A combination of a high sediment input and intense bottom currents often leads to the formation of contourites (sediments deposited or significantly reworked by bottom currents). Both of these ...components are present in the Vema Fracture Zone valley which is the most important passageway for the distribution of the Antarctic Bottom Water from the West to the North-East of the Atlantic. However, no contourite drifts, moats or contourite channels have been found in this region in more than half a century of research. The prevailing sedimentation paradigm postulates that turbidity currents have predominantly governed sedimentation in this region during the Pleistocene. This work describes the first example of contourite depositional system identified in the Vema Fracture Zone. The discovery was made through detailed high-resolution sub-bottom profiling, as well as numerical modeling and direct measurements of bottom current velocities. Such systems are exceptionally uncommon in fracture zones. This study highlights the importance of further research of contourites along the Vema Fracture Zone based on modern concepts of contourite and mixed depositional systems. The work also emphasizes the need to reevaluate the impact of bottom currents on sedimentation in this region, and particularly in the narrow segments of the fracture zone valley.
Analysis of new and existing geophysical data for the Central Indian and Wharton Basins of the Indian Ocean were used to understand the formation and evolution of the Ninetyeast Ridge (NER), ...especially its relationship to the Kerguelen hot spot and the Wharton spreading ridge. Satellite gravity data and magnetic anomalies 34 through 19 define crustal isochrons and show fracture zones striking ∼N5°E. One of these, at 89°E, crosses the ∼N10°E trending NER, impacting the NER morphology. From 77 to 43 Ma the NER lengthened at a rate of ∼118 km/Myr, twice that of the ∼48–58 km/Myr accretion rate of adjacent oceanic crust. This difference can be explained by southward jumps of the Wharton spreading ridge toward the hot spot, which transferred portions of crust from the Antarctic plate to the Indian plate, lengthening the NER. Magnetic anomalies document a small number of large spreading ridge jumps in the ocean crust immediately to the west of the NER, especially two leaving observable 65 and 42 Ma fossil spreading ridges. In contrast, complex magnetic anomaly progressions and morphology imply that smaller spreading ridge jumps occurred at more frequent intervals beneath the NER. Comparison of the NER dates and magnetic anomaly ages implies that the hot spot first emplaced NER volcanoes on the Indian plate at a distance from the Wharton Ridge, but as the northward drifting spreading ridge approached the hot spot, the two interacted, keeping later NER volcanism near the spreading ridge crest by spreading center jumps.
Key Points
Compiled entire magnetic data of the Ninetyeast Ridge, analyzed and interpreted
Discussed the structural and magnetic pattern of the region
Models proposed for Ninetyeast Ridge accretion during ridge‐hot spot interactions
High fluvial input combined with specific topographic and oceanographic settings in the Caspian Sea create favorable conditions for contourite deposition. For the first time in its middle portion, ...contourite deposits have been observed in high-resolution seismic profiles. Various types of contourite drifts and mixed depositional systems have been revealed on the lower slope and in the adjacent basin, some of which are accompanied by sediment wave fields. The deposition of contourites or turbidites and their lateral distribution is controlled by sea-floor topography and oceanographic processes, as well as the modern activity of gravity flows downslope on the western Caucasian slope and in the channel system on the Mangyshlak Sill. The contourite drifts and sediment wave fields form several contourite depositional systems, which seem to merge in the Caspian contourite depositional complex. This occurs near the foot of slopes of the Derbent Basin and is related to the counterclockwise circum-Caspian current in the Middle Caspian Sea. The fact that the Caspian Sea is the largest lake in the world makes this region a significant area for research into the “lake contourites” issue. The Caspian Sea is an important oil-producing area, and sedimentary processes related to the contourite and turbidite can be a source of potential geohazards in the construction and exploitation of underwater engineering structures
The new coronavirus disease, COVID-19, poses complex challenges exacerbated by several factors, with respiratory tissue lesions being notably significant among them. Consequently, there is a pressing ...need to identify informative biological markers that can indicate the severity of the disease. Several studies have highlighted the involvement of proteins such as APOA1, XPNPEP2, ORP150, CUBN, HCII, and CREB3L3 in these respiratory tissue lesions. However, there is a lack of information regarding antibodies to these proteins in the human body, which could potentially serve as valuable diagnostic markers for COVID-19. Simultaneously, it is relevant to select biological fluids that can be obtained without invasive procedures. Urine is one such fluid, but its effect on clinical laboratory analysis is not yet fully understood due to lack of study on its composition.
