To see the other types of publications on this topic, follow the link: Bipolar model.
Dissertations / Theses on the topic 'Bipolar model'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Bipolar model.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Atkinson, Juan Pablo. "Cost model for bipolar plate manufacture." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71625.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2012.ENGLISH ABSTRACT: This thesis gives a cost model for the manufacture of bipolar plates in South Africa. The methods for the manufacture considered are machining, using a micro-milling machine, and compression moulding. The focus of this thesis is on compression moulding. Details of the work done towards developing and validating the models are described, and then the cost models are discussed in detail. The results of the analysis done using the cost model is given with attention paid to the effect of changing design parameters, such as channel size and flow field area, and of the cost of production for both methods over various production volumes. The thesis concludes that compression moulding becomes the better option for production volumes greater than 324 bipolar plates, with a cost that eventually reaches close to R140 per plate for high enough production volumes (over 5000). The cost to produce 1000 plates using compression moulding is estimated at R294 per plate. An increase of the channel size gives a small reduction in the total cost, while the increase in cost with an increase in flow field area is large.
AFRIKAANSE OPSOMMING: Hierdie tesis gee 'n koste-model vir die vervaardiging van bipolêre plate in Suid- Afrika. Die vervaardigingsmetodes wat oorweeg word, is masjinering deur 'n mikro-freesmasjien en persvorming. Die fokus van hierdie tesis is op persvorming. Die besonderhede van die ontwikkeling en validering van die modelle word beskryf, en daarna word die modelle in besonderhede beskryf. Die resultate van 'n analise wat met die koste-model gedoen is, word daarna gegee, met die oorweging van die verandering van ontwerp-parameters soos die vloeikanaalgrootte en vloeiveld-area, en van die koste van vervaardiging vir beide metodes vir verskeie produksievolumes. Die tesis kom tot die slotsom dat persvorming die voorkeurproses is vir produksievolumes groter as 324 bipolêre plate, met 'n koste wat tot naastenby R140 per plaat daal vir hoë produksievolumes (meer as 5000). Die koste om 1000 plate met persvorming te maak, word op R294 per plaat beraam. 'n Toename in kanaalgrootte gee 'n klein vermindering in die totale koste, terwyl die toename in koste groot is wanneer die vloeiveld-area toeneem.
2
Lamontagne, Maurice. "Development of a statistical model for NPN bipolar transistor mismatch." Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-053007-105648/.
Full text
3
Iyer, Indira G. "Implementation of bipolar transistor model in a waveform relaxation simulator." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1182437646.
Full text
4
Arreguit, Xavier. "Compatible lateral bipolar transistors in CMOS technology : model and applications /." [S.l.] : [s.n.], 1989. http://library.epfl.ch/theses/?nr=817.
Full text
5
Ghosh, Sudip. "Electronical model evaluation and development of compact model including aging for InP heterojunction bipolar transistors (HBTs)." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14451/document.
Full textAbstract:
Les technologies de transistors bipolaires à hétérojonctions (HBT) ont montré leur efficacité pour permettre aux circuits de traiter les grands signaux au delà de 100Gbit/s pour les réseaux optiques Ethernet. Pour assurer ce résultat, une bonne fiabilité doit être garantie. Des tests de vieillissements accélérés sous contraintes thermiques et électrothermiques sont réalisés et analysés avec les outils de simulation physique Sentaurus TCAD afin d’obtenir les lois de vieillissement physiques. Le modèle compact HICUM niveau 2, basé sur la physique, est utilisé pour modéliser précisément le composant avant vieillissement, puis pour ajuster les caractéristiques intermédiaires pendant le vieillissement. L’évolution des paramètres du modèle est décrit avec des équations appropriées pour obtenir un modèle électrique compact du vieillissement basé sur la physique. Les lois de vieillissement et les équations d’évolutions des paramètres avec le temps de contrainte sont implantées dans le modèle électrique de vieillissement en langage Verilog-A, ce qui permet de simuler l’impact des mécanismes de défaillances sur le circuit en conditions opérationnellesModern InP Heterojunction Bipolar Transistors (HBT) technology has shown its efficiency for making large signal ICs working above 100 Gbits/s for Ethernet optical transport network. To full-fill this expectation, a good reliability has to be assured. Accelerated aging tests under thermal and electro-thermal stress conditions are performed and analyzed with Sentaurus TCAD device simulation tools to achieve the physical aging laws. The physics based advanced bipolar compact model HICUM Level 2 is used for precise modeling of the devices before aging. The HICUM parameters are extracted to fit the intermediate characterizations during aging. The evolution of the model parameters is described with suitable equations to achieve a physics based compact electrical aging model. The aging laws and the parameter evolution equations with stress time are implemented in compact electrical aging model in Verilog-A languages which allows us to simulate the impact of device failure mechanisms on the circuit in operating conditions
6
Carroll, James M. "The psychometrics of a bipolar valence activation model of self-reported affect." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/NQ56520.pdf.
Full text
7
Essmann, Erich C. "A cost model for the manufacture of bipolar plates using micro milling." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20319.
Full textAbstract:
Thesis (MScEng)--Stellenbosch University, 2012.ENGLISH ABSTRACT: In a move towards cleaner and more sustainable energy systems, hydrogen as an energy carrier and hydrogen fuel cells as energy converters are receiving increasing global attention. Considering the vital role that platinum plays in the operation of hydrogen fuels cells, South Africa stands to gain enormously as the world’s leading platinum group metals supplier. Therefore, in order to benefit across the whole value chain, it is imperative to develop the capability to manufacture hydrogen fuel cell stacks locally. This project addresses this imperative, in part, by building a framework to evaluate the manufacturing performance of one of the more costly components of the hydrogen fuel cell stack. More specifically, this project builds a cost evaluation model (or cost model) for the manufacture of bipolar plates using micro milling. In essence, the model characterises manufacturing cost (and time) as a function of relevant inputs. The model endeavours to be flexible in accommodating relevant contributing cost drivers such as tool life and manufacturing time. Moreover, the model lays the groundwork, from a micro milling perspective, for a comparison of different manufacturing methods for bipolar plates. The approach taken in building the cost model is a fundamental one, owing to the lack of historical cost data for this particular process. As such, manufacturing knowledge and experimentation are used to build the cost model in a structured way. The process followed in building the cost model begins with the formulation of the cost components by reviewing relevant examples from literature. Thereafter, two main cost drivers are comprehensively addressed. Tool life is characterised experimentally as a function of cutting parameters and manufacturing time is characterised as a function of relevant inputs. The work is then synthesized into a coherent cost model. Following the completion of the cost model, analysis is done to find the near-optimal combination of machine cutting parameters. Further, analysis is done to quantify the sensitivity of manufacturing cost to design changes and production volumes. This attempts to demonstrate how typical managerial issues can be addressed using the cost model format. The value of this work must be seen in terms of its practical contribution. That is, its contribution to the development of the capability to manufacture hydrogen fuel cells locally. By understanding the effect of relevant input factors on manufacturing cost, ‘upstream’ design and development activities can be integrated with ‘downstream’ manufacturing activities. Therefore, this project supports the development of manufacturing capability by providing a mechanism to control cost throughout the process.
AFRIKAANSE OPSOMMING: In die soeke na skoner, meer volhoubare energie bronne word die fokus op waterstof, as energie draer, en waterstof brandstofselle, as energie omskakelaars, al meer verskerp. Deur die sleutelrol van platinum in die werking van waterstof brandstofselle in ag te neem, word Suid-Afrika, as die wêreld se grootste platinum verskaffer, in `n uitstekende posisie geplaas om voordeel te trek uit hierdie geleentheid. Om dus as land voordeel te trek uit die proses in geheel, is dit van kardinale belang om die vermoë te ontwikkel om waterstof brandstofsel stapels op eie bodem te vervaardig. Hierdie projek adresseer gedeeltelik hierdie noodsaaklikheid, deur `n raamwerk te bou wat die vervaardigingsoptrede van een van die meer duursame komponente van die waterstof brandstofsel stapel evalueer. Meer spesifiek, bou hierdie projek `n koste evaluerings model (of koste model) vir die vervaardiging van bipolêre plate deur die gebruik van mikro-masjienering. In wese kenmerk hierdie model vervaardigings kostes (en tyd) as `n funksie van relevante insette. Hierdie model poog om buigsaam te wees met die in ag neming van relevante bydraende kostedrywers soos buitelleeftyd en vervaardigingstyd. Daarbenewens lê hierdie model die grondwerk, vanuit `n mikro masjienerings oogpunt, vir die vergelyking van verskillende vervaardingings metodes vir bipolêre plate. Die benadering wat gevolg word in die bou van die koste model is fundamenteel as gevolg van die gebrek van historiese data vir hierdie spesifieke proses. As sodanig word vervaardigings kennis en eksperimentering gebruik om die koste model in `n gestruktueerde wyse te bou. Die proses gevolg in die bou van die koste model begin met die formulering van die koste komponente deur die hersiening van relevante voorbeelde vanuit die literatuur. Daarna word twee hoof koste drywers deeglik geadresseer. Buitelleeftyd word ekperimenteel gekenmerk as funksie van masjieneringsparameters en vervaardigingstyd word gekenmerk as `n funksie van relevante insette. Die werk word dan gesintetiseer in `n samehangende koste model. Wat volg op die voltooiing van die koste model is `n analise om die optimale kombinasie masjieneringsparameters te vind. Daaropvolgens word analises gedoen om die sensitiwiteit van vervaardigingskoste onderworpe aan ontwerpsveranderings en produksie volumes te kwantisfiseer. Dit poog om te demostreer hoe tipiese bestuursproblem geadresseer kan word deur die koste model formaat te gebruik. Die waarde van hierdie werk moet in die lig van die praktiese bydrae daarvan gesien word, menende, die bydrae tot die ontwikkeling van die vermoë om waterstof brandstofselle in Suid-Afrika te vervaardig. Deur die effek van relevante inset faktore op vervaardigingskoste te verstaan, kan ‘stroom-op’ ontwerp en ontwikkelings aktiwiteite geïntegreer word met ‘stroom-af’ vervaardigings aktiwiteite. Dus, hierdie projek ondersteun die ontwikkeling van vervaardigingsvermoëns deur `n meganisme te voorsien om kostes oor die omvang van die proses te beheer.
8
Linder, Martin. "DC Parameter Extraction and Modeling of Bipolar Transistors." Doctoral thesis, KTH, Microelectronics and Information Technology, IMIT, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3172.
Full text
9
Stein, Félix. "SPICE Modeling of TeraHertz Heterojunction bipolar transistors." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0281/document.
Full textAbstract:
Les études qui seront présentées dans le cadre de cette thèse portent sur le développement et l’optimisation des techniques pour la modélisation compacte des transistors bipolaires à hétérojonction (TBH). Ce type de modélisation est à la base du développement des bibliothèques de composants qu’utilisent les concepteurs lors de la phase de simulation des circuits intégrés. Le but d’une technologie BiCMOS est de pouvoir combiner deux procédés technologiques différents sur une seule et même puce. En plus de limiter le nombre de composants externes, cela permet également une meilleure gestion de la consommation dans les différents blocs digitaux, analogiques et RF. Les applications dites rapides peuvent ainsi profiter du meilleur des composants bipolaires et des transistors CMOS. Le défi est d’autant plus critique dans le cas des applications analogiques/RF puisqu’il est nécessaire de diminuer la puissance consommée tout en maintenant des fréquences de fonctionnement des transistors très élevées. Disposer de modèles compacts précis des transistors utilisés est donc primordial lors de la conception des circuits utilisés pour les applications analogiques et mixtes. Cette précision implique une étude sur un large domaine de tensions d’utilisation et de températures de fonctionnement. De plus, en allant vers des nœuds technologiques de plus en plus avancés, des nouveaux effets physiques se manifestent et doivent être pris en compte dans les équations du modèle. Les règles d’échelle des technologies plus matures doivent ainsi être réexaminées en se basant sur la physique du dispositif. Cette thèse a pour but d’évaluer la faisabilité d’une offre de modèle compact dédiée à la technologie avancée SiGe TBH de chez ST Microelectronics. Le modèle du transistor bipolaire SiGe TBH est présenté en se basant sur le modèle compact récent HICUMversion L2.3x. Grâce aux lois d’échelle introduites et basées sur le dessin même des dimensions du transistor, une simulation précise du comportement électrique et thermique a pu être démontrée.Ceci a été rendu possible grâce à l’utilisation et à l’amélioration des routines et méthodes d’extraction des paramètres du modèle. C’est particulièrement le cas pour la détermination des éléments parasites extrinsèques (résistances et capacités) ainsi que celle du transistor intrinsèque. Finalement, les différentes étapes d’extraction et les méthodes sont présentées, et ont été vérifiées par l’extraction de bibliothèques SPICE sur le TBH NPN Haute-Vitesse de la technologie BiCMOS avancée du noeud 55nm, avec des fréquences de fonctionnement atteignant 320/370GHz de fT = fmaxThe aim of BiCMOS technology is to combine two different process technologies intoa single chip, reducing the number of external components and optimizing power consumptionfor RF, analog and digital parts in one single package. Given the respectivestrengths of HBT and CMOS devices, especially high speed applications benefit fromadvanced BiCMOS processes, that integrate two different technologies.For analog mixed-signal RF and microwave circuitry, the push towards lower powerand higher speed imposes requirements and presents challenges not faced by digitalcircuit designs. Accurate compact device models, predicting device behaviour undera variety of bias as well as ambient temperatures, are crucial for the development oflarge scale circuits and create advanced designs with first-pass success.As technology advances, these models have to cover an increasing number of physicaleffects and model equations have to be continuously re-evaluated and adapted. Likewiseprocess scaling has to be verified and reflected by scaling laws, which are closelyrelated to device physics.This thesis examines the suitability of the model formulation for applicability to production-ready SiGe HBT processes. A derivation of the most recent model formulationimplemented in HICUM version L2.3x, is followed by simulation studies, whichconfirm their agreement with electrical characteristics of high-speed devices. Thefundamental geometry scaling laws, as implemented in the custom-developed modellibrary, are described in detail with a strong link to the specific device architecture.In order to correctly determine the respective model parameters, newly developed andexisting extraction routines have been exercised with recent HBT technology generationsand benchmarked by means of numerical device simulation, where applicable.Especially the extraction of extrinsic elements such as series resistances and parasiticcapacitances were improved along with the substrate network.The extraction steps and methods required to obtain a fully scalable model library wereexercised and presented using measured data from a recent industry-leading 55nmSiGe BiCMOS process, reaching switching speeds in excess of 300GHz. Finally theextracted model card was verified for the respective technology
10
Sarkar, Manju. "Lambda Bipolar Transistor (LBT) in Static Random Access Memory Cell." Thesis, Indian Institute of Science, 1995. https://etd.iisc.ac.in/handle/2005/124.
