Mutações germinativas no gene TP53 estão associadas com a Síndrome de Li-Fraumeni e sua variante, a Síndrome de Li-Fraumeni-Like, ambas doenças autossômicas dominantes caracterizadas pela predisposição a múltiplos tumores em idade precoce. Recentemente p53 foi descrita como uma proteína com funções antioxidantes, atuando na manutenção da estabilidade genômica. Sendo assim, o objetivo deste trabalho foi investigar parâmetros de estresse oxidativo em sangue periférico de indivíduos portadores da mutação germinativa TP53 p.R337H em comparação com indivíduos não portadores da alteração. Foi verificado que a atividade eritrocitária da enzima GPx, uma importante defesa antioxidante, diferiu significativamente entre portadores e não portadores da mutação, com um aumento da atividade nos primeiros (p=0.048). O conteúdo de grupamentos carbonila e de malondialdeído, indicadores de dano à proteína e a lipídios, respectivamente, também foram significativamente maiores no grupo dos portadores (p=0.04 e p<0.0001). Por fim, indivíduos portadores da mutação apresentaram um aumento no estado antioxidante total, mas uma diminuição no conteúdo de ácido ascórbico em plasma. Nossos resultados apontam para alterações da função antioxidante de p53 em indivíduos portadores da mutação germinativa TP53 p.R337H, independentemente da idade e do diagnóstico prévio de um tumor. Estas alterações podem estar diretamente relacionadas à predisposição ao câncer neste grupo de pacientes. / Germline mutations in the TP53 gene are the underlying genetic defect of Li-Fraumeni Syndrome (LFS) and its variant, Li-Fraumeni-like (LFL) Syndrome, autosomal dominant disorders characterized by predisposition to multiple early-onset cancers. More recently, p53 is emerging as an important player in redox metabolism and important enzymes involved in defenses against oxidative stress have shown to be regulated by p53, including glutathione peroxidase 1 (GPX1) and mitochondrial superoxide dismutase 2 (SOD2). The aim of the present study was to investigate the redox profile parameters in blood of p.R337H mutation carriers and non-carriers individuals. A total of 34 individuals were included in the study and they were divided in two groups: mutation carriers (C) (n=17) and non-carriers (NC) (n=17). Erythrocyte GPx activity, an important enzymatic antioxidant defense, differed significantly between carriers and non carriers, with an increased activity in the latter (p = 0.048). Plasma Carbonyl content, an indicative of protein damage related to ROS overgeneration, was also increased in carriers (p = 0.04). Furthermore, an association between malondialdehyde (MDA, a lipidic peroxidation product) levels and mutation status was found in plasma. Mutation carriers had a four-fold increase in MDA levels (C= 40.20 ± 2.84, NC=160.5 ± 3.64, p < 0.0001) when compared to non carriers. Finally, mutation carriers showed an increased total antioxidant status (TAS), but a decrease in the Vitamin C content in plasma, when compared to non-carriers. Our findings suggest that TP53 p.R337H mutation carriers present an imbalance in oxidative metabolism parameters, which could be directly related to the pathophysiological mechanisms of cancer predisposition in these individuals.

