Insight into the Distribution of High-pressure Shock Metamorphism in Rubble-pile Asteroids

Funding Information: This work was supported by the Academy of Finland, project Nos. 293975 and 335595, the European Regional Development Fund, the Mobilitas Pluss programme (grant No. MOBJD639), and the NASA Solar System Exploration Research Virtual Institute Center for Lunar and Asteroid Surface Science, and it was conducted within institutional support RVO 67985831 of the Institute of Geology of the Czech Academy of Sciences. R.L. appreciates funding from the European Union’s Horizon 2020 research and innovation program, NEO-MAPP, grant agreement No. 870377. Publisher Copyright: © 2022. The Author(s). Published by the American Astronomical Society.Shock metamorphism in ordinary chondrites allows for reconstructing impact events between asteroids in the main asteroid belt. Shock-darkening of ordinary chondrites occurs at the onset of complete shock melting of the rock (>70 GPa) or injection of sulfide and metal melt into the cracks within solid silicates (∼50 GPa). Darkening of ordinary chondrites masks diagnostic silicate features observed in the reflectance spectrum of S-complex asteroids so they appear similar to C/X-complex asteroids. In this work, we investigate the shock pressure and associated metamorphism pattern in rubble-pile asteroids at impact velocities of 4–10 km s−1. We use the iSALE shock physics code and implement two-dimensional models with simplified properties in order to quantify the influence of the following parameters on shock-darkening efficiency: impact velocity, porosity within the asteroid, impactor size, and ejection efficiency. We observe that, in rubble-pile asteroids, the velocity and size of the impactor are the constraining parameters in recording high-grade shock metamorphism. Yet, the recorded fraction of higher shock stages remains low (<0.2). Varying the porosity of the boulders from 10% to 30% does not significantly affect the distribution of pressure and fraction of shock-darkened material. The pressure distribution in rubble-pile asteroids is very similar to that of monolithic asteroids with the same porosity. Thus, producing significant volumes of high-degree shocked ordinary chondrites requires strong collision events (impact velocities above 8 km s−1 and/or large sizes of impactors). A large amount of asteroid material escapes during an impact event (up to 90%); however, only a small portion of the escaping material is shock-darkened (6%).Peer reviewe

Presence and evolution of NET markers and DAMPS in critically ill COVID-19 patients

Resumen del trabajo presentado en el 4th European Congress on Thrombosis and Haemostasis, celebrado en Gante (Bélgica), los días 14 y 15 de octubre de 2021Background: The coronavirus disease (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection presents with a wide range of disease symptoms. In the more severe patients, COVID-19 is associated with respiratory failure, neutrophil extracellular trap (NET) formation, and multiple organ failure (MOF). Aims: We investigated the presence and evolution of several damage associated molecular patterns (DAMPs) neutrophil markers and immune modulators in a group of 100 COVID-19-positive ICU patients. Methods: Citrated plasma was collected from adult patients with confirmed COVID-19 by PCR detection of SARS-CoV-2 E and N-genes in nasopharyngeal swabs admitted to the intensive care unit (ICU) at Uppsala University hospital, Sweden. Written informed consent was obtained from the patients, or next of kin if the patient was unable to give consent. The Declaration of Helsinki and its subsequent revisions were followed. Plasma concentration of cell free DNA (cfDNA), extracellular histone H3 (H3), neutrophil elastase (NE), myeloperoxidase (MPO) and the cfDNA-MPO complex, and the immune modulators GAS6, and sAXL were measured in all COVID-19-positive and in COVID-19-negative patients and healthy controls. We determined marker levels upon admission, of their evolution, and correlation with disease severity, organ failure, thromboembolic events, mortality, and other blood parameters. Results: The level of cfDNA, H3, NE, MPO, cfDNA-MPO complex, GAS6, and sAXL were all significantly increased in plasma of COVID-19 patients compared to controls. Importantly, a diminution of cfDNA and GAS6 levels over time was observed in patients surviving 30 days after ICU admission. Histone H3 levels were detected in 40% of the COVID-19 patient plasma at ICU admission and the presence of histone H3 during ICU stay was associated with an increased risk of thromboembolic events and secondary infection. Though NET markers were not predictive of 30-day mortality, they correlated with several parameters of tissue damage and neutrophil counts. Summary/Conclusion: The increased presence of cfDNA, H3 and NE, MPO, and MPO-DNA illustrates the severity of cellular damage and indicates activation of NETosis in severe COVID-19 ICU patients. The evolution of cfDNA and Gas6 is able to predict disease prognosis of severely ill COVID-19 patients, where GAS6 appears to be part of an early activated mechanism in response to COVID-19. These data support treatment aimed at the reduction of NET formation in severe COVID-19 patients

