<div>Partition Density Functional Theory (P-DFT) is a formally exact method to find the ground-state energy and density of molecules via self-consistent calculations on isolated fragments. It is being used to improve the accuracy of Kohn-Sham DFT (KS-DFT) calculations and to lower their computational cost. Here, the method has been extended to be applicable to semi-infinite and periodic systems. This extension involves the development of new algorithms to calculate the exact partition potential, a central quantity of P-DFT. A novel feature of these algorithms is that they are applicable to systems of constant chemical potential, and not only to systems of constant electron number. We illustrate our method on one-dimensional model systems designed to mimic metal-atom interfaces and atomic chains. From extensive numerical tests on these model systems, we infer that: 1.) The usual derivative discontinuities of open-system KS-DFT are reduced (but do not disappear completely) when an atom is at a nite distance from a metallic reservoir; 2.) In situations where we do not have chemical potential equalization between fragments of a system, a new constraint for P-DFT emerges which relates the fragment chemical potentials and the combined system chemical potential; 3.) P-DFT is an ideal method for studying charge transfer and fragment interactions due to the correct ensemble treatment of fractional electron charges; 4.) Key features of the partition potential at the metalatom interface are correlated to well-known features of the underlying KS potential; and 5.) When there is chemical potential equalization between an atom and a metal surface it is interacting with, there is strong charge transfer between the metal and atom. In these cases of charge transfer the density response to an innitesimal change in the chemical potential is located almost exclusively around the atom. On the other hand, when the fragment chemical potentials do not equalize, the density response only aects the surface Friedel oscillations in the metal.</div>

Radiotherapy planning involves the calculation of dose deposition throughout the patient, based upon quantitative electron density images from computed tomography (CT) scans taken before treatment. Cone beam CT (CBCT), consisting of a point source and flat panel detector, is often built onto radiotherapy delivery machines and used during a treatment session to ensure alignment of the patient to the plan. If the plan could be recalculated throughout the course of treatment, then margins of uncertainty and toxicity to healthy tissues could be reduced. CBCT reconstructions are normally too poor to be used as the basis of planning however, due to their insufficient sampling, beam hardening and high level of scatter. In this work, we investigate reconstruction techniques to enable dose calculation from CBCT. Firstly, we develop an iterative method for directly inferring electron density from the raw X-ray measurements, which is robust to both low doses and polyenergetic artefacts from hard bone and metallic implants. Secondly, we supplement this with a fast integrated scatter model, also able to take into account the polyenergetic nature of the diagnostic X-ray source. Finally, we demonstrate the ability to provide accurate dose calculation using our methodology from numerical and physical experiments. Not only does this unlock the capability to perform CBCT radiotherapy planning, offering more targeted and less toxic treatment, but the developed techniques are also applicable and beneficial for many other CT applications.

Implementation of optical refrigeration (OR) in quantum dot (QD) materials was achieved for the first time. An OR experiment was designed and carried out in our lab and a maximum temperature drop around 0.68 K was observed in the zinc-blende crystalline CdSe/CdS (core/shell structure) QD samples under laser excitation. The cooling effect was achieved by utilizing the energy up-conversion photoluminescence (PL) of CdSe/CdS QDs with sub-band excitation. While the cooling efficiency of the system was estimated and optimized by a semi-empirical model built during this research. <div><br></div><div>This work has proved the capability of QD materials to be used as a cooling substance for OR, which significantly expanded the possible candidates for OR. The technique could have many applications, such as harvesting cooling effect from sun light with the help of metamaterials, which can produce quasi-monochromatic light. It may also be used to cool QD in optical traps, which leading may help to develop new ultra-sensitive sensors and application for quantum information science.</div>

