Hyperfine interactions in the new Fe-based superconducting structures and related magnetic phases

This thesis is devoted to the study of the hyperfine properties in iron-based superconductors and the synthesis of these compounds and related phases. During this work polycrystalline chalcogenide samples with stoichiometry 1:1 (FeTe1-χSχ, FeSe1-x) and pnictide samples with stoichiometry 1:2:2 (BaFe2(As1-χPχ)2, EuFe2(As1-x Px)2) were synthesized by solid-state reaction methods in vacuum and in a protecting Ar atmosphere. In several cases post-annealing in oxygen atmosphere was employed. The purity and superconducting properties of the obtained samples were checked with X-ray diffraction, SQUID and resistivity measurements. For studies of the magnetic properties of the investigated samples Mössbauer spectroscopy was used. Using low-temperature measurements around Tc and various values of the source velocity the hyperfine interactions were obtained and the magnetic and structural properties in the normal and superconducting states could be studied. Mössbauer measurements together with XRD characterization were also used for the detection of impurity phases. DFT calculations were used for the theoretical study of Mössbauer parameters for pnictide-based ᴻsamples BaFe2(As1-xPx)2 and EuFe2(As1-xPx)2.

Kalman filter for computational market dynamics

Kalman filter is a recursive mathematical power tool that plays an increasingly vital role in innumerable fields of study. The filter has been put to service in a multitude of studies involving both time series modelling and financial time series modelling. Modelling time series data in Computational Market Dynamics (CMD) can be accomplished using the Jablonska-Capasso-Morale (JCM) model. Maximum likelihood approach has always been utilised to estimate the parameters of the JCM model. The purpose of this study is to discover if the Kalman filter can be effectively utilized in CMD. Ensemble Kalman filter (EnKF), with 50 ensemble members, applied to US sugar prices spanning the period of January, 1960 to February, 2012 was employed for this work. The real data and Kalman filter trajectories showed no significant discrepancies, hence indicating satisfactory performance of the technique. Since only US sugar prices were utilized, it would be interesting to discover the nature of results if other data sets are employed.

Synthesis and secretion of transferrin by a bovine trabecular meshwork cell line

The trabecular meshwork (TM) is the main outflow pathway in the mammalian eye. Oxidative damage to TM cells has been suggested to be an important cause of impairment of TM functions, leading to deficient drainage of aqueous humor, with deleterious consequences to the eye. Transferrin, a metalloprotein involved in iron transport, has been characterized as an intrinsic eye protein. Since transferrin is implicated in the control of oxidative stress, the objective of the present study was to determine if a bovine TM cell line (CTOB) synthesizes and secretes transferrin. The CTOB cell line was cultured in the presence of 35S-methionine and the incubation medium was submitted to immunoprecipitation. Total RNAs from CTOB and isolated bovine TM (freshly isolated, incubated or not) were subjected to the reverse transcription-polymerase chain reaction and the amplification products were sequenced. Also, both CTOB and histological TM preparations were processed for transferrin immunolocalization. A labeled peptide of about 80 kDa, the expected size for transferrin, was immunopurified from CTOB samples obtained from the incubation assays. The reverse transcription-polymerase chain reaction and sequencing experiments detected the presence of transferrin mRNA in CTOB and isolated bovine TM. Reactivity to antibodies against transferrin was observed both in CTOB and TM. The results obtained in all of these experiments indicated that the TM is capable of synthesizing and secreting transferrin. The possible implications for the physiology of the eye are discussed.