Full textAbstract:
With a view to reduce the number of components in a Static Random Access Memory (SRAM) cell, the feasibility of use of Lambda Bipolar Transistor (LBT)in the bistable element of the cell has been explored under the present study. The LBT under consideration here comprises of an enhancement mode MOSFET integrated with a parasitic bipolar transistor so as to perform as a negative resistance device. LBTs for the study have been fabricated and analysed. The devices have been shown to function at much lower voltage and current levels than those reported earlier/ and thus have been shown to be suitable for lower power applications. The issues of agreements and discrepancies of the experimental results with the original DC model of the device have been highlighted and discussed. The factors contributing to the drain current of the MOSFET in the LBT have been identified. It has also been shown that in the real case of an LBT in operation, the MOSFET in it does not function as a discrete device for the same conditions of voltages and current levels as in an LBT. As per the present study, it is assessed to be influenced by the presence of the BJT in operation and this effect is felt more at the lower current levels of operation. With a separate and tailored p-well implantation the
possibility of fabrication of LBTs with a CMOS technology is established.
Along with a couple of polysilicon resistors, the LBTs have been successfully made to perform in the common-collector configuration as the bistable storage element of SRAM cell (as proposed in the literature). The bistable element with the LBT in common-emitter mode also has been visualised and practically achieved with the fabricated devices. The WRITE transients for either case have been simulated for various levels of WRITE voltages and their time of hold.The speed of Writing achieved are found comparable with that of the standard SRAMs. The advantages and disadvantages of using the LBT in either mode have been highlighted and discussed. The power consumption of the bistable element with the LBT in either mode is however shown to be the same.
A different approach of READING has been proposed to overcome the factors known to increase the cycle time. On the whole, under the present study, the proposal of using LBTs in the bistable storage element of the SRAM cell has been shown to be feasible. Such SRAM circuits can find possible applications in the fields where smaller circuit area is the major concern.
11
Sarkar, Manju. "Lambda Bipolar Transistor (LBT) in Static Random Access Memory Cell." Thesis, Indian Institute of Science, 1995. http://hdl.handle.net/2005/124.
Full textAbstract:
With a view to reduce the number of components in a Static Random Access Memory (SRAM) cell, the feasibility of use of Lambda Bipolar Transistor (LBT)in the bistable element of the cell has been explored under the present study. The LBT under consideration here comprises of an enhancement mode MOSFET integrated with a parasitic bipolar transistor so as to perform as a negative resistance device. LBTs for the study have been fabricated and analysed. The devices have been shown to function at much lower voltage and current levels than those reported earlier/ and thus have been shown to be suitable for lower power applications. The issues of agreements and discrepancies of the experimental results with the original DC model of the device have been highlighted and discussed. The factors contributing to the drain current of the MOSFET in the LBT have been identified. It has also been shown that in the real case of an LBT in operation, the MOSFET in it does not function as a discrete device for the same conditions of voltages and current levels as in an LBT. As per the present study, it is assessed to be influenced by the presence of the BJT in operation and this effect is felt more at the lower current levels of operation. With a separate and tailored p-well implantation the
possibility of fabrication of LBTs with a CMOS technology is established.
Along with a couple of polysilicon resistors, the LBTs have been successfully made to perform in the common-collector configuration as the bistable storage element of SRAM cell (as proposed in the literature). The bistable element with the LBT in common-emitter mode also has been visualised and practically achieved with the fabricated devices. The WRITE transients for either case have been simulated for various levels of WRITE voltages and their time of hold.The speed of Writing achieved are found comparable with that of the standard SRAMs. The advantages and disadvantages of using the LBT in either mode have been highlighted and discussed. The power consumption of the bistable element with the LBT in either mode is however shown to be the same.
A different approach of READING has been proposed to overcome the factors known to increase the cycle time. On the whole, under the present study, the proposal of using LBTs in the bistable storage element of the SRAM cell has been shown to be feasible. Such SRAM circuits can find possible applications in the fields where smaller circuit area is the major concern.
12
Liou, Chorng-Lii. "An improved formulation of the temperature dependence of the Gummel-Poon bipolar transistor model equations." PDXScholar, 1992. https://pdxscholar.library.pdx.edu/open_access_etds/4361.
Full textAbstract:
A number of shortcomings were found after complete derivation of the temperature dependence of equations, and the expressions related to the Early effect in the present Gummel-Poon 2 model, as implemented in the TEKSPICE program. The formulation and application of improved model equations is presented, followed by a detailed comparison of the existing model with the one developed in this work.
13
Grande, i. Fullana Iria. "Desenvolupament i validació d'un model d'estadificació en el trastorn bipolar: variables clíniques, funcionals i biomarcadors perifèrics." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/126065.
Full textAbstract:
1. Introducció
El trastorn bipolar (TB) és una malaltia crònica, recurrent, i sovint progressiva, que es troba entre les 10 patologies més discapacitants a nivell mundial. Aquesta càrrega de deficiències global no només ve deguda a la pròpies oscil•lacions de l’estat d’ànim sinó també a un reguitzell de condicions comòrbides mèdiques i psiquiàtriques i un deteriorament cognitiu associat. Donada l’extensa evidència d’afectació neuroprogresiva en aquests diferents àmbits, s’ha proposat el caràcter sistèmic del TB i l’aplicabilitat del model d’estadificació en el TB. L’alliberació de diferents factors com factors inflamatoris (citoquines), mediadors d’estrès oxidatiu i factors neurotròfics (factor neurotròfic derivat del cervell (BDNF)) podrien explicar aquest agreujament clínic al llarg de l’evolució del trastorn. Donats aquests antecedents, proposem estudiar variables clíniques i funcionals que puguin establir una classificació segons un model d’estadificació en el TB així com validadors biològics relacionats amb les vies de neuroprogressió esmentades. Considerant el paper clau que juguen les neurotrofines i els seus polimorfismes funcionals, pretenem també estudiar els nivells de BDNF en pacients amb TB en funció de la resposta al tractament.
2. Mètodes
En l’estudi 1 es va realitzar un estudi cas-control aparellat per edat i sexe. S’inclogueren pacients diagnosticats de TB estables (SCID-I). S’exclogueren aquells pacients amb malalties mèdiques comòrbides. Els controls foren familiars sans de primer grau diagnosticats de TB (SCID-I/NP). Es realitzà una entrevista semiestructurada i es determinaren nivells sèrics de citoquines (IL-2, IL-4, IL-6, IL-10, IL-17A), interferó gamma, BDNF i biomarcadors d’oxidació (TBARS, PCC). Una anàlisi de cluster es va dur a terme per construir un model d’estadificació i una regressió logística per a estudiar les associacions entre el model i els biomarcadors.
En l’estudi 2 i 3, es van estudiar pacients diagnosticats de TB lliures de medicació durant un episodi afectiu agut aparellats amb controls sans segons sexe, edat i ètnia. Es va realitzar una avaluació clínica (HDRS, YMRS, CGI, GAF), la determinació de nivells sèrics de BDNF al llarg de 16 setmanes i la del polimorfisme BDNF Val66Met. Les anàlisis es realitzaren a partir d’un model d’efecte mixt.
3. Resultats
En el primer grup de pacients, realitzem una proposta d’estadificació dividint els pacients en dos estadis: el “primerenc” que presenta un menor nombre d’episodis, millor funcionament en la vida diària, major edat a l’inici del TB i major temps d’evolució de la malaltia, comparat amb els pacients compresos en l’estadi “tardà” que mostren resultats oposats en aquestes variables. A més a més, aquesta classificació s’ha vist associada amb un biomarcador lligat a la inflamació, com la IL-6.
En el segon grup de pacients, determinem que els nivells sèrics de BDNF varien al llarg del tractament farmacològic en funció de la presència de resposta al tractament en pacients amb TB que es troben en un episodi afectiu agut. El polimorfisme BDNF Val66Met pot predir variacions dels nivells de BDNF durant el tractament en pacients amb TB que es troben en un episodi afectiu agut. La polaritat de l’episodi sembla influir també en la trajectòria dels nivells sèrics de BDNF al llarg del tractament en pacients amb TB que es troben en un episodi afectiu agut.
4. Conclusions
Les variables clíniques i funcionals poden ser d’ajuda a l’hora de determinar un model d’estadiatge en el TB basat en un estadi primerenc i un altre de tardà. El biomarcador minflamatori IL-6 s’ha determinat com un possible validador biològic d’aquest model. Els nivells neurotròfics de BDNF varien al llarg del tractament farmacològic en funció de la resposta al tractament, el polimorfisme BDNF Met66Val i la polaritat de l’episodi inicial.1. Introduction Bipolar disorder (BD) is among the 10 most disabling conditions world-wide since several medical and psychiatric comorbidities as well as cognitive deficits are associated. Due to the weight of evidence suggesting the neuroprogressive evolution of the disorder, BD has been put forward as a systemic disorder and the applicability of a model of staging is under consideration. Factors such as cytokines (IL-6), oxidative stress and neurotrophic factors (BDNF) have been proposed to explain the evolution of the disorder. In this project, we aimed to study a staging model for BD based on clinical and functional variables as well as biological validators. Moreover, we studied to study the role of neurotrophins and their functional polymorphisms in the response to treatment in BD. 2. Methods In study 1, stable bipolar patients were matched for age and gender with first degree relatives of bipolar patients. Socio-demographic, clinical and functional data were collected. Cytokines, BDNF, biomarkers of oxidative stress were assessed. Cluster analysis was carried out to build a staging model and logistic regression was conducted to study any associations between the model and biomarkers. In studies 2 and 3, bipolar patients who were medication-free at baseline and in an acute mood episode were recruited and matched with healthy controls. Clinical evaluation, serum BDNF and BDNF Val66Met polymorphism were assessed along the 16-week follow-up. 3. Results In the first group of patients, the staging model depicted an early- and a late-stage regarding functioning, number of episodes, age at onset of the disorder and time elapsed since the first episode. IL-6 was associated with this model. In the second group of patients, the BDNF Val66Met polymorphism predicted changes in BDNF levels, and the response to treatment and the polarity of the episode were associated with variations in BDNF levels. 4. Conclusions Functional and clinical variables may determine a model of staging, defined with an early and late stage. IL-6 may be a biological validator. BDNF levels vary along treatment according to response to treatment, the BDNF Val66Met polymorphism and polarity of the episode.
14
Zhao, Danyang. "Examining the impact of exposure to a bipolar disorder storyline using the entertainment overcoming resistance model." Thesis, The Florida State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1559587.
Full textAbstract:
The effects of entertainment-education narratives on pro-social, story-consistent beliefs and behaviors have been discussed by many. Less research has looked into the underlying mechanisms that facilitate these effects. Past research have attempted to explain the process through which persuasion occurs in narrative using a variety of theories, models and constructs. Recently, a better-integrated and structured theoretical framework — the Entertainment Overcoming Resistance Model — has been proposed to account for the persuasive effects. It clarifies the role of some similar constructs in narrative message processing. The present study examined several hypothesized relationships in the EORM by investigating the effects of exposure to a major bipolar disorder storyline embedded in a popular serial teen drama — 90210 — compared to those of exposure to a PSA addressing bipolar I disorder. The role of identification, transportation, parasocial interaction, perceived similarity, counterarguing, reactance, and perceived invulnerability in producing persuasive outcomes were re-examined in this bipolar I disorder E-E narrative. Participants were randomly assigned to one of three viewing conditions, a Stormwater Runoff Public Service Announcement plus a video of 90210 excerpts containing bipolar disorder storyline, a bipolar disorder PSA paired with a video of 90210 excerpts without bipolar disorder storyline, and the Stormwater Runoff PSA plus the video of 90210 excerpts without bipolar disorder storyline (control condition). They completed a questionnaire immediately after viewing each video and filled out another online follow-up questionnaire two weeks later to assess their responses to the program. Results of the study indicated the following: (1) Relative to the control condition, BPI E-E narrative exposure was not associated with greater overall pro-treatment behavioral intention and behaviors regarding BPI but did enhance the behavioral intention to seek help from mental health professional regarding BPI; (2) among the three resistance-related variables examined in this study, only perceived invulnerability was negatively associated with behavioral intention; (3) identification with characters was the only construct that contributed to reduced perceived invulnerability; and (4) the additional consideration of perceived invulnerability of "others" seemed helpful in understanding the effects of the bipolar I disorder narrative. Implications of findings, suggested areas of future research, and limitations of the present study are discussed.