Methods used in this study are as follows: total serum protein analysis; ELISA on moderate and severe COVID-19 patients' serum and urine; bioinformatic methods: ROC analysis, PCA, SVM.
The levels of antiAPOA1, antiXPNPEP2, antiORP150, antiCUBN, antiHCII, and antiCREB3L3 exhibit gradual fluctuations ranging from moderate to severe in both the serum and urine of COVID-19 patients. However, the diagnostic value of individual anti-protein antibodies is low, in both blood serum and urine. On the contrary, joint detection of these antibodies in patients' serum significantly increases the diagnostic value as demonstrated by the results of principal component analysis (PCA) and support vector machine (SVM). The non-linear regression model achieved an accuracy of 0.833. Furthermore, PCA aided in identifying serum protein markers that have the greatest impact on patient group discrimination. The study revealed that serum serves as a superior analyte for describing protein quantification due to its consistent composition and lack of organic salts and drug residues, which can otherwise affect protein stability.
The linear Ninetyeast Ridge (NER) is the longest oceanic intraplate volcanic edifice and main feature in the Eastern Indian Ocean. Many seamounts are located on the ridge, whose origin and age remain ...unclear due to the lack of samples of the bedrock of which they are composed. Carbonate sedimentary caps on these seamounts prevent their direct geological sampling by dredging, therefore indirect geophysical methods are an alternative. Such integrated geophysical studies (the main methods are multibeam bathymetry and magnetic surveys) were carried out in cruise #42 of the R/V Akademik Boris Petrov in 2017 on a large seamount at the base of the NER’s western slope near 0.5° S. The collected data also includes seismic reflection data that reveal morphology, fault tectonics, depth structure, and an assumed origin of this volcanic feature. The Ninetyeast Ridge was formed by the Kerguelen plume magmatism at 50° S in the giant N-S fault. The seamount studied in cruise #42 of the R/V Akademik Boris Petrov was formed mainly to the north as a result of two-stage magmatism in a transverse strike-slip fault. The first stage (47 Ma) formed the main western part of the seamount at 20° S. The second stage (23 Ma) formed its eastern part at 8° S. The time intervals between the formation of the main massif of the Ninetyeast Ridge and the stages of subsequent magmatism that formed the western and eastern parts of the seamount are approximately 31 and 55 Ma, respectively.
The results of investigations of chemical composition and emission rates of the welding fume, generated during welding using electrodes for copper alloys, are presented with the aim of improvement of ...their sanitary and hygienic characteristics. It is shown that in order to create new grades of welding electrodes with improved hygienic characteristics, it is necessary to have the data of the initial sanitary and hygienic evaluation in accordance with international standards. It was established that the use of binder based on pure lithium liquid glass in the coating of electrodes for welding copper alloys, increases the rate of welding fume emission into the air, as well as the content of manganese and copper oxides in it. The minimum rates of harmful emissions were recorded during the use of sodium-potassium binder, which is recommended for mass production of this type of electrodes.
Recent findings about the evolution of palaeogeographic conditions of the Black Sea during the Holocene have significantly improved our understanding of the profound environmental changes that took ...place around 9ka ago, when the Neoeuxinian Lake reconnected to the global ocean. In contrast to the western and southeastern regions where numerous studies have been recently performed, the northeast region remains relatively under investigated. We carried out the first multi-proxy continuous study of a sediment core (Ak-2575) from the northeastern Black Sea shelf that includes benthic calcareous fossils (ostracods, molluscs and foraminifers), dinoflagellate cysts (dinocysts) and sedimentology, thus providing reconstructions of surface and bottom-water conditions. The age model of the core is based on 10 AMS-14C dates. Calibrated ages are used throughout the manuscript. The first appearance of Mediterranean elements is documented at 9.6cal.kaBP. Our data provide evidence of sustained cohabitation of benthic species of Caspian and Mediterranean origins, represented by different ontogenetic stages, from at least ~7.8 (or even 8.8) to 6.7cal.kaBP with the gradual disappearance of brackish species suggesting a gradual increase in salinity and most likely a change in the salt composition. Dinocyst assemblages show species succession that is coherent across the Black Sea basin, with brackish taxa dominating until ~8.5cal.kaBP and being slowly replaced by euryhaline species. The occurrences of authigenic gypsum crystals, especially abundant at ~7.4 and 6.5cal.kaBP, suggest the temporal appearance of hydrogen sulphide at the shelf edge which during certain periods appears to reduce the abundance of benthic fauna.