Learning about brain physiology and complexity from the study of the epilepsies

The brain is a complex system, which produces emergent properties such as those associated with activity-dependent plasticity in processes of learning and memory. Therefore, understanding the integrated structures and functions of the brain is well beyond the scope of either superficial or extremely reductionistic approaches. Although a combination of zoom-in and zoom-out strategies is desirable when the brain is studied, constructing the appropriate interfaces to connect all levels of analysis is one of the most difficult challenges of contemporary neuroscience. Is it possible to build appropriate models of brain function and dysfunctions with computational tools? Among the best-known brain dysfunctions, epilepsies are neurological syndromes that reach a variety of networks, from widespread anatomical brain circuits to local molecular environments. One logical question would be: are those complex brain networks always producing maladaptive emergent properties compatible with epileptogenic substrates? The present review will deal with this question and will try to answer it by illustrating several points from the literature and from our laboratory data, with examples at the behavioral, electrophysiological, cellular and molecular levels. We conclude that, because the brain is a complex system compatible with the production of emergent properties, including plasticity, its functions should be approached using an integrated view. Concepts such as brain networks, graphics theory, neuroinformatics, and e-neuroscience are discussed as new transdisciplinary approaches dealing with the continuous growth of information about brain physiology and its dysfunctions. The epilepsies are discussed as neurobiological models of complex systems displaying maladaptive plasticity.

Gentamicin-induced preconditioning of proximal tubular LLC-PK1 cells stimulates nitric oxide production but not the synthesis of heat shock protein

Nephrotoxicity is the main side effect of antibiotics such as gentamicin. Preconditioning has been reported to protect against injuries as ischemia/reperfusion. The objective of the present study was to determine the effect of preconditioning with gentamicin on LLC-PK1 cells. Preconditioning was induced in LLC-PK1 cells by 24-h exposure to 2.0 mM gentamicin (G/IU). After 4 or 15 days of preconditioning, cells were again exposed to gentamicin (2.0 mM) and compared to untreated control or G/IU cells. Necrosis and apoptosis were assessed by acridine orange and HOESCHT 33346. Nitric oxide (NO) and endothelin-1 were assessed by the Griess method and available kit. Heat shock proteins were analyzed by Western blotting. After 15 days of preconditioning, LLC-PK1 cells exhibited a significant decrease in necrosis (23.5 ± 4.3 to 6.5 ± 0.3%) and apoptosis (23.5 ± 4.3 to 6.5 ± 2.1%) and an increase in cell proliferation compared to G/IU. NO (0.177 ± 0.05 to 0.368 ± 0.073 µg/mg protein) and endothelin-1 (1.88 ± 0.47 to 2.75 ± 0.53 pg/mL) production significantly increased after 15 days of preconditioning compared to G/IU. No difference in inducible HSP 70, constitutive HSC 70 or HSP 90 synthesis in tubular cells was observed after preconditioning with gentamicin. The present data suggest that preconditioning with gentamicin has protective effects on proximal tubular cells, that involved NO synthesis but not reduction of endothelin-1 or production of HSP 70, HSC 70, or HSP 90. We conclude that preconditioning could be a useful tool to prevent the nephrotoxicity induced by gentamicin.

Differences in synthesis and absorption of cholesterol of two effective lipid-lowering therapies

Effective statin therapy is associated with a marked reduction of cardiovascular events. However, the explanation for full benefits obtained for LDL cholesterol targets by combined lipid-lowering therapy is controversial. Our study compared the effects of two equally effective lipid-lowering strategies on markers of cholesterol synthesis and absorption. A prospective, open label, randomized, parallel design study, with blinded endpoints, included 116 subjects. We compared the effects of a 12-week treatment with 40 mg rosuvastatin or the combination of 40 mg simvastatin/10 mg ezetimibe on markers of cholesterol absorption (campesterol and β-sitosterol), synthesis (desmosterol), and their ratios to cholesterol. Both therapies similarly decreased total and LDL cholesterol, triglycerides and apolipoprotein B, and increased apolipoprotein A1 (P < 0.05 vs baseline for all). Simvastatin/ezetimibe increased plasma desmosterol (P = 0.012 vs baseline), and decreased campesterol and β-sitosterol (P < 0.0001 vs baseline for both), with higher desmosterol (P = 0.007) and lower campesterol and β-sitosterol compared to rosuvastatin, (P < 0.0001, for both). In addition, rosuvastatin increased the ratios of these markers to cholesterol (P < 0.002 vs baseline for all), whereas simvastatin/ezetimibe significantly decreased the campesterol/cholesterol ratio (P = 0.008 vs baseline) and tripled the desmosterol/cholesterol ratio (P < 0.0001 vs baseline). The campesterol/cholesterol and β-sitosterol/cholesterol ratios were lower, whereas the desmosterol/cholesterol ratio was higher in patients receiving simvastatin/ezetimibe (P < 0.0001 vs rosuvastatin, for all). Pronounced differences in markers of cholesterol absorption and synthesis were observed between two equally effective lipid-lowering strategies.

