O diabetes mellitus (DM) pode levar à disfunção das glândulas salivares. A ativação do receptor de produtos finais de glicosilação avançada e de seus ligantes tem sido reportado em várias doenças crônicas, entre estas, a diabetes e suas complicações. Este estudo analisou a expressão do RAGE, proteína do grupo de alta mobilidade B1 (HMGB1) e de produtos de glicosilação avançada (AGE), bem como os efeitos da irradiação com laser de baixa potência (ILBP) em glândulas salivares submandibulares (GSMs) de ratas diabéticas. Ratas Wistar com 12 semanas de vida foram divididas em 3 grupos: controle (C), diabético (D) e diabético com laser (DL). A indução de DM nos grupos D e DL foi realizada com injeção intraperitoneal de estreptozotocina 60 mg/kg de peso corporal, no 1° dia experimental. No 29°dia, os animais do grupo DL receberam a ILBP (660 nm, 70 mW, 20 J/cm² e 0,56 J por ponto), aplicado no total de quarenta pontos cobrindo a área correspondente as GSMs, e os seus efeitos foram avaliados 24 h após a irradiação (eutanásia). As análises de parâmetros metabólicos, histológicos e de marcadores de inflamação, apoptose e proliferação foram realizadas. Nossos achados mostram que a ILBP diminuiu a glicemia das ratas diabéticas irradiadas, melhorando a resistência à insulina (HOMA-IR), sensibilidade à insulina (HOMA-IS) e função de células beta (HOMA-?). Em GSM, o DM parece aumentar a expressão do eixo HMGB1/AGE/RAGE, possivelmente associado à ativação do fator de transcrição nuclear kappa B (NF?B). A ILBP reduziu os marcadores de inflamação, HMGB1 e TNF-? em GSM de ratas diabéticas, e parece regular a expressão de proteínas relacionadas à proliferação e à apoptose, pela via do AMP cíclico, parcialmente mediado por proteína kinase regulada por sinais extracelulares. No entanto, mais estudos são necessários para melhor entender os efeitos do laser neste tecido. / Diabetes (DM) can lead to dysfunction of the secretory capacity in salivary glands. Since the activation of the receptor for advanced glycation end-products (RAGE) and its ligands has been suggested to participate in chronic disorders, such as diabetes and its complications. This study analyzed the expression of RAGE, high mobility group box protein B1 (HMGB1) and advanced glycation end-products (AGEs) were evaluated, as well as the effects of low-power laser irradiation (ILBP), in diabetic submandibular glands (GSM). Wistar rats 12 weeks-old were divided in three groups: control (C), diabetic (D) and diabetic with laser (DL). The D and DL rats were intraperitoneally injected with streptozotocin 60 mg/kg, in the 1st experimental day. On the 29° day, the DL rats received the ILBP (660 nm, 70 mW, 20 J/cm² e 0,56J per point), with a total of forty points covering the GSMs area, its effects were evaluated 24h after irradiation (euthanasia). Metabolic parameters, histology and the inflammatory, apoptosis and proliferation markers were evaluated. Our findings show that ILBP reduced the blood glucose levels of the irradiated diabetic rats, improving their insulin resistance (HOMA-IR), insulin sensitivity (HOMA-IS) e beta cell function (HOMA-?). In GSM, DM seems to upregulate the expression of HMGB1/AGE/RAGE axis, possibly associated with the activation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF?B). The ILBP reduced the inflammatory markers HMGB1 and TNF-? in diabetic GSM, and seems to regulate the expression of proteins related to proliferation and apoptosis, by cyclic AMP pathway, partially mediated by extracellular signal-regulated kinase. However, more studies are necessary to better understand the laser effects on this tissue.