Orientador: Dagmar de Paula Queluz / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Odontologia / Made available in DSpace on 2018-08-05T09:48:38Z (GMT). No. of bitstreams: 1 Nunes_LuizMauricioNogueira_M.pdf: 752283 bytes, checksum: 66bb5395cf7afc984cc85b40a03e0598 (MD5) Previous issue date: 2005 / Resumo: O objetivo deste estudo foi determinar a prevalência de fissuras de lábio e/ou palato no município de Campos dos Goytacazes-RJ, em crianças nascidas entre 01/01/1999 a 31/12/2004, e pesquisar a notificação da ocorrência da malformação na Declaração de Nascido Vivo (DNV) e no Sistema de Informações sobre Nascidos Vivos (SINASC), através de pesquisa no campo 34, destinado à notificação de malformação congênita. Foram considerados a faixa etária, tipo de fissura, gênero e raça da criança, além do estado civil, grau de escolaridade e procedência da mãe do portador na época do parto. Deste modo, foram verificados os prontuários de pacientes inscritos em serviços de referência em tratamento de anomalias craniofaciais, das cidades de Campos dos Goytacazes(RJ), Rio de Janeiro(RJ) e Bauru(SP), com o objetivo de selecionar os nascidos e/ou domiciliados no município de Campos dos Goytacazes, no período de interesse. Após seleção inicial, foi realizada busca no SINASC, definindo o universo do estudo, a saber: nascidos vivos entre 1999 e 2004, cujas mães eram residentes em Campos dos Goytacazes. Neste período, o número de nascidos no município, por residência da mãe, foi de 46.707, dos quais 63 possuíam algum tipo de fissura de lábio e/ou palato, representando uma prevalência de 1,35 casos por 1000 nascidos vivos. A análise dos dados revelou que 55,6% dos pacientes eram do gênero masculino. O tipo de fissura mais encontrado foi o pós-forame incisivo (34,9%), seguido do transforame (31,7%) e do pré-forame incisivo (30,2%). Embora a raça branca tenha representado 61,3% dos indivíduos estudados, o percentual de casos por raça não diferiu estatisticamente em relação à distribuição de nascidos na população. A maior parte das mães era solteira ou separada, possuindo como característica o baixo grau de escolaridade. Em relação à notificação de malformação, diante da análise do preenchimento do campo 34, verificou-se que, tanto a DNV, como, principalmente, o SINASC se mostraram ineficientes no registro das fissuras labiopalatais, em decorrência de falhas no preenchimento das mesmas e, principalmente, pela ausência do preenchimento do código da CID-10 na DNV / Abstract: The purpose of the present study was to determine the prevalence of oral clefts in the city of Campos dos Goytacazes-RJ/BR, in children born from January 01, 1999 to December 31, 2004, and to research the notification of the occurrence of malformation in the Live Births Declaration (LBD) and in the Information System on Live Births (ISLB), through research in the field 34 destined to the notification of congenital malformation. There has been considered the age group, clefts type, gender and the race of the child, as well as the marital status, education degree and the origin of the child¿s mother at the time of the birth. This way, the patients' handbooks enrolled in reference services in treatment of craniofacial anomalies in the cities of Campos dos Goytacazes(RJ), Rio de Janeiro(RJ) and Bauru(SP), were verified with the purpose of selecting the ones whose birth and/or residence was in the city of Campos dos Goytacazes, within the period of interest. After the initial selection, a search in ISLB was accomplished to define the universe of the study, that was: finding the children who were born alive between 1999 and 2004 whose mothers were resident in Campos dos Goytacazes. In this period, using as a reference the residence of the mother, the number of children born in the city was of 46707, of which 63 possessed cleft lip with or without cleft palate, representing a prevalence of 1.35 cases in every 1000 live births. The analysis of the data revealed that 55.6% of the patients were male; the more found cleft type was of isolated cleft palate (34.9%), followed by the cleft lip and palate (31.7%) and the cleft lip (30.2%); the white race represented 61.3% of the cases but the percentage of cases within each race didn¿t differ statistically in relation to the distribution of the births in the population; most of the mothers were single or divorced, having as a characteristic the low education degree. As regarding to the malformation notification, the analysis of the registration field 34 displayed that, the LBD and the ISLB were shown inefficient in the notification of the oral clefts, due to mistakes in the completion of the same ones and, mainly, for the absence of the completion of the International Classification of Diseases (ICD-10) code in LBD / Mestrado / Mestre Profissional em Odontologia em Saúde Coletiva

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The energy source shortage has become a severe issue, and solving the problem with renewable and sustainable energy is the primary trend. Among the new generation energy storage, lithium-sulfur (Li-S) battery stands out for its low cost, high theoretical capacity (1,675 mAh g-1), and environmentally friendly properties. Intensive researches have been focusing on this system and significant improvement has been achieved. However, several problems still need to be resolved for its practical application, especially for the “shuttle effect” issue coming from the dissolved intermediate polysulfides, which could cause rapid capacity decay and low Coulombic efficiency (CE). Several methods are proposed to eliminate this issue, including using interlayers, modifying separators, and protecting the lithium anode. A carbon interlayer is first introduced to compare the function of the graphene and carbon nanotubes (CNTs), while the CNTs performs better with its higher conductivity and 3D network structure. The following study is conducted based on this finding. A more efficient method is to modify the separator with functional materials. 1) The dissolved polysulfide (Sn2-) could be repelled by electrostatic forces. With the Poly (styrene sulfonate) (PSS), the separator could function as an anion barrier to the intermediate polysulfides. 2D ultra-thin zinc benzimidazolate coordination polymer has the OH- functional groups and works with the same mechanism. 2) A novel covalent organic framework (COF) has a relatively small pore size, which can block the polysulfide and restrain them at the cathode side. 3) Metal-organic framework (MOF) materials have the adjustable pore size and structure, which can absorb and trap polysulfides within their cavities. Moreover, the dense stacking of the MOF particles creates a physical blocking for the polysulfides, which efficiently suppresses the diffusion process. Protection of the lithium surface directly with an artificial layer or a solid electrolyte interphase (SEI) can inhibit the polysulfide deposition and suppress the lithium dendrite. A polyvinylidene difluoride (PVDF) membrane is used as an artificial film on lithium anode, which could greatly enhance the battery cyclability and CE. Future work will be conducted based on this concept, especially building an artificial SEI.