15
Gerstein, Rachel. "THE LONG-TERM COURSE OF BIPOLAR SPECTRUM DISORDER: APPLICATIONS OF THE BEHAVIORAL APPROACH SYSTEM (BAS) MODEL." Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/73971.
Full textAbstract:
PsychologyPh.D.
In this study, I tested predictions of the Behavioral Approach System (BAS) model as applied to the course of bipolar spectrum disorders. In this model, when a vulnerable individual experiences a BAS activation-relevant event, the weak regulatory strength of the BAS interacts with pre-event BAS state and is likely to lead to hypomania/mania. In contrast, when a vulnerable individual experiences a BAS deactivation-relevant event, the weak regulatory strength of the BAS interacts with pre- event BAS state and is likely to lead to depression. A secondary goal of this study involved comparing the BAS model to the cognitive-vulnerability stress model of bipolar disorder. Toward this end, data from a sample of 217 individuals (112 individuals with a diagnosis in the bipolar spectrum and 105 demographically similar, normal controls) participating in the Longitudinal Investigation of Bipolar Spectrum Disorders (LIBS) Project, a two-site prospective examination of the role of BAS, cognitive styles, and life events in the course of bipolar disorders among college students, were analyzed. The results of this study suggest that there is some support for both the BAS model and the cognitive-vulnerability stress model. Specifically, BAS-relevant cognitive styles, in interaction with congruent positive life events, predicted hypomanic episodes. There was less support for either model in the prediction of depression. There was some support for BAS sensitivity and BAS-relevant events each predicting the course of bipolar disorder. However, there was no support for the interaction of BAS sensitivity and BAS-relevant events predicting the type and number of mood episodes. As such, this study found more support for a BAS-related cognitive vulnerability-stress model, as compared to the "pure" BAS model, as applied to bipolar spectrum disorders. Following a review of the results, strengths and limitations, as well as clinical implications and potential future research directions are discussed.
Temple University--Theses
16
VUMMIDI, MURALI KRISHNA PRASAD. "Thermionic Emission Diffusion Model of InP-based Pnp Heterojunction Bipolar Transistor with Non-Uniform Base Doping." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1060110500.
Full text
17
Montgomery, Leigh Ann. "The relationship between the health belief model constructs and medication compliance in the treatment of bipolar disorder." Access restricted to users with UT Austin EID Full text (PDF) from UMI/Dissertation Abstracts International, 2001. http://wwwlib.umi.com/cr/utexas/fullcit?p3034938.
Full text
18
Bhattacharyya, Arkaprava. "Non quasi-static effects investigation for compact bipolar transistor modeling." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14294/document.
Full textAbstract:
Les transistors rapides actuels présentent un retard lorsqu’ils fonctionnent à très hautes fréquences ou en régime transitoire rapide. Cet effet est appelé effet non quasi-statique (NQS). Dans cette thèse, l’effet NQS est analysé de manière concise de façon à être directement implanté dans les modèles de composant pour les bibliothèques de circuit en utilisant le langage standard VerilogA. Les mécanismes physiques à la base de l’effet NQS sont évalués dans le domaine de fonctionnement petit signal et les résultats sont comparés aux travaux déjà publiés. S’agissant du modèle standard bipolaire HICUM, les effets NQS latéraux et verticaux sont examinés séparément à partir du même modèle, en régime de fonctionnement transitoire et fréquentiel grâce à un sous-circuit dédié au calcul de la phase du signal. A partir de ce sous-circuit, la modélisation compacte avec HICUM est comparée aux données issues de mesures et issues de simulation amont. Enfin, un nouveau sous-circuit calculant l’excès de phase est proposé pour prendre mieux en compte les effets non quasi-statiques dans les transistors bipolairesModern high speed (RF) transistors encounter certain delay while operated at high frequency or under fast transient condition. This effect is named as Non Quasi Static (NQS) effect. In the current work, NQS effect is analyzed in a concise manner so that it can be readily implemented in a compact model using the VerilogA description language. The basic physics behind this effect is investigated in small signal domain and the results are compared with the published work. In popular bipolar model HICUM lateral and vertical NQS are examined separately and uses the same model for both transient and AC operation which requires an additional minimum phase type sub circuit. Compact modeling with HICUM model is performed in both measurement and device simulated data. At last, an improved excess phase circuit is proposed to model the NQS effect
19
Carolan, Louise. "What basic emotions are experienced in bipolar disorder and how are they are regulated." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/4108.
Full textAbstract:
Introduction: There remains a lack of theoretical models which can adequately account for the key features of bipolar disorders (Power, 2005). Objectives: Firstly, to test the predictions made by the SPAARS model that mania is predominantly characterised by the coupling of happiness with anger, while depression (unipolar and bipolar) primarily comprises of a coupling between sadness and disgust. Secondly, to investigate and compare the coping strategies employed to regulate positive and negative emotion between bipolar, unipolar and control groups. Design: A cross sectional design was employed to examine the differences within and between the bipolar, unipolar and control groups in the emotions experienced and the strategies used to regulate emotion. Data were analysed using ANOVAs. Method: Psychiatric diagnoses in the clinical groups were confirmed using the SCID. Current mood state was measured using the BDI-II, STAI and the MAS. The Basic Emotion Scale was used to explore the emotional profiles and the Regulation of Emotion Questionnaire was used to measure coping strategies. Results: The results confirmed the predictions made by the SPAARS model about the emotions in mania and depression. Elevated levels of disgust were also found in the bipolar group generally. The clinical groups used internal dysfunctional strategies more often than the controls for negative emotion. The bipolar group used external dysfunctional strategies more frequently than the controls for positive emotion. Conclusion: The results support the predictions made by the SPAARS model and suggest that disgust plays a key role in bipolar disorder. Strengths and limitations are discussed and suggestions for future research are explored.
20
MARTINO, MATTEO. "A working model on large-scale spatio-temporal organization of brain functioning and its implications for bipolar disorder." Doctoral thesis, Università degli studi di Genova, 2018. http://hdl.handle.net/11567/929968.
Full text
21
Beleca, Radu. "Investigation of bipolar charge distribution of pharmaceutical dry powder aerosols using the phase Doppler anemometry system." Thesis, Brunel University, 2012. http://bura.brunel.ac.uk/handle/2438/11271.
Full textAbstract:
Electrostatic properties of formulation component materials and blends play an important role in dry powder inhalation (DPI) products, and that valid measurement of charge distribution will lead to more precise control of powder behavior in DPI manufacturing processes. Ultra-fine powders are known to be bipolarly charged, have non-spherical shapes and tend to be highly cohesive. Real time, non-invasive techniques need to be developed to obtain a precise and accurate time-history characteristic of electrically charged powders as they aerosolize from a DPI product, and how this measure relates to materials behavior throughout the various steps of a manufacturing process i.e. from drug micronisation, blending with lactose, through to filling dose units. A novel non-invasive technique for simultaneous measurement of size and charge of pharmaceutical powders is considered which employs the Phase Doppler Anemometry (PDA) system. Previous research demonstrated the advantages of this technique in measuring the bipolar charge distribution on a population of particles. These findings led to significant improvements in understanding performance of dry powder formulations, manufacturing processes and development of new platforms for inhaled drug delivery. The main aim of this research is to perform an investigation of electrostatic propertiesof pharmaceutical dry aerosols using the PDA system. The PDA technique was used to track the motion of charged particles in the presence of an electric field. The magnitude as well as the polarity of the particle charge can be obtained by solving the equation of particle motion in DC and AC fields combined with the simultaneous measurement of its size and velocity. The results show the capability of the technique to allow real-time size and charge distribution in the control of dry powder attributes that are critical to fully understanding manufacturing design space. The data obtained from initial investigations of electrical properties of pharmaceutical powders and bipolar charge measurements was used to perform an in-depth study of electrostatic properties of pharmaceutical aerosols dispensed by dry powder inhaler (DPI) devices. The delivery of a drug to the lungs can only be achieved by a combination of inhaler device and drug formulation which is capable of producing an aerosol of an aerodynamic diameter smaller than 5 μm and of appropriate charge. The aerosols generated by these devices are often bipolarly charged and can influence specific site deposition in human lung. By controlling the electrostatic charge generated by tribielectrification, it may be possible to achieve the desired drug deposition in the airways. Bipolary charged dispensed ultrafine particles are inhaled through the extrathoracic and tracheobronchial airways down into the alveolar region. Anatomically realistic respiratory airways and computation fluid dynamics (CFD) models have been created to study airflow structures and predict aerosol deposition within the human respiratory system using visible human data sets, human casts and morphometric data. Many theoretical studies of charged aerosol deposition in human respiratory systems have been developed, however getting real time, non-intrusive data of bipolar charge levels on aerosols dispensed from DPI’s within the human respiratory system represents a challenging issue. This research project presents a simplified human upper airway model which combined with the modified Phase Doppler Anemometry (PDA) system is able to provide real time bipolar charge distributions of aerosols delivered from several commercially available DPI devices. A three dimensional (3D) reconstruction of the upper respiratory system was performed from two dimensional (2D) images obtained from computerized tomography (CT), magnetic resonance imaging (MRI) and cryosectioned images available from Visible Human Server data set (Ecole Polytechnique Fédérale de Lausanne). The resulting dimensions of the model were consistent with morphometric data from the literature from which the simplified upper airway model consisting of two connected segments, i.e., the oral airways from the mouth to trachea (Generation G0), was created. The findings of this study provided a better understanding of the interaction between specific active ingredients and DPI devices. These results may be used in designing future generation DPI devices and a better understanding of aerosol transport and deposition efficiency within the human airways.
22
Terbach, Nicole Jennifer. "The epilepsy and bipolar disorder drug valproic acid : Identification of an uptake mechanism using the biomedical model dictyostelium discoideum." Thesis, Royal Holloway, University of London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531312.
Full text
23
Karlbom, Linda. "Så är det inte längre : Närståendes vardag efter patient- och närståendeutbildning vid bipolär sjukdom." Thesis, Ersta Sköndal högskola, Institutionen för vårdvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:esh:diva-2166.
Full text
24
Landers, Courtney Amaryllis. "Using a porcine maternal infanticide model to investigate the inheritance of human puerperal psychosis." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/284358.
Full textAbstract:
Puerperal Psychosis is the most severe form of postnatal psychiatric illness, and is a psychiatric emergency. Human-based research to find a means of genetically predicting a woman's risk of puerperal psychosis has so far failed to reliably or reproducibly identify candidate genes or pathways, due to problems common within the field of psychiatric genetics, leading to the proposal of using an animal model in the form of Porcine Maternal Infanticide. In this project, the author has aimed to understand the pathophysiology of PMI using NGS technologies in order to 1) extend the validity of PMI as a model for PP; 2) determine future steps for development of the PMI model; and 3) generate insights into the management of PMI (and by extension PP) via prediction and detection of a puerperal trigger. These aims have been pursued via two experiments. In the first, the author has created RNA-Seq libraries from archival RNA, and then performed differential gene expression analysis. The results indicated that RNA-Seq technologies can be used with archival RNA samples, but using such samples introduces the risk of degradation-based bias. The substantial influence of outliers, confounding factors and sample size on the results prevented reliable identification of candidate genes" but provide concrete guidelines development of the Porcine Maternal Infanticide model. In the second, the author has created MBD-Seq libraries from archival tissue, and then performed differential methylation analysis. The results indicated that it is possible to use MBD-Seq technologies with Sus scrofa brain tissue. Once again, the effect of confounding factors and sample size on the results prevented reliable identification of candidate genes, but provide guidance for development of the Porcine Maternal Infanticide model.
25
Bailey, Bridget Catherine. "Comparing Psychotherapy With and Without Medication in Treating Adults with Bipolar II Depression: A Post-hoc Analysis." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1593624227017954.
Full text
26
Queiroz, Ana Isabelle de Gois. "Efeitos do dimesilato de lisdexanfetamina em ratos: relevÃncia como modelo animal do episÃdio de mania." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10261.
