Enhancing performance of paper coatings by tailor-made plastic pigments

The paper industry is constantly looking for new ideas for improving paper products while competition and raw material prices are increasing. Many paper products are pigment coated. Coating layer is the top layer of paper, thus by modifying coating pigment also the paper itself can be altered and value added to the final product. In this thesis, synthesis of new plastic and hybrid pigments and their performance in paper and paperboard coating is reported. Two types of plastic pigments were studied: core-shell latexes and solid beads of maleimide copolymers. Core-shell latexes with partially crosslinked hydrophilic polymer core of poly(n-butyl acrylate-co-methacrylic acid) and a hard hydrophobic polystyrene shell were prepared to improve the optical properties of coated paper. In addition, the effect of different crosslinkers was analyzed and the best overall performance was achieved by the use of ethylene glycol dimethacrylate (EGDMA). Furthermore, the possibility to modify core-shell latex was investigated by introducing a new polymerizable optical brightening agent, 1-[(4-vinylphenoxy)methyl]-4-(2-henylethylenyl)benzene which gave promising results. The prepared core-shell latex pigments performed smoothly also in pilot coating and printing trials. The results demonstrated that by optimizing polymer composition, the optical and surface properties of coated paper can be significantly enhanced. The optimal reaction conditions were established for thermal imidization of poly(styrene-co-maleimide) (SMI) and poly(octadecene-co-maleimide) (OMI) from respective maleic anhydride copolymer precursors and ammonia in a solvent free process. The obtained aqueous dispersions of nanoparticle copolymers exhibited glass transition temperatures (Tg) between 140-170ºC and particle sizes from 50-230 nm. Furthermore, the maleimide copolymers were evaluated in paperboard coating as additional pigments. The maleimide copolymer nanoparticles were partly imbedded into the porous coating structure and therefore the full potential of optical property enhancement for paperboard was not achieved by this method. The possibility to modify maleimide copolymers was also studied. Modifications were carried out via N-substitution by replacing part of the ammonia in the imidization reaction with amines, such as triacetonediamine (TAD), aspartic acid (ASP) and fluorinated amines (2,2,2- trifluoroethylamine, TFEA and 2,2,3,3,4,4,4-heptafluorobuthylamine, HFBA). The obtained functional nanoparticles varied in size between 50-217 nm and their Tg from 150-180ºC. During the coating process the produced plastic pigments exhibited good runnability. No significant improvements were achieved in light stability with TAD modified copolymers whereas nanoparticles modified with aspartic acid and those containing fluorinated groups showed the desired changes in surface properties of the coated paperboard. Finally, reports on preliminary studies with organic-inorganic hybrids are presented. The hybrids prepared by an in situ polymerization reaction consisted of 30 wt% poly(styrene- co-maleimide) (SMI) and high levels of 70 wt% inorganic components of kaolin and/or alumina trihydrate. Scanning Electron Microscopy (SEM) images and characterization by Fourier Transform Infrared Spcetroscopy (FTIR) and X-Ray Diffraction (XRD) revealed that the hybrids had conventional composite structure and inorganic components were covered with precipitated SMI nanoparticles attached to the surface via hydrogen bonding. In paper coating, the hybrids had a beneficial effect on increasing gloss levels.

Rainfall erosivity for the State of Rio de Janeiro estimated by artificial neural network

The Artificial Neural Networks (ANNs) are mathematical models method capable of estimating non-linear response plans. The advantage of these models is to present different responses of the statistical models. Thus, the objective of this study was to develop and to test ANNs for estimating rainfall erosivity index (EI30) as a function of the geographical location for the state of Rio de Janeiro, Brazil and generating a thematic visualization map. The characteristics of latitude, longitude e altitude using ANNs were acceptable to estimating EI30 and allowing visualization of the space variability of EI30. Thus, ANN is a potential option for the estimate of climatic variables in substitution to the traditional methods of interpolation.

