Patricio Rodrigo Montecinos Muñoz.

High Hg levels in Amazonian aquatic media indicate heavy metal (HM) pollution and stimulate this biosorption research. Bacterial biosorption is first and strongly controlled by morphological parameters such as the (S#8260;V) ratio. Via TOF-SANS we monitored the morphological changes of Klebsiella pneumoniae (KP) driven by Hg+SiO2NPs inputs over time, from the bacterial wall up to their minimal radius (~150 nm). To access larger sizes than experiment 2024196 (KP length ~ 4 um), we propose time-resolved a TOF-SESANS monitoring of structural changes in KP driven by Hg+SiO2NPs inputs over time (8 and 16 ppm Hg). We hypothesise that KP can initially encapsulate Hg increasing their S/V ratio and enhancing their absorption capacity. SESANS is critical as it provides access to measure KPs size time-variations of length, diameter, and S/V ratio. Samples will contain Hg-resistant non-virulent KP strains, and SiO2NPs, inside 100 D2O Hg-rich Naphosphate buffers, totalling 4 time-resolved TOF-SESANS measurements (Mix samples). Other 6 measurements on starting components at 100 D2O will quantify each component's effects on Mix samples. An alternated collection of data over 3 h/sample will replicate the same time-framework of TOF-SANS experiment. BioCOSHH RA got approved for KP strains of experiment 2024196. The importance of this proposal resides in understanding bacterial structure variations in response to chemical changes over time, aiming for future applications in bioremediation.

Scientific collaboration with ISIS Neutron and Muon Source -UK- to perform small angle neutron scattering measurements on liquid systems composed of non-pathogenic bacteria, silica nanoparticle and HgCl2.High Hg levels, up to 4 ppm, in Amazonian fish indicate significant heavy metal (HM) pollution and stimulateresearch on bacterial bioremediation of these media. Simultaneous nanoparticles' aggregation and HMbacterialuptake offer an unmatched test on how both phenomena can limit Hg-species' mobility. Sinceaggregation is a microstructural phenomenon dependent on time and pH, we propose contrast-matchingand time-resolved SANS experiments on the SiO2 nanoparticles (NPs)-HgCl2-HM resistant bacteriasystem. We hypothesise that silica's aggregation in the presence of HM-resistant bacteria can encapsulateHg, reducing its levels in the liquid phase. Measurements on 1 and 8 ppm Hg series will comprise ~60and 100 D2O liquid buffers, pH ~7, pressure and temperature ambient conditions, totaling 4 time-resolvedSANS experiments to probe the vector q range from ~0.004 to 0.3 Å^-1 at Larmor beamline. At pH~7,cationic Hg species predominate, raising our expectation to observe aggregates up to 157 nm. A ~60D2O buffer matches the SLD of SiO2-NPs, which could help observe HgCl2-bacteria interactions. At 100D2O, bacterial lipids display high squared contrast, providing the best conditions to probe silicabacteriainteractions. This proposal focuses on biosilica initial formation stages and could be important for thebioremediation of Amazonia media where Hg levels largely exceed the Brazilian law's threshold (0.5 Hgppm).SEE: doi:10.5286/ISIS.E.RB2420196

Much of what we know about the evolution of life on Earth comes from the analysis of chert and porcelanite carrying well-preserved organic molecules (OMs) and microfossils. This preservation has had little experimental explanation. In 2016, Aellon et al. (doi 10.1016/j.chemgeo.2016.05.034 0009-2541) suggested that fossilization, driven by the conversion of amorphous silica to quartz, could preserve microfossils and OMs during geological timescales. In this conversion, the SiO2-OMs aggregates undergo a reduction in permeability, preventing the mobility of the OMs. However, the current literature does not explain how the microstructure of SiO2 polymorphs and porosity can control this preservation. We have characterized chert and marine Cretaceous porcelanites in approaching this subject using (U)SAXS, WAXS, Raman, GC-MS, MALDI-TOF, XRD TGA and SEM-EDS.
Experiments at USP and the Advanced Photon Source synchrotron (USA) initially proved that our samples are composed of quartz-OMs agglomerates supporting a porosity of fractal geometry. Such organization has persisted since the Cretaceous protecting the OMs. In this proposal, a critical question is the role of silica microstructure for OMs preservation in cherts older than Cretaceous. We propose to apply the same analytical approach to these rocks. We pretend to apply Raman-AFM-TERS to probe the spatial distribution of OMs at the nanoscale in these cherts. Moreover, we foresee (U)SAXS and WAXS experiments to investigate, in the liquid phase, the structure of silica-OMs composites formed via co-precipitation and adsorption, trying to induce diagenetic P-T conditions.
Our proposal may mean an expansion in materials sciences, mineralogy, condensed material structure, and crystallography, disciplines that so far indicate zeolites, clay minerals, oxides and synthetic phases of SiO2 as porous materials. Characterization of porosity is critical in applications in nanotechnology, pharmaceuticals, energy storage, among others.

Collaborative research (USP and Advanced Photon Source, USA) dealing with with porosity in silica-rich sedimentary rocks and how porosity can preserve organic molecules (OMs) and microfossils across geological timescales in this type of rock. Some models explain the preservation of OMs because of the interaction between microorganisms and silicamatrix. Nevertheless, such interactions only account for the first stages of the formation of silica-OMsaggregates. Such aggregates are unconsolidated material. Then, to become very-rich silica sedimentaryrock (i.e., a chert), this aggregate must undergo burial and silica diagenesis. Only via silica diagenesis isolation of pore-network can be attained given this process, driven by the conversion ofamorphous silica to quartz, leading to precipitation in larger pores, meanwhile favoring dissolution in the smallerones generating a reduction of permeability.Despite the evidence described in previous sections, studies dealing with chert explain the preservation of OMs asa chemical phenomenon, not including the microstructural variable into their models. Then, we propose tocharacterize chert samples of ages ranging between 134 million years (Ma) and 1870 Ma to gain insights into therole of silica microstructure in OMs preservation as a geological timescale phenomenon. Based on experimentalmodels, we hypothesize that the preservation is a pore-size-dependent phenomenon possibly constrainedto meso (between 2 and 50 nm) and micropores (less than 2 nm).

Desenvolvimento de análises isotópicas in situ de Sr, Nd e Hf aplicadas em apatita, feldspatos e carbonatos, para uso na exploração e produção de petróleo.

Projeto Temático, financiado pelo CNPq, que apoia o INCT de mesmo nome, e tem por objetivo o desenvolvimento de técnicas analíticas isotópicas para ser aplicada em trabalhos geológicos relacionados a exploração de óleo e gás. Essas técnicas são implantadas nos laboratórios de geologia isotópica da USP, UNB, UFPa e UFRGS e disponibilizadas para a comunidade científica e para o setor produtivo, no caso para as copmpanias de petróleo que atuam em território brasileiro

Projeto Temático, financiado pela FAPESP, que apoia o INCT de mesmo nome, e tem por objetivo o desenvolvimento de técnicas analíticas isotópicas para ser aplicada em trabalhos geológicos relacionados a exploração de óleo e gás. Essas técnicas são implantadas nos laboratórios de geologia isotópica da USP, UNB, UFPa e UFRGS e disponibilizadas para a comunidade científica e para o setor produtivo, no caso para as copmpanias de petróleo que atuam em território brasileiro