O trabalho trata do projeto e do desenvolvimento de um processador de baixo consumo de potência, de forma simplificada, explorando técnicas de microarquitetura, para atingir menor consumo de potência. É apresentada uma sequência lógica de desenvolvimento, a partir de conceitos e estruturas básicas, até chegar a estruturas mais complexas e, por fim, mostrar a microarquitetura completa do processador. Esse novo modelo de processador é comparado com estudos prévios de três processadores, sendo o primeiro modelo síncrono, o segundo assíncrono e o terceiro uma versão melhorada do primeiro modelo, que inclui minimizações de registradores e circuitos. Uma nova metodologia de criação de padring de microcontroladores, baseada em reuso de informações de projetos anteriores, é apresentada. Essa nova metodologia foi criada para a rápida prototipagem e para diminuir possíveis erros na geração do código do padring. Comparações de resultados de consumo de potência e área são apresentadas para o processador desenvolvido e resultados obtidos com a nova metodologia de geração de padring também são apresentados. Para o processador, um modelo, no qual se utilizam múltiplos barramentos para minimizar o número de ciclos de máquina por instrução, é apresentado. Também foram ressaltadas estruturas que podem ser otimizadas e circuitos que podem ser reaproveitados para diminuir a quantidade de circuito necessário na implementação. Por fim, a nova implementação é comparada com os três modelos anteriores; os ganhos obtidos de desempenho com a implementação dessas estruturas foram de 18% que, convertidos em consumo de potência, representam economia de 13% em relação ao melhor caso dos processadores comparados. A tecnologia utilizada no desenvolvimento dos processadores foi CMOS 250nm da TSMC. / This work is a development and implementation of a low power processor in a simplified way, exploring microarchitecture techniques to achieve low power consumption. A logic sequence of design flow is presented, starting from basic concepts and circuit structures incrementing these concepts and structures to achieve a complex microarchitecture of a processor. A new methodology for microcontroller padring creations based in reuse of previous project information is presented. This new methodology was developed for fast prototyping and decreases the possible error in generation of microcontroler padring code creation. This new microarchitecture is compared with three previous processors, one is an original synchronous version, the second is an asynchronous version, and the third is based on the first model with register and circuit minimizations. Results of area and power consumption are compared with this new proposed architecture. The new model uses multiple buses with access timing tuned for different internal blocks. This timing tuning decrease the number of machine cycle necessary per instruction. In addition, it presents some macro block circuit partition and circuit reuse to minimize the circuit necessary for implementation. The gain obtained in performance with these new structures was 18%, converting to power consumption, it represent a decrease in 13% in relation with the best of three processor compared. The technology used in the development of these processors was CMOS 250nm from TSMC.

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No. of bitstreams: 1 luciajanuariodosanjos.pdf: 2619797 bytes, checksum: 9cd633cb6127c04853743312e85b9a1c (MD5) Previous issue date: 2016-02-26 / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A artrite é uma desordem músculo esquelética, caracterizada por inflamação das articulações e que apresenta importante impacto socioeconômico, uma vez que é observada em diversas patologias reumáticas, como na artrite reumatóide (AR), doença autoimune crônica, associada à incapacidade motora e laboral dos pacientes. As estratégias atuais para o tratamento da AR objetivam o alívio dos sintomas e modificação do curso degenerativo da doença, mas podem apresentar sérios efeitos colaterais e nem sempre resultam em melhora clínica. Neste contexto, a utilização de laser de baixa potência surge como alternativa não invasiva para o tratamento da artrite, devido as suas propriedades anti-inflamatórias e de regeneração tecidual. Entretanto, os mecanismos anti-inflamatórios do laser nos tecidos biológicos ainda não estão completamente conhecidos. Assim, o presente estudo tem por objetivo avaliar os efeitos anti-inflamatórios de lasers terapêuticos de baixa potência num processo inflamatório induzido, o qual se assemelha a AR. Para isso, um processo inflamatório foi induzido nas articulações talocrural e subtalar dos dois membros posteriores de camundongos C57BL/6, utilizando uma injeção de zymosan na região periarticular. Os animais foram divididos em 8 grupos (n=6): (I) controle, (II) zymosan, (III) eutanasiado 5h após indução com zymosan, (IV) zymosan+dexametasona, (V) laser 3J/cm2, (VI) laser 30J/cm2, (VII) zymosan+laser 3J/cm2, (VIII) zymosan+laser 30J/cm2. As condições