabataLoiseCunhaLima_DISSERT.pdf: 1403767 bytes, checksum: 7424c70f286f04743b45ac7531e6829b (MD5) / Made available in DSpace on 2016-04-28T20:23:59Z (GMT). No. of bitstreams: 1 TabataLoiseCunhaLima_DISSERT.pdf: 1403767 bytes, checksum: 7424c70f286f04743b45ac7531e6829b (MD5) Previous issue date: 2015-03-13 / A dengue ? uma doen?a de notifica??o compuls?ria e cerca de 50 a 100 milh?es de casos s?o registrados anualmente. Possui amplo espectro cl?nico e ? transmitida ao homem atrav?s da picada dos mosquitos do g?nero Aedes, tendo como principal vetor a esp?cie Aedes aegypti. O agente etiol?gico da doen?a ? o v?rus dengue (DENV) pertencente ao g?nero Flavivirus, fam?lia Flaviviridae e s?o conhecidos quatro sorotipos antigenicamente distintos (DENV-1, DENV-2, DENV-3 e DENV-4). Atualmente o tratamento da dengue ? apenas de suporte, feito atrav?s de intensa hidrata??o. Ainda n?o existe uma vacina comprovadamente eficaz ou tratamento espec?fico, o estudo de poss?veis antivirais que possam diminuir a viremia no paciente ? de alt?ssima relev?ncia, uma vez que a carga viral ? um dos fatores associado ao aparecimento das formas graves da doen?a (febre hemorr?gica da dengue e s?ndrome do choque da dengue). No presente estudo n?s avaliamos o potencial antiviral de extratos brutos obtidos a partir das folhas das plantas do Nordeste brasileiro Annona muricata (graviola) e Spondias mombin (caj?) contra o DENV-2 em cultura de c?lulas C6/36 e Vero. A avalia??o da a??o dos extratos brutos foi feita por meio da quantifica??o da carga viral atrav?s da PCR em Tempo Real (qRT-PCR) e pela t?cnica de contagem de unidades formadoras de placa (PFU). As concentra??es dos extratos de ambas as plantas utilizadas foram: 0,01, 0,1 e 1mg/mL. As culturas de c?lulas infectadas foram submetidas ao tratamento com os extratos durante os per?odos de 24-168h horas (7 dias). C?lulas Vero tratadas com o extrato da S. mombin n?o apresentaram redu??o na carga viral. Em contrapartida, quando estas c?lulas foram tratadas com o extrato da A. muricata, uma hora ap?s infec??o, observou-se uma redu??o significativa na carga viral nas primeiras horas (24h), quando comparadas com as c?lulas n?o tratadas utilizadas como controle positivo. Ao serem tratadas em intervalos de 24 horas apresentaram uma redu??o na carga viral nos dias subsequentes (at? o s?timo dia). N?o foi observada redu??o na carga viral em c?lulas C6/36 tratadas com ambos os extratos. De acordo com os nossos resultados, o extrato da planta A. muricata possui potencial antiviral promissor contra a infec??o pelo DENV-2 em cultura de c?lulas Vero. / Dengue is a reportable disease and about 50 to 100 million cases are reported annually. It has a wide clinical spectrum and is transmitted to humans through the bite of Aedes mosquitos, the main vector the Aedes aegypti species. The causative agent of disease is dengue virus (DENV) belonging to the genus Flavivirus, family Flaviviridae and are known four antigenically distinct serotypes (DENV-1, DENV-2, DENV-3 and DENV-4). Currently the treatment of dengue is supportive, made by intense hydration. Although there is no proven effective vaccine or specific treatment, the study of potential antiviral drugs that can reduce viremia in patients is very high importance, since the viral load is one of the factors associated with the development of severe forms of the disease (hemorrhagic fever dengue and dengue shock syndrome). In the present study we evaluated the antiviral potential of crude extracts obtained from the leaves of plants in Northeastern Brazil Annona muricata (soursop) and Spondias mombin (caja) against DENV-2 in cultured C6/36 and Vero. The evaluation of the activity of the crude extracts was performed by the quantification of viral load by RT-PCR (qRT-PCR) and counting technique of plaque forming units (PFU). The concentrations of extracts of both plants used were 0.01, 0.1 and 1 mg/mL. The infected cell cultures were subjected to treatment with the extracts during periods of 24-168h hours (7 days). Vero cells treated with the S. mombin extract showed no reduction in viral load. In contrast, when these cells were treated with the extract of A. muricata, one hour after infection, significant reductions in viral load in the first hour was observed (24 h) when compared to untreated cells used as positive control. When they are treated at 24 hour intervals showed a reduction in viral load in subsequent days (until day). There was no reduction in viral load in C6/36 cells treated with both extracts. According to our results, the plant extract has antiviral A. muricata promising potential against infection by DENV-2 in Vero cell culture.

