Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-08-09T15:52:23Z No. of bitstreams: 2 Dissertação - Maysa Magalhães Vaz - 2015.pdf: 1556093 bytes, checksum: 261abbdf2b113a9412b9c96e41d826a4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-08-09T15:54:38Z (GMT) No. of bitstreams: 2 Dissertação - Maysa Magalhães Vaz - 2015.pdf: 1556093 bytes, checksum: 261abbdf2b113a9412b9c96e41d826a4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-08-09T15:54:38Z (GMT). No. of bitstreams: 2 Dissertação - Maysa Magalhães Vaz - 2015.pdf: 1556093 bytes, checksum: 261abbdf2b113a9412b9c96e41d826a4 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-03-20 / Tooth bleaching is the first alternative for obtaining a harmonious smile. However, the bleaching material can cause damage to the pulp. This study aimed to characterize the human pulp response before different bleaching techniques. Twenty-nine volunteers (n = 29) were included in the study and divided into 3 groups. The human third molars with extraction indication of these patients were used. The groups were divided according to the bleaching technique performed: control group - was not performed any bleaching technique (n = 7); Group 01- home bleaching with carbamide peroxide 15% (n = 10); Group 02- professional whitening with hydrogen peroxide 38% (n = 12). The teeth were extracted and the pulp removed and stained with hematoxylin and eosin (H & E) or subjected to immunohistochemistry for microscopic evaluation of immunostained cells and analysis. In microscopic analysis, the groups were evaluated for intensity of the inflammatory infiltrate, collagen degradation and organization of the pulp tissue. For immunohistochemicaltechnique have been identified: mast cells (tryptase positive), macrophages (CD68 +) and blood vessels (CD 31+). Data were submitted to descriptive analysis and, as a result, processed by the statistical program (Chi Square to the criteria evaluated the technique of H & E and Kruskal-Wallis followed by Mann Whitney for the data of immunohistochemistry: values less than 0, 05 were considered statistically significant). The microscopic analysis, groups showed statistically significant differences for the intensity criterion of the inflammatory infiltrate (p <0.05) but not for collagen degradation (p> 0.05) and organization of the pulp tissue (p> 0.05). The findings of immunohistochemistry showed statistical difference between the density of macrophages, being higher in Group 2. When compared in pairs, there was the Group 2 for the remaining difference (p <0.05) but not between Groups Control and domesticated (p> 0.05). The blood vessels presented with similar density among the three groups (p> 0.05) and were not found mast cells. It was concluded that the professional whitening results in a more intense inflammatory response and increased pulp damage when compared to home bleaching in molars. / O clareamento dental é a primeira alternativa para a obtenção de um sorriso harmonioso. Contudo, sabe-se que o material clareador pode ocasionar danos à polpa. Este estudo objetivou caracterizar a resposta pulpar humana frente a diferentes técnicas de clareamento. Vinte e nove voluntários (n=29), divididos em 3 grupos, foram incluídos na pesquisa e deles foram utilizados terceiros molares humanos hígidos com indicação de exodontia. Os grupos foram divididos de acordo com a técnica de clareamento realizada: Grupo Controle –não foi realizada nenhuma técnica de clareamento (n=7); Grupo 01- clareamento caseiro com peróxido de carbamida 15% (n=10); Grupo 02- clareamento profissional com peróxido de hidrogênio 38% (n=12). Os dentes foram extraídos e as polpas removidas e coradas por hematoxilina e eosina(H&E) ou submetidas àimuno-histoquímica, para análise microscópica e avaliação das células imunomarcadas. Na análise microscópica,os grupos foram avaliados quanto à intensidade do infiltrado inflamatório, degradação de colágeno e organização do tecido pulpar. Pela técnica de imuno-histoquímica, foramidentificados: mastócitos (triptase positivos), macrófagos (CD68+) e vasos sanguíneos (CD 31+). Os dados foram submetidos à análise descritiva e, na sequência, processados pelo programa estatístico (Qui Quadrado para os critérios avaliados com a técnica de H&E e Kruskall-Wallis seguido de Mann Whitney para os dados da imuno-histoquímica- os valores menores que 0,05 foram considerados estatisticamente significativos). Na avaliação microscópica, grupos mostraram diferença estatística para o critério intensidade do infiltrado inflamatório (p<0,05), mas não para degradação do colágeno (p>0,05) e organização do tecido pulpar (p>0,05). Os achados da imuno-histoquímica mostraram diferença estatística entre a densidade de macrófagos, sendo maior no Grupo 2. Quando comparados aos pares, observou-se diferença do Grupo 2 para os demais (p<0,05), mas não entre os Grupos Controle e Caseiro(p>0,05). Os vasos sanguíneos apresentaram-se com densidade semelhante entre os três grupos avaliados (p>0,05) e não foram encontrados mastócitos.Conclui-se que o clareamento profissional provoca uma resposta inflamatória mais intensa e um maior dano pulpar quando comparado ao clareamento caseiro em molares.