Markers of NETosis and DAMPs are altered in critically ill COVID-19 patients

Background Coronavirus disease 19 (COVID-19) is known to present with disease severities of varying degree. In its most severe form, infection may lead to respiratory failure and multi-organ dysfunction. Here we study the levels of extracellular histone H3 (H3), neutrophil elastase (NE) and cfDNA in relation to other plasma parameters, including the immune modulators GAS6 and AXL, ICU scoring systems and mortality in patients with severe COVID-19. Methods We measured plasma H3, NE, cfDNA, GAS6 and AXL concentration in plasma of 83 COVID-19-positive and 11 COVID-19-negative patients at admission to the Intensive Care Unit (ICU) at the Uppsala University hospital, a tertiary hospital in Sweden and a total of 333 samples obtained from these patients during the ICU-stay. We determined their correlation with disease severity, organ failure, mortality and other blood parameters. Results H3, NE, cfDNA, GAS6 and AXL were increased in plasma of COVID-19 patients compared to controls. cfDNA and GAS6 decreased in time in in patients surviving to 30 days post ICU admission. Plasma H3 was a common feature of COVID-19 patients, detected in 40% of the patients at ICU admission. Although these measures were not predictive of the final outcome of the disease, they correlated well with parameters of tissue damage (H3 and cfDNA) and neutrophil counts (NE). A subset of samples displayed H3 processing, possibly due to proteolysis. Conclusions Elevated H3 and cfDNA levels in COVID-19 patients illustrate the severity of the cellular damage observed in critically ill COVID-19 patients. The increase in NE indicates the important role of neutrophil response and the process of NETosis in the disease. GAS6 appears as part of an early activated mechanism of response in Covid-19.The study was supported through grants from the dedSciLifeLab/KAW national COVID-19 research program project grant (MH), by Scilifelab, the Knut and Alice Wallenberg Foundation and in part by the Swedish Research Council (RF, grant no 2014-02569 and 2014-07606), and the Netherlands Thrombosis Foundation (GN).N

Decreased renal perfusion during acute kidney injury in critical COVID-19 assessed by magnetic resonance imaging: a prospective case control study

Abstract: Background: Renal hypoperfusion has been suggested to contribute to the development of acute kidney injury (AKI) in critical COVID-19. However, limited data exist to support this. We aim to investigate the differences in renal perfusion, oxygenation and water diffusion using multiparametric magnetic resonance imaging in critically ill COVID-19 patients with and without AKI. Methods: A prospective case–control study where patients without prior kidney disease treated in intensive care for respiratory failure due to COVID-19 were examined. Kidney Disease: Improving Global Outcomes Creatinine criteria were used for group allocation. Main comparisons were tested using Mann–Whitney U test. Results: Nineteen patients were examined, ten with AKI and nine without AKI. Patients with AKI were examined in median 1 [0–2] day after criteria fulfillment. Age and baseline Plasma-Creatinine were similar in both groups. Total renal blood flow was lower in patients with AKI compared with patients without (median 645 quartile range [423–753] vs. 859 [746–920] ml/min, p = 0.037). Regional perfusion was reduced in both cortex (76 [51–112] vs. 146 [123–169] ml/100 g/min, p = 0.015) and medulla (28 [18–47] vs. 47 [38–73] ml/100 g/min, p = 0.03). Renal venous saturation was similar in both groups (72% [64–75] vs. 72% [63–84], ns.), as was regional oxygenation (R2*) in cortex (17 [16–19] vs. 17 [16–18] 1/s, ns.) and medulla (29 [24–39] vs. 27 [23–29] 1/s, ns.). Conclusions: In critically ill COVID-19 patients with AKI, the total, cortical and medullary renal blood flows were reduced compared with similar patients without AKI, whereas no differences in renal oxygenation were demonstrable in this setting. Trial registration ClinicalTrials ID: NCT02765191, registered May 6 2014 and updated May 7 2020. Graphic Abstract

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Aspects of renal blood flow and oxygenation in acute kidney injury during severe infections

