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Abstract The latest Triassic was characterised by protracted biotic extinctions concluding in the End-Triassic Extinction (~ 200 Ma) and a global carbon cycle perturbation. The onset of declining diversity is closely related to reducing conditions that spread globally from upper Sevatian (uppermost Norian) to across the Norian-Rhaetian boundary, likely triggered by unusually high volcanic activity. We correlate significant organic carbon cycle perturbations to an increase of CO2 in the ocean–atmosphere system, likely outgassed by the Angayucham igneous province, the onset of which is indicated by the initiation of a rapid decline in 87Sr/86Sr and 188Os/187Os seawater values. A possible causal mechanism involves elevated CO2 levels causing global warming and accelerating chemical weathering, which increased nutrient discharge to the oceans and greatly increased biological productivity. Higher export production and oxidation of organic matter led to a global O2 decrease in marine water across the Norian/Rhaetian boundary (NRB). Biotic consequences of dysoxia/anoxia include worldwide extinctions in some fossil groups, such as bivalves, ammonoids, conodonts, radiolarians.

Abstract Objective Biallelic mutations in PRDX3 have been linked to autosomal recessive spinocerebellar ataxia type 32. In this study, which aims to contribute to the growing body of knowledge on this rare disease, we identified two unrelated patients with mutations in PRDX3. We explored the impact of PRDX3 mutation in patient skin fibroblasts and the role of the gene in neurodevelopment. Methods We performed trio exome sequencing that identified mutations in PRDX3 in two unrelated patients. We also performed functional studies in patient skin fibroblasts and generated a “crispant” zebrafish (Danio rerio) model to investigate the role of the gene during nervous system development. Results Our study reports two additional patients. Patient 1 is a 19‐year‐old male who showed a novel homozygous c.525_535delGTTAGAAGGTT (p. Leu176TrpfsTer11) mutation as the genetic cause of cerebellar ataxia. Patient 2 is a 20‐year‐old male who was found to present the known c.425C>G/p. Ala142Gly variant in compound heterozygosity with the p. Leu176TrpfsTer11 one. While the fibroblast model failed to recapitulate the pathological features associated with PRDX3 loss of function, our functional characterization of the prdx3 zebrafish model revealed motor defects, increased susceptibility to reactive oxygen species‐triggered apoptosis, and an impaired oxygen consumption rate. Conclusions We identified a new variant, thereby expanding the genetic spectrum of PRDX3‐related disease. We developed a novel zebrafish model to investigate the consequences of prdx3 depletion on neurodevelopment and thus offered a potential new tool for identifying new treatment opportunities.

Patients with Parkinson’s disease (PD), often elderly with various comorbidities, may require a continuous intestinal infusion of carbidopa/levodopa gel by the placement of a percutaneous endoscopic gastrostomy (PEG) with a jejunal tube (PEG-J) to improve their motor outcome and quality of life. However, it is unclear what is the best procedural sedation protocol for PEG-J procedures. Fifty patients with PD and indication for PEG-J procedure (implantation, replacement, removal) underwent, from 2017 to 2022, a sedation protocol characterized by premedication with atropine (0.01 mg/Kg i.v.), midazolam (0.015–0.03 mg/Kg i.v.) and induction with bolus propofol (0.5–1 mg/Kg i.v.) as well as, finally, sedation with continuous infusion propofol (2–5 mg/Kg/h i.v.) by Target Controlled Infusion (TCI) technique. Ninety-eight per cent of patients experienced no intraprocedural or peri-procedural adverse events. All the procedures were technically successful. A good discharge time was recorded. The vital parameters recorded during the procedure did not vary significantly. A PEG-J procedure conducted within 30 min showed a significant advantage over end-tidal carbon dioxide (EtCO2). Indeed, the latter showed some predictive behavior (OR: 1.318, 95% CI 1.075–1.615, p = 0.008). In the real world, this sedation protocol showed a good safety and effectiveness profile, even with reduced doses of midazolam and a TCI propofol technique in moderate sedation.

