We conducted high‐pressure experiments on hexagonal close packed iron (hcp‐Fe) in MgO, NaCl, and Ne pressure‐transmitting media and found general agreement among the experimental data at 300 K that ...yield the best fitted values of the bulk modulus K0 = 172.7(±1.4) GPa and its pressure derivative K0′ = 4.79(±0.05) for hcp‐Fe, using the third‐order Birch‐Murnaghan equation of state. Using the derived thermal pressures for hcp‐Fe up to 100 GPa and 1800 K and previous shockwave Hugoniot data, we developed a thermal equation of state of hcp‐Fe. The thermal equation of state of hcp‐Fe is further used to calculate the densities of iron along adiabatic geotherms to define the density deficit of the inner core, which serves as the basis for developing quantitative composition models of the Earth's inner core. We determine the density deficit at the inner core boundary to be 3.6%, assuming an inner core boundary temperature of 6000 K.
Key Points
Intercalibrated pressure scales lead to a consistent compression curve of hcp‐iron up to 300 GPa
Thermal equation of state of hcp‐iron is refined by combining static and dynamic data
The inner core density deficit is 3.6% at an inner core boundary temperature of 6000 K
•Pemetrexed only exerts weak cytotoxic effect against HepG2 cells.•Pemetrexed induces cyto-protective autophagy in HepG2 cells, counteracting cell death.•Beclin-1 RNAi sensitizes pemetrexed’s ...activity in HepG2 cells.•MEK/ERK activation is required for autophagy induction by pemetrexed.•MEK/ERK inhibition sensitizes pemetrexed’s activity in HepG2 cells.
Identification of efficient chemo-therapeutic/chemo-preventive agents for treatment of hepatocellular carcinoma (HCC) is important. In this study, we examined the activity of pemetrexed, an anti-folate chemotherapy drug, against HepG2 human HCC cells. Pemetrexed treatment in vitro exerted weak but significant cytotoxic activity against HepG2 cells. When analyzing the possible pemetrexed-resistance factors, we indentified that pemetrexed treatment in HepG2 cells induced cyto-protective autophagy activation, evidenced by GFP–light chain 3B (LC3B) puncta formation, p62 downregulation and Beclin-1/LC3B-II upregulation. Correspondingly, autophagy inhibitors, including bafliomycin A1, 3-methyladenine and chloroquine, enhanced pemetrexed-induced cytotoxicity against HepG2 cells. Further, RNAi-mediated knockdown of Beclin-1 in HepG2 cells also increased pemetrexed sensitivity. Pemetrexed activated MEK (mitogen-activated protein kinase/ERK kinase)/ERK (extracellular-signal-regulated kinase) signaling in HepG2 cells, which was required for autophagy induction. Pharmacological inhibition of MEK/ERK activation attenuated pemetrexed-induced autophagy, enhanced HepG2 cell death and apoptosis. In summary, pemetrexed activates MEK/ERK-dependent cyto-protective autophagy, and inhibition of this pathway potentiates pemetrexed’s activity in HepG2 cells.
Flocculation has a great influence on the biogeochemical cycle by altering the particle size, density and settling velocity of suspended particulate matter (SPM) from coastal to shelf sea areas. ...However, the flocculation process in the shelf sea areas of China has not been systematically studied. In this study, the influencing mechanism of the North Yellow Sea cold water mass (NYSCWM) on the distribution and flocculation process of SPM is studied based on a comprehensive investigation during the summer of 2016. The results revealed that the mass concentration and turbidity of SPM showed a decreasing trend from coastal to offshore areas and an increasing trend from surface to near-benthic layers. Sediments from the Shandong subaqueous clinoform that were resuspended by the tidal mixing effect were the main source of inorganic SPM in the North Yellow Sea in summer. The existence of the bottom cold water mass enhanced the thermocline and pycnocline in the North Yellow Sea shelf area. The pycnocline obstructed the vertical diffusion of nutrients in the NYSCWM, resulting in a subsurface maximum chlorophyll a (chl a) layer, which further contributed to the maximum subsurface volume concentration of SPM. Flocculation was ubiquitous in the study area and was the main reason for the asynchronous variability in the mass concentration, turbidity and volume concentration of SPM. Three different kinds of flocculation mechanisms were identified, including the effects of biological activities in water masses above the NYSCWM, physicochemical effects in the near-benthic nepheloid layer within the NYSCWM, and their combined effects in shallow coastal areas. The flocculation of SPM enhanced the transport of particles from the surface to the bottom of the water column and made an important contribution to the formation of the North Yellow Sea mud deposit.