Full textAbstract:
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorO Transtorno Afetivo Bipolar à um transtorno mental severo que acomete cerca de 1,5% da populaÃÃo mundial e se caracteriza pela oscilaÃÃo de humor entre a depressÃo e a mania, interferindo no desempenho do indivÃduo em termos pessoais e profissionais, bem como sendo responsÃvel por alto nÃmero de suicÃdios. Todos esses fatores o caracterizam como um problema de saÃde pÃblica. Seu mecanismo fisiopatolÃgico ainda nÃo à totalmente conhecido e o arsenal terapÃutico atual ainda à escasso, necessitando de contÃnuas pesquisas nesse Ãmbito. Observando a necessidade de maior disponibilidade de modelos animais de mania para maiores pesquisas à que o estudo objetivou investigar um novo modelo animal de mania. O desenho experimental da pesquisa seguiu os critÃrios para determinar um modelo animal que sÃo: a validade de face (onde busca-se mimetizar no animal comportamento caracterÃstico na doenÃa), validade de constructo (a fisiopatologia da doenÃa) e a validade preditiva ( se os medicamentos jà estabelecidos para determinada doenÃa sÃo capazes de reverter e prevenir os efeitos do fÃrmaco que induz a patologia). Logo, o presente trabalho se propÃs a investigar a atividade do Dimesilado de Lisdexanfetamina (LDX), prÃ-fÃrmaco que ao ser metabolizado a d-anfetamina passa a exercer sua atividade psicoestimulante como possÃvel agente em um modelo animal de mania. O tratamento com D-ANF induz hiperlocomoÃÃo e à considerado como um modelo animal de mania bipolar jà estabelecido. Por isso, procurou-se determinar as alteraÃÃes comportamentais e de estresse oxidativo induzidas pela administraÃÃo via oral sub-crÃnica de LDX, bem como a reversÃo e prevenÃÃo deste efeito ao tratar os ratos com lÃtio, medicamento protÃtipo como estabilizante do humor. Um aumento significativo no comportamento locomotor foi induzido por LDX (10 e 30 mg/Kg). Para determinar os efeitos de LÃtio (Li) nas alteraÃÃes induzidas por LDX nos ratos do grupo reversÃo, o protocolo seguiu a administraÃÃo de LDX (10 ou 30 mg / Kg) ou soluÃÃo salina durante 14 dias. Entre os dias 8o e 14o os animais receberam Li (47,5 mg / kg, ip) ou soluÃÃo salina. No protocolo de prevenÃÃo, os ratos foram prÃ-tratados com soluÃÃo salina ou Li antes da administraÃÃo de LDX. Os nÃveis de Glutationa Reduzida (GSH) e de peroxidaÃÃo lipÃdica foram determinados no cÃrtex prÃ-frontal (PFC), hipocampo (HC) e estriado (ST) de ratos. Constatou-se que o LÃtio preveniu a hiperlocomoÃÃo induzida por LDX, nas doses de 10 e 30 mg/kg, mas somente reverteu a hiperlocomoÃÃo quando utilizada a dose de 10 mg/ kg de LDX. AlÃm disso, ambas as doses de LDX diminuÃram o conteÃdo de GSH (em ST e PFC), enquanto que Li foi capaz de reverter e prevenir estas alteraÃÃes, principalmente no PFC. LDX (10 e 30 mg / kg) aumentou a peroxidaÃÃo lipÃdica, que foi revertida e prevenida por Li. Diante dos resultados em termos de hiperlocomoÃÃo e estresse oxidativo demonstrou-se que o LDX conseguiu induzir tais parÃmetros, se mostrando como uma promessa de modelo animal alternativo de mania.
27
Amimi, Adel. "Modèle électro-thermique unidimensionnel du transistor bipolaire à grille isolée (IGBT) pour la simulation de circuits de puissance." Rouen, 1997. http://www.theses.fr/1997ROUES033.
Full textAbstract:
Dans le domaine de l'électronique de puissance, où l'environnement et le mode de fonctionnement du composant jouent un rôle primordial, nous constatons que les aspects thermiques doivent être évalués de la même manière que les aspects strictement électriques. Cela suppose entre autres que la température interne des composants doit pouvoir évoluer comme toutes les grandeurs électriques. Dans ce contexte, nous avons développé un modèle analytique du transistor bipolaire à grille isolée (IGBT) prenant en compte les interactions électro-thermiques dans le composant, en associant au modèle électrique du composant un réseau thermique. Pour cela, deux solutions de complexité différentes ont été envisagées pour l'élaboration du modèle thermique. La première approche (cellulaire) est basée sur l'analogie électrique-thermique. En effet, la propagation du flux de chaleur dans le composant est modélisée par un réseau cellulaire RTH(I) - CTH(I) dont les caractéristiques sont déterminées à partir de l'impédance thermique transitoire ZTH du composant. La seconde approche (dite mixte), fondée sur la résolution à une dimension de l'équation de diffusion de la chaleur, utilise un calcul plus précis de la température dans la couche de silicium, tout en conservant une représentation à base de cellules RTH-CTH pour l'ensemble du boîtier et de l'environnement. Le modèle électro-thermique ainsi développé est implanté en langage MAST dans le simulateur de circuits Saber.
28
Rosenbaum, Tommy. "Performance prediction of a future silicon-germanium heterojunction bipolar transistor technology using a heterogeneous set of simulation tools and approaches." Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0550/document.
Full textAbstract:
Les procédés bipolaires semi-conducteurs complémentaires à oxyde de métal (BiCMOS) peuvent être considérés comme étant la solution la plus généralepour les produits RF car ils combinent la fabrication sophistiquée du CMOSavec la vitesse et les capacités de conduction des transistors bipolaires silicium germanium(SiGe) à hétérojonction (HBT). Les HBTs, réciproquement, sontles principaux concurrents pour combler partiellement l'écart de térahertzqui décrit la plage dans laquelle les fréquences générées par les transistors etles lasers ne se chevauchent pas (environ 0.3 THz à 30 THz). A_n d'évaluerles capacités de ces dispositifs futurs, une méthodologie de prévision fiable estsouhaitable. L'utilisation d'un ensemble hétérogène d'outils et de méthodes desimulations permet d'atteindre successivement cet objectif et est avantageusepour la résolution des problèmes. Plusieurs domaines scientifiques sont combinés, tel que la technologie de conception assistée par ordinateur (TCAO),la modélisation compacte et l'extraction des paramètres.Afin de créer une base pour l'environnement de simulation et d'améliorerla confirmabilité pour les lecteurs, les modèles de matériaux utilisés pour lesapproches hydrodynamiques et de diffusion par conduction sont introduits dèsle début de la thèse. Les modèles physiques sont principalement fondés surdes données de la littérature basées sur simulations Monte Carlo (MC) ou dessimulations déterministes de l'équation de transport de Boltzmann (BTE).Néanmoins, le module de TCAO doit être aussi étalonné sur les données demesure pour une prévision fiable des performances des HBTs. L'approchecorrespondante d'étalonnage est basée sur les mesures d'une technologie depointe de HBT SiGe pour laquelle un ensemble de paramètres spécifiques àla technologie du modèle compact HICUM/L2 est extrait pour les versionsdu transistor à haute vitesse, moyenne et haute tension. En s'aidant de cesrésultats, les caractéristiques du transistor unidimensionnel qui sont généréesservent de référence pour le profil de dopage et l'étalonnage du modèle. Enélaborant des comparaisons entre les données de références basées sur les mesureset les simulations, la thèse fait progresser l'état actuel des prévisionsbasées sur la technologie CAO et démontre la faisabilité de l'approche.Enfin, une technologie future de 28nm performante est prédite en appliquantla méthodologie hétérogène. Sur la base des résultats de TCAO, leslimites de la technologie sont soulignéesBipolar complementary metal-oxide-semiconductor (BiCMOS) processescan be considered as the most general solution for RF products, as theycombine the mature manufacturing tools of CMOS with the speed and drivecapabilities of silicon-germanium (SiGe) heterojunction bipolar transistors(HBTs). HBTs in turn are major contenders for partially filling the terahertzgap, which describes the range in which the frequencies generated bytransistors and lasers do not overlap (approximately 0.3THz to 30 THz). Toevaluate the capabilities of such future devices, a reliable prediction methodologyis desirable. Using a heterogeneous set of simulation tools and approachesallows to achieve this goal successively and is beneficial for troubleshooting.Various scientific fields are combined, such as technology computer-aided design(TCAD), compact modeling and parameter extraction.To create a foundation for the simulation environment and to ensure reproducibility,the used material models of the hydrodynamic and drift-diffusionapproaches are introduced in the beginning of this thesis. The physical modelsare mainly based on literature data of Monte Carlo (MC) or deterministicsimulations of the Boltzmann transport equation (BTE). However, the TCADdeck must be calibrated on measurement data too for a reliable performanceprediction of HBTs. The corresponding calibration approach is based onmeasurements of an advanced SiGe HBT technology for which a technology specific parameter set of the HICUM/L2 compact model is extracted for thehigh-speed, medium-voltage and high-voltage transistor versions. With thehelp of the results, one-dimensional transistor characteristics are generatedthat serve as reference for the doping profile and model calibration. By performingelaborate comparisons between measurement-based reference dataand simulations, the thesis advances the state-of-the-art of TCAD-based predictionsand proofs the feasibility of the approach.Finally, the performance of a future technology in 28nm is predicted byapplying the heterogeneous methodology. On the basis of the TCAD results,bottlenecks of the technology are identified
Bipolare komplementäre Metall-Oxid-Halbleiter (BiCMOS) Prozesse bietenhervorragende Rahmenbedingungen um Hochfrequenzanwendungen zurealisieren, da sie die fortschrittliche Fertigungstechnik von CMOS mit derGeschwindigkeit und Treiberleistung von Silizium-Germanium (SiGe) Heterostruktur-Bipolartransistoren (HBTs) verknüpfen. Zudem sind HBTs bedeutendeWettbewerber für die teilweise Überbrückung der Terahertz-Lücke, derFrequenzbereich zwischen Transistoren (< 0.3 THz) und Lasern (> 30 THz).Um die Leistungsfähigkeit solcher zukünftigen Bauelemente zu bewerten, isteine zuverlässige Methodologie zur Vorhersage notwendig. Die Verwendungeiner heterogenen Zusammenstellung von Simulationstools und Lösungsansätzenerlaubt es dieses Ziel schrittweise zu erreichen und erleichtert die Fehler-_ndung. Verschiedene wissenschaftliche Bereiche werden kombiniert, wie zumBeispiel der rechnergestützte Entwurf für Technologie (TCAD), die Kompaktmodellierungund Parameterextraktion.Die verwendeten Modelle des hydrodynamischen Simulationsansatzes werdenzu Beginn der Arbeit vorgestellt, um die Simulationseinstellung zu erläuternund somit die Nachvollziehbarkeit für den Leser zu verbessern. Die physikalischenModelle basieren hauptsächlich auf Literaturdaten von Monte Carlo(MC) oder deterministischen Simulationen der Boltzmann-Transportgleichung(BTE). Für eine zuverlässige Vorhersage der Eigenschaften von HBTs muss dieTCAD Kon_guration jedoch zusätzlich auf der Grundlage von Messdaten kalibriertwerden. Der zugehörige Ansatz zur Kalibrierung beruht auf Messungeneiner fortschrittlichen SiGe HBT Technologie, für welche ein technologiespezifischer HICUM/L2 Parametersatz für die high-speed, medium-voltage undhigh-voltage Transistoren extrahiert wird. Mit diesen Ergebnissen werden eindimensionaleTransistorcharakteristiken generiert, die als Referenzdaten fürdie Kalibrierung von Dotierungspro_len und physikalischer Modelle genutztwerden. Der ausführliche Vergleich dieser Referenz- und Messdaten mit Simulationengeht über den Stand der Technik TCAD-basierender Vorhersagenhinaus und weist die Machbarkeit des heterogenen Ansatzes nach.Schlieÿlich wird die Leistungsfähigkeit einer zukünftigen Technologie in28nm unter Anwendung der heterogenen Methodik vorhergesagt. Anhand derTCAD Ergebnisse wird auf Engpässe der Technologie hingewiesen
29
Zhang, Yongjian. "Investigation of electrical and optical characterisation of HBTs for optical detection." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/investigation-of-electrical-and-optical-characterisation-of-hbts-for-optical-detection(3c47e08f-9201-4465-b2b5-268aa0360309).html.
Full textAbstract:
In this thesis, a detailed study of the electrical and optical characterisations of Heterojuction Bipolar Transistors (HBTs) for optical detection is presented. By comparing both DC and optical characterisations between In0.49Ga0.51P/GaAs Single Heterojuction Bipolar Transistors (SHBTs) and Double Heterojuction Bipolar Transistors (DHBTs), the advantages of using the DHBT as a short wavelength detector are shown. Phenomena related to the base region energy band bending in the DHBT caused by a self-induced effective electric field is discussed and its effects on the performance of the device are elaborated. The use of an eye diagram has been employed to provide requisite information for performance qualification of SHBT/DHBT devices. These give a more detailed understanding compared to conventional S-parameters method. A detailed comparison of In0.49Ga0.51P/GaAs SHBT and DHBT performance using an eye diagram as a functional tool by adopting a modified T-shaped small signal equivalent circuit are given. By adopting this modified T-shaped small signal equivalent circuit, the use of In0.49Ga0.51P/GaAs Double Heterojuction Phototransistors (DHPT) as a short wavelength photodetector is analysed. It is therefore shown that an eye diagram can act as a powerful tool in HBTs/HPTs design optimisations, for the first time in this work. In order to predict the spectral response (SR) and optical characterisations of GaAs-based HPTs, a detailed theoretical absorption model is also presented. The layer dependence of an optical flux absorption profile, along with doping dependent absorption coefficients are taken into account for the optical characterisation prediction. With the aim of eliminating the limitation of current gain as a prerequisite, analytical modelling of SR has been developed by resolving the continuity equation and applying realistic boundary conditions. Then, related physical parameters and a layer structure profile are used to implement simulations. A good agreement with the measured results of the Al0.3Ga0.7As/GaAs HPT is shown validating the proposed theoretical model.