O presente estudo teve por objetivo avaliar a eficiência da extração de lignina de cavacos da madeira de Eucalyptus grandis x Eucalyptus urophylla a partir de pré-tratamentos com xilenosulfonato de sódio (SXS), bem como determinar as condições ótimas destes, com intuito de aumentar a eficiência dos processos de polpação e branqueamento, através da redução da necessidade de reagentes. Primeiramente procedeu-se a caracterização física, química e morfológica da madeira. Na sequência os cavacos foram submetidos à pré-tratamentos a partir da combinação dos fatores: tempo (1, 3, 6, 9 e 12 h), concentração de SXS (0, 10, 20 e 30 %) e temperatura (110, 120 e 130 ºC). Após os pré-tratamentos determinaram-se os parâmetros de rendimento e teor de lignina remanescente nos cavacos, a partir dos quais obtiveram-se os pontos ótimos referentes a cada fator, para o máximo rendimento e extração de lignina. De posse dos pontos ótimos para cada parâmetro, esses foram replicados para obtenção de cavacos pré-tratados que foram utilizados nas curvas de cozimento pelo processo kraft de polpação com e sem a aplicação de antraquinona e comparados a cavacos normais. A partir das curvas de cozimento determinou-se a carga alcalina necessária para obtenção de polpa com número kappa 15 ± 0,5. Na sequência as polpas obtidas foram branqueadas, refinadas e avaliadas quanto as suas características físico-mecânicas. Os resultados da caracterização física, química e morfológica demonstraram que a madeira em questão apresenta valores consoantes com os citados na literatura. Os pré-tratamentos com SXS foram eficientes na extração da lignina. O pré-tratamento que proporcionou o maior rendimento foi 1 h, 0 %, 117,5 ºC; e a maior extração de lignina foi com 12 h, 30 %, 130 ºC, removendo 39,60 % desta. Com base nas curvas de cozimento observou-se que os valores de rendimento da polpa obtida a partir dos cavacos pré-tratados com SXS são muito inferiores aos cavacos normais, porém em contrapartida apresentaram alto grau de deslignificação, sendo possível obter polpa de mesmo número kappa com cargas de álcali ativo consideravelmente menores que para cavacos normais, desta forma aumentando a eficiência do processo de polpação. Para polpa com mesmo número kappa (15 ± 0,5) a carga alcalina necessária foi 34,8 e 37,6 % menor para os cavacos pré-tratados com SXS, sem e com antraquinona, respectivamente, quando comparado com os cavacos normais. As polpas obtidas dos cavacos pré-tratados apresentaram maior eficiência na pré-deslignificação com oxigênio e maior branqueabilidade. Em relação aos testes físicos e mecânicos, as polpas obtidas com o pré-tratamento com SXS apresentaram bom desempenho nas propriedades físicas, porém nas mecânicas foram inferiores. De maneira geral, o pré-tratamento dos cavacos da madeira de E. grandis x E. urophylla com SXS foi eficaz na extração de lignina, reduzindo a necessidade de reagentes químicos nas etapas de polpação e branqueamento, aumentando a eficiência de ambas. Assim recomenda-se o pré-tratamento de 12 h, 30 % SXS, 130 ºC para remoção da maior quantidade de lignina dos cavacos, de maneira a otimizar o processo de polpação kraft, reduzindo a necessidade de reagentes. / The present study aimed evaluate the efficiency of lignin extraction from wood chips of Eucalyptus grandis x Eucalyptus urophylla from pretreatments with sodium xylenesulphonate (SXS), and determine the optimum conditions of these, in order to increase the efficiency of the pulping and bleaching processes, by reducing the necessity of reagents. First of all proceeded the physical, chemical and morphological characterization of wood. After the chips were submitted to pretreatments from the combination of factors: time (1, 3, 6, 9 and 12 h), concentration of SXS (0, 10, 20 and 30 %) and temperature (110, 120, and 130 °C). After the pretreatments were determined the yield and the level of remaining lignin in the chips, from which was obtained the optimal points for each factor for maximum yield and lignin extraction. With the optimum points for each parameter, these were replicated to obtain pretreated wood chips that were used in the cooking curves from kraft pulping process, and compared with normal chips, both with and