Dissolution of silicate minerals and nutrient availability for corn grown successively

O objetivo deste trabalho foi avaliar a disponibilidade de nutrientes para milho (Zea mays) cultivado sucessivamente em amostras das rochas puras e moídas biotita xisto e biotita sienito. Os pós das rochas foram submetidos à caracterização química, física e mineralógica, e a disponibilidade dos elementos liberados para as plantas foi determinada. Os materiais de planta e rocha foram avaliados no final de sete ciclos sucessivos de cultivo. A biotita xisto e a biotita sienito forneceram nutrientes – como K, Ca, Mg, Fe e Mn – para as plantas de milho. Os nutrientes acumulados no tecido das plantas vieram de minerais contendo Fe e Mn oxidáveis em sua estrutura, tais como biotita, chlorita e clinopiroxênio. A dissolução congruente de algumas partículas finas dos minerais, solubiliza elementos que podem, então, ser disponibilizados para as plantas.The objective of this work was to evaluate the nutrient availability for corn (Zea mays) grown successively in pure and ground biotite schist and biotite syenite rock samples. The rock powders were subjected to chemical, physical, and mineralogical characterization, and the availability of the elements released to the plants was determined. Plant and rock materials were evaluated at the end of seven successive growth cycles. Biotite schist and biotite syenite provided nutrients – as K, Ca, Mg, Fe, and Mn – to the corn plants. The nutrients accumulated in plant tissues came mostly from minerals containing oxidizable Fe and Mn in their structure, such as biotite, chlorite, and clinopyroxene. The congruent dissolution of some of the fine particles of these minerals, solubilize elements, which may, then, be available to the plants

Produção De Nanocompósitos De Termoplásticos Ou ElastÈmeros Com Argilas Intercaladas Ou Esfoliadas, A Partir De Latéxes

A presente invenção se refere à preparação de nanocompósitos formados por materiais lamelares intercalados ou esfoliados, obtidos pela dispersão de lamelas de um filossilicato em termoplásticos como o poliestireno homo ou co-polimérico, acrílicos, PVA, borracha natural, SBR, borracha nitrílica e outros polímeros obtidos na forma de látex por polimerização em emulsão ou dispersão, sendo que a dispersão é feita por métodos de mecânica físico-química especificamente pela ação de cisalhamento da mistura do filossilicato com um látex. O filossilicato utilizado nesta invenção é uma argila natural ou sintética ou outro tipo de composto lamelar, dispensando qualquer processo anterior de intumescimento dos tipos descritos em numerosas patentes e a artigos da literatura. A presente invenção se refere ainda aos artigos produzidos com os referidos nanocompósitos.BR0301193 (C1); BR0301193 (A)C08K3/34C08L7/02C08L7/02C08K3/34BR20030301193C08K3/34C08L7/02C08L7/02C08K3/3

Osmoprotectants play a major role in the Portulaca oleracea resistance to high levels of salinity stress—insights from a metabolomics and proteomics integrated approach

