An in vitro model system utilizing de-mineralized periodontium tissues was developed for investigating the molecular controls involved in the spatial deposition of minerals on collagenous tissues. Preferential mineral deposition was observed when the de-mineralized tissue sections were incubated in solutions containing a supersaturation of calcium and phosphate ions with respect to hydroxyapatite (HA). Energy dispersive X-Ray (EDX) analysis demonstrated that these minerals are likely to be octacalcium phosphate (OCP) or dicalcium phosphate dihydrate (DCPD); further characterization with a secondary technique is required to draw a more definitive conclusion. The role of collagen fibrils in mineralization was tested by removing all the non-collagenous components from the tissue sections with proteolytic enzymes and exposing them to similar mineralization conditions as the control samples. A substantially less amount of minerals were formed in these samples; this correlates well with the hypothesis in the literature that collagen fibrils alone cannot initiate mineral formation.

An in vitro model system utilizing de-mineralized periodontium tissues was developed for investigating the molecular controls involved in the spatial deposition of minerals on collagenous tissues. Preferential mineral deposition was observed when the de-mineralized tissue sections were incubated in solutions containing a supersaturation of calcium and phosphate ions with respect to hydroxyapatite (HA). Energy dispersive X-Ray (EDX) analysis demonstrated that these minerals are likely to be octacalcium phosphate (OCP) or dicalcium phosphate dihydrate (DCPD); further characterization with a secondary technique is required to draw a more definitive conclusion. The role of collagen fibrils in mineralization was tested by removing all the non-collagenous components from the tissue sections with proteolytic enzymes and exposing them to similar mineralization conditions as the control samples. A substantially less amount of minerals were formed in these samples; this correlates well with the hypothesis in the literature that collagen fibrils alone cannot initiate mineral formation.

Bone metastases are a frequent clinical complication associated with cancer. The aim of this PhD thesis was to set up a model system for the study of tumour cell – bone cell interactions in vitro, ex vivo and in vivo and to use this system to test the efficacy of a novel therapeutic agent for the treatment of osteolytic bone disease. Co-culture or conditioned medium studies using human or mouse cancer cell lines were used to develop an in vitro model system of tumour cell – bone cell interactions. This showed that osteolytic tumour cells enhance osteoclast formation, fusion and resorption through the production of various factors that act directly on osteoclasts and their precursors. And in addition, that osteolytic tumour cells also enhance osteoclastogenesis indirectly via increasing the production of RANKL in osteoblasts. Other effects on osteoblasts included reductions in differentiation, migration and adhesion. Successful ex vivo and in vivo models for the study of tumour – induced osteolysis were created using adapted organ cultures and intratibial injection techniques respectively. IGF-1 and its receptor are known to play important roles in both bone metabolism and breast cancer. Therefore a study of the effects of IGF-1 receptor inhibition on tumour cell – bone cell interactions was performed. In vitro studies showed that the novel IGF-1 receptor tyrosine kinase inhibitor PQIP significantly inhibited IGF-1 and breast cancer enhanced osteoclast formation. Western blot analysis suggested this may be due to the inhibition of both IGF-1 and cancer conditioned medium induced PI3k/Akt activation. Moreover, treatment of osteoblasts with PQIP inhibited cancer cell conditioned medium induced increases in RANKL production. Ex vivo studies using human MDA-MB-231 – mouse calvarial organ co-cultures demonstrated that MDA-MB-231 cells caused osteolysis and this was completely prevented by PQIP without affecting cancer cell viability. Furthermore, once daily oral administration of PQIP significantly decreased trabecular bone loss and reduced the size of osteolytic bone lesions following mouse 4T1 breast cancer cell intratibial injection in mice. Quantitative histomorphometry showed a significant reduction in breast cancer-induced osteoclast number and activity. Consistent with the significant inhibition of osteoblast differentiation, spreading, migration and bone nodule formation observed in vitro, PQIP also inhibited osteoblast number and bone formation in vivo. No inhibition of in vivo tumour volume was observed. These findings clearly suggest that oral PQIP treatment reduced the rate of cancer associated bone turnover. In conclusion, this thesis successfully demonstrates a model system for investigating tumour cell-bone cell interactions in vitro, ex vivo and in vivo. Using this model system I showed that pharmacologic inhibition of IGF-1 receptor kinase activity using PQIP inhibits osteoclast and osteoblast changes induced by breast cancer cells in vitro and in vivo and prevents osteolysis ex vivo and in vivo. This indicates that PQIP and its novel derivatives which are now in advanced clinical development may be of value in the treatment of osteolytic bone disease associated with breast cancer.