without anthraquinone. From the cooking curves were determined the alkaline charge required to obtain pulp with a kappa number of 15 ± 0.5, which was reproduced for evaluation the characteristics of the pulp obtained from the wood chips with and without pretreatment. Later these pulps were bleached, refined and evaluated for their physical and mechanical characteristics. The results of physical, chemical and morphological characterization showed that the wood in question has consonant with the values reported in the literature. The pretreatments with SXS were efficient to lignin extracting. The pretreatment that provided the highest yield was 1 h, 0 %, 117.5 °C; and the highest extraction of lignin was 12 h, 30 %, 130 °C, removing 39,60 % thereof. Based on the cooking curves was observed that the values obtained for yield of pulp from pretreated wood chips with SXS were much lower than normal chips, but in other hand showed a high delignification degree, being possible obtain pulp with the same kappa number with active alkali charges considerably smaller than for normal chips, thereby increasing the efficiency of the pulping process. For pulp with the same kappa number (15 ± 0.5) the alkaline charge required was 34.8 and 37.6 % lower for pretreated wood chips with SXS, without and with anthraquinone, respectively, when compared with normal chips. The pulps obtained from the pretreated wood chips showed higher efficiency in the pre-delignification with oxygen and higher bleachability. For physical and mechanical tests, the pulps obtained by pretreatment with SXS presented good performance in physical properties, but were lower in mechanical tests. In general way, the pretreatment of the wood chips of E. grandis x E. urophylla with SXS was efficient in the lignin extraction, reducing the necessity of the chemicals in pulping and bleaching stages, increasing the efficiency of both. Thus it is recommended pretreatment of 12 h, 30 % SXS 130 °C to remove as much of the lignin from the chips, in order to optimize the kraft pulping process, reducing the need for reagents.

Le verbe dar est une unité lexicale particulièrement riche en nuances significatives. Parmi les études qui ont abordé cette unité, certaines font l'hypothèse d'une désémantisation lors de la 'grammaticalisation' du verbe. Ce processus serait illustré notamment par l'existence du marqueur discursif dale ainsi que par les emplois de dar en tant que 'support' dans des constructions verbo-nominales plus ou moins lexicalisées ou dans périphrases verbales du type dar un golpe, dar que hablar. L'hypothèse envisagée dans cette étude – menée dans le cadre théorique de la linguistique du signifiant, qui prône l'unicité du signe linguistique – est que le verbe dar exprime une notion d'existence sous-jacente à tous ses emplois discursifs. Le signifié de langue de dar exprimerait l'accès à l'existence d'une entité b, pour le bénéficiaire c d'une opération conduite par une entité a. Cette notion d'existence serait présente dans toutes les occurrences d'un lexème qui n'apparaît jamais vidé – ne serait-ce que partiellement – de son contenu lexical. Afin de valider cette hypothèse, les différentes capacités référentielles du verbe dar seront analysées à travers un corpus de l'espagnol péninsulaire et de l'Amérique latine. / The Spanish verb dar is a lexical item particularly rich in nuances of meaning. Some of its senses have been studied under the « semantic bleaching » hypothesis consequent upon the « grammaticalization » of the verb. This process would reveal mainly in the discourse marker dale and in the use of dar as a « support verb » in nominal predicates like dar un golpe, dar un paseo, dar una mano de pintura, etc. According to the theoretical framework for this research, which accounts for the distinction between language and discourse as well as the unicity of the linguistic sign, an existential notion underlies every discourse realization of this verb. The notion conveyed by the signified of dar is that an entity B gains access to existence in the sphere of an entity C as a result of the action of an entity A. Hence, this existential meaning appears in every use of a lexeme whose semantic content is never affected.

