Distinct Expression Levels and Patterns of Stem Cell Marker, Aldehyde Dehydrogenase Isoform 1 (ALDH1), in Human Epithelial Cancers

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Overview of the MOSAiC expedition: Physical oceanography

Arctic Ocean properties and processes are highly relevant to the regional and global coupled climate system, yet still scarcely observed, especially in winter. Team OCEAN conducted a full year of physical oceanography observations as part of the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC), a drift with the Arctic sea ice from October 2019 to September 2020. An international team designed and implemented the program to characterize the Arctic Ocean system in unprecedented detail, from the seafloor to the air-sea ice-ocean interface, from sub-mesoscales to pan-Arctic. The oceanographic measurements were coordinated with the other teams to explore the ocean physics and linkages to the climate and ecosystem. This paper introduces the major components of the physical oceanography program and complements the other team overviews of the MOSAiC observational program. Team OCEAN’s sampling strategy was designed around hydrographic ship-, ice- and autonomous platform-based measurements to improve the understanding of regional circulation and mixing processes. Measurements were carried out both routinely, with a regular schedule, and in response to storms or opening leads. Here we present alongdrift time series of hydrographic properties, allowing insights into the seasonal and regional evolution of the water column from winter in the Laptev Sea to early summer in Fram Strait: freshening of the surface, deepening of the mixed layer, increase in temperature and salinity of the Atlantic Water. We also highlight the presence of Canada Basin deep water intrusions and a surface meltwater layer in leads. MOSAiC most likely was the most comprehensive program ever conducted over the ice-covered Arctic Ocean. While data analysis and interpretation are ongoing, the acquired datasets will support a wide range of physical oceanography and multi-disciplinary research. They will provide a significant foundation for assessing and advancing modeling capabilities in the Arctic Ocean

Genesis of granular calcite in lacustrine fine-grained sedimentary rocks and its indication to volcanic-hydrothermal events: A case study of Permian Lucaogou Formation in Jimusar Sag, Junggar Basin, NW China

Granular calcite is an authigenic mineral in fine-grained sedimentary rocks. Core observation, thin section observation, cathodoluminescence analysis, fluid inclusion analysis, scanning electron microscope (SEM), and isotopic composition analysis were combined to clarify the genesis of granular calcite in the lacustrine fine-grained sedimentary rocks of the Permian Lucaogou Formation in the Jimusar Sag, Junggar Basin. It is found that the granular calcite is distributed with laminated characteristics in fine-grained sedimentary rocks in tuffite zones (or the transitional zone between tuffite and micritic dolomite). Granular calcite has obvious cathodoluminesence band, and it can be divided into three stages. Stage-I calcite, with non-luminesence, high content of Sr element, inclusions containing COS, and homogenization temperature higher than 170 °C, was directly formed from the volcanic-hydrothermal deposition. Stage-II calcite, with bright yellow luminescence, high contents of Fe, Mn and Mg, enrichment of light rare earth elements (LREEs), and high homogenization temperature, was formed by recrystallization of calcareous edges from exhalative hydrothermal deposition. Stage-III calcite, with dark orange luminescence band, high contents of Mg, P, V and other elements, no obvious fractionation among LREEs, and low homogenization temperature, was originated from diagenetic transformation during burial. The granular calcite appears regularly in the vertical direction and its formation temperature decreases from the center to the margin of particles, providing direct evidences for volcanic-hydrothermal events during the deposition of the Lucaogou Formation. The volcanic-hydrothermal event was conducive to the enrichment of organic matters in fine-grained sedimentary rocks of the Lucaogrou Formation, and positive to the development of high-quality source rocks. The volcanic-hydrothermal sediments might generate intergranular pores/fractures during the evolution, creating conditions for the self-generation and self-storage of shale oil

Resveratrol Attenuates Sepsis-Induced Cardiomyopathy in Rats through Anti-Ferroptosis via the Sirt1/Nrf2 Pathway

