The effect of cerium on inclusions in an ultra-low-carbon Al-killed steel was studied at 1873 K (1600 °C) using laboratory experiments. The content of cerium in the steel varied from 0 to ...0.028 wt pct. The contents of the total oxygen (T.O), total nitrogen (T.N), total sulfur (T.S), total cerium (T.Ce) and dissolved aluminum (Al) in the steel samples 1, 5, 10 and 30 minutes after adding cerium were measured, and inclusions were characterized using an automatic scanning electron microscope. It was found that a cerium-concentrated zone formed after the cerium alloy was added to the molten steel. Many inclusions were generated in the cerium-concentrated zone and then disappeared with the decrease of the cerium content. The variation of the inclusion composition was Al
2
O
3
→ CeAlO
3
→ Ce
2
O
2
S → Ce
2
O
2
S + CeS with the increasing cerium content in the steel, which agreed well with the thermodynamic analysis. The value of T.Ce/T.O was able to evaluate and predict the type of inclusions. A prediction model of the composition of inclusions was established based on thermodynamic calculation and mass balance and was validated by experimental data. When the value of T.Ce/(T.S + T.O) was ≥ 4.4, the average composition of inclusions changed little since most inclusions were fully modified.
Peroxisomes account for ~35% of total H2O2 generation in mammalian tissues. Peroxisomal ACOX1 (acyl‐CoA oxidase 1) is the first and rate‐limiting enzyme in fatty acid β‐oxidation and a major producer ...of H2O2. ACOX1 dysfunction is linked to peroxisomal disorders and hepatocarcinogenesis. Here, we show that the deacetylase sirtuin 5 (SIRT5) is present in peroxisomes and that ACOX1 is a physiological substrate of SIRT5. Mechanistically, SIRT5‐mediated desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation in both cultured cells and mouse livers. Deletion of SIRT5 increases H2O2 production and oxidative DNA damage, which can be alleviated by ACOX1 knockdown. We show that SIRT5 downregulation is associated with increased succinylation and activity of ACOX1 and oxidative DNA damage response in hepatocellular carcinoma (HCC). Our study reveals a novel role of SIRT5 in inhibiting peroxisome‐induced oxidative stress, in liver protection, and in suppressing HCC development.
Synopsis
This study reveals a role for SIRT5 in regulating peroxisomal H2O2 and ROS homeostasis and indicates its potential function in liver protection and hepatocellular carcinoma suppression.
SIRT5 is localized in peroxisomes where it controls H2O2 metabolism.
SIRT5‐mediated desuccinylation inhibits ACOX1 activity by suppressing its active dimer formation.
SIRT5 downregulation increases ACOX1 activity and oxidative DNA damage response in HCC.
This study reveals a role for SIRT5 in regulating peroxisomal H2O2 and ROS homeostasis and indicates its potential function in liver protection and hepatocellular carcinoma suppression.
Floods caused by breaches of embankment and landslide dams are not only a tremendous geological disaster, destroying people's lives and property, they also strongly shape the appearance of the ...landscape in the inundation area. This review addresses embankment and landslide dam breaches, with a particular focus on documented failure cases, laboratory and field experiments, as well as empirically and physically based models. The state of the art of physical and mathematical modeling technologies of underlying breach mechanisms and processes are also reviewed. First, the distribution, breach parameters, and failure modes of documented failure cases are analyzed. Second, based on physical model tests at different scales around the world, the breach processes of embankment and landslide dams caused by overtopping or piping/seepage are studied in depth. The breach characteristics for each type of dam are summarized. Third, typical empirically or physically based mathematical models are reviewed with a focus on artificially formed dams (i.e., earthfill, clay core rockfill, and concrete face rockfill dams) or naturally formed dams (i.e., landslide dams). Both uncertainties and limitations associated with formulations and calculating parameters of these mathematical models are also discussed. Finally, recommendations toward a better understanding of breach mechanisms and further development of mathematical models are proposed.
Due to the characteristics of soft soil foundations in port engineering construction, there is a problem of insufficient bearing capacity, which needs to be treated. This paper analyzes the ...construction process and key points of the dynamic compaction method, vacuum preloading method, and vibroflotation method, and expounds on the advantages and disadvantages. The cost of different methods is compared. It can be seen that compared with other methods, the vibration impact method has a simple construction process and low cost.
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•Combined effects of MPs and BHA on zebrafish embryos/larvae were evaluated.•MPs promoted the accumulation of BHA in zebrafish larvae.•MPs enhanced the toxicity of BHA in larvae ...development.•Coexposure disturbed arachidonic acid, glycerophospholipid, and lipids metabolism.