Orientador: Dimas Roberto Vollet / Banca: José Ramon Beltran Abrego / Banca: Dario Antonio Donatti / Resumo: O objetivo deste trabalho foi estudar as características estruturais em géis de sílica preparados a partir da hidrólise ácida do tetraetilortosilicato (TEOS) com adições do surfactante aniônico dodecil sulfato de sódio (SDS) e de n-heptano como fase oleosa. Os géis são estudados em estágios que vão do estado saturado (gel úmido) até o estado seco do gel (aerogel) resultante da secagem à pressão ambiente. As caracterizações estruturais das amostras são realizadas através das técnicas de Termogravimetria (TG), densidade aparente, análise de distribuição de tamanho de poros e área superficial por Adsorção de Nitrogênio, e espalhamento de raios-X a baixo ângulo (SAXS). A razão molar água/TEOS e o volume da mistura dos reagentes foram mantidos constantes no processo de hidrólise para todas as adições de n-heptano. Foram obtidos dois grupos de géis úmidos, num primeiro grupo a fase líquida dos géis úmidos foi trocada por água para remoção da microemulsão (amostras Ta) e no outro além da troca por água foi feito troca por uma solução de trimetilclorosilano (TMCS) em álcool isopropílico, para modificação da superfície da sílica (sililação), e finalmente por álcool isopropílico puro (amostras Tm). A estrutura dos géis úmidos pode ser descrita como a de uma estrutura fractal de massa com tamanho característico de cerca de 10 nm e dimensão fractal D em torno de 2.2, composto de partículas primárias de sílica de tamanho característico a1, estimadas como sendo da ordem de 0.7 nm para os géis úmidos Ta e menor do que 0.4 nm para os géis úmidos Tm. Aerogéis foram obtidos por secagem à pressão ambiente a partir dos géis úmidos Tm (aerogéis IPA) e a partir dos géis úmidos Tm com mais uma troca de fase líquida, desta vez por acetona (aerogéis ACE). O processo de secagem estreita o intervalo de comprimentos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aims to study the structural characteristics of silica gels prepared from hydrolysis of tetraethylortosilicate (TEOS) with additions of the anionic surfactant sodium dodecyl sulfate (SDS) and n-heptane as an oily phase. The gels are studied in stages from the saturated state (wet gels) to dried gels (aerogels), resulting from the ambient pressure drying. The samples are characterized by Termogravimetry (TG), apparent density, surface area and porous size distribution by nitrogen adsorption, and small-angle X-ray scattering (SAXS). The water/TEOS molar ratio and the reactant mixture volume were kept constant during the hydrolysis process for all additions of n-heptane. The liquid phase of the wet gels was changed by water (Ta samples), in order to washing for removing the micro-emulsions, followed by changing water by a trimethylchrorosilane (TMCS) solution, in order to modify the silica surface (sililation), and finally changing the TMCS solution by pure isopropyl alcohol (Tm samples). The structure of the wet gels can be described by a mass fractal structure with characteristic size of about 10 nm and fractal dimension of about 2.2, built up by primary silica particles of characteristic size a1, which was found to be about 0.7 nm for the wet gels Ta and smaller than 0.4 nm for the wet gels Tm. Aerogels were obtained by ambient pressure drying from the wet gels Tm (IPA aerogels) and from the wet gels Tm but with once more change of liquid phase, now by acetone (ACE aerogels). The drying process shortens the length scale range of the mass fractal structure of the original wet gels (diminishes and increases a1), without, however, modify substantially the mass fractal dimension D. The mass fractal structure of the original wet gels seems to evolve in the aerogels to a mass and surface fractal structure, when it is observed at high resolution. The values of the specific surface... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:25:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-09-23Bitstream added on 2014-06-13T20:53:30Z : No. of bitstreams: 1 viceli_mr_me_rcla.pdf: 1171030 bytes, checksum: e09b1414b017e8dddec96fe741c253b7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste trabalho foi estudar as características estruturais em géis de sílica preparados a partir da hidrólise ácida do tetraetilortosilicato (TEOS) com adições do surfactante aniônico dodecil sulfato de sódio (SDS) e de n-heptano como fase oleosa. Os géis são estudados em estágios que vão do estado saturado (gel úmido) até o estado seco do gel (aerogel) resultante da secagem à pressão ambiente. As caracterizações estruturais das amostras são realizadas através das técnicas de Termogravimetria (TG), densidade aparente, análise de distribuição de tamanho de poros e área superficial por Adsorção de Nitrogênio, e espalhamento de raios-X a baixo ângulo (SAXS). A razão molar água/TEOS e o volume da mistura dos reagentes foram mantidos constantes no processo de hidrólise para todas as adições de n-heptano. Foram obtidos dois