Lithium-sulfur (Li-S) batteries are faced with practical drawbacks of poor cycle life and low charge efficiency which hinder their advancements. Those drawbacks are primarily caused by the intrinsic issues of the cathodes (sulfur) and the anodes (Li metal). In attempt to resolve the issues found on the cathodes, this work discusses the method to prepare a binder-free three-dimensional carbon nanotubes-sulfur (3D CNTs-S) composite cathode by a facile and a scalable approach. Here, the 3D structure of CNTs serves as a conducting network to accommodate high loading amounts of active sulfur material. The efficient electron pathway and the short Li ions (Li+) diffusion length provided by the 3D CNTs offset the insulating properties of sulfur. As a result, high areal and specific capacities of 8.8 mAh cm−2 and 1068 mAh g−1, respectively, with the sulfur loading of 8.33 mg cm−2 are demonstrated; furthermore, the cells operated at a current density of 1.4 mA cm−2 (0.1 C) for up to 150 cycles. To address the issues existing on the anode part of Li-S batteries, this work also covers the novel approach to protect a Li metal anode with a thin layer of two-dimensional molybdenum disulfide (MoS2). With the protective layer of MoS2 preventing the growth of Li dendrites, stable Li electrodeposition is realized at the current density of 10 mA cm−2; also, the MoS2 protected anode demonstrates over 300% longer cycle life than the unprotected counterpart. Moreover, the MoS2 layer prevents polysulfides from corroding the anode while facilitating a reversible utilization of active materials without decomposing the electrolyte. Therefore, the MoS2 protected anode enables a stable cycle life of over 500 cycles at 0.5 C with the high sulfur loading amount of ~7 mg cm−2 (~67 wt% S content in cathode) under the low electrolyte/sulfur (E/S) ratio of 6 μL mg−1. This translates to the specific energy and power densities of ~550 Wh kg-1 and ~300 W kg−1, respectively. Additionally, such values far exceed the electrochemical performance of the current Li-ion batteries. Therefore, the synergetic effect of utilizing the 3D CNT-S cathode and the MoS2 protected Li anode will allow the Li-S batteries to become applicable for the transportation and the large-scale energy grid applications.

Lithium-ion batteries are of great importance for today's society. The state-of-the-art batteries that are used today use a fluorinated electrolyte that contains the salt LiPF6 and acts as both a safety hazard and an environmental issue due to its ability to form the toxic gas hydrogen fluoride (HF). This project aims to find a fluorine-free electrolyte that can be used in silicon-based lithium-ion batteries to make them more environmentally friendly without detriment to the electrochemical performance. To do so, an additive that may form a solid electrolyte interphase (SEI) stable enough to allow a fluorine-free electrolyte to replace the ones used today is sought for. The salt of interest is lithium  bis(oxalato)borate (LiBOB). Based on previous research electrolytes using LiBOB in either the solvent γ-Butyrolactone (GBL) or a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) are examined. The additives used are vinylene carbonate (VC) and 1,3,2-dioxathiolane 2,2-dioxide (DTD). Techniques used are cyclic voltammetry, linear sweep voltammetry, galvanostatic charge and discharge, X-ray photoelectron spectroscopy and scanning electron microscopy.  The cells using GBL as solvent have cycled very poorly during this project while LiBOB in EC:EMC + VC shows the most promising results, with highest capacity retention and less amount of degraded LiBOB during the first charge. It is also to be noted that both EC:EMC based electrolytes provide the formation of a passivating solid electrolyte interface (SEI) and are of interest for further investigation based on the results obtained during this project.