As Internet is penetrating into all spheres of life, the requirement of Lithuanian software is growing rapidly. Such penetration is reflected by popularity of distant studies and by stimulation of government means and various projects. Work with computers helps to acquire theoretical information more effectively and much faster. Created system helps to practically use information about enterprise activities, competition and profit opportunities. Paper analyzes the nature of software changes and the usage new systems. Also systems of market model are introduced and the results of realizations of market model are presented. The real advantage in experimental estimation is also discussed .

Tungsten oxide thin films were prepared by vacuum evaporation on surfaces of Pd(111), Cu(111), Cu(110) and Cu(100) single crystals and studied by RHEED, XPS and AFM methods. The tungsten oxide deposition was done at temperatures from 300 řC to 400 řC in UHV or in oxygen atmosphere. The best deposition conditions - substrate temperature of 400 řC and oxygen atmosphere - were found resulting in growth of epitaxial and only partially reduced thin films. Thin films grown on the Pd(111) and Cu(111) surfaces consisted of two phases: a nearly atomically flat phase with (100) epitaxial plane and a phase formed by three dimensional particles with (111) epitaxial plane. Thin film deposited on Cu(100) also consisted of two phases: a flat film with (100) epitaxial plane and self-organised 1D structures parallel to Cu[010] and Cu[001] directions. Thin film prepared on the Cu(110) surface contained solely 1D structures parallel to Cu[1-10] surface direction. Capability of the partially reduced thin films for oxidation was studied. We applied oxidation using RF oxygen plasma, O2 exposure at elevated temperature and exposure to atmosphere. Thermal stability of the WO3/Cu(110) system was also investigated by heating up to 620 řC.

Yes / Male sex hormones-androgens-regulate male physique development. Without androgen signaling, genetic males appear female. During puberty, increasing androgens harness the hair follicle's unique regenerative ability to replace many tiny vellus hairs with larger, darker terminal hairs (e.g., beard). Follicle response is epigenetically varied: some remain unaffected (e.g., eyelashes) or are inhibited, causing balding. How sex steroid hormones alter such developmental processes is unclear, despite high incidences of hormone-driven cancer, hirsutism, and alopecia. Unfortunately, existing development models are not androgen sensitive. Here, we use hair follicles to establish an androgen-responsive human organ culture model. We show that women's intermediate facial follicles respond to men's higher androgen levels by synthesizing more hair over several days, unlike donor-matched, androgen-insensitive, terminal follicles. We demonstrate that androgen receptors-androgen-activated gene transcription regulators-are required and are present in vivo within these follicles. This is the first human organ that involves multiple cell types that responds appropriately to hormones in prolonged culture, in a way which mirrors its natural behavior. Thus, intermediate hair follicles offer a hormone-switchable human model with exceptional, unique availability of genetically identical, but epigenetically hormone-insensitive, terminal follicles. This should enable advances in understanding sex steroid hormone signaling, gene regulation, and developmental and regenerative systems and facilitate better therapies for hormone-dependent disorders.

The expansion of gene-specific trinucleotide repeats is responsible for a growing list of human disorders, including myotonic dystrophy type 1 (DM1). Repeat instability for most of these disorders, including DM1, is characterized by complex patterns of inherited and ongoing tissue-specific instability and pathogenesis. While the mechanistic basis behind the unique locus-specific instability of trinucleotide repeats is currently unknown, DNA metabolic processes are likely to play a role. My thesis involves investigating the contribution of DNA replication to the trinucleotide instability of myotonic dystrophy type 1. Herein I have designed an in vivo primate model system, based on the SV40 replication system, to assess the contribution of DNA replication to DM1 repeat instability. This system allows the assessment, under controlled conditions, and manipulation of variables that may affect replication-associated repeat instability, under a primate cellular system. Using the SV40 model system, I not only confirmed previous observations that repeat length and replication direction affect repeat instability, but also for the first time determined that the location of the replication origin relative to the repeat tract plays an important role in repeat instability. This novel observation allowed for the development of a fork-shift model of repeat instability, in which cis-elements adjacent to the repeat tract affect replication, in turn altering the propensity for repeat instability. To further my study of DNA replication in DM1 repeat instability, I have mapped the origin of replication adjacent to the DM1 locus in human patient cells and the tissues of DM1 transgenic mice actively undergoing repeat instability. The position of the replication origins adjacent to the repeat tract at the DM1 locus places several known cis-elements, including CTCF binding sites, in a position to alter replication as predicted by the fork-shift model. My analysis of the CTCF sites showed them capable of altering replication and repeat instability at the DM1 locus. Taken together these results suggest that the placement of replication origins, repeat tracts and cis-elements, may mark trinucleotide repeat tracts, such as the DM1, for locus-, tissue- and development-specific replication-associated repeat instability.