grupos de géis úmidos, num primeiro grupo a fase líquida dos géis úmidos foi trocada por água para remoção da microemulsão (amostras Ta) e no outro além da troca por água foi feito troca por uma solução de trimetilclorosilano (TMCS) em álcool isopropílico, para modificação da superfície da sílica (sililação), e finalmente por álcool isopropílico puro (amostras Tm). A estrutura dos géis úmidos pode ser descrita como a de uma estrutura fractal de massa com tamanho característico de cerca de 10 nm e dimensão fractal D em torno de 2.2, composto de partículas primárias de sílica de tamanho característico a1, estimadas como sendo da ordem de 0.7 nm para os géis úmidos Ta e menor do que 0.4 nm para os géis úmidos Tm. Aerogéis foram obtidos por secagem à pressão ambiente a partir dos géis úmidos Tm (aerogéis IPA) e a partir dos géis úmidos Tm com mais uma troca de fase líquida, desta vez por acetona (aerogéis ACE). O processo de secagem estreita o intervalo de comprimentos... / This work aims to study the structural characteristics of silica gels prepared from hydrolysis of tetraethylortosilicate (TEOS) with additions of the anionic surfactant sodium dodecyl sulfate (SDS) and n-heptane as an oily phase. The gels are studied in stages from the saturated state (wet gels) to dried gels (aerogels), resulting from the ambient pressure drying. The samples are characterized by Termogravimetry (TG), apparent density, surface area and porous size distribution by nitrogen adsorption, and small-angle X-ray scattering (SAXS). The water/TEOS molar ratio and the reactant mixture volume were kept constant during the hydrolysis process for all additions of n-heptane. The liquid phase of the wet gels was changed by water (Ta samples), in order to washing for removing the micro-emulsions, followed by changing water by a trimethylchrorosilane (TMCS) solution, in order to modify the silica surface (sililation), and finally changing the TMCS solution by pure isopropyl alcohol (Tm samples). The structure of the wet gels can be described by a mass fractal structure with characteristic size of about 10 nm and fractal dimension of about 2.2, built up by primary silica particles of characteristic size a1, which was found to be about 0.7 nm for the wet gels Ta and smaller than 0.4 nm for the wet gels Tm. Aerogels were obtained by ambient pressure drying from the wet gels Tm (IPA aerogels) and from the wet gels Tm but with once more change of liquid phase, now by acetone (ACE aerogels). The drying process shortens the length scale range of the mass fractal structure of the original wet gels (diminishes and increases a1), without, however, modify substantially the mass fractal dimension D. The mass fractal structure of the original wet gels seems to evolve in the aerogels to a mass and surface fractal structure, when it is observed at high resolution. The values of the specific surface... (Complete abstract click electronic access below)

Orientador: José Roberto Campanha / Banca: Edson Denis Leonel / Banca: Camilo Rodrigues Neto / Resumo: O objetivo do nosso trabalho é a aplicação de um modelo estendido da distribuição do tipo Tsallis e sua aplicação em ações da Bolsa de Valores de São Paulo. Em nosso caso procuramos ações de diferentes setores da nossa economia. Escolhemos então uma ação do setor bancário (Banco do Brasil), do setor de mineração (Vale) e por último uma ação do setor de papel e celulose (Votorantim Celulose e Papel). Na distribuição do tipo Tsallis o índice entrópico q possui um valor constante, em nosso modelo, propomos que ele seja um função exponencialmente decrescente da variável que descreve o tamanho do sistema sendo considerado. Em nosso caso (ações), a variável em consideração é o retorno clássico. Observamos que na maioria dos casos tratados, não houve necessidade do modelo estendido, mas em um caso foi necessário o uso deste para encontrarmos o melhor ajuste para a distribuição de probabilidade. / Abstract: The objective of our work is the application of an extended version of Tsallistype distribution and its application in the shares of stock exchange of São Paulo. In our case seek shares of different sectors of our economy. Then choose an action of the banking sector (Banco do Brasil), of the mining sector (Vale) and finally an action in the sector of paper and cellulose (Votorantim Celulose e Papel). Tsallis type distribution of the entropy index q has a constant value in our model, we propose that it is an exponentially decreasing function of the variable that describes the size of the system being considered. In our case (stock), the variable account is the classic back. We observed that in most cases, there was no need for the extended model, but in one case it was necessary to use this to find the best fit for the distribution of probability. / Mestre