IntroductionPurslane (Portulaca oleracea L.) is a non-conventional food plant used extensively in folk medicine and classified as a multipurpose plant species, serving as a source of features of direct importance to the agricultural and agri-industrial sectors. This species is considered a suitable model to study the mechanisms behind resistance to several abiotic stresses including salinity. The recently achieved technological developments in high-throughput biology opened a new window of opportunity to gain additional insights on purslane resistance to salinity stress—a complex, multigenic, and still not well-understood trait. Only a few reports on single-omics analysis (SOA) of purslane are available, and only one multi-omics integration (MOI) analysis exists so far integrating distinct omics platforms (transcriptomics and metabolomics) to characterize the response of purslane plants to salinity stress.MethodsThe present study is a second step in building a robust database on the morpho-physiological and molecular responses purslane to salinity stress and its subsequent use in attempting to decode the genetics behind its resistance to this abiotic stress. Here, the characterization of the morpho-physiological responses of adult purslane plants to salinity stress and a metabolomics and proteomics integrative approach to study the changes at the molecular level in their leaves and roots is presented.Results and discussionAdult plants of the B1 purslane accession lost approximately 50% of the fresh and dry weight (from shoots and roots) whensubmitted to very high salinity stress (2.0 g of NaCl/100 g of the substrate). The resistance to very high levels of salinity stress increases as the purslane plant matures, and most of the absorbed sodium remains in the roots, with only a part (~12%) reaching the shoots. Crystal-like structures, constituted mainly by Na+, Cl−, and K+, were found in the leaf veins and intercellular space near the stoma, indicating that this species has a mechanism of salt exclusion operating on the leaves, which has its role in salt tolerance. The MOI approach showed that 41 metabolites were statistically significant on the leaves and 65 metabolites on the roots of adult purslane plants. The combination of the mummichog algorithm and metabolomics database comparison revealed that the glycine, serine, and threonine, amino sugar and nucleotide sugar, and glycolysis/gluconeogenesis pathways were the most significantly enriched pathways when considering the total number of occurrences in the leaves (with 14, 13, and 13, respectively) and roots (all with eight) of adult plants; and that purslane plants employ the adaptive mechanism of osmoprotection to mitigate the negative effect of very high levels of salinity stress; and that this mechanism is prevalent in the leaves. The multi-omics database built by our group underwent a screen for salt-responsive genes, which are now under further characterization for their potential to promote resistance to salinity stress when heterologously overexpressed in salt-sensitive plants

Natural rubber-clay nanocomposites : preparation from latex

Orientador: Fernando GalembeckDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de QuimicaMestradoFísico-QuímicaMestre em Químic

Microscopical study of nanometric particles adhesion

Orientador: Fernando GalembeckTese (doutorado) - Universidade Estadual de Campinas, Instituto de QuimicaResumo: A adesão de fases nanométricas é um tópico de crescente interesse científico por ter implicações na fabricação e nas propriedades de novos materiais nanoestruturados. A hipótese explorada nesse estudo é: fases imiscíveis mas molháveis pela água podem aderir desde que sejam misturadas e secas a partir de dispersões aquosas e possuam cargas em sua superfície. Esta hipótese é detalhada no seguinte mecanismo: primeiro, durante o processo de secagem, as partículas são aproximadas até o contato por forças de adesão capilar. Em segundo lugar, no sólido seco, as partículas, mesmo que tenham mesma carga, são atraídas pelos cátions provenientes do soro, que formam pontes iônicas entre as superfícies e originam a adesão eletrostática. Para verificar esta hipótese, pares de diversos tipos de nanopartículas foram misturados em meio aquoso e deixados secar, sendo o resultado da secagem analisado por microscopia eletrônica e de sonda. A microscopia eletrônica de transmissão por energia filtrada (EFTEM) foi explorada intensamente, utilizando um novo protocolo experimental que possibilita a análise de partículas e agregados espessos (> 500 nm). Em todos os casos observados, partículas das diferentes fases permanecem em contato após a secagem, revelando que as forças capilares são eficazes para unir nanopartículas molháveis. No caso de misturas de montmorilonita cálcica e látex estirenoacrílico foi observado que os íons Ca estão localizados em domínios onde a argila e o látex estão superpostos, evidenciando a formação de pontes iônicas. A contribuição da energia eletrostática para a adesão de interfaces carregadas foi calculada utilizando um modelo formado por três superfícies paralelas, no qual uma superfície com cargas positivas está disposta entre duas superfícies que possuem cargas negativas. Os cálculos mostraram que em condições análogas às de uma interface formada por látex estireno-acrílico e montmorilonita, a contribuição eletrostática na interface pode alcançar valores de -200 kJ.mol. Esses valores verificam resultados experimentais obtidos em ensaios de tração. O modelo de adesão eletrostática foi empregado no preparo de materiais nanocompósitos de PET e argila, obtendo-se materiais com tensão na ruptura superior à do polímero puro. Uma outra parte da tese descreve a síntese de nanomotores autoimpulsionados. Estes são dubletos formados por uma partícula de sílica aderida a uma partícula de platina. A superfície da platina catalisa a decomposição do peróxido de hidrogênio em solução aquosa criando gradientes de tensão superficial que impelem os dubletos, produzindo movimentos não-BrownianosAbstract: The adhesion of nanometric phases is a topic of increasing scientific interest due to its importance for the production and properties of new nanostructured materials. This study explores the following hypothesis: immiscible and wettable particles carrying charges with same signal can adhere provided that they are mixed in aqueous dispersion and dried out. This hypothesis is detailed in the following mechanism: first, during the drying process the particles are attracted and placed in close contact due to the capillary adhesion forces. Second, the evenly charged particles in the resulting dry solid are counterbalanced by counter-ions from the serum, forming ionic bridges between the surfaces, that account for electrostatic adhesion. To verify this hypothesis, pairs of many nanoparticles types were mixed in aqueous medium and dried out. The resulting samples were analyzed by electron and probe microscopy. The energy filtered transmission electron microscopy (EFTEM) was extensively explored thanks to a new experimental protocol that allows the analyses of thick particles and aggregates (> 500 nm). In every case, the different phases remain in contact with each other after drying, showing that electrostatic forces are able to unite evenly charged particles. In the case of calcium montmorillonite and styrene-acrylic latex, Ca ions are located in domains in which the clay and the latex are superimposed, evidencing ionic bridge formation. The contribution of the electrostatic energy to the adhesion of charged interfaces was calculated using a model of three parallel surfaces, in which a positively charged surface is in between two negatively charged surfaces. Calculations have shown that in conditions analogous to the styrene-acrylic latex and montmorillonite interface, the electrostatic contribution in the interface can reach values as high as -200 kJ.mol and these results are verified using experimental data from mechanical testing. The electrostatic adhesion model was used to prepare PET and clay nanocomposite materials, obtaining materials with tensile strength higher than the pristine polymer. The final section of the thesis describes self-propelled nanomotors synthesis. These are doublets made of a silica particle adhered to a platinum particle. Platinum surface catalyses the hydrogen peroxide decomposition in aqueous solution creating a surface tension gradient that propels the dimers, producing non-Brownian motionDoutoradoFísico-QuímicaDoutor em Ciência