The transition to multicellularity is a major step in the evolution of complex life. The first steps in this transition are poorly understood because multicellularity evolved long ago, and transitional forms have been lost to extinction. Previous studies developed a novel microbial model system in which simple multicellularity could be evolved de novo (Ratcliff et al., 2012). By evolving our snowflake yeast to undergo sexual reproduction we hypothesized that sex created variation in key multicellular traits, which spurs multicellular adaptation. In our 'snowflake yeast' model system, two traits are of central importance: cluster size, and programmed cell death (apoptosis). Apoptosis previously evolved to regulate cluster size, by acting as break points within clusters, allowing them to modify the size and number of multicellular propagules they produce. In prior experiments, this only develops after yeast have evolved to form large clusters. Prior experiments in the lab demonstrated that the longer snowflake yeast have been evolving, the greater the fitness benefit provided by sex. Here we examine whether this is due to sex creating greater amounts of diversity in the traits of post-sex offspring in more highly evolved multicellular yeast, allowing post-recombination offspring to 'fine tune' their multicellular traits. By using flow cytometry, we collected data on our multicellular traits. By gathering the biomass mean of the cluster size in each population and staining the cells with propidium iodide to determine the apoptotic tendencies of our cells we were able to compare our outcomes to the pre-sex ancestor, and we determined there was no increase in variation. Although apoptosis did not have an increase in variation due to sex, it created a variation in cluster size; the variation was seen in the population W8. This still supports our hypothesis that sex creates variation in multicellular traits, which allows for rapid adaptation.

Currently, there exists a great deal of uncertainty regarding atmospheric aerosols and the role that they play within the Earth’s atmosphere. It is known that atmospheric aerosols can play a role in the Earth’s climate by scattering and absorbing solar radiation or acting as a cloud condensation nuclei. The purpose of this work is to obtain an improved understanding of the chemistry of atmospheric aerosols to better determine their impacts the environment, air quality, and climate. This work revolves around one specific type of atmospheric aerosol, i.e. sea spray aerosol. Sea spray aerosol is generated via breaking waves, through wind-driven mechanisms. Ocean water covers roughly 71% of the Earth’s surface, and from this over 1300 Tg of sea spray aerosols is emitted into the atmosphere every year. However, until recently, the study of sea spray was very challenging and often inconclusive due to the inability to filter background particles out. In this work, the understanding of sea spray aerosol is progressed by taking a two-pronged approach. First, this work focuses on the study of model systems of simple ocean surfactants and NaCl and the change in chemistry that occurs when the two are in the presence of each other. Second, sea spray samples generated during a biological bloom are isolated and analyzed. Using this two pronged approach, it is shown that model systems can provide supporting evidence for hypotheses created from trends discovered in more complex samples. Finally, common aerosol generation, storage, and analysis techniques are studied in order to improve our understanding of their effects on aerosol particles.

The expansion of gene-specific trinucleotide repeats is responsible for a growing list of human disorders, including myotonic dystrophy type 1 (DM1). Repeat instability for most of these disorders, including DM1, is characterized by complex patterns of inherited and ongoing tissue-specific instability and pathogenesis. While the mechanistic basis behind the unique locus-specific instability of trinucleotide repeats is currently unknown, DNA metabolic processes are likely to play a role. My thesis involves investigating the contribution of DNA replication to the trinucleotide instability of myotonic dystrophy type 1. Herein I have designed an in vivo primate model system, based on the SV40 replication system, to assess the contribution of DNA replication to DM1 repeat instability. This system allows the assessment, under controlled conditions, and manipulation of variables that may affect replication-associated repeat instability, under a primate cellular system. Using the SV40 model system, I not only confirmed previous observations that repeat length and replication direction affect repeat instability, but also for the first time determined that the location of the replication origin relative to the repeat tract plays an important role in repeat instability. This novel observation allowed for the development of a fork-shift model of repeat instability, in which cis-elements adjacent to the repeat tract affect replication, in turn altering the propensity for repeat instability. To further my study of DNA replication in DM1 repeat instability, I have mapped the origin of replication adjacent to the DM1 locus in human patient cells and the tissues of DM1 transgenic mice actively undergoing repeat instability. The position of the replication origins adjacent to the repeat tract at the DM1 locus places several known cis-elements, including CTCF binding sites, in a position to alter replication as predicted by the fork-shift model. My analysis of the CTCF sites showed them capable of altering replication and repeat instability at the DM1 locus. Taken together these results suggest that the placement of replication origins, repeat tracts and cis-elements, may mark trinucleotide repeat tracts, such as the DM1, for locus-, tissue- and development-specific replication-associated repeat instability.