Coexposure of MPs and other contaminants adsorbed from the environment has raised many attentions, but the understanding of the combined effects of MPs and plastic additives are limited. Butylated hydroxyanisole (BHA), a widely used synthetic phenolic antioxidant in plastics, has gained high concerns due to their unintended environmental release and potential threat to aquatic organisms. This study was conducted to reveal the influences of MPs on the bioaccumulation and developmental toxicity of BHA in zebrafish larvae. As a result, MPs promoted the accumulation of BHA in zebrafish larvae and enhanced the toxicity of BHA in larvae development manifested by reduced hatching rates, increased malformation rates and decreased calcified vertebrae. Although the concentration of MPs was not sufficient to cause obvious developmental toxicity, the impacts of MPs on thyroid hormones status might contribute to the aggravated join toxicity. The metabolomic mechanism was revealed to be that the coexposure of BHA and MPs affected the development of zebrafish larvae via disturbing the metabolism of arachidonic acid, glycerophospholipid, and lipids. Our results emphasized that MPs, even at the nontoxic concentrations, in combination with additives caused health risk that should not be ignored.
Abstract
Background
Ferroptosis is a new type of nonapoptotic cell death model that was closely related to reactive oxygen species (ROS) accumulation. Seawater drowning-induced acute lung injury ...(ALI) which is caused by severe oxidative stress injury, has been a major cause of accidental death worldwide. The latest evidences indicate nuclear factor (erythroid-derived 2)-like 2 (Nrf2) suppress ferroptosis and maintain cellular redox balance. Here, we test the hypothesis that activation of Nrf2 pathway attenuates seawater drowning-induced ALI via inhibiting ferroptosis.
Methods
we performed studies using Nrf2-specific agonist (dimethyl fumarate), Nrf2 inhibitor (ML385), Nrf2-knockout mice and ferroptosis inhibitor (Ferrostatin-1) to investigate the potential roles of Nrf2 on seawater drowning-induced ALI and the underlying mechanisms.
Results
Our data shows that Nrf2 activator dimethyl fumarate could increase cell viability, reduced the levels of intracellular ROS and lipid ROS, prevented glutathione depletion and lipid peroxide accumulation, increased
FTH1
and
GPX4
mRNA expression, and maintained mitochondrial membrane potential in MLE-12 cells. However, ML385 promoted cell death and lipid ROS production in MLE-12 cells. Furthermore, the lung injury became more aggravated in the Nrf2-knockout mice than that in WT mice after seawater drowning.
Conclusions
These results suggested that Nrf2 can inhibit ferroptosis and therefore alleviate ALI induced by seawater drowning. The effectiveness of ferroptosis inhibition by Nrf2 provides a novel therapeutic target for seawater drowning-induced ALI.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
•Macro-properties of concrete at cryogenic temperature were review.•Thermal properties of concrete at cryogenic temperature were discussed.•Deterioration mechanism of concrete at cryogenic ...temperature were summarized.
Cryogenic temperature has been widely recognized as one of the extreme environments for the application of concrete. Exposures to the cryogenic temperature may remarkably deteriorate the properties of concrete and thus shortening the service life of structures. This paper presents a comprehensive overview of cryogenic temperature effects on the mechanical properties, freeze–thaw failure, permeabilities and cracking of concrete. The influence of cryogenic temperature on the thermal parameters and deformation of concrete is discussed from the thermodynamic point of view. Based on the phase transformation process and structural characteristics of pore water in concrete at cryogenic temperature, the strengthening mechanism of mechanical properties at cryogenic temperature and the deterioration mechanism under cryogenic freeze–thaw cycles of concrete are analyzed and summarized. Generally, the mechanical properties of concrete at cryogenic temperature are improved whereas their degradation rate under cryogenic freeze–thaw cycles is much faster than that under the ordinary freeze–thaw condition. Meanwhile, compared with ambient temperature, the thermal properties of concrete vary greatly at cryogenic temperature. It is concluded that the phase transformation and migration of pore water in concrete have obvious influence on the variations observed in its properties. Hence, different models are proposed to understand the deterioration mechanism of concrete performance at cryogenic temperature.
Mixing should be optimized in anaerobic digestion (AD) systems to achieve excellent biomaterials production in the sewage sludge (SS) management in wastewater treatment plant. AD depends on the ...coordinated activity of hydrolysis, acidification and methanogenesis. However, the effect of mixing intensity on characteristics of hydrolysis and acidification in AD of SS is still poorly understood. This study focused on the mixing intensity (30, 60, 90 and 120 rpm) effect on the characteristics of dissolved organic matter (DOM) and the key microorganisms in the hydrolysis and acidification of SS. Results showed that enhanced hydrolysis and acidification efficiency was obtained at mixing of 90 and 120 rpm (p < 0.05), while the maximum acetic acid (388 ± 21 mg/L) was produced at 90 rpm. Mixing at 90 rpm enhanced the release of protein and polysaccharide as well as humic acid. Further analyses of DOM molecular features revealed that 90 rpm led to the highest molecular diversity and easily biodegradable molecules (lipid and proteins/amino sugars), which contributed to the maximum hydrolysis and acidification efficiency. Firmicutes and Actinobacteria significantly increased with mixing intensity (p<0.05), and Chloroflexi and Fusobacteria were enriched at mixing of 90 rpm, which favored the hydrolysis of SS. The enrichment of Clostridium XI and Clostridium sensu stricto contributed to the acidification of DOM at 90 and 120 rpm. The results of this study can advance our knowledge about mixing intensity effects on the AD systems of SS. This research also showed how increasing mixing intensity to a relatively high speed can enhance the hydrolysis and acidification efficiency of SS.