Adrenomedullin and adrenotensin regulate collagen synthesis and proliferation in pulmonary arterial smooth muscle cells

To understand the pathophysiological mechanisms of pulmonary arterial smooth muscle cell (PASMC) proliferation and extracellular-matrix accumulation in the development of pulmonary hypertension and remodeling, this study determined the effects of different doses of adrenomedullin (ADM) and adrenotensin (ADT) on PASMC proliferation and collagen synthesis. The objective was to investigate whether extracellular signal-regulated kinase (ERK1/2) signaling was involved in ADM- and ADT-stimulated proliferation of PASMCs in 4-week-old male Wistar rats (body weight: 100-150 g, n=10). The proliferation of PASMCs was examined by 5-bromo-2-deoxyuridine incorporation. A cell growth curve was generated by the Cell Counting Kit-8 method. Expression of collagen I, collagen III, and phosphorylated ERK1/2 (p-ERK1/2) was evaluated by immunofluorescence. The effects of different concentrations of ADM and ADT on collagen I, collagen III, and p-ERK1/2 protein expression were determined by immunoblotting. We also investigated the effect of PD98059 inhibition on the expression of p-ERK1/2 protein by immunoblotting. ADM dose-dependently decreased cell proliferation, whereas ADT dose-dependently increased it; and ADM and ADT inhibited each other with respect to their effects on the proliferation of PASMCs. Consistent with these results, the expression of collagen I, collagen III, and p-ERK1/2 in rat PASMCs decreased after exposure to ADM but was upregulated after exposure to ADT. PD98059 significantly inhibited the downregulation by ADM and the upregulation by ADT of p-ERK1/2 expression. We conclude that ADM inhibited, and ADT stimulated, ERK1/2 signaling in rat PASMCs to regulate cell proliferation and collagen expression.

Changes in cardiac aldosterone and its synthase in rats with chronic heart failure: an intervention study of long-term treatment with recombinant human brain natriuretic peptide

The physiological mechanisms involved in isoproterenol (ISO)-induced chronic heart failure (CHF) are not fully understood. In this study, we investigated local changes in cardiac aldosterone and its synthase in rats with ISO-induced CHF, and evaluated the effects of treatment with recombinant human brain natriuretic peptide (rhBNP). Sprague-Dawley rats were divided into 4 different groups. Fifty rats received subcutaneous ISO injections to induce CHF and the control group (n=10) received equal volumes of saline. After establishing the rat model, 9 CHF rats received no further treatment, rats in the low-dose group (n=8) received 22.5 μg/kg rhBNP and those in the high-dose group (n=8) received 45 μg/kg rhBNP daily for 1 month. Cardiac function was assessed by echocardiographic and hemodynamic analysis. Collagen volume fraction (CVF) was determined. Plasma and myocardial aldosterone concentrations were determined using radioimmunoassay. Myocardial aldosterone synthase (CYP11B2) was detected by quantitative real-time PCR. Cardiac function was significantly lower in the CHF group than in the control group (P<0.01), whereas CVF, plasma and myocardial aldosterone, and CYP11B2 transcription were significantly higher than in the control group (P<0.05). Low and high doses of rhBNP significantly improved hemodynamics (P<0.01) and cardiac function (P<0.05) and reduced CVF, plasma and myocardial aldosterone, and CYP11B2 transcription (P<0.05). There were no significant differences between the rhBNP dose groups (P>0.05). Elevated cardiac aldosterone and upregulation of aldosterone synthase expression were detected in rats with ISO-induced CHF. Administration of rhBNP improved hemodynamics and ventricular remodeling and reduced myocardial fibrosis, possibly by downregulating CYP11B2 transcription and reducing myocardial aldosterone synthesis.