Lithium-Ionen-Batterien besitzen ein ausgezeichnetes Potential für die Energiespeicherung. Das derzeit dominierende Anodenmaterial in Lithium-Ionen-Batterien mit einer Energiespeicherkapazität von 339 mAh/g ist Graphit. Als Alternative hierfür bieten sich Lithiumsilicide und Lithiumstannide an. Diese Materialien zeichnen sich durch eine viel größere Speicherkapazität und geringere Selbstentladungspotentiale aus. Für die kommerzielle Anwendung dieser beiden Systeme in Lithium-Ionen-Batterien werden grundlegende und verlässliche thermodynamische Daten benötigt. Derzeit ist die Existenz von sieben Lithiumsiliciden sicher nachgewiesen. Dazu zählen die sechs stabilen Phasen Li17Si4, Li16.42Si4, Li13Si4, Li7Si3, Li12Si7, die Hochdruckphase LiSi und die metastabile Phase Li15Si4. Für die ersten fünf genannten Phasen wurden in der ersten Förderperiode des Schwerpunktprogrammes 1473 Wärmekapazitäten und Standardentropien bestimmt. Bei den Lithiumstanniden sind derzeit sieben Phasen gesichert belegt. Allerdings existiert für keine Phase der Lithiumstannide ein verlässlicher thermodynamischer Basisdatensatz. Aus diesem Grund wurden für die beiden zuletzt genannten Lithiumsilicide (Li15Si4 und LiSi), sowie für die Lithiumstannide Li17Sn4, Li7Sn2, Li13Sn5 und Li7Sn3 die fehlenden thermodynamischen Daten experimentell bestimmt. Die hergestellten Phasen wurden zunächst mittels Röntgenbeugung, thermischer und chemischer Analyse charakterisiert. Ein Schwerpunkt dieser Arbeit lag auf der experimentellen Bestimmung der Wärmekapazitäten in einem Temperaturbereich von 2 K bis zur jeweiligen Zersetzungstemperatur der untersuchten Verbindungen. Hierfür wurden zwei unterschiedliche Kalorimeter verwendet: ein Physical Property Measurement System (Quantum Design) von 2 K bis 300 K und eine DSC 111 (Setaram), beginnend ab 300 K. Die experimentellen Daten konnten mit Messunsicherheiten von 1 % bis 2 % über 20 K und bis zu 20 % unterhalb von 20 K angegeben werden. Die Messungen bei niedrigen Temperaturen erlauben zudem die Berechnung der Standardentropien, sowie die Bestimmung von elektronischen Beiträgen und Gitterschwingungsbeiträgen zur Wärmekapazität. Weiterhin ist Fokus dieser Arbeit die Bestimmung der Standardbildungsenthalpien der Lithiumsilicide und Lithiumstannide auf Basis von Wasserstoffsorptionsmessungen mittels einer Sieverts-Apparatur. Hierfür wurden erstmals Messungen an den Lithiumsiliciden ausgehend von Li17Si4, LiH:Si (Li:Si = 17:4), Li16.42Si4 und LiSi durchgeführt. Für die Lithiumstannide dienten als Ausgangsmaterial Li17Sn4, LiH:Sn (Li:Sn =17:4), sowie Li7Sn2 und LiH:Sn (Li:Sn = 7:2). Die Anwendung des van´t-Hoff-Plots resultierte in Messunsicherheiten von mindestens 10 %. Aus diesem Grund wurde eine alternative Auswertemethode gewählt, bei der die ermittelten Wärmekapazitäten und Standardentropien mit den Gleichgewichtsdrücken aus den Wasserstoffsorptionsmessungen miteinander verknüpft werden. Auf diese Weise konnten Standardbildungsenthalpien für die untersuchten Phasen mit Fehlern kleiner 1 % ermittelt werden. Aus den Ergebnissen dieser Arbeit resultierte ein vollständiger, gesicherter thermodynamischer Datensatz für das System Li-Si. Das berechnete Li-Si-Phasendiagramm ist im sehr guten Einklang mit experimentellen literaturbekannten Daten. Für die Lithiumstannide erfolgte eine Validierung der ermittelten thermodynamischen Werte. Die in dieser Arbeit erzielten Ergebnisse liefern einen wesentlichen Beitrag zur Verbesserung der Datenbasis für thermodynamische Berechnungen und für das Verständnis von Phasensequenzen und Gleichgewichten beim Einsatz von Lithiumsiliciden bzw. Lithiumstanniden als Anodenmaterialien in Lithium-Ionen-Batterien.