The individual behaviour of prokaryotic organisms such as bacteria often gives rise to complexity that is commonly associated with multicellular behaviour. The transition from unicellular to multicellular behaviour occurs in response to chemical signals, called autoinducers, which bacteria generate and receive internally within a given population. These autoinducers control the gene expression necessary for the emergence of group-behaviour-phenotype. This phenomenon is called quorum sensing (QS). An example of the quorum sensing control of gene regulation has been the luminescence (lux) operon in Vibrio fischeri. The luxI and ainS quorum signalling systems work in conjunction to regulate luminescence in V. fischeri. LuxI and AinS are acyl-synthases that catalyse the production of the autoinducers C6-HSL and C8-HSL respectively. These autoinducers bind to LuxR, a transcriptional activator of the lux operon, which activates expression of the lux genes causing an increase in luminescence. It was shown that quorum signalling also affects motility and biofilm formation in bacteria. However, the evidence with respect to these phenotypes is conflicting and inconclusive, the reason being the state of quorum is ambiguously defined. It is not properly known whether the observed collective behaviour is purely a result of physical crowding of bacteria, or that both chemical signalling and crowding contribute to this phenomenon. This work attempts to address these issues by studying luminescence, motility, and biofilm, a diverse set of behaviours, yet closely linked to each other in V. fischeri-squid symbiosis. We studied the luminescence response of V. fischeri to both endogenous and externally added signals at per-cell and population level. Experiments with ES114, a wild-type strain of V. fischeri, and ainS mutant showed that (i) luminescence per cell does not mutually correlate with the cell-density, indicating that bacteria do not show greater response to the signal at higher densities; (ii) the activity of the lux signalling circuit shows a strong dependence on the growth stage, (iii) the cells do not show enhanced growth, i.e., they do not derive fitness benefits at higher densities in response to the signal. We anticipated that the culture with a higher cell-density should exhibit greater per-cell-luminescence. However, we found that the luminescence curve of the culture with lower density crosses that of the cultures with higher densities during the exponential phase. Kinetic modelling of the luxI mRNA expression showed that the expression profile qualitatively agrees with the luminescence trend observed in the cultures, supporting the observation that growth-phase plays a major role in regulating the luminescence gene expression. We also studied the effect of autoinducers on motility of V. fischeri. V. fischeri uses flagella to move into the inner crypts of the light organ of the squid. The bacterium secretes autoinducers, encounters secretions of the light organ, and slows down during the final stage of colonization process. Studies have shown that flagellar elaboration is repressed as a consequence of ainS signalling. However, those studies were soft-agar migration assays and carried out with the mutant strain of ainS. We measured real-time planktonic motility of ES114 and the signalling mutant strains of V. fischeri in response to autoinducers added exogenously at different concentrations. We found that the autoinducers do not affect the motility of the strains. We also showed that reduction in motility is purely a consequence of physical crowding of bacteria, and chemical signalling may not be involved in the process. It was shown that reduction in motility leads to biofilm formation. Motile bacteria must lose flagella in order to form biofilm, and signalling controls biofilm formation in many species. Our study on motility showed that reduction in motility occurs because of physical crowding in V. fischeri. Hence, we explored the possibility that physical crowding might lead to formation of biofilm rather than signalling in this species. We quantified exopolysaccharide production by crystal violet assay, which revealed that planktonic cells produce exopolysaccharides, in addition to biofilm cells. The study revealed that V. fischeri cells always produce exopolysaccharides irrespective of their physiological state. We examined the effect of signalling on biofilm in ES114 and the mutant strains using gene-expression analysis. We quantified the expression of various genes involved in biofilm formation and found that both ES114 and the mutants expressed rscS and sypP indicating that exopolysaccharide production is not under the control of autoinducers. Therefore, we hypothesized that biofilm formation in V. fischeri may be a result of physical agglomeration of cells. Our observations indicate that the state of quorum is inadequately defined and there is no direct measure of the underlying process. Multicellular behaviour in V. fischeri is regulated by a complex interplay of cell-density, signalling, and other factors such as the growth phase of the culture, indicating that the state of quorum employs different mechanisms to regulate various phenotypes. Our study reveals that QS is an intricate process, and the accepted mechanisms for QS are incomplete at best.