Within the field of second language acquisition of phonology, the role of immersion experiences on language learners' pronunciation has recently become a topic of greater interest. While students of a foreign language with study abroad experience (one to six months) have shown relatively little progress in pronunciation gains, language learners group with extended immersion experience—approximately 24 months abroad—have demonstrated more native-like pronunciation. This study compares the pronunciation of L2 Spanish /u/ among native English speakers enrolled in the same third-year Spanish course who belong to two different groups based on the context of their previous language learning: extended immersion in a Spanish-speaking country or traditional classroom instruction. The effects of syllabic stress and speech task type on the pronunciation of these two groups are also examined. Acoustic data from participants' speech is used to conduct statistical analyses. Words and phrases are subject over time to a process called grammaticalization, especially those that are used frequently. This process causes a gradual shift from use as lexical items to use as grammatical devices. Semantic bleaching also occurs, which means that the earlier or original lexical content of a word or phrase is partially or completely lost. Verbs expressing the idea of possession are particularly susceptible to this type of change. The Spanish verb tener ('to have'), while still retaining its lexical content, has come to be used in constructions that do not represent the explicit idea of possession—they incorporate a bleached usage of the word. This alteration is evident in four construction types examined in this paper. These constructions all have three essential elements: a "possessor" argument, a "possessed" argument, and a third modifying component. The analyses of these constructions include templates that describe both their semantic content and their syntactic structure.

The iconic pillar coral, Dendrogyra cylindrus, is one of five Caribbean species listed in 2014 under the US Federal Endangered Species Act because of its extreme low abundance and continued decline in US waters. Until recently, little was known about the demographics or genetic diversity of Florida’s D. cylindrus population. This study represents the first time two holobiont partners (coral animal and associated photosynthetic algal endosymbionts) have been closely examined, spatially and temporally, in this little-studied species. The aim was to explore the influences of coral animal genotypes, mutualistic photosynthetic algal strains, and hyperthermal stress on bleaching and disease processes, resistance, and recovery through two consecutive hyperthermal events on the Florida Reef Tract (FRT) in 2014 and 2015. Through geographically stratified, triannual assessments and tissue sampling of D. cylindrus colonies across three regions of the FRT from April 2014 to April 2016, I compared genotypic identities of the coral animal to bleaching and disease status and recovery. Additionally, I characterized the algal endosymbionts (Symbiodiniaceae family) in D. cylindrus between regions of the FRT using Illumina amplicon sequencing of the partial chloroplast 23S rDNA Domain V gene and correlated them to differential responses during bleaching and recovery. Finally, I examined the effects of hyperthermal stress on disease prevalence and changes in disease susceptibility in D. cylindrus throughout two consecutive hyperthermal events in 2014 and 2015. Genotypic differences in D. cylindrus were associated with full or partial bleaching and/or disease resistance associated with some genets. Additionally, this study characterized unexpected diversity in the Symbiodiniaceae community within D. cylindrus and a site-specific, species-level switch in endosymbionts associated with acquired bleaching resistance during the 2015 hyperthermal event. Finally, this study demonstrated that two consecutive hyperthermal events were associated with an increase in prevalence of white plague in D. cylindrus and contributed to its susceptibility to black band disease, documented for the first time on the FRT. Through understanding the response of the D. cylindrus holobiont partners to biotic and abiotic stressors, such as hyperthermal bleaching and associated diseases, we gained valuable insights into how this threatened species may respond to a changing climate.