Economic analysis of cashew early dwarf Crop BRS - 189 depending on water levels and doses of potassium fertilization

Water and fertilizer among the production factors are the elements that most restrict the production of cashew. The precise amount of these factors is essential to the success of the crop yield. This research aimed to determine the best factor-product ratio and analyze technical and economic indicators, of productivity of the cashew clone BRS 189 (Anacardium occidentale) to production factors water and potassium. The experiment was conducted from May 2009 to December 2009 in an experimental area of 56.0 m x 112.0 m in the irrigated Curu - Pentecoste, located in the municipality of Pentecoste, Ceará, Brazil. Production factors water (W) and potassium (K) were the independent variables and productivity (Y), the dependent variable. Ten statistical models that have proven satisfactory for obtaining production function were tested. The marginal rate of substitution was obtained through the ratio of the potassium marginal physical product and the water marginal physical product. The most suited model to the conditions of the experiment was the quadratic polynomial without intercept and interaction. Considering that the price of the water was 0.10 R$ mm -1, the price of the potassium 2.19 R$ kg -1 and the price of the cashew 0.60 R$ kg-1, the amounts of water and K2O to obtain the maximum net income were 6,349.1 L plant-1 of water and 128.7 g plant -1year, -1 respectively. Substituting the values obtained in the production function, the maximum net income was achieved with a yield of 7,496.8 kg ha-1 of cashew.

Repair of segmental bone defects with fiber-reinforced composite: a study of material development and an animal model on rabbits

The Repair of segmental defects in load-bearing long bones is a challenging task because of the diversity of the load affecting the area; axial, bending, shearing and torsional forces all come together to test the stability/integrity of the bone. The natural biomechanical requirements for bone restorative materials include strength to withstand heavy loads, and adaptivity to conform into a biological environment without disturbing or damaging it. Fiber-reinforced composite (FRC) materials have shown promise, as metals and ceramics have been too rigid, and polymers alone are lacking in strength which is needed for restoration. The versatility of the fiber-reinforced composites also allows tailoring of the composite to meet the multitude of bone properties in the skeleton. The attachment and incorporation of a bone substitute to bone has been advanced by different surface modification methods. Most often this is achieved by the creation of surface texture, which allows bone growth, onto the substitute, creating a mechanical interlocking. Another method is to alter the chemical properties of the surface to create bonding with the bone – for example with a hydroxyapatite (HA) or a bioactive glass (BG) coating. A novel fiber-reinforced composite implant material with a porous surface was developed for bone substitution purposes in load-bearing applications. The material’s biomechanical properties were tailored with unidirectional fiber reinforcement to match the strength of cortical bone. To advance bone growth onto the material, an optimal surface porosity was created by a dissolution process, and an addition of bioactive glass to the material was explored. The effects of dissolution and orientation of the fiber reinforcement were also evaluated for bone-bonding purposes. The Biological response to the implant material was evaluated in a cell culture study to assure the safety of the materials combined. To test the material’s properties in a clinical setting, an animal model was used. A critical-size bone defect in a rabbit’s tibia was used to test the material in a load-bearing application, with short- and long-term follow-up, and a histological evaluation of the incorporation to the host bone. The biomechanical results of the study showed that the material is durable and the tailoring of the properties can be reproduced reliably. The Biological response - ex vivo - to the created surface structure favours the attachment and growth of bone cells, with the additional benefit of bioactive glass appearing on the surface. No toxic reactions to possible agents leaching from the material could be detected in the cell culture study when compared to a nontoxic control material. The mechanical interlocking was enhanced - as expected - with the porosity, whereas the reinforcing fibers protruding from the surface of the implant gave additional strength when tested in a bone-bonding model. Animal experiments verified that the material is capable of withstanding load-bearing conditions in prolonged use without breaking of the material or creating stress shielding effects to the host bone. A Histological examination verified the enhanced incorporation to host bone with an abundance of bone growth onto and over the material. This was achieved with minimal tissue reactions to a foreign body. An FRC implant with surface porosity displays potential in the field of reconstructive surgery, especially regarding large bone defects with high demands on strength and shape retention in load-bearing areas or flat bones such as facial / cranial bones. The benefits of modifying the strength of the material and adjusting the surface properties with fiber reinforcement and bone-bonding additives to meet the requirements of different bone qualities are still to be fully discovered.