do laser de baixa potência foram: λ=830nm (infravermelho), potência 10mW e fluências de 3J/cm2 e 30J/cm2, no modo contínuo de emissão da luz. A irradiação foi realizada durante 4 dias consecutivos, iniciando 5 horas após a indução a inflamação pelo zymosan. Vinte quatro horas após a última aplicação do laser, os animais foram eutanasiados e suas articulações encaminhadas para as seguintes análises: (a) análise morfológica, (b) análise de fragmentação de DNA por TUNEL e (c) análise da expressão de genes que codificam proteínas relacionadas às vias apoptóticas por PCR em tempo real. As análises morfológicas revelaram à presença de infiltrado celular inflamatório no tecido conjuntivo adjacente a região periarticular, em todos os grupos que receberam zymosan. Esse infiltrado diminuiu consideravelmente após a irradiação do laser na fluência de 30J/cm2. Para os dois grupos irradiados com laser, observou-se a elevação na taxa de apoptose somente nas células do infiltrado inflamatório, resultado este corroborado pelo aumento da expressão de genes que codificam proteínas associadas tanto pela via extrínseca como pela via intrínseca da apoptose. A resolução do processo inflamatório para o grupo Zy+3J/cm2 foi mais lenta do que a observada no grupo Zy+30J/cm2, uma vez que, após o término do tratamento, foram observadas elevada densidade celular e taxa de fragmentação de DNA nas células inflamatórias. Com isso, o laser de baixa potência, em especial na fluência de 30J/cm2, foi capaz de reduzir o infiltrado inflamatório na região periarticular, acelerando o processo apoptótico dessas células. A utilização do laser infravermelho de baixa potência pode ser uma boa alternativa para o tratamento de desordens inflamatórias articulares, uma vez que é um método não invasivo. Adicionalmente, esse tipo de tratamento não demonstrou efeitos colaterais nos demais tecidos adjacentes sadios, atuando especialmente nas células inflamatórias. / Arthritis is a muscle skeletal disorder characterized by inflammation of the joints, which has a significant socioeconomic impact, as observed in various rheumatic disorders such as rheumatoid arthritis (RA), chronic autoimmune disease associated with patients motor incapacity. Current strategies for the treatment of RA aim to relieve symptoms and modifying the degenerative course of the disease, but may have serious side effects and not always result in clinical improvement. In this context, the use of low-power laser therapy appears as non-invasive alternative for the arthritis treatment due to their anti-inflammatory and tissue regeneration properties. However, the anti-inflammatory mechanisms of the laser in biological tissues are not completely understood. Thus, this study aims to evaluate the anti-inflammatory effects of therapeutic low-power lasers in an induced inflammatory process, which resembles RA. An inflammatory process was induced in the talocrural and subtalar joints of the two rear paws of C57BL/6 using a zymosan injection in the periarticular region. The animals were divided into 8 groups (n = 6): (I) control, (II) zymosan, (III) euthanized 5 hours after induction with zymosan (IV) zymosan + dexamesona, (V) laser 3J/cm2 (VI ) laser 30J/cm2 (VII) + zymosan laser 3J/cm2 (VIII) laser zymosan + 30J/cm2. The low power laser conditions were: λ = 830 nm (infrared), 10mW power and fluences of 3 J/cm2 and 30J/cm2 at continuous mode of light emission. Irradiation was carried out for 4 consecutive days, starting 5 hours after inflammation-induced by zymosan. Twenty four hours after the last application of the laser, the animals were euthanized, their joints dissected and distributed: (a) morphological analysis, (b) DNA fragmentation analysis by TUNEL and (c) expression analysis of genes encoding proteins related to apoptotic pathways by real time PCR. Morphological analysis revealed the presence of inflammatory cell infiltrate in the adjacent connective tissue of periarticular region for all groups that received zymosan. This infiltration decreased significantly after laser irradiation using 30J/cm2 fluence. Both groups irradiated demonstrated DNA fragmentation rate incresed and only observed in inflammatory cells. DNA fragmentation is usually observed to cell death by apoptosis. This result is corroborated by expression increase of genes that encode proteins associated with both intrinsic and extrinsic pathways of apoptosis. The inflammatory process resolution for Zy+3J/cm2 group was slower than Zy+30J/cm2, since it was observed high cell density and DNA fragmentation rate in inflammatory cells. Thus, the low-power laser, particularly in 30J/cm2 fluence, could reduce the inflammatory infiltration in periarticular area, accelerating the inflammatory cells apoptosis. The use of low power infrared laser can be a good alternative for inflammatory joint disorders treatment, since it is a noninvasive method. Additionally, this type of treatment did not show side effects on other healthy surrounding tissues, acting especially in inflammatory cells.