30
Roker, Rosalyn. "Perspectives of older Blacks and Whites living with serious mental illness about outpatient mental health services." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7708.
Full textAbstract:
In the United States, over three million adults, age 50 and older, reported a diagnosis of serious mental illness (SMI) in the past year. Most of them live in community-settings and are less likely than younger adults to utilize mental health treatment. Lack of and insufficient treatment for SMI places them at increased risk of morbidity, earlier mortality, cognitive decline, and diminished quality of life. The current study aimed to: (1) examine the factors that influence Black and White older adults, who live with SMI, to seek and engage in outpatient mental health treatment; (2) identify the perspectives of Black and White older adults, who live with SMI, on the issues of accessibility, affordability, appropriateness, and availability of outpatient mental health services; and (3) determine whether the perspectives of Blacks and Whites are different on the issues of accessibility, affordability, appropriateness, and availability of outpatient mental health services.
I developed a qualitative, interview-based study using the health belief model (HBM) as the theoretical framework. Individual semi-structured interviews were conducted with 19 participants, between the ages of 50-70 years (mean age 58.9), who had a clinical diagnosis of bipolar disorder, schizoaffective disorder, and schizophrenia. The interviews were audiotaped, transcribed verbatim, coded and analyzed using thematic analysis.
Data themes related to factors that influenced outpatient mental health treatment and services were identified and organized based on the six HBM constructs. Perceived barriers to mental health treatment engagement included lack of knowledge about available treatment and services in the community, poor mental health literacy, and stigma. Improved sense of well-being and increased socialization were perceived benefits of mental health treatment engagement. Risk of homelessness emerged from the data as the main influence for Black and White older adults, who live with SMI, to seek and engage in outpatient mental health treatment. For all participants, access to and availability of mental health services were not current issues. All except one participant had some type of medical coverage for their treatment and most of them felt that their current treatment was appropriate. There were no differences between Black and White older adults on the issues of accessibility, affordability, appropriateness, and availability of outpatient mental health services. In addition, Black participants did not feel a need for mental health services to be specifically tailored to Black older adults, and instead indicated they saw no differences in Blacks and Whites related to mental health services. These findings are contrary to existing research and may be indicative of the gravity of mental illness-related stigma, compared to racial stigma.
Better promotion of available mental health services in the community, mental health outreach, and community education about mental illness may be helpful for earlier identification of symptoms related to mental illness, earlier treatment and intervention, stigma reduction, and improved health and quality of life for community-residing older adults who live with SMI.
31
Boissy, Clément. "Transport de matière au sein du film passif : Développement d’une méthodologie sélective corrélant les Point Defect Model et les modèles descriptifs." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0136.
Full textAbstract:
Le développement de la plaque bipolaire - PB -métallique nécessite une amélioration des propriétés du matériau qui la constitue. L'utilisation de l'acier implique une meilleure compréhension du film passif - FP. En effet, le cahier des charges de la PB demande une bonne conduction électronique ainsi qu'une longue durée de vie. L'amélioration de ces paramètres passe par une meilleure corrélation et compréhension entre les propriétés semi-conductrices et la résistance à la corrosion. La difficulté liée à l'étude de la passivation réside dans les nombreux phénomènes modifiant le comportement du film passif. De nombreux modèles présentés dans la littérature peuvent être utilisés pour caractériser la passivation. L'un des principaux, le Modèle de Défauts Ponctuels de D. D. Macdonald (Point Defect Model - PDM), décrit le FP à partir d'une série de réactions électrochimiques se déroulant à l'interface métal/oxyde et à l'interface oxyde/électrolyte. La réactivité est limitée par le transport de matière à travers l'oxyde. Après une étude bibliographique, ce phénomène semble être un paramètre discriminant dans le choix des modèles. Une méthode de sélection permettant une utilisation de chacun de ces modèles en fonction de leurs spécificités est proposée. Ainsi, cette méthode est basée sur la corrélation entre la mesure du transport de matière à partir des équations du PDM et l'analyse des Spectres d'Impédance Electrochimique (SIE). Le PDM caractérisant le transport de matière indépendamment de la SIE, il devient possible de déterminer le bien-fondé de la prise en compte de celui-ci dans les mesures de spectroscopie d'impédance électrochimique. L'évolution de la densité du porteur de charge majoritaire avec le potentiel de formation de l'oxyde permet d'accéder au coefficient de transport à partir des équations du PDM. Connaissant l'épaisseur de l'oxyde par des mesures XPS, la constante de temps et la fréquence caractéristique peuvent être déterminées. Sur la base de ces deux valeurs, un modèle descriptif d'analyse des spectres est sélectionné en évitant le sur-paramétrage. Cette méthode est appliquée d’abord à un matériau modèle, le chrome pur exposé à un milieu acide (pH 2), à différentes températures (30°C et 80°C). Elle valide la nécessité de la prise en compte du transport de matière à 80°C ainsi que la présence d'une surface composée d'une couche d'oxyde interne et d'une couche d'hydroxyde externe. Dans un second temps, cette méthode est utilisée sur un matériau industriel, un acier de type AISI 316L, à différents pH (1,2 et 3) et à différentes températures (30°C et 80°C). Elle a permis de décrire l'oxyde en surface comme une jonction p-n prenant en compte une couche riche en chrome interne avec un gradient de concentration de fer. Cette méthode a permis de caractériser de manière approfondie l'acier de type AISI 316L. Bien que ne concernant que le substrat, cette étape est déterminante dans l'amélioration des performances des PB métalliquesDevelopments in metallic bipolar plate, to apply more widely fuel cells, require an improved of the constitutive material. The use of stainless steel calls for a good understanding of the passive film. The required specifications are for good electrical conductivity and a long life-time. Those two parameters correspond to a correlation between the semiconductive properties and the good corrosion behavior. Nevertheless, the main problems of the passivity lie on the multiplicity of the phenomena that alter the passive film behavior. Numerous models described in the literature can be used to characterize the passivation. The Point Defect Model (PDM) describes the passivation through electrochemical reactions at the metal / oxide and at the oxide / electrolyte interfaces. The reactivity is limited by mass transport through the oxide. From the literature, those phenomena seems to be a discriminating parameter in the choice of a model. The selective method proposed allows us to use each model taking into account their specifics. This methodology is based on the correlation between the mass transport characterization, thanks to the PDM, and the analysis of the Electrochemical Impedance Spectroscopy (EIS). The PDM determines the transport coefficient apart from EIS measurements, so to validate the consideration of the mass transport during the analysis of the electrochemical impedance spectra. The evolution of the main charge carrier density as a function of the oxide formation potential allows us to calculate the transport coefficient from PDM equations. Thanks to the thickness of the oxide (determined by X-ray Photoelectron Spectroscopy), the time constant of the mass transport is determined. Based on this value, a descriptive model is used to analyze the EIS data, avoiding overparametrization. This method is applied first on a model material, pure chromium exposed to acidic solution (pH 2) at several temperatures (30°C and 80°C). It shows that the mass transport has to be taken into account at 80°C and the EIS model considers an inner chromium oxide layer and an outer chromium hydroxide. Secondly, the method is used to characterize an industrial material, AISI 316L stainless steel, at several pH (1, 2 and 3) and at several temperatures (30°C and 80°C). In this case, the oxide is describe as a p-n semiconductor junction with an chromium rich inner layer and an outer iron rich layer. The present methodology permits to deeply characterize the AISI 316L stainless steel. Even if this study concerns the substrate, this step is decisive to improve the performances of the metallic bipolar plates
32
Woodcock, Cassandra. "The Design and Validation of a Computational Rigid Body Model for Study of the Radial Head." VCU Scholars Compass, 2013. http://scholarscompass.vcu.edu/etd/3277.
Full textAbstract:
Rigid body modeling has historically been used to study various features of the elbow joint including both physical and computational models. Computational modeling provides an inexpensive, easily customizable, and effective method by which to predict and investigate the response of a physiological system to in vivo stresses and applied perturbations. Utilizing computer topography scans of a cadaveric elbow, a virtual representation of the joint was created using the commercially available MIMICS(TM) and SolidWorks(TM) software packages. Accurate 3D articular surfaces, ligamentous constraints, and joint contact parameters dictated motion. The model was validated against two cadaveric studies performed by Chanlalit et al. (2011, 2012) considering monopolar and bipolar circular radial head replacements in their effects on radiocapitellar stability and respective reliance upon lateral soft tissues, as well as a comparison of these with a novel anatomic radial head replacement system in an elbow afflicted with the “terrible triad” injury. Rigid body simulations indicated that the computational model was able to accurately recreate the translation of forces in the joint and demonstrate results similar to those presented in the cadaveric data in both the intact elbow and in unstable injury states. Trends in the resulting data were reflective of the average behavior of the cadaveric specimens while percent changes between states correlated closely with the experimental data. Information on the transposition of forces within the joint and ligament tensions gleaned from the computational model provided further insight into the stability of the elbow with a compromised radial head.
33
Harmel, Joachim. "Betrachtungen zur Wärmebilanz von Nickel-Metall-Hydrid Batterien." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2005. http://nbn-resolving.de/urn:nbn:de:swb:14-1133961827450-85506.
Full textAbstract:
Heat generation plays an important role for energy storage systems like batteries in electric and hybrid vehicles. In order to investigate the thermal and electrical behaviour the nickel metal hydride batteries were exposed to cycling programs including various methods of battery cooling by flowing air. The second part of the paper describes the simulation of the temperature distribution by using finite element methods (FEM). The electric-thermal battery model was compared with results obtained from temperature measurements at four selected points during battery cycling. The results serve environmentalcareful battery employment for the general, system-oriented viewpoint of the battery condition and form the basis for energy and enviroment save usedDie Wärmeerzeugung spielt bei dem Einsatz von Batterien in Elektro- und Hybridfahrzeugen eine wichtige Rolle. In der Arbeit wird das thermische und elektrische Verhalten der Batterien bei der Belastung mit schnell aufeinander folgenden Höchststromladeimpulsen und -entladeimpulsen untersucht. Die Kühlung der Batterie erfolgte mit verschiedenen Methoden der Luftkühlung. Im zweiten Teil der Arbeit wird die Simulation der Temperaturverteilung mittels Finiter Element Methoden (FEM) beschrieben. Die mit einem elektrisch-thermischen Batteriemodell simulierten Temperaturen werden mit den an verschiedenen Punkten experimentell gemessenen Zelltemperaturen verglichen. Die Ergebnisse dienen zur ganzheitlichen, systemorientierten Betrachtungsweise des Batteriezustandes und bilden die Grundlage für einen energie- und umweltschonenden Batterieeinsatz
34
Ang, Oon Sim. "Modeling of double heterojunction bipolar transistors." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29458.
Full textAbstract:
A one-dimensional analytical model in the Ebers-Moll formulation of a graded base double
heterojunction bipolar transistor (DHBT) is developed and used to examine the effects of base grading, the emitter-base barrier and the base-collector barrier on the d.c. current gain, offset voltage and the high frequency performance of a N — Al[formula omitted]Ga₁[formula omitted]As/p — Al[formula omitted]Ga₁[formula omitted]As/N — Al[formula omitted]Ga₁[formula omitted]As DHBTs. Recombination processes considered in the space charge regions and the neutral regions are: Shockley-Read-Hall, radiative and Auger. The trade-off between base-grading, which reduces the base current, and the neutral base recombination, which is brought about by varying the aluminium the junctions, results in an optimum aluminium mole fraction profile regarding the d.c. current gain. For high frequency performance, a similar trade-off to that of the d.c. situation
exists. In this case, the important manifestation of the increased collector-base barrier height is an increase in the base transit time. The aluminium mole fraction profile which optimises the unity gain cut-off frequency, f[formula omitted], and the unity power gain cut-off frequency, f[formula omitted], is established. DHBTs which are symmetrical, both in aluminium mole fraction and doping concentration profiles, are shown to have low common-emitter offset voltages, V[formula omitted],[formula omitted]. Base-grading reduces V[formula omitted],[formula omitted] in devices in which the difference between the emitter and collector aluminium mole fraction is < 0.1; otherwise, V[formula omitted],[formula omitted] increases as base-grading increases. The model is also used to examine the performance of a N-Al[formula omitted]Ga₁[formula omitted]As/p-In[formula omitted]Ga₁[formula omitted]As/N-Al[formula omitted]Ga₁[formula omitted]As DHBT. It is shown that radiative and Auger recombination limit the d.c. current gain in this device.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
35
Delaney, Larry Duane. "A computer program for the extraction of bipolar transistor spice models /." Online version of thesis, 1992. http://hdl.handle.net/1850/11451.
Full text
36
Weststrate, Marnus. "LC-ladder and capacitive shunt-shunt feedback LNA modelling for wideband HBT receivers." Thesis, University of Pretoria, 2011. http://hdl.handle.net/2263/26615.
