Universidade Estadual de Campinas (UNICAMP)

The cold finger apparatus is widely employed for practical screening of wax deposition and inhibitor performance, however, it is typically restricted to macroscopic metrics such as deposit mass or thickness. In this work, the cold finger was coupled with high-temperature gas chromatography (HTGC) and differential scanning calorimetry (DSC) to investigate wax deposition from a mechanistic perspective using model waxy fluids, systematically exploring two experimental variables scarcely addressed in the literature: the total wax concentration and the macrocrystalline/microcrystalline wax ratio in the stock solution. The results show that increasing wax concentration enhances the deposition driving force and increases the paraffin content in the deposits. Deposits formed from diluted solutions are proportionally enriched in heavier paraffins, whereas those formed from concentrated solutions more closely reflect the stock composition, indicating differences in solubility-driven selectivity and deposition kinetics. DSC analysis revealed that highly polydisperse systems exhibit higher WATs due to multiple independent crystalline populations and an increased number of nucleation sites, whereas increasing microcrystalline content leads to lower crystallization enthalpies, indicating smaller and less ordered crystalline domains. Cocrystallization of distinct wax populations significantly alters the physico-chemical behavior of the deposits. Overall, wax concentration is primarily related to the deposition driving force and extension of wax deposition, while wax polydispersity controls the crystalline morphology and nucleation behavior. These findings demonstrate that coupling cold finger experiments with HTGC and DSC can provide an expanded physico-chemical framework for interpreting wax deposition, which can support the rational development of flow assurance strategies and selection of chemical inhibitors. • The cold finger apparatus was coupled with HTGC and DSC to provide physico-chemical insight into wax deposition. • Wax concentration relates with deposition driving force, affecting deposition extent and solubility-driven selectivity. • Wax polydispersity influences nucleation behavior, the number of crystalline populations and deposit crystalline morphology. • Model waxy fluids provide frameworks for future studies involving other crude oil components or chemical additives.

The expansion of land use in Brazil has caused biodiversity loss and increased human interaction with parasites and pathogens previously restricted to natural ecosystems. Chigger mites are ectoparasites during the larval stage and can cause skin reactions or transmit pathogens to their hosts, including humans. This study aimed to evaluate the diversity of chiggers collected from all five Brazilian biogeographical regions, along with pathogen surveillance. Specimens were subjected to both morphological taxonomy and endogenous control, followed by PCR assays targeting pathogens of the genera Borrelia, Orientia, and Rickettsia. The analyses revealed a high species richness, including two novel records in Brazil: the genus Boshkerria and the species Quadraseta antillarum. Additionally, the genus Quadraseta tested positive for Rickettsia sp., while tests for the other agents were negative. This is the first report of a Rickettsia sp. agent detected in a Quadraseta nymph.

Epidemiological studies describe a positive correlation between sugar consumption during pregnancy and the risk for atopic respiratory diseases in the progeny. In the present study we developed an experimental model to test whether the offspring born to and/or breastfed by mice exposed to liquid fructose would manifest changes in the allergic airway disease induced by sensitization and challenge with ovalbumin (OVA). Male mice born to mothers consuming fructose during pregnancy and/or lactation exhibited exacerbated infiltration of eosinophils and lymphocytes in the bronchoalveolar lavage (BAL) after challenge with OVA. Such changes were not detected in the female progeny. On the other hand, the OVA-challenged female progeny born to and breastfed by mothers consuming fructose exhibited higher concentrations of IL-4, IL-5 and TGF-β1 in the BAL and IgE in serum. Additional characteristics that were specifically programmed in the male progeny born to mothers exposed to fructose during pregnancy and lactation comprised increased BAL levels of IL-10, eosinophil infiltration in the lung parenchyma, lung collagen deposition and goblet cell numbers and ccl11, muc5b and receptor for advanced glycation endproducts expression in the lung. Altogether, our experimental approach reveals a previously undescribed causal relationship between maternal fructose consumption and changes in the allergic response in the offspring exposed to the OVA model. Such changes are sex-specific and while the female progeny exhibits higher IL-4, IL-5, TGF-β1 and IgE levels upon challenge with OVA, only the male offspring manifested exacerbated hallmarks of severe disease, including cellular infiltration, goblet cell hyperplasia, and collagen deposition.