<p>An essential ingredient in the generation of environmentally compatible pulp bleaching chemicals is sodium chlorate. Chlorate is produced in electrochemical cells, where the electrodes are the key components. In Sweden the so-called DSA !R electrodes with catalytic coatings have been produced for more than 35 years. The production of chlorate uses a large amount of electric energy, and a decrease of just five percent of this consumption would, globally, decrease the consumption of electrical energy corresponding to half a nuclear power reactor. The aim of this project is to improve the electrode design on the nanoscale to decrease the energy consumption. The success of the DSA!R depends on the large catalytic area of the coating, however, little is known about the actual structure at the nanometer level. To increase the understanding of the nanostructure of these coatings, we used a number of methods, including atomic force microscopy, transmission electron microscopy, X-ray diffraction, porosimetry, and voltammetric charge. We found that the entire coating is built up of loosely packed rutile mono-crystalline 20 − 30 nm sized grains. The small grain sizes give a the large area, and consequently, lower cell-voltage and reduced energy consumption. A method to control the grain size would thus be a way to control the electrode efficiency. To alter the catalytically active area, we made changes in the coating process parameters. We found a dependency of the crystal-grain sizes on the choice of ruthenium precursor and processing temperature. The use of ruthenium nitrosyl nitrate resulted in smaller grains than ruthenium chloride and lowering the temperature tended to favour smaller grains. A more radical way would be to create a totally different type of electrode, manufactured in another way than using the 1965 DSA !R recipe. Such new types of electrodes based on, for example, nanowires or nanoimprint lithography, are discussed as future directions.</p>

Understanding coral disease dynamics within the heterogeneous populations in which they act is critical for predicting how the structure of reefs may change as a result of enzootic or epizootic levels of these important sources of mortality. This work focused on combining field studies and the development and testing of a spatially-explicit, individual-based epizootiological computer model with the aim of gaining a greater understanding of the dynamics and impact of white plague, a significant source of mortality on reef-building corals in the Caribbean region. Field studies focused on the incidence and distribution of all sources of coral mortality, including suspect white plague in situ, at two locations; the Florida Keys (United States of America) and Little Cayman Island (Cayman Islands, British West Indies). Results indicated that in both regions disease was the most significant source of mortality during the monitoring time periods, and that suspect white plague type II in Cayman is likely contributing to major structural changes. In Florida, observations made during a mass bleaching event indicated that a significant relationship exists between bleaching severity and disease incidence, and that mortality during the event was largely the result of disease and not bleaching. The simulation model was developed using a long-term data set from Little Cayman, and results of calibration indicated that suspect white plague type II on these reefs is transmissible between colonies within a limited field and require a yearly input from an outside source, and that host susceptibility to infection is low and likely not variable among species. Parameters describing the distribution and composition of the coral population were varied, and results indicated a significant effect of colony density, aggregation, and mean size on the impact of disease. Scenario testing of various disease management strategies indicated that should local prevention measures be developed in the future, it is they, and not treatment, that will likely be the most effective in limiting the impact of disease.