Full textAbstract:
Although the majority of wireless receiver subsystems have moved to digital signal processing over the last decade, the low noise amplifier (LNA) remains a crucial analogue subsystem in any design being the dominant subsystem in determining the noise figure (NF) and dynamic range of the receiver as a whole. In this research a novel LNA configuration, namely the LC-ladder and capacitive shunt-shunt feedback topology, was proposed for use in the implementation of very wideband LNAs. This was done after a thorough theoretical investigation of LNA configurations available in the body of knowledge from which it became apparent that for the most part narrowband LNA configurations are applied to wideband applications with suboptimal results, and also that the wideband configurations that exist have certain shortcomings. A mathematical model was derived to describe the new configuration and consists of equations for the input impedance, input return loss, gain and NF, as well as an approximation of the worst case IIP3. Compact design equations were also derived from this model and a design strategy was given which allows for electronic design automation of a LNA using this configuration. A process for simultaneously optimizing the circuit for minimum NF and maximum gain was deduced from this model and different means of improving the linearity of the LNA were given. This proposed design process was used successfully throughout this research. The accuracy of the mathematical model has been verified using simulations. Two versions of the LNA were also fabricated and the measured results compared well with these simulations. The good correlation found between the calculated, simulated and measured results prove the accuracy of the model, and some comments on how the accuracy of the model could be improved even further are provided as well. The simulated results of a LNA designed for the 1 GHz to 18 GHz band in the IBM 8HP process show a gain of 21.4 dB and a minimum NF of only 1.7 dB, increasing to 3.3 dB at the upper corner frequency while maintaining an input return loss below -10 dB. After steps were taken to improve the linearity, the IIP3 of the LNA is -14.5 dBm with only a small degradation in NF now 2.15 dB at the minimum. The power consumption of the respective LNAs are 12.75 mW and 23.25 mW and each LNA occupies a chip area of only 0.43 mm2. Measured results of the LNA fabricated in the IBM 7WL process had a gain of 10 dB compared to an expected simulated gain of 20 dB, however significant path loss was introduced by the IC package and PCB parasitics. The S11 tracked the simulated response very well and remained below -10 dB over the feasible frequency range. Reliable noise figure measurements could not be obtained. The measured P1dB compression point is -22 dBm. A 60 GHz LNA was also designed using this topology in a SiGe process with ƒT of 200 GHz. A simulated NF of 5.2 dB was achieved for a gain of 14.2 dB and an input return loss below -15 dB using three amplifier stages. The IIP3 of the LNA is -8.4 dBm and the power consumption 25.5 mW. Although these are acceptable results in the mm-wave range it was however found that the wideband nature of this configuration is redundant in the unlicensed 60 GHz band and results are often inconsistent with the design theory due to second order effects. The wideband results however prove that the LC-ladder and capacitive shunt-shunt feedback topology is a viable means for especially implementing LNAs that require a very wide operating frequency range and also very low NF over that range.Thesis (PhD(Eng))--University of Pretoria, 2011.
Electrical, Electronic and Computer Engineering
unrestricted
37
Goi, Pedro Domingues. "Evidências clinicas para o modelo de neuroprogressão no transtorno bipolar." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/106844.
Full textAbstract:
O Transtorno Bipolar (TB) é uma patologia prevalente, grave, crônica, e que apresenta um curso longitudinal muito pior que se imaginava décadas atrás. Além da alternância entre períodos de depressão, mania e eutimia, a recorrência e a progressão do TB conferem gravidade e frequência crescentes aos episódios. A neuroprogressão foi um termo cunhado para definir a aceleração do processo de doença e seus fatores subjacentes, como alterações de biomarcadores periféricos, funções cognitivas, neuroimagem e funcionalidade, que emergem em graus variáveis dependendo da fase de evolução. Todas estas evidências justificaram a classificação do TB em estágios clínicos teóricos distintos, que ainda carecem de validação empírica. Um dos mais recentes deles propõe 1 estágio latente e 4 estágios clínicos distintos (Kapczinski et al, 2009) (1). O presente trabalho avaliou, portanto, as diferentes estratégias farmacológicas para a manutenção da eutimia em uma amostra de pacientes com TB em diferentes estágios (artigo 1), e a associação do atraso no tratamento do primeiro episódio com fatores de pior prognóstico e com os estágios do TB (artigo 2). Em conjunto, os resultados mostraram que a abordagem farmacológica instituída pelo psiquiatra clínico, necessária para manter o paciente em eutimia, é diferente conforme a classificação em estágios. O número de fármacos prescrito também está relacionado ao declínio da funcionalidade. Além disso, o atraso no início do tratamento do TB é diretamente proporcional ao estágio de evolução da doença, e está relacionado a fatores de pior prognóstico, como o número de episódios. Os achados fornecem evidência para modificar certas intervenções no TB: a primeira, que diretrizes de tratamento poderiam considerar os estágios, visando um tratamento mais personalizado para guiar a eficácia do tratamento; e por último, que o esforço em diagnosticar e tratar o TB com precisão e rapidez pode ser uma das medidas para frear a neuroprogressão.Bipolar Disorder (TB) is a severe, prevalent, and chronic disease, that exhibits worse longitudinal course than previously thought. Beyond the switching phases of depression, mania and euthymia, recurrence and progression of TB increases severity and frequency of episodes. The neuroprogression was a term created to define the acceleration of the disease and its underlying factors, such as changes in peripheral biomarkers, in cognitive performance, in neuroimaging and functioning, that emerge in different degrees depending on the stage of evolution. All those evidences justify the classification of TB in different clinical stages, which still lack empirical validation. One of most recently proposed staging model describes 1 latent stage and 4 clinical stages (Kapczinski et al, 2009) (1). The present study therefore evaluated the different pharmacological strategies for the maintenance of euthymia in a sample of TB patients at different stages (Article 1), and the association of first-episode tretament delay with poor prognosis and BD stages (Article 2). Together, the results showed that maintenance pharmacological treatment in a naturallistic setting is different according to the staging classification. The number of drugs prescribed is also associated to functioning. Moreover, the treatment delay is positively correlated to the stage of the disease, and is related to poor outcomes (i.e. number of episodes). The findings provide evidence to modify certain interventions in TB: first, that treatment guidelines might consider staging to provide tailored approaches and to guide treatment efficacy; and secondly, that the effort to accurately diagnose and treat TB can be one of the measures to restrain neuroprogression.
38
Souza, Greicy Coelho de. "Estudo dos efeitos do carvedilol em um modelo animal de mania em ratos." reponame:Repositório Institucional da UFC, 2013. http://www.repositorio.ufc.br/handle/riufc/7915.
Full textAbstract:
SOUZA, Greicy Coelho de. Estudo dos efeitos do carvedilol em um modelo animal de mania em ratos. 79 f. Dissertação (Mestrado em Farmacologia) - Universidade Federal do Ceará. Faculdade de Medicina, Fortaleza, 2013.Submitted by denise santos (denise.santos@ufc.br) on 2014-04-09T12:26:56Z No. of bitstreams: 1 2013_dis_gcsouza.pdf: 838295 bytes, checksum: 196f112b0c07b10b688e99fb93c04931 (MD5)
Approved for entry into archive by denise santos(denise.santos@ufc.br) on 2014-04-09T12:27:48Z (GMT) No. of bitstreams: 1 2013_dis_gcsouza.pdf: 838295 bytes, checksum: 196f112b0c07b10b688e99fb93c04931 (MD5)
Made available in DSpace on 2014-04-09T12:27:48Z (GMT). No. of bitstreams: 1 2013_dis_gcsouza.pdf: 838295 bytes, checksum: 196f112b0c07b10b688e99fb93c04931 (MD5) Previous issue date: 2013
Bipolar disorder (BD) is a psychiatric disorder with multifactorial development and neuroprogressive characterized by oscillation between periods of manic and depressive episodes. It is estimated that the disease affects about 1 - 2% of the worldwide population and it takes about 10 years to a definitive diagnosis and appropriate treatment. BD brings many impairment of quality of life of patients, generating high rates of functional disability, comorbidities such as hypertension during the clinical course of the disease and presenting a high prevalence of suicide. The pathophysiology of the disease remains unclear, but many efforts are employed in research to try to elucidate the possible mechanisms involved in BD. The pathways hypothesized to take part of BD pathophysiology includes: dopamine deregulation, increased oxidative stress, decreased levels of neurotrophins such as BDNF, mitochondrial dysfunction among others. Based on the described above we sought to investigate the effects of carvedilol, (CVD), a nonseletive beta-blocker widely used in the treatment of hypertension with antioxidant properties, in a model of mania induced by dimesilate of lisdexamfetamine (LDX) a prodrug metabolized to D-amphetamine, in rats. The experimental design of the study consisted evaluation of CVD against behavioral changes and oxidative stress alterations in two protocols of treatment, prevention and reversal using valproate (VAL) a humor stabilizer as standard drug to assess the effectiveness of CVD. In the prevention protocol the animals were pre-treated for 7 days with CVD, saline or VAL). In the reversal protocol the animals were pre-treated for 7 days with LDX and for further 7 days received CVD, saline or VAL plus LDX. The behavioral determinations of locomotor activity and social interaction were conducted 2 h after the last administration of LDX. Reduced glutathione (GSH) and lipid peroxidation (TBARS) levels were determined in brain areas of the prefrontal cortex (PFC) and striatum (EC) and brain-derived neurotrophic factor (BDNF) in the hippocampus (HC) rats. The results indicated that CVD prevented and reversed the hyperlocomotion and deficit in social contacts induced by LDX. In the neurochemical determinations CVD significantly prevented and reversed the alterations in BDNF, GSH and MDA levels induced by LDX presenting results comparable to those of saline and VAL groups. Therefore, the results of the present study indicates that CVD prevents reverts the behavioral and neurochemical alterations induced by LDX used as an animal model of mania being, thus, a potential drug for the treatment of BD.
O transtorno afetivo bipolar (TAB) é um transtorno psiquiátrico multifatorial, progressivo, que se caracteriza por uma oscilação entre episódios maníacos ou hipomaníacos e depressivos. Estima-se que o transtorno afete cerca de 1 – 2 % da população mundial. O diagnóstico definitivo e o tratamento adequado podem demorar 10 anos para se concretizar. Leva a grande prejuízo à qualidade de vida dos pacientes, gerando altas taxas de incapacidade funcional, comorbidades clínicas, como hipertensão e alta prevalência de suicídio. A fisiopatologia do transtorno ainda permanece obscura, porém muitos esforços são empregados em pesquisas para tentar elucidar os possíveis mecanismos envolvidos no TAB, bem como para melhorar seu tratamento. As hipóteses para explicar a fisiopatologia do TAB incluem: desregulação da dopamina, alterações mitocondriais, aumento do estresse oxidativo, redução dos níveis de neurotrofinas, dentre outras. Diante deste cenário, buscou-se investigar os possíveis efeitos antimaníacos do carvedilol (CVD), um beta-bloqueador não seletivo usado amplamente no tratamento da hipertensão arterial com comprovada ação antioxidante e neuroprotetora. Para tanto, se utilizou um modelo animal de mania induzido por dimesilado de lisdexanfetamina (LDX), recentemente validado por nosso grupo de pesquisa. O LDX é um pró-fármaco que se converte a D-anfetamina, a qual possui efeito psicoestimulante. O CVD foi avaliado em dois protocolos de tratamento, prevenção (simulando a fase de manutenção do TAB) e reversão (simulando a fase de crise do TAB), em ambos o valproato (VAL) foi utilizado como estabilizante do humor padrão. Foram avaliadas no presente estudo alterações comportamentais e de estresse oxidativo. Os animais submetidos aos protocolos de prevenção (animais pré-tratados durante 7 dias com CVD, VAL e Salina e por mais 7 dias com LDX 10 mg/kg) e reversão (pré-tratados durante 7 dias com LDX e posteriormente tratados com CVD, VAL e Salina) tiveram os níveis de glutationa reduzida (GSH) e de peroxidação lipídica (TBARS) determinados nas áreas cerebrais do córtex pré-frontal (PFC) e corpo estriado (CE) e o fator neurotrófico derivado do cérebro (BDNF) no hipocampo (HC). Os resultados indicaram que o CVD preveniu e reverteu a hiperlocomoção e comprometimento da interação social induzidas por LDX. Na avaliação neuroquímica o CVD foi capaz de aumentar prevenir e reverter as alterações nos níveis de GSH, BDNF e peroxidação lipídica dos animais submetidos ao modelo de mania com resultados comparáveis aos dos animais tratados com VAL e controles. Em conclusão, os resultados deste estudo revelaram que o CVD é um fármaco em potencial para o tratamento da mania, sendo indicados, portanto, estudos clínicos que comprovem a ação deste fármaco.
39
Frey, Benício Noronha. "Desenvolvimento de um modelo animal de mania : correlação com marcadores bioquímicos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2006. http://hdl.handle.net/10183/8169.