Development of an environmentally friendly method of starch oxidation by hydrogen peroxide and a complex water-soluble Iron catalyst

Oxidized starch is a key component in the paper industry, where it is used as both surfacing sizer and filler. Large quantities are annually used for this purpose; however, the methods for the oxidation are not environmentally friendly. In our research, we have studied the possibility to replace the harmful oxidation agents, such as hypochlorite or iodates and transition metal catalysts, with a more environmentally friendly oxidant, hydrogen peroxide (H2O2), and a special metal complex catalyst (FePcS), of which only a small amount is needed. The work comprised batch and semi-batch studies by H2O2, ultrasound studies of starch particles, determination of low-molecular by-products and determination of the decomposition kinetics of H2O2 in the presence of starch and the catalyst. This resulted in a waste-free oxidation method, which only produces water and oxygen as side products. The starch oxidation was studied in both semi-batch and batch modes in respective to the oxidant (H2O2) addition. The semi-batch mode proved to yield a sufficient degree of substitution (COOH groups) for industrial purposes. Treatment of starch granules by ultrasound was found to improve the reactivity of starch. The kinetic results were found out to have a rather complex pattern – several oxidation phases were observed, apparently due to the fact that the oxidation reaction in the beginning only took place on the surface, whereas after a prolonged reaction time, partial degradation of the solid starch granules allowed further reaction in the interior parts. Batch-mode experiments enabled a more detailed study of the mechanisms of starch in the presence of H2O2 and the catalyst, but yielded less oxidized starch due to rapid decomposition of H2O2 due to its high concentrations. The effect of the solid-liquid (S/L) ratio in the reaction system was studied in batch experiments. These studies revealed that the presence of the catalyst and the starch enhance the H2O2 decomposition.

A phylogenetic study of canine parvovirus type 2c in midwestern Brazil

Since the late 1970s, canine parvovirus type 2 (CPV-2) has emerged as a causative agent of fatal severe acute hemorrhagic enteritis in dogs. To date, three antigenic types of CPV-2 were described worldwide (CPV-2a/b/c). This study was conducted to determine the variants of CPV-2 circulating in dogs from the Cuiabá Municipality in Midwestern Brazil. Out of 50 fecal samples, collected between 2009 and 2011, 27 tested positive for CPV-2. A 583 bp fragment of the VP2 gene was amplified by PCR, 13 representative samples were analyzed further by DNA sequencing. All strains were characterized as CPV-2c, displayed a low genetic variability although observed several amino acid substitution. These findings indicated that CPV-2c has been circulating in dogs from the Cuiabá Municipality in Midwestern Brazil.

Selective inhibition of human tankyrases

Tankyrases belong to the Diphtheria toxin-like ADP-ribosyltransferase (ARTD) enzyme superfamily, also known as poly(ADP-ribose) polymerases (PARPs). They catalyze a covalent post-translational modification reaction where they transfer ADP-ribose units from NAD+ to target proteins. Tankyrases are involved in many cellular processes and their roles in telomere homeostasis, Wnt signaling and in several diseases including cancers have made them interesting drug targets. In this thesis project, selective inhibition of human tankyrases was studied. A homogeneous fluorescence-based assay was developed to screen the compound libraries. The assay is inexpensive, operationally easy, and performs well according to the statistical analysis. Assay suitability was confirmed by screening a natural product library. Flavone was identified as the most potent inhibitor in the library and this motivated us to screen a larger flavonoid library. Results showed that flavones were indeed the best inhibitor of tankyrases among flavonoids. To further study the structure-activity relationship, a small library of flavones containing single substitution was screened and potency measurements allowed us to generate structure-activity relationship. Compounds containing substitutions at 4´-position were more potent in comparison to other substitutions, and importantly, hydrophobic groups improved isoenzyme selectivity as well as the potency. A flavone derivative containing a hydrophobic isopropyl group (compound 22), displayed 6 nM potency against TNKS1, excellent isoenzyme selectivity and Wnt signaling inhibition. Protein interactions with compounds were studied by solving complex crystal structures of the compounds with TNKS2 catalytic domain. A novel tankyrase inhibitor (IWR-1) was also crystallized in complex with TNKS2 catalytic domain. The crystal structure of TNKS2 in complex with IWR-1 showed that the compound binds to adenosine site and it was the first known ARTD inhibitor of this kind. To date, there is no structural information available about the substrate binding with any of the ARTD family members; therefore NAD+ was soaked with TNKS2 catalytic domain crystals. However, analysis of crystal structure showed that NAD+ was hydrolyzed to nicotinamide. Also, a co-crystal structure of NAD+ mimic compound, EB-47, was solved which was used to deduce some insights about the substrate interactions with the enzyme. Like EB-47, other ARTD1 inhibitors were also shown to inhibit tankyrases. It indicated that selectivity of the ARTD1 inhibitors should be considered as some of the effects in cells could come from tankyrase inhibition. In conclusion, the study provides novel information on tankyrase inhibition and presents new insight into the selectivity and potency of compounds.