Structural and Computational Existence Results for Multidimensional Subshifts

Symbolic dynamics is a branch of mathematics that studies the structure of infinite sequences of symbols, or in the multidimensional case, infinite grids of symbols. Classes of such sequences and grids defined by collections of forbidden patterns are called subshifts, and subshifts of finite type are defined by finitely many forbidden patterns. The simplest examples of multidimensional subshifts are sets of Wang tilings, infinite arrangements of square tiles with colored edges, where adjacent edges must have the same color. Multidimensional symbolic dynamics has strong connections to computability theory, since most of the basic properties of subshifts cannot be recognized by computer programs, but are instead characterized by some higher-level notion of computability. This dissertation focuses on the structure of multidimensional subshifts, and the ways in which it relates to their computational properties. In the first part, we study the subpattern posets and Cantor-Bendixson ranks of countable subshifts of finite type, which can be seen as measures of their structural complexity. We show, by explicitly constructing subshifts with the desired properties, that both notions are essentially restricted only by computability conditions. In the second part of the dissertation, we study different methods of defining (classes of ) multidimensional subshifts, and how they relate to each other and existing methods. We present definitions that use monadic second-order logic, a more restricted kind of logical quantification called quantifier extension, and multi-headed finite state machines. Two of the definitions give rise to hierarchies of subshift classes, which are a priori infinite, but which we show to collapse into finitely many levels. The quantifier extension provides insight to the somewhat mysterious class of multidimensional sofic subshifts, since we prove a characterization for the class of subshifts that can extend a sofic subshift into a nonsofic one.

Synthesis of Short Oligonucleotides on a Soluble Support by the Phosphoramidite Method

In the last decades, the chemical synthesis of short oligonucleotides has become an important aspect of study due to the discovery of new functions for nucleic acids such as antisense oligonucleotides (ASOs), aptamers, DNAzymes, microRNA (miRNA) and small interfering RNA (siRNA). The applications in modern therapies and fundamental medicine on the treatment of different cancer diseases, viral infections and genetic disorders has established the necessity to develop scalable methods for their cheaper and easier industrial manufacture. While small scale solid-phase oligonucleotide synthesis is the method of choice in the field, various challenges still remain associated with the production of short DNA and RNA-oligomers in very large quantities. On the other hand, solution phase synthesis of oligonucleotides offers a more predictable scaling-up of the synthesis and is amenable to standard industrial manufacture techniques. In the present thesis, various protocols for the synthesis of short DNA and RNA oligomers have been studied on a peracetylated and methylated β-cyclodextrin, and also on a pentaerythritol-derived support. On using the peracetylated and methylated β-cyclodextrin soluble supports, the coupling cycle was simplified by replacement of the typical 5′-O-(4,4′-dimethoxytrityl) protecting group with an acid-labile acetal-protected 5′-O-(1-methoxy-1-methylethyl) group, which upon acid-catalyzed methanolysis released easily removable volatile products. For this reason monomeric building blocks 5′-O-(1-methoxy-1-methylethyl) 3′-(2-cyano-ethyl-N,N-diisopropylphosphoramidite) were synthesized. Alternatively, on using the precipitative pentaerythritol support, novel 2´-O-(2-cyanoethyl)-5´-O-(1-methoxy-1-methylethyl) protected phosphoramidite building blocks for RNA synthesis have been prepared and their applicability by the synthesis of a pentamer was demonstrated. Similarly, a method for the preparation of short RNAs from commercially available 5´-O-(4,4´-dimethoxytrityl)-2´-O-(tert-butyldimethyl-silyl)ribonucleoside 3´-(2-cyanoethyl-N,N-diisopropylphosphoramidite) building blocks has been developed

