This study is to comprehensively clarify the effect of Nb addition on the particles, austenite grain growth, microstructure evolution, and toughness in the heat-affected zone after high heat input ...welding at 400 kJ cm
−1
for shipbuilding steel plates with Mg deoxidation containing 0.002 and 0.016 wt pct Nb. The Nb addition enhances the dissolution of small particles (< 20 nm) and the coarsening of large particles (> 20 nm) during welding period of
T
> 1300 °C, because the stability of (Ti, Nb)(C, N) particles is reduced caused by the weaker bonding of Ti–C, Nb–N, and Nb–C. With the temperature above 1300 °C during welding, the austenite grain growth rate increases with Nb addition because the particle pinning force reduces by the small-sized particle dissolution and large-size particle coarsening. Nb addition hinders the ferrite transformation with the transformation temperature decreasing from 700–535 °C to 670–520 °C, due to the increased PAG size. Thus, with Nb addition, the microstructures change from high-temperature fine polygonal ferrite in small prior austenite grains (PAGs) to low-temperature coarse intragranular bainite ferrite in large PAGs, reducing the high-angled grain boundary density from 1.3 to 0.5
μ
m
−1
and increasing the effective grain size from 10.4 to 17.6
μ
m. Thus, the toughness at − 40 °C decreases from 127 to 58 J.
Thick high-strength low-alloy (HSLA) steel plates with excellent large heat input welding properties are increasingly demanded to build super-large container ships for the globally flourishing marine ...trade. This article describes the effect of Ca content on the TiN particles, microstructure and impact toughness of the simulated coarse-grained heat-affected zone (CGHAZ) in HSLA steels after large heat input welding at 400 kJ/cm. The quantitative analyses on TiN particles demonstrate that the number densities of the submicron- and nano-scale particles increase with increasing Ca content, but the particle sizes appear to be independent of the Ca content. The prior austenite grains in the CGHAZs of the HSLA steels are comparably coarse, including a small number of extremely large grains, except for 25Ca steel, whose grains are relatively fine and uniform. Moreover, only the impact toughness of the CGHAZ in 25Ca steel is satisfactorily improved with a small test variability, and this could be attributed to the improved precipitation of the submicron-scale TiN particles that effectively refine the grains. Based on the experimental and thermodynamic results, it is strongly recommended to increase the Ca content to > 0.0019 wt pct for the related HSLA steel system in the future steel optimization.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading worldwide, causing a global pandemic. Bat-origin RaTG13 is currently the most phylogenetically related virus. Here we ...obtained the complex structure of the RaTG13 receptor binding domain (RBD) with human ACE2 (hACE2) and evaluated binding of RaTG13 RBD to 24 additional ACE2 orthologs. By substituting residues in the RaTG13 RBD with their counterparts in the SARS-CoV-2 RBD, we found that residue 501, the major position found in variants of concern (VOCs) 501Y.V1/V2/V3, plays a key role in determining the potential host range of RaTG13. We also found that SARS-CoV-2 could induce strong cross-reactive antibodies to RaTG13 and identified a SARS-CoV-2 monoclonal antibody (mAb), CB6, that could cross-neutralize RaTG13 pseudovirus. These results elucidate the receptor binding and host adaption mechanisms of RaTG13 and emphasize the importance of continuous surveillance of coronaviruses (CoVs) carried by animal reservoirs to prevent another spillover of CoVs.
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•The complex structure of RaTG13 RBD with hACE2 was determined•Binding of RaTG13 RBD to 24 additional ACE2 orthologs was evaluated•Residue 501 plays a key role in determining the potential host range of RaTG13•SARS-CoV-2 induces strong cross-protective antibodies to RaTG13 RBD
Structural and molecular analysis of the receptor binding domain of RaTG13, a coronavirus phylogenetically closely related to SARS-CoV-2, bound to the human receptor ACE2 as well as ACE2 orthologs in 24 other species provides a framework to understand its host range as well as the basis of antibody cross-reactivity between the two viruses.
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of the recent pandemic COVID-19, is reported to have originated from bats, with its intermediate host ...unknown to date. Here, we screened 26 animal counterparts of the human ACE2 (hACE2), the receptor for SARS-CoV-2 and SARS-CoV, and found that the ACE2s from various species, including pets, domestic animals and multiple wild animals, could bind to SARS-CoV-2 receptor binding domain (RBD) and facilitate the transduction of SARS-CoV-2 pseudovirus. Comparing to SARS-CoV-2, SARS-CoV seems to have a slightly wider range in choosing its receptor. We further resolved the cryo-electron microscopy (cryo-EM) structure of the cat ACE2 (cACE2) in complex with the SARS-CoV-2 RBD at a resolution of 3 Å, revealing similar binding mode as hACE2 to the SARS-CoV-2 RBD. These results shed light on pursuing the intermediate host of SARS-CoV-2 and highlight the necessity of monitoring susceptible hosts to prevent further outbreaks.
The effect of sodium chloride (NaCl) curing salt content on protein oxidation, lipid oxidation and lipolysis of Chinese dry sausage was investigated. Two groups Chinese dry sausages with 2% and 4% ...(m/m) salt content were studied. The degree of protein oxidation increased during the processes in two groups sausages, while the content of phospholipids decreased, neutral lipids and free fatty acids increased. The degree of protein oxidation, lipid oxidation and lipolysis in 4% NaCl content group was higher than those in 2% NaCl content group, while 4% NaCl content group has higher lipase activity. In conclusion, 4% NaCl may facilitate the protein oxidation, lipid hydrolysis and oxidation in Chinese dry sausage, and the protein oxidation had strong correlation with lipid oxidation and lipolysis. The results could provide a basis for improving the technology of industrial production.