•The CWM changed the marine physical and biological environments, resulting in variations in SPM flocculation conditions.•Three flocculation mechanisms, dominated by biological activity, physicochemical effects and their coeffects are proposed.•The flocculation processes of SPM play important roles in the formation of mud deposits in the North Yellow Sea.
The ability of end-tidal carbon dioxide (ΔEtCO2) for predicting fluid responsiveness has been extensively studied with conflicting results. This meta-analysis aimed to explore the value of ΔEtCO2 for ...predicting fluid responsiveness during the passive leg raising (PLR) test in patients with mechanical ventilation.
PubMed, Embase, and Cochrane Central Register of Controlled Trials were searched up to November 2021. The diagnostic odds ratio (DOR), sensitivity, and specificity were calculated. The summary receiver operating characteristic curve was estimated, and the area under the curve (AUROC) was calculated. Q test and I
statistics were used for study heterogeneity and publication bias was assessed by Deeks' funnel plot asymmetry test. We performed meta-regression analysis for heterogeneity exploration and sensitivity analysis for the publication bias.
Overall, six studies including 298 patients were included in this review, of whom 149 (50%) were fluid responsive. The cutoff values of ΔEtCO2 in four studies was 5%, one was 5.8% and the other one was an absolute increase 2 mmHg. Heterogeneity between studies was assessed with an overall Q = 4.098, I
= 51%, and P = 0.064. The pooled sensitivity and specificity for the overall population were 0.79 (95% CI 0.72-0.85) and 0.90 (95% CI 0.77-0.96), respectively. The DOR was 35 (95% CI 12-107). The pooled AUROC was 0.81 (95% CI 0.77-0.84). On meta-regression analysis, the number of patients was sources of heterogeneity. The sensitivity analysis showed that the pooled DOR ranged from 21 to 140 and the pooled AUC ranged from 0.92 to 0.96 when one study was omitted.
Though the limited number of studies included and study heterogeneity, our meta-analysis confirmed that the ΔEtCO2 performed moderately in predicting fluid responsiveness during the PLR test in patients with mechanical ventilation.
•An analytical model is developed to predict the cavitation induced undercooling, grain nucleation and the solidified grain size.•Cavitation bubble implosion in metallic melts were imaged in-situ by ...ultrafast synchrotron X-ray imaging.•The model takes into account of ultrasound input intensity, cavitation bubble size and the effect of melt temperature.•The solidified grain size of different alloys were calculated using this model and compared with the experimental data.
Microstructural refinement of metallic alloys via ultrasonic melt processing (USMP) is an environmentally friendly and promising method. However, so far there has been no report in open literature on how to predict the solidified microstructures and grain size based on the ultrasound processing parameters.In this paper, an analytical model is developed to calculate the cavitation enhanced undercooling and the USMP refined solidification microstructure and grain size for Al-Cu alloys. Ultrafast synchrotron X-ray imaging and tomography techniques were used to collect the real-time experimental data for validating the model and the calculated results. The comparison between modeling and experiments reveal that there exists an effective ultrasound input power intensity for maximizing the grain refinement effects for the Al-Cu alloys, which is in the range of 20-45 MW/m2. In addition, a monotonous increase in temperature during USMP has negative effect on producing new nuclei, deteriorating the benefit of microstructure refinement due to the application of ultrasound.
Respiratory variations in the inferior vena cava diameter (ΔIVCD) have been studied extensively with respect to their value in predicting fluid responsiveness, but the results are conflicting. The ...aim of this meta-analysis was to explore the value of ΔIVCD for predicting fluid responsiveness in patients with circulatory shock receiving mechanical ventilation.
PubMed, Embase, and the Cochrane Central Register of Controlled Trials were searched up to June 2017. The diagnostic OR (DOR), sensitivity, and specificity were calculated. The summary ROC curve was estimated, and the area under the ROC curve (AUROC) was calculated.