Molecular Basis for Resistance to Fluazifop-P-Butyl in Itchgrass (Rottboellia cochinchinensis) from Costa Rica

Rottboellia cochinchinensis is an annual grass weed species known as itchgrass, or "caminadora" in America´s Spanish speaking countries, and has become a major and troublesome weed in several crops. The application of fluazifop-P-butyl at recommended rates (125 g a.i. ha-1) was observed to be failing to control itchgrass in a field in San José, Upala county, Alajuela province, Costa Rica. Plants from the putative resistant R. cochinchinensis population survived fluazifop-P-butyl when treated with 250 g a.i. ha-1 (2X label rate) at the three- to four-leaf stage under greenhouse conditions. PCR amplification and sequencing of partial carboxyl transferase domain (CT) of the acetyl-CoA carboxylase (ACCase) gene were used to determine the molecular mechanism of resistance. A single non-synonymous point mutation from TGG (susceptible plants) to TGC (putative resistant plants) that leads to a Trp-2027-Cys substitution was found. This Trp-2027-Cys mutation is known to confer resistance to all aryloxyphenoxyproprionate (APP) herbicides to which fluazifop-P-butyl belongs. To the best of our knowledge, this is the first report of fluazifop-P-butyl resistance and a mutation at position 2027 for a Costa Rican R. cochinchinensis population.

Techniques of radioautography for medical and biological research

Standard techniques for radioautography used in biological and medical research can be classified into three categories, i.e., macroscopic radioautography, light microscopic radioautography and electron microscopic radioautography. The routine techniques used in these three procedures are described. With regard to macroscopic radioautography, whole body radioautography is a standard technique which employs freezing and cryosectioning and can demonstrate organ distributions of both soluble and insoluble compounds. In contrast, in light and electron microscopic radioautography, soluble and insoluble techniques are separated. In order to demonstrate insoluble labeled compounds, conventional chemical fixations such as formalin for light microscopy or buffered glutaraldehyde and osmium tetroxide for both light and electron microscopy followed by dehydration, embedding and wet-mounting applications of radioautographic emulsions can be used. For the demonstration of soluble labeled compounds, however, cryotechniques such as cryofixation, cryosectioning, freeze-drying, freeze-substitution followed by dry-sectioning and dry-mounting radioautography should be employed both for light and electron microscopy. The outlines of these techniques, which should be utilized in various fields of biological and medical research, are described in detail