The recent advancements in the communication area have enabled the Internet of Things, a paradigm which extends the Internet to everyday objects. The Internet of Things enables many new applications, but also comes with great challenges; effective communication under limited power supply being the perhaps most important one. This thesis presents the design, implementation, and evaluation of an energy-efficient handover algorithm for the main building block in the creation of the Internet of Things: wireless sensor networks. Our low-power handover design is based on a careful breakdown and analysis of the potential power consumption of different components of the handover process. With the scanning part of the process being identified as the main drain of energy, the algorithm is designed to place the majority of the scanning responsibility on the mains powered access points, rather than on the low-power mobile nodes. The proposed algorithm has been implemented and its functionality and low power consumption have been empirically evaluated. We show that the design can reduce the energy consumption by several orders of magnitude compared to existing handover algorithms for wireless sensor networks. In addition, interesting fading effects were discovered in a sparsely deployed network scenario with limited access point coverage; most likely due to multipath propagation. For this case the handover performance was greatly reduced, relative our more normal coverage scenario. While these results illustrate that the absolute energy savings will differ from scenario to scenario, the potential energy savings made possible by the proposed algorithm significantly reduce the battery requirements of the devices in the emerging landscape of the Internet of Things; potentially even opening the door for new devices to connect.

The rising power demands and cost motivates us to explore low power solutions in electronics. In nanometer Complementary Metal Oxide Semiconductor (CMOS) processes with low threshold voltages and thin gate oxides, subthreshold leakage power dominates total power of a circuit. As technology scales, Negative Bias Temperature Instability (NBTI) emerged as a major limiting reliability mechanism. It causes a threshold voltage shift which, over time, results in circuit performance degradation. Hence, leakage power and NBTI degradation are two key challenges in deep sub micron regime. In this dissertation, interval arithmetic based interval propagation technique is introduced as an effective leakage optimization technique in high level circuits with little overhead. The concept of self similarity from fractal theory is adopted for the first time in VLSI research to handle large design space. Though there are some leakage and NBTI co-optimization techniques in literature, our vector cycling approach combined with a back tracking algorithm have achieved better results for ISCAS85 benchmarks. We did not find any previous research works on NBTI optimization of finite state machines (FSMs). The optimization techniques of NBTI optimization in FSMs is introduced in this dissertation as well and substantial NBTI optimization is reported. Input vector control has been shown to be an effective technique to minimize subthreshold leakage. Applying appropriate minimum leakage vector (MLV) to each register transfer level (RTL) module instance results in a low leakage state with significant area overhead. For each module, via Monte Carlo simulation, we identify a set of MLV intervals such that maximum leakage is within (say) 10% of the lowest leakage points. As the module bit width increases, exhaustive simulation to find the low leakage vector is not feasible. Further, we need to search the entire input space uniformly to obtain as many low leakage intervals as possible. Based on empirical observations, we observed self similarity in the leakage distribution of adder/multiplier modules when input space is partitioned into smaller cells. This property enables uniform search of low leakage vectors in the entire input space. Also, the time taken for characterization increases linearly with the module size. Hence, this technique is scalable to higher bit width modules with acceptable characterization time. We can reduce area overhead (in some cases to 0) by choosing Primary Input (PI) MLVs such that resultant inputs to internal nodes are also MLVs. Otherwise, control points can be inserted. Based on interval arithmetic, given a DFG, we propose a heuristic with several variations for PI MLV identification with minimal control points. Experimental results for DSP filters simulated in 16nm technology demonstrated leakage savings of 93.8% with no area overhead, compared to existing work. Input vector control can also be adopted to reduce NBTI degradation as well as leakage in CMOS circuits. In the prior work, it is shown that minimum leakage vector of a circuit is not necessarily NBTI friendly. In order to achieve NBTI and leakage co-optimization, we propose an input vector cycling technique which applies different sub-optimal low leakage vectors to primary inputs at regular intervals. A co-optimal input vector for a given circuit is obtained by using simulated annealing (SA) technique. For a given input vector, a set of critical path PMOS transistors are under stress. A second input vector is obtained using a back tracking algorithm such that most of the critical path PMOS transistors are put in recovery mode. When a co-optimized input vector is assigned to primary input, critical path nodes under stress with high delay contribution are set to recovery. Logic 1 is back propagated from the nodes to the primary inputs to obtain the second input vector. These two vectors are alternated at regular time intervals. The total stress is evenly distributed among transistor sets of two vectors, as the intersection