Tailoring Acrylated Soybean Oil-Containing Terpolymers through Emulsion Polymerization

This work focuses on the synthesis of terpolymers using methyl methacrylate (MMA) and vinyl pivalate (VPi), along with the incorporation of methacrylate acid (MA) and acrylated fatty acids (AFA) derived from commercial soybean oil. Emulsion polymerizations were carried out using different monomeric species, along with different initiator concentrations ranging from 0.5 g∙L−1 to 2.2 g∙L−1. The thermal properties of the terpolymers were improved when acrylated fatty acid was incorporated into the polymer chains, expressing glass transition temperatures (Tg) ranging from 70 °C to 90 °C and degradation temperatures in the interval between 350 °C and 450 °C for acrylated fatty acid concentrations ranging from 5 wt% to 10 wt%. Furthermore, a change was noted in the molar mass distributions as a result of acrylated fatty oil present in the polymers. The materials with 5 and 10 wt% of acrylated fatty oil presented mass-average molar masses of 225 kg∙mol−1 and 181 kg∙mol−1, respectively. As the results in this work suggest, the molar masses of the formed polymers are significantly altered by the presence of modified fatty acids

Nanocompósitos Poliméricos, Processo De Preparo E Uso Dos Mesmos

NANOCOMPÔSITOS POLIMÉRICOS, PROCESSO DE PREPARO E USO DOS MESMOS. A presente invenção proporciona nanocompósitos de polímeros que compreendem uma partícula em escala nanométrica e um agente tensoativo. O processo de obtenção destes nanocompósitos é realizado em meio aquoso, na presença de um polímero, um tensoativo e uma nanopartícula e uma etapa posterior de secagem e fusão da mistura formada. O nanocompósito da presente invenção apresenta maior dureza e tenacidade e pode ser utilizado em diversos materiais.BRPI0802693 (A2)C08K3/00C08K9/00BR2008PI02693C08K3/00C08K9/0