Site U1501 of International Ocean Discovery Program (IODP) Expedition 368 locates on a broad regional basement high in the northern margin of the South China Sea (SCS). This study refines the chronostratigraphy of the upper 160 m sedimentary succession from Hole U1501C using paleomagnetic measurements and cyclostratigraphic analysis on the Natural Gamma Radiation (NGR) data. Rock magnetic analysis displays that the magnetic signal of the sediments is mainly carried by single-domain (SD) and multi-domain (MD) magnetite. A total of 12 geomagnetic reversals are identified and correlated to the geomagnetic polarity time scale (GPTS) in Geologic Time Scale 2020 (GTS 2020), combining biostratigraphic data and planktonic foraminiferal oxygen records. The Milankovitch cycles of 405-kyr long orbital eccentricity, ∼100-kyr short orbital eccentricity, and obliquity cycles are identified in the NGR profile. A 15.54 Myr astronomical time scale is constructed by tuning the short eccentricity cycles filtered from the NGR profiles to the La2010 astronomical solution with the constraints of the magnetostratigraphic results, biostratigraphic age datum and planktonic foraminiferal oxygen records. This new high-resolution age model provides a new temporal constraint on the tectonic and paleoenvironmental evolution in the South China Sea.

The anisotropy of magnetic susceptibility (AMS) in sedimentary rocks results from depositional, diagenetic, syn- and post-sedimentary processes that affect magnetic grains. Some studies have also shown the potential role played by post-depositional fluid flow in detrital and carbonate formations. Here we present a new case study of Middle-Upper Jurassic sandstones where secondary iron oxides, precipitated from fluids that migrated through pores, give rise to the AMS. These sandstones are well exposed in the Uncompahgre Uplift region of the Central Colorado Trough, Colorado. The magnetic foliation of these undeformed, subhorizontal strata consistently strike NE-SW over a large distance with an average 45° dip to the SE. This steep AMS fabric is oblique with respect to the regional subhorizontal bedding and therefore does not reflect the primary sedimentary fabric. Also, outcrop-scale and microscopic observations show a lack of post-depositional plastic (undulose extinction) or pressure-solution (stylolites) deformation microstructures in these sandstones, hence precluding a tectonic origin. The combination of magnetic hysteresis, isothermal remanent magnetization, and thermal demagnetization of the natural remanent magnetization indicate that these rocks carry a chemical remanent magnetization born primarily by hematite and goethite. High-field magnetic hysteresis and electron microscopy indicate that detrital magnetite and authigenic hematite are the main contributors to the AMS. These results show that post-depositional iron remobilization through these porous sandstones took place due to the action of percolating fluids which may have started as early as Late Cretaceous along with the Uncompahgre Uplift. The AMS fabric of porous sandstones does not systematically represent depositional or deformation processes, and caution is urged in the interpretation of magnetic fabrics in these types of reservoir rock. Conversely, understanding these fabrics may advance our knowledge of fluid flow in porous sandstones and may have applications in hydrocarbon exploration.

We investigated the geochemical and rock magnetic properties of the magnetostratigraphically-calibrated Pignola-Abriola section (Italy) in order to understand the climatic perturbations that characterize the late Norian-early Rhaetian interval (Late Triassic). We performed experiments on anhysteretic and isothermal remanence (ARM, IRM), and on magnetic susceptibility (?), to obtain the rock magnetic parameters necessary for our paleoclimatic investigation. An episode of increase in relative quantity of hematite, suggesting enhanced subaerial oxidation of iron minerals, was identified in the Norian from ~217 Ma in the Alaunian up to ~211 Ma in the early Sevatian, followed by a decline up to 207-206 Ma at the end of the Norian (late Sevatian). The results of geochemical and multivariate statistical analyses support a long-term increase and reduction in rock weathering, confirming and extending previous 87Sr/86Sr data from the Pizzo Mondello section (Italy). Possible causes of these long-term weathering trends are the multiphase uplifting of the Cimmerian orogen, occurring at mid northern latitudes along the southern margin of Asia in the Late Triassic, and/or the northward motion of Pangea across the equatorial humid belt. Rapid excursions in oxidized iron minerals have also been observed across the Norian/Rhaetian boundary, the origin of which has still to be determined. [ABSTRACT FROM AUTHOR]