Orientador: Dimas Roberto Vollet / Banca: Dario Antonio Donatti / Banca: Dermeval José Mazzini Sartori / Resumo: O objetivo deste trabalho foi estudar as características estruturais em géis úmidos de sílica preparados a partir da hidrólise ácida de Tetraetilortosilicato (TEOS) com adições do surfactante aniônico Dodecil Sulfato de Sódio (SDS). O surfactante foi removido após a gelificação. Os géis úmidos exibem uma estrutura fractal de massa com dimensão fractal de massa D (típicamente em torno de 2,25) numa escala de comprimentos que se estende desde o tamanho característico ξ (geralmente em torno de 10 nm) do domínio do fractal de massa até um tamanho característico a0 (típicamente entre 0,3 - 0,4 nm) da partícula primária que constituí o domínio fractal. ξ aumenta enquanto que D e a0 diminuem ligeiramente com o aumento da quantidade de SDS. Aerogéis SCD com superfície específica típica de 1000 m2 /g e massa específica aparente de 0,20 g/cm3 foram obtidos por secagem supercrítica (SCD) dos géis úmidos depois da lavagem com etanol. O volume de poros e o tamanho médio de poros aumentaram com o aumento da quantidade de SDS. Os aerogéis SCD preservaram a maior parte das características do fractal de massa dos géis úmidos originais em larga escala de comprimento e exibiram num nível de resolução em torno de 0,7 nm uma mudança („crossover‟) para uma estrutura de fractal de massa e superfície, com dimensão aparente de fractal de massa Dm ~ 2,4 e dimensão de fractal de superfície Ds ~ 2,6, conforme concluído a partir dos dados de espalhamento de raios-X à baixo angulo (SAXS) e adsorção de Nitrogênio. Aerogéis hidrofóbicos secos a pressão ambiente (APD) apresentaram superfície específica típica de 800 m2 /g e massa específica aparente de 0,20 g/cm3 e foram obtidos após sililação dos precursores géis úmidos com uma mistura de Hexametildisiloxano (HMDSO) e Trimetilclorosilano (TMCS). O volume de poros e o tamanho médio (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work aims to study the structural characteristics of silica wet gels prepared from hydrolysis of Tetraethoxysilane (TEOS) with additions of the anionic surfactant Sodium Dodecyl-Sulfate (SDS). The surfactant was removed after gelation. Wet gels exhibited massfractal structure with mass-fractal dimension D (typically around 2.25) in a length scale extending from a characteristic size ξ (typically about 10 nm) of the mass-fractal domains to a characteristic size a0 (typically between 0.3 - 0.4 nm) of the primary particles building up the fractal domains. ξ increased while D and a0 diminished slightly as the SDS quantity increased. Aerogels with typical specific surface of 1000 m 2 /g and density of 0.20 g/cm3 were obtained by supercritical drying (SCD) of the wet gels after washing with ethanol and n-hexane. The pore volume and the mean pore size increased with the increase of the SDS quantity. The aerogels presented most of the mass-fractal characteristics of the original wet gels at large length scales and exhibited at a higher resolution level at about 0.7 nm a crossover to a masssurface fractal structure, with apparent mass-fractal dimension Dm ~ 2.4 and surface-fractal dimension Ds ~ 2.6, as inferred from small-angle X-ray scattering (SAXS) and Nitrogen adsorption data. Hydrophobic ambient pressure drying (APD) aerogels with typical specific surface of 800 m2 /g and bulk density of 0.20 g/cm3 were obtained after silylation of the precursor wet gels with a mixture of Hexamethyldisiloxane (HMDSO) and Trimethylchlorosilane (TMCS). The pore volume and the mean pore size of the APD aerogels increased with increasing the SDS quantity. APD aerogels presented most of the mass-fractal characteristics of the precursor wet gels at large length scales. The radius of gyration of the clusters of the APD aerogels (typically 17 nm) increased (Complete abstract click electronic access below) / Mestre

Em arqueometria e nas ciências aplicadas, metodologias físicas e químicas são de grande utilidade para estudar diferentes materiais e objetos do patrimônio cultural como pinturas de cavalete, murais, cerâmicas, metais, etc. No caso particular de pinturas, tais análises podem auxiliar na compreensão do processo criativo, dos materiais utilizados pelo artista e do estado de conservação desta obra. No contexto deste último item, podem ser caracterizados sinais de degradação, como a alteração de cores. Dentro do objetivo de compreender a degradação de alguns pigmentos por exposição luminosa, estudaram-se os pigmentos amarelo de cádmio (CdS), amarelo de cromo (PbCrO4), azul de cobalto (CoAl2O4) e cerúleo (Co2SnO4), sendo estes dois últimos também misturados ao branco de zinco (ZnO). Tais estudos foram realizados através de três ensaios com amostras padrões preparadas com estes pigmentos: fotodegradação induzida na linha TGM (Toroidal Grating Monochromator) do