For the astrophysically relevant molecules, C3 and C6, ab initio calculations are performed to study the geometries of different neutral isomers, the electronic structures of C3 in its ground and excited states, and possible pathways for the reaction C3 + C3 = C6. For C3 we present calculations for the potential energy surfaces of C3 in different electronic configurations, including the singlet ground state, the triplet ground state, and some higher excited states. The geometries studied include triangular shapes with two identical bond lengths, but different bond angles between them. For the singlet and triplet ground states in the linear geometry, the total energies resulting from the mixed density functional-Hartree-Fock and quadratic configuration interaction methods reproduce the experimental values, i.e. the triplet occurs 2.1 eV above the singlet. In the geometry of an equilateral triangle, we find a low-lying triplet state with an energy of only 0.8 eV above the energy of the singlet in the linear configuration, so that the triangular geometry yields the lowest excited state of C3. For the higher excited states up to about 12 eV above the ground state, we apply time-dependent density functional theory. Even though the systematic error produced by this approach is of the order of 0.4 eV, the results give new insight into the potential energy landscape for higher excitation energies. For C6 we consider the known linear states and the lowest state of monocyclic ring. The potential energy surfaces, were built for various pathways for the reaction C3 + C3 = C6. For this investigation we apply a mixed density functional-Hartree-Fock method which gives good results with respect to the experimental values and does not demand much computational time. We have considered collinear and symmetric non-linear as well as some non-symmetric collision schemes of two C3 subunits, producing the 1Ag states of a D2h isomer, one in a cyclic shape, the other in the form of two triangles connected by the corners, and for the non-symmetric scheme the 1A' state of a Cs isomer. To investigate the pathways for the creation of C6 from two C3 we emphasize the importance of the electron configuration for the reacting C3 subunits. As a result we have obtained the following rule: The stable linear as well as the cyclic C6 molecule can only be created in the case when at least one C3 has a partially filled orbital, requiring an excited state with respect to the singlet ground state of C3. / Für die astrophysikalisch bedeutenden Moleküle C3 und C6 werden ab initio Berechnungen von elektronischen Zuständen verschiedener Isomere durchgeführt. Basierend auf der Optimierung verschiedener neutraler Isomere von C3 im Grundzustand und mehreren angeregten Zuständen werden mögliche Wege für die Reaktion C3 + C3 = C6 studiert. Für C3 werden ab initio Berechnungen für die Flächen der potentiellen Energie in verschiedenen elektronischen Konfigurationen durchgeführt, einschließlich des Singulett-Grundzustands, des Triplett-Grundzustands, und einiger höherer Anregungszustände. Die untersuchten Geometrien schließen gleichschenklige Dreiecke mit zwei identischen Bindungslängen ein, wobei der Bindungswinkel dazwischen variiert wird. Die Gesamtenergien, die sich in einem gemischten Hartree-Fock-Dichtefunktional-Verfahren und unter Verwendung der quadratischen Konfigurationswechselwirkung ergeben, reproduzieren die experimentell beobachtete Energiedifferenz von 2.1 eV zwischen dem niedrigsten Triplett-Zustand und dem Singulett-Grundzustand. In der Geometrie des gleichseitigen Dreiecks ergibt sich ein niedrigerliegender Triplett-Zustand mit einer Energie von nur 0.8 eV über der Energie des Singuletts im linearen Isomer, so dass die dreieckige Geometrie den niedrigsten Anregungszustand von C3 ergibt. Für höhere Anregungsenergien bis zu 12 eV über dem Grundzustand wird zeitabhängige Dichtefunktional-Theorie zur Ermittlung der Energie angeregter elektronischer Konfigurationen eingesetzt. Obwohl der