Reconstruction of dissolved oxygen in the Indian Ocean from 1980 to 2019 based on machine learning techniques

Oceanic dissolved oxygen (DO) decline in the Indian Ocean has profound implications for Earth’s climate and human habitation in Eurasia and Africa. Owing to sparse observations, there is little research on DO variations, regional comparisons, and its relationship with marine environmental changes in the entire Indian Ocean. In this study, we applied different machine learning algorithms to fit regression models between measured DO, ocean reanalysis physical variables, and spatiotemporal variables. We utilized the Extremely Randomized Trees (ERT) model with the best performance, inputting complete reanalysis data and spatiotemporal information to reconstruct a four-dimensional DO dataset of the Indian Ocean during 1980–2019. The evaluation results showed that the ERT-based DO dataset was superior to the DO simulations in Earth System Models across different time and space. Furthermore, we assessed the spatiotemporal variations in reconstructed DO dataset. DO decline and oxygen-minimum zone (OMZ) expansion were prominent in the Arabian Sea, Bay of Bengal, and Equatorial Indian Ocean. Through correlation analysis, we found that temperature and salinity changes related to solubility primarily control the oxygen decrease in the middle and deep sea. However, the complicated factors with solubility change, vertical mixing, and circulation govern the oxygen increase in the upper and middle sea. Finally, we conducted a volume integral to estimate the oxygen content in the Indian Ocean. Overall, a deoxygenation trend of −141.5 ± 15.1 Tmol dec−1 was estimated over four decades, with a slowdown trend of −68.9 ± 31.3 Tmol dec−1 after 2000. Under global warming and climate change, OMZ expanding and deoxygenation in the Indian Ocean are gradually mitigating. This study enhances our understanding of DO dynamics of the Indian Ocean in response to deoxygenation

BlyS is up-regulated by hypoxia and promotes migration of human breast cancer cells

<p>Abstract</p> <p>Background</p> <p>The role of B Lymphocyte Stimulator (BLyS) in the survival of malignant B cells and the maintenance of normal B cell development and homeostasis has been intensively studied in the literature. However, the influence of BLyS on breast cancer progression remains unclear. The study aimed to investigate the effect of hypoxia on BLyS regulation, cell migratory response to BLyS and the possible molecular mechanisms.</p> <p>Methods</p> <p>In this study, we examined the role of BLyS in the migration of human breast cancer cells by transwell assay. We also explored whether BLyS and its receptors expressed in human breast cancer cell lines by immunofluorescence and Western Blotting. Then we detected the expression level of BLyS in both normoxic and hypoxic conditions by real time-PCR and Western Blotting. Pathways involved were confirmed by Western Blotting, immunofluorescence, transwell assay and luciferase assay.</p> <p>Results</p> <p>According to our study, the expression level of BlyS was increased in human breast cancer cell lines in hypoxic conditions. Up-regulation of this protein led to activation and nuclear translocation of NF-kappa B p65. We also found that the number of migrated cells was increased in the presence of BLyS and inhibition of phosphorylation of Akt attenuated the enhanced migratory response.</p> <p>Conclusions</p> <p>It suggested that better understanding of BLyS, an immunopotentiator, may offer a potential therapeutic target for the treatment of human breast cancers. In addition, BLyS promoted breast cancer cells migration, underscoring the necessity of appropriate applications of immunopotentiators to cancer treatment.</p

Plant Root Exudates Are Involved in Bacillus cereus AR156 Mediated Biocontrol Against Ralstonia solanacearum

The biological control process mediated by microbes relies on multiple interactions among plants, pathogens and biocontrol agents (BCAs). One such efficient BCA is Bacillus cereus AR156, a bacterial strain that controls a broad spectrum of plant diseases and potentially works as a microbe elicitor of plant immune reactions. It remains unclear, however, whether the interaction between plants and B. cereus AR156 may facilitate composition changes of plant root exudates and whether these changes directly affect the growth of both plant pathogens and B. cereus AR156 itself. Here, we addressed these questions by analyzing the influences of root exudate changes mediated by B. cereus AR156 during biocontrol against tomato bacterial wilt caused by Ralstonia solanacearum. Indeed, some upregulated metabolites in tomato root exudates induced by B. cereus AR156 (REB), such as lactic acid and hexanoic acid, induced the growth and motile ability of in vitro B. cereus AR156 cells. Exogenously applying hexanoic acid and lactic acid to tomato plants showed positive biocontrol efficacy (46.6 and 39.36%) against tomato bacterial wilt, compared with 51.02% by B. cereus AR156 itself. Furthermore, fructose, lactic acid, sucrose and threonine at specific concentrations stimulated the biofilm formation of B. cereus AR156 in Luria-Bertan- Glycerol- Magnesium medium (LBGM), and we also detected more colonized cells of B. cereus AR156 on the tomato root surface after adding these four compounds to the system. These observations suggest that the ability of B. cereus AR156 to induce some specific components in plant root exudates was probably involved in further biocontrol processes

Building generic anatomical models using virtual model cutting and iterative registration

Article deposited according to publisher policy posted on SHERPA/RoMEO, 30/07/2010.YesFunding provided by the Open Access Authors Fund

Mechanical, Toughness and Thermal properties of 2D Material- Reinforced Epoxy Composites

Developing epoxy composites with high thermal conductivity and excellent mechanical properties becomes imperative in electronic and aerospace industries. This study investigates and compares the effect of adding boron nitride (BN) sheets and graphene platelets (GnPs) on the mechanical properties and thermal conductivity of epoxy resin. The study shows that incorporation of BN or GnPs into epoxy matrix significantly enhanced both mechanical properties and thermal conductivity of epoxy composites. At fractions ranging 1–4 wt%, GnPs/epoxy composites provide higher Young’s modulus, fracture toughness (K1c) and critical stress energy release rate (G1c) compared to BN/epoxy composites. The thermal conductivity of the epoxy composites is up to the maximum of 0.33 Wm 1 K 1 at 4 wt% of GnP loading, which is much higher than that of the composites filled with the same loading of BN (0.23 Wm 1 K 1 ). The study emphasizes the importance of adding thin nanosheets (thickness 3–5 nm) at low loadings in developing epoxy composites to achieve desired mechanical and thermal properties