of the two sets is minimized. Hence, the overall stress on critical path transistors is alleviated, thereby reducing the NBTI delay degradation. For ISCAS85 benchmarks, an average of 5.3% improvement is achieved in performance degradation at 3.3% leakage overhead with NBTI-leakage co-optimization with a back tracking algorithm compared to solely using co-optimization. A 10.5% average NBTI improvement is obtained when compared to circuit with minimum leakage input vector for 18% average leakage overhead. Also, an average NBTI improvement of 2.13% is obtained with 6.77% leakage improvement when compared to circuit with minimum NBTI vector. Vector cycling is shown to be more effective in mitigating NBTI over input vector control. Several works in the literature have proposed optimal state encoding techniques for delay, leakage, and dynamic power optimization. In this work, we propose, for the first time, NBTI optimization based on state code optimization. We propose a SA based state code assignment algorithm, resulting in minimization of NBTI degradation in the synthesized circuit. A PMOS transistor when switched ON for a long period of time, will lead to delay degradation due to NBTI. Therefore, in combinational circuits, an NBTI friendly input vector that stresses the least number of PMOS transistors on the critical path can be applied. For sequential circuits, the state code can significantly influence the ON/OFF mode of PMOS transistors in the controller implementation. Therefore, we propose to focus on state encoding. As the problem is computational intractable, we will focus on encoding states with high state probability. The following SA moves are employed: (a) code swap; and (b) code modification by flipping bits. Experiments with LGSYNTH93 benchmarks resulted in 18.6% improvement in NBTI degradation on average with area and power improvements of 5.5% and 4.6% respectively.

Techniques for adapting metamaterials for the improvement of RF energy harvesting and infrared photodetection are demonstrated using experimental and computer simulation methods. Two methods for RF energy harvesting are experimentally demonstrated and supported by computer simulation. In the first method, a metamaterial perfect absorber (MPA) is made into a rectenna capable of harvesting RF energy and delivering power to a load by soldering Schottky diodes onto connected split ring resonator (SRR) structures composing the planar metasurface of the perfect absorber. The metamaterial rectenna is accompanied by a ground plane placed parallel to it, which forms a Fabry-Perot cavity between the metasurface and the ground plane. The Fabry-Perot cavity stores energy in the form of standing waves which is transferred to the SRR structures of the metasurface as AC currents that are rectified by the diodes to create DC power. This type of design enables highly efficient energy harvesting for low input power, creates a large antenna capture area, and uses elements with small electrical size, such that 100 uW of power (enough to operate simple devices) can be captured at ambient intensities ~ 1 - 2 uW/cm2. Two designs using this method are presented, one that operates for linear polarizations at 0.9 GHz and a smaller polarization-independent design that operates around 1.5 GHz. In the second method, the energy stored in the standing waves of an MPA Fabry-Perot cavity is instead harvested by placing a separate energy harvesting antenna within the cavity. The cavity shapes and enhances the incident electric field, and then the separate energy harvesting antenna is designed to be inserted into the cavity so that its shape and/or radiation pattern matches the electric field lines within the cavity and maximally extracts the stored energy. This method allows for great customization of antenna design parameters, such as operating frequency, polarization dependence, and directionality, by swapping out different metasurface and antenna designs. Using this method, the amount of power harvested by a simple dipole rectenna placed within a cavity is improved by a factor of 18 as compared to what it would harvest by itself at an ambient intensity of 35 nW/cm2. Lastly, the addition of plasmonic structures to DWELL (quantum dot-in-a-well) infrared photodetectors is investigated by computer simulation. DWELL photodetectors have the potential to one day replace standard mercury cadmium telluride detectors by being cheaper alternatives with a higher operating temperature. The inclusion of gold plasmonic structure arrays into DWELL detectors enables excitation of surface plasmon polariton modes that increase the responsivity of the detector to incident infrared radiation. The peak responsivity of a DWELL detector is demonstrated to improve by a factor of 8 for a 1 um thick layer of plasmonic structures and by a factor of 15 for a 2 um thick layer. These works are steps forward in making RF energy harvesting practically useful and for improving infrared photodetector performance.

New possibilit ies exist for the development of novel hardware/software platforms havin g fast data acquisition capability with low power requirements. One application is a high speed Adaptive Design for Information (ADI) system that combines the advantages of feature-based data compression, low power nanometer CMOS technology, and stream computing [1]. We have developed a compressive sensing (CS) algorithm which linearly reduces the data at the analog front end, an approach which uses analog designs and computations instead of smaller feature size transistors for higher speed and lower power. A level-crossing sampling approach replaces Nyquist sampling. With an in-memory design, the new compressive sensing based instrumentation performs digitization only when there is enough variation in the input and when the random selection matrix chooses this input.