Integration of marketing research data in new product development. Case study: Food industry company

The aim of this master’s thesis is to provide a real life example of how marketing research data is used by different functions in the NPD process. In order to achieve this goal, a case study in a company was implemented where gathering, analysis, distribution and synthesis of marketing research data in NPD were studied. The main research question was formulated as follows: How is marketing research data integrated and used by different company functions in the NPD process? The theory part of the master’s thesis was focused on the discussion of the marketing function role in NPD, use of marketing research particularly in the food industry, as well as issues related to the marketing/R&D interface during the NPD process. The empirical part of the master’s thesis was based on qualitative explanatory case study research. Individual in-depth interviews with company representatives, company documents and online research were used for data collection and analyzed through triangulation method. The empirical findings advocate that the most important marketing data sources at the concept generation stage of NPD are: global trends monitoring, retailing audit and consumers insights. These data sets are crucial for establishing the potential of the product on the market and defining the desired features for the new product to be developed. The findings also suggest the example of successful crossfunctional communication during the NPD process with formal and informal communication patterns. General managerial recommendations are given on the integration in NPD of a strategy, process, continuous improvement, and motivated cross-functional product development teams.

Computational fluid dynamics evaluation of liquid food thermal process in a brick shaped package

Food processes must ensure safety and high-quality products for a growing demand consumer creating the need for better knowledge of its unit operations. The Computational Fluid Dynamics (CFD) has been widely used for better understanding the food thermal processes, and it is one of the safest and most frequently used methods for food preservation. However, there is no single study in the literature describing thermal process of liquid foods in a brick shaped package. The present study evaluated such process and the influence of its orientation on the process lethality. It demonstrated the potential of using CFD to evaluate thermal processes of liquid foods and the importance of rheological characterization and convection in thermal processing of liquid foods. It also showed that packaging orientation does not result in different sterilization values during thermal process of the evaluated fluids in the brick shaped package.

Genetic variability for synthesis of bioactive compounds in peppers (Capsicum annuum) from Brazil

AbstractThe objective of this study was to evaluate the genetic variability for synthesis of bioactive compounds in pepper (Capsicum annuum, Solanaceae). Total phenolics, anthocyanins, carotenoids and antioxidant activity were evaluated in 14 accessions of Capsicum annuum from the Capsicum Genebank of Embrapa Temperate Agriculture (Pelotas – RS, Brazil). Thirty plants of each accession were cultivated in the field during spring and summer. The experimental design was a complete randomized block with 14 treatments (accessions) and three replications. The laboratory evaluations followed the same experimental design to field, but with two repetitions more. Seeds were discarded and opposite longitudinal portions of fruits were manually prepared for chemical analyzes. The data obtained showed high genetic variability for phenolics, anthocyanins, carotenoids and antioxidant activity. The P39, P77, P119, P143 and P302 accessions exhibited the highest levels of antioxidants, which are strongly indicated to be used in breeding programs of Capsicum peppers.

Blue and Uv-Emitting Upconversion Nanoparticles: Synthesis and (Bio) Analytical Applications.