von dieser Methode produzierte systematische Fehler von der Größenordnung von 0.4 eV ist, ergeben sich interessante neue Einblicke in die Potentiallandschaft angeregter Zustände. Für C6 betrachten wir das bekannte lineare Isomer und das zyklische Isomer. Der Verlauf der Potentialoberflächen wird für verschiedene Reaktionspfade C3+C3 = C6 untersucht, wobei ein gemischtes Hartree-Fock-Dichtefunktional-Verfahren einesetzt wird. Im Mittelpunkt des Interesses stehen dabei kollineare Anordnungen linearer C3 Moleküle, symmetrische Kollisionen nichtlinearer Reaktanden, sowie einige nichtsymmetrische koplanare Geometrien des Zusammenstosses zweier linearer Moleküle. Als Ergebnis der Reaktionen mit symmetrischen Anordnungen ergibt sich lineares C6 oder zyklisches C6 mit D2h Symmetrie in einem elektronischen Zustand der höchsten Symmetrie 1Ag. Das nicht-symmetrische Reaktionsschema führt zu einem planaren Isomer Cs im Zustand 1A'. Um die Wege für die Bildung von C6 aus zwei C3 zu untersuchen, ist die elektronische Konfiguration der Reaktanden von entscheidender Bedeutung. Als Ergebnis erhält man die folgende Regel: sowohl ein stabiles lineares als auch ein zyklisches C6 Molekül können nur gebildet werden, wenn zumindest eines der C3 Moleküle ein teilweise gefülltes Orbital hat, wofür eine Anregung aus dem Singulett-Grundzustand heraus erforderlich ist.

233 U est le noyau fissile produit dans le cycle du combustible 232 T h/233 U qui a été proposé comme une alternative plus sûre et plus propre du cycle 238 U/239 P u. La connaissance précise de la section efficace de capture de neutrons de cet isotope est requise avec une haute précision pour la conception et le développement de réacteurs utilisant ce cycle du combustible. Les deux seuls jeux de données expérimentales fiables pour la section efficace de capture de l’233 U montrent des écarts important allant jusqu’à 20%. Ces différences peuvent être dues à desincertitudes systématiques associées à l'efficacité du détecteur, la correction du temps mort, la soustraction du bruit de fond et le phénomène d’empilement de signaux causé par la forteactivité α de l’échantillon. Un dispositif expérimental dédié a la mesure simultanée des sections efficaces de fission et de capture des noyaux fissiles radioactifs a été conçu, assemblé et optimiséau CENBG dans le cadre de ce travail. La mesure sera effectuée à l’installation de temps de vol de neutrons Gelina de l’IRMM, où les sections efficaces neutroniques peuvent être mesurées sur une large gamme d’énergie avec une haute résolution énergétique. Le détecteur de fission se compose d’une chambre à ionisation (CI) multi-plaque de haute efficacité. Les rayons γ produits dans les réactions de capture sont détectés par un ensemble de six scintillateurs C6 D6entourant la CI. Dans ces mesures, les rayons γ de la capture radiative sont masqués parle grand nombre de rayons γ de fission, ce qui représente le problème le plus délicat. Ces γ parasites doivent être soustraits par la détection des événements de fission avec une efficacité très bien connue (méthode de VETO). Une détermination précise de cette efficacité est assezdifficile. Dans ce travail, nous avons soigneusement étudié la méthode des neutrons prompts de fission pour la mesure de l'efficacité de la CI, apportant un éclairage nouveau sur la méthode, ce qui a permi d’obtenir une excellente précision sur l'efficacité de détection des fission d’une sourcede 252 Cf. Avec cette même source, plusieurs paramètres (pression du gaz, haute tension et la distance entre les électrodes) ont été étudiés afin de déterminer le comportement de la CI et detrouver le point de fonctionnement idéal : une bonne séparation énergétique entre les particulesα et les fragments de fission (FF) et une bonne résolution temporelle. Une bonne séparationα-FF a également été obtenue avec une cible d’233 U très radioactive. De plus, l’analyse deforme de signaux entre les rayons γ et les neutrons dans les détecteurs C6 D6 a été observée àGelina dans des