During pulp and papermaking process a huge amount of water is used. The wastewater contains a large amount of pollutants and has to be treated before it reaches the recipient. In March 2004 a new bleaching plant was started up at SCA Graphic Sundsvall AB, Ortviken’s paper mill using peroxide. The production of bleached thermo mechanical pulp and thus the load to the wastewater plant increased. During bleaching substances dissolve from the pulp and the amount of COD in the wastewater increase. To keep the efficiency of chemical and biological oxygen demand (COD, BOD) removal, the aerated lagoon is supplied by liquid oxygen. In November the same year a new pre-step including a pre-aeration, carrier and selector step was added to the existing wastewater plant. The COD-loading to the lagoon decreased and the supply of liquid oxygen was reduced. This master thesis has been carried out at SCA Graphic Research AB, Sundsvall. The aim was to chemically characterize the wastewater with focus on the composition of carbohydrates, lignin and extractives and its influence on the biodegradability. Measurements have been carried out on total samples, suspended solids, colloidal and dissolved substances using GF/A and ultra filtration. Measurements were performed on process water from the bleaching plant and on water during the wastewater treatment process. The results show that the chemical composition of dissolved substances has a larger impact on the biodegradability than the total amount of COD. A large amount of lignin will make the wastewater harder to degrade. Suspended solids have lower biodegradability compared to the dissolved fraction. Analyzes of suspended material from the bleaching plant show a relative composition of around 41 % lignin. Analyzes done before on the dissolved fraction show a composition of 29 %. It seems that a larger amount of lignin is represented in suspended solids compared to the dissolved fraction. This can explain the low biodegradability, combined with the theory that the suspended solids are less accessible for the microorganisms. To reduce the outgoing COD the incoming flow of dissolved lignin and suspended solids to the active sludge plant has to decrease. COD in the outgoing wastewater to the recipient consists of around 90 % lignin. Extractives as saturated fatty acids, palmitic and stearic acid plus lignans (which is interpreted as a byproduct from lignin degradation) do not degrade remarkable during wastewater treatment. Flocculation of COD is one way to reduce the discharge to the recipient. Addition of 2,6 g/l PAX-18 (a high charged aluminum complex) to the wastewater from the bleaching plant gives a reduction of 40 % COD and 50 % lignin in laboratory scale and it is recommended to study further. Time related studies of BOD show that the microorganisms need five days to degrade organic material and the hydraulic retention time in the aerated lagoon has to be guaranteed. / Vid massa- och pappersframställning åtgår stora mängder vatten. Det processberörda avloppsvattnet innehåller mycket föroreningar varför det måste renas innan det släpps ut till recipienten. I mars 2004 startades ett nytt väteperoxidblekeri vid SCA Graphic Sundsvall AB, Ortvikens pappersbruk varvid produktionen av blekt termomekanisk massa ökade och den biologiska reningen belastades hårdare. Blekning löser ut vedämnen från massan och bidrar således till ökad mängd syreförbrukande ämnen i avloppet. För att upprätthålla reduktionen av syreförbrukande ämnen (COD, BOD) tillförs ren syrgas till den luftade dammen. I november samma år utökades den externa reningsanläggningen med ett biologiskt försteg, en s.k. multibioanläggning bestående av ett frisimmarsteg, ett bärarsteg samt ett selektorsteg. COD-belastningen in till den luftade dammen minskade och tillförseln av ren syrgas kunde reduceras. Examensarbetet har utförts vid SCA Graphic Research AB, Sundsvall med syftet att kemiskt karaktärisera avloppsvattnets sammansättning av kolhydrater, lignin och extraktivämnen och dess inverkan på vattnets grad av biologisk nedbrytbarhet. Analyser har gjorts på totalprov, suspenderande ämnen samt kolloidalt och löst material via fraktionering med hjälp av GF/A- och ultrafiltrering. Analyser gjordes dels på processvatten från blekerierna och dels på avloppsvatten under reningsprocessen. Resultaten visar att den kemiska sammansättningen hos löst material har större inverkan på avloppsvattnets grad av nedbrytbarhet än den absoluta halten av syreförbrukande ämnen. En hög andel lignin ger ett mer svårnedbrytbart vatten. Suspenderat material är vidare mer svårnedbrytbart än de lösta fraktionerna. Analys av suspenderande substans hos blekpressat visar att andelen lignin är omkring 41 % medan arkiverade analysresultat på den lösta fasen visar ett innehåll på omkring 29 %. Det tyder alltså på en betydligt högre andel lignin i den partikulära fasen jämfört med den lösta, vilket i kombination med att materialet inte är lika lättillgängligt för mikroorganismerna kan förklara den låga bionedbrytbarheten. Om COD-utsläppet ska minskas bör inkommande flöde av löst lignin och suspenderande substans till den biologiska reningen reduceras. COD-halten i utgående avloppsvatten till recipienten utgörs av omkring 90 % lignin. De extraktivämnen som inte bryts ned är mättade fettsyror, exempelvis palmitin- och stearinsyra samt lignan, vilket antas bildas som restprodukt vid degradering av lignin. Flockning av syreförbrukande ämnen är ett sätt att gå till väga för att minska utsläppet av dessa till recipienten. Genom tillsats av 2,6 g/l PAX-18 (ett högladdat aluminiumkomplex) till blekeriavloppet kunde 40 % COD och 50 % lignin reduceras. Flockningsförsöket är gjort i laboratorieskala vid rumstemperatur och ytterligare utvärdering rekommenderas. Tidsstudier av BOD visar att mikroorganismerna behöver fem dagars uppehållstid för att hinna bryta ned organiskt material i avloppsvattnet, varför omloppstiden i den luftade lagunen inte bör understiga denna tidsrymd.