Stricter regulations concerning emissions from road traffic and increasing fuel prices has lead to an interest in hybrid electric vehicles (HEVs). Today even manufacturers of heavy duty vehicles are introducing hybrid alternatives. Batteries are expensive and a complex part in HEVs, and ways of determining a battery’s capacity is a current research topic. When a battery is used it ages, i.e. the capacity decreases and the impedance rises. Since battery cost is high, it is important to be able to determine battery ageing properly. The focus of this master thesis has been on impedance measurement methods for Li-ion batteries. The work has been carried out in cooperation with Scania CV AB. When a battery is aged, the impedance increases. Monitoring ageing mechanisms could enable increased lifetime of the batteries through optimized usage in for example heavy duty hybrid vehicles. In this work, Hybrid Pulse Power Characterization (HPPC) has been compared with Electrochemical Impedance Spectroscopy (EIS). A major difference between these methods is that HPPC uses pulses of high direct current, whereas a small alternating current perturbation is used in EIS. EIS give information about different mechanisms influencing the battery impedance, e.g. internal resistance and charge transfer resistance, but requires expensive and complex laboratory equipment. HPPC gives less detailed information about the impedance, but is more similar to field applications for a vehicle. A literature survey showed that much research is conducted on in-situ impedance measurements of batteries. One example is the long-term demonstration of an Impedance Measurement Box (IMB), which is currently carried out at Idaho National Laboratory. The method uses a sum-of-sines signal consisting of octave harmonics for a fast impedance measurement with good precision. The results showed a good correlation with laboratory EIS measurements. The experimental part of this project suggest that a linear correlation  exists between the discharge resistance from HPPC measurements and the sum of internal resistance and charge transfer resistance from EIS measurements. The linear fitting did not have very good R-squared value but a residual analysis showed that the residuals were randomly scattered around zero, indicating that a linear fitting is suitable. However, the precision of the results is too poor for the correlation to be useful in a real HEV application. Additional work to improve the linear fitting is recommended. Furthermore, it was showed that AC-components have to be used as a measurement signal in order to measure the complex impedance of a battery. A paired t-test was conducted in order to study if noise could be used as that signal for a battery under load. The impedance at 100 Hz was calculated, which corresponds to the second harmonic of the power grid. The difference between this impedance and the impedance measured at 100 Hz with EIS was statistically tested. For shorter times pans (in this case 20 milliseconds) after applying the DC pulse, using noise cannot be ruled out for measuring a battery’s impedance under load. But for longer time spans after applying the DC pulse (in this case 1.3 seconds), there was a significant difference between the two methods. Concentration gradients caused by mass transfer limitations could be causing this effect.

Lithium-ion batteries are a rapidly growing power source for mobile applications such as electric vehicles. A battery model algorithm that estimates and predicts important battery parameters like terminal voltage and state-of-charge is necessary to maintain safe operation during discharge. Hence, a semi-empirical electrochemical-based model was proposed and implemented in MATLAB for discharge simulation and parameter estimation. This thesis also investigated several essential factors like internal resistance and operational temperature, which impact a battery cell during discharge.  The proposed model was a modification of Shepherd’s model that included both kinetic and diffusive components representing the total battery overpotential and a temperature- dependent coefficient. These were used for the determination of the battery’s internal resistance and the temperature effect. The model accounts for all dynamic characteristics of a Li-ion battery, including non-linear open-circuit voltage, internal resistance, discharge current, and capacity.  Model validation was performed using test profiles, including data provided by the battery manufacturer and experimental data for a test profile provided by Saab Dynamics. The simulated profiles were found to match the measured profiles. Although, some deviations occurred, especially during rapid changes in C-rates. The proposed model in this work shows that the simulation results compared to the experimental data had deviations within ~2% for the constant current discharge test, and the dynamic model managed to cover the experimental discharge voltage during different temperatures with good consistency and minor errors. Therefore, the proposed model can compete with other battery modeling methods.