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•Mixing at 90 rpm led to the maximum hydrolysis and acidification efficiency.•The release of protein, polysaccharide and humic acid was enhanced at 90 rpm.•The highest biodegradable molecules contributed to the maximum HAP efficiency.•Variations of mixing intensity induced clear differences in bacterial community.
Staphylococcus aureus is one of the major pathogens causing mastitis in dairy herds. The colonization of dairy cows and subsequent contamination of raw milk by S. aureus, especially strains ...exhibiting multidrug resistance and biofilm-forming and toxin-producing abilities, remains an important issue for both dairy farmers and public health. In this study, we investigated the prevalence, antimicrobial susceptibility, biofilm formation, and genetic diversity of S. aureus from subclinical bovine mastitis in dairy farms located in southern Xinjiang, China. Sixty-five isolates from 84 subclinical mastitic milk samples were identified as S. aureus. The resistance rates to penicillin, erythromycin, clindamycin, tetracycline, gentamicin, linezolid, rifampicin, quinupudin-dafupudin, ciprofloxacin, norfloxacin, and chloramphenicol were 58.5, 44.6, 40.0, 18.5, 12.3, 10.8, 9.2, 6.2, 4.6, 4.6, and 1.5%, respectively. All isolates were susceptible to cefoxitin, sulfamethoxazole-trimethoprim, and vancomycin. Isolates from farm A showed a significantly higher resistance rate to tetracycline (16.9%) than those from farm B (1.5%). The most frequently detected virulence factors were hla (96.9%, 63/65) and hlb (100.0%, 65/65). The percentage rates of the staphylococcal enterotoxin genes sea, sec, sed, seg, seh, sei, and sej in S. aureus isolates were 4.6, 33.8, 27.7, 3.1, 41.5, 41.5, and 7.7%, respectively. The percentage rate of the sec gene in isolates from farm B (30.8%) was significantly higher than that of farm A (3.1%). The percentage rates of the tsst and pvl genes in S. aureus isolates were 26.2 and 40.0%. The percentage rate of the pvl gene in isolates from farm B (32.3%) was significantly higher than that of farm A (7.7%). The adhesion molecules fnbA, fnbB, clfA, clfB, and cna were detected in 21 (32.3%), 23 (35.4%), 65 (100.0%), 65 (100.0%), and 65 (100.0%) isolates, respectively. The percentage rates of the icaA, sarA, tcaR, ccp, luxS, and sigB genes in S. aureus isolates were 69.2, 100.0, 86.2, 95.4, 84.6, and 100.0%, respectively. The fnbB and icaA genes were more frequently detected in isolates from farm A (29.2 and 40.0%, respectively) than those from farm B (6.2 and 29.2%, respectively). The luxS gene was more often found in isolates from farm B (50.8%) than those from farm A (33.8%). Using the microplate method, 61.5, 26.2, and 10.8% of the isolates showed weak, moderate, and strong biofilm-forming abilities, respectively. Different clonal complex (CC) and spa-types were identified, including CC81, CC398, CC88, CC5405, and CC5406. Importantly, in this study we report for the first time 41 new sequence types (ST) among 44 distinct ST. These results indicated high genetic diversity of S. aureus involved in subclinical bovine mastitis in southern Xinjiang, China. The results also showed that S. aureus from subclinical bovine mastitis cases in southern Xinjiang, China, were mainly resistant to β-lactams, erythromycin, and clindamycin. Also, biofilm- and adhesion-related genes, which are increasingly known as important virulence factors in the pathogenesis of S. aureus infections, were detected at a high rate. This study could help identify predominant clones and provide surveillance measures to decrease or eliminate S. aureus contamination in raw milk of dairy cows with subclinical mastitis.
In the current study, a three-dimensional mathematical model, combining the large eddy simulation (LES) turbulent model, volume of fluid (VOF) multiphase model, and discrete phase model (DPM), was ...established to investigate the molten steel, liquid slag, air phase, and argon bubble four-phase flow in a continuous casting (CC) mold. The interaction between the argon bubbles and continuous phases was considered to achieve the two-way coupled model. The slag entrainment was quantitatively evaluated using a user-defined function (UDF), including the size, spatial distribution, number, and velocity of the entrained slag droplet. The location, velocity, and probability of the slag entrainment on the entire meniscus were revealed. The four-phase flow inside the mold presented a transient asymmetric distribution. The contribution of each interphase force at different locations was evaluated and the drag force and buoyancy force were the dominant forces acting on the bubbles. The drag force, lift force, pressure gradient force, and virtual mass force had approximately the same magnitude in locations where the bubbles and liquid interacted violently. The level fluctuation gradually decreased from the narrow face to the submerged entry nozzle (SEN), and the net slag entrainment rate at 0.13 m below the initial steel slag interface was 0.05376 kg/s under the current double roll flow. The slag entrainment mainly occurred near the one-quarter width of the mold and the region between the SEN and the wide face. Most slag droplets had an average diameter of 2 to 5 mm, and a fitting formula for the diameter and percentage of slag droplets was proposed.
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