conditions expérimentales réalistes. Pour conclure, le dispositif expérimentalet la méthode de VETO ont été soigneusement vérifiés et validés, ouvrant la voie à la mesure future des sections efficaces de capture et fission d’233 U . / 233U is the fissile nucleus produced in 232T h/233U fuel cycle which has been proposed as asafer and cleaner alternative to the 238U/239P u cycle. The accurate knowledge of the neutroncapture cross-section of this isotope is needed with high-precision for design and developmentof this fuel cycle. The only two reliable experimental data for the capture cross-section of233U show discrepancies up to 10%. These differences may be due to systematic uncertaintiesassociated with the detector efficiency, dead-time effects, background subtraction and signalpile-up caused by the α-activity of the sample. A special experimental set-up for simultaneousmeasurement of fission and capture cross sections of radioactive fissile nuclei was designed,assembled and optimized at CENBG in the frame of this work. The measurement will be per-formed at the Gelina neutron time-of-flight facility at IRMM, where neutron cross sectionscan be measured over a wide energy range with high energy resolution. The fission detectorconsists of a multi-plate high-efficiency ionization chamber (IC). The γ-rays produced in cap-ture reactions are detected by an array of six C6 D6 scintillators surrounding the IC. In thesemeasurements the radiative capture γ-rays are hidden in large background of fission γ-rays thatrepresents a challenging issue. The latter has then to be subtracted by detecting fission eventswith a very well known efficiency (VETO method). An accurate determination of this efficiencyis rather difficult. In this work we have thoroughly investigated the prompt-fission-neutronsmethod for the IC efficiency measurement, providing new insights on this method. Thanks tothis study the IC efficiency was determined with a very low uncertainty. Using a 252Cf source,several parameters (gas pressure, high voltage and the distance between the electrodes) havebeen studied to determine the behaviour of the IC in order to find the ideal operation point:a good energy separation between α-particles and fission fragments (FF) and a good timingresolution. A good α-FF separation has been obtained with a highly radioactive 233U target.Also, the pulse-shape discrimination between γ-rays and neutrons in the C6D6 detectors wasobserved at Gelina under realistic experimental conditions. To conclude, the experimentalset-up and the VETO method have been carefully checked and validated, opening the way tofuture measurements of the capture and fission cross sections of 233U.

Following the debate by empirical finance research on the presence of non-linear predictability in stock market returns, this study examines forecasting abilities of nonlinear STAR-type models. A non-linear model methodology is applied to daily returns of FTSE, S&P, DAX and Nikkei indices. The research is then extended to long-horizon forecastability of the four series including monthly returns and a buy-and-sell strategy for a three, six and twelve month holding period using non-linear error-correction framework. The recursive out-of-sample forecast is performed using the present value model equilibrium methodology, whereby stock returns are forecasted using macroeconomic variables, in particular the dividend yield and price-earnings ratio. The forecasting exercise revealed the presence of non-linear predictability for all data periods considered, and confirmed an improvement of predictability for long-horizon data. Finally, the present value model approach is applied to the housing market, whereby the house price returns are forecasted using a price-earnings ratio as a measure of fundamental levels of prices. Findings revealed that the UK housing market appears to be characterised with asymmetric non-linear dynamics, and a clear preference for the asymmetric ESTAR model in terms of forecasting accuracy.