Full textAbstract:
Embora há muito tempo se considere que alterações neurobiológicas tenham um papel central no transtorno bipolar (TB), os mecanismos moleculares ligados à sua fisiopatologia permanecem desconhecidos. A hipótese atual sugere que alterações nos circuitos cerebrais associados à regulação do humor e alterações em sistemas de sinalização intracelular associados à plasticidade e sobrevivência neuronal estão envolvidas no TB. Modelos animais são ferramentas úteis que nos permitam testar estas hipóteses e a resposta aos agentes farmacológicos. Um dos mais bem estabelecidos modelos animais de mania é o de hiperatividade induzida por psicoestimulantes. Portanto, o objetivo dos nossos estudos foi desenvolver um modelo animal de mania avaliando os efeitos do tratamento agudo e crônico com d-anfetamina (ANF) na atividade locomotora em ratos Wistar adultos. Em paralelo, nós investigamos o estresse oxidativo induzido pela ANF no córtex pré-frontal (CPF), hipocampo (HIPO) e estriado. A atividade locomotora foi avaliada através do teste de campo aberto e o malondialdeído (TBARS), proteinas carbonila, superóxido dismutase (SOD) e a catalase (CAT) foram usados como parâmetros de estresse oxidativo. O uso agudo e crônico de ANF aumentou a atividade locomotora e induziu um estado de estresse oxidativo no CPF, HIPO e estriado. Além disso, o tratamento crônico com ANF aumentou a formação de superóxido e TBARS em partículas submitocondriais no CPF e HIPO. Em conjunto, estes resultados sugerem que o tratamento crônico com ANF induz hiperatividade e aumenta o estresse oxidativo no cérebro de ratos. Em uma segunda etapa, estudamos se os estabilizadores de humor litio (Li) e valproato (VPT) previnem e revertem a hiperatividade e as alterações dos marcadores bioquímicos induzidos pela ANF no HIPO de ratos. Com este modelo, observamos que o Li e o VPT reverteram e preveniram a hiperatividade e o estresse oxidativo induzidos pela ANF. Ainda, observamos que o Li e o VPT aumentaram o fator neurotrófico derivado do cérebro e que este efeito pode estar envolvido com o comportamento locomotor. Entretanto, embora o Li tenha aumentado o fator de crescimento neural no HIPO dos ratos, este efeito foi independente ao comportamento locomotor. Nós também estudamos os níveis de SOD, CAT, TBARS e o dano em DNA no soro de duas gemas monozigóticas durante episódio maníaco. As gêmeas bipolares apresentaram elevação em SOD, TBARS e dano ao DNA e redução da CAT que o controle. Os níveis de SOD e de TBARS normalizaram após o tratamento com Li e antipsicóticos. Estes achados estão de acordo com os resultados do modelo animal e indicam que o estresse oxidativo pode estar associado à fisiopatologia do TB. Em conclusão, nossos estudos sugerem que nosso modelo animal apresenta uma boa validade aparente, interpretativa e preditiva como um modelo animal de mania.Although it has long been considered that neurobiological changes play a critical role in bipolar disorder (BD), the molecular mechanisms underlying its pathophysiology remain largely unknown. Current hypothesis suggests that changes within the brain circuits associated with mood regulation, and altered intracellular signaling system associated with neuronal plasticity and survival are involved in BD. Animal models are useful tools that allow us to test these hypotheses and the response to pharmacological agents. One of the best established animal models of mania is the psychostimulant-induced hyperactivity. Therefore, the aim of our studies was to develop an animal model of mania assessing the effects of acute and chronic treatment of d-amphetamine (AMPH) on locomotor activity in adult Wistar rats. In parallel, we investigated AMPH-induced oxidative stress in the prefrontal cortex (PFC), hippocampus (HIPPO), and striatum. Locomotor activity was assessed using the open field test and malondialdehyde (TBARS), protein carbonyl, superoxide dismutase (SOD), and catalase (CAT) were used as oxidative stress parameters. Acute and chronic AMPH exposure increased the locomotor activity and induced an oxidative stress status in the PFC, HIPPO, and striatum. Moreover, chronic AMPH treatment increased superoxide and TBARS formation in submitochondrial particles in the PFC and HIPPO. Taken together, these results suggest that chronic AMPH treatment induces hyperactivity and increased oxidative stress in rat brain. As a second step we studied whether the mood stabilizers lithium (Li) and valproate (VPT) prevent and reverse AMPH-induced hyperactivity and changes in biochemical markers in rat HIPPO. Using this model, we observed that Li and VPT reversed and prevented AMPH-induced hyperactivity and oxidative stress. Further, we found that Li and VPT increased brain-derived neurotrophic factor, and that this effect may be associated with the locomotor behavior. However, although Li was able to increase nerve growth factor level in rat HIPPO, this effect was independent on locomotor behavior. We also studied serum SOD, CAT, TBARS, and DNA damage levels in two monozygotic twins during a manic episode. The bipolar twins had higher SOD, TBARS and DNA damage, and lower CAT than the control. SOD and TBARS levels were normalized after treatment with Li and antipsychotics. These findings are in accordance with the results from the animal model, and further indicate that oxidative stress may be associated with the pathophysiology of BD. In conclusion, our studies suggest that our model presents adequate face, construct, and predictive validity as an animal model of mania.
40
Vaidyanathan, Mani. "Compact models for the high-frequency characteristics of modern bipolar transistors." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0004/NQ38992.pdf.
Full text
41
Alnahar, Mouaz. "Comportement de l'IGBT en régime extrême." Grenoble INPG, 1999. http://www.theses.fr/1999INPG0050.
Full textAbstract:
Un systeme utilisant l'electronique de puissance performant et fiable exige des semi-conducteurs de puissance performants non seulement en regime normal mais aussi en regime extreme. Le travail presente est une contribution a l'etude comportementale de l'igbt en regime extreme. Cette etude permet de determiner les limites electriques et thermiques au niveau de la puce de l'igbt au dela desquelles le composant risque d'etre incapable d'assumer correctement sa fonction, ou bien le processus de defaillance est inevitable et elle est abordee dans la plupart des cas par la modelisation simplifiee avec verification experimentale destructive. Le premier chapitre fait un bref resume des travaux de recherche effectues a l'esim sur l'etude comportementale de l'igbt en regime normal. Le deuxieme chapitre est une analyse permettant d'estimer la capacite en densite de courant impulsionnel de l'igbt en tenant compte de la tenue en tension de grille v#g#s#m#a#x, de la saturation de courant du canal en fonction de v#g#s et du phenomene de latch-up. Dans le troisieme chapitre nous proposons deux modeles thermiques simplifies qui permettent d'evaluer avec des precisions suffisantes la temperature maximale dans le silicium en cas de court-circuit. Une methode electrothermique simple pour la determination de la duree maximale du court-circuit en fonction des conditions reelles est egalement proposee. Le quatrieme chapitre etudie le processus d'avalanche a tres forte densite de puissance par le depassement du champ electrique critique a partir d'une analyse unidimensionnelle de la physique interne. Nous proposons egalement dans ce chapitre deux aires de securite extremes en regime impulsionnel qui prennent en compte les limites electriques et thermiques, et la technologique de l'igbt. Dans le dernier chapitre nous illustrons l'exploitation des caracteristiques en regime extreme de l'igbt a travers la conception d'un ecreteur actif.
42
Pasquale, Antonio Maria Sexto Ysaias Delgado de. "Existência de pares \"d-wave\" e ondas de densidade em uma classe de modelos microscópicos para supercondutores com alta temperatura de transição." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-03052018-150652/.
Full textAbstract:
Os supercondutores de alta temperatura crítica apresentam propriedades diferentes dos supercondutores convencionais, uma destas propriedades importantes é a simetria não isotrópica do parâmetro de ordem. Neste trabalho se apresenta um modelo que mostra a presença de simetria d-wave em uma classe de supercondutores de alta Tc, assim como a condição para a existência de ondas de densidade nos estados de equilíbrio. Se analisa primeiro um sistema de três corpos, um bipolaron e dois elétrons, com o objetivo de estudar o efeito da repulsão coulombiana local e não local sobre a simetria do parâmetro de ordem para o caso exato e também o limite de acoplamento forte. Se mostra também a construção de um Hamiltoniano efetivo que desacopla a interação el etron-bipolaron com o fim de abordar o problema coletivo de infinitos corpos e vemos como o modelo proposto prediz a formação de ondas de densidade para uma região especifica dos parâmetros físicos do Hamiltoniano estudado.High-temperature superconductors have different properties than conventional superconductors, one of these important properties is non-isotropic symmetry of the order parameter. In this work we present a model that shows the presence of symmetry d-wave in a class of superconductors of high Tc , as well as the condition for the existence of density waves in the states of equilibrium. We first analyze a three-body system, a bipolaron and two electrons, in order to study the effect of local and non-local Coulomb repulsion on the symmetry of the order parameter for the exact case and also the strong coupling limit. It is also shown the construction of an effective Hamiltonian that decouples the electron-bipolaron interaction in order to approach the collective problem of infinite bodies and we see how the proposed model predicts the formation of density waves for a specific region of the physical parameters of the studied Hamiltonian.
43
Промович, Юрій Бориславович, Юрий Бориславович Промович, and Y. B. Promovych. "Математичне моделювання струму в об’єктах з неоднорідностями та методи їх біполярної електроімпедансної томоґрафії з підвищеною точністю." Thesis, Тернопільський національний технічний університет ім. Івана Пулюя, 2013. http://elartu.tntu.edu.ua/handle/123456789/2393.
Full textAbstract:
Роботу виконано в Тернопільському національному технічному університеті імені Івана Пулюя, Міністерства освіти і науки України.
Захист відбувся в 2013 р. в на засіданні спеціалізованої вченої ради К 58.052.01 в Тернопільському національному технічному університеті імені Івана Пулюя (46001, м. Тернопіль, вул. Руська, 56, ауд. 79).
З дисертацією можна ознайомитися у науково-технічній бібліотеці Тернопільського національного технічного університету імені Івана Пулюя (46001, м. Тернопіль, вул. Руська, 56).В дисертації розв’язано наукову задачу удосконалення математичної моделі траєкторій струму в м’яких тканинах з новоутвореннями для отримання достатньої точності реконструкції розподілу електричної провідності за даними біполярної ЕІТ. Для цього використано апріорні відомості про параметри тканин, а також введено поправку систематичної похибки вимірювання напруг. Встановлено, що відомі методи реконструкції розподілу провідності, які використовують зворотне проектування, не враховують взаємодії електричного струму з неоднорідним за провідністю середовищем. Для біполярної електроімпедансної томоґрафії побудовано метод реконструкції зображення, який полягає у зворотному проектуванні проекційних даних уздовж ліній максимальної густини електричного струму. Також побудовано модель систематичної похибки вимірювання електричного імпедансу томоґрафом для формування поправки, ефективність застосування якої підтверджена на реальних даних ТЕ. Метод реконструкції та модель систематичної похибки верифіковано з використанням імітаційної моделі та експериментального макета системи для електроімпедансної томоґрафії, побудованого на кафедрі «Біотехнічні системи» ТНТУ. Математичні моделі застосовано при побудові алґоритмів реконструкції, натурного та імітаційного моделювання ЕІТ.
В диссертации решено научную задачу усовершенствования математической модели траекторий тока в мягких тканях с новообразованиями с целью получения достаточной точности реконструкции распределения электрической плотности за данными биполярной электроимпедансной томографии (ЭИТ). Для этого использовано априорные данные о параметрах тканей, а также введено поправку систематической ошибки измерения напряжений. Установлено, что известные методы реконструкции, которые используют интегральные преобразования, не учитывают взаимодействия электрического тока с неоднородной за проводимостью средой. Для биполярной ЭИТ построено метод реконструкции изображения, в котором обратное проецирование осуществляется вдоль линий максимальной плотности электрического тока. Также построено математическую модель поправки систематической ошибки измерения электрического импеданса томографом для формирования поправки, эффективность использования которой подтверждена на реальных данных ТЭ. Для метода реконструкции и модели систематической ошибки провели верификацию с использованием компьютерной имитационной модели и экспериментального макета системы для ЭИТ, разработанного на кафедре «Биотехнические системы» ТНТУ. Математические модели использовано при построении алгоритмов реконструкции и имитационного моделирования ЭИТ.
The dissertation is focused on the improvement of methods and means of mathematical and computer modeling of image reconstruction in bipolar electrical impedance tomography (EIT). For a bipolar electrical impedance tomography the method of reconstruction of image is improved. This back projection along the lines of maximal electric current density method is used. The reconstruction method can be divided into three stages. The first stage of the method is the construction of the electric potential field for an empiric environment . Electric potential for the pair electrodes and is finded from the differential equation , , , , n – normal vector to boundary ; ( ) and ( ) - places of electrodes connected. On the second stage for every electrodes pair we build the line of the maximal electric current density. For the task of maximal current density line finding variations method was used. Along the maximal current density line in the area the power scattering is maximal and, assume, determine the difference potential between the electrodes pair. The realization of the third stage foresees the measured data filtration and back projection on an area . The mathematical model of an electrical impedance measurement systematic error of a tomograph is also worked up. The error of measurement in EIT contains the random and systematic components. The random component error by the insignificant electrode contact loss with the surface of a conducting body conditioned. A systematic error is the hardware features arrangement of a tomograph measurement transducer. As a rule every electrode to a measuring transducer of the impedance tomograph via one key such multiplexer is connected. When the resistance of a conducting body is approximately equal to resistance of a multiplexer open channel a substantial source of error is appear. The resistance of the opened channel of multiplexer is the source of the systematic error . The one realisation the tomographic experiment in the calibration mode as a is bounded stochastic sequence observable values of resistances -y pair of multiplexer keys ( ). The adequate model of signals from synchronous multiplexer systems is the stochastic sequence of class , which in the energy theory of casual signals. The estimation of the mathematical expectation of the stationary component and will be that functional for systematic error decreasing in tomographic experiment. Using of the energy theory of stochastic signals for the in-phase analysis of the ensemble of tomographic experiment realization a signal-error to build purpose as element of negative feedback for the input circuit of the impedance tomograph. Efficiency a mathematical model on the tomographic experiment (TE) real data confirms. For the method of reconstruction and model of systematic error verification with the use of imitation model and an experimental model system for electrical impedance tomography implemented. The model with a data as from a test conductivity distribution image of a flat section conducting body is used. The result of imitation design is a sequence of voltage falling values for each of formally certain pair of measuring electrodes. Experimental model system on a department "Biotechnical systems" of the Ternopil National Ivan Pul’uj Technical University designed. The constructed mathematical models for the realizing of the reconstruction algorithms and EIT imitation design are used.