Susteinable steelmaking by process integration

Environmental issues, including global warming, have been serious challenges realized worldwide, and they have become particularly important for the iron and steel manufacturers during the last decades. Many sites has been shut down in developed countries due to environmental regulation and pollution prevention while a large number of production plants have been established in developing countries which has changed the economy of this business. Sustainable development is a concept, which today affects economic growth, environmental protection, and social progress in setting up the basis for future ecosystem. A sustainable headway may attempt to preserve natural resources, recycle and reuse materials, prevent pollution, enhance yield and increase profitability. To achieve these objectives numerous alternatives should be examined in the sustainable process design. Conventional engineering work cannot address all of these substitutes effectively and efficiently to find an optimal route of processing. A systematic framework is needed as a tool to guide designers to make decisions based on overall concepts of the system, identifying the key bottlenecks and opportunities, which lead to an optimal design and operation of the systems. Since the 1980s, researchers have made big efforts to develop tools for what today is referred to as Process Integration. Advanced mathematics has been used in simulation models to evaluate various available alternatives considering physical, economic and environmental constraints. Improvements on feed material and operation, competitive energy market, environmental restrictions and the role of Nordic steelworks as energy supplier (electricity and district heat) make a great motivation behind integration among industries toward more sustainable operation, which could increase the overall energy efficiency and decrease environmental impacts. In this study, through different steps a model is developed for primary steelmaking, with the Finnish steel sector as a reference, to evaluate future operation concepts of a steelmaking site regarding sustainability. The research started by potential study on increasing energy efficiency and carbon dioxide reduction due to integration of steelworks with chemical plants for possible utilization of available off-gases in the system as chemical products. These off-gases from blast furnace, basic oxygen furnace and coke oven furnace are mainly contained of carbon monoxide, carbon dioxide, hydrogen, nitrogen and partially methane (in coke oven gas) and have proportionally low heating value but are currently used as fuel within these industries. Nonlinear optimization technique is used to assess integration with methanol plant under novel blast furnace technologies and (partially) substitution of coal with other reducing agents and fuels such as heavy oil, natural gas and biomass in the system. Technical aspect of integration and its effect on blast furnace operation regardless of capital expenditure of new operational units are studied to evaluate feasibility of the idea behind the research. Later on the concept of polygeneration system added and a superstructure generated with alternative routes for off-gases pretreatment and further utilization on a polygeneration system producing electricity, district heat and methanol. (Vacuum) pressure swing adsorption, membrane technology and chemical absorption for gas separation; partial oxidation, carbon dioxide and steam methane reforming for methane gasification; gas and liquid phase methanol synthesis are the main alternative process units considered in the superstructure. Due to high degree of integration in process synthesis, and optimization techniques, equation oriented modeling is chosen as an alternative and effective strategy to previous sequential modelling for process analysis to investigate suggested superstructure. A mixed integer nonlinear programming is developed to study behavior of the integrated system under different economic and environmental scenarios. Net present value and specific carbon dioxide emission is taken to compare economic and environmental aspects of integrated system respectively for different fuel systems, alternative blast furnace reductants, implementation of new blast furnace technologies, and carbon dioxide emission penalties. Sensitivity analysis, carbon distribution and the effect of external seasonal energy demand is investigated with different optimization techniques. This tool can provide useful information concerning techno-environmental and economic aspects for decision-making and estimate optimal operational condition of current and future primary steelmaking under alternative scenarios. The results of the work have demonstrated that it is possible in the future to develop steelmaking towards more sustainable operation.

Crotoxin, the major toxin from the rattlesnake Crotalus durissus terrificus, inhibits ³H-choline uptake in guinea pig ileum

We examined the effect of crotoxin, the neurotoxic complex from the venom of the South American rattlesnake Crotalus durissus terrificus, on the uptake of ³H-choline in minces of smooth muscle myenteric plexus from guinea pig ileum. In the concentration range used (0.03-1 µM) and up to 10 min of treatment, crotoxin decreased ³H-choline uptake by 50-75% compared to control. This inhibition was time dependent and did not seem to be associated with the disruption of the neuronal membrane, because at least for the first 20 min of tissue exposure to the toxin (up to 1 µM) the levels of lactate dehydrogenase (LDH) released into the supernatant were similar to those of controls. Higher concentrations of crotoxin or more extensive incubation times with this toxin resulted in elevation of LDH activity detected in the assay supernatant. The inhibitory effect of crotoxin on ³H-choline uptake seems to be associated with its phospholipase activity since the equimolar substitution of Sr2+ for Ca2+ in the incubation medium or the modification of the toxin with p-bromophenacyl bromide substantially decreased this effect. Our results show that crotoxin inhibits ³H-choline uptake with high affinity (EC25 = 10 ± 5 nM). We suggest that this inhibition could explain, at least in part, the blocking effect of crotoxin on neurotransmission.