Artificial Neural Networks (ANNs) appear increasingly and routinely to gain popularity today, as they are being used in several diverse research fields and many different contexts, which may range from biological simulations and experiments on artificial neuronal models to machine learning models intended for industrial and engineering applications. One example is the recent success of Deep Learning architectures (e.g., Deep Belief Networks [DBN]), which appear in the spotlight of machine learning research, as they are capable of delivering state-of-the-art results in many domains. While the performance of such ANN architectures is greatly affected by their scale, their capacity for scalability both for training and during execution is limited by the increased power consumption and communication overheads, implicitly posing a limiting factor on their real-time performance. The on-going work on the design and construction of spike-based neuromorphic platforms offers an alternative for running large-scale neural networks, such as DBNs, with significantly lower power consumption and lower latencies, but has to overcome the hardware limitations and model specialisations imposed by these type of circuits. SpiNNaker is a novel massively parallel fully programmable and scalable architecture designed to enable real-time spiking neural network (SNN) simulations. These properties render SpiNNaker quite an attractive neuromorphic exploration platform for running large-scale ANNs, however, it is necessary to investigate thoroughly both its power requirements as well as its communication latencies. This research focusses on around two main aspects. First, it aims at characterising the power requirements and communication latencies of the SpiNNaker platform while running large-scale SNN simulations. The results of this investigation lead to the derivation of a power estimation model for the SpiNNaker system, a reduction of the overall power requirements and the characterisation of the intra- and inter-chip spike latencies. Then it focuses on a full characterisation of spiking DBNs, by developing a set of case studies in order to determine the impact of (a) the hardware bit precision; (b) the input noise; (c) weight variation; and (d) combinations of these on the classification performance of spiking DBNs for the problem of handwritten digit recognition. The results demonstrate that spiking DBNs can be realised on limited precision hardware platforms without drastic performance loss, and thus offer an excellent compromise between accuracy and low-power, low-latency execution. These studies intend to provide important guidelines for informing current and future efforts around developing custom large-scale digital and mixed-signal spiking neural network platforms.

The rapid progress of scaling and integration of modern complimentary metal oxide semiconductor (CMOS) technology motivates the replacement of traditional analog signal processing by digital alternatives. Thus, analog-to-digital converters (ADCs), as the interfaces between the analog world and the digital one, are driven to enhance their performance in terms of speed, resolution and power efficiency. However, in the presence of imperfections of device mismatch, thermal noise and reduced voltage headroom, efficient ADC design demands new strategies for design, calibration and optimization. Among various ADC architectures, successive-approximation-register (SAR) ADCs have received renewed interest from the design community due to their low hardware complexity and scaling-friendly property. However, the conventional SAR architecture has many limitations for high-speed, high-resolution applications. Many modified SAR architectures and hybrid SAR architectures have been reported to break the inherent constraints in the conventional SAR architecture. Loop-unrolled (LU) SAR ADCs have been recognized as a promising architecture for high-speed applications. However, mismatched comparator offsets introduce input-level dependent errors to the conversion result, which deteriorates the linearity and limits the resolution and the resolution of most reported SAR ADCs of this kind are limited to 6 bits. Also, for high-resolution SAR ADCs, the comparator noise specification is very stringent, which imposes a limitation on ADC speed and power-efficiency. Lastly, capacitor mismatch is an important limiting factor for SAR ADC linearity, and generally requires dedicated calibration to achieve efficient designs in terms of power and area. In this work, we investigate the impacts of offset mismatch, comparator noise and capacitor mismatch on high-speed SAR ADCs. An analytical model is proposed to estimate the resolution and predict the yield of LU-SAR ADCs with presence of comparator offset mismatch. A background calibration technique is proposed for resolving the comparator mismatch issue. A 150-MS/s 8-bit LU-SAR ADC is fabricated in a 130-nm CMOS technology to validate the concept. The measured result shows that the calibration improves the SNDR from 33.7-dB to 42.9-dB. The ADC consumes 640 μW from a 1.2 V supply with a Figure-of-Merit (FoM) of 37.5-fJ/conv-step. Moreover, the bit-wise impact of comparator noise is studied for LU-SAR ADCs. Lastly, an extended statistical element selection (SES) calibration technique is proposed to calibrate the capacitor mismatch in SAR ADCs. Based on these techniques, a high-resolution, asynchronous SAR architecture employing multiple comparators with different speed and noise specifications to optimize speed and power efficiency. A 12-bit prototype ADC is fabricated in a 1P9M 65nm CMOS technology, and fits into an active area of 500 μm × 200 μm. At 125 MS/s, the ADC achieves a signal-to-noise-and-distortion ratio (SNDR) of 64.4 dB and a spurious-free-dynamic-range (SFDR) of 75.1 dB at the Nyquist input frequency while consuming 1.7 mW from a 1.2 V supply. The resultant figure-of-merit (FoM) is 10.3 fJ/conv-step.