Background: Sepsis-induced cardiomyopathy (SIC) is a severe myocardial dysfunction secondary to septicemia. It is a major concern owing to the high mortality and morbidity, which are greatly influenced by ferroptosis. Resveratrol (RSV) is a naturally existing agonist of the silent information regulator 1 (Sirt1). It has cardioprotective effects against sepsis-induced myocardial injury, However, the detailed mechanism is unknown. Methods: In this study, cecal ligation and puncture (CLP)-induced septic rats were employed to assess the changes in ferroptosis with RSV administration. According to the different treatments the rats were divided into the following groups: (1) the Sham, (2) CLP, (3) CLP + RSV at various doses (10, 30, and 50 mg/kg), and (4) CLP + Fer-1(a ferroptotic inhibitor) groups. After 24 h, the structure and function of the cardiac system in rats were evaluated, and mitochondrial morphology, ferroptosis-related biomarkers, and the levels of Sirt1/Nrf2 were assessed. Results: The rats that underwent CLP had suffered cardiac dysfunction, accompanied with myocardial damage, impaired mitochondria, elevated lipid peroxidation, and reduced Sirt1/Nrf2 expression in the myocardium. High-dose RSV successfully improved heart function, reversing the abnormalities in a dose-dependent manner. We then used EX527, a selective Sirt1 inhibitor, to further identify the intermediate signaling targets of RSV that regulate ferroptosis. EX527 diminished the curative effects of high-doses RSV. Conclusions: Summarily, our findings suggest a novel mechanism of RSV in reducing SIC: ferroptosis inhibition via upregulation of Sirt1/Nrf2 signaling pathways. This may be an effective therapeutic approach against organ failure in sepsis, particularly SIC

Pre-invasion assessment of potential invasive wood borers on North American tree species in Chinese sentinel gardens

Images and sequences of wood-borers for the manuscript titled "Pre-invasion assessment of potential invasive wood borers on North American tree species in Chinese sentinel gardens"</p

Centennial-scale variability of sea-ice cover in the Chukchi Sea since AD 1850 based on biomarker reconstruction

International audiencePaleo-climate proxy records documenting sea-ice extent are important sources of information to assess the time of emergence and magnitude of on-going changes in the Arctic Ocean and better predict future climate and environmental evolution in that region. In this study, a suite of geochemical tracers including total organic carbon (TOC), total nitrogen (TN), carbon/nitrogen ratio (C/N), stable isotope composition of organic carbon and nitrogen (δ13C, δ15N), and phytoplankton biomarkers (highly branched isoprenoids (HBIs) and sterols) were measured in a marine sediment core to document the sea-ice variability in the Chukchi Sea since the beginning of the Industrial Era. The downcore profile of the sea-ice proxy HBIs suggests a transition from extensive sea ice in the late 19th century to Marginal Ice Zone (MIZ) in AD 1930-1990s and then moderate sea-ice cover since 1990s. Rising of all HBI abundances between AD 1865-1875 indicate a transient retreat of summer ice edge off the shelf followed by a return to near-perennial sea ice till 1920-1930 as revealed by the absence of HBIs and brassicasterol. Sea ice retreat occurred again in AD 1920-1930 and followed by colder decades in 1940s-1960s before a sustained decline since the 1990s. The downcore profile of C/N, δ13 C of organic matter and sterols indicates a gradual increase of terrigenous inputs accelerating during the most recent decades likely due to enhanced fluvial run-off and sediment transport by sediment-laden sea ice. Concomitantly, increasing δ15N values suggest limited nutrient utilization due to enhanced stratification of the surface ocean caused by increased freshening. The role of the Arctic Oscillation (AO), the Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) are discussed to explore potential drivers of the observed sea-ice changes

Diatom composition and fluxes over the Northwind Ridge, western Arctic Ocean: impact of marine surface circulation and sea ice distribution

International audienceOver the last decades, the western Arctic Ocean has undergone unprecedented environmental changes. However, long-term in situ observations of marine phytoplankton are still rare and therefore insufficient to fully characterize their evolutionary trends. This study investigated the diatom fluxes and composition in sediment trap material collected from the Northwind Ridge, western Arctic Ocean, from August 2008 to September 2009. Our data showed that Chaetoceros resting spores were the predominant species, accounting for >40% of the diatom composition. The sea ice diatom group, which included Fossula arctica, Fragilariopsis cylindrus and F. oceanica, dominated the rest of the assemblage throughout the observation period. While diatom fluxes in winter were extremely low, higher flux values were found in summer, and summer 2009 flux values were twice as high as those in 2008. The high total mass and diatom fluxes in summer 2009 were attributed to the combined effect of a weakened Beaufort Gyre, a strengthened Pacific water inflow (PWI) and the distribution pattern of the sea ice. The higher levels of coastal diatoms and terrigenous proxies in summer 2009 were consistent with the intensified PWI. Sea ice diatoms and sea ice biomarker IP25 fluxes were both high during the sea ice melting season and were significantly correlated with each other (r2 = 0.64, p < 0.01). Our data also suggest that sea ice diatoms are prone to selective dissolution in the water column and sediments, implying the existence of biases in diatom assemblage data and subsequently in paleoceanographic reconstructions