Overall, 603 patients were included in this review, 324 (53.7%) of whom were fluid-responsive. The cutoff values of ΔIVCD varied across studies, ranging from 8% to 21%. Heterogeneity between studies was assessed with an overall Q = 0.069, I
= 0%, and P = 0.483. The pooled sensitivity and specificity for the overall population were 0.69 (95% CI, 0.51-0.83) and 0.80 (95% CI, 0.66-0.89), respectively. The DOR was 9.28 (95% CI, 2.33-36.98). AUROCs were reported in five studies. Overall, the pooled AUROC was 0.82 (95% CI, 0.79-0.85).
The findings of this study suggest that the ΔIVCD performed moderately well in predicting fluid responsiveness in patients with circulatory shock receiving mechanical ventilation.
The geomechanical properties of the stratigraphic sequences strongly influence the land surface subsidence, as the latter can be caused by the sediment compaction. Depositional units of transitional ...environments such as coastal plain and deltas are characterized by a high lithological variability due to the history and complexity of the sedimentary processes. Therefore, detailed modeling of the stratigraphic architecture is necessary to better understand the land surface subsidence process and accurately estimate its rates. The frequent avulsion and rearrangement of the channel network in the modern Yellow River delta since 1855 has led to the rapid accumulation and deposition of large amounts of sediment in the delta plain. The compaction of the substratum sediment due to the new sediment load and the consolidation of younger deposits caused land surface subsidence. We used 108 sediment core data covering the delta and obtained detailed stratigraphic structural information. A detailed distribution of clay and soft clayey soils, which are the primary contributors to land subsidence, was identified. Furthermore, the compaction rates and the consolidation at time of the subaerial area and neritic area for the entire modern Yellow River delta were estimated. We also analyzed the characteristics of present land subsidence by combining a ground movement dataset obtained by high-resolution topographic surveys with Synthetic Aperture Radar (SAR) Interferometry (InSAR) of satellite images. The results show that during the early stages of the development of the active deltaic lobe, the compaction of neritic sediments was the primary contributor to initial subsidence. Furthermore, combined with the relevant sedimentary age and environment determined by previous studies, we found that the spatial variation in compaction-induced subsidence in the subaerial deltaic area over time is closely related to the historical distributions of the river channels in the modern Yellow River delta. Our findings, providing a better characterization of the spatial and time heterogeneity of the land surface subsidence of both subaerial and submarine areas, significantly improved the previous knowledge on land subsidence of the Yellow River delta. Our results also demonstrate that the subaerial delta becomes increasingly stable over time with the gradual decrease in the average subsidence rate of each deltaic lobe.
•Expounding evolution history of compaction-induce subsidence in Yellow River delta•Exploring the relationship of land subsidence and distributions of deltaic channels•Proposing a compaction subsidence process accompanying with delta progradation
Aerosol particles originated from anthropogenic emissions, volcanic eruptions, biomass burning, and fossil combustion emissions, and their radiative effect is one of the most uncertain factors in ...climate change. Meanwhile, aerosol particles in fine particle size could also cause irreversible effects on the human respiratory system. This study attempted to analyse the spatial and temporal variations of global aerosol optical depth (AOD, 550 nm) during 1980–2018 using MERRA-2 aerosol reanalysis products and to investigate the effects of natural/anthropogenic emissions of different types of aerosols on AOD values. The results show that the global annual mean AOD values kept high levels with significant fluctuations during 1980–1995 and showed a consistent decreasing and less volatile trend after 1995. Spatially, the AOD values are relatively higher in the Northern Hemisphere than in the Southern Hemisphere, especially in North Africa (0.329), Northern India (0.235), and Eastern China (0.347), because of the intensive natural/anthropogenic aerosol emissions there. The sulphate-based aerosols emitted by biomass burning and anthropogenic emissions are the main types of aerosols worldwide, especially in densely populated and industrialized regions such as East Asia and Europe. Dust aerosols are also the main aerosol type in desert areas. For example, the AOD and AODP values for the Sahara Desert are 0.3178 and 75.32%, respectively. Both black carbon aerosols (BC) and organic carbon aerosols (OC) are primary or secondary from carbon emissions of fossil fuels, biomass burning, and open burning. Thus, the regions with high BC and OC aerosol loadings are mainly located in densely populated or vegetated areas such as East Asia, South Asia, and Central Africa. Sea salt aerosols are mainly found in coastline areas along the warm current pathway. This study could help relevant researchers in the fields of atmospheric science, environmental protection, air pollution, and ecological environment to understand the global spatial–temporal variations and main driving factors of aerosol loadings.
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