•Preharvest sodium nitroprusside (SNP treatment increased the NO content in ‘Golden Delicious’ apples.•Preharvest SNP treatment inhibited ethylene metabolism.•Preharvest SNP treatment promoted the ...accumulation of sucrose.•Preharvest SNP treatment might be a potential measure for ripening control.
In order to examine the influence of preharvest nitric oxide (NO) treatment on ethylene biosynthesis and soluble sugar metabolism in ‘Golden Delicious’ apples, apple trees were sprayed with 50μM sodium nitroprusside (SNP) (a donor of NO) 14 days before harvest. The results indicated that preharvest SNP treatment can increase the NO content and the NOS activity in apple fruit, therefore, delay the accumulation of ethylene due to its inhibition on the activities of 1-aminocyclopropane-1-carboxylate synthase (ACS) and 1-aminocyclopropane-1-carboxylate oxydase (ACO). Fructose is the main sugar in ‘Golden Delicious’ apple. The synthesis of sucrose was stimulated and the decomposition of sucrose was inhibited by this treatment, thus causing the accumulation of sucrose. We can draw a conclusion that pre-harvest SNP (50μM) treatment can increase the NO content of fruit during storage, while higher NO content can further regulate fruit ripening through its effect on ethylene and sugar metabolism in ‘Golden Delicious’ apple fruit during storage at 18°C.
This study attempted to estimate the maximum size of inclusions in the ultra-low carbon Bake Hardening (BH) steels of automobile exposed panel. The Probable Maximum Sizes (PMS) of inclusions at the ...different steelmaking stages for BH steel with different sulfur contents were predicted by two methods of Statistics of Extreme Values (SEV) and Particle Size Distribution (PSD). The S content does not show a relationship with the PMS prediction of inclusions in the molten steel in which Al2O3 is the main inclusion, while the higher content of S leads to a larger PMS value in the slab, due to more number of large-sized Al2O3-MnS inclusions formed during solidification. The PMS value in the slab is greater than that in the molten steel for BH steel. Thus, the PMS of inclusions in the slab cannot be estimated from the molten steel samples. The SEV can be used to predict well the PMS values at different steelmaking stages for BH steels. However, the PSD of exponential function cannot predict well the PMS value in the slab for BH steel when considering all kinds of inclusions due to the large influence of small-sized MnS with high number density on the PSD of exponential function. When only considering Al2O3-MnS inclusions, the PSD of exponential function can make a reasonable PMS prediction in the slab, because the size distribution of Al2O3-MnS with large size can follow the exponential function.
Rice blast is one of the most devastating diseases, causing a significant reduction in global rice production. Developing and utilizing resistant varieties has proven to be the most efficient and ...cost-effective approach to control blasts. However, due to environmental pressure and intense pathogenic selection, resistance has rapidly broken down, and more durable resistance genes are being discovered. In this paper, a novel wall-associated kinase (WAK) gene,
, which confers resistance to rice blast, was identified through a genome-wide association study (GWAS) utilizing 249 rice accessions. Pb4 comprises an N-terminal signal peptide, extracellular GUB domain, EGF domain, EGF-Ca
domain, and intracellular Ser/Thr protein kinase domain. The extracellular domain (GUB domain, EGF domain, and EGF-Ca
domain) of Pb4 can interact with the extracellular domain of CEBiP. Additionally, its expression is induced by chitin and polygalacturonic acid. Furthermore, transgenic plants overexpressing
enhance resistance to rice blast. In summary, this study identified a novel rice blast-resistant gene,
, and provides a theoretical basis for understanding the role of WAKs in mediating rice resistance against rice blast disease.
The effect of process and storage on the volatiles and odorant profile of Chinese dry sausage was evaluated, as well as its physicochemical parameters. Microbial esterification and wine ...(27.54%–43.35%), and lipid oxidation (11.30%–34.92%) played a key role in flavor profile during process and storage. A significant increase of each volatile was detected during process except gradual decrease of volatiles from spices, while a gradual decrease of each volatile was detected during storage except significant increase of volatiles from lipid oxidation and esterification. 15 and 6 odor-active compounds were respectively correlated (P<0.05) with the process and storage time. Level of heptanal, 1-octen-3-ol, the ethyl of 2-methylbutanoic, 3-methylbutanoic, butanoic, benzoic, hexanoic, heptanoic, octanoic and decanoic acid were best discriminators of process stage, while (E)-2-nonenal, ethyl hexanoate, ethyl heptanoate, and methyl decanoate, were marker compounds of storage time. An objective method was established to evaluate the stages of process and storage for samples.
(anamorph:
) is the pathogen of rice false smut (RFS), which is a destructive rice fungal disease. The albino strain LN02 is a natural white-phenotype mutant of
due to its incapability to produce ...toxic ustilaginoidins. In this study, three strains including the normal strain P1, albino strain LN02, and complemented strain
-1 of the LN02 strain were employed to investigate the activation of the ustilaginoidin biosynthesis gene
in the albino strain LN02 to influence sporulation, conidia germination, pigment production, stress responses, and the inhibition of rice seed germination. The activation of the ustilaginoidin biosynthesis gene
increased fungal tolerances to NaCl-induced osmotic stress, Congo-red-induced cell wall stress, SDS-induced cell membrane stress, and H
O
-induced oxidative stress. The activation of
also increased sporulation, conidia germination, pigment production, and the inhibition of rice seed germination. In addition, the activation of
was able to increase the mycelial growth of the
albino strain LN02 at 23 °C and a pH from 5.5 to 7.5. The findings help in understanding the effects of the activation of
in albino strain LN02 on development, pigment production, stress responses, and the inhibition of rice seed germination by controlling ustilaginoidin biosynthesis.
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