Laboratório Nacional de Luz Síncrotron; exposição à luz ultravioleta no simulador solar SOL-UV; e exposição às radiações ultravioleta, visível e infravermelha em uma câmara projetada neste mestrado. Os resultados apontaram para indicativos de alteração em todas as amostras, em especial mudanças no espectro de reflectância na região do visível. Por fim, analisaram-se amostras de tintas obtidas de obras do pintor Candido Portinari que possuíam indícios de alteração cromática. A partir destes fragmentos, construíram-se modelos estratigráficos dos materiais utilizados pelo artista nestas pinturas. / In archeometry and applied sciences, physical and chemical methodologies are very useful for studying different materials and objects of cultural heritage such as easel paintings, murals, ceramics, metals, etc. In the particular case of paintings, such analyses can help in understanding the creative process, the materials used by the artist and the conservation status of this work. In the context of this latter item, signs of degradation, such as color change, can be characterized. In order to understand the degradation of some pigments by light exposure, the cadmium yellow (CdS), chrome yellow (PbCrO4), cobalt blue (CoAl2O4) and cerulean blue (Co2SnO4) pigments were studied, the latter two being also mixed with zinc white pigment (ZnO). Such studies were carried out through three experiments prepared with these pigments: photodegradation induced in the TGM (Toroidal Grating Monochromator) line of the National Laboratory of Synchrotron Light; exposure to ultraviolet light in the SOL-UV solar simulator; and exposure to ultraviolet, visible and infrared radiation in a chamber designed in this master\'s degree. The results pointed out changes in all samples, especially in their reflectance spectrum in the visible region. Finally, samples obtained from works by the painter Candido Portinari that had signs of chromatic alteration were analyzed. Based on these fragments, stratigraphic models of the materials used by the artist in these paintings could be constructed.

<div>Single phase immiscible fluid flow in porous media is often described by Darcy’s law. However, in two-phase or multi-phase conditions, the properties of porous medium rely on the saturation of each phase. One of the constitutive equations, the relationship between capillary pressure and saturation, exhibits hysteresis property. To accurately describe two-phase immiscible fluid in porous media, some researchers used interfacial area per volume (IAV) as an additional variable. Previous experiments were done by other experimenters to support the uniqueness of IAV in capillary pressure – saturation hysteresis relationship by externally changing the capillary pressure. </div><div>A technique called Electro-Wetting On Dielectric (EWOD) was developed for sealed micro-models to examine the saturation-pressure relationship by internally manipulating the saturation which in turns affects IAV. Single-plate EWOD samples were used to select material properties and experimental parameters. These experiments found that Poly-Di-Methyl-Siloxane (PDMS) is a good dielectric material that enabled changes in the contact angle between a droplet and PDMS from ~120° (non-wetting) to ~50° (wetting). Double-plate EWOD was used to demonstrate that discrete electrodes (with PDMS as dieletric on both plates) enabled the transportation and merging of droplet(s).</div><div>A novel method was developed to incorporate EWOD into a wedge-shaped PDMS micro-model. Imbibition and drainage scans of the capillary pressure – saturation relationship (Pc-S) were performed in the channel with and without voltage. The drainage curves differed significantly between the two conditions, while the imbibition curves were similar with and without voltage. The total energy for Pc-S decreased by 70 nJ with the application of EWOD with most of difference arising from a 20 Pa decrease in pressure for the same saturation condition during drainage.</div><div>Studies were also performed to examine the amount of energy associated with depiing of fluid interfaces. A 5-step wedge-shaped micro-model with EWOD was fabricated to increase the probability of pinning during an experiment. The amount of energy released as a fluid depinned was observed to be a function of capillary pressure. More energy was released at the 1st step for higher the pressures than lower pressures. The energy released from depinning at the first step in the channel ranged from 30 – 100 nJ for pressures from 70 to 100 Pa. The occurrence and magnitude of additional depinnings along the step-shaped channel also depended on the pressure. Each successive depining released less energy.</div><div>Finally, experiments were performed to examine the range of EWOD in a sealed micro-model with discrete electrodes. When voltage was not applied directly on the fluid-fluid interface but on the solution, the voltage could still actuate the interface causing it to move and advance farther into a channel. The ability of the application of EWOD to drive fluid-fluid interfaces decreases with active electrode distance from the interface.</div>