This is a qualitative research project conducted on children in institutional care who have incarcerated parent(s) in China with the purpose of exploring the subjective living experiences and self-identity of these children. A homogeneous sample of seventeen children in institutional care who have incarcerated parents, a sample of seven institutional staff, three school teachers, and four family members who were these children’s previous caregivers, were included according to purposive sampling procedures. This study employed narrative analysis as the method used to analyze the data collected through semi-structured in-depth interviews. / With the assumption that identity formation is a process of social construction, the study proposes a theoretical framework consisting of Chinese social and cultural contexts, the family, the societal context, and the children’s subjective experience and identity. This comes after a comprehensive review of the literature on empirical services, polices, and research on children with incarnated parents, theories concerning identity and identity development, and the dominant ideologies about incarceration in the Chinese context. / This study finds that parental incarceration eventually changes these children’s lives so that they suffer helplessness, abandonment and uncertainty. Grateful feelings emerge when they enter a charitable institution that provides them with a relatively stable and secure living environment. There children are referred to or refer to themselves as “children of the institution”. This public label covers their status as inferior, as service recipients of an institution, and the misunderstood status of “orphan. These children develop paradoxical feelings towards these different labels and their self-identity is actually incarcerated in the parent-child relationship along with the incarcerated parents. The internalized ignominy of being children of incarcerated parents further enhances their feeling of inferiority as service recipients of an institution. / To understand the self-identity of these institutionally reared children with incarcerated parents (CIP), as well as its formation process in the Chinese socio-cultural context, the study develops a model that includes elements such as the Chinese moral censure of criminals, familial belief, and the individual-familial responsibility and the concept of “Bao”. These three ideas not only directly impact these children’s self-identity, but also comprise the basis for discourses in the three sub-contexts in which these children derive their living experiences and develop their self-identities. These socio-cultural beliefs are generally held by actors in various situations, and cultural messages are conveyed to these children by those actors through interaction with the children, and these cultural messages shaped the children’s’ subjective experiences and identities. / Based on the findings of this research, the researcher proposes suggestions for social works services for children with incarcerated parents from both micro and macro perspectives, and suggests directions for future research. / 置身中國社會文化語境、以建構主義為理論嚮導，本是一項探索機構照料的服刑人員子女的主觀生活經驗和身份認同及其形成過程為目敘事研究。通對以往服刑人員子女相關務與研究、身份認同理論以及中國社會於"服刑"的敘說進行較為全面回顧與梳理，研究者提出一個囊括中國文化、家庭、社會語境、機構環境及服刑人員子女主觀經驗的互動過程框架用以指導研究。該研究採用目的抽樣，從中國大陸某專門資助、代養服刑人員未成年子女的民間慈善機構選取符合條件的17名服刑人員子女 、7名機構工作人員 、3名學校老師和4名兒童親屬。 通過半結構化的深入訪談收集資料，使用 Nvivo 軟件對訪談資料進行細緻編碼，最後總結顯著主題并撰寫報告。 / 該研究發現，父母服刑給其子女帶來諸多負面後果。被訪兒童在父母服刑后都經歷生活困難、無助與被拋棄，由此產不安全感。入住該機構，他們遇上相對穩定全的生活，也自賦或被予一個“公共身份” —— 機構的孩子。對這一身份他們有著複雜而糾結的情感，一方面這身份昭示其作為服務受助者低人一等并隱含被誤解為“孤兒”的尷尬；另一方面，這公共身份也像個保護傘，使其"服刑人員子女”這一身份在某種程度上得以掩蓋。他們都強烈感知并內化作為服刑子女的羞恥以及作為服務受助者的低人一等。從此意義而言，他們自我被禁錮其中。 / 文章最後得出包含社會化因素、主流言論、家庭、機構以及服刑人員子女等因素的多方互動模型用以呈現和解釋他們主觀生活經驗與自我身份認同及其形成過程。中國社會三個主要觀點 —— 對罪犯的道德譴責、家庭主義和個人、家庭主義和個人 -家庭負責的福利理念、報 —— 相互作用，共同造就社會主流論述對服刑人員子女的歧視、 家庭成員的羞恥感以及機構中對於恩回報期待；進而，服刑人子女通過與這三個系統中的人進行互動，也感知和內化對他們負面看法，形塑主觀經驗和身份認同。 / 基於這些發現，本文在最後就服刑人員子女社會服務改善提出建議，認為微觀層面，機構應該改變服務理念；而在宏觀層面，政府應該介入，且整個社會文化的導向也應該有所調整。本文最后指出未來研究的可能方向。 / Xia, Lili. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 269-296). / Abstracts and appendixes also in Chinese. / Title from PDF title page (viewed on 20, December, 2016). / Xia, Lili. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

One of the most devastating effects of tetraplegia is the inability to grasp and manipulate everyday objects necessary to living an independent life. Currently surgery is widely accepted as the solution to improve hand functionality. However, surgery becomes difficult when the user has paralysed wrists as is the case with C5 tetraplegia. The aim of this research was to develop a solution which provided controlled wrist flexion and extension which, when combined with surgery, achieves a 'key pinch' grip. This particular grip is critically important for people with C5 tetraplegia as it is used for countless grasping activities, necessary on a day-to-day basis. A systematic design process was used to evolve the solution to provide controlled wrist flexion and extension. Concept brainstorming identified four alternative solutions which were evaluated to find the preferred concept. The chosen solution was called the Self Powered Wrist Extension Orthosis, more commonly referred to as the 'orthosis'. This concept contained a shoulder harness which provided both energy and control to the wrist harness, which in turn changed the wrist position. The orthosis was developed with the use of a mathematical model which theoretically predicted the functional performance by comparing the required force needed to move the wrist harness to the achievable force supplied by the user's shoulders. Using these parameters, the orthosis was optimized using the matlab Nelder-Mead algorithm which adjusted the wrist harness geometries to maximize the functional performance. A prototype was constructed and tested with the help of two participants who when combined, achieved an average of 18.5° of wrist rotation. The theoretical model however predicted an average range of motion of 28.4°. The discrepancy found between the theoretical and experimental result can be contributed to incorrect assumptions in the theoretical model. This included unaccounted friction and inaccurate modeling of the orthosis dynamics. The feedback from potential users of the orthosis was enthusiastic and encouraging especially towards the simplicity, usability and practicality of the design.