Over the past 10 years, growing concerns over the modification of fibers have led researchers to focus on enriching the carboxyl group content of fibers by chemical oxidation and topochemical grafting. The current series of experiments continues this line of research by investigating the carboxyl group content of fibers during kraft pulping, alkaline peroxide bleaching, and 2,2,6,6-tetrametyl-1-piperidinyloxy radical (TEMPO)-KBr-NaClO oxidation system. The first experiment characterizes changes in the carboxyl group content of fibers for two sets of kraft pulps: 1) conventional laboratory cooked loblolly pine kraft pulps, and 2) conventional pulping (CK) versus Lo-Solids pulping (LS) pulps. The results indicate that effective alkali (EA), temperature, and H-factor are the primary factors controlling fiber charge during kraft pulping. Another set of kraft pulps distinguished by conventional pulping and Lo-Solids pulping were investigated to determine the effect of H-factor and pulping protocol on fiber charge. The second experiment examines the influence of alkaline peroxide treatment on elementally chlorine-free (ECF) bleached softwood kraft pulp. The effect of increased fiber charge on refining, cationic starch adsorption, and hornification was examined. The final experiment investigates the effect of TEMPO-mediated oxidation of an ECF bleached softwood kraft pulp on carboxyl group content, carbonyl group contents, degree of polymerization, and water retention value of fibers. The results show that TEMPO-mediated oxidation is useful in enriching the carboxyl and carbonyl groups to fibers, as well as enhancing the property of water adsorption of fibers. These findings suggest that: (1) kraft pulping process can be modified to obtain the target carboxyl group content, (2) terminal peroxide bleaching provides higher fiber charge which can save energy and chemical charge of subsequent refining and wet-end processes, respectively, as well as reduce hornification during drying, (3) TEMPO-mediated oxidation of fibers is capable of improving the properties of fibers, including fiber charge and water adsorption, and enhancing final paper strength.

Coral reefs are in global decline, with seaweeds increasing as corals decrease. Though seaweeds have been shown to inhibit coral growth, recruitment, and survivorship, the mechanism of these interactions is poorly known. Here we use field experiments to show that contact with four common seaweeds induces bleaching on natural colonies of Porites rus. Controls in contact with inert, plastic mimics of seaweeds did not bleach, suggesting treatment effects resulted from allelopathy rather than shading, abrasion, or physical contact. Bioassay-guided fractionation of the hydrophobic extract from the red alga Phacelocarpus neurymenioides revealed a previously characterized antibacterial metabolite, Neurymenolide A, as the main allelopathic agent. For allelopathy of lipid soluble metabolites to be effective, the metabolites would need to be deployed on algal surfaces where they could transfer to corals on contact. We used desorption electrospray ionization mass spectrometry (DESI-MS) to visualize and quantify Neurymenolide A on the surface of P. neurymenioides and found the metabolite on all surfaces analyzed. The highest concentrations of Neurymenolide A were on basal portions of blades where the plant is most likely to contact other benthic competitors.