Submitted by Nadir Basilio (nadirsb@uninove.br) on 2016-05-25T14:13:04Z No. of bitstreams: 1 Franciane Barbieri Fiorio.pdf: 1211751 bytes, checksum: 1c9c3d2ae4759d7517b8eb73fab2b12a (MD5) / Made available in DSpace on 2016-05-25T14:13:04Z (GMT). No. of bitstreams: 1 Franciane Barbieri Fiorio.pdf: 1211751 bytes, checksum: 1c9c3d2ae4759d7517b8eb73fab2b12a (MD5) Previous issue date: 2014-12-18 / The optimization of time for the healing of a wound is very important, in view of the consequences it may cause, and this optimization becomes even more relevant in individuals with advanced age, where the repair is slower. The objective of this study was to evaluate the effect of low power laser on healing in an experimental model of skin wounds in aged rats. The skin wound was produced on the back using a "punch" 8mm diameter. 45 rats were males, of which 15 young people (± 30 days) and 30 elderly (± 500 days), divided into three groups, control young, control age and treated which underwent skin wound, and the group old treated received low-level laser treatment (30 mW, power density of 1.07 W / cm2), the area 0,028cm2 beam and wavelength λ660nm, active means of InGaAlP. Analyses were conducted to check the effects of laser on the expression of collagen type I and III, MMP-3, MMP-9, TIMP-2 and VEGF by immunohistochemical staining, IL-6 expression by RT-PCR and CINC-1 expression by ELISA. The results show that the laser decreased IL-6 and IL-8, MMP-3 and MMP-9, increased levels of TIMP-2 and VEGF, and favored collagen I and III deposition at the three time points (3, 7 and 14 days). We can conclude that laser therapy with the parameters used was effective in the treatment of skin wounds in aged animals at different stages of the process of tissue repair by modulating the expression of mediators of tissue repair and collagen deposition. / A otimização do tempo para a cicatrização de uma ferida é de suma importância, tendo em vista as sequelas que ela pode ocasionar e, esta otimização se torna ainda mais relevante no indivíduo com idade avançada, onde o reparo é mais lento. O objetivo deste estudo foi avaliar o efeito do laser de baixa potência na cicatrização em um modelo experimental de feridas cutâneas em ratos idosos. A ferida cutânea foi produzida no dorso do animal utilizando um "punch" de 8mm de diâmetro. Foram utilizados 45 ratos, machos, dos quais 15 jovens (± 30 dias) e 30 idosos (±500 dias), distribuídos em três grupos experimentais, controle jovem, controle idoso e tratado idoso, que foram submetidos à ferida cutânea, e o grupo idoso tratado recebeu tratamento com laser de baixa potência (30 mW, densidade de potência de 1,07 W/cm2), área do feixe de 0,028cm2 e comprimento de onda de λ660nm, meio ativo de InGaAlP. Foram realizadas análises para verificar os efeitos do laser sobre a expressão de colágeno tipo I e III, MMP-3, MMP-9, TIMP-2 e VEGF através de imunoistoquímica, expressão de IL-6 através de RT-PCR e expressão de CINC-1 através de ELISA. Os resultados mostram que o laser diminuiu os níveis de IL-6 e IL-8, de MMP-3 e MMP-9, aumentou os níveis de TIMP-2 e VEGF e favoreceu a deposição de colágeno I e III nos três tempos experimentais (3, 7 e 14 dias). Podemos concluir que a laserterapia com os parâmetros utilizados foi eficaz no tratamento de feridas cutâneas em animais idosos, em diferentes fases do processo de reparação tecidual, modulando a expressão de mediadores do processo de reparo tecidual e deposição de colágeno.