44
Young, Jonathan T. D. "Self models in bipolar I disorder as implicity indexed by sentence completion." Thesis, University of East Anglia, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436031.
Full text
45
HARTIGAN, PATRICK MICHAEL. "OBSERVATIONS AND BOWSHOCK MODELS OF HERBIG-HARO OBJECTS (STAR FORMATION, BIPOLAR OUTFLOWS)." Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184022.
Full textAbstract:
Herbig-Haro (HH) objects are small nebulous regions of shock excited gas associated with bipolar outflows from newly formed stars. This dissertation presents an extensive set of observational data on Herbig-Haro objects, including deep CCD images, medium resolution long-slit spectra, and high resolution echelle spectra. The CCD survey indicates that HH objects cannot be identified reliably on the basis of morphology alone. The spectral line data show that HH objects exhibit enormous linewidths even though the objects are only about 1500 AU in size. The spectra sometimes have two velocity peaks, and show spatial separation of the high and low radial velocity gas. A radiative bowshock model constructed from a series of planar shock models accounts for the large linewidths, unusual line profiles, line ratios, and spatial structure seen in HH objects. A simple formula is derived that relates the shock velocity and orientation angle of a radiating bowshock to the observed maximum and minimum radial velocities seen in a line profile. The bowshock forms around a 'bullet' of material ejected from the forming star. The most likely acceleration mechanism for the bullet seems to be a breakup of a collimated stellar jet.
46
Queiroz, Ana Isabelle de Gois. "Efeitos do dimesilato de lisdexanfetamina em ratos : relevância como modelo animal do episódio de mania." reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/5609.
Full textAbstract:
QUEIROZ, Ana Isabelle de Gois. Efeitos do dimesilato de lisdexanfetamina em ratos : relevãncia como modelo animal do episódio de mania. 2012. 83 f. Dissertação (Mestrado em Farmacologia) - Universidade Federal do Ceará. Faculdade de Medicina, Fortaleza, 2012.Submitted by denise santos (denise.santos@ufc.br) on 2013-08-13T13:35:38Z No. of bitstreams: 1 2012_dis_aigqueiroz.pdf: 797820 bytes, checksum: 27fbdbd9eed1ccebbe75429b2686e641 (MD5)
Approved for entry into archive by denise santos(denise.santos@ufc.br) on 2013-08-13T14:13:05Z (GMT) No. of bitstreams: 1 2012_dis_aigqueiroz.pdf: 797820 bytes, checksum: 27fbdbd9eed1ccebbe75429b2686e641 (MD5)
Made available in DSpace on 2013-08-13T14:13:05Z (GMT). No. of bitstreams: 1 2012_dis_aigqueiroz.pdf: 797820 bytes, checksum: 27fbdbd9eed1ccebbe75429b2686e641 (MD5) Previous issue date: 2012
O Transtorno Afetivo Bipolar é um transtorno mental severo que acomete cerca de 1,5% da população mundial e se caracteriza pela oscilação de humor entre a depressão e a mania, interferindo no desempenho do indivíduo em termos pessoais e profissionais, bem como sendo responsável por alto número de suicídios. Todos esses fatores o caracterizam como um problema de saúde pública. Seu mecanismo fisiopatológico ainda não é totalmente conhecido e o arsenal terapêutico atual ainda é escasso, necessitando de contínuas pesquisas nesse âmbito. Observando a necessidade de maior disponibilidade de modelos animais de mania para maiores pesquisas é que o estudo objetivou investigar um novo modelo animal de mania. O desenho experimental da pesquisa seguiu os critérios para determinar um modelo animal que são: a validade de face (onde busca-se mimetizar no animal comportamento característico na doença), validade de constructo (a fisiopatologia da doença) e a validade preditiva ( se os medicamentos já estabelecidos para determinada doença são capazes de reverter e prevenir os efeitos do fármaco que induz a patologia). Logo, o presente trabalho se propôs a investigar a atividade do Dimesilado de Lisdexanfetamina (LDX), pró-fármaco que ao ser metabolizado a d-anfetamina passa a exercer sua atividade psicoestimulante como possível agente em um modelo animal de mania. O tratamento com D-ANF induz hiperlocomoção e é considerado como um modelo animal de mania bipolar já estabelecido. Por isso, procurou-se determinar as alterações comportamentais e de estresse oxidativo induzidas pela administração via oral sub-crônica de LDX, bem como a reversão e prevenção deste efeito ao tratar os ratos com lítio, medicamento protótipo como estabilizante do humor. Um aumento significativo no comportamento locomotor foi induzido por LDX (10 e 30 mg/Kg). Para determinar os efeitos de Lítio (Li) nas alterações induzidas por LDX nos ratos do grupo reversão, o protocolo seguiu a administração de LDX (10 ou 30 mg / Kg) ou solução salina durante 14 dias. Entre os dias 8o e 14o os animais receberam Li (47,5 mg / kg, ip) ou solução salina. No protocolo de prevenção, os ratos foram pré-tratados com solução salina ou Li antes da administração de LDX. Os níveis de Glutationa Reduzida (GSH) e de peroxidação lipídica foram determinados no córtex pré-frontal (PFC), hipocampo (HC) e estriado (ST) de ratos. Constatou-se que o Lítio preveniu a hiperlocomoção induzida por LDX, nas doses de 10 e 30 mg/kg, mas somente reverteu a hiperlocomoção quando utilizada a dose de 10 mg/ kg de LDX. Além disso, ambas as doses de LDX diminuíram o conteúdo de GSH (em ST e PFC), enquanto que Li foi capaz de reverter e prevenir estas alterações, principalmente no PFC. LDX (10 e 30 mg / kg) aumentou a peroxidação lipídica, que foi revertida e prevenida por Li. Diante dos resultados em termos de hiperlocomoção e estresse oxidativo demonstrou-se que o LDX conseguiu induzir tais parâmetros, se mostrando como uma promessa de modelo animal alternativo de mania.
47
Steinberg, Julia. "Functional genomics analyses of neuropsychiatric and neurodevelopmental disorders." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:e47d1ac2-de92-47d8-864b-dac0bf6669e8.
Full textAbstract:
Recent large-scale genome-wide studies for many human disorders have identified associations with numerous genetic variants. The biological interpretation of these variants presents a major challenge. In particular, the identification of biological pathways underlying the association could provide crucial insights into the disease aetiologies. In this thesis, I used functional genomics approaches to increase our understanding of neuropsychiatric and neurodevelopmental disorders. Firstly, in an integrative analysis of autism spectrum disorder (ASD), I looked into the role of genes targeted by Fragile-X Mental Retardation Protein ("FMRP targets"). I found evidence that FMRP targets contribute to ASD via two distinct aetiologies: (1) ultra-rare and highly penetrant single disruptions of embryonically upregulated FMRP targets ("single-hit aetiology") or (2) the combination of multiple less penetrant disruptions of synaptic FMRP targets ("multiple-hit aetiology"). In particular, I developed a pathway-association test sensitive to multiple-hit aetiologies. Secondly, I carried out an integrative analysis of bipolar disorder, following up a previously identified association with long-term potentiation. The association was not consistent across independent SNP and CNV datasets. Thirdly, I addressed the difficulty in identifying functional relationships between genes by integrating different datasets into a gene functional-linkage network tuned to the nervous system ("NsNet"). NsNet identified functional links between the genes disrupted by de novo loss-of-function mutations in ASD and, separately, in schizophrenia probands more sensitively than a general functional-linkage network. Fourthly, I considered the challenge of interpreting the phenotypic impact of gene disruptions, focusing on the identification of haploinsufficient genes. I constructed a gene haploinsufficiency score based on genome-wide datasets. Compared to existing approaches, the new score performed better in identifying less-studied haploinsufficient genes. This work both extends the methodology to detect the contribution of genetic variation to neuropsychiatric disorders and also yields insights into the variant genes and the pathways that underlie them. Firstly, in an integrative analysis of autism spectrum disorder (ASD), I looked into the role of genes targeted by Fragile-X Mental Retardation Protein ("FMRP targets"). I found evidence that FMRP targets contribute to ASD via two distinct aetiologies: (1) ultra-rare and highly penetrant single disruptions of embryonically upregulated FMRP targets ("single-hit aetiology") or (2) the combination of multiple less penetrant disruptions of synaptic FMRP targets ("multiple-hit aetiology"). In particular, I developed a pathway-association test sensitive to multiple-hit aetiologies. Secondly, I carried out an integrative analysis of bipolar disorder, following up a previously identified association with long-term potentiation. The association was not consistent across independent SNP and CNV datasets. Thirdly, I addressed the difficulty in identifying functional relationships between genes by integrating different datasets into a gene functional-linkage network tuned to the nervous system ("NsNet"). NsNet identified functional links between the genes disrupted by de novo loss-of-function mutations in ASD and, separately, in schizophrenia probands more sensitively than a general functional-linkage network. Fourthly, I considered the challenge of interpreting the phenotypic impact of gene disruptions, focusing on the identification of haploinsufficient genes. I constructed a gene haploinsufficiency score based on genome-wide datasets. Compared to existing approaches, the new score performed better in identifying less-studied haploinsufficient genes. This work both extends the methodology to detect the contribution of genetic variation to neuropsychiatric disorders and also yields insights into the variant genes and the pathways that underlie them.
48
Ruiz, Palmero José Miguel. "Physical InP-based HBT models for ultimate digital circuit optimization /." Konstanz : Hartung-Gorre, 2006. http://www.loc.gov/catdir/toc/fy0710/2007385696.html.
Full text
49
Martin, Hugo. "Optimisation multi-objectifs et élicitation de préférences fondées sur des modèles décisionnels dépendants du rang et des points de référence." Electronic Thesis or Diss., Sorbonne université, 2022. http://www.theses.fr/2022SORUS101.
Full textAbstract:
Cette thèse se situe dans le cadre de la théorie de la décision algorithmique, domaine de recherche à l'intersection de la théorie de la décision, de l'intelligence artificielle et de la recherche opérationnelle. Nous nous intéressons à la prise en compte de comportements sophistiqués dans des environnements complexes (décision multicritère, décision collective, décision dans le risque et l'incertain). Nous proposons d'abord des méthodes d'optimisation multi-objectifs sur domaine implicite lorsque les préférences sont représentées par des modèles dépendants du rang (intégrale de Choquet, bipolar OWA, Cumulative Prospect Theory et intégrale de Choquet bipolaire). Ces méthodes reposent sur des approches de programmation mathématique et d'algorithmique discrète. Ensuite, nous présentons des méthodes d'élicitation incrémentale des paramètres de modèles dépendants du rang permettant de prendre en compte la présence d'un point de référence dans les préférences d'un décideur (bipolar OWA, Cumulative Prospect Theory, intégrale de Choquet avec capacités et bicapacités). Finalement, nous abordons la modification structurelle de solutions sous contraintes (coût, qualité) dans des méthodes de tri à plusieurs points de référence. Les différentes approches proposées dans cette thèse ont été testées et nous présentons les résultats numériques obtenus afin d'illustrer leur efficacité pratiqueThis thesis work falls within the research field of algorithmic decision theory, which is defined at the junction of decision theory, artificial intelligence and operations research. This work focuses on the consideration of sophisticated behaviors in complex decision environments (multicriteria decision making, collective decision making and decision under risk and uncertainty). We first propose methods for multi-objective optimization on implicit sets when preferences are represented by rank-dependent models (Choquet integral, bipolar OWA, Cumulative Prospect Theory and bipolar Choquet integral). These methods are based on mathematical programming and discrete algorithmics approaches. Then, we present methods for the incremental parameter elicitation of rank-dependent model that take into account the presence of a reference point in the decision maker's preferences (bipolar OWA, Cumulative Prospect Theory, Choquet integral with capacities and bicapacities). Finally, we address the structural modification of solutions under constraints (cost, quality) in multiple reference point sorting methods. The different approaches proposed in this thesis have been tested and we present the obtained numerical results to illustrate their practical efficiency
50
Zhu, Chendong. "The mixed-mode reliability stress of Silicon-Germanium heterojunction bipolar transistors." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14647.
Full textAbstract:
The objective of the dissertation is to combine the recent Mixed-Mode reliability stress studies into a single text. The thesis starts with a review of silicon-germanium heterojunction bipolar transistor fundamentals, development trends, and the conventional reliability stress paths used in industry, after which the new stress path, Mixed-Mode stress, is introduced. Chapter 2 is devoted to an in-depth discussion of damage mechanisms that includes the impact ionization effct and the selfheating effect. Chapter 3 goes onto the impact ionization effect using two-dimensional calibrated MEDICI simulations. Chapter 4 assesses the reliability of SiGe HBTs in extreme temperature environments
by way of comprehensive experiments and MEDICI simulations. A comparison of the device
lifetimes for reverse-EB stress and mixed-mode stress indicates different damage mechanisms
govern these phenomena. The thesis concludes with a summary of the project and suggestions for
future research in chapter 5.