21-Hydroxylase deficiency in Brazil

We determined the frequency of large rearrangements and point mutations in 130 Brazilian patients with 21-hydroxylase deficiency and correlated genotype with phenotype. The frequency of CYP21 deletions was lower (4.4%) than in most of the previous series described, whereas the frequency of large gene conversions was similar to the frequency reported in the literature (6.6%). The most frequent point mutations were I2 splice (41.8% in salt wasting - SW), I172N (32.6% in simple virilizing - SV) and V281L (40.2% in the late onset form - LO). The frequency of the nine most common point mutations was similar to that reported for other countries. The 93 fully genotyped patients were classified into 3 mutation groups based on the degree of enzymatic activity (A<2%, B @ 2%, C>20%). In group A, 62% of cases presented the SW form; in group B, 96% the SV form, and in group C, 88% the LO form. We diagnosed 80% of the affected alleles after screening for large rearrangements and 15 point mutations. To diagnose these remaining alleles we sequenced the CYP21 gene of one patient with the SV form and identified a heterozygous G->A transition in codon 424. This mutation leads to a substitution of glycine by serine in a conserved region and was also found in a compound heterozygous state in 4 other patients. The mutation G424S presented a linkage disequilibrium with CYP21P and C4A gene deletions and HLA DR17, suggesting a probable founder effect. Search for the G424S mutation in other populations will reveal if it is restricted to the Brazilian patients or if it has a wider ethnic distribution.

Puuperäiset polymeerit synteettisten sideaineiden korvaajina

Tämän kandidaatintyön aiheena oli löytää biojalostamon näkökulmasta käyttökelpoisia tuotantoreittejä puuperäisistä materiaaleista bioperäisiin kemikaaleihin, joilla olisi mahdollista korvata synteettisiä sideaineita. Tällä hetkellä suurin osa sideaineista ja päällystemateriaaleista tuotetaan uusiutumattomista luonnonvaroista, kuten maakaasusta ja öljystä. Lopputuotteiden kierrätettävyyden ja vihreyden ohella yksi metsäteollisuuden tulevaisuuden trendejä on pyrkiä irti öljy- ja maakaasuriippuvuudesta. Muutoksella voidaan säästää sekä ympäristöä, että rahaa. Biopohjaisilla drop-in kemikaaleilla ja muilla biopohjaisilla vaihtoehdoilla tämä on mahdollista Tässä työssä tutkittiin ja havainnollistettiin mahdollisin tuotantoreitein useiden tällä hetkellä käytössä olevien sideaineiden korvaamista biopohjaisilla versioilla. Työ tehtiin kirjallisuustutkielmana, eikä siihen kuulunut laboratoriokokeita. Työn ensimmäisessä osassa painopiste on biojalostamossa ja dispersiopäällystyksessä. Toisessa osassa esitellään tällä hetkellä käytettyjä sideaineita ja niiden mahdollisia biopohjaisia korvaajia tuotantoreitteineen. Työn toissijainen tarkoitus oli selvittää lyhyesti mitä muita puuperäisiä komponentteja voidaan käyttää suoraan paperin ja kartongin päällystämiseen. Viimeiseksi on esitelty vielä lyhyesti kaupallisesti käytössä olevia biomuoveja ja päällysteitä.

Detection of somatic mutations of the PIG-A gene in Brazilian patients with paroxysmal nocturnal hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal syndrome characterized by intravascular hemolysis mediated by complement, thrombotic events and alterations in hematopoiesis. Basically, the molecular events which underlie the complexity of the syndrome consist of the absence of the glycosylphosphatidylinositol (GPI) anchor as a consequence of somatic mutations in the PIG-A gene, located on the X chromosome. The GPI group is responsible for the attachment of many proteins to the cytoplasmic membrane. Two of them, CD55 and CD59, have a major role in the inhibition of the action of complement on the cellular membrane of blood cells. The absence of GPI biosynthesis can lead to PNH. Since mutations in the PIG-A gene are always present in patients with PNH, the aim of this study was to characterize the mutations in the PIG-A gene in Brazilian patients. The analysis of the PIG-A gene was performed using DNA samples derived from bone marrow and peripheral blood. Conformation-sensitive gel electrophoresis was used for screening the mutation and sequencing methods were used to identify the mutations. Molecular analysis permitted the identification of three point mutations in three patients: one G->A transition in the 5' portion of the second intron, one T->A substitution in the second base of codon 430 (Leu430->stop), and one deletion deltaA in the third base of codon 63. This study represents the first description of mutations in the PIG-A gene in a Brazilian population.