No description available.

233U is the fissile nucleus produced in 232T h/233U fuel cycle which has been proposed as asafer and cleaner alternative to the 238U/239P u cycle. The accurate knowledge of the neutroncapture cross-section of this isotope is needed with high-precision for design and developmentof this fuel cycle. The only two reliable experimental data for the capture cross-section of233U show discrepancies up to 10%. These differences may be due to systematic uncertaintiesassociated with the detector efficiency, dead-time effects, background subtraction and signalpile-up caused by the α-activity of the sample. A special experimental set-up for simultaneousmeasurement of fission and capture cross sections of radioactive fissile nuclei was designed,assembled and optimized at CENBG in the frame of this work. The measurement will be per-formed at the Gelina neutron time-of-flight facility at IRMM, where neutron cross sectionscan be measured over a wide energy range with high energy resolution. The fission detectorconsists of a multi-plate high-efficiency ionization chamber (IC). The γ-rays produced in cap-ture reactions are detected by an array of six C6 D6 scintillators surrounding the IC. In thesemeasurements the radiative capture γ-rays are hidden in large background of fission γ-rays thatrepresents a challenging issue. The latter has then to be subtracted by detecting fission eventswith a very well known efficiency (VETO method). An accurate determination of this efficiencyis rather difficult. In this work we have thoroughly investigated the prompt-fission-neutronsmethod for the IC efficiency measurement, providing new insights on this method. Thanks tothis study the IC efficiency was determined with a very low uncertainty. Using a 252Cf source,several parameters (gas pressure, high voltage and the distance between the electrodes) havebeen studied to determine the behaviour of the IC in order to find the ideal operation point:a good energy separation between α-particles and fission fragments (FF) and a good timingresolution. A good α-FF separation has been obtained with a highly radioactive 233U target.Also, the pulse-shape discrimination between γ-rays and neutrons in the C6D6 detectors wasobserved at Gelina under realistic experimental conditions. To conclude, the experimentalset-up and the VETO method have been carefully checked and validated, opening the way tofuture measurements of the capture and fission cross sections of 233U.

Modifying the metabolism of the body’s own endocannabinoids is a novel approach for analgesia. Two key catabolic enzymes are fatty acid amide hydrolase (FAAH) and inflammation-inducible cyclooxygenase 2 (COX-2). The cellular uptake of the key endocannabinoid anandamide (AEA) has been found to be regulated by its FAAH-catalysed intracellular degradation, but COX-2 has not been investigated in this respect. We aimed to find out whether or not COX-2 in an in vitro inflammation setting would be able to gate AEA uptake. To achieve this, C6 cells and Raw 264.7 cells were stimulated with LPS/INF-γ and lysates then analyzed by immunoblot in order to verify COX-2 expression. AEA cellular uptake was quantified using a radioassay with [3H]-AEA. It was found that COX-2 was not inducible in C6 cells using the LPS/INF-γ conditions studied, while it was inducible in Raw 264.7 cells. AEA uptake in the COX-2-induced Raw 264.7 cells was not reduced by inhibitors of this enzyme. FAAH appeared to be down-regulated in the stimulated Raw 264.7 cells, and this was reflected in an overall lower AEA uptake. Our interpretation of the data points to FAAH as gating AEA uptake. Additional experiments are required to validate our findings by verifying significance.