•The first well-dated Holocene multi-proxy record from the NE Black Sea shelf•Investigates changes in both surface and bottom-water conditions•Highlights the early appearance of marine ostracods immediately after reconnection•Demonstrates the cohabitation of species of Caspian and Mediterranean origin•Records the occasional upwelling of hydrogen sulphide at the shelf edge
To study overall drug resistance genes (resistome) in the human gut microbiome and the changes in these genes during COVID-19 in-hospital therapy.
A single-center retrospective cohort study was ...conducted. Only cases with laboratory-confirmed SARS-CoV-2 RNA using polymerase chain reaction in oro-/nasopharyngeal swab samples were subject to analysis. The patients with a documented history of or current comorbidities of the hepatobiliary system, malignant neoplasms of any localization, systemic and autoimmune diseases, as well as pregnant women were excluded. Feces were collected from all study subjects for subsequent metagenomic sequencing. The final cohort was divided into two groups depending on the disease severity: mild (group 1) and severe (group 2). Within group 2, five subgroups were formed, depending on the use of antibacterial drugs (ABD): group 2A (receiving ABD), group 2AC (receiving ABD before hospitalization), group 2AD (receiving ABD during hospitalization), group 2AE (receiving ABD during and before hospitalization), group 2B (not receiving ABD).
The median number of antibiotic resistance (ABR) genes (cumulative at all time points) was significantly higher in the group of patients treated with ABD: 81.0 (95% CI 73.8-84.5) vs. 51.0 (95% CI 31.1-68.4). In the group of patients treated with ABD (2A), the average number of multidrug resistance genes (efflux systems) was significantly higher than in controls (group 2B): 47.0 (95% CI 46.0-51.2) vs. 21.5 (95% CI 7.0-43.9). Patients with severe coronavirus infection tended to have a higher median number of ABR genes but without statistical significance. Patients in the severe COVID-19 group who did not receive ABD before and during hospitalization also had more resistance genes than the patients in the comparison group.
This study demonstrated that fewer ABR genes were identified in the group with a milder disease than in the group with a more severe disease associated with more ABR genes, with the following five being the most common:
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The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has significantly impacted global healthcare, underscoring the importance of exploring the virus's effects on infected individuals beyond ...treatments and vaccines. Notably, recent findings suggest that SARS-CoV-2 can infect the gut, thereby altering the gut microbiota. This study aimed to analyze the gut microbiota composition differences between COVID-19 patients experiencing mild and severe symptoms. We conducted 16S rRNA metagenomic sequencing on fecal samples from 49 mild and 43 severe COVID-19 cases upon hospital admission. Our analysis identified a differential abundance of specific bacterial species associated with the severity of the disease. Severely affected patients showed an association with
,
, and others, while milder cases were linked to
,
,
, and additional species. Furthermore, a network analysis using SPIEC-EASI indicated keystone taxa and highlighted structural differences in bacterial connectivity, with a notable disruption in the severe group. Our study highlights the diverse impacts of SARS-CoV-2 on the gut microbiome among both mild and severe COVID-19 patients, showcasing a spectrum of microbial responses to the virus. Importantly, these findings align, to some extent, with observations from other studies on COVID-19 gut microbiomes, despite variations in methodologies. The findings from this study, based on retrospective data, establish a foundation for future prospective research to confirm the role of the gut microbiome as a predictive biomarker for the severity of COVID-19.
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