Rare-earth based upconverting nanoparticles (UCNPs) have attracted much attention due to their unique luminescent properties. The ability to convert multiple photons of lower energy to ones with higher energy through an upconversion (UC) process offers a wide range of applications for UCNPs. The emission intensities and wavelengths of UCNPs are important performance characteristics, which determine the appropriate applications. However, insufficient intensities still limit the use of UCNPs; especially the efficient emission of blue and ultraviolet (UV) light via upconversion remains challenging, as these events require three or more near-infrared (NIR) photons. The aim of the study was to enhance the blue and UV upconversion emission intensities of Tm3+ doped NaYF4 nanoparticles and to demonstrate their utility in in vitro diagnostics. As the distance between the sensitizer and the activator significantly affect the energy transfer efficiency, different strategies were explored to change the local symmetry around the doped lanthanides. One important strategy is the intentional co-doping of active (participate in energy transfer) or passive (do not participate in energy transfer) impurities into the host matrix. The roles of doped passive impurities (K+ and Sc3+) in enhancing the blue and UV upconversions, as well as in influencing the intense UV upconversion emission through excess sensitization (active impurity) were studied. Additionally, the effects of both active and passive impurity doping on the morphological and optical performance of UCNPs were investigated. The applicability of UV emitting UCNPs as an internal light source for glucose sensing in a dry chemistry test strip was demonstrated. The measurements were in agreement with the traditional method based on reflectance measurements using an external UV light source. The use of UCNPs in the glucose test strip offers an alternative detection method with advantages such as control signals for minimizing errors and high penetration of the NIR excitation through the blood sample, which gives more freedom for designing the optical setup. In bioimaging, the excitation of the UCNPs in the transparent IR region of the tissue permits measurements, which are free of background fluorescence and have a high signal-to-background ratio. In addition, the narrow emission bandwidth of the UCNPs enables multiplexed detections. An array-in-well immunoassay was developed using two different UC emission colours. The differentiation between different viral infections and the classification of antibody responses were achieved based on both the position and colour of the signal. The study demonstrates the potential of spectral and spatial multiplexing in the imaging based array-in-well assays.

Synthesis and characterization of nanoperforated metal oxide thin films

For advanced devices in the application fields of data storage, solar cell and biosensing, one of the major challenges to achieve high efficiency is the fabrication of nanopatterned metal oxide surfaces. Such surfaces often require both precise structure at the nanometer scale and controllable patterned structure at the macro scale. Nowadays, the dominating candidates to fabricate nanopatterned surfaces are the lithographic technique and block-copolymer masks, most of which are unfortunately costly and inefficient. An alternative bottom-up approach, which involves organic/inorganic self-assembly and dip-coating deposition, has been studied intensively in recent years and has proven to be an effective technique for the fabrication of nanoperforated metal oxide thin films. The overall objective of this work was to optimize the synthesis conditions of nanoperforated TiO2 (NP-TiO2) thin films, especially to be compatible with mixed metal oxide systems. Another goal was to develop fabrication and processing of NP-TiO2 thin films towards largescale production and seek new applications for solar cells and biosensing. Besides the traditional dip-coating and drop-casting methods, inkjet printing was used to prepare thin films of metal oxides, with the advantage of depositing the ink onto target areas, further enabling cost-effective fabrication of micro-patterned nanoperforated metal oxide thin films. The films were characterized by water contact angle determination, Atomic Force Microscopy, Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and Grazing Incidence XRay Diffraction. In this study, well-ordered zinc titanate nanoperforated thin films with different Zn/Ti ratios were produced successfully with zinc precursor content up to 50 mol%, and the dominating phase was Zn2Ti3O8. NP-TiO2 structures were also obtained by a cost-efficient means, namely inkjet printing, at both ambient temperature and 60 °C. To further explore new biosensing applications of nanoperforated oxide thin films, inkjet printing was used for the fabrication of both continuous and patterned polymeric films onto NP-TiO2 and perfluorinated phosphate functionalized NP-TiO2 substrates, respectively. The NP-TiO2 films can be also functionalized with a fluoroalkylsilane, resulting in hydrophobic surfaces on both titania and silica. The surface energy contrast in the nanoperforations can be tuned by irradiating the films with UV light, which provides ideal model systems for wettability studies.