Publications by authors named "Alexis Castillo"

In seafood, the study of metal(loid)s is essential to assess their toxicity and to establish risks of human exposure. This study investigates the content of As, Cd, Cu, Ni and Pb in Concholepas concholepas in a coastal environmental sacrifice zone (Chile) to assess potential human-health risks by consumption of C. concholepas.

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Taxonomic and functional microbial communities may respond differently to anthropogenic coastal impacts, but ecological quality monitoring assessments using environmental DNA and RNA (eDNA/eRNA) in response to pollution are poorly understood. In the present study, we investigated the utility of the co-occurrence network approach's to comprehensively explore both structure and potential functions of benthic marine microbial communities and their responses to Cu and Fe fractioning from two sediment deposition coastal zones of northern Chile 16S rRNA gene metabarcoding. The results revealed substantial differences in the microbial communities, with the predominance of two distinct module hubs based on study zone.

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The high-Andean mountain of northern Chile host numerous water systems that is in risk due to increased mining activities. Total and dissolved Cd, Cr, Cu, Hg, Ni, Pb, Se, and Zn in water, and Cd, Cu, Fe, Ni, Pb, Zn, As, Mo, Al, and V in sediments of 21 aquatic systems (rivers, saline lakes, salt flats), were studied. The presence of Pb, Cd, and As in waters and sediments could be explained, in part, by mining activities.

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Long-term cognitive impairment (LTCI) is a phenomenon predominantly seen in patients within intensive care units (ICU) that causes chronic dysfunction, defined as new or worsening deficits in memory, attention, mental processing speed, executive function, intellectual function, and visual-spatial abilities for over 12 months, inhibiting the necessary return to baseline function without appropriate intervention. Our objective is to provide a guideline of nursing strategies to reduce LTCI through different studies that evaluate pharmacological and non-pharmacological methods. Current literature demonstrates that pharmacotherapy focused on neuronal protection as well as robust physical therapy regimens and regulated sleep schedules show promise in strengthening cognitive function and reducing LTCI.

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Mejillones Bay is a coastal ecosystem situated in an oxygen-deficient upwelling area impacted by mining activities in the coastal desert region of northern Chile, where conspicuous microbial life develops in the sediments. Herein, heavy metal (loid)s (HMs) such as Cu, Pb, As, Zn, Al, Fe, Cd, Mo, Ni and V as well as benthic microbial communities were studied using spectrometry and iTag-16 S rRNA sequencing. Samples were taken from two contrasting sedimentary localities in the Bay named Punta Rieles (PR) and Punta Chacaya (PC) within 10-50 m water-depth gradient.

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Two catalytic cascade cyclization methods (radical and 'cationic) to obtain aromatic polycyclic diterpenes hydroxylated at C3 starting from aromatic epoxypolyprenes were developed. The catalytic use of the Lewis superacid bismuth triflate produces a good yield of cyclized 2 from epoxypolyprene 3. This researchmay well direct future efforts to the synthesis of bioactive natural products.

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An easy procedure to obtain extracts enriched in trixagol monomalonylesther (1) from aerial parts of the plant Belladia trixago chemotype Trix was developed. Preparation of (+)-dihydro-gamma-ionone (4) was carried out directly from the extracts with good yields by selective oxidation. Other interesting odorant products as alpha-ambrinol (5), ambraldehyde (6) and the tricyclic compound 7 were synthesized very efficiently using (4) as intermediate.

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Article Synopsis
  • Neutron diffraction is more effective than X-ray diffraction for pinpointing hydrogen (H) atom locations in biological structures, especially in proteins like Pyrococcus furiosus rubredoxin.
  • The study compares high-resolution neutron data (1.65 A) and X-ray data (1.1 A) to demonstrate that neutron data are about eight times more reliable for determining positions of deuterium (D) atoms than X-ray data at various temperatures.
  • Joint analysis of both X-ray and neutron data significantly improves the accuracy of identifying D atom positions, identifying approximately 90% of positions for D-rubredoxin and 80% for HD-rubredoxin, compared to very low percentages with X-ray data alone.
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Entrapment of biomolecules in silica-derived sol-gels has grown into a vibrant area of research since it was originally demonstrated. However, accessing the consequences of entrapment on biomolecules and the gel structure remains a major challenge in characterizing these biohybrid materials. We present the first demonstration that it is possible with small-angle neutron scattering (SANS) to study the conformation of dilute proteins that are entrapped in transparent and dense sol-gels.

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Synopsis of recent research by authors named "Alexis Castillo"

  • - Alexis Castillo's recent research primarily focuses on the assessment of metal(loid)s in various marine and aquatic environments in Chile, emphasizing the potential risks to human health and biodiversity due to anthropogenic activities, particularly mining.
  • - A key study investigated the contamination of Concholepas concholepas (a marine mollusk) with heavy metals such as As, Cd, Cu, Ni, and Pb, highlighting the potential health hazards associated with consumption in coastal sacrifice zones.
  • - Castillo has also explored the dynamics of benthic microbial communities in response to heavy metal contamination, utilizing advanced methodologies like environmental DNA (eDNA) metabarcoding, contributing to a better understanding of ecological responses in sensitive coastal ecosystems.