As sucessões carbonáticas neoproterozóicas do Cráton do São Francisco e os depósitos de fosfato: correlações e fosfogênese

Neoproterozoic Carbonate Sequences of the São Francisco Craton and the Phosphate Deposits: Correlation and Phosphogenesis. The neoproterozoic carbonate successions of the São Francisco craton are formed by thick carbonate and siliciclastic strata accumulated in epicontinental seaways, and on passive margins. At least two transgressive-regressive sea level cycles have been recognized during the evolution of the carbonate mega-sequences. These successions, represented by the Vazante, Bambuí, and Una Groups, lie above basal glacio-marine diamictites of probable Sturtian age, and an upper glacio-marine diamictite, was observed in upper units of the Vazante Group. The broad similarities of lithofacies, as well as the presence of phosphate and sulfide (Zn,Pb) deposits restricted to narrow stratigraphic intervals, suggest that the Vazante, Bambuí and Una Groups may be correlative. The Sr isotope data from well preserved carbonates and carbonate fluorapatite from each of these successions, ranging from 0.70763 to 0.70794, support the general correlation and are indicative of seawater composition around 650 Ma, although the lower 87Sr/86Sr values of 0.70614 at the Vazante carbonates may suggest that this unit is older than the Bambuí and Una carbonate rocks. Carbon isotope data of carbonate fluorapatite reveal sharp negative excursions between -3.47 and -12.25‰ VPDB in the cratonic area, and between -1.3 and -9.61‰ VPDB in the carbonate fluorapatite hosted by the passive margin Vazante carbonates, suggesting that primary P concentration was accumulated in strong anoxic environments in both geotectonic settings. Carbonate hosting the phosphate deposits in these units are moderately enriched in 13C, ranging from positive δ13C values of +2.0 and +9.6‰ VPDB in the different sections. Primary phosphate accumulations occur above glaciogenic successions. We suggest that these concentrations may be due to high organic productivity after glacial events

δ13C and 87Sr/86Sr of phosphorites from the São Francisco Craton, Brazil: phosphogenesis and correlations

Phosphate accumulations in the São Francisco Craton are found in both the cratonic non-deformed strata, and in the Brasilia Fold Belt, to the west of the cratonic area. The deposits are stratigraphycally controlled and their formation is probably related to a widespread episode during the terminal Proterozoic Era (Cook and Shergold, 1986). These authors suggested that major phosphogenic event followed a period of glaciation, which “could produce a large volume of cold, nutrient-rich water, resulting in a major expansion of organic productivity in the photic zone following the glacial period”

Metabolomics by NMR Combined with Machine Learning to Predict Neoadjuvant Chemotherapy Response for Breast Cancer

Neoadjuvant chemotherapy (NACT) is offered to patients with operable or inoperable breast cancer (BC) to downstage the disease. Clinical responses to NACT may vary depending on a few known clinical and biological features, but the diversity of responses to NACT is not fully understood. In this study, 80 women had their metabolite profiles of pre-treatment sera analyzed for potential NACT response biomarker candidates in combination with immunohistochemical parameters using Nuclear Magnetic Resonance (NMR). Sixty-four percent of the patients were resistant to chemotherapy. NMR, hormonal receptors (HR), human epidermal growth factor receptor 2 (HER2), and the nuclear protein Ki67 were combined through machine learning (ML) to predict the response to NACT. Metabolites such as leucine, formate, valine, and proline, along with hormone receptor status, were discriminants of response to NACT. The glyoxylate and dicarboxylate metabolism was found to be involved in the resistance to NACT. We obtained an accuracy in excess of 80% for the prediction of response to NACT combining metabolomic and tumor profile data. Our results suggest that NMR data can substantially enhance the prediction of response to NACT when used in combination with already known response prediction factors

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P < 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)