Proteomics is the large scale study of proteins in biological systems such as those found in human cells. The understanding of proteomes, i.e. the complete set of proteins expressed by an organism, has especially useful applications in the medical field such as genetic research and drug discovery. Cells that undergo biochemical processes affect the state of the contained proteins, therefore producing an abundance of physical variations and permutations of single proteins. The main goal of proteomic studies is to identify the proteins related to such processes in order to study their purpose and function. Successful reduction of the so-called "search space" in which proteins are identified, is a large determining factor in the resulting number of correct protein identifications. Fractionation processes attempt to reduce this search space through electrophoretic experiments such as IEF in order to identify individual protein properties such as the isoelectric point. Protein sample preparation relies heavily on isoelectric point values, denoted $p$I, and hence accurate theoretical prediction of these values would provide a benchmark to aid in analytical processes such as LC-MS. This dissertation explores the efficacy of using simple feature encoding to improve upon conventional theoretical $p$I predictions, based on the Henderson-Hasselbalch equation, in order to more accurately reflect experimental values. Simple feature encoding was used for two different optimisation techniques. Encoding chargeable amino acid residues in peptide sequences into various $k$-mer combinations produced a considerable improvement in predicted $p$I values compared to prediction solely based on reference $p$K$_a$ values. The approaches taken in this project highlighted, arguably at a fundamental level, the useful nature of peptide feature encoding to improve theoretical $p$I predictions. However, future research endeavours should consider extending the models discussed using more developed and complex modelling techniques for peptide sequences and more importantly, $p$K$_a$ constants. / Proteomik är en gren av biologin som omfattar den storskaliga forskning av proteiner i biologiska system som till exempel de som befinner sig i mänskliga celler. Proteomet utgörs av samtliga former av proteinmolekyler som uttrycks av genomet av en organism. Förståelsen av proteomet har brukbar användning inom medicinsk forskning såsom genetik- och läkemedelsforskning. Celler som genomgår biokemiska processer påverkar molekylernas tillstånd och struktur som i sin följd producerar en mångfald av permutationer och variationer av enskilda proteiner. Målet med proteomiska studier är att identifiera olika proteiner och relatera dessa till biologiska processer för att förstå deras funktion och syfte. Minskning av den så kallade sökrymden för proteiner avgör till stor del antalet korrekta identiferingar som tas fram. Sökrymden kan minskas med hjälp av fraktioneringsprocesser som använder sig av elektroforetiska metoder för att preparera proteinprover inför analys. Sådana processer som exempelvis Isoelektrisk Fokusering (IEF) fysiskt separerar proteinmolekylerna för att identifiera egenskaper som deras Isoelektriska Punktvärde (pI). Preparation av proteinprov förlitar sig till stor del på precisionen av teoretiskt beräknade pI värden. Det är därmed önskvärt att kunna beräkna pI värden som motsvarar observerade resultat från fraktioneringsprocesser. Förbättring av de teoretiskt beräknade pI värden gör det möjligt att förenkla analytiska processer som LC-MS. Det här projektet undersöker effektiviteten av enkodering av peptidattribut för att förbättra de beräknade pI värden jämfört med de konventionella beräkningarna baserat på Henderson-Hasselbalch ekvationen och pKa referensvärden. Enkodering av peptidattribut användes i samband med två olika optimeringsmodeller. Aminosyrorna från peptidsekvenserna separerades och enkoderas till olika k-mer undersekvenser som användes för anpassning av pKa referensvärden. Optimering av pKa referensvärden skapade en avsevärd förbättring i de beräknade pI värden jämfört med estimering enbart baserat på pKa referensvärden. De valda tillvägagångssätten visade att enkodering av peptidernas beståndsdelar markant förbättrar de beräknade pI värden på en grundläggande nivå. Framtida projekt borde överväga utbyggnaden av de diskuterade modellerna för att kunna fånga mer attribut från peptidsekvenserna för anpassning av pKa referensvärden och därmed förbättra beräkningen av pI värden.