Acute kidney injury (AKI) is a common complication in patients treated in the intensive care unit (ICU). Severe infections/sepsis is the most common aetiology, and about half of patients treated in the ICU due to sepsis are affected. Although AKI often resolves over time, the development of AKI decreases the chances of surviving. This thesis aims to investigate mechanisms of AKI development related to renal blood flow and oxygenation, by using both animal experiments and novel techniques available to examine patients. In Paper I, anaesthetised sheep were randomised to receive a bacterial infusion for 29 hours, or serve as controls. Isolated mitochondria from the animals’ renal cortex were investigated in vitro, at the beginning, and at the end of the experiment. Renal function deteriorated significantly in sheep with sepsis compared with the controls, and mitochondrial dysfunction by sepsis, comprised of a reduction of the RCR and an increased CII/CI-relation in State 3, was demonstrated in the sepsis group at the end of the experiment. However, renal cortical mitochondrial efficiency and uncoupling was unaffected by sepsis and cannot explain the discrepancy between oxygen consumption and tubular transport. Paper II described and characterised AKI during the novel infection COVID-19, in a prospective cohort study of 57 patients in the ICU. Biomarkers for renal damage were measured in urine from 52 of the study participants. The results show that 89% of the study participants developed AKI. Oliguria was common and occurred early after ICU admission. The biomarkers in the urine were generally elevated, however, with only minor differences between patients stratified by severity of AKI. In Paper III, 19 patients in the ICU due to COVID-19 were examined with magnetic resonance imaging (MRI). Renal blood flows, oxygenation, and water content were measured. The results show that patients with AKI had lower renal blood flows, both in the cortex and medulla, compared with those without. However, no differences regarding oxygenation or water content was demonstrated. Paper IV investigated whether plasma expansion could affect renal blood flows in 17 of the study participants in Paper III. Ringer‘s acetate (7.5 ml/kg) was infused and the measurement with the magnetic camera was repeated. The results show that renal blood flows did not increase, either in patients with or without AKI, even though the increase in circulating blood volume resulted in higher blood pressure. However, patients without AKI had a lower perfusion in the renal medulla after plasma expansion

Aspects of renal blood flow and oxygenation in acute kidney injury during severe infections

Acute kidney injury (AKI) is a common complication in patients treated in the intensive care unit (ICU). Severe infections/sepsis is the most common aetiology, and about half of patients treated in the ICU due to sepsis are affected. Although AKI often resolves over time, the development of AKI decreases the chances of surviving. This thesis aims to investigate mechanisms of AKI development related to renal blood flow and oxygenation, by using both animal experiments and novel techniques available to examine patients. In Paper I, anaesthetised sheep were randomised to receive a bacterial infusion for 29 hours, or serve as controls. Isolated mitochondria from the animals’ renal cortex were investigated in vitro, at the beginning, and at the end of the experiment. Renal function deteriorated significantly in sheep with sepsis compared with the controls, and mitochondrial dysfunction by sepsis, comprised of a reduction of the RCR and an increased CII/CI-relation in State 3, was demonstrated in the sepsis group at the end of the experiment. However, renal cortical mitochondrial efficiency and uncoupling was unaffected by sepsis and cannot explain the discrepancy between oxygen consumption and tubular transport. Paper II described and characterised AKI during the novel infection COVID-19, in a prospective cohort study of 57 patients in the ICU. Biomarkers for renal damage were measured in urine from 52 of the study participants. The results show that 89% of the study participants developed AKI. Oliguria was common and occurred early after ICU admission. The biomarkers in the urine were generally elevated, however, with only minor differences between patients stratified by severity of AKI. In Paper III, 19 patients in the ICU due to COVID-19 were examined with magnetic resonance imaging (MRI). Renal blood flows, oxygenation, and water content were measured. The results show that patients with AKI had lower renal blood flows, both in the cortex and medulla, compared with those without. However, no differences regarding oxygenation or water content was demonstrated. Paper IV investigated whether plasma expansion could affect renal blood flows in 17 of the study participants in Paper III. Ringer‘s acetate (7.5 ml/kg) was infused and the measurement with the magnetic camera was repeated. The results show that renal blood flows did not increase, either in patients with or without AKI, even though the increase in circulating blood volume resulted in higher blood pressure. However, patients without AKI had a lower perfusion in the renal medulla after plasma expansion